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1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2018 Facebook */
3
4#include <uapi/linux/btf.h>
5#include <uapi/linux/bpf.h>
6#include <uapi/linux/bpf_perf_event.h>
7#include <uapi/linux/types.h>
8#include <linux/seq_file.h>
9#include <linux/compiler.h>
10#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/slab.h>
13#include <linux/anon_inodes.h>
14#include <linux/file.h>
15#include <linux/uaccess.h>
16#include <linux/kernel.h>
17#include <linux/idr.h>
18#include <linux/sort.h>
19#include <linux/bpf_verifier.h>
20#include <linux/btf.h>
21#include <linux/btf_ids.h>
22#include <linux/bpf_lsm.h>
23#include <linux/skmsg.h>
24#include <linux/perf_event.h>
25#include <linux/bsearch.h>
26#include <linux/kobject.h>
27#include <linux/sysfs.h>
28
29#include <net/netfilter/nf_bpf_link.h>
30
31#include <net/sock.h>
32#include <net/xdp.h>
33#include "../tools/lib/bpf/relo_core.h"
34
35/* BTF (BPF Type Format) is the meta data format which describes
36 * the data types of BPF program/map. Hence, it basically focus
37 * on the C programming language which the modern BPF is primary
38 * using.
39 *
40 * ELF Section:
41 * ~~~~~~~~~~~
42 * The BTF data is stored under the ".BTF" ELF section
43 *
44 * struct btf_type:
45 * ~~~~~~~~~~~~~~~
46 * Each 'struct btf_type' object describes a C data type.
47 * Depending on the type it is describing, a 'struct btf_type'
48 * object may be followed by more data. F.e.
49 * To describe an array, 'struct btf_type' is followed by
50 * 'struct btf_array'.
51 *
52 * 'struct btf_type' and any extra data following it are
53 * 4 bytes aligned.
54 *
55 * Type section:
56 * ~~~~~~~~~~~~~
57 * The BTF type section contains a list of 'struct btf_type' objects.
58 * Each one describes a C type. Recall from the above section
59 * that a 'struct btf_type' object could be immediately followed by extra
60 * data in order to describe some particular C types.
61 *
62 * type_id:
63 * ~~~~~~~
64 * Each btf_type object is identified by a type_id. The type_id
65 * is implicitly implied by the location of the btf_type object in
66 * the BTF type section. The first one has type_id 1. The second
67 * one has type_id 2...etc. Hence, an earlier btf_type has
68 * a smaller type_id.
69 *
70 * A btf_type object may refer to another btf_type object by using
71 * type_id (i.e. the "type" in the "struct btf_type").
72 *
73 * NOTE that we cannot assume any reference-order.
74 * A btf_type object can refer to an earlier btf_type object
75 * but it can also refer to a later btf_type object.
76 *
77 * For example, to describe "const void *". A btf_type
78 * object describing "const" may refer to another btf_type
79 * object describing "void *". This type-reference is done
80 * by specifying type_id:
81 *
82 * [1] CONST (anon) type_id=2
83 * [2] PTR (anon) type_id=0
84 *
85 * The above is the btf_verifier debug log:
86 * - Each line started with "[?]" is a btf_type object
87 * - [?] is the type_id of the btf_type object.
88 * - CONST/PTR is the BTF_KIND_XXX
89 * - "(anon)" is the name of the type. It just
90 * happens that CONST and PTR has no name.
91 * - type_id=XXX is the 'u32 type' in btf_type
92 *
93 * NOTE: "void" has type_id 0
94 *
95 * String section:
96 * ~~~~~~~~~~~~~~
97 * The BTF string section contains the names used by the type section.
98 * Each string is referred by an "offset" from the beginning of the
99 * string section.
100 *
101 * Each string is '\0' terminated.
102 *
103 * The first character in the string section must be '\0'
104 * which is used to mean 'anonymous'. Some btf_type may not
105 * have a name.
106 */
107
108/* BTF verification:
109 *
110 * To verify BTF data, two passes are needed.
111 *
112 * Pass #1
113 * ~~~~~~~
114 * The first pass is to collect all btf_type objects to
115 * an array: "btf->types".
116 *
117 * Depending on the C type that a btf_type is describing,
118 * a btf_type may be followed by extra data. We don't know
119 * how many btf_type is there, and more importantly we don't
120 * know where each btf_type is located in the type section.
121 *
122 * Without knowing the location of each type_id, most verifications
123 * cannot be done. e.g. an earlier btf_type may refer to a later
124 * btf_type (recall the "const void *" above), so we cannot
125 * check this type-reference in the first pass.
126 *
127 * In the first pass, it still does some verifications (e.g.
128 * checking the name is a valid offset to the string section).
129 *
130 * Pass #2
131 * ~~~~~~~
132 * The main focus is to resolve a btf_type that is referring
133 * to another type.
134 *
135 * We have to ensure the referring type:
136 * 1) does exist in the BTF (i.e. in btf->types[])
137 * 2) does not cause a loop:
138 * struct A {
139 * struct B b;
140 * };
141 *
142 * struct B {
143 * struct A a;
144 * };
145 *
146 * btf_type_needs_resolve() decides if a btf_type needs
147 * to be resolved.
148 *
149 * The needs_resolve type implements the "resolve()" ops which
150 * essentially does a DFS and detects backedge.
151 *
152 * During resolve (or DFS), different C types have different
153 * "RESOLVED" conditions.
154 *
155 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
156 * members because a member is always referring to another
157 * type. A struct's member can be treated as "RESOLVED" if
158 * it is referring to a BTF_KIND_PTR. Otherwise, the
159 * following valid C struct would be rejected:
160 *
161 * struct A {
162 * int m;
163 * struct A *a;
164 * };
165 *
166 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
167 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
168 * detect a pointer loop, e.g.:
169 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
170 * ^ |
171 * +-----------------------------------------+
172 *
173 */
174
175#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
176#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
177#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
178#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
179#define BITS_ROUNDUP_BYTES(bits) \
180 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
181
182#define BTF_INFO_MASK 0x9f00ffff
183#define BTF_INT_MASK 0x0fffffff
184#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
185#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
186
187/* 16MB for 64k structs and each has 16 members and
188 * a few MB spaces for the string section.
189 * The hard limit is S32_MAX.
190 */
191#define BTF_MAX_SIZE (16 * 1024 * 1024)
192
193#define for_each_member_from(i, from, struct_type, member) \
194 for (i = from, member = btf_type_member(struct_type) + from; \
195 i < btf_type_vlen(struct_type); \
196 i++, member++)
197
198#define for_each_vsi_from(i, from, struct_type, member) \
199 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
200 i < btf_type_vlen(struct_type); \
201 i++, member++)
202
203DEFINE_IDR(btf_idr);
204DEFINE_SPINLOCK(btf_idr_lock);
205
206enum btf_kfunc_hook {
207 BTF_KFUNC_HOOK_COMMON,
208 BTF_KFUNC_HOOK_XDP,
209 BTF_KFUNC_HOOK_TC,
210 BTF_KFUNC_HOOK_STRUCT_OPS,
211 BTF_KFUNC_HOOK_TRACING,
212 BTF_KFUNC_HOOK_SYSCALL,
213 BTF_KFUNC_HOOK_FMODRET,
214 BTF_KFUNC_HOOK_CGROUP_SKB,
215 BTF_KFUNC_HOOK_SCHED_ACT,
216 BTF_KFUNC_HOOK_SK_SKB,
217 BTF_KFUNC_HOOK_SOCKET_FILTER,
218 BTF_KFUNC_HOOK_LWT,
219 BTF_KFUNC_HOOK_NETFILTER,
220 BTF_KFUNC_HOOK_MAX,
221};
222
223enum {
224 BTF_KFUNC_SET_MAX_CNT = 256,
225 BTF_DTOR_KFUNC_MAX_CNT = 256,
226 BTF_KFUNC_FILTER_MAX_CNT = 16,
227};
228
229struct btf_kfunc_hook_filter {
230 btf_kfunc_filter_t filters[BTF_KFUNC_FILTER_MAX_CNT];
231 u32 nr_filters;
232};
233
234struct btf_kfunc_set_tab {
235 struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
236 struct btf_kfunc_hook_filter hook_filters[BTF_KFUNC_HOOK_MAX];
237};
238
239struct btf_id_dtor_kfunc_tab {
240 u32 cnt;
241 struct btf_id_dtor_kfunc dtors[];
242};
243
244struct btf {
245 void *data;
246 struct btf_type **types;
247 u32 *resolved_ids;
248 u32 *resolved_sizes;
249 const char *strings;
250 void *nohdr_data;
251 struct btf_header hdr;
252 u32 nr_types; /* includes VOID for base BTF */
253 u32 types_size;
254 u32 data_size;
255 refcount_t refcnt;
256 u32 id;
257 struct rcu_head rcu;
258 struct btf_kfunc_set_tab *kfunc_set_tab;
259 struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
260 struct btf_struct_metas *struct_meta_tab;
261
262 /* split BTF support */
263 struct btf *base_btf;
264 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
265 u32 start_str_off; /* first string offset (0 for base BTF) */
266 char name[MODULE_NAME_LEN];
267 bool kernel_btf;
268};
269
270enum verifier_phase {
271 CHECK_META,
272 CHECK_TYPE,
273};
274
275struct resolve_vertex {
276 const struct btf_type *t;
277 u32 type_id;
278 u16 next_member;
279};
280
281enum visit_state {
282 NOT_VISITED,
283 VISITED,
284 RESOLVED,
285};
286
287enum resolve_mode {
288 RESOLVE_TBD, /* To Be Determined */
289 RESOLVE_PTR, /* Resolving for Pointer */
290 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
291 * or array
292 */
293};
294
295#define MAX_RESOLVE_DEPTH 32
296
297struct btf_sec_info {
298 u32 off;
299 u32 len;
300};
301
302struct btf_verifier_env {
303 struct btf *btf;
304 u8 *visit_states;
305 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
306 struct bpf_verifier_log log;
307 u32 log_type_id;
308 u32 top_stack;
309 enum verifier_phase phase;
310 enum resolve_mode resolve_mode;
311};
312
313static const char * const btf_kind_str[NR_BTF_KINDS] = {
314 [BTF_KIND_UNKN] = "UNKNOWN",
315 [BTF_KIND_INT] = "INT",
316 [BTF_KIND_PTR] = "PTR",
317 [BTF_KIND_ARRAY] = "ARRAY",
318 [BTF_KIND_STRUCT] = "STRUCT",
319 [BTF_KIND_UNION] = "UNION",
320 [BTF_KIND_ENUM] = "ENUM",
321 [BTF_KIND_FWD] = "FWD",
322 [BTF_KIND_TYPEDEF] = "TYPEDEF",
323 [BTF_KIND_VOLATILE] = "VOLATILE",
324 [BTF_KIND_CONST] = "CONST",
325 [BTF_KIND_RESTRICT] = "RESTRICT",
326 [BTF_KIND_FUNC] = "FUNC",
327 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
328 [BTF_KIND_VAR] = "VAR",
329 [BTF_KIND_DATASEC] = "DATASEC",
330 [BTF_KIND_FLOAT] = "FLOAT",
331 [BTF_KIND_DECL_TAG] = "DECL_TAG",
332 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
333 [BTF_KIND_ENUM64] = "ENUM64",
334};
335
336const char *btf_type_str(const struct btf_type *t)
337{
338 return btf_kind_str[BTF_INFO_KIND(t->info)];
339}
340
341/* Chunk size we use in safe copy of data to be shown. */
342#define BTF_SHOW_OBJ_SAFE_SIZE 32
343
344/*
345 * This is the maximum size of a base type value (equivalent to a
346 * 128-bit int); if we are at the end of our safe buffer and have
347 * less than 16 bytes space we can't be assured of being able
348 * to copy the next type safely, so in such cases we will initiate
349 * a new copy.
350 */
351#define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
352
353/* Type name size */
354#define BTF_SHOW_NAME_SIZE 80
355
356/*
357 * The suffix of a type that indicates it cannot alias another type when
358 * comparing BTF IDs for kfunc invocations.
359 */
360#define NOCAST_ALIAS_SUFFIX "___init"
361
362/*
363 * Common data to all BTF show operations. Private show functions can add
364 * their own data to a structure containing a struct btf_show and consult it
365 * in the show callback. See btf_type_show() below.
366 *
367 * One challenge with showing nested data is we want to skip 0-valued
368 * data, but in order to figure out whether a nested object is all zeros
369 * we need to walk through it. As a result, we need to make two passes
370 * when handling structs, unions and arrays; the first path simply looks
371 * for nonzero data, while the second actually does the display. The first
372 * pass is signalled by show->state.depth_check being set, and if we
373 * encounter a non-zero value we set show->state.depth_to_show to
374 * the depth at which we encountered it. When we have completed the
375 * first pass, we will know if anything needs to be displayed if
376 * depth_to_show > depth. See btf_[struct,array]_show() for the
377 * implementation of this.
378 *
379 * Another problem is we want to ensure the data for display is safe to
380 * access. To support this, the anonymous "struct {} obj" tracks the data
381 * object and our safe copy of it. We copy portions of the data needed
382 * to the object "copy" buffer, but because its size is limited to
383 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
384 * traverse larger objects for display.
385 *
386 * The various data type show functions all start with a call to
387 * btf_show_start_type() which returns a pointer to the safe copy
388 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
389 * raw data itself). btf_show_obj_safe() is responsible for
390 * using copy_from_kernel_nofault() to update the safe data if necessary
391 * as we traverse the object's data. skbuff-like semantics are
392 * used:
393 *
394 * - obj.head points to the start of the toplevel object for display
395 * - obj.size is the size of the toplevel object
396 * - obj.data points to the current point in the original data at
397 * which our safe data starts. obj.data will advance as we copy
398 * portions of the data.
399 *
400 * In most cases a single copy will suffice, but larger data structures
401 * such as "struct task_struct" will require many copies. The logic in
402 * btf_show_obj_safe() handles the logic that determines if a new
403 * copy_from_kernel_nofault() is needed.
404 */
405struct btf_show {
406 u64 flags;
407 void *target; /* target of show operation (seq file, buffer) */
408 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
409 const struct btf *btf;
410 /* below are used during iteration */
411 struct {
412 u8 depth;
413 u8 depth_to_show;
414 u8 depth_check;
415 u8 array_member:1,
416 array_terminated:1;
417 u16 array_encoding;
418 u32 type_id;
419 int status; /* non-zero for error */
420 const struct btf_type *type;
421 const struct btf_member *member;
422 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
423 } state;
424 struct {
425 u32 size;
426 void *head;
427 void *data;
428 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
429 } obj;
430};
431
432struct btf_kind_operations {
433 s32 (*check_meta)(struct btf_verifier_env *env,
434 const struct btf_type *t,
435 u32 meta_left);
436 int (*resolve)(struct btf_verifier_env *env,
437 const struct resolve_vertex *v);
438 int (*check_member)(struct btf_verifier_env *env,
439 const struct btf_type *struct_type,
440 const struct btf_member *member,
441 const struct btf_type *member_type);
442 int (*check_kflag_member)(struct btf_verifier_env *env,
443 const struct btf_type *struct_type,
444 const struct btf_member *member,
445 const struct btf_type *member_type);
446 void (*log_details)(struct btf_verifier_env *env,
447 const struct btf_type *t);
448 void (*show)(const struct btf *btf, const struct btf_type *t,
449 u32 type_id, void *data, u8 bits_offsets,
450 struct btf_show *show);
451};
452
453static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
454static struct btf_type btf_void;
455
456static int btf_resolve(struct btf_verifier_env *env,
457 const struct btf_type *t, u32 type_id);
458
459static int btf_func_check(struct btf_verifier_env *env,
460 const struct btf_type *t);
461
462static bool btf_type_is_modifier(const struct btf_type *t)
463{
464 /* Some of them is not strictly a C modifier
465 * but they are grouped into the same bucket
466 * for BTF concern:
467 * A type (t) that refers to another
468 * type through t->type AND its size cannot
469 * be determined without following the t->type.
470 *
471 * ptr does not fall into this bucket
472 * because its size is always sizeof(void *).
473 */
474 switch (BTF_INFO_KIND(t->info)) {
475 case BTF_KIND_TYPEDEF:
476 case BTF_KIND_VOLATILE:
477 case BTF_KIND_CONST:
478 case BTF_KIND_RESTRICT:
479 case BTF_KIND_TYPE_TAG:
480 return true;
481 }
482
483 return false;
484}
485
486bool btf_type_is_void(const struct btf_type *t)
487{
488 return t == &btf_void;
489}
490
491static bool btf_type_is_fwd(const struct btf_type *t)
492{
493 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
494}
495
496static bool btf_type_is_datasec(const struct btf_type *t)
497{
498 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
499}
500
501static bool btf_type_is_decl_tag(const struct btf_type *t)
502{
503 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
504}
505
506static bool btf_type_nosize(const struct btf_type *t)
507{
508 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
509 btf_type_is_func(t) || btf_type_is_func_proto(t) ||
510 btf_type_is_decl_tag(t);
511}
512
513static bool btf_type_nosize_or_null(const struct btf_type *t)
514{
515 return !t || btf_type_nosize(t);
516}
517
518static bool btf_type_is_decl_tag_target(const struct btf_type *t)
519{
520 return btf_type_is_func(t) || btf_type_is_struct(t) ||
521 btf_type_is_var(t) || btf_type_is_typedef(t);
522}
523
524u32 btf_nr_types(const struct btf *btf)
525{
526 u32 total = 0;
527
528 while (btf) {
529 total += btf->nr_types;
530 btf = btf->base_btf;
531 }
532
533 return total;
534}
535
536s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
537{
538 const struct btf_type *t;
539 const char *tname;
540 u32 i, total;
541
542 total = btf_nr_types(btf);
543 for (i = 1; i < total; i++) {
544 t = btf_type_by_id(btf, i);
545 if (BTF_INFO_KIND(t->info) != kind)
546 continue;
547
548 tname = btf_name_by_offset(btf, t->name_off);
549 if (!strcmp(tname, name))
550 return i;
551 }
552
553 return -ENOENT;
554}
555
556s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
557{
558 struct btf *btf;
559 s32 ret;
560 int id;
561
562 btf = bpf_get_btf_vmlinux();
563 if (IS_ERR(btf))
564 return PTR_ERR(btf);
565 if (!btf)
566 return -EINVAL;
567
568 ret = btf_find_by_name_kind(btf, name, kind);
569 /* ret is never zero, since btf_find_by_name_kind returns
570 * positive btf_id or negative error.
571 */
572 if (ret > 0) {
573 btf_get(btf);
574 *btf_p = btf;
575 return ret;
576 }
577
578 /* If name is not found in vmlinux's BTF then search in module's BTFs */
579 spin_lock_bh(&btf_idr_lock);
580 idr_for_each_entry(&btf_idr, btf, id) {
581 if (!btf_is_module(btf))
582 continue;
583 /* linear search could be slow hence unlock/lock
584 * the IDR to avoiding holding it for too long
585 */
586 btf_get(btf);
587 spin_unlock_bh(&btf_idr_lock);
588 ret = btf_find_by_name_kind(btf, name, kind);
589 if (ret > 0) {
590 *btf_p = btf;
591 return ret;
592 }
593 btf_put(btf);
594 spin_lock_bh(&btf_idr_lock);
595 }
596 spin_unlock_bh(&btf_idr_lock);
597 return ret;
598}
599
600const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
601 u32 id, u32 *res_id)
602{
603 const struct btf_type *t = btf_type_by_id(btf, id);
604
605 while (btf_type_is_modifier(t)) {
606 id = t->type;
607 t = btf_type_by_id(btf, t->type);
608 }
609
610 if (res_id)
611 *res_id = id;
612
613 return t;
614}
615
616const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
617 u32 id, u32 *res_id)
618{
619 const struct btf_type *t;
620
621 t = btf_type_skip_modifiers(btf, id, NULL);
622 if (!btf_type_is_ptr(t))
623 return NULL;
624
625 return btf_type_skip_modifiers(btf, t->type, res_id);
626}
627
628const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
629 u32 id, u32 *res_id)
630{
631 const struct btf_type *ptype;
632
633 ptype = btf_type_resolve_ptr(btf, id, res_id);
634 if (ptype && btf_type_is_func_proto(ptype))
635 return ptype;
636
637 return NULL;
638}
639
640/* Types that act only as a source, not sink or intermediate
641 * type when resolving.
642 */
643static bool btf_type_is_resolve_source_only(const struct btf_type *t)
644{
645 return btf_type_is_var(t) ||
646 btf_type_is_decl_tag(t) ||
647 btf_type_is_datasec(t);
648}
649
650/* What types need to be resolved?
651 *
652 * btf_type_is_modifier() is an obvious one.
653 *
654 * btf_type_is_struct() because its member refers to
655 * another type (through member->type).
656 *
657 * btf_type_is_var() because the variable refers to
658 * another type. btf_type_is_datasec() holds multiple
659 * btf_type_is_var() types that need resolving.
660 *
661 * btf_type_is_array() because its element (array->type)
662 * refers to another type. Array can be thought of a
663 * special case of struct while array just has the same
664 * member-type repeated by array->nelems of times.
665 */
666static bool btf_type_needs_resolve(const struct btf_type *t)
667{
668 return btf_type_is_modifier(t) ||
669 btf_type_is_ptr(t) ||
670 btf_type_is_struct(t) ||
671 btf_type_is_array(t) ||
672 btf_type_is_var(t) ||
673 btf_type_is_func(t) ||
674 btf_type_is_decl_tag(t) ||
675 btf_type_is_datasec(t);
676}
677
678/* t->size can be used */
679static bool btf_type_has_size(const struct btf_type *t)
680{
681 switch (BTF_INFO_KIND(t->info)) {
682 case BTF_KIND_INT:
683 case BTF_KIND_STRUCT:
684 case BTF_KIND_UNION:
685 case BTF_KIND_ENUM:
686 case BTF_KIND_DATASEC:
687 case BTF_KIND_FLOAT:
688 case BTF_KIND_ENUM64:
689 return true;
690 }
691
692 return false;
693}
694
695static const char *btf_int_encoding_str(u8 encoding)
696{
697 if (encoding == 0)
698 return "(none)";
699 else if (encoding == BTF_INT_SIGNED)
700 return "SIGNED";
701 else if (encoding == BTF_INT_CHAR)
702 return "CHAR";
703 else if (encoding == BTF_INT_BOOL)
704 return "BOOL";
705 else
706 return "UNKN";
707}
708
709static u32 btf_type_int(const struct btf_type *t)
710{
711 return *(u32 *)(t + 1);
712}
713
714static const struct btf_array *btf_type_array(const struct btf_type *t)
715{
716 return (const struct btf_array *)(t + 1);
717}
718
719static const struct btf_enum *btf_type_enum(const struct btf_type *t)
720{
721 return (const struct btf_enum *)(t + 1);
722}
723
724static const struct btf_var *btf_type_var(const struct btf_type *t)
725{
726 return (const struct btf_var *)(t + 1);
727}
728
729static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
730{
731 return (const struct btf_decl_tag *)(t + 1);
732}
733
734static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
735{
736 return (const struct btf_enum64 *)(t + 1);
737}
738
739static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
740{
741 return kind_ops[BTF_INFO_KIND(t->info)];
742}
743
744static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
745{
746 if (!BTF_STR_OFFSET_VALID(offset))
747 return false;
748
749 while (offset < btf->start_str_off)
750 btf = btf->base_btf;
751
752 offset -= btf->start_str_off;
753 return offset < btf->hdr.str_len;
754}
755
756static bool __btf_name_char_ok(char c, bool first)
757{
758 if ((first ? !isalpha(c) :
759 !isalnum(c)) &&
760 c != '_' &&
761 c != '.')
762 return false;
763 return true;
764}
765
766static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
767{
768 while (offset < btf->start_str_off)
769 btf = btf->base_btf;
770
771 offset -= btf->start_str_off;
772 if (offset < btf->hdr.str_len)
773 return &btf->strings[offset];
774
775 return NULL;
776}
777
778static bool __btf_name_valid(const struct btf *btf, u32 offset)
779{
780 /* offset must be valid */
781 const char *src = btf_str_by_offset(btf, offset);
782 const char *src_limit;
783
784 if (!__btf_name_char_ok(*src, true))
785 return false;
786
787 /* set a limit on identifier length */
788 src_limit = src + KSYM_NAME_LEN;
789 src++;
790 while (*src && src < src_limit) {
791 if (!__btf_name_char_ok(*src, false))
792 return false;
793 src++;
794 }
795
796 return !*src;
797}
798
799static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
800{
801 return __btf_name_valid(btf, offset);
802}
803
804static bool btf_name_valid_section(const struct btf *btf, u32 offset)
805{
806 return __btf_name_valid(btf, offset);
807}
808
809static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
810{
811 const char *name;
812
813 if (!offset)
814 return "(anon)";
815
816 name = btf_str_by_offset(btf, offset);
817 return name ?: "(invalid-name-offset)";
818}
819
820const char *btf_name_by_offset(const struct btf *btf, u32 offset)
821{
822 return btf_str_by_offset(btf, offset);
823}
824
825const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
826{
827 while (type_id < btf->start_id)
828 btf = btf->base_btf;
829
830 type_id -= btf->start_id;
831 if (type_id >= btf->nr_types)
832 return NULL;
833 return btf->types[type_id];
834}
835EXPORT_SYMBOL_GPL(btf_type_by_id);
836
837/*
838 * Regular int is not a bit field and it must be either
839 * u8/u16/u32/u64 or __int128.
840 */
841static bool btf_type_int_is_regular(const struct btf_type *t)
842{
843 u8 nr_bits, nr_bytes;
844 u32 int_data;
845
846 int_data = btf_type_int(t);
847 nr_bits = BTF_INT_BITS(int_data);
848 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
849 if (BITS_PER_BYTE_MASKED(nr_bits) ||
850 BTF_INT_OFFSET(int_data) ||
851 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
852 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
853 nr_bytes != (2 * sizeof(u64)))) {
854 return false;
855 }
856
857 return true;
858}
859
860/*
861 * Check that given struct member is a regular int with expected
862 * offset and size.
863 */
864bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
865 const struct btf_member *m,
866 u32 expected_offset, u32 expected_size)
867{
868 const struct btf_type *t;
869 u32 id, int_data;
870 u8 nr_bits;
871
872 id = m->type;
873 t = btf_type_id_size(btf, &id, NULL);
874 if (!t || !btf_type_is_int(t))
875 return false;
876
877 int_data = btf_type_int(t);
878 nr_bits = BTF_INT_BITS(int_data);
879 if (btf_type_kflag(s)) {
880 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
881 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
882
883 /* if kflag set, int should be a regular int and
884 * bit offset should be at byte boundary.
885 */
886 return !bitfield_size &&
887 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
888 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
889 }
890
891 if (BTF_INT_OFFSET(int_data) ||
892 BITS_PER_BYTE_MASKED(m->offset) ||
893 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
894 BITS_PER_BYTE_MASKED(nr_bits) ||
895 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
896 return false;
897
898 return true;
899}
900
901/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
902static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
903 u32 id)
904{
905 const struct btf_type *t = btf_type_by_id(btf, id);
906
907 while (btf_type_is_modifier(t) &&
908 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
909 t = btf_type_by_id(btf, t->type);
910 }
911
912 return t;
913}
914
915#define BTF_SHOW_MAX_ITER 10
916
917#define BTF_KIND_BIT(kind) (1ULL << kind)
918
919/*
920 * Populate show->state.name with type name information.
921 * Format of type name is
922 *
923 * [.member_name = ] (type_name)
924 */
925static const char *btf_show_name(struct btf_show *show)
926{
927 /* BTF_MAX_ITER array suffixes "[]" */
928 const char *array_suffixes = "[][][][][][][][][][]";
929 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
930 /* BTF_MAX_ITER pointer suffixes "*" */
931 const char *ptr_suffixes = "**********";
932 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
933 const char *name = NULL, *prefix = "", *parens = "";
934 const struct btf_member *m = show->state.member;
935 const struct btf_type *t;
936 const struct btf_array *array;
937 u32 id = show->state.type_id;
938 const char *member = NULL;
939 bool show_member = false;
940 u64 kinds = 0;
941 int i;
942
943 show->state.name[0] = '\0';
944
945 /*
946 * Don't show type name if we're showing an array member;
947 * in that case we show the array type so don't need to repeat
948 * ourselves for each member.
949 */
950 if (show->state.array_member)
951 return "";
952
953 /* Retrieve member name, if any. */
954 if (m) {
955 member = btf_name_by_offset(show->btf, m->name_off);
956 show_member = strlen(member) > 0;
957 id = m->type;
958 }
959
960 /*
961 * Start with type_id, as we have resolved the struct btf_type *
962 * via btf_modifier_show() past the parent typedef to the child
963 * struct, int etc it is defined as. In such cases, the type_id
964 * still represents the starting type while the struct btf_type *
965 * in our show->state points at the resolved type of the typedef.
966 */
967 t = btf_type_by_id(show->btf, id);
968 if (!t)
969 return "";
970
971 /*
972 * The goal here is to build up the right number of pointer and
973 * array suffixes while ensuring the type name for a typedef
974 * is represented. Along the way we accumulate a list of
975 * BTF kinds we have encountered, since these will inform later
976 * display; for example, pointer types will not require an
977 * opening "{" for struct, we will just display the pointer value.
978 *
979 * We also want to accumulate the right number of pointer or array
980 * indices in the format string while iterating until we get to
981 * the typedef/pointee/array member target type.
982 *
983 * We start by pointing at the end of pointer and array suffix
984 * strings; as we accumulate pointers and arrays we move the pointer
985 * or array string backwards so it will show the expected number of
986 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
987 * and/or arrays and typedefs are supported as a precaution.
988 *
989 * We also want to get typedef name while proceeding to resolve
990 * type it points to so that we can add parentheses if it is a
991 * "typedef struct" etc.
992 */
993 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
994
995 switch (BTF_INFO_KIND(t->info)) {
996 case BTF_KIND_TYPEDEF:
997 if (!name)
998 name = btf_name_by_offset(show->btf,
999 t->name_off);
1000 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
1001 id = t->type;
1002 break;
1003 case BTF_KIND_ARRAY:
1004 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
1005 parens = "[";
1006 if (!t)
1007 return "";
1008 array = btf_type_array(t);
1009 if (array_suffix > array_suffixes)
1010 array_suffix -= 2;
1011 id = array->type;
1012 break;
1013 case BTF_KIND_PTR:
1014 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
1015 if (ptr_suffix > ptr_suffixes)
1016 ptr_suffix -= 1;
1017 id = t->type;
1018 break;
1019 default:
1020 id = 0;
1021 break;
1022 }
1023 if (!id)
1024 break;
1025 t = btf_type_skip_qualifiers(show->btf, id);
1026 }
1027 /* We may not be able to represent this type; bail to be safe */
1028 if (i == BTF_SHOW_MAX_ITER)
1029 return "";
1030
1031 if (!name)
1032 name = btf_name_by_offset(show->btf, t->name_off);
1033
1034 switch (BTF_INFO_KIND(t->info)) {
1035 case BTF_KIND_STRUCT:
1036 case BTF_KIND_UNION:
1037 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1038 "struct" : "union";
1039 /* if it's an array of struct/union, parens is already set */
1040 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1041 parens = "{";
1042 break;
1043 case BTF_KIND_ENUM:
1044 case BTF_KIND_ENUM64:
1045 prefix = "enum";
1046 break;
1047 default:
1048 break;
1049 }
1050
1051 /* pointer does not require parens */
1052 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1053 parens = "";
1054 /* typedef does not require struct/union/enum prefix */
1055 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1056 prefix = "";
1057
1058 if (!name)
1059 name = "";
1060
1061 /* Even if we don't want type name info, we want parentheses etc */
1062 if (show->flags & BTF_SHOW_NONAME)
1063 snprintf(show->state.name, sizeof(show->state.name), "%s",
1064 parens);
1065 else
1066 snprintf(show->state.name, sizeof(show->state.name),
1067 "%s%s%s(%s%s%s%s%s%s)%s",
1068 /* first 3 strings comprise ".member = " */
1069 show_member ? "." : "",
1070 show_member ? member : "",
1071 show_member ? " = " : "",
1072 /* ...next is our prefix (struct, enum, etc) */
1073 prefix,
1074 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1075 /* ...this is the type name itself */
1076 name,
1077 /* ...suffixed by the appropriate '*', '[]' suffixes */
1078 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1079 array_suffix, parens);
1080
1081 return show->state.name;
1082}
1083
1084static const char *__btf_show_indent(struct btf_show *show)
1085{
1086 const char *indents = " ";
1087 const char *indent = &indents[strlen(indents)];
1088
1089 if ((indent - show->state.depth) >= indents)
1090 return indent - show->state.depth;
1091 return indents;
1092}
1093
1094static const char *btf_show_indent(struct btf_show *show)
1095{
1096 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1097}
1098
1099static const char *btf_show_newline(struct btf_show *show)
1100{
1101 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1102}
1103
1104static const char *btf_show_delim(struct btf_show *show)
1105{
1106 if (show->state.depth == 0)
1107 return "";
1108
1109 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1110 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1111 return "|";
1112
1113 return ",";
1114}
1115
1116__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1117{
1118 va_list args;
1119
1120 if (!show->state.depth_check) {
1121 va_start(args, fmt);
1122 show->showfn(show, fmt, args);
1123 va_end(args);
1124 }
1125}
1126
1127/* Macros are used here as btf_show_type_value[s]() prepends and appends
1128 * format specifiers to the format specifier passed in; these do the work of
1129 * adding indentation, delimiters etc while the caller simply has to specify
1130 * the type value(s) in the format specifier + value(s).
1131 */
1132#define btf_show_type_value(show, fmt, value) \
1133 do { \
1134 if ((value) != (__typeof__(value))0 || \
1135 (show->flags & BTF_SHOW_ZERO) || \
1136 show->state.depth == 0) { \
1137 btf_show(show, "%s%s" fmt "%s%s", \
1138 btf_show_indent(show), \
1139 btf_show_name(show), \
1140 value, btf_show_delim(show), \
1141 btf_show_newline(show)); \
1142 if (show->state.depth > show->state.depth_to_show) \
1143 show->state.depth_to_show = show->state.depth; \
1144 } \
1145 } while (0)
1146
1147#define btf_show_type_values(show, fmt, ...) \
1148 do { \
1149 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1150 btf_show_name(show), \
1151 __VA_ARGS__, btf_show_delim(show), \
1152 btf_show_newline(show)); \
1153 if (show->state.depth > show->state.depth_to_show) \
1154 show->state.depth_to_show = show->state.depth; \
1155 } while (0)
1156
1157/* How much is left to copy to safe buffer after @data? */
1158static int btf_show_obj_size_left(struct btf_show *show, void *data)
1159{
1160 return show->obj.head + show->obj.size - data;
1161}
1162
1163/* Is object pointed to by @data of @size already copied to our safe buffer? */
1164static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1165{
1166 return data >= show->obj.data &&
1167 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1168}
1169
1170/*
1171 * If object pointed to by @data of @size falls within our safe buffer, return
1172 * the equivalent pointer to the same safe data. Assumes
1173 * copy_from_kernel_nofault() has already happened and our safe buffer is
1174 * populated.
1175 */
1176static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1177{
1178 if (btf_show_obj_is_safe(show, data, size))
1179 return show->obj.safe + (data - show->obj.data);
1180 return NULL;
1181}
1182
1183/*
1184 * Return a safe-to-access version of data pointed to by @data.
1185 * We do this by copying the relevant amount of information
1186 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1187 *
1188 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1189 * safe copy is needed.
1190 *
1191 * Otherwise we need to determine if we have the required amount
1192 * of data (determined by the @data pointer and the size of the
1193 * largest base type we can encounter (represented by
1194 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1195 * that we will be able to print some of the current object,
1196 * and if more is needed a copy will be triggered.
1197 * Some objects such as structs will not fit into the buffer;
1198 * in such cases additional copies when we iterate over their
1199 * members may be needed.
1200 *
1201 * btf_show_obj_safe() is used to return a safe buffer for
1202 * btf_show_start_type(); this ensures that as we recurse into
1203 * nested types we always have safe data for the given type.
1204 * This approach is somewhat wasteful; it's possible for example
1205 * that when iterating over a large union we'll end up copying the
1206 * same data repeatedly, but the goal is safety not performance.
1207 * We use stack data as opposed to per-CPU buffers because the
1208 * iteration over a type can take some time, and preemption handling
1209 * would greatly complicate use of the safe buffer.
1210 */
1211static void *btf_show_obj_safe(struct btf_show *show,
1212 const struct btf_type *t,
1213 void *data)
1214{
1215 const struct btf_type *rt;
1216 int size_left, size;
1217 void *safe = NULL;
1218
1219 if (show->flags & BTF_SHOW_UNSAFE)
1220 return data;
1221
1222 rt = btf_resolve_size(show->btf, t, &size);
1223 if (IS_ERR(rt)) {
1224 show->state.status = PTR_ERR(rt);
1225 return NULL;
1226 }
1227
1228 /*
1229 * Is this toplevel object? If so, set total object size and
1230 * initialize pointers. Otherwise check if we still fall within
1231 * our safe object data.
1232 */
1233 if (show->state.depth == 0) {
1234 show->obj.size = size;
1235 show->obj.head = data;
1236 } else {
1237 /*
1238 * If the size of the current object is > our remaining
1239 * safe buffer we _may_ need to do a new copy. However
1240 * consider the case of a nested struct; it's size pushes
1241 * us over the safe buffer limit, but showing any individual
1242 * struct members does not. In such cases, we don't need
1243 * to initiate a fresh copy yet; however we definitely need
1244 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1245 * in our buffer, regardless of the current object size.
1246 * The logic here is that as we resolve types we will
1247 * hit a base type at some point, and we need to be sure
1248 * the next chunk of data is safely available to display
1249 * that type info safely. We cannot rely on the size of
1250 * the current object here because it may be much larger
1251 * than our current buffer (e.g. task_struct is 8k).
1252 * All we want to do here is ensure that we can print the
1253 * next basic type, which we can if either
1254 * - the current type size is within the safe buffer; or
1255 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1256 * the safe buffer.
1257 */
1258 safe = __btf_show_obj_safe(show, data,
1259 min(size,
1260 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1261 }
1262
1263 /*
1264 * We need a new copy to our safe object, either because we haven't
1265 * yet copied and are initializing safe data, or because the data
1266 * we want falls outside the boundaries of the safe object.
1267 */
1268 if (!safe) {
1269 size_left = btf_show_obj_size_left(show, data);
1270 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1271 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1272 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1273 data, size_left);
1274 if (!show->state.status) {
1275 show->obj.data = data;
1276 safe = show->obj.safe;
1277 }
1278 }
1279
1280 return safe;
1281}
1282
1283/*
1284 * Set the type we are starting to show and return a safe data pointer
1285 * to be used for showing the associated data.
1286 */
1287static void *btf_show_start_type(struct btf_show *show,
1288 const struct btf_type *t,
1289 u32 type_id, void *data)
1290{
1291 show->state.type = t;
1292 show->state.type_id = type_id;
1293 show->state.name[0] = '\0';
1294
1295 return btf_show_obj_safe(show, t, data);
1296}
1297
1298static void btf_show_end_type(struct btf_show *show)
1299{
1300 show->state.type = NULL;
1301 show->state.type_id = 0;
1302 show->state.name[0] = '\0';
1303}
1304
1305static void *btf_show_start_aggr_type(struct btf_show *show,
1306 const struct btf_type *t,
1307 u32 type_id, void *data)
1308{
1309 void *safe_data = btf_show_start_type(show, t, type_id, data);
1310
1311 if (!safe_data)
1312 return safe_data;
1313
1314 btf_show(show, "%s%s%s", btf_show_indent(show),
1315 btf_show_name(show),
1316 btf_show_newline(show));
1317 show->state.depth++;
1318 return safe_data;
1319}
1320
1321static void btf_show_end_aggr_type(struct btf_show *show,
1322 const char *suffix)
1323{
1324 show->state.depth--;
1325 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1326 btf_show_delim(show), btf_show_newline(show));
1327 btf_show_end_type(show);
1328}
1329
1330static void btf_show_start_member(struct btf_show *show,
1331 const struct btf_member *m)
1332{
1333 show->state.member = m;
1334}
1335
1336static void btf_show_start_array_member(struct btf_show *show)
1337{
1338 show->state.array_member = 1;
1339 btf_show_start_member(show, NULL);
1340}
1341
1342static void btf_show_end_member(struct btf_show *show)
1343{
1344 show->state.member = NULL;
1345}
1346
1347static void btf_show_end_array_member(struct btf_show *show)
1348{
1349 show->state.array_member = 0;
1350 btf_show_end_member(show);
1351}
1352
1353static void *btf_show_start_array_type(struct btf_show *show,
1354 const struct btf_type *t,
1355 u32 type_id,
1356 u16 array_encoding,
1357 void *data)
1358{
1359 show->state.array_encoding = array_encoding;
1360 show->state.array_terminated = 0;
1361 return btf_show_start_aggr_type(show, t, type_id, data);
1362}
1363
1364static void btf_show_end_array_type(struct btf_show *show)
1365{
1366 show->state.array_encoding = 0;
1367 show->state.array_terminated = 0;
1368 btf_show_end_aggr_type(show, "]");
1369}
1370
1371static void *btf_show_start_struct_type(struct btf_show *show,
1372 const struct btf_type *t,
1373 u32 type_id,
1374 void *data)
1375{
1376 return btf_show_start_aggr_type(show, t, type_id, data);
1377}
1378
1379static void btf_show_end_struct_type(struct btf_show *show)
1380{
1381 btf_show_end_aggr_type(show, "}");
1382}
1383
1384__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1385 const char *fmt, ...)
1386{
1387 va_list args;
1388
1389 va_start(args, fmt);
1390 bpf_verifier_vlog(log, fmt, args);
1391 va_end(args);
1392}
1393
1394__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1395 const char *fmt, ...)
1396{
1397 struct bpf_verifier_log *log = &env->log;
1398 va_list args;
1399
1400 if (!bpf_verifier_log_needed(log))
1401 return;
1402
1403 va_start(args, fmt);
1404 bpf_verifier_vlog(log, fmt, args);
1405 va_end(args);
1406}
1407
1408__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1409 const struct btf_type *t,
1410 bool log_details,
1411 const char *fmt, ...)
1412{
1413 struct bpf_verifier_log *log = &env->log;
1414 struct btf *btf = env->btf;
1415 va_list args;
1416
1417 if (!bpf_verifier_log_needed(log))
1418 return;
1419
1420 if (log->level == BPF_LOG_KERNEL) {
1421 /* btf verifier prints all types it is processing via
1422 * btf_verifier_log_type(..., fmt = NULL).
1423 * Skip those prints for in-kernel BTF verification.
1424 */
1425 if (!fmt)
1426 return;
1427
1428 /* Skip logging when loading module BTF with mismatches permitted */
1429 if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1430 return;
1431 }
1432
1433 __btf_verifier_log(log, "[%u] %s %s%s",
1434 env->log_type_id,
1435 btf_type_str(t),
1436 __btf_name_by_offset(btf, t->name_off),
1437 log_details ? " " : "");
1438
1439 if (log_details)
1440 btf_type_ops(t)->log_details(env, t);
1441
1442 if (fmt && *fmt) {
1443 __btf_verifier_log(log, " ");
1444 va_start(args, fmt);
1445 bpf_verifier_vlog(log, fmt, args);
1446 va_end(args);
1447 }
1448
1449 __btf_verifier_log(log, "\n");
1450}
1451
1452#define btf_verifier_log_type(env, t, ...) \
1453 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1454#define btf_verifier_log_basic(env, t, ...) \
1455 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1456
1457__printf(4, 5)
1458static void btf_verifier_log_member(struct btf_verifier_env *env,
1459 const struct btf_type *struct_type,
1460 const struct btf_member *member,
1461 const char *fmt, ...)
1462{
1463 struct bpf_verifier_log *log = &env->log;
1464 struct btf *btf = env->btf;
1465 va_list args;
1466
1467 if (!bpf_verifier_log_needed(log))
1468 return;
1469
1470 if (log->level == BPF_LOG_KERNEL) {
1471 if (!fmt)
1472 return;
1473
1474 /* Skip logging when loading module BTF with mismatches permitted */
1475 if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1476 return;
1477 }
1478
1479 /* The CHECK_META phase already did a btf dump.
1480 *
1481 * If member is logged again, it must hit an error in
1482 * parsing this member. It is useful to print out which
1483 * struct this member belongs to.
1484 */
1485 if (env->phase != CHECK_META)
1486 btf_verifier_log_type(env, struct_type, NULL);
1487
1488 if (btf_type_kflag(struct_type))
1489 __btf_verifier_log(log,
1490 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1491 __btf_name_by_offset(btf, member->name_off),
1492 member->type,
1493 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1494 BTF_MEMBER_BIT_OFFSET(member->offset));
1495 else
1496 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1497 __btf_name_by_offset(btf, member->name_off),
1498 member->type, member->offset);
1499
1500 if (fmt && *fmt) {
1501 __btf_verifier_log(log, " ");
1502 va_start(args, fmt);
1503 bpf_verifier_vlog(log, fmt, args);
1504 va_end(args);
1505 }
1506
1507 __btf_verifier_log(log, "\n");
1508}
1509
1510__printf(4, 5)
1511static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1512 const struct btf_type *datasec_type,
1513 const struct btf_var_secinfo *vsi,
1514 const char *fmt, ...)
1515{
1516 struct bpf_verifier_log *log = &env->log;
1517 va_list args;
1518
1519 if (!bpf_verifier_log_needed(log))
1520 return;
1521 if (log->level == BPF_LOG_KERNEL && !fmt)
1522 return;
1523 if (env->phase != CHECK_META)
1524 btf_verifier_log_type(env, datasec_type, NULL);
1525
1526 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1527 vsi->type, vsi->offset, vsi->size);
1528 if (fmt && *fmt) {
1529 __btf_verifier_log(log, " ");
1530 va_start(args, fmt);
1531 bpf_verifier_vlog(log, fmt, args);
1532 va_end(args);
1533 }
1534
1535 __btf_verifier_log(log, "\n");
1536}
1537
1538static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1539 u32 btf_data_size)
1540{
1541 struct bpf_verifier_log *log = &env->log;
1542 const struct btf *btf = env->btf;
1543 const struct btf_header *hdr;
1544
1545 if (!bpf_verifier_log_needed(log))
1546 return;
1547
1548 if (log->level == BPF_LOG_KERNEL)
1549 return;
1550 hdr = &btf->hdr;
1551 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1552 __btf_verifier_log(log, "version: %u\n", hdr->version);
1553 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1554 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1555 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1556 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1557 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1558 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1559 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1560}
1561
1562static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1563{
1564 struct btf *btf = env->btf;
1565
1566 if (btf->types_size == btf->nr_types) {
1567 /* Expand 'types' array */
1568
1569 struct btf_type **new_types;
1570 u32 expand_by, new_size;
1571
1572 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1573 btf_verifier_log(env, "Exceeded max num of types");
1574 return -E2BIG;
1575 }
1576
1577 expand_by = max_t(u32, btf->types_size >> 2, 16);
1578 new_size = min_t(u32, BTF_MAX_TYPE,
1579 btf->types_size + expand_by);
1580
1581 new_types = kvcalloc(new_size, sizeof(*new_types),
1582 GFP_KERNEL | __GFP_NOWARN);
1583 if (!new_types)
1584 return -ENOMEM;
1585
1586 if (btf->nr_types == 0) {
1587 if (!btf->base_btf) {
1588 /* lazily init VOID type */
1589 new_types[0] = &btf_void;
1590 btf->nr_types++;
1591 }
1592 } else {
1593 memcpy(new_types, btf->types,
1594 sizeof(*btf->types) * btf->nr_types);
1595 }
1596
1597 kvfree(btf->types);
1598 btf->types = new_types;
1599 btf->types_size = new_size;
1600 }
1601
1602 btf->types[btf->nr_types++] = t;
1603
1604 return 0;
1605}
1606
1607static int btf_alloc_id(struct btf *btf)
1608{
1609 int id;
1610
1611 idr_preload(GFP_KERNEL);
1612 spin_lock_bh(&btf_idr_lock);
1613 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1614 if (id > 0)
1615 btf->id = id;
1616 spin_unlock_bh(&btf_idr_lock);
1617 idr_preload_end();
1618
1619 if (WARN_ON_ONCE(!id))
1620 return -ENOSPC;
1621
1622 return id > 0 ? 0 : id;
1623}
1624
1625static void btf_free_id(struct btf *btf)
1626{
1627 unsigned long flags;
1628
1629 /*
1630 * In map-in-map, calling map_delete_elem() on outer
1631 * map will call bpf_map_put on the inner map.
1632 * It will then eventually call btf_free_id()
1633 * on the inner map. Some of the map_delete_elem()
1634 * implementation may have irq disabled, so
1635 * we need to use the _irqsave() version instead
1636 * of the _bh() version.
1637 */
1638 spin_lock_irqsave(&btf_idr_lock, flags);
1639 idr_remove(&btf_idr, btf->id);
1640 spin_unlock_irqrestore(&btf_idr_lock, flags);
1641}
1642
1643static void btf_free_kfunc_set_tab(struct btf *btf)
1644{
1645 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1646 int hook;
1647
1648 if (!tab)
1649 return;
1650 /* For module BTF, we directly assign the sets being registered, so
1651 * there is nothing to free except kfunc_set_tab.
1652 */
1653 if (btf_is_module(btf))
1654 goto free_tab;
1655 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1656 kfree(tab->sets[hook]);
1657free_tab:
1658 kfree(tab);
1659 btf->kfunc_set_tab = NULL;
1660}
1661
1662static void btf_free_dtor_kfunc_tab(struct btf *btf)
1663{
1664 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1665
1666 if (!tab)
1667 return;
1668 kfree(tab);
1669 btf->dtor_kfunc_tab = NULL;
1670}
1671
1672static void btf_struct_metas_free(struct btf_struct_metas *tab)
1673{
1674 int i;
1675
1676 if (!tab)
1677 return;
1678 for (i = 0; i < tab->cnt; i++)
1679 btf_record_free(tab->types[i].record);
1680 kfree(tab);
1681}
1682
1683static void btf_free_struct_meta_tab(struct btf *btf)
1684{
1685 struct btf_struct_metas *tab = btf->struct_meta_tab;
1686
1687 btf_struct_metas_free(tab);
1688 btf->struct_meta_tab = NULL;
1689}
1690
1691static void btf_free(struct btf *btf)
1692{
1693 btf_free_struct_meta_tab(btf);
1694 btf_free_dtor_kfunc_tab(btf);
1695 btf_free_kfunc_set_tab(btf);
1696 kvfree(btf->types);
1697 kvfree(btf->resolved_sizes);
1698 kvfree(btf->resolved_ids);
1699 kvfree(btf->data);
1700 kfree(btf);
1701}
1702
1703static void btf_free_rcu(struct rcu_head *rcu)
1704{
1705 struct btf *btf = container_of(rcu, struct btf, rcu);
1706
1707 btf_free(btf);
1708}
1709
1710void btf_get(struct btf *btf)
1711{
1712 refcount_inc(&btf->refcnt);
1713}
1714
1715void btf_put(struct btf *btf)
1716{
1717 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1718 btf_free_id(btf);
1719 call_rcu(&btf->rcu, btf_free_rcu);
1720 }
1721}
1722
1723static int env_resolve_init(struct btf_verifier_env *env)
1724{
1725 struct btf *btf = env->btf;
1726 u32 nr_types = btf->nr_types;
1727 u32 *resolved_sizes = NULL;
1728 u32 *resolved_ids = NULL;
1729 u8 *visit_states = NULL;
1730
1731 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1732 GFP_KERNEL | __GFP_NOWARN);
1733 if (!resolved_sizes)
1734 goto nomem;
1735
1736 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1737 GFP_KERNEL | __GFP_NOWARN);
1738 if (!resolved_ids)
1739 goto nomem;
1740
1741 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1742 GFP_KERNEL | __GFP_NOWARN);
1743 if (!visit_states)
1744 goto nomem;
1745
1746 btf->resolved_sizes = resolved_sizes;
1747 btf->resolved_ids = resolved_ids;
1748 env->visit_states = visit_states;
1749
1750 return 0;
1751
1752nomem:
1753 kvfree(resolved_sizes);
1754 kvfree(resolved_ids);
1755 kvfree(visit_states);
1756 return -ENOMEM;
1757}
1758
1759static void btf_verifier_env_free(struct btf_verifier_env *env)
1760{
1761 kvfree(env->visit_states);
1762 kfree(env);
1763}
1764
1765static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1766 const struct btf_type *next_type)
1767{
1768 switch (env->resolve_mode) {
1769 case RESOLVE_TBD:
1770 /* int, enum or void is a sink */
1771 return !btf_type_needs_resolve(next_type);
1772 case RESOLVE_PTR:
1773 /* int, enum, void, struct, array, func or func_proto is a sink
1774 * for ptr
1775 */
1776 return !btf_type_is_modifier(next_type) &&
1777 !btf_type_is_ptr(next_type);
1778 case RESOLVE_STRUCT_OR_ARRAY:
1779 /* int, enum, void, ptr, func or func_proto is a sink
1780 * for struct and array
1781 */
1782 return !btf_type_is_modifier(next_type) &&
1783 !btf_type_is_array(next_type) &&
1784 !btf_type_is_struct(next_type);
1785 default:
1786 BUG();
1787 }
1788}
1789
1790static bool env_type_is_resolved(const struct btf_verifier_env *env,
1791 u32 type_id)
1792{
1793 /* base BTF types should be resolved by now */
1794 if (type_id < env->btf->start_id)
1795 return true;
1796
1797 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1798}
1799
1800static int env_stack_push(struct btf_verifier_env *env,
1801 const struct btf_type *t, u32 type_id)
1802{
1803 const struct btf *btf = env->btf;
1804 struct resolve_vertex *v;
1805
1806 if (env->top_stack == MAX_RESOLVE_DEPTH)
1807 return -E2BIG;
1808
1809 if (type_id < btf->start_id
1810 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1811 return -EEXIST;
1812
1813 env->visit_states[type_id - btf->start_id] = VISITED;
1814
1815 v = &env->stack[env->top_stack++];
1816 v->t = t;
1817 v->type_id = type_id;
1818 v->next_member = 0;
1819
1820 if (env->resolve_mode == RESOLVE_TBD) {
1821 if (btf_type_is_ptr(t))
1822 env->resolve_mode = RESOLVE_PTR;
1823 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1824 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1825 }
1826
1827 return 0;
1828}
1829
1830static void env_stack_set_next_member(struct btf_verifier_env *env,
1831 u16 next_member)
1832{
1833 env->stack[env->top_stack - 1].next_member = next_member;
1834}
1835
1836static void env_stack_pop_resolved(struct btf_verifier_env *env,
1837 u32 resolved_type_id,
1838 u32 resolved_size)
1839{
1840 u32 type_id = env->stack[--(env->top_stack)].type_id;
1841 struct btf *btf = env->btf;
1842
1843 type_id -= btf->start_id; /* adjust to local type id */
1844 btf->resolved_sizes[type_id] = resolved_size;
1845 btf->resolved_ids[type_id] = resolved_type_id;
1846 env->visit_states[type_id] = RESOLVED;
1847}
1848
1849static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1850{
1851 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1852}
1853
1854/* Resolve the size of a passed-in "type"
1855 *
1856 * type: is an array (e.g. u32 array[x][y])
1857 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1858 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1859 * corresponds to the return type.
1860 * *elem_type: u32
1861 * *elem_id: id of u32
1862 * *total_nelems: (x * y). Hence, individual elem size is
1863 * (*type_size / *total_nelems)
1864 * *type_id: id of type if it's changed within the function, 0 if not
1865 *
1866 * type: is not an array (e.g. const struct X)
1867 * return type: type "struct X"
1868 * *type_size: sizeof(struct X)
1869 * *elem_type: same as return type ("struct X")
1870 * *elem_id: 0
1871 * *total_nelems: 1
1872 * *type_id: id of type if it's changed within the function, 0 if not
1873 */
1874static const struct btf_type *
1875__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1876 u32 *type_size, const struct btf_type **elem_type,
1877 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1878{
1879 const struct btf_type *array_type = NULL;
1880 const struct btf_array *array = NULL;
1881 u32 i, size, nelems = 1, id = 0;
1882
1883 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1884 switch (BTF_INFO_KIND(type->info)) {
1885 /* type->size can be used */
1886 case BTF_KIND_INT:
1887 case BTF_KIND_STRUCT:
1888 case BTF_KIND_UNION:
1889 case BTF_KIND_ENUM:
1890 case BTF_KIND_FLOAT:
1891 case BTF_KIND_ENUM64:
1892 size = type->size;
1893 goto resolved;
1894
1895 case BTF_KIND_PTR:
1896 size = sizeof(void *);
1897 goto resolved;
1898
1899 /* Modifiers */
1900 case BTF_KIND_TYPEDEF:
1901 case BTF_KIND_VOLATILE:
1902 case BTF_KIND_CONST:
1903 case BTF_KIND_RESTRICT:
1904 case BTF_KIND_TYPE_TAG:
1905 id = type->type;
1906 type = btf_type_by_id(btf, type->type);
1907 break;
1908
1909 case BTF_KIND_ARRAY:
1910 if (!array_type)
1911 array_type = type;
1912 array = btf_type_array(type);
1913 if (nelems && array->nelems > U32_MAX / nelems)
1914 return ERR_PTR(-EINVAL);
1915 nelems *= array->nelems;
1916 type = btf_type_by_id(btf, array->type);
1917 break;
1918
1919 /* type without size */
1920 default:
1921 return ERR_PTR(-EINVAL);
1922 }
1923 }
1924
1925 return ERR_PTR(-EINVAL);
1926
1927resolved:
1928 if (nelems && size > U32_MAX / nelems)
1929 return ERR_PTR(-EINVAL);
1930
1931 *type_size = nelems * size;
1932 if (total_nelems)
1933 *total_nelems = nelems;
1934 if (elem_type)
1935 *elem_type = type;
1936 if (elem_id)
1937 *elem_id = array ? array->type : 0;
1938 if (type_id && id)
1939 *type_id = id;
1940
1941 return array_type ? : type;
1942}
1943
1944const struct btf_type *
1945btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1946 u32 *type_size)
1947{
1948 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1949}
1950
1951static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1952{
1953 while (type_id < btf->start_id)
1954 btf = btf->base_btf;
1955
1956 return btf->resolved_ids[type_id - btf->start_id];
1957}
1958
1959/* The input param "type_id" must point to a needs_resolve type */
1960static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1961 u32 *type_id)
1962{
1963 *type_id = btf_resolved_type_id(btf, *type_id);
1964 return btf_type_by_id(btf, *type_id);
1965}
1966
1967static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1968{
1969 while (type_id < btf->start_id)
1970 btf = btf->base_btf;
1971
1972 return btf->resolved_sizes[type_id - btf->start_id];
1973}
1974
1975const struct btf_type *btf_type_id_size(const struct btf *btf,
1976 u32 *type_id, u32 *ret_size)
1977{
1978 const struct btf_type *size_type;
1979 u32 size_type_id = *type_id;
1980 u32 size = 0;
1981
1982 size_type = btf_type_by_id(btf, size_type_id);
1983 if (btf_type_nosize_or_null(size_type))
1984 return NULL;
1985
1986 if (btf_type_has_size(size_type)) {
1987 size = size_type->size;
1988 } else if (btf_type_is_array(size_type)) {
1989 size = btf_resolved_type_size(btf, size_type_id);
1990 } else if (btf_type_is_ptr(size_type)) {
1991 size = sizeof(void *);
1992 } else {
1993 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1994 !btf_type_is_var(size_type)))
1995 return NULL;
1996
1997 size_type_id = btf_resolved_type_id(btf, size_type_id);
1998 size_type = btf_type_by_id(btf, size_type_id);
1999 if (btf_type_nosize_or_null(size_type))
2000 return NULL;
2001 else if (btf_type_has_size(size_type))
2002 size = size_type->size;
2003 else if (btf_type_is_array(size_type))
2004 size = btf_resolved_type_size(btf, size_type_id);
2005 else if (btf_type_is_ptr(size_type))
2006 size = sizeof(void *);
2007 else
2008 return NULL;
2009 }
2010
2011 *type_id = size_type_id;
2012 if (ret_size)
2013 *ret_size = size;
2014
2015 return size_type;
2016}
2017
2018static int btf_df_check_member(struct btf_verifier_env *env,
2019 const struct btf_type *struct_type,
2020 const struct btf_member *member,
2021 const struct btf_type *member_type)
2022{
2023 btf_verifier_log_basic(env, struct_type,
2024 "Unsupported check_member");
2025 return -EINVAL;
2026}
2027
2028static int btf_df_check_kflag_member(struct btf_verifier_env *env,
2029 const struct btf_type *struct_type,
2030 const struct btf_member *member,
2031 const struct btf_type *member_type)
2032{
2033 btf_verifier_log_basic(env, struct_type,
2034 "Unsupported check_kflag_member");
2035 return -EINVAL;
2036}
2037
2038/* Used for ptr, array struct/union and float type members.
2039 * int, enum and modifier types have their specific callback functions.
2040 */
2041static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
2042 const struct btf_type *struct_type,
2043 const struct btf_member *member,
2044 const struct btf_type *member_type)
2045{
2046 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2047 btf_verifier_log_member(env, struct_type, member,
2048 "Invalid member bitfield_size");
2049 return -EINVAL;
2050 }
2051
2052 /* bitfield size is 0, so member->offset represents bit offset only.
2053 * It is safe to call non kflag check_member variants.
2054 */
2055 return btf_type_ops(member_type)->check_member(env, struct_type,
2056 member,
2057 member_type);
2058}
2059
2060static int btf_df_resolve(struct btf_verifier_env *env,
2061 const struct resolve_vertex *v)
2062{
2063 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2064 return -EINVAL;
2065}
2066
2067static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2068 u32 type_id, void *data, u8 bits_offsets,
2069 struct btf_show *show)
2070{
2071 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2072}
2073
2074static int btf_int_check_member(struct btf_verifier_env *env,
2075 const struct btf_type *struct_type,
2076 const struct btf_member *member,
2077 const struct btf_type *member_type)
2078{
2079 u32 int_data = btf_type_int(member_type);
2080 u32 struct_bits_off = member->offset;
2081 u32 struct_size = struct_type->size;
2082 u32 nr_copy_bits;
2083 u32 bytes_offset;
2084
2085 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2086 btf_verifier_log_member(env, struct_type, member,
2087 "bits_offset exceeds U32_MAX");
2088 return -EINVAL;
2089 }
2090
2091 struct_bits_off += BTF_INT_OFFSET(int_data);
2092 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2093 nr_copy_bits = BTF_INT_BITS(int_data) +
2094 BITS_PER_BYTE_MASKED(struct_bits_off);
2095
2096 if (nr_copy_bits > BITS_PER_U128) {
2097 btf_verifier_log_member(env, struct_type, member,
2098 "nr_copy_bits exceeds 128");
2099 return -EINVAL;
2100 }
2101
2102 if (struct_size < bytes_offset ||
2103 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2104 btf_verifier_log_member(env, struct_type, member,
2105 "Member exceeds struct_size");
2106 return -EINVAL;
2107 }
2108
2109 return 0;
2110}
2111
2112static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2113 const struct btf_type *struct_type,
2114 const struct btf_member *member,
2115 const struct btf_type *member_type)
2116{
2117 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2118 u32 int_data = btf_type_int(member_type);
2119 u32 struct_size = struct_type->size;
2120 u32 nr_copy_bits;
2121
2122 /* a regular int type is required for the kflag int member */
2123 if (!btf_type_int_is_regular(member_type)) {
2124 btf_verifier_log_member(env, struct_type, member,
2125 "Invalid member base type");
2126 return -EINVAL;
2127 }
2128
2129 /* check sanity of bitfield size */
2130 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2131 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2132 nr_int_data_bits = BTF_INT_BITS(int_data);
2133 if (!nr_bits) {
2134 /* Not a bitfield member, member offset must be at byte
2135 * boundary.
2136 */
2137 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2138 btf_verifier_log_member(env, struct_type, member,
2139 "Invalid member offset");
2140 return -EINVAL;
2141 }
2142
2143 nr_bits = nr_int_data_bits;
2144 } else if (nr_bits > nr_int_data_bits) {
2145 btf_verifier_log_member(env, struct_type, member,
2146 "Invalid member bitfield_size");
2147 return -EINVAL;
2148 }
2149
2150 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2151 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2152 if (nr_copy_bits > BITS_PER_U128) {
2153 btf_verifier_log_member(env, struct_type, member,
2154 "nr_copy_bits exceeds 128");
2155 return -EINVAL;
2156 }
2157
2158 if (struct_size < bytes_offset ||
2159 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2160 btf_verifier_log_member(env, struct_type, member,
2161 "Member exceeds struct_size");
2162 return -EINVAL;
2163 }
2164
2165 return 0;
2166}
2167
2168static s32 btf_int_check_meta(struct btf_verifier_env *env,
2169 const struct btf_type *t,
2170 u32 meta_left)
2171{
2172 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2173 u16 encoding;
2174
2175 if (meta_left < meta_needed) {
2176 btf_verifier_log_basic(env, t,
2177 "meta_left:%u meta_needed:%u",
2178 meta_left, meta_needed);
2179 return -EINVAL;
2180 }
2181
2182 if (btf_type_vlen(t)) {
2183 btf_verifier_log_type(env, t, "vlen != 0");
2184 return -EINVAL;
2185 }
2186
2187 if (btf_type_kflag(t)) {
2188 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2189 return -EINVAL;
2190 }
2191
2192 int_data = btf_type_int(t);
2193 if (int_data & ~BTF_INT_MASK) {
2194 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2195 int_data);
2196 return -EINVAL;
2197 }
2198
2199 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2200
2201 if (nr_bits > BITS_PER_U128) {
2202 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2203 BITS_PER_U128);
2204 return -EINVAL;
2205 }
2206
2207 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2208 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2209 return -EINVAL;
2210 }
2211
2212 /*
2213 * Only one of the encoding bits is allowed and it
2214 * should be sufficient for the pretty print purpose (i.e. decoding).
2215 * Multiple bits can be allowed later if it is found
2216 * to be insufficient.
2217 */
2218 encoding = BTF_INT_ENCODING(int_data);
2219 if (encoding &&
2220 encoding != BTF_INT_SIGNED &&
2221 encoding != BTF_INT_CHAR &&
2222 encoding != BTF_INT_BOOL) {
2223 btf_verifier_log_type(env, t, "Unsupported encoding");
2224 return -ENOTSUPP;
2225 }
2226
2227 btf_verifier_log_type(env, t, NULL);
2228
2229 return meta_needed;
2230}
2231
2232static void btf_int_log(struct btf_verifier_env *env,
2233 const struct btf_type *t)
2234{
2235 int int_data = btf_type_int(t);
2236
2237 btf_verifier_log(env,
2238 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2239 t->size, BTF_INT_OFFSET(int_data),
2240 BTF_INT_BITS(int_data),
2241 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2242}
2243
2244static void btf_int128_print(struct btf_show *show, void *data)
2245{
2246 /* data points to a __int128 number.
2247 * Suppose
2248 * int128_num = *(__int128 *)data;
2249 * The below formulas shows what upper_num and lower_num represents:
2250 * upper_num = int128_num >> 64;
2251 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2252 */
2253 u64 upper_num, lower_num;
2254
2255#ifdef __BIG_ENDIAN_BITFIELD
2256 upper_num = *(u64 *)data;
2257 lower_num = *(u64 *)(data + 8);
2258#else
2259 upper_num = *(u64 *)(data + 8);
2260 lower_num = *(u64 *)data;
2261#endif
2262 if (upper_num == 0)
2263 btf_show_type_value(show, "0x%llx", lower_num);
2264 else
2265 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2266 lower_num);
2267}
2268
2269static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2270 u16 right_shift_bits)
2271{
2272 u64 upper_num, lower_num;
2273
2274#ifdef __BIG_ENDIAN_BITFIELD
2275 upper_num = print_num[0];
2276 lower_num = print_num[1];
2277#else
2278 upper_num = print_num[1];
2279 lower_num = print_num[0];
2280#endif
2281
2282 /* shake out un-needed bits by shift/or operations */
2283 if (left_shift_bits >= 64) {
2284 upper_num = lower_num << (left_shift_bits - 64);
2285 lower_num = 0;
2286 } else {
2287 upper_num = (upper_num << left_shift_bits) |
2288 (lower_num >> (64 - left_shift_bits));
2289 lower_num = lower_num << left_shift_bits;
2290 }
2291
2292 if (right_shift_bits >= 64) {
2293 lower_num = upper_num >> (right_shift_bits - 64);
2294 upper_num = 0;
2295 } else {
2296 lower_num = (lower_num >> right_shift_bits) |
2297 (upper_num << (64 - right_shift_bits));
2298 upper_num = upper_num >> right_shift_bits;
2299 }
2300
2301#ifdef __BIG_ENDIAN_BITFIELD
2302 print_num[0] = upper_num;
2303 print_num[1] = lower_num;
2304#else
2305 print_num[0] = lower_num;
2306 print_num[1] = upper_num;
2307#endif
2308}
2309
2310static void btf_bitfield_show(void *data, u8 bits_offset,
2311 u8 nr_bits, struct btf_show *show)
2312{
2313 u16 left_shift_bits, right_shift_bits;
2314 u8 nr_copy_bytes;
2315 u8 nr_copy_bits;
2316 u64 print_num[2] = {};
2317
2318 nr_copy_bits = nr_bits + bits_offset;
2319 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2320
2321 memcpy(print_num, data, nr_copy_bytes);
2322
2323#ifdef __BIG_ENDIAN_BITFIELD
2324 left_shift_bits = bits_offset;
2325#else
2326 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2327#endif
2328 right_shift_bits = BITS_PER_U128 - nr_bits;
2329
2330 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2331 btf_int128_print(show, print_num);
2332}
2333
2334
2335static void btf_int_bits_show(const struct btf *btf,
2336 const struct btf_type *t,
2337 void *data, u8 bits_offset,
2338 struct btf_show *show)
2339{
2340 u32 int_data = btf_type_int(t);
2341 u8 nr_bits = BTF_INT_BITS(int_data);
2342 u8 total_bits_offset;
2343
2344 /*
2345 * bits_offset is at most 7.
2346 * BTF_INT_OFFSET() cannot exceed 128 bits.
2347 */
2348 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2349 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2350 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2351 btf_bitfield_show(data, bits_offset, nr_bits, show);
2352}
2353
2354static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2355 u32 type_id, void *data, u8 bits_offset,
2356 struct btf_show *show)
2357{
2358 u32 int_data = btf_type_int(t);
2359 u8 encoding = BTF_INT_ENCODING(int_data);
2360 bool sign = encoding & BTF_INT_SIGNED;
2361 u8 nr_bits = BTF_INT_BITS(int_data);
2362 void *safe_data;
2363
2364 safe_data = btf_show_start_type(show, t, type_id, data);
2365 if (!safe_data)
2366 return;
2367
2368 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2369 BITS_PER_BYTE_MASKED(nr_bits)) {
2370 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2371 goto out;
2372 }
2373
2374 switch (nr_bits) {
2375 case 128:
2376 btf_int128_print(show, safe_data);
2377 break;
2378 case 64:
2379 if (sign)
2380 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2381 else
2382 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2383 break;
2384 case 32:
2385 if (sign)
2386 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2387 else
2388 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2389 break;
2390 case 16:
2391 if (sign)
2392 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2393 else
2394 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2395 break;
2396 case 8:
2397 if (show->state.array_encoding == BTF_INT_CHAR) {
2398 /* check for null terminator */
2399 if (show->state.array_terminated)
2400 break;
2401 if (*(char *)data == '\0') {
2402 show->state.array_terminated = 1;
2403 break;
2404 }
2405 if (isprint(*(char *)data)) {
2406 btf_show_type_value(show, "'%c'",
2407 *(char *)safe_data);
2408 break;
2409 }
2410 }
2411 if (sign)
2412 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2413 else
2414 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2415 break;
2416 default:
2417 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2418 break;
2419 }
2420out:
2421 btf_show_end_type(show);
2422}
2423
2424static const struct btf_kind_operations int_ops = {
2425 .check_meta = btf_int_check_meta,
2426 .resolve = btf_df_resolve,
2427 .check_member = btf_int_check_member,
2428 .check_kflag_member = btf_int_check_kflag_member,
2429 .log_details = btf_int_log,
2430 .show = btf_int_show,
2431};
2432
2433static int btf_modifier_check_member(struct btf_verifier_env *env,
2434 const struct btf_type *struct_type,
2435 const struct btf_member *member,
2436 const struct btf_type *member_type)
2437{
2438 const struct btf_type *resolved_type;
2439 u32 resolved_type_id = member->type;
2440 struct btf_member resolved_member;
2441 struct btf *btf = env->btf;
2442
2443 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2444 if (!resolved_type) {
2445 btf_verifier_log_member(env, struct_type, member,
2446 "Invalid member");
2447 return -EINVAL;
2448 }
2449
2450 resolved_member = *member;
2451 resolved_member.type = resolved_type_id;
2452
2453 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2454 &resolved_member,
2455 resolved_type);
2456}
2457
2458static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2459 const struct btf_type *struct_type,
2460 const struct btf_member *member,
2461 const struct btf_type *member_type)
2462{
2463 const struct btf_type *resolved_type;
2464 u32 resolved_type_id = member->type;
2465 struct btf_member resolved_member;
2466 struct btf *btf = env->btf;
2467
2468 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2469 if (!resolved_type) {
2470 btf_verifier_log_member(env, struct_type, member,
2471 "Invalid member");
2472 return -EINVAL;
2473 }
2474
2475 resolved_member = *member;
2476 resolved_member.type = resolved_type_id;
2477
2478 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2479 &resolved_member,
2480 resolved_type);
2481}
2482
2483static int btf_ptr_check_member(struct btf_verifier_env *env,
2484 const struct btf_type *struct_type,
2485 const struct btf_member *member,
2486 const struct btf_type *member_type)
2487{
2488 u32 struct_size, struct_bits_off, bytes_offset;
2489
2490 struct_size = struct_type->size;
2491 struct_bits_off = member->offset;
2492 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2493
2494 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2495 btf_verifier_log_member(env, struct_type, member,
2496 "Member is not byte aligned");
2497 return -EINVAL;
2498 }
2499
2500 if (struct_size - bytes_offset < sizeof(void *)) {
2501 btf_verifier_log_member(env, struct_type, member,
2502 "Member exceeds struct_size");
2503 return -EINVAL;
2504 }
2505
2506 return 0;
2507}
2508
2509static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2510 const struct btf_type *t,
2511 u32 meta_left)
2512{
2513 const char *value;
2514
2515 if (btf_type_vlen(t)) {
2516 btf_verifier_log_type(env, t, "vlen != 0");
2517 return -EINVAL;
2518 }
2519
2520 if (btf_type_kflag(t)) {
2521 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2522 return -EINVAL;
2523 }
2524
2525 if (!BTF_TYPE_ID_VALID(t->type)) {
2526 btf_verifier_log_type(env, t, "Invalid type_id");
2527 return -EINVAL;
2528 }
2529
2530 /* typedef/type_tag type must have a valid name, and other ref types,
2531 * volatile, const, restrict, should have a null name.
2532 */
2533 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2534 if (!t->name_off ||
2535 !btf_name_valid_identifier(env->btf, t->name_off)) {
2536 btf_verifier_log_type(env, t, "Invalid name");
2537 return -EINVAL;
2538 }
2539 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2540 value = btf_name_by_offset(env->btf, t->name_off);
2541 if (!value || !value[0]) {
2542 btf_verifier_log_type(env, t, "Invalid name");
2543 return -EINVAL;
2544 }
2545 } else {
2546 if (t->name_off) {
2547 btf_verifier_log_type(env, t, "Invalid name");
2548 return -EINVAL;
2549 }
2550 }
2551
2552 btf_verifier_log_type(env, t, NULL);
2553
2554 return 0;
2555}
2556
2557static int btf_modifier_resolve(struct btf_verifier_env *env,
2558 const struct resolve_vertex *v)
2559{
2560 const struct btf_type *t = v->t;
2561 const struct btf_type *next_type;
2562 u32 next_type_id = t->type;
2563 struct btf *btf = env->btf;
2564
2565 next_type = btf_type_by_id(btf, next_type_id);
2566 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2567 btf_verifier_log_type(env, v->t, "Invalid type_id");
2568 return -EINVAL;
2569 }
2570
2571 if (!env_type_is_resolve_sink(env, next_type) &&
2572 !env_type_is_resolved(env, next_type_id))
2573 return env_stack_push(env, next_type, next_type_id);
2574
2575 /* Figure out the resolved next_type_id with size.
2576 * They will be stored in the current modifier's
2577 * resolved_ids and resolved_sizes such that it can
2578 * save us a few type-following when we use it later (e.g. in
2579 * pretty print).
2580 */
2581 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2582 if (env_type_is_resolved(env, next_type_id))
2583 next_type = btf_type_id_resolve(btf, &next_type_id);
2584
2585 /* "typedef void new_void", "const void"...etc */
2586 if (!btf_type_is_void(next_type) &&
2587 !btf_type_is_fwd(next_type) &&
2588 !btf_type_is_func_proto(next_type)) {
2589 btf_verifier_log_type(env, v->t, "Invalid type_id");
2590 return -EINVAL;
2591 }
2592 }
2593
2594 env_stack_pop_resolved(env, next_type_id, 0);
2595
2596 return 0;
2597}
2598
2599static int btf_var_resolve(struct btf_verifier_env *env,
2600 const struct resolve_vertex *v)
2601{
2602 const struct btf_type *next_type;
2603 const struct btf_type *t = v->t;
2604 u32 next_type_id = t->type;
2605 struct btf *btf = env->btf;
2606
2607 next_type = btf_type_by_id(btf, next_type_id);
2608 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2609 btf_verifier_log_type(env, v->t, "Invalid type_id");
2610 return -EINVAL;
2611 }
2612
2613 if (!env_type_is_resolve_sink(env, next_type) &&
2614 !env_type_is_resolved(env, next_type_id))
2615 return env_stack_push(env, next_type, next_type_id);
2616
2617 if (btf_type_is_modifier(next_type)) {
2618 const struct btf_type *resolved_type;
2619 u32 resolved_type_id;
2620
2621 resolved_type_id = next_type_id;
2622 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2623
2624 if (btf_type_is_ptr(resolved_type) &&
2625 !env_type_is_resolve_sink(env, resolved_type) &&
2626 !env_type_is_resolved(env, resolved_type_id))
2627 return env_stack_push(env, resolved_type,
2628 resolved_type_id);
2629 }
2630
2631 /* We must resolve to something concrete at this point, no
2632 * forward types or similar that would resolve to size of
2633 * zero is allowed.
2634 */
2635 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2636 btf_verifier_log_type(env, v->t, "Invalid type_id");
2637 return -EINVAL;
2638 }
2639
2640 env_stack_pop_resolved(env, next_type_id, 0);
2641
2642 return 0;
2643}
2644
2645static int btf_ptr_resolve(struct btf_verifier_env *env,
2646 const struct resolve_vertex *v)
2647{
2648 const struct btf_type *next_type;
2649 const struct btf_type *t = v->t;
2650 u32 next_type_id = t->type;
2651 struct btf *btf = env->btf;
2652
2653 next_type = btf_type_by_id(btf, next_type_id);
2654 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2655 btf_verifier_log_type(env, v->t, "Invalid type_id");
2656 return -EINVAL;
2657 }
2658
2659 if (!env_type_is_resolve_sink(env, next_type) &&
2660 !env_type_is_resolved(env, next_type_id))
2661 return env_stack_push(env, next_type, next_type_id);
2662
2663 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2664 * the modifier may have stopped resolving when it was resolved
2665 * to a ptr (last-resolved-ptr).
2666 *
2667 * We now need to continue from the last-resolved-ptr to
2668 * ensure the last-resolved-ptr will not referring back to
2669 * the current ptr (t).
2670 */
2671 if (btf_type_is_modifier(next_type)) {
2672 const struct btf_type *resolved_type;
2673 u32 resolved_type_id;
2674
2675 resolved_type_id = next_type_id;
2676 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2677
2678 if (btf_type_is_ptr(resolved_type) &&
2679 !env_type_is_resolve_sink(env, resolved_type) &&
2680 !env_type_is_resolved(env, resolved_type_id))
2681 return env_stack_push(env, resolved_type,
2682 resolved_type_id);
2683 }
2684
2685 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2686 if (env_type_is_resolved(env, next_type_id))
2687 next_type = btf_type_id_resolve(btf, &next_type_id);
2688
2689 if (!btf_type_is_void(next_type) &&
2690 !btf_type_is_fwd(next_type) &&
2691 !btf_type_is_func_proto(next_type)) {
2692 btf_verifier_log_type(env, v->t, "Invalid type_id");
2693 return -EINVAL;
2694 }
2695 }
2696
2697 env_stack_pop_resolved(env, next_type_id, 0);
2698
2699 return 0;
2700}
2701
2702static void btf_modifier_show(const struct btf *btf,
2703 const struct btf_type *t,
2704 u32 type_id, void *data,
2705 u8 bits_offset, struct btf_show *show)
2706{
2707 if (btf->resolved_ids)
2708 t = btf_type_id_resolve(btf, &type_id);
2709 else
2710 t = btf_type_skip_modifiers(btf, type_id, NULL);
2711
2712 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2713}
2714
2715static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2716 u32 type_id, void *data, u8 bits_offset,
2717 struct btf_show *show)
2718{
2719 t = btf_type_id_resolve(btf, &type_id);
2720
2721 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2722}
2723
2724static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2725 u32 type_id, void *data, u8 bits_offset,
2726 struct btf_show *show)
2727{
2728 void *safe_data;
2729
2730 safe_data = btf_show_start_type(show, t, type_id, data);
2731 if (!safe_data)
2732 return;
2733
2734 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2735 if (show->flags & BTF_SHOW_PTR_RAW)
2736 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2737 else
2738 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2739 btf_show_end_type(show);
2740}
2741
2742static void btf_ref_type_log(struct btf_verifier_env *env,
2743 const struct btf_type *t)
2744{
2745 btf_verifier_log(env, "type_id=%u", t->type);
2746}
2747
2748static struct btf_kind_operations modifier_ops = {
2749 .check_meta = btf_ref_type_check_meta,
2750 .resolve = btf_modifier_resolve,
2751 .check_member = btf_modifier_check_member,
2752 .check_kflag_member = btf_modifier_check_kflag_member,
2753 .log_details = btf_ref_type_log,
2754 .show = btf_modifier_show,
2755};
2756
2757static struct btf_kind_operations ptr_ops = {
2758 .check_meta = btf_ref_type_check_meta,
2759 .resolve = btf_ptr_resolve,
2760 .check_member = btf_ptr_check_member,
2761 .check_kflag_member = btf_generic_check_kflag_member,
2762 .log_details = btf_ref_type_log,
2763 .show = btf_ptr_show,
2764};
2765
2766static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2767 const struct btf_type *t,
2768 u32 meta_left)
2769{
2770 if (btf_type_vlen(t)) {
2771 btf_verifier_log_type(env, t, "vlen != 0");
2772 return -EINVAL;
2773 }
2774
2775 if (t->type) {
2776 btf_verifier_log_type(env, t, "type != 0");
2777 return -EINVAL;
2778 }
2779
2780 /* fwd type must have a valid name */
2781 if (!t->name_off ||
2782 !btf_name_valid_identifier(env->btf, t->name_off)) {
2783 btf_verifier_log_type(env, t, "Invalid name");
2784 return -EINVAL;
2785 }
2786
2787 btf_verifier_log_type(env, t, NULL);
2788
2789 return 0;
2790}
2791
2792static void btf_fwd_type_log(struct btf_verifier_env *env,
2793 const struct btf_type *t)
2794{
2795 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2796}
2797
2798static struct btf_kind_operations fwd_ops = {
2799 .check_meta = btf_fwd_check_meta,
2800 .resolve = btf_df_resolve,
2801 .check_member = btf_df_check_member,
2802 .check_kflag_member = btf_df_check_kflag_member,
2803 .log_details = btf_fwd_type_log,
2804 .show = btf_df_show,
2805};
2806
2807static int btf_array_check_member(struct btf_verifier_env *env,
2808 const struct btf_type *struct_type,
2809 const struct btf_member *member,
2810 const struct btf_type *member_type)
2811{
2812 u32 struct_bits_off = member->offset;
2813 u32 struct_size, bytes_offset;
2814 u32 array_type_id, array_size;
2815 struct btf *btf = env->btf;
2816
2817 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2818 btf_verifier_log_member(env, struct_type, member,
2819 "Member is not byte aligned");
2820 return -EINVAL;
2821 }
2822
2823 array_type_id = member->type;
2824 btf_type_id_size(btf, &array_type_id, &array_size);
2825 struct_size = struct_type->size;
2826 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2827 if (struct_size - bytes_offset < array_size) {
2828 btf_verifier_log_member(env, struct_type, member,
2829 "Member exceeds struct_size");
2830 return -EINVAL;
2831 }
2832
2833 return 0;
2834}
2835
2836static s32 btf_array_check_meta(struct btf_verifier_env *env,
2837 const struct btf_type *t,
2838 u32 meta_left)
2839{
2840 const struct btf_array *array = btf_type_array(t);
2841 u32 meta_needed = sizeof(*array);
2842
2843 if (meta_left < meta_needed) {
2844 btf_verifier_log_basic(env, t,
2845 "meta_left:%u meta_needed:%u",
2846 meta_left, meta_needed);
2847 return -EINVAL;
2848 }
2849
2850 /* array type should not have a name */
2851 if (t->name_off) {
2852 btf_verifier_log_type(env, t, "Invalid name");
2853 return -EINVAL;
2854 }
2855
2856 if (btf_type_vlen(t)) {
2857 btf_verifier_log_type(env, t, "vlen != 0");
2858 return -EINVAL;
2859 }
2860
2861 if (btf_type_kflag(t)) {
2862 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2863 return -EINVAL;
2864 }
2865
2866 if (t->size) {
2867 btf_verifier_log_type(env, t, "size != 0");
2868 return -EINVAL;
2869 }
2870
2871 /* Array elem type and index type cannot be in type void,
2872 * so !array->type and !array->index_type are not allowed.
2873 */
2874 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2875 btf_verifier_log_type(env, t, "Invalid elem");
2876 return -EINVAL;
2877 }
2878
2879 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2880 btf_verifier_log_type(env, t, "Invalid index");
2881 return -EINVAL;
2882 }
2883
2884 btf_verifier_log_type(env, t, NULL);
2885
2886 return meta_needed;
2887}
2888
2889static int btf_array_resolve(struct btf_verifier_env *env,
2890 const struct resolve_vertex *v)
2891{
2892 const struct btf_array *array = btf_type_array(v->t);
2893 const struct btf_type *elem_type, *index_type;
2894 u32 elem_type_id, index_type_id;
2895 struct btf *btf = env->btf;
2896 u32 elem_size;
2897
2898 /* Check array->index_type */
2899 index_type_id = array->index_type;
2900 index_type = btf_type_by_id(btf, index_type_id);
2901 if (btf_type_nosize_or_null(index_type) ||
2902 btf_type_is_resolve_source_only(index_type)) {
2903 btf_verifier_log_type(env, v->t, "Invalid index");
2904 return -EINVAL;
2905 }
2906
2907 if (!env_type_is_resolve_sink(env, index_type) &&
2908 !env_type_is_resolved(env, index_type_id))
2909 return env_stack_push(env, index_type, index_type_id);
2910
2911 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2912 if (!index_type || !btf_type_is_int(index_type) ||
2913 !btf_type_int_is_regular(index_type)) {
2914 btf_verifier_log_type(env, v->t, "Invalid index");
2915 return -EINVAL;
2916 }
2917
2918 /* Check array->type */
2919 elem_type_id = array->type;
2920 elem_type = btf_type_by_id(btf, elem_type_id);
2921 if (btf_type_nosize_or_null(elem_type) ||
2922 btf_type_is_resolve_source_only(elem_type)) {
2923 btf_verifier_log_type(env, v->t,
2924 "Invalid elem");
2925 return -EINVAL;
2926 }
2927
2928 if (!env_type_is_resolve_sink(env, elem_type) &&
2929 !env_type_is_resolved(env, elem_type_id))
2930 return env_stack_push(env, elem_type, elem_type_id);
2931
2932 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2933 if (!elem_type) {
2934 btf_verifier_log_type(env, v->t, "Invalid elem");
2935 return -EINVAL;
2936 }
2937
2938 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2939 btf_verifier_log_type(env, v->t, "Invalid array of int");
2940 return -EINVAL;
2941 }
2942
2943 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2944 btf_verifier_log_type(env, v->t,
2945 "Array size overflows U32_MAX");
2946 return -EINVAL;
2947 }
2948
2949 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2950
2951 return 0;
2952}
2953
2954static void btf_array_log(struct btf_verifier_env *env,
2955 const struct btf_type *t)
2956{
2957 const struct btf_array *array = btf_type_array(t);
2958
2959 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2960 array->type, array->index_type, array->nelems);
2961}
2962
2963static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2964 u32 type_id, void *data, u8 bits_offset,
2965 struct btf_show *show)
2966{
2967 const struct btf_array *array = btf_type_array(t);
2968 const struct btf_kind_operations *elem_ops;
2969 const struct btf_type *elem_type;
2970 u32 i, elem_size = 0, elem_type_id;
2971 u16 encoding = 0;
2972
2973 elem_type_id = array->type;
2974 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2975 if (elem_type && btf_type_has_size(elem_type))
2976 elem_size = elem_type->size;
2977
2978 if (elem_type && btf_type_is_int(elem_type)) {
2979 u32 int_type = btf_type_int(elem_type);
2980
2981 encoding = BTF_INT_ENCODING(int_type);
2982
2983 /*
2984 * BTF_INT_CHAR encoding never seems to be set for
2985 * char arrays, so if size is 1 and element is
2986 * printable as a char, we'll do that.
2987 */
2988 if (elem_size == 1)
2989 encoding = BTF_INT_CHAR;
2990 }
2991
2992 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2993 return;
2994
2995 if (!elem_type)
2996 goto out;
2997 elem_ops = btf_type_ops(elem_type);
2998
2999 for (i = 0; i < array->nelems; i++) {
3000
3001 btf_show_start_array_member(show);
3002
3003 elem_ops->show(btf, elem_type, elem_type_id, data,
3004 bits_offset, show);
3005 data += elem_size;
3006
3007 btf_show_end_array_member(show);
3008
3009 if (show->state.array_terminated)
3010 break;
3011 }
3012out:
3013 btf_show_end_array_type(show);
3014}
3015
3016static void btf_array_show(const struct btf *btf, const struct btf_type *t,
3017 u32 type_id, void *data, u8 bits_offset,
3018 struct btf_show *show)
3019{
3020 const struct btf_member *m = show->state.member;
3021
3022 /*
3023 * First check if any members would be shown (are non-zero).
3024 * See comments above "struct btf_show" definition for more
3025 * details on how this works at a high-level.
3026 */
3027 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3028 if (!show->state.depth_check) {
3029 show->state.depth_check = show->state.depth + 1;
3030 show->state.depth_to_show = 0;
3031 }
3032 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3033 show->state.member = m;
3034
3035 if (show->state.depth_check != show->state.depth + 1)
3036 return;
3037 show->state.depth_check = 0;
3038
3039 if (show->state.depth_to_show <= show->state.depth)
3040 return;
3041 /*
3042 * Reaching here indicates we have recursed and found
3043 * non-zero array member(s).
3044 */
3045 }
3046 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3047}
3048
3049static struct btf_kind_operations array_ops = {
3050 .check_meta = btf_array_check_meta,
3051 .resolve = btf_array_resolve,
3052 .check_member = btf_array_check_member,
3053 .check_kflag_member = btf_generic_check_kflag_member,
3054 .log_details = btf_array_log,
3055 .show = btf_array_show,
3056};
3057
3058static int btf_struct_check_member(struct btf_verifier_env *env,
3059 const struct btf_type *struct_type,
3060 const struct btf_member *member,
3061 const struct btf_type *member_type)
3062{
3063 u32 struct_bits_off = member->offset;
3064 u32 struct_size, bytes_offset;
3065
3066 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3067 btf_verifier_log_member(env, struct_type, member,
3068 "Member is not byte aligned");
3069 return -EINVAL;
3070 }
3071
3072 struct_size = struct_type->size;
3073 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3074 if (struct_size - bytes_offset < member_type->size) {
3075 btf_verifier_log_member(env, struct_type, member,
3076 "Member exceeds struct_size");
3077 return -EINVAL;
3078 }
3079
3080 return 0;
3081}
3082
3083static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3084 const struct btf_type *t,
3085 u32 meta_left)
3086{
3087 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3088 const struct btf_member *member;
3089 u32 meta_needed, last_offset;
3090 struct btf *btf = env->btf;
3091 u32 struct_size = t->size;
3092 u32 offset;
3093 u16 i;
3094
3095 meta_needed = btf_type_vlen(t) * sizeof(*member);
3096 if (meta_left < meta_needed) {
3097 btf_verifier_log_basic(env, t,
3098 "meta_left:%u meta_needed:%u",
3099 meta_left, meta_needed);
3100 return -EINVAL;
3101 }
3102
3103 /* struct type either no name or a valid one */
3104 if (t->name_off &&
3105 !btf_name_valid_identifier(env->btf, t->name_off)) {
3106 btf_verifier_log_type(env, t, "Invalid name");
3107 return -EINVAL;
3108 }
3109
3110 btf_verifier_log_type(env, t, NULL);
3111
3112 last_offset = 0;
3113 for_each_member(i, t, member) {
3114 if (!btf_name_offset_valid(btf, member->name_off)) {
3115 btf_verifier_log_member(env, t, member,
3116 "Invalid member name_offset:%u",
3117 member->name_off);
3118 return -EINVAL;
3119 }
3120
3121 /* struct member either no name or a valid one */
3122 if (member->name_off &&
3123 !btf_name_valid_identifier(btf, member->name_off)) {
3124 btf_verifier_log_member(env, t, member, "Invalid name");
3125 return -EINVAL;
3126 }
3127 /* A member cannot be in type void */
3128 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3129 btf_verifier_log_member(env, t, member,
3130 "Invalid type_id");
3131 return -EINVAL;
3132 }
3133
3134 offset = __btf_member_bit_offset(t, member);
3135 if (is_union && offset) {
3136 btf_verifier_log_member(env, t, member,
3137 "Invalid member bits_offset");
3138 return -EINVAL;
3139 }
3140
3141 /*
3142 * ">" instead of ">=" because the last member could be
3143 * "char a[0];"
3144 */
3145 if (last_offset > offset) {
3146 btf_verifier_log_member(env, t, member,
3147 "Invalid member bits_offset");
3148 return -EINVAL;
3149 }
3150
3151 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3152 btf_verifier_log_member(env, t, member,
3153 "Member bits_offset exceeds its struct size");
3154 return -EINVAL;
3155 }
3156
3157 btf_verifier_log_member(env, t, member, NULL);
3158 last_offset = offset;
3159 }
3160
3161 return meta_needed;
3162}
3163
3164static int btf_struct_resolve(struct btf_verifier_env *env,
3165 const struct resolve_vertex *v)
3166{
3167 const struct btf_member *member;
3168 int err;
3169 u16 i;
3170
3171 /* Before continue resolving the next_member,
3172 * ensure the last member is indeed resolved to a
3173 * type with size info.
3174 */
3175 if (v->next_member) {
3176 const struct btf_type *last_member_type;
3177 const struct btf_member *last_member;
3178 u32 last_member_type_id;
3179
3180 last_member = btf_type_member(v->t) + v->next_member - 1;
3181 last_member_type_id = last_member->type;
3182 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3183 last_member_type_id)))
3184 return -EINVAL;
3185
3186 last_member_type = btf_type_by_id(env->btf,
3187 last_member_type_id);
3188 if (btf_type_kflag(v->t))
3189 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3190 last_member,
3191 last_member_type);
3192 else
3193 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3194 last_member,
3195 last_member_type);
3196 if (err)
3197 return err;
3198 }
3199
3200 for_each_member_from(i, v->next_member, v->t, member) {
3201 u32 member_type_id = member->type;
3202 const struct btf_type *member_type = btf_type_by_id(env->btf,
3203 member_type_id);
3204
3205 if (btf_type_nosize_or_null(member_type) ||
3206 btf_type_is_resolve_source_only(member_type)) {
3207 btf_verifier_log_member(env, v->t, member,
3208 "Invalid member");
3209 return -EINVAL;
3210 }
3211
3212 if (!env_type_is_resolve_sink(env, member_type) &&
3213 !env_type_is_resolved(env, member_type_id)) {
3214 env_stack_set_next_member(env, i + 1);
3215 return env_stack_push(env, member_type, member_type_id);
3216 }
3217
3218 if (btf_type_kflag(v->t))
3219 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3220 member,
3221 member_type);
3222 else
3223 err = btf_type_ops(member_type)->check_member(env, v->t,
3224 member,
3225 member_type);
3226 if (err)
3227 return err;
3228 }
3229
3230 env_stack_pop_resolved(env, 0, 0);
3231
3232 return 0;
3233}
3234
3235static void btf_struct_log(struct btf_verifier_env *env,
3236 const struct btf_type *t)
3237{
3238 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3239}
3240
3241enum {
3242 BTF_FIELD_IGNORE = 0,
3243 BTF_FIELD_FOUND = 1,
3244};
3245
3246struct btf_field_info {
3247 enum btf_field_type type;
3248 u32 off;
3249 union {
3250 struct {
3251 u32 type_id;
3252 } kptr;
3253 struct {
3254 const char *node_name;
3255 u32 value_btf_id;
3256 } graph_root;
3257 };
3258};
3259
3260static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3261 u32 off, int sz, enum btf_field_type field_type,
3262 struct btf_field_info *info)
3263{
3264 if (!__btf_type_is_struct(t))
3265 return BTF_FIELD_IGNORE;
3266 if (t->size != sz)
3267 return BTF_FIELD_IGNORE;
3268 info->type = field_type;
3269 info->off = off;
3270 return BTF_FIELD_FOUND;
3271}
3272
3273static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3274 u32 off, int sz, struct btf_field_info *info)
3275{
3276 enum btf_field_type type;
3277 u32 res_id;
3278
3279 /* Permit modifiers on the pointer itself */
3280 if (btf_type_is_volatile(t))
3281 t = btf_type_by_id(btf, t->type);
3282 /* For PTR, sz is always == 8 */
3283 if (!btf_type_is_ptr(t))
3284 return BTF_FIELD_IGNORE;
3285 t = btf_type_by_id(btf, t->type);
3286
3287 if (!btf_type_is_type_tag(t))
3288 return BTF_FIELD_IGNORE;
3289 /* Reject extra tags */
3290 if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3291 return -EINVAL;
3292 if (!strcmp("kptr_untrusted", __btf_name_by_offset(btf, t->name_off)))
3293 type = BPF_KPTR_UNREF;
3294 else if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3295 type = BPF_KPTR_REF;
3296 else if (!strcmp("percpu_kptr", __btf_name_by_offset(btf, t->name_off)))
3297 type = BPF_KPTR_PERCPU;
3298 else
3299 return -EINVAL;
3300
3301 /* Get the base type */
3302 t = btf_type_skip_modifiers(btf, t->type, &res_id);
3303 /* Only pointer to struct is allowed */
3304 if (!__btf_type_is_struct(t))
3305 return -EINVAL;
3306
3307 info->type = type;
3308 info->off = off;
3309 info->kptr.type_id = res_id;
3310 return BTF_FIELD_FOUND;
3311}
3312
3313const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
3314 int comp_idx, const char *tag_key)
3315{
3316 const char *value = NULL;
3317 int i;
3318
3319 for (i = 1; i < btf_nr_types(btf); i++) {
3320 const struct btf_type *t = btf_type_by_id(btf, i);
3321 int len = strlen(tag_key);
3322
3323 if (!btf_type_is_decl_tag(t))
3324 continue;
3325 if (pt != btf_type_by_id(btf, t->type) ||
3326 btf_type_decl_tag(t)->component_idx != comp_idx)
3327 continue;
3328 if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
3329 continue;
3330 /* Prevent duplicate entries for same type */
3331 if (value)
3332 return ERR_PTR(-EEXIST);
3333 value = __btf_name_by_offset(btf, t->name_off) + len;
3334 }
3335 if (!value)
3336 return ERR_PTR(-ENOENT);
3337 return value;
3338}
3339
3340static int
3341btf_find_graph_root(const struct btf *btf, const struct btf_type *pt,
3342 const struct btf_type *t, int comp_idx, u32 off,
3343 int sz, struct btf_field_info *info,
3344 enum btf_field_type head_type)
3345{
3346 const char *node_field_name;
3347 const char *value_type;
3348 s32 id;
3349
3350 if (!__btf_type_is_struct(t))
3351 return BTF_FIELD_IGNORE;
3352 if (t->size != sz)
3353 return BTF_FIELD_IGNORE;
3354 value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
3355 if (IS_ERR(value_type))
3356 return -EINVAL;
3357 node_field_name = strstr(value_type, ":");
3358 if (!node_field_name)
3359 return -EINVAL;
3360 value_type = kstrndup(value_type, node_field_name - value_type, GFP_KERNEL | __GFP_NOWARN);
3361 if (!value_type)
3362 return -ENOMEM;
3363 id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
3364 kfree(value_type);
3365 if (id < 0)
3366 return id;
3367 node_field_name++;
3368 if (str_is_empty(node_field_name))
3369 return -EINVAL;
3370 info->type = head_type;
3371 info->off = off;
3372 info->graph_root.value_btf_id = id;
3373 info->graph_root.node_name = node_field_name;
3374 return BTF_FIELD_FOUND;
3375}
3376
3377#define field_mask_test_name(field_type, field_type_str) \
3378 if (field_mask & field_type && !strcmp(name, field_type_str)) { \
3379 type = field_type; \
3380 goto end; \
3381 }
3382
3383static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask,
3384 int *align, int *sz)
3385{
3386 int type = 0;
3387
3388 if (field_mask & BPF_SPIN_LOCK) {
3389 if (!strcmp(name, "bpf_spin_lock")) {
3390 if (*seen_mask & BPF_SPIN_LOCK)
3391 return -E2BIG;
3392 *seen_mask |= BPF_SPIN_LOCK;
3393 type = BPF_SPIN_LOCK;
3394 goto end;
3395 }
3396 }
3397 if (field_mask & BPF_TIMER) {
3398 if (!strcmp(name, "bpf_timer")) {
3399 if (*seen_mask & BPF_TIMER)
3400 return -E2BIG;
3401 *seen_mask |= BPF_TIMER;
3402 type = BPF_TIMER;
3403 goto end;
3404 }
3405 }
3406 field_mask_test_name(BPF_LIST_HEAD, "bpf_list_head");
3407 field_mask_test_name(BPF_LIST_NODE, "bpf_list_node");
3408 field_mask_test_name(BPF_RB_ROOT, "bpf_rb_root");
3409 field_mask_test_name(BPF_RB_NODE, "bpf_rb_node");
3410 field_mask_test_name(BPF_REFCOUNT, "bpf_refcount");
3411
3412 /* Only return BPF_KPTR when all other types with matchable names fail */
3413 if (field_mask & BPF_KPTR) {
3414 type = BPF_KPTR_REF;
3415 goto end;
3416 }
3417 return 0;
3418end:
3419 *sz = btf_field_type_size(type);
3420 *align = btf_field_type_align(type);
3421 return type;
3422}
3423
3424#undef field_mask_test_name
3425
3426static int btf_find_struct_field(const struct btf *btf,
3427 const struct btf_type *t, u32 field_mask,
3428 struct btf_field_info *info, int info_cnt)
3429{
3430 int ret, idx = 0, align, sz, field_type;
3431 const struct btf_member *member;
3432 struct btf_field_info tmp;
3433 u32 i, off, seen_mask = 0;
3434
3435 for_each_member(i, t, member) {
3436 const struct btf_type *member_type = btf_type_by_id(btf,
3437 member->type);
3438
3439 field_type = btf_get_field_type(__btf_name_by_offset(btf, member_type->name_off),
3440 field_mask, &seen_mask, &align, &sz);
3441 if (field_type == 0)
3442 continue;
3443 if (field_type < 0)
3444 return field_type;
3445
3446 off = __btf_member_bit_offset(t, member);
3447 if (off % 8)
3448 /* valid C code cannot generate such BTF */
3449 return -EINVAL;
3450 off /= 8;
3451 if (off % align)
3452 continue;
3453
3454 switch (field_type) {
3455 case BPF_SPIN_LOCK:
3456 case BPF_TIMER:
3457 case BPF_LIST_NODE:
3458 case BPF_RB_NODE:
3459 case BPF_REFCOUNT:
3460 ret = btf_find_struct(btf, member_type, off, sz, field_type,
3461 idx < info_cnt ? &info[idx] : &tmp);
3462 if (ret < 0)
3463 return ret;
3464 break;
3465 case BPF_KPTR_UNREF:
3466 case BPF_KPTR_REF:
3467 case BPF_KPTR_PERCPU:
3468 ret = btf_find_kptr(btf, member_type, off, sz,
3469 idx < info_cnt ? &info[idx] : &tmp);
3470 if (ret < 0)
3471 return ret;
3472 break;
3473 case BPF_LIST_HEAD:
3474 case BPF_RB_ROOT:
3475 ret = btf_find_graph_root(btf, t, member_type,
3476 i, off, sz,
3477 idx < info_cnt ? &info[idx] : &tmp,
3478 field_type);
3479 if (ret < 0)
3480 return ret;
3481 break;
3482 default:
3483 return -EFAULT;
3484 }
3485
3486 if (ret == BTF_FIELD_IGNORE)
3487 continue;
3488 if (idx >= info_cnt)
3489 return -E2BIG;
3490 ++idx;
3491 }
3492 return idx;
3493}
3494
3495static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3496 u32 field_mask, struct btf_field_info *info,
3497 int info_cnt)
3498{
3499 int ret, idx = 0, align, sz, field_type;
3500 const struct btf_var_secinfo *vsi;
3501 struct btf_field_info tmp;
3502 u32 i, off, seen_mask = 0;
3503
3504 for_each_vsi(i, t, vsi) {
3505 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3506 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3507
3508 field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off),
3509 field_mask, &seen_mask, &align, &sz);
3510 if (field_type == 0)
3511 continue;
3512 if (field_type < 0)
3513 return field_type;
3514
3515 off = vsi->offset;
3516 if (vsi->size != sz)
3517 continue;
3518 if (off % align)
3519 continue;
3520
3521 switch (field_type) {
3522 case BPF_SPIN_LOCK:
3523 case BPF_TIMER:
3524 case BPF_LIST_NODE:
3525 case BPF_RB_NODE:
3526 case BPF_REFCOUNT:
3527 ret = btf_find_struct(btf, var_type, off, sz, field_type,
3528 idx < info_cnt ? &info[idx] : &tmp);
3529 if (ret < 0)
3530 return ret;
3531 break;
3532 case BPF_KPTR_UNREF:
3533 case BPF_KPTR_REF:
3534 case BPF_KPTR_PERCPU:
3535 ret = btf_find_kptr(btf, var_type, off, sz,
3536 idx < info_cnt ? &info[idx] : &tmp);
3537 if (ret < 0)
3538 return ret;
3539 break;
3540 case BPF_LIST_HEAD:
3541 case BPF_RB_ROOT:
3542 ret = btf_find_graph_root(btf, var, var_type,
3543 -1, off, sz,
3544 idx < info_cnt ? &info[idx] : &tmp,
3545 field_type);
3546 if (ret < 0)
3547 return ret;
3548 break;
3549 default:
3550 return -EFAULT;
3551 }
3552
3553 if (ret == BTF_FIELD_IGNORE)
3554 continue;
3555 if (idx >= info_cnt)
3556 return -E2BIG;
3557 ++idx;
3558 }
3559 return idx;
3560}
3561
3562static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3563 u32 field_mask, struct btf_field_info *info,
3564 int info_cnt)
3565{
3566 if (__btf_type_is_struct(t))
3567 return btf_find_struct_field(btf, t, field_mask, info, info_cnt);
3568 else if (btf_type_is_datasec(t))
3569 return btf_find_datasec_var(btf, t, field_mask, info, info_cnt);
3570 return -EINVAL;
3571}
3572
3573static int btf_parse_kptr(const struct btf *btf, struct btf_field *field,
3574 struct btf_field_info *info)
3575{
3576 struct module *mod = NULL;
3577 const struct btf_type *t;
3578 /* If a matching btf type is found in kernel or module BTFs, kptr_ref
3579 * is that BTF, otherwise it's program BTF
3580 */
3581 struct btf *kptr_btf;
3582 int ret;
3583 s32 id;
3584
3585 /* Find type in map BTF, and use it to look up the matching type
3586 * in vmlinux or module BTFs, by name and kind.
3587 */
3588 t = btf_type_by_id(btf, info->kptr.type_id);
3589 id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3590 &kptr_btf);
3591 if (id == -ENOENT) {
3592 /* btf_parse_kptr should only be called w/ btf = program BTF */
3593 WARN_ON_ONCE(btf_is_kernel(btf));
3594
3595 /* Type exists only in program BTF. Assume that it's a MEM_ALLOC
3596 * kptr allocated via bpf_obj_new
3597 */
3598 field->kptr.dtor = NULL;
3599 id = info->kptr.type_id;
3600 kptr_btf = (struct btf *)btf;
3601 btf_get(kptr_btf);
3602 goto found_dtor;
3603 }
3604 if (id < 0)
3605 return id;
3606
3607 /* Find and stash the function pointer for the destruction function that
3608 * needs to be eventually invoked from the map free path.
3609 */
3610 if (info->type == BPF_KPTR_REF) {
3611 const struct btf_type *dtor_func;
3612 const char *dtor_func_name;
3613 unsigned long addr;
3614 s32 dtor_btf_id;
3615
3616 /* This call also serves as a whitelist of allowed objects that
3617 * can be used as a referenced pointer and be stored in a map at
3618 * the same time.
3619 */
3620 dtor_btf_id = btf_find_dtor_kfunc(kptr_btf, id);
3621 if (dtor_btf_id < 0) {
3622 ret = dtor_btf_id;
3623 goto end_btf;
3624 }
3625
3626 dtor_func = btf_type_by_id(kptr_btf, dtor_btf_id);
3627 if (!dtor_func) {
3628 ret = -ENOENT;
3629 goto end_btf;
3630 }
3631
3632 if (btf_is_module(kptr_btf)) {
3633 mod = btf_try_get_module(kptr_btf);
3634 if (!mod) {
3635 ret = -ENXIO;
3636 goto end_btf;
3637 }
3638 }
3639
3640 /* We already verified dtor_func to be btf_type_is_func
3641 * in register_btf_id_dtor_kfuncs.
3642 */
3643 dtor_func_name = __btf_name_by_offset(kptr_btf, dtor_func->name_off);
3644 addr = kallsyms_lookup_name(dtor_func_name);
3645 if (!addr) {
3646 ret = -EINVAL;
3647 goto end_mod;
3648 }
3649 field->kptr.dtor = (void *)addr;
3650 }
3651
3652found_dtor:
3653 field->kptr.btf_id = id;
3654 field->kptr.btf = kptr_btf;
3655 field->kptr.module = mod;
3656 return 0;
3657end_mod:
3658 module_put(mod);
3659end_btf:
3660 btf_put(kptr_btf);
3661 return ret;
3662}
3663
3664static int btf_parse_graph_root(const struct btf *btf,
3665 struct btf_field *field,
3666 struct btf_field_info *info,
3667 const char *node_type_name,
3668 size_t node_type_align)
3669{
3670 const struct btf_type *t, *n = NULL;
3671 const struct btf_member *member;
3672 u32 offset;
3673 int i;
3674
3675 t = btf_type_by_id(btf, info->graph_root.value_btf_id);
3676 /* We've already checked that value_btf_id is a struct type. We
3677 * just need to figure out the offset of the list_node, and
3678 * verify its type.
3679 */
3680 for_each_member(i, t, member) {
3681 if (strcmp(info->graph_root.node_name,
3682 __btf_name_by_offset(btf, member->name_off)))
3683 continue;
3684 /* Invalid BTF, two members with same name */
3685 if (n)
3686 return -EINVAL;
3687 n = btf_type_by_id(btf, member->type);
3688 if (!__btf_type_is_struct(n))
3689 return -EINVAL;
3690 if (strcmp(node_type_name, __btf_name_by_offset(btf, n->name_off)))
3691 return -EINVAL;
3692 offset = __btf_member_bit_offset(n, member);
3693 if (offset % 8)
3694 return -EINVAL;
3695 offset /= 8;
3696 if (offset % node_type_align)
3697 return -EINVAL;
3698
3699 field->graph_root.btf = (struct btf *)btf;
3700 field->graph_root.value_btf_id = info->graph_root.value_btf_id;
3701 field->graph_root.node_offset = offset;
3702 }
3703 if (!n)
3704 return -ENOENT;
3705 return 0;
3706}
3707
3708static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
3709 struct btf_field_info *info)
3710{
3711 return btf_parse_graph_root(btf, field, info, "bpf_list_node",
3712 __alignof__(struct bpf_list_node));
3713}
3714
3715static int btf_parse_rb_root(const struct btf *btf, struct btf_field *field,
3716 struct btf_field_info *info)
3717{
3718 return btf_parse_graph_root(btf, field, info, "bpf_rb_node",
3719 __alignof__(struct bpf_rb_node));
3720}
3721
3722static int btf_field_cmp(const void *_a, const void *_b, const void *priv)
3723{
3724 const struct btf_field *a = (const struct btf_field *)_a;
3725 const struct btf_field *b = (const struct btf_field *)_b;
3726
3727 if (a->offset < b->offset)
3728 return -1;
3729 else if (a->offset > b->offset)
3730 return 1;
3731 return 0;
3732}
3733
3734struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
3735 u32 field_mask, u32 value_size)
3736{
3737 struct btf_field_info info_arr[BTF_FIELDS_MAX];
3738 u32 next_off = 0, field_type_size;
3739 struct btf_record *rec;
3740 int ret, i, cnt;
3741
3742 ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
3743 if (ret < 0)
3744 return ERR_PTR(ret);
3745 if (!ret)
3746 return NULL;
3747
3748 cnt = ret;
3749 /* This needs to be kzalloc to zero out padding and unused fields, see
3750 * comment in btf_record_equal.
3751 */
3752 rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);
3753 if (!rec)
3754 return ERR_PTR(-ENOMEM);
3755
3756 rec->spin_lock_off = -EINVAL;
3757 rec->timer_off = -EINVAL;
3758 rec->refcount_off = -EINVAL;
3759 for (i = 0; i < cnt; i++) {
3760 field_type_size = btf_field_type_size(info_arr[i].type);
3761 if (info_arr[i].off + field_type_size > value_size) {
3762 WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
3763 ret = -EFAULT;
3764 goto end;
3765 }
3766 if (info_arr[i].off < next_off) {
3767 ret = -EEXIST;
3768 goto end;
3769 }
3770 next_off = info_arr[i].off + field_type_size;
3771
3772 rec->field_mask |= info_arr[i].type;
3773 rec->fields[i].offset = info_arr[i].off;
3774 rec->fields[i].type = info_arr[i].type;
3775 rec->fields[i].size = field_type_size;
3776
3777 switch (info_arr[i].type) {
3778 case BPF_SPIN_LOCK:
3779 WARN_ON_ONCE(rec->spin_lock_off >= 0);
3780 /* Cache offset for faster lookup at runtime */
3781 rec->spin_lock_off = rec->fields[i].offset;
3782 break;
3783 case BPF_TIMER:
3784 WARN_ON_ONCE(rec->timer_off >= 0);
3785 /* Cache offset for faster lookup at runtime */
3786 rec->timer_off = rec->fields[i].offset;
3787 break;
3788 case BPF_REFCOUNT:
3789 WARN_ON_ONCE(rec->refcount_off >= 0);
3790 /* Cache offset for faster lookup at runtime */
3791 rec->refcount_off = rec->fields[i].offset;
3792 break;
3793 case BPF_KPTR_UNREF:
3794 case BPF_KPTR_REF:
3795 case BPF_KPTR_PERCPU:
3796 ret = btf_parse_kptr(btf, &rec->fields[i], &info_arr[i]);
3797 if (ret < 0)
3798 goto end;
3799 break;
3800 case BPF_LIST_HEAD:
3801 ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
3802 if (ret < 0)
3803 goto end;
3804 break;
3805 case BPF_RB_ROOT:
3806 ret = btf_parse_rb_root(btf, &rec->fields[i], &info_arr[i]);
3807 if (ret < 0)
3808 goto end;
3809 break;
3810 case BPF_LIST_NODE:
3811 case BPF_RB_NODE:
3812 break;
3813 default:
3814 ret = -EFAULT;
3815 goto end;
3816 }
3817 rec->cnt++;
3818 }
3819
3820 /* bpf_{list_head, rb_node} require bpf_spin_lock */
3821 if ((btf_record_has_field(rec, BPF_LIST_HEAD) ||
3822 btf_record_has_field(rec, BPF_RB_ROOT)) && rec->spin_lock_off < 0) {
3823 ret = -EINVAL;
3824 goto end;
3825 }
3826
3827 if (rec->refcount_off < 0 &&
3828 btf_record_has_field(rec, BPF_LIST_NODE) &&
3829 btf_record_has_field(rec, BPF_RB_NODE)) {
3830 ret = -EINVAL;
3831 goto end;
3832 }
3833
3834 sort_r(rec->fields, rec->cnt, sizeof(struct btf_field), btf_field_cmp,
3835 NULL, rec);
3836
3837 return rec;
3838end:
3839 btf_record_free(rec);
3840 return ERR_PTR(ret);
3841}
3842
3843int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
3844{
3845 int i;
3846
3847 /* There are three types that signify ownership of some other type:
3848 * kptr_ref, bpf_list_head, bpf_rb_root.
3849 * kptr_ref only supports storing kernel types, which can't store
3850 * references to program allocated local types.
3851 *
3852 * Hence we only need to ensure that bpf_{list_head,rb_root} ownership
3853 * does not form cycles.
3854 */
3855 if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & BPF_GRAPH_ROOT))
3856 return 0;
3857 for (i = 0; i < rec->cnt; i++) {
3858 struct btf_struct_meta *meta;
3859 u32 btf_id;
3860
3861 if (!(rec->fields[i].type & BPF_GRAPH_ROOT))
3862 continue;
3863 btf_id = rec->fields[i].graph_root.value_btf_id;
3864 meta = btf_find_struct_meta(btf, btf_id);
3865 if (!meta)
3866 return -EFAULT;
3867 rec->fields[i].graph_root.value_rec = meta->record;
3868
3869 /* We need to set value_rec for all root types, but no need
3870 * to check ownership cycle for a type unless it's also a
3871 * node type.
3872 */
3873 if (!(rec->field_mask & BPF_GRAPH_NODE))
3874 continue;
3875
3876 /* We need to ensure ownership acyclicity among all types. The
3877 * proper way to do it would be to topologically sort all BTF
3878 * IDs based on the ownership edges, since there can be multiple
3879 * bpf_{list_head,rb_node} in a type. Instead, we use the
3880 * following resaoning:
3881 *
3882 * - A type can only be owned by another type in user BTF if it
3883 * has a bpf_{list,rb}_node. Let's call these node types.
3884 * - A type can only _own_ another type in user BTF if it has a
3885 * bpf_{list_head,rb_root}. Let's call these root types.
3886 *
3887 * We ensure that if a type is both a root and node, its
3888 * element types cannot be root types.
3889 *
3890 * To ensure acyclicity:
3891 *
3892 * When A is an root type but not a node, its ownership
3893 * chain can be:
3894 * A -> B -> C
3895 * Where:
3896 * - A is an root, e.g. has bpf_rb_root.
3897 * - B is both a root and node, e.g. has bpf_rb_node and
3898 * bpf_list_head.
3899 * - C is only an root, e.g. has bpf_list_node
3900 *
3901 * When A is both a root and node, some other type already
3902 * owns it in the BTF domain, hence it can not own
3903 * another root type through any of the ownership edges.
3904 * A -> B
3905 * Where:
3906 * - A is both an root and node.
3907 * - B is only an node.
3908 */
3909 if (meta->record->field_mask & BPF_GRAPH_ROOT)
3910 return -ELOOP;
3911 }
3912 return 0;
3913}
3914
3915static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3916 u32 type_id, void *data, u8 bits_offset,
3917 struct btf_show *show)
3918{
3919 const struct btf_member *member;
3920 void *safe_data;
3921 u32 i;
3922
3923 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3924 if (!safe_data)
3925 return;
3926
3927 for_each_member(i, t, member) {
3928 const struct btf_type *member_type = btf_type_by_id(btf,
3929 member->type);
3930 const struct btf_kind_operations *ops;
3931 u32 member_offset, bitfield_size;
3932 u32 bytes_offset;
3933 u8 bits8_offset;
3934
3935 btf_show_start_member(show, member);
3936
3937 member_offset = __btf_member_bit_offset(t, member);
3938 bitfield_size = __btf_member_bitfield_size(t, member);
3939 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3940 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3941 if (bitfield_size) {
3942 safe_data = btf_show_start_type(show, member_type,
3943 member->type,
3944 data + bytes_offset);
3945 if (safe_data)
3946 btf_bitfield_show(safe_data,
3947 bits8_offset,
3948 bitfield_size, show);
3949 btf_show_end_type(show);
3950 } else {
3951 ops = btf_type_ops(member_type);
3952 ops->show(btf, member_type, member->type,
3953 data + bytes_offset, bits8_offset, show);
3954 }
3955
3956 btf_show_end_member(show);
3957 }
3958
3959 btf_show_end_struct_type(show);
3960}
3961
3962static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3963 u32 type_id, void *data, u8 bits_offset,
3964 struct btf_show *show)
3965{
3966 const struct btf_member *m = show->state.member;
3967
3968 /*
3969 * First check if any members would be shown (are non-zero).
3970 * See comments above "struct btf_show" definition for more
3971 * details on how this works at a high-level.
3972 */
3973 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3974 if (!show->state.depth_check) {
3975 show->state.depth_check = show->state.depth + 1;
3976 show->state.depth_to_show = 0;
3977 }
3978 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3979 /* Restore saved member data here */
3980 show->state.member = m;
3981 if (show->state.depth_check != show->state.depth + 1)
3982 return;
3983 show->state.depth_check = 0;
3984
3985 if (show->state.depth_to_show <= show->state.depth)
3986 return;
3987 /*
3988 * Reaching here indicates we have recursed and found
3989 * non-zero child values.
3990 */
3991 }
3992
3993 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3994}
3995
3996static struct btf_kind_operations struct_ops = {
3997 .check_meta = btf_struct_check_meta,
3998 .resolve = btf_struct_resolve,
3999 .check_member = btf_struct_check_member,
4000 .check_kflag_member = btf_generic_check_kflag_member,
4001 .log_details = btf_struct_log,
4002 .show = btf_struct_show,
4003};
4004
4005static int btf_enum_check_member(struct btf_verifier_env *env,
4006 const struct btf_type *struct_type,
4007 const struct btf_member *member,
4008 const struct btf_type *member_type)
4009{
4010 u32 struct_bits_off = member->offset;
4011 u32 struct_size, bytes_offset;
4012
4013 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4014 btf_verifier_log_member(env, struct_type, member,
4015 "Member is not byte aligned");
4016 return -EINVAL;
4017 }
4018
4019 struct_size = struct_type->size;
4020 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
4021 if (struct_size - bytes_offset < member_type->size) {
4022 btf_verifier_log_member(env, struct_type, member,
4023 "Member exceeds struct_size");
4024 return -EINVAL;
4025 }
4026
4027 return 0;
4028}
4029
4030static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
4031 const struct btf_type *struct_type,
4032 const struct btf_member *member,
4033 const struct btf_type *member_type)
4034{
4035 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
4036 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
4037
4038 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
4039 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
4040 if (!nr_bits) {
4041 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4042 btf_verifier_log_member(env, struct_type, member,
4043 "Member is not byte aligned");
4044 return -EINVAL;
4045 }
4046
4047 nr_bits = int_bitsize;
4048 } else if (nr_bits > int_bitsize) {
4049 btf_verifier_log_member(env, struct_type, member,
4050 "Invalid member bitfield_size");
4051 return -EINVAL;
4052 }
4053
4054 struct_size = struct_type->size;
4055 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
4056 if (struct_size < bytes_end) {
4057 btf_verifier_log_member(env, struct_type, member,
4058 "Member exceeds struct_size");
4059 return -EINVAL;
4060 }
4061
4062 return 0;
4063}
4064
4065static s32 btf_enum_check_meta(struct btf_verifier_env *env,
4066 const struct btf_type *t,
4067 u32 meta_left)
4068{
4069 const struct btf_enum *enums = btf_type_enum(t);
4070 struct btf *btf = env->btf;
4071 const char *fmt_str;
4072 u16 i, nr_enums;
4073 u32 meta_needed;
4074
4075 nr_enums = btf_type_vlen(t);
4076 meta_needed = nr_enums * sizeof(*enums);
4077
4078 if (meta_left < meta_needed) {
4079 btf_verifier_log_basic(env, t,
4080 "meta_left:%u meta_needed:%u",
4081 meta_left, meta_needed);
4082 return -EINVAL;
4083 }
4084
4085 if (t->size > 8 || !is_power_of_2(t->size)) {
4086 btf_verifier_log_type(env, t, "Unexpected size");
4087 return -EINVAL;
4088 }
4089
4090 /* enum type either no name or a valid one */
4091 if (t->name_off &&
4092 !btf_name_valid_identifier(env->btf, t->name_off)) {
4093 btf_verifier_log_type(env, t, "Invalid name");
4094 return -EINVAL;
4095 }
4096
4097 btf_verifier_log_type(env, t, NULL);
4098
4099 for (i = 0; i < nr_enums; i++) {
4100 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4101 btf_verifier_log(env, "\tInvalid name_offset:%u",
4102 enums[i].name_off);
4103 return -EINVAL;
4104 }
4105
4106 /* enum member must have a valid name */
4107 if (!enums[i].name_off ||
4108 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4109 btf_verifier_log_type(env, t, "Invalid name");
4110 return -EINVAL;
4111 }
4112
4113 if (env->log.level == BPF_LOG_KERNEL)
4114 continue;
4115 fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
4116 btf_verifier_log(env, fmt_str,
4117 __btf_name_by_offset(btf, enums[i].name_off),
4118 enums[i].val);
4119 }
4120
4121 return meta_needed;
4122}
4123
4124static void btf_enum_log(struct btf_verifier_env *env,
4125 const struct btf_type *t)
4126{
4127 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4128}
4129
4130static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
4131 u32 type_id, void *data, u8 bits_offset,
4132 struct btf_show *show)
4133{
4134 const struct btf_enum *enums = btf_type_enum(t);
4135 u32 i, nr_enums = btf_type_vlen(t);
4136 void *safe_data;
4137 int v;
4138
4139 safe_data = btf_show_start_type(show, t, type_id, data);
4140 if (!safe_data)
4141 return;
4142
4143 v = *(int *)safe_data;
4144
4145 for (i = 0; i < nr_enums; i++) {
4146 if (v != enums[i].val)
4147 continue;
4148
4149 btf_show_type_value(show, "%s",
4150 __btf_name_by_offset(btf,
4151 enums[i].name_off));
4152
4153 btf_show_end_type(show);
4154 return;
4155 }
4156
4157 if (btf_type_kflag(t))
4158 btf_show_type_value(show, "%d", v);
4159 else
4160 btf_show_type_value(show, "%u", v);
4161 btf_show_end_type(show);
4162}
4163
4164static struct btf_kind_operations enum_ops = {
4165 .check_meta = btf_enum_check_meta,
4166 .resolve = btf_df_resolve,
4167 .check_member = btf_enum_check_member,
4168 .check_kflag_member = btf_enum_check_kflag_member,
4169 .log_details = btf_enum_log,
4170 .show = btf_enum_show,
4171};
4172
4173static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
4174 const struct btf_type *t,
4175 u32 meta_left)
4176{
4177 const struct btf_enum64 *enums = btf_type_enum64(t);
4178 struct btf *btf = env->btf;
4179 const char *fmt_str;
4180 u16 i, nr_enums;
4181 u32 meta_needed;
4182
4183 nr_enums = btf_type_vlen(t);
4184 meta_needed = nr_enums * sizeof(*enums);
4185
4186 if (meta_left < meta_needed) {
4187 btf_verifier_log_basic(env, t,
4188 "meta_left:%u meta_needed:%u",
4189 meta_left, meta_needed);
4190 return -EINVAL;
4191 }
4192
4193 if (t->size > 8 || !is_power_of_2(t->size)) {
4194 btf_verifier_log_type(env, t, "Unexpected size");
4195 return -EINVAL;
4196 }
4197
4198 /* enum type either no name or a valid one */
4199 if (t->name_off &&
4200 !btf_name_valid_identifier(env->btf, t->name_off)) {
4201 btf_verifier_log_type(env, t, "Invalid name");
4202 return -EINVAL;
4203 }
4204
4205 btf_verifier_log_type(env, t, NULL);
4206
4207 for (i = 0; i < nr_enums; i++) {
4208 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4209 btf_verifier_log(env, "\tInvalid name_offset:%u",
4210 enums[i].name_off);
4211 return -EINVAL;
4212 }
4213
4214 /* enum member must have a valid name */
4215 if (!enums[i].name_off ||
4216 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4217 btf_verifier_log_type(env, t, "Invalid name");
4218 return -EINVAL;
4219 }
4220
4221 if (env->log.level == BPF_LOG_KERNEL)
4222 continue;
4223
4224 fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
4225 btf_verifier_log(env, fmt_str,
4226 __btf_name_by_offset(btf, enums[i].name_off),
4227 btf_enum64_value(enums + i));
4228 }
4229
4230 return meta_needed;
4231}
4232
4233static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
4234 u32 type_id, void *data, u8 bits_offset,
4235 struct btf_show *show)
4236{
4237 const struct btf_enum64 *enums = btf_type_enum64(t);
4238 u32 i, nr_enums = btf_type_vlen(t);
4239 void *safe_data;
4240 s64 v;
4241
4242 safe_data = btf_show_start_type(show, t, type_id, data);
4243 if (!safe_data)
4244 return;
4245
4246 v = *(u64 *)safe_data;
4247
4248 for (i = 0; i < nr_enums; i++) {
4249 if (v != btf_enum64_value(enums + i))
4250 continue;
4251
4252 btf_show_type_value(show, "%s",
4253 __btf_name_by_offset(btf,
4254 enums[i].name_off));
4255
4256 btf_show_end_type(show);
4257 return;
4258 }
4259
4260 if (btf_type_kflag(t))
4261 btf_show_type_value(show, "%lld", v);
4262 else
4263 btf_show_type_value(show, "%llu", v);
4264 btf_show_end_type(show);
4265}
4266
4267static struct btf_kind_operations enum64_ops = {
4268 .check_meta = btf_enum64_check_meta,
4269 .resolve = btf_df_resolve,
4270 .check_member = btf_enum_check_member,
4271 .check_kflag_member = btf_enum_check_kflag_member,
4272 .log_details = btf_enum_log,
4273 .show = btf_enum64_show,
4274};
4275
4276static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
4277 const struct btf_type *t,
4278 u32 meta_left)
4279{
4280 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
4281
4282 if (meta_left < meta_needed) {
4283 btf_verifier_log_basic(env, t,
4284 "meta_left:%u meta_needed:%u",
4285 meta_left, meta_needed);
4286 return -EINVAL;
4287 }
4288
4289 if (t->name_off) {
4290 btf_verifier_log_type(env, t, "Invalid name");
4291 return -EINVAL;
4292 }
4293
4294 if (btf_type_kflag(t)) {
4295 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4296 return -EINVAL;
4297 }
4298
4299 btf_verifier_log_type(env, t, NULL);
4300
4301 return meta_needed;
4302}
4303
4304static void btf_func_proto_log(struct btf_verifier_env *env,
4305 const struct btf_type *t)
4306{
4307 const struct btf_param *args = (const struct btf_param *)(t + 1);
4308 u16 nr_args = btf_type_vlen(t), i;
4309
4310 btf_verifier_log(env, "return=%u args=(", t->type);
4311 if (!nr_args) {
4312 btf_verifier_log(env, "void");
4313 goto done;
4314 }
4315
4316 if (nr_args == 1 && !args[0].type) {
4317 /* Only one vararg */
4318 btf_verifier_log(env, "vararg");
4319 goto done;
4320 }
4321
4322 btf_verifier_log(env, "%u %s", args[0].type,
4323 __btf_name_by_offset(env->btf,
4324 args[0].name_off));
4325 for (i = 1; i < nr_args - 1; i++)
4326 btf_verifier_log(env, ", %u %s", args[i].type,
4327 __btf_name_by_offset(env->btf,
4328 args[i].name_off));
4329
4330 if (nr_args > 1) {
4331 const struct btf_param *last_arg = &args[nr_args - 1];
4332
4333 if (last_arg->type)
4334 btf_verifier_log(env, ", %u %s", last_arg->type,
4335 __btf_name_by_offset(env->btf,
4336 last_arg->name_off));
4337 else
4338 btf_verifier_log(env, ", vararg");
4339 }
4340
4341done:
4342 btf_verifier_log(env, ")");
4343}
4344
4345static struct btf_kind_operations func_proto_ops = {
4346 .check_meta = btf_func_proto_check_meta,
4347 .resolve = btf_df_resolve,
4348 /*
4349 * BTF_KIND_FUNC_PROTO cannot be directly referred by
4350 * a struct's member.
4351 *
4352 * It should be a function pointer instead.
4353 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
4354 *
4355 * Hence, there is no btf_func_check_member().
4356 */
4357 .check_member = btf_df_check_member,
4358 .check_kflag_member = btf_df_check_kflag_member,
4359 .log_details = btf_func_proto_log,
4360 .show = btf_df_show,
4361};
4362
4363static s32 btf_func_check_meta(struct btf_verifier_env *env,
4364 const struct btf_type *t,
4365 u32 meta_left)
4366{
4367 if (!t->name_off ||
4368 !btf_name_valid_identifier(env->btf, t->name_off)) {
4369 btf_verifier_log_type(env, t, "Invalid name");
4370 return -EINVAL;
4371 }
4372
4373 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
4374 btf_verifier_log_type(env, t, "Invalid func linkage");
4375 return -EINVAL;
4376 }
4377
4378 if (btf_type_kflag(t)) {
4379 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4380 return -EINVAL;
4381 }
4382
4383 btf_verifier_log_type(env, t, NULL);
4384
4385 return 0;
4386}
4387
4388static int btf_func_resolve(struct btf_verifier_env *env,
4389 const struct resolve_vertex *v)
4390{
4391 const struct btf_type *t = v->t;
4392 u32 next_type_id = t->type;
4393 int err;
4394
4395 err = btf_func_check(env, t);
4396 if (err)
4397 return err;
4398
4399 env_stack_pop_resolved(env, next_type_id, 0);
4400 return 0;
4401}
4402
4403static struct btf_kind_operations func_ops = {
4404 .check_meta = btf_func_check_meta,
4405 .resolve = btf_func_resolve,
4406 .check_member = btf_df_check_member,
4407 .check_kflag_member = btf_df_check_kflag_member,
4408 .log_details = btf_ref_type_log,
4409 .show = btf_df_show,
4410};
4411
4412static s32 btf_var_check_meta(struct btf_verifier_env *env,
4413 const struct btf_type *t,
4414 u32 meta_left)
4415{
4416 const struct btf_var *var;
4417 u32 meta_needed = sizeof(*var);
4418
4419 if (meta_left < meta_needed) {
4420 btf_verifier_log_basic(env, t,
4421 "meta_left:%u meta_needed:%u",
4422 meta_left, meta_needed);
4423 return -EINVAL;
4424 }
4425
4426 if (btf_type_vlen(t)) {
4427 btf_verifier_log_type(env, t, "vlen != 0");
4428 return -EINVAL;
4429 }
4430
4431 if (btf_type_kflag(t)) {
4432 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4433 return -EINVAL;
4434 }
4435
4436 if (!t->name_off ||
4437 !__btf_name_valid(env->btf, t->name_off)) {
4438 btf_verifier_log_type(env, t, "Invalid name");
4439 return -EINVAL;
4440 }
4441
4442 /* A var cannot be in type void */
4443 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4444 btf_verifier_log_type(env, t, "Invalid type_id");
4445 return -EINVAL;
4446 }
4447
4448 var = btf_type_var(t);
4449 if (var->linkage != BTF_VAR_STATIC &&
4450 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4451 btf_verifier_log_type(env, t, "Linkage not supported");
4452 return -EINVAL;
4453 }
4454
4455 btf_verifier_log_type(env, t, NULL);
4456
4457 return meta_needed;
4458}
4459
4460static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4461{
4462 const struct btf_var *var = btf_type_var(t);
4463
4464 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4465}
4466
4467static const struct btf_kind_operations var_ops = {
4468 .check_meta = btf_var_check_meta,
4469 .resolve = btf_var_resolve,
4470 .check_member = btf_df_check_member,
4471 .check_kflag_member = btf_df_check_kflag_member,
4472 .log_details = btf_var_log,
4473 .show = btf_var_show,
4474};
4475
4476static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4477 const struct btf_type *t,
4478 u32 meta_left)
4479{
4480 const struct btf_var_secinfo *vsi;
4481 u64 last_vsi_end_off = 0, sum = 0;
4482 u32 i, meta_needed;
4483
4484 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4485 if (meta_left < meta_needed) {
4486 btf_verifier_log_basic(env, t,
4487 "meta_left:%u meta_needed:%u",
4488 meta_left, meta_needed);
4489 return -EINVAL;
4490 }
4491
4492 if (!t->size) {
4493 btf_verifier_log_type(env, t, "size == 0");
4494 return -EINVAL;
4495 }
4496
4497 if (btf_type_kflag(t)) {
4498 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4499 return -EINVAL;
4500 }
4501
4502 if (!t->name_off ||
4503 !btf_name_valid_section(env->btf, t->name_off)) {
4504 btf_verifier_log_type(env, t, "Invalid name");
4505 return -EINVAL;
4506 }
4507
4508 btf_verifier_log_type(env, t, NULL);
4509
4510 for_each_vsi(i, t, vsi) {
4511 /* A var cannot be in type void */
4512 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4513 btf_verifier_log_vsi(env, t, vsi,
4514 "Invalid type_id");
4515 return -EINVAL;
4516 }
4517
4518 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4519 btf_verifier_log_vsi(env, t, vsi,
4520 "Invalid offset");
4521 return -EINVAL;
4522 }
4523
4524 if (!vsi->size || vsi->size > t->size) {
4525 btf_verifier_log_vsi(env, t, vsi,
4526 "Invalid size");
4527 return -EINVAL;
4528 }
4529
4530 last_vsi_end_off = vsi->offset + vsi->size;
4531 if (last_vsi_end_off > t->size) {
4532 btf_verifier_log_vsi(env, t, vsi,
4533 "Invalid offset+size");
4534 return -EINVAL;
4535 }
4536
4537 btf_verifier_log_vsi(env, t, vsi, NULL);
4538 sum += vsi->size;
4539 }
4540
4541 if (t->size < sum) {
4542 btf_verifier_log_type(env, t, "Invalid btf_info size");
4543 return -EINVAL;
4544 }
4545
4546 return meta_needed;
4547}
4548
4549static int btf_datasec_resolve(struct btf_verifier_env *env,
4550 const struct resolve_vertex *v)
4551{
4552 const struct btf_var_secinfo *vsi;
4553 struct btf *btf = env->btf;
4554 u16 i;
4555
4556 env->resolve_mode = RESOLVE_TBD;
4557 for_each_vsi_from(i, v->next_member, v->t, vsi) {
4558 u32 var_type_id = vsi->type, type_id, type_size = 0;
4559 const struct btf_type *var_type = btf_type_by_id(env->btf,
4560 var_type_id);
4561 if (!var_type || !btf_type_is_var(var_type)) {
4562 btf_verifier_log_vsi(env, v->t, vsi,
4563 "Not a VAR kind member");
4564 return -EINVAL;
4565 }
4566
4567 if (!env_type_is_resolve_sink(env, var_type) &&
4568 !env_type_is_resolved(env, var_type_id)) {
4569 env_stack_set_next_member(env, i + 1);
4570 return env_stack_push(env, var_type, var_type_id);
4571 }
4572
4573 type_id = var_type->type;
4574 if (!btf_type_id_size(btf, &type_id, &type_size)) {
4575 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4576 return -EINVAL;
4577 }
4578
4579 if (vsi->size < type_size) {
4580 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4581 return -EINVAL;
4582 }
4583 }
4584
4585 env_stack_pop_resolved(env, 0, 0);
4586 return 0;
4587}
4588
4589static void btf_datasec_log(struct btf_verifier_env *env,
4590 const struct btf_type *t)
4591{
4592 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4593}
4594
4595static void btf_datasec_show(const struct btf *btf,
4596 const struct btf_type *t, u32 type_id,
4597 void *data, u8 bits_offset,
4598 struct btf_show *show)
4599{
4600 const struct btf_var_secinfo *vsi;
4601 const struct btf_type *var;
4602 u32 i;
4603
4604 if (!btf_show_start_type(show, t, type_id, data))
4605 return;
4606
4607 btf_show_type_value(show, "section (\"%s\") = {",
4608 __btf_name_by_offset(btf, t->name_off));
4609 for_each_vsi(i, t, vsi) {
4610 var = btf_type_by_id(btf, vsi->type);
4611 if (i)
4612 btf_show(show, ",");
4613 btf_type_ops(var)->show(btf, var, vsi->type,
4614 data + vsi->offset, bits_offset, show);
4615 }
4616 btf_show_end_type(show);
4617}
4618
4619static const struct btf_kind_operations datasec_ops = {
4620 .check_meta = btf_datasec_check_meta,
4621 .resolve = btf_datasec_resolve,
4622 .check_member = btf_df_check_member,
4623 .check_kflag_member = btf_df_check_kflag_member,
4624 .log_details = btf_datasec_log,
4625 .show = btf_datasec_show,
4626};
4627
4628static s32 btf_float_check_meta(struct btf_verifier_env *env,
4629 const struct btf_type *t,
4630 u32 meta_left)
4631{
4632 if (btf_type_vlen(t)) {
4633 btf_verifier_log_type(env, t, "vlen != 0");
4634 return -EINVAL;
4635 }
4636
4637 if (btf_type_kflag(t)) {
4638 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4639 return -EINVAL;
4640 }
4641
4642 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4643 t->size != 16) {
4644 btf_verifier_log_type(env, t, "Invalid type_size");
4645 return -EINVAL;
4646 }
4647
4648 btf_verifier_log_type(env, t, NULL);
4649
4650 return 0;
4651}
4652
4653static int btf_float_check_member(struct btf_verifier_env *env,
4654 const struct btf_type *struct_type,
4655 const struct btf_member *member,
4656 const struct btf_type *member_type)
4657{
4658 u64 start_offset_bytes;
4659 u64 end_offset_bytes;
4660 u64 misalign_bits;
4661 u64 align_bytes;
4662 u64 align_bits;
4663
4664 /* Different architectures have different alignment requirements, so
4665 * here we check only for the reasonable minimum. This way we ensure
4666 * that types after CO-RE can pass the kernel BTF verifier.
4667 */
4668 align_bytes = min_t(u64, sizeof(void *), member_type->size);
4669 align_bits = align_bytes * BITS_PER_BYTE;
4670 div64_u64_rem(member->offset, align_bits, &misalign_bits);
4671 if (misalign_bits) {
4672 btf_verifier_log_member(env, struct_type, member,
4673 "Member is not properly aligned");
4674 return -EINVAL;
4675 }
4676
4677 start_offset_bytes = member->offset / BITS_PER_BYTE;
4678 end_offset_bytes = start_offset_bytes + member_type->size;
4679 if (end_offset_bytes > struct_type->size) {
4680 btf_verifier_log_member(env, struct_type, member,
4681 "Member exceeds struct_size");
4682 return -EINVAL;
4683 }
4684
4685 return 0;
4686}
4687
4688static void btf_float_log(struct btf_verifier_env *env,
4689 const struct btf_type *t)
4690{
4691 btf_verifier_log(env, "size=%u", t->size);
4692}
4693
4694static const struct btf_kind_operations float_ops = {
4695 .check_meta = btf_float_check_meta,
4696 .resolve = btf_df_resolve,
4697 .check_member = btf_float_check_member,
4698 .check_kflag_member = btf_generic_check_kflag_member,
4699 .log_details = btf_float_log,
4700 .show = btf_df_show,
4701};
4702
4703static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4704 const struct btf_type *t,
4705 u32 meta_left)
4706{
4707 const struct btf_decl_tag *tag;
4708 u32 meta_needed = sizeof(*tag);
4709 s32 component_idx;
4710 const char *value;
4711
4712 if (meta_left < meta_needed) {
4713 btf_verifier_log_basic(env, t,
4714 "meta_left:%u meta_needed:%u",
4715 meta_left, meta_needed);
4716 return -EINVAL;
4717 }
4718
4719 value = btf_name_by_offset(env->btf, t->name_off);
4720 if (!value || !value[0]) {
4721 btf_verifier_log_type(env, t, "Invalid value");
4722 return -EINVAL;
4723 }
4724
4725 if (btf_type_vlen(t)) {
4726 btf_verifier_log_type(env, t, "vlen != 0");
4727 return -EINVAL;
4728 }
4729
4730 if (btf_type_kflag(t)) {
4731 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4732 return -EINVAL;
4733 }
4734
4735 component_idx = btf_type_decl_tag(t)->component_idx;
4736 if (component_idx < -1) {
4737 btf_verifier_log_type(env, t, "Invalid component_idx");
4738 return -EINVAL;
4739 }
4740
4741 btf_verifier_log_type(env, t, NULL);
4742
4743 return meta_needed;
4744}
4745
4746static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4747 const struct resolve_vertex *v)
4748{
4749 const struct btf_type *next_type;
4750 const struct btf_type *t = v->t;
4751 u32 next_type_id = t->type;
4752 struct btf *btf = env->btf;
4753 s32 component_idx;
4754 u32 vlen;
4755
4756 next_type = btf_type_by_id(btf, next_type_id);
4757 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4758 btf_verifier_log_type(env, v->t, "Invalid type_id");
4759 return -EINVAL;
4760 }
4761
4762 if (!env_type_is_resolve_sink(env, next_type) &&
4763 !env_type_is_resolved(env, next_type_id))
4764 return env_stack_push(env, next_type, next_type_id);
4765
4766 component_idx = btf_type_decl_tag(t)->component_idx;
4767 if (component_idx != -1) {
4768 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4769 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4770 return -EINVAL;
4771 }
4772
4773 if (btf_type_is_struct(next_type)) {
4774 vlen = btf_type_vlen(next_type);
4775 } else {
4776 /* next_type should be a function */
4777 next_type = btf_type_by_id(btf, next_type->type);
4778 vlen = btf_type_vlen(next_type);
4779 }
4780
4781 if ((u32)component_idx >= vlen) {
4782 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4783 return -EINVAL;
4784 }
4785 }
4786
4787 env_stack_pop_resolved(env, next_type_id, 0);
4788
4789 return 0;
4790}
4791
4792static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
4793{
4794 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
4795 btf_type_decl_tag(t)->component_idx);
4796}
4797
4798static const struct btf_kind_operations decl_tag_ops = {
4799 .check_meta = btf_decl_tag_check_meta,
4800 .resolve = btf_decl_tag_resolve,
4801 .check_member = btf_df_check_member,
4802 .check_kflag_member = btf_df_check_kflag_member,
4803 .log_details = btf_decl_tag_log,
4804 .show = btf_df_show,
4805};
4806
4807static int btf_func_proto_check(struct btf_verifier_env *env,
4808 const struct btf_type *t)
4809{
4810 const struct btf_type *ret_type;
4811 const struct btf_param *args;
4812 const struct btf *btf;
4813 u16 nr_args, i;
4814 int err;
4815
4816 btf = env->btf;
4817 args = (const struct btf_param *)(t + 1);
4818 nr_args = btf_type_vlen(t);
4819
4820 /* Check func return type which could be "void" (t->type == 0) */
4821 if (t->type) {
4822 u32 ret_type_id = t->type;
4823
4824 ret_type = btf_type_by_id(btf, ret_type_id);
4825 if (!ret_type) {
4826 btf_verifier_log_type(env, t, "Invalid return type");
4827 return -EINVAL;
4828 }
4829
4830 if (btf_type_is_resolve_source_only(ret_type)) {
4831 btf_verifier_log_type(env, t, "Invalid return type");
4832 return -EINVAL;
4833 }
4834
4835 if (btf_type_needs_resolve(ret_type) &&
4836 !env_type_is_resolved(env, ret_type_id)) {
4837 err = btf_resolve(env, ret_type, ret_type_id);
4838 if (err)
4839 return err;
4840 }
4841
4842 /* Ensure the return type is a type that has a size */
4843 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
4844 btf_verifier_log_type(env, t, "Invalid return type");
4845 return -EINVAL;
4846 }
4847 }
4848
4849 if (!nr_args)
4850 return 0;
4851
4852 /* Last func arg type_id could be 0 if it is a vararg */
4853 if (!args[nr_args - 1].type) {
4854 if (args[nr_args - 1].name_off) {
4855 btf_verifier_log_type(env, t, "Invalid arg#%u",
4856 nr_args);
4857 return -EINVAL;
4858 }
4859 nr_args--;
4860 }
4861
4862 for (i = 0; i < nr_args; i++) {
4863 const struct btf_type *arg_type;
4864 u32 arg_type_id;
4865
4866 arg_type_id = args[i].type;
4867 arg_type = btf_type_by_id(btf, arg_type_id);
4868 if (!arg_type) {
4869 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4870 return -EINVAL;
4871 }
4872
4873 if (btf_type_is_resolve_source_only(arg_type)) {
4874 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4875 return -EINVAL;
4876 }
4877
4878 if (args[i].name_off &&
4879 (!btf_name_offset_valid(btf, args[i].name_off) ||
4880 !btf_name_valid_identifier(btf, args[i].name_off))) {
4881 btf_verifier_log_type(env, t,
4882 "Invalid arg#%u", i + 1);
4883 return -EINVAL;
4884 }
4885
4886 if (btf_type_needs_resolve(arg_type) &&
4887 !env_type_is_resolved(env, arg_type_id)) {
4888 err = btf_resolve(env, arg_type, arg_type_id);
4889 if (err)
4890 return err;
4891 }
4892
4893 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4894 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4895 return -EINVAL;
4896 }
4897 }
4898
4899 return 0;
4900}
4901
4902static int btf_func_check(struct btf_verifier_env *env,
4903 const struct btf_type *t)
4904{
4905 const struct btf_type *proto_type;
4906 const struct btf_param *args;
4907 const struct btf *btf;
4908 u16 nr_args, i;
4909
4910 btf = env->btf;
4911 proto_type = btf_type_by_id(btf, t->type);
4912
4913 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4914 btf_verifier_log_type(env, t, "Invalid type_id");
4915 return -EINVAL;
4916 }
4917
4918 args = (const struct btf_param *)(proto_type + 1);
4919 nr_args = btf_type_vlen(proto_type);
4920 for (i = 0; i < nr_args; i++) {
4921 if (!args[i].name_off && args[i].type) {
4922 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4923 return -EINVAL;
4924 }
4925 }
4926
4927 return 0;
4928}
4929
4930static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4931 [BTF_KIND_INT] = &int_ops,
4932 [BTF_KIND_PTR] = &ptr_ops,
4933 [BTF_KIND_ARRAY] = &array_ops,
4934 [BTF_KIND_STRUCT] = &struct_ops,
4935 [BTF_KIND_UNION] = &struct_ops,
4936 [BTF_KIND_ENUM] = &enum_ops,
4937 [BTF_KIND_FWD] = &fwd_ops,
4938 [BTF_KIND_TYPEDEF] = &modifier_ops,
4939 [BTF_KIND_VOLATILE] = &modifier_ops,
4940 [BTF_KIND_CONST] = &modifier_ops,
4941 [BTF_KIND_RESTRICT] = &modifier_ops,
4942 [BTF_KIND_FUNC] = &func_ops,
4943 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
4944 [BTF_KIND_VAR] = &var_ops,
4945 [BTF_KIND_DATASEC] = &datasec_ops,
4946 [BTF_KIND_FLOAT] = &float_ops,
4947 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
4948 [BTF_KIND_TYPE_TAG] = &modifier_ops,
4949 [BTF_KIND_ENUM64] = &enum64_ops,
4950};
4951
4952static s32 btf_check_meta(struct btf_verifier_env *env,
4953 const struct btf_type *t,
4954 u32 meta_left)
4955{
4956 u32 saved_meta_left = meta_left;
4957 s32 var_meta_size;
4958
4959 if (meta_left < sizeof(*t)) {
4960 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
4961 env->log_type_id, meta_left, sizeof(*t));
4962 return -EINVAL;
4963 }
4964 meta_left -= sizeof(*t);
4965
4966 if (t->info & ~BTF_INFO_MASK) {
4967 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
4968 env->log_type_id, t->info);
4969 return -EINVAL;
4970 }
4971
4972 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
4973 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
4974 btf_verifier_log(env, "[%u] Invalid kind:%u",
4975 env->log_type_id, BTF_INFO_KIND(t->info));
4976 return -EINVAL;
4977 }
4978
4979 if (!btf_name_offset_valid(env->btf, t->name_off)) {
4980 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
4981 env->log_type_id, t->name_off);
4982 return -EINVAL;
4983 }
4984
4985 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
4986 if (var_meta_size < 0)
4987 return var_meta_size;
4988
4989 meta_left -= var_meta_size;
4990
4991 return saved_meta_left - meta_left;
4992}
4993
4994static int btf_check_all_metas(struct btf_verifier_env *env)
4995{
4996 struct btf *btf = env->btf;
4997 struct btf_header *hdr;
4998 void *cur, *end;
4999
5000 hdr = &btf->hdr;
5001 cur = btf->nohdr_data + hdr->type_off;
5002 end = cur + hdr->type_len;
5003
5004 env->log_type_id = btf->base_btf ? btf->start_id : 1;
5005 while (cur < end) {
5006 struct btf_type *t = cur;
5007 s32 meta_size;
5008
5009 meta_size = btf_check_meta(env, t, end - cur);
5010 if (meta_size < 0)
5011 return meta_size;
5012
5013 btf_add_type(env, t);
5014 cur += meta_size;
5015 env->log_type_id++;
5016 }
5017
5018 return 0;
5019}
5020
5021static bool btf_resolve_valid(struct btf_verifier_env *env,
5022 const struct btf_type *t,
5023 u32 type_id)
5024{
5025 struct btf *btf = env->btf;
5026
5027 if (!env_type_is_resolved(env, type_id))
5028 return false;
5029
5030 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
5031 return !btf_resolved_type_id(btf, type_id) &&
5032 !btf_resolved_type_size(btf, type_id);
5033
5034 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
5035 return btf_resolved_type_id(btf, type_id) &&
5036 !btf_resolved_type_size(btf, type_id);
5037
5038 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
5039 btf_type_is_var(t)) {
5040 t = btf_type_id_resolve(btf, &type_id);
5041 return t &&
5042 !btf_type_is_modifier(t) &&
5043 !btf_type_is_var(t) &&
5044 !btf_type_is_datasec(t);
5045 }
5046
5047 if (btf_type_is_array(t)) {
5048 const struct btf_array *array = btf_type_array(t);
5049 const struct btf_type *elem_type;
5050 u32 elem_type_id = array->type;
5051 u32 elem_size;
5052
5053 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
5054 return elem_type && !btf_type_is_modifier(elem_type) &&
5055 (array->nelems * elem_size ==
5056 btf_resolved_type_size(btf, type_id));
5057 }
5058
5059 return false;
5060}
5061
5062static int btf_resolve(struct btf_verifier_env *env,
5063 const struct btf_type *t, u32 type_id)
5064{
5065 u32 save_log_type_id = env->log_type_id;
5066 const struct resolve_vertex *v;
5067 int err = 0;
5068
5069 env->resolve_mode = RESOLVE_TBD;
5070 env_stack_push(env, t, type_id);
5071 while (!err && (v = env_stack_peak(env))) {
5072 env->log_type_id = v->type_id;
5073 err = btf_type_ops(v->t)->resolve(env, v);
5074 }
5075
5076 env->log_type_id = type_id;
5077 if (err == -E2BIG) {
5078 btf_verifier_log_type(env, t,
5079 "Exceeded max resolving depth:%u",
5080 MAX_RESOLVE_DEPTH);
5081 } else if (err == -EEXIST) {
5082 btf_verifier_log_type(env, t, "Loop detected");
5083 }
5084
5085 /* Final sanity check */
5086 if (!err && !btf_resolve_valid(env, t, type_id)) {
5087 btf_verifier_log_type(env, t, "Invalid resolve state");
5088 err = -EINVAL;
5089 }
5090
5091 env->log_type_id = save_log_type_id;
5092 return err;
5093}
5094
5095static int btf_check_all_types(struct btf_verifier_env *env)
5096{
5097 struct btf *btf = env->btf;
5098 const struct btf_type *t;
5099 u32 type_id, i;
5100 int err;
5101
5102 err = env_resolve_init(env);
5103 if (err)
5104 return err;
5105
5106 env->phase++;
5107 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
5108 type_id = btf->start_id + i;
5109 t = btf_type_by_id(btf, type_id);
5110
5111 env->log_type_id = type_id;
5112 if (btf_type_needs_resolve(t) &&
5113 !env_type_is_resolved(env, type_id)) {
5114 err = btf_resolve(env, t, type_id);
5115 if (err)
5116 return err;
5117 }
5118
5119 if (btf_type_is_func_proto(t)) {
5120 err = btf_func_proto_check(env, t);
5121 if (err)
5122 return err;
5123 }
5124 }
5125
5126 return 0;
5127}
5128
5129static int btf_parse_type_sec(struct btf_verifier_env *env)
5130{
5131 const struct btf_header *hdr = &env->btf->hdr;
5132 int err;
5133
5134 /* Type section must align to 4 bytes */
5135 if (hdr->type_off & (sizeof(u32) - 1)) {
5136 btf_verifier_log(env, "Unaligned type_off");
5137 return -EINVAL;
5138 }
5139
5140 if (!env->btf->base_btf && !hdr->type_len) {
5141 btf_verifier_log(env, "No type found");
5142 return -EINVAL;
5143 }
5144
5145 err = btf_check_all_metas(env);
5146 if (err)
5147 return err;
5148
5149 return btf_check_all_types(env);
5150}
5151
5152static int btf_parse_str_sec(struct btf_verifier_env *env)
5153{
5154 const struct btf_header *hdr;
5155 struct btf *btf = env->btf;
5156 const char *start, *end;
5157
5158 hdr = &btf->hdr;
5159 start = btf->nohdr_data + hdr->str_off;
5160 end = start + hdr->str_len;
5161
5162 if (end != btf->data + btf->data_size) {
5163 btf_verifier_log(env, "String section is not at the end");
5164 return -EINVAL;
5165 }
5166
5167 btf->strings = start;
5168
5169 if (btf->base_btf && !hdr->str_len)
5170 return 0;
5171 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
5172 btf_verifier_log(env, "Invalid string section");
5173 return -EINVAL;
5174 }
5175 if (!btf->base_btf && start[0]) {
5176 btf_verifier_log(env, "Invalid string section");
5177 return -EINVAL;
5178 }
5179
5180 return 0;
5181}
5182
5183static const size_t btf_sec_info_offset[] = {
5184 offsetof(struct btf_header, type_off),
5185 offsetof(struct btf_header, str_off),
5186};
5187
5188static int btf_sec_info_cmp(const void *a, const void *b)
5189{
5190 const struct btf_sec_info *x = a;
5191 const struct btf_sec_info *y = b;
5192
5193 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
5194}
5195
5196static int btf_check_sec_info(struct btf_verifier_env *env,
5197 u32 btf_data_size)
5198{
5199 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
5200 u32 total, expected_total, i;
5201 const struct btf_header *hdr;
5202 const struct btf *btf;
5203
5204 btf = env->btf;
5205 hdr = &btf->hdr;
5206
5207 /* Populate the secs from hdr */
5208 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
5209 secs[i] = *(struct btf_sec_info *)((void *)hdr +
5210 btf_sec_info_offset[i]);
5211
5212 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
5213 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
5214
5215 /* Check for gaps and overlap among sections */
5216 total = 0;
5217 expected_total = btf_data_size - hdr->hdr_len;
5218 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
5219 if (expected_total < secs[i].off) {
5220 btf_verifier_log(env, "Invalid section offset");
5221 return -EINVAL;
5222 }
5223 if (total < secs[i].off) {
5224 /* gap */
5225 btf_verifier_log(env, "Unsupported section found");
5226 return -EINVAL;
5227 }
5228 if (total > secs[i].off) {
5229 btf_verifier_log(env, "Section overlap found");
5230 return -EINVAL;
5231 }
5232 if (expected_total - total < secs[i].len) {
5233 btf_verifier_log(env,
5234 "Total section length too long");
5235 return -EINVAL;
5236 }
5237 total += secs[i].len;
5238 }
5239
5240 /* There is data other than hdr and known sections */
5241 if (expected_total != total) {
5242 btf_verifier_log(env, "Unsupported section found");
5243 return -EINVAL;
5244 }
5245
5246 return 0;
5247}
5248
5249static int btf_parse_hdr(struct btf_verifier_env *env)
5250{
5251 u32 hdr_len, hdr_copy, btf_data_size;
5252 const struct btf_header *hdr;
5253 struct btf *btf;
5254
5255 btf = env->btf;
5256 btf_data_size = btf->data_size;
5257
5258 if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
5259 btf_verifier_log(env, "hdr_len not found");
5260 return -EINVAL;
5261 }
5262
5263 hdr = btf->data;
5264 hdr_len = hdr->hdr_len;
5265 if (btf_data_size < hdr_len) {
5266 btf_verifier_log(env, "btf_header not found");
5267 return -EINVAL;
5268 }
5269
5270 /* Ensure the unsupported header fields are zero */
5271 if (hdr_len > sizeof(btf->hdr)) {
5272 u8 *expected_zero = btf->data + sizeof(btf->hdr);
5273 u8 *end = btf->data + hdr_len;
5274
5275 for (; expected_zero < end; expected_zero++) {
5276 if (*expected_zero) {
5277 btf_verifier_log(env, "Unsupported btf_header");
5278 return -E2BIG;
5279 }
5280 }
5281 }
5282
5283 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
5284 memcpy(&btf->hdr, btf->data, hdr_copy);
5285
5286 hdr = &btf->hdr;
5287
5288 btf_verifier_log_hdr(env, btf_data_size);
5289
5290 if (hdr->magic != BTF_MAGIC) {
5291 btf_verifier_log(env, "Invalid magic");
5292 return -EINVAL;
5293 }
5294
5295 if (hdr->version != BTF_VERSION) {
5296 btf_verifier_log(env, "Unsupported version");
5297 return -ENOTSUPP;
5298 }
5299
5300 if (hdr->flags) {
5301 btf_verifier_log(env, "Unsupported flags");
5302 return -ENOTSUPP;
5303 }
5304
5305 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
5306 btf_verifier_log(env, "No data");
5307 return -EINVAL;
5308 }
5309
5310 return btf_check_sec_info(env, btf_data_size);
5311}
5312
5313static const char *alloc_obj_fields[] = {
5314 "bpf_spin_lock",
5315 "bpf_list_head",
5316 "bpf_list_node",
5317 "bpf_rb_root",
5318 "bpf_rb_node",
5319 "bpf_refcount",
5320};
5321
5322static struct btf_struct_metas *
5323btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
5324{
5325 union {
5326 struct btf_id_set set;
5327 struct {
5328 u32 _cnt;
5329 u32 _ids[ARRAY_SIZE(alloc_obj_fields)];
5330 } _arr;
5331 } aof;
5332 struct btf_struct_metas *tab = NULL;
5333 int i, n, id, ret;
5334
5335 BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
5336 BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
5337
5338 memset(&aof, 0, sizeof(aof));
5339 for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
5340 /* Try to find whether this special type exists in user BTF, and
5341 * if so remember its ID so we can easily find it among members
5342 * of structs that we iterate in the next loop.
5343 */
5344 id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
5345 if (id < 0)
5346 continue;
5347 aof.set.ids[aof.set.cnt++] = id;
5348 }
5349
5350 if (!aof.set.cnt)
5351 return NULL;
5352 sort(&aof.set.ids, aof.set.cnt, sizeof(aof.set.ids[0]), btf_id_cmp_func, NULL);
5353
5354 n = btf_nr_types(btf);
5355 for (i = 1; i < n; i++) {
5356 struct btf_struct_metas *new_tab;
5357 const struct btf_member *member;
5358 struct btf_struct_meta *type;
5359 struct btf_record *record;
5360 const struct btf_type *t;
5361 int j, tab_cnt;
5362
5363 t = btf_type_by_id(btf, i);
5364 if (!t) {
5365 ret = -EINVAL;
5366 goto free;
5367 }
5368 if (!__btf_type_is_struct(t))
5369 continue;
5370
5371 cond_resched();
5372
5373 for_each_member(j, t, member) {
5374 if (btf_id_set_contains(&aof.set, member->type))
5375 goto parse;
5376 }
5377 continue;
5378 parse:
5379 tab_cnt = tab ? tab->cnt : 0;
5380 new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),
5381 GFP_KERNEL | __GFP_NOWARN);
5382 if (!new_tab) {
5383 ret = -ENOMEM;
5384 goto free;
5385 }
5386 if (!tab)
5387 new_tab->cnt = 0;
5388 tab = new_tab;
5389
5390 type = &tab->types[tab->cnt];
5391 type->btf_id = i;
5392 record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE |
5393 BPF_RB_ROOT | BPF_RB_NODE | BPF_REFCOUNT, t->size);
5394 /* The record cannot be unset, treat it as an error if so */
5395 if (IS_ERR_OR_NULL(record)) {
5396 ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
5397 goto free;
5398 }
5399 type->record = record;
5400 tab->cnt++;
5401 }
5402 return tab;
5403free:
5404 btf_struct_metas_free(tab);
5405 return ERR_PTR(ret);
5406}
5407
5408struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
5409{
5410 struct btf_struct_metas *tab;
5411
5412 BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
5413 tab = btf->struct_meta_tab;
5414 if (!tab)
5415 return NULL;
5416 return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
5417}
5418
5419static int btf_check_type_tags(struct btf_verifier_env *env,
5420 struct btf *btf, int start_id)
5421{
5422 int i, n, good_id = start_id - 1;
5423 bool in_tags;
5424
5425 n = btf_nr_types(btf);
5426 for (i = start_id; i < n; i++) {
5427 const struct btf_type *t;
5428 int chain_limit = 32;
5429 u32 cur_id = i;
5430
5431 t = btf_type_by_id(btf, i);
5432 if (!t)
5433 return -EINVAL;
5434 if (!btf_type_is_modifier(t))
5435 continue;
5436
5437 cond_resched();
5438
5439 in_tags = btf_type_is_type_tag(t);
5440 while (btf_type_is_modifier(t)) {
5441 if (!chain_limit--) {
5442 btf_verifier_log(env, "Max chain length or cycle detected");
5443 return -ELOOP;
5444 }
5445 if (btf_type_is_type_tag(t)) {
5446 if (!in_tags) {
5447 btf_verifier_log(env, "Type tags don't precede modifiers");
5448 return -EINVAL;
5449 }
5450 } else if (in_tags) {
5451 in_tags = false;
5452 }
5453 if (cur_id <= good_id)
5454 break;
5455 /* Move to next type */
5456 cur_id = t->type;
5457 t = btf_type_by_id(btf, cur_id);
5458 if (!t)
5459 return -EINVAL;
5460 }
5461 good_id = i;
5462 }
5463 return 0;
5464}
5465
5466static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
5467{
5468 u32 log_true_size;
5469 int err;
5470
5471 err = bpf_vlog_finalize(log, &log_true_size);
5472
5473 if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
5474 copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
5475 &log_true_size, sizeof(log_true_size)))
5476 err = -EFAULT;
5477
5478 return err;
5479}
5480
5481static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
5482{
5483 bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
5484 char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
5485 struct btf_struct_metas *struct_meta_tab;
5486 struct btf_verifier_env *env = NULL;
5487 struct btf *btf = NULL;
5488 u8 *data;
5489 int err, ret;
5490
5491 if (attr->btf_size > BTF_MAX_SIZE)
5492 return ERR_PTR(-E2BIG);
5493
5494 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5495 if (!env)
5496 return ERR_PTR(-ENOMEM);
5497
5498 /* user could have requested verbose verifier output
5499 * and supplied buffer to store the verification trace
5500 */
5501 err = bpf_vlog_init(&env->log, attr->btf_log_level,
5502 log_ubuf, attr->btf_log_size);
5503 if (err)
5504 goto errout_free;
5505
5506 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5507 if (!btf) {
5508 err = -ENOMEM;
5509 goto errout;
5510 }
5511 env->btf = btf;
5512
5513 data = kvmalloc(attr->btf_size, GFP_KERNEL | __GFP_NOWARN);
5514 if (!data) {
5515 err = -ENOMEM;
5516 goto errout;
5517 }
5518
5519 btf->data = data;
5520 btf->data_size = attr->btf_size;
5521
5522 if (copy_from_bpfptr(data, btf_data, attr->btf_size)) {
5523 err = -EFAULT;
5524 goto errout;
5525 }
5526
5527 err = btf_parse_hdr(env);
5528 if (err)
5529 goto errout;
5530
5531 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5532
5533 err = btf_parse_str_sec(env);
5534 if (err)
5535 goto errout;
5536
5537 err = btf_parse_type_sec(env);
5538 if (err)
5539 goto errout;
5540
5541 err = btf_check_type_tags(env, btf, 1);
5542 if (err)
5543 goto errout;
5544
5545 struct_meta_tab = btf_parse_struct_metas(&env->log, btf);
5546 if (IS_ERR(struct_meta_tab)) {
5547 err = PTR_ERR(struct_meta_tab);
5548 goto errout;
5549 }
5550 btf->struct_meta_tab = struct_meta_tab;
5551
5552 if (struct_meta_tab) {
5553 int i;
5554
5555 for (i = 0; i < struct_meta_tab->cnt; i++) {
5556 err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
5557 if (err < 0)
5558 goto errout_meta;
5559 }
5560 }
5561
5562 err = finalize_log(&env->log, uattr, uattr_size);
5563 if (err)
5564 goto errout_free;
5565
5566 btf_verifier_env_free(env);
5567 refcount_set(&btf->refcnt, 1);
5568 return btf;
5569
5570errout_meta:
5571 btf_free_struct_meta_tab(btf);
5572errout:
5573 /* overwrite err with -ENOSPC or -EFAULT */
5574 ret = finalize_log(&env->log, uattr, uattr_size);
5575 if (ret)
5576 err = ret;
5577errout_free:
5578 btf_verifier_env_free(env);
5579 if (btf)
5580 btf_free(btf);
5581 return ERR_PTR(err);
5582}
5583
5584extern char __weak __start_BTF[];
5585extern char __weak __stop_BTF[];
5586extern struct btf *btf_vmlinux;
5587
5588#define BPF_MAP_TYPE(_id, _ops)
5589#define BPF_LINK_TYPE(_id, _name)
5590static union {
5591 struct bpf_ctx_convert {
5592#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5593 prog_ctx_type _id##_prog; \
5594 kern_ctx_type _id##_kern;
5595#include <linux/bpf_types.h>
5596#undef BPF_PROG_TYPE
5597 } *__t;
5598 /* 't' is written once under lock. Read many times. */
5599 const struct btf_type *t;
5600} bpf_ctx_convert;
5601enum {
5602#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5603 __ctx_convert##_id,
5604#include <linux/bpf_types.h>
5605#undef BPF_PROG_TYPE
5606 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
5607};
5608static u8 bpf_ctx_convert_map[] = {
5609#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5610 [_id] = __ctx_convert##_id,
5611#include <linux/bpf_types.h>
5612#undef BPF_PROG_TYPE
5613 0, /* avoid empty array */
5614};
5615#undef BPF_MAP_TYPE
5616#undef BPF_LINK_TYPE
5617
5618static const struct btf_type *find_canonical_prog_ctx_type(enum bpf_prog_type prog_type)
5619{
5620 const struct btf_type *conv_struct;
5621 const struct btf_member *ctx_type;
5622
5623 conv_struct = bpf_ctx_convert.t;
5624 if (!conv_struct)
5625 return NULL;
5626 /* prog_type is valid bpf program type. No need for bounds check. */
5627 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5628 /* ctx_type is a pointer to prog_ctx_type in vmlinux.
5629 * Like 'struct __sk_buff'
5630 */
5631 return btf_type_by_id(btf_vmlinux, ctx_type->type);
5632}
5633
5634static int find_kern_ctx_type_id(enum bpf_prog_type prog_type)
5635{
5636 const struct btf_type *conv_struct;
5637 const struct btf_member *ctx_type;
5638
5639 conv_struct = bpf_ctx_convert.t;
5640 if (!conv_struct)
5641 return -EFAULT;
5642 /* prog_type is valid bpf program type. No need for bounds check. */
5643 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5644 /* ctx_type is a pointer to prog_ctx_type in vmlinux.
5645 * Like 'struct sk_buff'
5646 */
5647 return ctx_type->type;
5648}
5649
5650const struct btf_type *
5651btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5652 const struct btf_type *t, enum bpf_prog_type prog_type,
5653 int arg)
5654{
5655 const struct btf_type *ctx_type;
5656 const char *tname, *ctx_tname;
5657
5658 t = btf_type_by_id(btf, t->type);
5659 while (btf_type_is_modifier(t))
5660 t = btf_type_by_id(btf, t->type);
5661 if (!btf_type_is_struct(t)) {
5662 /* Only pointer to struct is supported for now.
5663 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5664 * is not supported yet.
5665 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5666 */
5667 return NULL;
5668 }
5669 tname = btf_name_by_offset(btf, t->name_off);
5670 if (!tname) {
5671 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5672 return NULL;
5673 }
5674
5675 ctx_type = find_canonical_prog_ctx_type(prog_type);
5676 if (!ctx_type) {
5677 bpf_log(log, "btf_vmlinux is malformed\n");
5678 /* should not happen */
5679 return NULL;
5680 }
5681again:
5682 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5683 if (!ctx_tname) {
5684 /* should not happen */
5685 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
5686 return NULL;
5687 }
5688 /* only compare that prog's ctx type name is the same as
5689 * kernel expects. No need to compare field by field.
5690 * It's ok for bpf prog to do:
5691 * struct __sk_buff {};
5692 * int socket_filter_bpf_prog(struct __sk_buff *skb)
5693 * { // no fields of skb are ever used }
5694 */
5695 if (strcmp(ctx_tname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0)
5696 return ctx_type;
5697 if (strcmp(ctx_tname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0)
5698 return ctx_type;
5699 if (strcmp(ctx_tname, tname)) {
5700 /* bpf_user_pt_regs_t is a typedef, so resolve it to
5701 * underlying struct and check name again
5702 */
5703 if (!btf_type_is_modifier(ctx_type))
5704 return NULL;
5705 while (btf_type_is_modifier(ctx_type))
5706 ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
5707 goto again;
5708 }
5709 return ctx_type;
5710}
5711
5712/* forward declarations for arch-specific underlying types of
5713 * bpf_user_pt_regs_t; this avoids the need for arch-specific #ifdef
5714 * compilation guards below for BPF_PROG_TYPE_PERF_EVENT checks, but still
5715 * works correctly with __builtin_types_compatible_p() on respective
5716 * architectures
5717 */
5718struct user_regs_struct;
5719struct user_pt_regs;
5720
5721static int btf_validate_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5722 const struct btf_type *t, int arg,
5723 enum bpf_prog_type prog_type,
5724 enum bpf_attach_type attach_type)
5725{
5726 const struct btf_type *ctx_type;
5727 const char *tname, *ctx_tname;
5728
5729 if (!btf_is_ptr(t)) {
5730 bpf_log(log, "arg#%d type isn't a pointer\n", arg);
5731 return -EINVAL;
5732 }
5733 t = btf_type_by_id(btf, t->type);
5734
5735 /* KPROBE and PERF_EVENT programs allow bpf_user_pt_regs_t typedef */
5736 if (prog_type == BPF_PROG_TYPE_KPROBE || prog_type == BPF_PROG_TYPE_PERF_EVENT) {
5737 while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
5738 t = btf_type_by_id(btf, t->type);
5739
5740 if (btf_type_is_typedef(t)) {
5741 tname = btf_name_by_offset(btf, t->name_off);
5742 if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
5743 return 0;
5744 }
5745 }
5746
5747 /* all other program types don't use typedefs for context type */
5748 while (btf_type_is_modifier(t))
5749 t = btf_type_by_id(btf, t->type);
5750
5751 /* `void *ctx __arg_ctx` is always valid */
5752 if (btf_type_is_void(t))
5753 return 0;
5754
5755 tname = btf_name_by_offset(btf, t->name_off);
5756 if (str_is_empty(tname)) {
5757 bpf_log(log, "arg#%d type doesn't have a name\n", arg);
5758 return -EINVAL;
5759 }
5760
5761 /* special cases */
5762 switch (prog_type) {
5763 case BPF_PROG_TYPE_KPROBE:
5764 if (__btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
5765 return 0;
5766 break;
5767 case BPF_PROG_TYPE_PERF_EVENT:
5768 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) &&
5769 __btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
5770 return 0;
5771 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) &&
5772 __btf_type_is_struct(t) && strcmp(tname, "user_pt_regs") == 0)
5773 return 0;
5774 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) &&
5775 __btf_type_is_struct(t) && strcmp(tname, "user_regs_struct") == 0)
5776 return 0;
5777 break;
5778 case BPF_PROG_TYPE_RAW_TRACEPOINT:
5779 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
5780 /* allow u64* as ctx */
5781 if (btf_is_int(t) && t->size == 8)
5782 return 0;
5783 break;
5784 case BPF_PROG_TYPE_TRACING:
5785 switch (attach_type) {
5786 case BPF_TRACE_RAW_TP:
5787 /* tp_btf program is TRACING, so need special case here */
5788 if (__btf_type_is_struct(t) &&
5789 strcmp(tname, "bpf_raw_tracepoint_args") == 0)
5790 return 0;
5791 /* allow u64* as ctx */
5792 if (btf_is_int(t) && t->size == 8)
5793 return 0;
5794 break;
5795 case BPF_TRACE_ITER:
5796 /* allow struct bpf_iter__xxx types only */
5797 if (__btf_type_is_struct(t) &&
5798 strncmp(tname, "bpf_iter__", sizeof("bpf_iter__") - 1) == 0)
5799 return 0;
5800 break;
5801 case BPF_TRACE_FENTRY:
5802 case BPF_TRACE_FEXIT:
5803 case BPF_MODIFY_RETURN:
5804 /* allow u64* as ctx */
5805 if (btf_is_int(t) && t->size == 8)
5806 return 0;
5807 break;
5808 default:
5809 break;
5810 }
5811 break;
5812 case BPF_PROG_TYPE_LSM:
5813 case BPF_PROG_TYPE_STRUCT_OPS:
5814 /* allow u64* as ctx */
5815 if (btf_is_int(t) && t->size == 8)
5816 return 0;
5817 break;
5818 case BPF_PROG_TYPE_TRACEPOINT:
5819 case BPF_PROG_TYPE_SYSCALL:
5820 case BPF_PROG_TYPE_EXT:
5821 return 0; /* anything goes */
5822 default:
5823 break;
5824 }
5825
5826 ctx_type = find_canonical_prog_ctx_type(prog_type);
5827 if (!ctx_type) {
5828 /* should not happen */
5829 bpf_log(log, "btf_vmlinux is malformed\n");
5830 return -EINVAL;
5831 }
5832
5833 /* resolve typedefs and check that underlying structs are matching as well */
5834 while (btf_type_is_modifier(ctx_type))
5835 ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
5836
5837 /* if program type doesn't have distinctly named struct type for
5838 * context, then __arg_ctx argument can only be `void *`, which we
5839 * already checked above
5840 */
5841 if (!__btf_type_is_struct(ctx_type)) {
5842 bpf_log(log, "arg#%d should be void pointer\n", arg);
5843 return -EINVAL;
5844 }
5845
5846 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5847 if (!__btf_type_is_struct(t) || strcmp(ctx_tname, tname) != 0) {
5848 bpf_log(log, "arg#%d should be `struct %s *`\n", arg, ctx_tname);
5849 return -EINVAL;
5850 }
5851
5852 return 0;
5853}
5854
5855static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
5856 struct btf *btf,
5857 const struct btf_type *t,
5858 enum bpf_prog_type prog_type,
5859 int arg)
5860{
5861 if (!btf_get_prog_ctx_type(log, btf, t, prog_type, arg))
5862 return -ENOENT;
5863 return find_kern_ctx_type_id(prog_type);
5864}
5865
5866int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type)
5867{
5868 const struct btf_member *kctx_member;
5869 const struct btf_type *conv_struct;
5870 const struct btf_type *kctx_type;
5871 u32 kctx_type_id;
5872
5873 conv_struct = bpf_ctx_convert.t;
5874 /* get member for kernel ctx type */
5875 kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5876 kctx_type_id = kctx_member->type;
5877 kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id);
5878 if (!btf_type_is_struct(kctx_type)) {
5879 bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id);
5880 return -EINVAL;
5881 }
5882
5883 return kctx_type_id;
5884}
5885
5886BTF_ID_LIST(bpf_ctx_convert_btf_id)
5887BTF_ID(struct, bpf_ctx_convert)
5888
5889struct btf *btf_parse_vmlinux(void)
5890{
5891 struct btf_verifier_env *env = NULL;
5892 struct bpf_verifier_log *log;
5893 struct btf *btf = NULL;
5894 int err;
5895
5896 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5897 if (!env)
5898 return ERR_PTR(-ENOMEM);
5899
5900 log = &env->log;
5901 log->level = BPF_LOG_KERNEL;
5902
5903 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5904 if (!btf) {
5905 err = -ENOMEM;
5906 goto errout;
5907 }
5908 env->btf = btf;
5909
5910 btf->data = __start_BTF;
5911 btf->data_size = __stop_BTF - __start_BTF;
5912 btf->kernel_btf = true;
5913 snprintf(btf->name, sizeof(btf->name), "vmlinux");
5914
5915 err = btf_parse_hdr(env);
5916 if (err)
5917 goto errout;
5918
5919 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5920
5921 err = btf_parse_str_sec(env);
5922 if (err)
5923 goto errout;
5924
5925 err = btf_check_all_metas(env);
5926 if (err)
5927 goto errout;
5928
5929 err = btf_check_type_tags(env, btf, 1);
5930 if (err)
5931 goto errout;
5932
5933 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
5934 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
5935
5936 bpf_struct_ops_init(btf, log);
5937
5938 refcount_set(&btf->refcnt, 1);
5939
5940 err = btf_alloc_id(btf);
5941 if (err)
5942 goto errout;
5943
5944 btf_verifier_env_free(env);
5945 return btf;
5946
5947errout:
5948 btf_verifier_env_free(env);
5949 if (btf) {
5950 kvfree(btf->types);
5951 kfree(btf);
5952 }
5953 return ERR_PTR(err);
5954}
5955
5956#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
5957
5958static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
5959{
5960 struct btf_verifier_env *env = NULL;
5961 struct bpf_verifier_log *log;
5962 struct btf *btf = NULL, *base_btf;
5963 int err;
5964
5965 base_btf = bpf_get_btf_vmlinux();
5966 if (IS_ERR(base_btf))
5967 return base_btf;
5968 if (!base_btf)
5969 return ERR_PTR(-EINVAL);
5970
5971 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5972 if (!env)
5973 return ERR_PTR(-ENOMEM);
5974
5975 log = &env->log;
5976 log->level = BPF_LOG_KERNEL;
5977
5978 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5979 if (!btf) {
5980 err = -ENOMEM;
5981 goto errout;
5982 }
5983 env->btf = btf;
5984
5985 btf->base_btf = base_btf;
5986 btf->start_id = base_btf->nr_types;
5987 btf->start_str_off = base_btf->hdr.str_len;
5988 btf->kernel_btf = true;
5989 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
5990
5991 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
5992 if (!btf->data) {
5993 err = -ENOMEM;
5994 goto errout;
5995 }
5996 memcpy(btf->data, data, data_size);
5997 btf->data_size = data_size;
5998
5999 err = btf_parse_hdr(env);
6000 if (err)
6001 goto errout;
6002
6003 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6004
6005 err = btf_parse_str_sec(env);
6006 if (err)
6007 goto errout;
6008
6009 err = btf_check_all_metas(env);
6010 if (err)
6011 goto errout;
6012
6013 err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
6014 if (err)
6015 goto errout;
6016
6017 btf_verifier_env_free(env);
6018 refcount_set(&btf->refcnt, 1);
6019 return btf;
6020
6021errout:
6022 btf_verifier_env_free(env);
6023 if (btf) {
6024 kvfree(btf->data);
6025 kvfree(btf->types);
6026 kfree(btf);
6027 }
6028 return ERR_PTR(err);
6029}
6030
6031#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6032
6033struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
6034{
6035 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6036
6037 if (tgt_prog)
6038 return tgt_prog->aux->btf;
6039 else
6040 return prog->aux->attach_btf;
6041}
6042
6043static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
6044{
6045 /* skip modifiers */
6046 t = btf_type_skip_modifiers(btf, t->type, NULL);
6047
6048 return btf_type_is_int(t);
6049}
6050
6051static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
6052 int off)
6053{
6054 const struct btf_param *args;
6055 const struct btf_type *t;
6056 u32 offset = 0, nr_args;
6057 int i;
6058
6059 if (!func_proto)
6060 return off / 8;
6061
6062 nr_args = btf_type_vlen(func_proto);
6063 args = (const struct btf_param *)(func_proto + 1);
6064 for (i = 0; i < nr_args; i++) {
6065 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6066 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6067 if (off < offset)
6068 return i;
6069 }
6070
6071 t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
6072 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6073 if (off < offset)
6074 return nr_args;
6075
6076 return nr_args + 1;
6077}
6078
6079static bool prog_args_trusted(const struct bpf_prog *prog)
6080{
6081 enum bpf_attach_type atype = prog->expected_attach_type;
6082
6083 switch (prog->type) {
6084 case BPF_PROG_TYPE_TRACING:
6085 return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER;
6086 case BPF_PROG_TYPE_LSM:
6087 return bpf_lsm_is_trusted(prog);
6088 case BPF_PROG_TYPE_STRUCT_OPS:
6089 return true;
6090 default:
6091 return false;
6092 }
6093}
6094
6095bool btf_ctx_access(int off, int size, enum bpf_access_type type,
6096 const struct bpf_prog *prog,
6097 struct bpf_insn_access_aux *info)
6098{
6099 const struct btf_type *t = prog->aux->attach_func_proto;
6100 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6101 struct btf *btf = bpf_prog_get_target_btf(prog);
6102 const char *tname = prog->aux->attach_func_name;
6103 struct bpf_verifier_log *log = info->log;
6104 const struct btf_param *args;
6105 const char *tag_value;
6106 u32 nr_args, arg;
6107 int i, ret;
6108
6109 if (off % 8) {
6110 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
6111 tname, off);
6112 return false;
6113 }
6114 arg = get_ctx_arg_idx(btf, t, off);
6115 args = (const struct btf_param *)(t + 1);
6116 /* if (t == NULL) Fall back to default BPF prog with
6117 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
6118 */
6119 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
6120 if (prog->aux->attach_btf_trace) {
6121 /* skip first 'void *__data' argument in btf_trace_##name typedef */
6122 args++;
6123 nr_args--;
6124 }
6125
6126 if (arg > nr_args) {
6127 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6128 tname, arg + 1);
6129 return false;
6130 }
6131
6132 if (arg == nr_args) {
6133 switch (prog->expected_attach_type) {
6134 case BPF_LSM_CGROUP:
6135 case BPF_LSM_MAC:
6136 case BPF_TRACE_FEXIT:
6137 /* When LSM programs are attached to void LSM hooks
6138 * they use FEXIT trampolines and when attached to
6139 * int LSM hooks, they use MODIFY_RETURN trampolines.
6140 *
6141 * While the LSM programs are BPF_MODIFY_RETURN-like
6142 * the check:
6143 *
6144 * if (ret_type != 'int')
6145 * return -EINVAL;
6146 *
6147 * is _not_ done here. This is still safe as LSM hooks
6148 * have only void and int return types.
6149 */
6150 if (!t)
6151 return true;
6152 t = btf_type_by_id(btf, t->type);
6153 break;
6154 case BPF_MODIFY_RETURN:
6155 /* For now the BPF_MODIFY_RETURN can only be attached to
6156 * functions that return an int.
6157 */
6158 if (!t)
6159 return false;
6160
6161 t = btf_type_skip_modifiers(btf, t->type, NULL);
6162 if (!btf_type_is_small_int(t)) {
6163 bpf_log(log,
6164 "ret type %s not allowed for fmod_ret\n",
6165 btf_type_str(t));
6166 return false;
6167 }
6168 break;
6169 default:
6170 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6171 tname, arg + 1);
6172 return false;
6173 }
6174 } else {
6175 if (!t)
6176 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
6177 return true;
6178 t = btf_type_by_id(btf, args[arg].type);
6179 }
6180
6181 /* skip modifiers */
6182 while (btf_type_is_modifier(t))
6183 t = btf_type_by_id(btf, t->type);
6184 if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6185 /* accessing a scalar */
6186 return true;
6187 if (!btf_type_is_ptr(t)) {
6188 bpf_log(log,
6189 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
6190 tname, arg,
6191 __btf_name_by_offset(btf, t->name_off),
6192 btf_type_str(t));
6193 return false;
6194 }
6195
6196 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
6197 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6198 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6199 u32 type, flag;
6200
6201 type = base_type(ctx_arg_info->reg_type);
6202 flag = type_flag(ctx_arg_info->reg_type);
6203 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
6204 (flag & PTR_MAYBE_NULL)) {
6205 info->reg_type = ctx_arg_info->reg_type;
6206 return true;
6207 }
6208 }
6209
6210 if (t->type == 0)
6211 /* This is a pointer to void.
6212 * It is the same as scalar from the verifier safety pov.
6213 * No further pointer walking is allowed.
6214 */
6215 return true;
6216
6217 if (is_int_ptr(btf, t))
6218 return true;
6219
6220 /* this is a pointer to another type */
6221 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6222 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6223
6224 if (ctx_arg_info->offset == off) {
6225 if (!ctx_arg_info->btf_id) {
6226 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
6227 return false;
6228 }
6229
6230 info->reg_type = ctx_arg_info->reg_type;
6231 info->btf = btf_vmlinux;
6232 info->btf_id = ctx_arg_info->btf_id;
6233 return true;
6234 }
6235 }
6236
6237 info->reg_type = PTR_TO_BTF_ID;
6238 if (prog_args_trusted(prog))
6239 info->reg_type |= PTR_TRUSTED;
6240
6241 if (tgt_prog) {
6242 enum bpf_prog_type tgt_type;
6243
6244 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
6245 tgt_type = tgt_prog->aux->saved_dst_prog_type;
6246 else
6247 tgt_type = tgt_prog->type;
6248
6249 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
6250 if (ret > 0) {
6251 info->btf = btf_vmlinux;
6252 info->btf_id = ret;
6253 return true;
6254 } else {
6255 return false;
6256 }
6257 }
6258
6259 info->btf = btf;
6260 info->btf_id = t->type;
6261 t = btf_type_by_id(btf, t->type);
6262
6263 if (btf_type_is_type_tag(t)) {
6264 tag_value = __btf_name_by_offset(btf, t->name_off);
6265 if (strcmp(tag_value, "user") == 0)
6266 info->reg_type |= MEM_USER;
6267 if (strcmp(tag_value, "percpu") == 0)
6268 info->reg_type |= MEM_PERCPU;
6269 }
6270
6271 /* skip modifiers */
6272 while (btf_type_is_modifier(t)) {
6273 info->btf_id = t->type;
6274 t = btf_type_by_id(btf, t->type);
6275 }
6276 if (!btf_type_is_struct(t)) {
6277 bpf_log(log,
6278 "func '%s' arg%d type %s is not a struct\n",
6279 tname, arg, btf_type_str(t));
6280 return false;
6281 }
6282 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
6283 tname, arg, info->btf_id, btf_type_str(t),
6284 __btf_name_by_offset(btf, t->name_off));
6285 return true;
6286}
6287
6288enum bpf_struct_walk_result {
6289 /* < 0 error */
6290 WALK_SCALAR = 0,
6291 WALK_PTR,
6292 WALK_STRUCT,
6293};
6294
6295static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
6296 const struct btf_type *t, int off, int size,
6297 u32 *next_btf_id, enum bpf_type_flag *flag,
6298 const char **field_name)
6299{
6300 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
6301 const struct btf_type *mtype, *elem_type = NULL;
6302 const struct btf_member *member;
6303 const char *tname, *mname, *tag_value;
6304 u32 vlen, elem_id, mid;
6305
6306again:
6307 if (btf_type_is_modifier(t))
6308 t = btf_type_skip_modifiers(btf, t->type, NULL);
6309 tname = __btf_name_by_offset(btf, t->name_off);
6310 if (!btf_type_is_struct(t)) {
6311 bpf_log(log, "Type '%s' is not a struct\n", tname);
6312 return -EINVAL;
6313 }
6314
6315 vlen = btf_type_vlen(t);
6316 if (BTF_INFO_KIND(t->info) == BTF_KIND_UNION && vlen != 1 && !(*flag & PTR_UNTRUSTED))
6317 /*
6318 * walking unions yields untrusted pointers
6319 * with exception of __bpf_md_ptr and other
6320 * unions with a single member
6321 */
6322 *flag |= PTR_UNTRUSTED;
6323
6324 if (off + size > t->size) {
6325 /* If the last element is a variable size array, we may
6326 * need to relax the rule.
6327 */
6328 struct btf_array *array_elem;
6329
6330 if (vlen == 0)
6331 goto error;
6332
6333 member = btf_type_member(t) + vlen - 1;
6334 mtype = btf_type_skip_modifiers(btf, member->type,
6335 NULL);
6336 if (!btf_type_is_array(mtype))
6337 goto error;
6338
6339 array_elem = (struct btf_array *)(mtype + 1);
6340 if (array_elem->nelems != 0)
6341 goto error;
6342
6343 moff = __btf_member_bit_offset(t, member) / 8;
6344 if (off < moff)
6345 goto error;
6346
6347 /* allow structure and integer */
6348 t = btf_type_skip_modifiers(btf, array_elem->type,
6349 NULL);
6350
6351 if (btf_type_is_int(t))
6352 return WALK_SCALAR;
6353
6354 if (!btf_type_is_struct(t))
6355 goto error;
6356
6357 off = (off - moff) % t->size;
6358 goto again;
6359
6360error:
6361 bpf_log(log, "access beyond struct %s at off %u size %u\n",
6362 tname, off, size);
6363 return -EACCES;
6364 }
6365
6366 for_each_member(i, t, member) {
6367 /* offset of the field in bytes */
6368 moff = __btf_member_bit_offset(t, member) / 8;
6369 if (off + size <= moff)
6370 /* won't find anything, field is already too far */
6371 break;
6372
6373 if (__btf_member_bitfield_size(t, member)) {
6374 u32 end_bit = __btf_member_bit_offset(t, member) +
6375 __btf_member_bitfield_size(t, member);
6376
6377 /* off <= moff instead of off == moff because clang
6378 * does not generate a BTF member for anonymous
6379 * bitfield like the ":16" here:
6380 * struct {
6381 * int :16;
6382 * int x:8;
6383 * };
6384 */
6385 if (off <= moff &&
6386 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
6387 return WALK_SCALAR;
6388
6389 /* off may be accessing a following member
6390 *
6391 * or
6392 *
6393 * Doing partial access at either end of this
6394 * bitfield. Continue on this case also to
6395 * treat it as not accessing this bitfield
6396 * and eventually error out as field not
6397 * found to keep it simple.
6398 * It could be relaxed if there was a legit
6399 * partial access case later.
6400 */
6401 continue;
6402 }
6403
6404 /* In case of "off" is pointing to holes of a struct */
6405 if (off < moff)
6406 break;
6407
6408 /* type of the field */
6409 mid = member->type;
6410 mtype = btf_type_by_id(btf, member->type);
6411 mname = __btf_name_by_offset(btf, member->name_off);
6412
6413 mtype = __btf_resolve_size(btf, mtype, &msize,
6414 &elem_type, &elem_id, &total_nelems,
6415 &mid);
6416 if (IS_ERR(mtype)) {
6417 bpf_log(log, "field %s doesn't have size\n", mname);
6418 return -EFAULT;
6419 }
6420
6421 mtrue_end = moff + msize;
6422 if (off >= mtrue_end)
6423 /* no overlap with member, keep iterating */
6424 continue;
6425
6426 if (btf_type_is_array(mtype)) {
6427 u32 elem_idx;
6428
6429 /* __btf_resolve_size() above helps to
6430 * linearize a multi-dimensional array.
6431 *
6432 * The logic here is treating an array
6433 * in a struct as the following way:
6434 *
6435 * struct outer {
6436 * struct inner array[2][2];
6437 * };
6438 *
6439 * looks like:
6440 *
6441 * struct outer {
6442 * struct inner array_elem0;
6443 * struct inner array_elem1;
6444 * struct inner array_elem2;
6445 * struct inner array_elem3;
6446 * };
6447 *
6448 * When accessing outer->array[1][0], it moves
6449 * moff to "array_elem2", set mtype to
6450 * "struct inner", and msize also becomes
6451 * sizeof(struct inner). Then most of the
6452 * remaining logic will fall through without
6453 * caring the current member is an array or
6454 * not.
6455 *
6456 * Unlike mtype/msize/moff, mtrue_end does not
6457 * change. The naming difference ("_true") tells
6458 * that it is not always corresponding to
6459 * the current mtype/msize/moff.
6460 * It is the true end of the current
6461 * member (i.e. array in this case). That
6462 * will allow an int array to be accessed like
6463 * a scratch space,
6464 * i.e. allow access beyond the size of
6465 * the array's element as long as it is
6466 * within the mtrue_end boundary.
6467 */
6468
6469 /* skip empty array */
6470 if (moff == mtrue_end)
6471 continue;
6472
6473 msize /= total_nelems;
6474 elem_idx = (off - moff) / msize;
6475 moff += elem_idx * msize;
6476 mtype = elem_type;
6477 mid = elem_id;
6478 }
6479
6480 /* the 'off' we're looking for is either equal to start
6481 * of this field or inside of this struct
6482 */
6483 if (btf_type_is_struct(mtype)) {
6484 /* our field must be inside that union or struct */
6485 t = mtype;
6486
6487 /* return if the offset matches the member offset */
6488 if (off == moff) {
6489 *next_btf_id = mid;
6490 return WALK_STRUCT;
6491 }
6492
6493 /* adjust offset we're looking for */
6494 off -= moff;
6495 goto again;
6496 }
6497
6498 if (btf_type_is_ptr(mtype)) {
6499 const struct btf_type *stype, *t;
6500 enum bpf_type_flag tmp_flag = 0;
6501 u32 id;
6502
6503 if (msize != size || off != moff) {
6504 bpf_log(log,
6505 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
6506 mname, moff, tname, off, size);
6507 return -EACCES;
6508 }
6509
6510 /* check type tag */
6511 t = btf_type_by_id(btf, mtype->type);
6512 if (btf_type_is_type_tag(t)) {
6513 tag_value = __btf_name_by_offset(btf, t->name_off);
6514 /* check __user tag */
6515 if (strcmp(tag_value, "user") == 0)
6516 tmp_flag = MEM_USER;
6517 /* check __percpu tag */
6518 if (strcmp(tag_value, "percpu") == 0)
6519 tmp_flag = MEM_PERCPU;
6520 /* check __rcu tag */
6521 if (strcmp(tag_value, "rcu") == 0)
6522 tmp_flag = MEM_RCU;
6523 }
6524
6525 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
6526 if (btf_type_is_struct(stype)) {
6527 *next_btf_id = id;
6528 *flag |= tmp_flag;
6529 if (field_name)
6530 *field_name = mname;
6531 return WALK_PTR;
6532 }
6533 }
6534
6535 /* Allow more flexible access within an int as long as
6536 * it is within mtrue_end.
6537 * Since mtrue_end could be the end of an array,
6538 * that also allows using an array of int as a scratch
6539 * space. e.g. skb->cb[].
6540 */
6541 if (off + size > mtrue_end && !(*flag & PTR_UNTRUSTED)) {
6542 bpf_log(log,
6543 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
6544 mname, mtrue_end, tname, off, size);
6545 return -EACCES;
6546 }
6547
6548 return WALK_SCALAR;
6549 }
6550 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
6551 return -EINVAL;
6552}
6553
6554int btf_struct_access(struct bpf_verifier_log *log,
6555 const struct bpf_reg_state *reg,
6556 int off, int size, enum bpf_access_type atype __maybe_unused,
6557 u32 *next_btf_id, enum bpf_type_flag *flag,
6558 const char **field_name)
6559{
6560 const struct btf *btf = reg->btf;
6561 enum bpf_type_flag tmp_flag = 0;
6562 const struct btf_type *t;
6563 u32 id = reg->btf_id;
6564 int err;
6565
6566 while (type_is_alloc(reg->type)) {
6567 struct btf_struct_meta *meta;
6568 struct btf_record *rec;
6569 int i;
6570
6571 meta = btf_find_struct_meta(btf, id);
6572 if (!meta)
6573 break;
6574 rec = meta->record;
6575 for (i = 0; i < rec->cnt; i++) {
6576 struct btf_field *field = &rec->fields[i];
6577 u32 offset = field->offset;
6578 if (off < offset + btf_field_type_size(field->type) && offset < off + size) {
6579 bpf_log(log,
6580 "direct access to %s is disallowed\n",
6581 btf_field_type_name(field->type));
6582 return -EACCES;
6583 }
6584 }
6585 break;
6586 }
6587
6588 t = btf_type_by_id(btf, id);
6589 do {
6590 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag, field_name);
6591
6592 switch (err) {
6593 case WALK_PTR:
6594 /* For local types, the destination register cannot
6595 * become a pointer again.
6596 */
6597 if (type_is_alloc(reg->type))
6598 return SCALAR_VALUE;
6599 /* If we found the pointer or scalar on t+off,
6600 * we're done.
6601 */
6602 *next_btf_id = id;
6603 *flag = tmp_flag;
6604 return PTR_TO_BTF_ID;
6605 case WALK_SCALAR:
6606 return SCALAR_VALUE;
6607 case WALK_STRUCT:
6608 /* We found nested struct, so continue the search
6609 * by diving in it. At this point the offset is
6610 * aligned with the new type, so set it to 0.
6611 */
6612 t = btf_type_by_id(btf, id);
6613 off = 0;
6614 break;
6615 default:
6616 /* It's either error or unknown return value..
6617 * scream and leave.
6618 */
6619 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
6620 return -EINVAL;
6621 return err;
6622 }
6623 } while (t);
6624
6625 return -EINVAL;
6626}
6627
6628/* Check that two BTF types, each specified as an BTF object + id, are exactly
6629 * the same. Trivial ID check is not enough due to module BTFs, because we can
6630 * end up with two different module BTFs, but IDs point to the common type in
6631 * vmlinux BTF.
6632 */
6633bool btf_types_are_same(const struct btf *btf1, u32 id1,
6634 const struct btf *btf2, u32 id2)
6635{
6636 if (id1 != id2)
6637 return false;
6638 if (btf1 == btf2)
6639 return true;
6640 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
6641}
6642
6643bool btf_struct_ids_match(struct bpf_verifier_log *log,
6644 const struct btf *btf, u32 id, int off,
6645 const struct btf *need_btf, u32 need_type_id,
6646 bool strict)
6647{
6648 const struct btf_type *type;
6649 enum bpf_type_flag flag = 0;
6650 int err;
6651
6652 /* Are we already done? */
6653 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
6654 return true;
6655 /* In case of strict type match, we do not walk struct, the top level
6656 * type match must succeed. When strict is true, off should have already
6657 * been 0.
6658 */
6659 if (strict)
6660 return false;
6661again:
6662 type = btf_type_by_id(btf, id);
6663 if (!type)
6664 return false;
6665 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag, NULL);
6666 if (err != WALK_STRUCT)
6667 return false;
6668
6669 /* We found nested struct object. If it matches
6670 * the requested ID, we're done. Otherwise let's
6671 * continue the search with offset 0 in the new
6672 * type.
6673 */
6674 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
6675 off = 0;
6676 goto again;
6677 }
6678
6679 return true;
6680}
6681
6682static int __get_type_size(struct btf *btf, u32 btf_id,
6683 const struct btf_type **ret_type)
6684{
6685 const struct btf_type *t;
6686
6687 *ret_type = btf_type_by_id(btf, 0);
6688 if (!btf_id)
6689 /* void */
6690 return 0;
6691 t = btf_type_by_id(btf, btf_id);
6692 while (t && btf_type_is_modifier(t))
6693 t = btf_type_by_id(btf, t->type);
6694 if (!t)
6695 return -EINVAL;
6696 *ret_type = t;
6697 if (btf_type_is_ptr(t))
6698 /* kernel size of pointer. Not BPF's size of pointer*/
6699 return sizeof(void *);
6700 if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6701 return t->size;
6702 return -EINVAL;
6703}
6704
6705static u8 __get_type_fmodel_flags(const struct btf_type *t)
6706{
6707 u8 flags = 0;
6708
6709 if (__btf_type_is_struct(t))
6710 flags |= BTF_FMODEL_STRUCT_ARG;
6711 if (btf_type_is_signed_int(t))
6712 flags |= BTF_FMODEL_SIGNED_ARG;
6713
6714 return flags;
6715}
6716
6717int btf_distill_func_proto(struct bpf_verifier_log *log,
6718 struct btf *btf,
6719 const struct btf_type *func,
6720 const char *tname,
6721 struct btf_func_model *m)
6722{
6723 const struct btf_param *args;
6724 const struct btf_type *t;
6725 u32 i, nargs;
6726 int ret;
6727
6728 if (!func) {
6729 /* BTF function prototype doesn't match the verifier types.
6730 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
6731 */
6732 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
6733 m->arg_size[i] = 8;
6734 m->arg_flags[i] = 0;
6735 }
6736 m->ret_size = 8;
6737 m->ret_flags = 0;
6738 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
6739 return 0;
6740 }
6741 args = (const struct btf_param *)(func + 1);
6742 nargs = btf_type_vlen(func);
6743 if (nargs > MAX_BPF_FUNC_ARGS) {
6744 bpf_log(log,
6745 "The function %s has %d arguments. Too many.\n",
6746 tname, nargs);
6747 return -EINVAL;
6748 }
6749 ret = __get_type_size(btf, func->type, &t);
6750 if (ret < 0 || __btf_type_is_struct(t)) {
6751 bpf_log(log,
6752 "The function %s return type %s is unsupported.\n",
6753 tname, btf_type_str(t));
6754 return -EINVAL;
6755 }
6756 m->ret_size = ret;
6757 m->ret_flags = __get_type_fmodel_flags(t);
6758
6759 for (i = 0; i < nargs; i++) {
6760 if (i == nargs - 1 && args[i].type == 0) {
6761 bpf_log(log,
6762 "The function %s with variable args is unsupported.\n",
6763 tname);
6764 return -EINVAL;
6765 }
6766 ret = __get_type_size(btf, args[i].type, &t);
6767
6768 /* No support of struct argument size greater than 16 bytes */
6769 if (ret < 0 || ret > 16) {
6770 bpf_log(log,
6771 "The function %s arg%d type %s is unsupported.\n",
6772 tname, i, btf_type_str(t));
6773 return -EINVAL;
6774 }
6775 if (ret == 0) {
6776 bpf_log(log,
6777 "The function %s has malformed void argument.\n",
6778 tname);
6779 return -EINVAL;
6780 }
6781 m->arg_size[i] = ret;
6782 m->arg_flags[i] = __get_type_fmodel_flags(t);
6783 }
6784 m->nr_args = nargs;
6785 return 0;
6786}
6787
6788/* Compare BTFs of two functions assuming only scalars and pointers to context.
6789 * t1 points to BTF_KIND_FUNC in btf1
6790 * t2 points to BTF_KIND_FUNC in btf2
6791 * Returns:
6792 * EINVAL - function prototype mismatch
6793 * EFAULT - verifier bug
6794 * 0 - 99% match. The last 1% is validated by the verifier.
6795 */
6796static int btf_check_func_type_match(struct bpf_verifier_log *log,
6797 struct btf *btf1, const struct btf_type *t1,
6798 struct btf *btf2, const struct btf_type *t2)
6799{
6800 const struct btf_param *args1, *args2;
6801 const char *fn1, *fn2, *s1, *s2;
6802 u32 nargs1, nargs2, i;
6803
6804 fn1 = btf_name_by_offset(btf1, t1->name_off);
6805 fn2 = btf_name_by_offset(btf2, t2->name_off);
6806
6807 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
6808 bpf_log(log, "%s() is not a global function\n", fn1);
6809 return -EINVAL;
6810 }
6811 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
6812 bpf_log(log, "%s() is not a global function\n", fn2);
6813 return -EINVAL;
6814 }
6815
6816 t1 = btf_type_by_id(btf1, t1->type);
6817 if (!t1 || !btf_type_is_func_proto(t1))
6818 return -EFAULT;
6819 t2 = btf_type_by_id(btf2, t2->type);
6820 if (!t2 || !btf_type_is_func_proto(t2))
6821 return -EFAULT;
6822
6823 args1 = (const struct btf_param *)(t1 + 1);
6824 nargs1 = btf_type_vlen(t1);
6825 args2 = (const struct btf_param *)(t2 + 1);
6826 nargs2 = btf_type_vlen(t2);
6827
6828 if (nargs1 != nargs2) {
6829 bpf_log(log, "%s() has %d args while %s() has %d args\n",
6830 fn1, nargs1, fn2, nargs2);
6831 return -EINVAL;
6832 }
6833
6834 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6835 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6836 if (t1->info != t2->info) {
6837 bpf_log(log,
6838 "Return type %s of %s() doesn't match type %s of %s()\n",
6839 btf_type_str(t1), fn1,
6840 btf_type_str(t2), fn2);
6841 return -EINVAL;
6842 }
6843
6844 for (i = 0; i < nargs1; i++) {
6845 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
6846 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
6847
6848 if (t1->info != t2->info) {
6849 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
6850 i, fn1, btf_type_str(t1),
6851 fn2, btf_type_str(t2));
6852 return -EINVAL;
6853 }
6854 if (btf_type_has_size(t1) && t1->size != t2->size) {
6855 bpf_log(log,
6856 "arg%d in %s() has size %d while %s() has %d\n",
6857 i, fn1, t1->size,
6858 fn2, t2->size);
6859 return -EINVAL;
6860 }
6861
6862 /* global functions are validated with scalars and pointers
6863 * to context only. And only global functions can be replaced.
6864 * Hence type check only those types.
6865 */
6866 if (btf_type_is_int(t1) || btf_is_any_enum(t1))
6867 continue;
6868 if (!btf_type_is_ptr(t1)) {
6869 bpf_log(log,
6870 "arg%d in %s() has unrecognized type\n",
6871 i, fn1);
6872 return -EINVAL;
6873 }
6874 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6875 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6876 if (!btf_type_is_struct(t1)) {
6877 bpf_log(log,
6878 "arg%d in %s() is not a pointer to context\n",
6879 i, fn1);
6880 return -EINVAL;
6881 }
6882 if (!btf_type_is_struct(t2)) {
6883 bpf_log(log,
6884 "arg%d in %s() is not a pointer to context\n",
6885 i, fn2);
6886 return -EINVAL;
6887 }
6888 /* This is an optional check to make program writing easier.
6889 * Compare names of structs and report an error to the user.
6890 * btf_prepare_func_args() already checked that t2 struct
6891 * is a context type. btf_prepare_func_args() will check
6892 * later that t1 struct is a context type as well.
6893 */
6894 s1 = btf_name_by_offset(btf1, t1->name_off);
6895 s2 = btf_name_by_offset(btf2, t2->name_off);
6896 if (strcmp(s1, s2)) {
6897 bpf_log(log,
6898 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
6899 i, fn1, s1, fn2, s2);
6900 return -EINVAL;
6901 }
6902 }
6903 return 0;
6904}
6905
6906/* Compare BTFs of given program with BTF of target program */
6907int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
6908 struct btf *btf2, const struct btf_type *t2)
6909{
6910 struct btf *btf1 = prog->aux->btf;
6911 const struct btf_type *t1;
6912 u32 btf_id = 0;
6913
6914 if (!prog->aux->func_info) {
6915 bpf_log(log, "Program extension requires BTF\n");
6916 return -EINVAL;
6917 }
6918
6919 btf_id = prog->aux->func_info[0].type_id;
6920 if (!btf_id)
6921 return -EFAULT;
6922
6923 t1 = btf_type_by_id(btf1, btf_id);
6924 if (!t1 || !btf_type_is_func(t1))
6925 return -EFAULT;
6926
6927 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
6928}
6929
6930static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t)
6931{
6932 const char *name;
6933
6934 t = btf_type_by_id(btf, t->type); /* skip PTR */
6935
6936 while (btf_type_is_modifier(t))
6937 t = btf_type_by_id(btf, t->type);
6938
6939 /* allow either struct or struct forward declaration */
6940 if (btf_type_is_struct(t) ||
6941 (btf_type_is_fwd(t) && btf_type_kflag(t) == 0)) {
6942 name = btf_str_by_offset(btf, t->name_off);
6943 return name && strcmp(name, "bpf_dynptr") == 0;
6944 }
6945
6946 return false;
6947}
6948
6949/* Process BTF of a function to produce high-level expectation of function
6950 * arguments (like ARG_PTR_TO_CTX, or ARG_PTR_TO_MEM, etc). This information
6951 * is cached in subprog info for reuse.
6952 * Returns:
6953 * EFAULT - there is a verifier bug. Abort verification.
6954 * EINVAL - cannot convert BTF.
6955 * 0 - Successfully processed BTF and constructed argument expectations.
6956 */
6957int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
6958{
6959 bool is_global = subprog_aux(env, subprog)->linkage == BTF_FUNC_GLOBAL;
6960 struct bpf_subprog_info *sub = subprog_info(env, subprog);
6961 struct bpf_verifier_log *log = &env->log;
6962 struct bpf_prog *prog = env->prog;
6963 enum bpf_prog_type prog_type = prog->type;
6964 struct btf *btf = prog->aux->btf;
6965 const struct btf_param *args;
6966 const struct btf_type *t, *ref_t, *fn_t;
6967 u32 i, nargs, btf_id;
6968 const char *tname;
6969
6970 if (sub->args_cached)
6971 return 0;
6972
6973 if (!prog->aux->func_info) {
6974 bpf_log(log, "Verifier bug\n");
6975 return -EFAULT;
6976 }
6977
6978 btf_id = prog->aux->func_info[subprog].type_id;
6979 if (!btf_id) {
6980 if (!is_global) /* not fatal for static funcs */
6981 return -EINVAL;
6982 bpf_log(log, "Global functions need valid BTF\n");
6983 return -EFAULT;
6984 }
6985
6986 fn_t = btf_type_by_id(btf, btf_id);
6987 if (!fn_t || !btf_type_is_func(fn_t)) {
6988 /* These checks were already done by the verifier while loading
6989 * struct bpf_func_info
6990 */
6991 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
6992 subprog);
6993 return -EFAULT;
6994 }
6995 tname = btf_name_by_offset(btf, fn_t->name_off);
6996
6997 if (prog->aux->func_info_aux[subprog].unreliable) {
6998 bpf_log(log, "Verifier bug in function %s()\n", tname);
6999 return -EFAULT;
7000 }
7001 if (prog_type == BPF_PROG_TYPE_EXT)
7002 prog_type = prog->aux->dst_prog->type;
7003
7004 t = btf_type_by_id(btf, fn_t->type);
7005 if (!t || !btf_type_is_func_proto(t)) {
7006 bpf_log(log, "Invalid type of function %s()\n", tname);
7007 return -EFAULT;
7008 }
7009 args = (const struct btf_param *)(t + 1);
7010 nargs = btf_type_vlen(t);
7011 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
7012 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
7013 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
7014 return -EINVAL;
7015 }
7016 /* check that function returns int, exception cb also requires this */
7017 t = btf_type_by_id(btf, t->type);
7018 while (btf_type_is_modifier(t))
7019 t = btf_type_by_id(btf, t->type);
7020 if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
7021 bpf_log(log,
7022 "Global function %s() doesn't return scalar. Only those are supported.\n",
7023 tname);
7024 return -EINVAL;
7025 }
7026 /* Convert BTF function arguments into verifier types.
7027 * Only PTR_TO_CTX and SCALAR are supported atm.
7028 */
7029 for (i = 0; i < nargs; i++) {
7030 bool is_nonnull = false;
7031 const char *tag;
7032
7033 t = btf_type_by_id(btf, args[i].type);
7034
7035 tag = btf_find_decl_tag_value(btf, fn_t, i, "arg:");
7036 if (IS_ERR(tag) && PTR_ERR(tag) == -ENOENT) {
7037 tag = NULL;
7038 } else if (IS_ERR(tag)) {
7039 bpf_log(log, "arg#%d type's tag fetching failure: %ld\n", i, PTR_ERR(tag));
7040 return PTR_ERR(tag);
7041 }
7042 /* 'arg:<tag>' decl_tag takes precedence over derivation of
7043 * register type from BTF type itself
7044 */
7045 if (tag) {
7046 /* disallow arg tags in static subprogs */
7047 if (!is_global) {
7048 bpf_log(log, "arg#%d type tag is not supported in static functions\n", i);
7049 return -EOPNOTSUPP;
7050 }
7051 if (strcmp(tag, "ctx") == 0) {
7052 sub->args[i].arg_type = ARG_PTR_TO_CTX;
7053 continue;
7054 }
7055 if (strcmp(tag, "nonnull") == 0)
7056 is_nonnull = true;
7057 }
7058
7059 while (btf_type_is_modifier(t))
7060 t = btf_type_by_id(btf, t->type);
7061 if (btf_type_is_int(t) || btf_is_any_enum(t)) {
7062 sub->args[i].arg_type = ARG_ANYTHING;
7063 continue;
7064 }
7065 if (btf_type_is_ptr(t) && btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
7066 sub->args[i].arg_type = ARG_PTR_TO_CTX;
7067 continue;
7068 }
7069 if (btf_type_is_ptr(t) && btf_is_dynptr_ptr(btf, t)) {
7070 sub->args[i].arg_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY;
7071 continue;
7072 }
7073 if (is_global && btf_type_is_ptr(t)) {
7074 u32 mem_size;
7075
7076 t = btf_type_skip_modifiers(btf, t->type, NULL);
7077 ref_t = btf_resolve_size(btf, t, &mem_size);
7078 if (IS_ERR(ref_t)) {
7079 bpf_log(log,
7080 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
7081 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
7082 PTR_ERR(ref_t));
7083 return -EINVAL;
7084 }
7085
7086 sub->args[i].arg_type = is_nonnull ? ARG_PTR_TO_MEM : ARG_PTR_TO_MEM_OR_NULL;
7087 sub->args[i].mem_size = mem_size;
7088 continue;
7089 }
7090 if (is_nonnull) {
7091 bpf_log(log, "arg#%d marked as non-null, but is not a pointer type\n", i);
7092 return -EINVAL;
7093 }
7094 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
7095 i, btf_type_str(t), tname);
7096 return -EINVAL;
7097 }
7098
7099 for (i = 0; i < nargs; i++) {
7100 const char *tag;
7101
7102 if (sub->args[i].arg_type != ARG_PTR_TO_CTX)
7103 continue;
7104
7105 /* check if arg has "arg:ctx" tag */
7106 t = btf_type_by_id(btf, args[i].type);
7107 tag = btf_find_decl_tag_value(btf, fn_t, i, "arg:");
7108 if (IS_ERR_OR_NULL(tag) || strcmp(tag, "ctx") != 0)
7109 continue;
7110
7111 if (btf_validate_prog_ctx_type(log, btf, t, i, prog_type,
7112 prog->expected_attach_type))
7113 return -EINVAL;
7114 }
7115
7116 sub->arg_cnt = nargs;
7117 sub->args_cached = true;
7118
7119 return 0;
7120}
7121
7122static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
7123 struct btf_show *show)
7124{
7125 const struct btf_type *t = btf_type_by_id(btf, type_id);
7126
7127 show->btf = btf;
7128 memset(&show->state, 0, sizeof(show->state));
7129 memset(&show->obj, 0, sizeof(show->obj));
7130
7131 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
7132}
7133
7134static void btf_seq_show(struct btf_show *show, const char *fmt,
7135 va_list args)
7136{
7137 seq_vprintf((struct seq_file *)show->target, fmt, args);
7138}
7139
7140int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
7141 void *obj, struct seq_file *m, u64 flags)
7142{
7143 struct btf_show sseq;
7144
7145 sseq.target = m;
7146 sseq.showfn = btf_seq_show;
7147 sseq.flags = flags;
7148
7149 btf_type_show(btf, type_id, obj, &sseq);
7150
7151 return sseq.state.status;
7152}
7153
7154void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
7155 struct seq_file *m)
7156{
7157 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
7158 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
7159 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
7160}
7161
7162struct btf_show_snprintf {
7163 struct btf_show show;
7164 int len_left; /* space left in string */
7165 int len; /* length we would have written */
7166};
7167
7168static void btf_snprintf_show(struct btf_show *show, const char *fmt,
7169 va_list args)
7170{
7171 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
7172 int len;
7173
7174 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
7175
7176 if (len < 0) {
7177 ssnprintf->len_left = 0;
7178 ssnprintf->len = len;
7179 } else if (len >= ssnprintf->len_left) {
7180 /* no space, drive on to get length we would have written */
7181 ssnprintf->len_left = 0;
7182 ssnprintf->len += len;
7183 } else {
7184 ssnprintf->len_left -= len;
7185 ssnprintf->len += len;
7186 show->target += len;
7187 }
7188}
7189
7190int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
7191 char *buf, int len, u64 flags)
7192{
7193 struct btf_show_snprintf ssnprintf;
7194
7195 ssnprintf.show.target = buf;
7196 ssnprintf.show.flags = flags;
7197 ssnprintf.show.showfn = btf_snprintf_show;
7198 ssnprintf.len_left = len;
7199 ssnprintf.len = 0;
7200
7201 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
7202
7203 /* If we encountered an error, return it. */
7204 if (ssnprintf.show.state.status)
7205 return ssnprintf.show.state.status;
7206
7207 /* Otherwise return length we would have written */
7208 return ssnprintf.len;
7209}
7210
7211#ifdef CONFIG_PROC_FS
7212static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
7213{
7214 const struct btf *btf = filp->private_data;
7215
7216 seq_printf(m, "btf_id:\t%u\n", btf->id);
7217}
7218#endif
7219
7220static int btf_release(struct inode *inode, struct file *filp)
7221{
7222 btf_put(filp->private_data);
7223 return 0;
7224}
7225
7226const struct file_operations btf_fops = {
7227#ifdef CONFIG_PROC_FS
7228 .show_fdinfo = bpf_btf_show_fdinfo,
7229#endif
7230 .release = btf_release,
7231};
7232
7233static int __btf_new_fd(struct btf *btf)
7234{
7235 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
7236}
7237
7238int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
7239{
7240 struct btf *btf;
7241 int ret;
7242
7243 btf = btf_parse(attr, uattr, uattr_size);
7244 if (IS_ERR(btf))
7245 return PTR_ERR(btf);
7246
7247 ret = btf_alloc_id(btf);
7248 if (ret) {
7249 btf_free(btf);
7250 return ret;
7251 }
7252
7253 /*
7254 * The BTF ID is published to the userspace.
7255 * All BTF free must go through call_rcu() from
7256 * now on (i.e. free by calling btf_put()).
7257 */
7258
7259 ret = __btf_new_fd(btf);
7260 if (ret < 0)
7261 btf_put(btf);
7262
7263 return ret;
7264}
7265
7266struct btf *btf_get_by_fd(int fd)
7267{
7268 struct btf *btf;
7269 struct fd f;
7270
7271 f = fdget(fd);
7272
7273 if (!f.file)
7274 return ERR_PTR(-EBADF);
7275
7276 if (f.file->f_op != &btf_fops) {
7277 fdput(f);
7278 return ERR_PTR(-EINVAL);
7279 }
7280
7281 btf = f.file->private_data;
7282 refcount_inc(&btf->refcnt);
7283 fdput(f);
7284
7285 return btf;
7286}
7287
7288int btf_get_info_by_fd(const struct btf *btf,
7289 const union bpf_attr *attr,
7290 union bpf_attr __user *uattr)
7291{
7292 struct bpf_btf_info __user *uinfo;
7293 struct bpf_btf_info info;
7294 u32 info_copy, btf_copy;
7295 void __user *ubtf;
7296 char __user *uname;
7297 u32 uinfo_len, uname_len, name_len;
7298 int ret = 0;
7299
7300 uinfo = u64_to_user_ptr(attr->info.info);
7301 uinfo_len = attr->info.info_len;
7302
7303 info_copy = min_t(u32, uinfo_len, sizeof(info));
7304 memset(&info, 0, sizeof(info));
7305 if (copy_from_user(&info, uinfo, info_copy))
7306 return -EFAULT;
7307
7308 info.id = btf->id;
7309 ubtf = u64_to_user_ptr(info.btf);
7310 btf_copy = min_t(u32, btf->data_size, info.btf_size);
7311 if (copy_to_user(ubtf, btf->data, btf_copy))
7312 return -EFAULT;
7313 info.btf_size = btf->data_size;
7314
7315 info.kernel_btf = btf->kernel_btf;
7316
7317 uname = u64_to_user_ptr(info.name);
7318 uname_len = info.name_len;
7319 if (!uname ^ !uname_len)
7320 return -EINVAL;
7321
7322 name_len = strlen(btf->name);
7323 info.name_len = name_len;
7324
7325 if (uname) {
7326 if (uname_len >= name_len + 1) {
7327 if (copy_to_user(uname, btf->name, name_len + 1))
7328 return -EFAULT;
7329 } else {
7330 char zero = '\0';
7331
7332 if (copy_to_user(uname, btf->name, uname_len - 1))
7333 return -EFAULT;
7334 if (put_user(zero, uname + uname_len - 1))
7335 return -EFAULT;
7336 /* let user-space know about too short buffer */
7337 ret = -ENOSPC;
7338 }
7339 }
7340
7341 if (copy_to_user(uinfo, &info, info_copy) ||
7342 put_user(info_copy, &uattr->info.info_len))
7343 return -EFAULT;
7344
7345 return ret;
7346}
7347
7348int btf_get_fd_by_id(u32 id)
7349{
7350 struct btf *btf;
7351 int fd;
7352
7353 rcu_read_lock();
7354 btf = idr_find(&btf_idr, id);
7355 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
7356 btf = ERR_PTR(-ENOENT);
7357 rcu_read_unlock();
7358
7359 if (IS_ERR(btf))
7360 return PTR_ERR(btf);
7361
7362 fd = __btf_new_fd(btf);
7363 if (fd < 0)
7364 btf_put(btf);
7365
7366 return fd;
7367}
7368
7369u32 btf_obj_id(const struct btf *btf)
7370{
7371 return btf->id;
7372}
7373
7374bool btf_is_kernel(const struct btf *btf)
7375{
7376 return btf->kernel_btf;
7377}
7378
7379bool btf_is_module(const struct btf *btf)
7380{
7381 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
7382}
7383
7384enum {
7385 BTF_MODULE_F_LIVE = (1 << 0),
7386};
7387
7388#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7389struct btf_module {
7390 struct list_head list;
7391 struct module *module;
7392 struct btf *btf;
7393 struct bin_attribute *sysfs_attr;
7394 int flags;
7395};
7396
7397static LIST_HEAD(btf_modules);
7398static DEFINE_MUTEX(btf_module_mutex);
7399
7400static ssize_t
7401btf_module_read(struct file *file, struct kobject *kobj,
7402 struct bin_attribute *bin_attr,
7403 char *buf, loff_t off, size_t len)
7404{
7405 const struct btf *btf = bin_attr->private;
7406
7407 memcpy(buf, btf->data + off, len);
7408 return len;
7409}
7410
7411static void purge_cand_cache(struct btf *btf);
7412
7413static int btf_module_notify(struct notifier_block *nb, unsigned long op,
7414 void *module)
7415{
7416 struct btf_module *btf_mod, *tmp;
7417 struct module *mod = module;
7418 struct btf *btf;
7419 int err = 0;
7420
7421 if (mod->btf_data_size == 0 ||
7422 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
7423 op != MODULE_STATE_GOING))
7424 goto out;
7425
7426 switch (op) {
7427 case MODULE_STATE_COMING:
7428 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
7429 if (!btf_mod) {
7430 err = -ENOMEM;
7431 goto out;
7432 }
7433 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
7434 if (IS_ERR(btf)) {
7435 kfree(btf_mod);
7436 if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH)) {
7437 pr_warn("failed to validate module [%s] BTF: %ld\n",
7438 mod->name, PTR_ERR(btf));
7439 err = PTR_ERR(btf);
7440 } else {
7441 pr_warn_once("Kernel module BTF mismatch detected, BTF debug info may be unavailable for some modules\n");
7442 }
7443 goto out;
7444 }
7445 err = btf_alloc_id(btf);
7446 if (err) {
7447 btf_free(btf);
7448 kfree(btf_mod);
7449 goto out;
7450 }
7451
7452 purge_cand_cache(NULL);
7453 mutex_lock(&btf_module_mutex);
7454 btf_mod->module = module;
7455 btf_mod->btf = btf;
7456 list_add(&btf_mod->list, &btf_modules);
7457 mutex_unlock(&btf_module_mutex);
7458
7459 if (IS_ENABLED(CONFIG_SYSFS)) {
7460 struct bin_attribute *attr;
7461
7462 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
7463 if (!attr)
7464 goto out;
7465
7466 sysfs_bin_attr_init(attr);
7467 attr->attr.name = btf->name;
7468 attr->attr.mode = 0444;
7469 attr->size = btf->data_size;
7470 attr->private = btf;
7471 attr->read = btf_module_read;
7472
7473 err = sysfs_create_bin_file(btf_kobj, attr);
7474 if (err) {
7475 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
7476 mod->name, err);
7477 kfree(attr);
7478 err = 0;
7479 goto out;
7480 }
7481
7482 btf_mod->sysfs_attr = attr;
7483 }
7484
7485 break;
7486 case MODULE_STATE_LIVE:
7487 mutex_lock(&btf_module_mutex);
7488 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7489 if (btf_mod->module != module)
7490 continue;
7491
7492 btf_mod->flags |= BTF_MODULE_F_LIVE;
7493 break;
7494 }
7495 mutex_unlock(&btf_module_mutex);
7496 break;
7497 case MODULE_STATE_GOING:
7498 mutex_lock(&btf_module_mutex);
7499 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7500 if (btf_mod->module != module)
7501 continue;
7502
7503 list_del(&btf_mod->list);
7504 if (btf_mod->sysfs_attr)
7505 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
7506 purge_cand_cache(btf_mod->btf);
7507 btf_put(btf_mod->btf);
7508 kfree(btf_mod->sysfs_attr);
7509 kfree(btf_mod);
7510 break;
7511 }
7512 mutex_unlock(&btf_module_mutex);
7513 break;
7514 }
7515out:
7516 return notifier_from_errno(err);
7517}
7518
7519static struct notifier_block btf_module_nb = {
7520 .notifier_call = btf_module_notify,
7521};
7522
7523static int __init btf_module_init(void)
7524{
7525 register_module_notifier(&btf_module_nb);
7526 return 0;
7527}
7528
7529fs_initcall(btf_module_init);
7530#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
7531
7532struct module *btf_try_get_module(const struct btf *btf)
7533{
7534 struct module *res = NULL;
7535#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7536 struct btf_module *btf_mod, *tmp;
7537
7538 mutex_lock(&btf_module_mutex);
7539 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7540 if (btf_mod->btf != btf)
7541 continue;
7542
7543 /* We must only consider module whose __init routine has
7544 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
7545 * which is set from the notifier callback for
7546 * MODULE_STATE_LIVE.
7547 */
7548 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
7549 res = btf_mod->module;
7550
7551 break;
7552 }
7553 mutex_unlock(&btf_module_mutex);
7554#endif
7555
7556 return res;
7557}
7558
7559/* Returns struct btf corresponding to the struct module.
7560 * This function can return NULL or ERR_PTR.
7561 */
7562static struct btf *btf_get_module_btf(const struct module *module)
7563{
7564#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7565 struct btf_module *btf_mod, *tmp;
7566#endif
7567 struct btf *btf = NULL;
7568
7569 if (!module) {
7570 btf = bpf_get_btf_vmlinux();
7571 if (!IS_ERR_OR_NULL(btf))
7572 btf_get(btf);
7573 return btf;
7574 }
7575
7576#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7577 mutex_lock(&btf_module_mutex);
7578 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7579 if (btf_mod->module != module)
7580 continue;
7581
7582 btf_get(btf_mod->btf);
7583 btf = btf_mod->btf;
7584 break;
7585 }
7586 mutex_unlock(&btf_module_mutex);
7587#endif
7588
7589 return btf;
7590}
7591
7592BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
7593{
7594 struct btf *btf = NULL;
7595 int btf_obj_fd = 0;
7596 long ret;
7597
7598 if (flags)
7599 return -EINVAL;
7600
7601 if (name_sz <= 1 || name[name_sz - 1])
7602 return -EINVAL;
7603
7604 ret = bpf_find_btf_id(name, kind, &btf);
7605 if (ret > 0 && btf_is_module(btf)) {
7606 btf_obj_fd = __btf_new_fd(btf);
7607 if (btf_obj_fd < 0) {
7608 btf_put(btf);
7609 return btf_obj_fd;
7610 }
7611 return ret | (((u64)btf_obj_fd) << 32);
7612 }
7613 if (ret > 0)
7614 btf_put(btf);
7615 return ret;
7616}
7617
7618const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
7619 .func = bpf_btf_find_by_name_kind,
7620 .gpl_only = false,
7621 .ret_type = RET_INTEGER,
7622 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
7623 .arg2_type = ARG_CONST_SIZE,
7624 .arg3_type = ARG_ANYTHING,
7625 .arg4_type = ARG_ANYTHING,
7626};
7627
7628BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
7629#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
7630BTF_TRACING_TYPE_xxx
7631#undef BTF_TRACING_TYPE
7632
7633static int btf_check_iter_kfuncs(struct btf *btf, const char *func_name,
7634 const struct btf_type *func, u32 func_flags)
7635{
7636 u32 flags = func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
7637 const char *name, *sfx, *iter_name;
7638 const struct btf_param *arg;
7639 const struct btf_type *t;
7640 char exp_name[128];
7641 u32 nr_args;
7642
7643 /* exactly one of KF_ITER_{NEW,NEXT,DESTROY} can be set */
7644 if (!flags || (flags & (flags - 1)))
7645 return -EINVAL;
7646
7647 /* any BPF iter kfunc should have `struct bpf_iter_<type> *` first arg */
7648 nr_args = btf_type_vlen(func);
7649 if (nr_args < 1)
7650 return -EINVAL;
7651
7652 arg = &btf_params(func)[0];
7653 t = btf_type_skip_modifiers(btf, arg->type, NULL);
7654 if (!t || !btf_type_is_ptr(t))
7655 return -EINVAL;
7656 t = btf_type_skip_modifiers(btf, t->type, NULL);
7657 if (!t || !__btf_type_is_struct(t))
7658 return -EINVAL;
7659
7660 name = btf_name_by_offset(btf, t->name_off);
7661 if (!name || strncmp(name, ITER_PREFIX, sizeof(ITER_PREFIX) - 1))
7662 return -EINVAL;
7663
7664 /* sizeof(struct bpf_iter_<type>) should be a multiple of 8 to
7665 * fit nicely in stack slots
7666 */
7667 if (t->size == 0 || (t->size % 8))
7668 return -EINVAL;
7669
7670 /* validate bpf_iter_<type>_{new,next,destroy}(struct bpf_iter_<type> *)
7671 * naming pattern
7672 */
7673 iter_name = name + sizeof(ITER_PREFIX) - 1;
7674 if (flags & KF_ITER_NEW)
7675 sfx = "new";
7676 else if (flags & KF_ITER_NEXT)
7677 sfx = "next";
7678 else /* (flags & KF_ITER_DESTROY) */
7679 sfx = "destroy";
7680
7681 snprintf(exp_name, sizeof(exp_name), "bpf_iter_%s_%s", iter_name, sfx);
7682 if (strcmp(func_name, exp_name))
7683 return -EINVAL;
7684
7685 /* only iter constructor should have extra arguments */
7686 if (!(flags & KF_ITER_NEW) && nr_args != 1)
7687 return -EINVAL;
7688
7689 if (flags & KF_ITER_NEXT) {
7690 /* bpf_iter_<type>_next() should return pointer */
7691 t = btf_type_skip_modifiers(btf, func->type, NULL);
7692 if (!t || !btf_type_is_ptr(t))
7693 return -EINVAL;
7694 }
7695
7696 if (flags & KF_ITER_DESTROY) {
7697 /* bpf_iter_<type>_destroy() should return void */
7698 t = btf_type_by_id(btf, func->type);
7699 if (!t || !btf_type_is_void(t))
7700 return -EINVAL;
7701 }
7702
7703 return 0;
7704}
7705
7706static int btf_check_kfunc_protos(struct btf *btf, u32 func_id, u32 func_flags)
7707{
7708 const struct btf_type *func;
7709 const char *func_name;
7710 int err;
7711
7712 /* any kfunc should be FUNC -> FUNC_PROTO */
7713 func = btf_type_by_id(btf, func_id);
7714 if (!func || !btf_type_is_func(func))
7715 return -EINVAL;
7716
7717 /* sanity check kfunc name */
7718 func_name = btf_name_by_offset(btf, func->name_off);
7719 if (!func_name || !func_name[0])
7720 return -EINVAL;
7721
7722 func = btf_type_by_id(btf, func->type);
7723 if (!func || !btf_type_is_func_proto(func))
7724 return -EINVAL;
7725
7726 if (func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY)) {
7727 err = btf_check_iter_kfuncs(btf, func_name, func, func_flags);
7728 if (err)
7729 return err;
7730 }
7731
7732 return 0;
7733}
7734
7735/* Kernel Function (kfunc) BTF ID set registration API */
7736
7737static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
7738 const struct btf_kfunc_id_set *kset)
7739{
7740 struct btf_kfunc_hook_filter *hook_filter;
7741 struct btf_id_set8 *add_set = kset->set;
7742 bool vmlinux_set = !btf_is_module(btf);
7743 bool add_filter = !!kset->filter;
7744 struct btf_kfunc_set_tab *tab;
7745 struct btf_id_set8 *set;
7746 u32 set_cnt;
7747 int ret;
7748
7749 if (hook >= BTF_KFUNC_HOOK_MAX) {
7750 ret = -EINVAL;
7751 goto end;
7752 }
7753
7754 if (!add_set->cnt)
7755 return 0;
7756
7757 tab = btf->kfunc_set_tab;
7758
7759 if (tab && add_filter) {
7760 u32 i;
7761
7762 hook_filter = &tab->hook_filters[hook];
7763 for (i = 0; i < hook_filter->nr_filters; i++) {
7764 if (hook_filter->filters[i] == kset->filter) {
7765 add_filter = false;
7766 break;
7767 }
7768 }
7769
7770 if (add_filter && hook_filter->nr_filters == BTF_KFUNC_FILTER_MAX_CNT) {
7771 ret = -E2BIG;
7772 goto end;
7773 }
7774 }
7775
7776 if (!tab) {
7777 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
7778 if (!tab)
7779 return -ENOMEM;
7780 btf->kfunc_set_tab = tab;
7781 }
7782
7783 set = tab->sets[hook];
7784 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
7785 * for module sets.
7786 */
7787 if (WARN_ON_ONCE(set && !vmlinux_set)) {
7788 ret = -EINVAL;
7789 goto end;
7790 }
7791
7792 /* We don't need to allocate, concatenate, and sort module sets, because
7793 * only one is allowed per hook. Hence, we can directly assign the
7794 * pointer and return.
7795 */
7796 if (!vmlinux_set) {
7797 tab->sets[hook] = add_set;
7798 goto do_add_filter;
7799 }
7800
7801 /* In case of vmlinux sets, there may be more than one set being
7802 * registered per hook. To create a unified set, we allocate a new set
7803 * and concatenate all individual sets being registered. While each set
7804 * is individually sorted, they may become unsorted when concatenated,
7805 * hence re-sorting the final set again is required to make binary
7806 * searching the set using btf_id_set8_contains function work.
7807 */
7808 set_cnt = set ? set->cnt : 0;
7809
7810 if (set_cnt > U32_MAX - add_set->cnt) {
7811 ret = -EOVERFLOW;
7812 goto end;
7813 }
7814
7815 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
7816 ret = -E2BIG;
7817 goto end;
7818 }
7819
7820 /* Grow set */
7821 set = krealloc(tab->sets[hook],
7822 offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
7823 GFP_KERNEL | __GFP_NOWARN);
7824 if (!set) {
7825 ret = -ENOMEM;
7826 goto end;
7827 }
7828
7829 /* For newly allocated set, initialize set->cnt to 0 */
7830 if (!tab->sets[hook])
7831 set->cnt = 0;
7832 tab->sets[hook] = set;
7833
7834 /* Concatenate the two sets */
7835 memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
7836 set->cnt += add_set->cnt;
7837
7838 sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
7839
7840do_add_filter:
7841 if (add_filter) {
7842 hook_filter = &tab->hook_filters[hook];
7843 hook_filter->filters[hook_filter->nr_filters++] = kset->filter;
7844 }
7845 return 0;
7846end:
7847 btf_free_kfunc_set_tab(btf);
7848 return ret;
7849}
7850
7851static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
7852 enum btf_kfunc_hook hook,
7853 u32 kfunc_btf_id,
7854 const struct bpf_prog *prog)
7855{
7856 struct btf_kfunc_hook_filter *hook_filter;
7857 struct btf_id_set8 *set;
7858 u32 *id, i;
7859
7860 if (hook >= BTF_KFUNC_HOOK_MAX)
7861 return NULL;
7862 if (!btf->kfunc_set_tab)
7863 return NULL;
7864 hook_filter = &btf->kfunc_set_tab->hook_filters[hook];
7865 for (i = 0; i < hook_filter->nr_filters; i++) {
7866 if (hook_filter->filters[i](prog, kfunc_btf_id))
7867 return NULL;
7868 }
7869 set = btf->kfunc_set_tab->sets[hook];
7870 if (!set)
7871 return NULL;
7872 id = btf_id_set8_contains(set, kfunc_btf_id);
7873 if (!id)
7874 return NULL;
7875 /* The flags for BTF ID are located next to it */
7876 return id + 1;
7877}
7878
7879static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
7880{
7881 switch (prog_type) {
7882 case BPF_PROG_TYPE_UNSPEC:
7883 return BTF_KFUNC_HOOK_COMMON;
7884 case BPF_PROG_TYPE_XDP:
7885 return BTF_KFUNC_HOOK_XDP;
7886 case BPF_PROG_TYPE_SCHED_CLS:
7887 return BTF_KFUNC_HOOK_TC;
7888 case BPF_PROG_TYPE_STRUCT_OPS:
7889 return BTF_KFUNC_HOOK_STRUCT_OPS;
7890 case BPF_PROG_TYPE_TRACING:
7891 case BPF_PROG_TYPE_LSM:
7892 return BTF_KFUNC_HOOK_TRACING;
7893 case BPF_PROG_TYPE_SYSCALL:
7894 return BTF_KFUNC_HOOK_SYSCALL;
7895 case BPF_PROG_TYPE_CGROUP_SKB:
7896 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
7897 return BTF_KFUNC_HOOK_CGROUP_SKB;
7898 case BPF_PROG_TYPE_SCHED_ACT:
7899 return BTF_KFUNC_HOOK_SCHED_ACT;
7900 case BPF_PROG_TYPE_SK_SKB:
7901 return BTF_KFUNC_HOOK_SK_SKB;
7902 case BPF_PROG_TYPE_SOCKET_FILTER:
7903 return BTF_KFUNC_HOOK_SOCKET_FILTER;
7904 case BPF_PROG_TYPE_LWT_OUT:
7905 case BPF_PROG_TYPE_LWT_IN:
7906 case BPF_PROG_TYPE_LWT_XMIT:
7907 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
7908 return BTF_KFUNC_HOOK_LWT;
7909 case BPF_PROG_TYPE_NETFILTER:
7910 return BTF_KFUNC_HOOK_NETFILTER;
7911 default:
7912 return BTF_KFUNC_HOOK_MAX;
7913 }
7914}
7915
7916/* Caution:
7917 * Reference to the module (obtained using btf_try_get_module) corresponding to
7918 * the struct btf *MUST* be held when calling this function from verifier
7919 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
7920 * keeping the reference for the duration of the call provides the necessary
7921 * protection for looking up a well-formed btf->kfunc_set_tab.
7922 */
7923u32 *btf_kfunc_id_set_contains(const struct btf *btf,
7924 u32 kfunc_btf_id,
7925 const struct bpf_prog *prog)
7926{
7927 enum bpf_prog_type prog_type = resolve_prog_type(prog);
7928 enum btf_kfunc_hook hook;
7929 u32 *kfunc_flags;
7930
7931 kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id, prog);
7932 if (kfunc_flags)
7933 return kfunc_flags;
7934
7935 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7936 return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id, prog);
7937}
7938
7939u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
7940 const struct bpf_prog *prog)
7941{
7942 return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id, prog);
7943}
7944
7945static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
7946 const struct btf_kfunc_id_set *kset)
7947{
7948 struct btf *btf;
7949 int ret, i;
7950
7951 btf = btf_get_module_btf(kset->owner);
7952 if (!btf) {
7953 if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7954 pr_err("missing vmlinux BTF, cannot register kfuncs\n");
7955 return -ENOENT;
7956 }
7957 if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
7958 pr_warn("missing module BTF, cannot register kfuncs\n");
7959 return 0;
7960 }
7961 if (IS_ERR(btf))
7962 return PTR_ERR(btf);
7963
7964 for (i = 0; i < kset->set->cnt; i++) {
7965 ret = btf_check_kfunc_protos(btf, kset->set->pairs[i].id,
7966 kset->set->pairs[i].flags);
7967 if (ret)
7968 goto err_out;
7969 }
7970
7971 ret = btf_populate_kfunc_set(btf, hook, kset);
7972
7973err_out:
7974 btf_put(btf);
7975 return ret;
7976}
7977
7978/* This function must be invoked only from initcalls/module init functions */
7979int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
7980 const struct btf_kfunc_id_set *kset)
7981{
7982 enum btf_kfunc_hook hook;
7983
7984 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7985 return __register_btf_kfunc_id_set(hook, kset);
7986}
7987EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
7988
7989/* This function must be invoked only from initcalls/module init functions */
7990int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset)
7991{
7992 return __register_btf_kfunc_id_set(BTF_KFUNC_HOOK_FMODRET, kset);
7993}
7994EXPORT_SYMBOL_GPL(register_btf_fmodret_id_set);
7995
7996s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
7997{
7998 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
7999 struct btf_id_dtor_kfunc *dtor;
8000
8001 if (!tab)
8002 return -ENOENT;
8003 /* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
8004 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
8005 */
8006 BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
8007 dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
8008 if (!dtor)
8009 return -ENOENT;
8010 return dtor->kfunc_btf_id;
8011}
8012
8013static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
8014{
8015 const struct btf_type *dtor_func, *dtor_func_proto, *t;
8016 const struct btf_param *args;
8017 s32 dtor_btf_id;
8018 u32 nr_args, i;
8019
8020 for (i = 0; i < cnt; i++) {
8021 dtor_btf_id = dtors[i].kfunc_btf_id;
8022
8023 dtor_func = btf_type_by_id(btf, dtor_btf_id);
8024 if (!dtor_func || !btf_type_is_func(dtor_func))
8025 return -EINVAL;
8026
8027 dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
8028 if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
8029 return -EINVAL;
8030
8031 /* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
8032 t = btf_type_by_id(btf, dtor_func_proto->type);
8033 if (!t || !btf_type_is_void(t))
8034 return -EINVAL;
8035
8036 nr_args = btf_type_vlen(dtor_func_proto);
8037 if (nr_args != 1)
8038 return -EINVAL;
8039 args = btf_params(dtor_func_proto);
8040 t = btf_type_by_id(btf, args[0].type);
8041 /* Allow any pointer type, as width on targets Linux supports
8042 * will be same for all pointer types (i.e. sizeof(void *))
8043 */
8044 if (!t || !btf_type_is_ptr(t))
8045 return -EINVAL;
8046 }
8047 return 0;
8048}
8049
8050/* This function must be invoked only from initcalls/module init functions */
8051int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
8052 struct module *owner)
8053{
8054 struct btf_id_dtor_kfunc_tab *tab;
8055 struct btf *btf;
8056 u32 tab_cnt;
8057 int ret;
8058
8059 btf = btf_get_module_btf(owner);
8060 if (!btf) {
8061 if (!owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
8062 pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n");
8063 return -ENOENT;
8064 }
8065 if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
8066 pr_err("missing module BTF, cannot register dtor kfuncs\n");
8067 return -ENOENT;
8068 }
8069 return 0;
8070 }
8071 if (IS_ERR(btf))
8072 return PTR_ERR(btf);
8073
8074 if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8075 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8076 ret = -E2BIG;
8077 goto end;
8078 }
8079
8080 /* Ensure that the prototype of dtor kfuncs being registered is sane */
8081 ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
8082 if (ret < 0)
8083 goto end;
8084
8085 tab = btf->dtor_kfunc_tab;
8086 /* Only one call allowed for modules */
8087 if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
8088 ret = -EINVAL;
8089 goto end;
8090 }
8091
8092 tab_cnt = tab ? tab->cnt : 0;
8093 if (tab_cnt > U32_MAX - add_cnt) {
8094 ret = -EOVERFLOW;
8095 goto end;
8096 }
8097 if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8098 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8099 ret = -E2BIG;
8100 goto end;
8101 }
8102
8103 tab = krealloc(btf->dtor_kfunc_tab,
8104 offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
8105 GFP_KERNEL | __GFP_NOWARN);
8106 if (!tab) {
8107 ret = -ENOMEM;
8108 goto end;
8109 }
8110
8111 if (!btf->dtor_kfunc_tab)
8112 tab->cnt = 0;
8113 btf->dtor_kfunc_tab = tab;
8114
8115 memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
8116 tab->cnt += add_cnt;
8117
8118 sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
8119
8120end:
8121 if (ret)
8122 btf_free_dtor_kfunc_tab(btf);
8123 btf_put(btf);
8124 return ret;
8125}
8126EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
8127
8128#define MAX_TYPES_ARE_COMPAT_DEPTH 2
8129
8130/* Check local and target types for compatibility. This check is used for
8131 * type-based CO-RE relocations and follow slightly different rules than
8132 * field-based relocations. This function assumes that root types were already
8133 * checked for name match. Beyond that initial root-level name check, names
8134 * are completely ignored. Compatibility rules are as follows:
8135 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
8136 * kind should match for local and target types (i.e., STRUCT is not
8137 * compatible with UNION);
8138 * - for ENUMs/ENUM64s, the size is ignored;
8139 * - for INT, size and signedness are ignored;
8140 * - for ARRAY, dimensionality is ignored, element types are checked for
8141 * compatibility recursively;
8142 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
8143 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
8144 * - FUNC_PROTOs are compatible if they have compatible signature: same
8145 * number of input args and compatible return and argument types.
8146 * These rules are not set in stone and probably will be adjusted as we get
8147 * more experience with using BPF CO-RE relocations.
8148 */
8149int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
8150 const struct btf *targ_btf, __u32 targ_id)
8151{
8152 return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
8153 MAX_TYPES_ARE_COMPAT_DEPTH);
8154}
8155
8156#define MAX_TYPES_MATCH_DEPTH 2
8157
8158int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
8159 const struct btf *targ_btf, u32 targ_id)
8160{
8161 return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
8162 MAX_TYPES_MATCH_DEPTH);
8163}
8164
8165static bool bpf_core_is_flavor_sep(const char *s)
8166{
8167 /* check X___Y name pattern, where X and Y are not underscores */
8168 return s[0] != '_' && /* X */
8169 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
8170 s[4] != '_'; /* Y */
8171}
8172
8173size_t bpf_core_essential_name_len(const char *name)
8174{
8175 size_t n = strlen(name);
8176 int i;
8177
8178 for (i = n - 5; i >= 0; i--) {
8179 if (bpf_core_is_flavor_sep(name + i))
8180 return i + 1;
8181 }
8182 return n;
8183}
8184
8185struct bpf_cand_cache {
8186 const char *name;
8187 u32 name_len;
8188 u16 kind;
8189 u16 cnt;
8190 struct {
8191 const struct btf *btf;
8192 u32 id;
8193 } cands[];
8194};
8195
8196static void bpf_free_cands(struct bpf_cand_cache *cands)
8197{
8198 if (!cands->cnt)
8199 /* empty candidate array was allocated on stack */
8200 return;
8201 kfree(cands);
8202}
8203
8204static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
8205{
8206 kfree(cands->name);
8207 kfree(cands);
8208}
8209
8210#define VMLINUX_CAND_CACHE_SIZE 31
8211static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
8212
8213#define MODULE_CAND_CACHE_SIZE 31
8214static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
8215
8216static DEFINE_MUTEX(cand_cache_mutex);
8217
8218static void __print_cand_cache(struct bpf_verifier_log *log,
8219 struct bpf_cand_cache **cache,
8220 int cache_size)
8221{
8222 struct bpf_cand_cache *cc;
8223 int i, j;
8224
8225 for (i = 0; i < cache_size; i++) {
8226 cc = cache[i];
8227 if (!cc)
8228 continue;
8229 bpf_log(log, "[%d]%s(", i, cc->name);
8230 for (j = 0; j < cc->cnt; j++) {
8231 bpf_log(log, "%d", cc->cands[j].id);
8232 if (j < cc->cnt - 1)
8233 bpf_log(log, " ");
8234 }
8235 bpf_log(log, "), ");
8236 }
8237}
8238
8239static void print_cand_cache(struct bpf_verifier_log *log)
8240{
8241 mutex_lock(&cand_cache_mutex);
8242 bpf_log(log, "vmlinux_cand_cache:");
8243 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8244 bpf_log(log, "\nmodule_cand_cache:");
8245 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8246 bpf_log(log, "\n");
8247 mutex_unlock(&cand_cache_mutex);
8248}
8249
8250static u32 hash_cands(struct bpf_cand_cache *cands)
8251{
8252 return jhash(cands->name, cands->name_len, 0);
8253}
8254
8255static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
8256 struct bpf_cand_cache **cache,
8257 int cache_size)
8258{
8259 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
8260
8261 if (cc && cc->name_len == cands->name_len &&
8262 !strncmp(cc->name, cands->name, cands->name_len))
8263 return cc;
8264 return NULL;
8265}
8266
8267static size_t sizeof_cands(int cnt)
8268{
8269 return offsetof(struct bpf_cand_cache, cands[cnt]);
8270}
8271
8272static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
8273 struct bpf_cand_cache **cache,
8274 int cache_size)
8275{
8276 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
8277
8278 if (*cc) {
8279 bpf_free_cands_from_cache(*cc);
8280 *cc = NULL;
8281 }
8282 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
8283 if (!new_cands) {
8284 bpf_free_cands(cands);
8285 return ERR_PTR(-ENOMEM);
8286 }
8287 /* strdup the name, since it will stay in cache.
8288 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
8289 */
8290 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
8291 bpf_free_cands(cands);
8292 if (!new_cands->name) {
8293 kfree(new_cands);
8294 return ERR_PTR(-ENOMEM);
8295 }
8296 *cc = new_cands;
8297 return new_cands;
8298}
8299
8300#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8301static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
8302 int cache_size)
8303{
8304 struct bpf_cand_cache *cc;
8305 int i, j;
8306
8307 for (i = 0; i < cache_size; i++) {
8308 cc = cache[i];
8309 if (!cc)
8310 continue;
8311 if (!btf) {
8312 /* when new module is loaded purge all of module_cand_cache,
8313 * since new module might have candidates with the name
8314 * that matches cached cands.
8315 */
8316 bpf_free_cands_from_cache(cc);
8317 cache[i] = NULL;
8318 continue;
8319 }
8320 /* when module is unloaded purge cache entries
8321 * that match module's btf
8322 */
8323 for (j = 0; j < cc->cnt; j++)
8324 if (cc->cands[j].btf == btf) {
8325 bpf_free_cands_from_cache(cc);
8326 cache[i] = NULL;
8327 break;
8328 }
8329 }
8330
8331}
8332
8333static void purge_cand_cache(struct btf *btf)
8334{
8335 mutex_lock(&cand_cache_mutex);
8336 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8337 mutex_unlock(&cand_cache_mutex);
8338}
8339#endif
8340
8341static struct bpf_cand_cache *
8342bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
8343 int targ_start_id)
8344{
8345 struct bpf_cand_cache *new_cands;
8346 const struct btf_type *t;
8347 const char *targ_name;
8348 size_t targ_essent_len;
8349 int n, i;
8350
8351 n = btf_nr_types(targ_btf);
8352 for (i = targ_start_id; i < n; i++) {
8353 t = btf_type_by_id(targ_btf, i);
8354 if (btf_kind(t) != cands->kind)
8355 continue;
8356
8357 targ_name = btf_name_by_offset(targ_btf, t->name_off);
8358 if (!targ_name)
8359 continue;
8360
8361 /* the resched point is before strncmp to make sure that search
8362 * for non-existing name will have a chance to schedule().
8363 */
8364 cond_resched();
8365
8366 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
8367 continue;
8368
8369 targ_essent_len = bpf_core_essential_name_len(targ_name);
8370 if (targ_essent_len != cands->name_len)
8371 continue;
8372
8373 /* most of the time there is only one candidate for a given kind+name pair */
8374 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
8375 if (!new_cands) {
8376 bpf_free_cands(cands);
8377 return ERR_PTR(-ENOMEM);
8378 }
8379
8380 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
8381 bpf_free_cands(cands);
8382 cands = new_cands;
8383 cands->cands[cands->cnt].btf = targ_btf;
8384 cands->cands[cands->cnt].id = i;
8385 cands->cnt++;
8386 }
8387 return cands;
8388}
8389
8390static struct bpf_cand_cache *
8391bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
8392{
8393 struct bpf_cand_cache *cands, *cc, local_cand = {};
8394 const struct btf *local_btf = ctx->btf;
8395 const struct btf_type *local_type;
8396 const struct btf *main_btf;
8397 size_t local_essent_len;
8398 struct btf *mod_btf;
8399 const char *name;
8400 int id;
8401
8402 main_btf = bpf_get_btf_vmlinux();
8403 if (IS_ERR(main_btf))
8404 return ERR_CAST(main_btf);
8405 if (!main_btf)
8406 return ERR_PTR(-EINVAL);
8407
8408 local_type = btf_type_by_id(local_btf, local_type_id);
8409 if (!local_type)
8410 return ERR_PTR(-EINVAL);
8411
8412 name = btf_name_by_offset(local_btf, local_type->name_off);
8413 if (str_is_empty(name))
8414 return ERR_PTR(-EINVAL);
8415 local_essent_len = bpf_core_essential_name_len(name);
8416
8417 cands = &local_cand;
8418 cands->name = name;
8419 cands->kind = btf_kind(local_type);
8420 cands->name_len = local_essent_len;
8421
8422 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8423 /* cands is a pointer to stack here */
8424 if (cc) {
8425 if (cc->cnt)
8426 return cc;
8427 goto check_modules;
8428 }
8429
8430 /* Attempt to find target candidates in vmlinux BTF first */
8431 cands = bpf_core_add_cands(cands, main_btf, 1);
8432 if (IS_ERR(cands))
8433 return ERR_CAST(cands);
8434
8435 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
8436
8437 /* populate cache even when cands->cnt == 0 */
8438 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8439 if (IS_ERR(cc))
8440 return ERR_CAST(cc);
8441
8442 /* if vmlinux BTF has any candidate, don't go for module BTFs */
8443 if (cc->cnt)
8444 return cc;
8445
8446check_modules:
8447 /* cands is a pointer to stack here and cands->cnt == 0 */
8448 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8449 if (cc)
8450 /* if cache has it return it even if cc->cnt == 0 */
8451 return cc;
8452
8453 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
8454 spin_lock_bh(&btf_idr_lock);
8455 idr_for_each_entry(&btf_idr, mod_btf, id) {
8456 if (!btf_is_module(mod_btf))
8457 continue;
8458 /* linear search could be slow hence unlock/lock
8459 * the IDR to avoiding holding it for too long
8460 */
8461 btf_get(mod_btf);
8462 spin_unlock_bh(&btf_idr_lock);
8463 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
8464 btf_put(mod_btf);
8465 if (IS_ERR(cands))
8466 return ERR_CAST(cands);
8467 spin_lock_bh(&btf_idr_lock);
8468 }
8469 spin_unlock_bh(&btf_idr_lock);
8470 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
8471 * or pointer to stack if cands->cnd == 0.
8472 * Copy it into the cache even when cands->cnt == 0 and
8473 * return the result.
8474 */
8475 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8476}
8477
8478int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
8479 int relo_idx, void *insn)
8480{
8481 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
8482 struct bpf_core_cand_list cands = {};
8483 struct bpf_core_relo_res targ_res;
8484 struct bpf_core_spec *specs;
8485 int err;
8486
8487 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
8488 * into arrays of btf_ids of struct fields and array indices.
8489 */
8490 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
8491 if (!specs)
8492 return -ENOMEM;
8493
8494 if (need_cands) {
8495 struct bpf_cand_cache *cc;
8496 int i;
8497
8498 mutex_lock(&cand_cache_mutex);
8499 cc = bpf_core_find_cands(ctx, relo->type_id);
8500 if (IS_ERR(cc)) {
8501 bpf_log(ctx->log, "target candidate search failed for %d\n",
8502 relo->type_id);
8503 err = PTR_ERR(cc);
8504 goto out;
8505 }
8506 if (cc->cnt) {
8507 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
8508 if (!cands.cands) {
8509 err = -ENOMEM;
8510 goto out;
8511 }
8512 }
8513 for (i = 0; i < cc->cnt; i++) {
8514 bpf_log(ctx->log,
8515 "CO-RE relocating %s %s: found target candidate [%d]\n",
8516 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
8517 cands.cands[i].btf = cc->cands[i].btf;
8518 cands.cands[i].id = cc->cands[i].id;
8519 }
8520 cands.len = cc->cnt;
8521 /* cand_cache_mutex needs to span the cache lookup and
8522 * copy of btf pointer into bpf_core_cand_list,
8523 * since module can be unloaded while bpf_core_calc_relo_insn
8524 * is working with module's btf.
8525 */
8526 }
8527
8528 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
8529 &targ_res);
8530 if (err)
8531 goto out;
8532
8533 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
8534 &targ_res);
8535
8536out:
8537 kfree(specs);
8538 if (need_cands) {
8539 kfree(cands.cands);
8540 mutex_unlock(&cand_cache_mutex);
8541 if (ctx->log->level & BPF_LOG_LEVEL2)
8542 print_cand_cache(ctx->log);
8543 }
8544 return err;
8545}
8546
8547bool btf_nested_type_is_trusted(struct bpf_verifier_log *log,
8548 const struct bpf_reg_state *reg,
8549 const char *field_name, u32 btf_id, const char *suffix)
8550{
8551 struct btf *btf = reg->btf;
8552 const struct btf_type *walk_type, *safe_type;
8553 const char *tname;
8554 char safe_tname[64];
8555 long ret, safe_id;
8556 const struct btf_member *member;
8557 u32 i;
8558
8559 walk_type = btf_type_by_id(btf, reg->btf_id);
8560 if (!walk_type)
8561 return false;
8562
8563 tname = btf_name_by_offset(btf, walk_type->name_off);
8564
8565 ret = snprintf(safe_tname, sizeof(safe_tname), "%s%s", tname, suffix);
8566 if (ret >= sizeof(safe_tname))
8567 return false;
8568
8569 safe_id = btf_find_by_name_kind(btf, safe_tname, BTF_INFO_KIND(walk_type->info));
8570 if (safe_id < 0)
8571 return false;
8572
8573 safe_type = btf_type_by_id(btf, safe_id);
8574 if (!safe_type)
8575 return false;
8576
8577 for_each_member(i, safe_type, member) {
8578 const char *m_name = __btf_name_by_offset(btf, member->name_off);
8579 const struct btf_type *mtype = btf_type_by_id(btf, member->type);
8580 u32 id;
8581
8582 if (!btf_type_is_ptr(mtype))
8583 continue;
8584
8585 btf_type_skip_modifiers(btf, mtype->type, &id);
8586 /* If we match on both type and name, the field is considered trusted. */
8587 if (btf_id == id && !strcmp(field_name, m_name))
8588 return true;
8589 }
8590
8591 return false;
8592}
8593
8594bool btf_type_ids_nocast_alias(struct bpf_verifier_log *log,
8595 const struct btf *reg_btf, u32 reg_id,
8596 const struct btf *arg_btf, u32 arg_id)
8597{
8598 const char *reg_name, *arg_name, *search_needle;
8599 const struct btf_type *reg_type, *arg_type;
8600 int reg_len, arg_len, cmp_len;
8601 size_t pattern_len = sizeof(NOCAST_ALIAS_SUFFIX) - sizeof(char);
8602
8603 reg_type = btf_type_by_id(reg_btf, reg_id);
8604 if (!reg_type)
8605 return false;
8606
8607 arg_type = btf_type_by_id(arg_btf, arg_id);
8608 if (!arg_type)
8609 return false;
8610
8611 reg_name = btf_name_by_offset(reg_btf, reg_type->name_off);
8612 arg_name = btf_name_by_offset(arg_btf, arg_type->name_off);
8613
8614 reg_len = strlen(reg_name);
8615 arg_len = strlen(arg_name);
8616
8617 /* Exactly one of the two type names may be suffixed with ___init, so
8618 * if the strings are the same size, they can't possibly be no-cast
8619 * aliases of one another. If you have two of the same type names, e.g.
8620 * they're both nf_conn___init, it would be improper to return true
8621 * because they are _not_ no-cast aliases, they are the same type.
8622 */
8623 if (reg_len == arg_len)
8624 return false;
8625
8626 /* Either of the two names must be the other name, suffixed with ___init. */
8627 if ((reg_len != arg_len + pattern_len) &&
8628 (arg_len != reg_len + pattern_len))
8629 return false;
8630
8631 if (reg_len < arg_len) {
8632 search_needle = strstr(arg_name, NOCAST_ALIAS_SUFFIX);
8633 cmp_len = reg_len;
8634 } else {
8635 search_needle = strstr(reg_name, NOCAST_ALIAS_SUFFIX);
8636 cmp_len = arg_len;
8637 }
8638
8639 if (!search_needle)
8640 return false;
8641
8642 /* ___init suffix must come at the end of the name */
8643 if (*(search_needle + pattern_len) != '\0')
8644 return false;
8645
8646 return !strncmp(reg_name, arg_name, cmp_len);
8647}
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2018 Facebook */
3
4#include <uapi/linux/btf.h>
5#include <uapi/linux/bpf.h>
6#include <uapi/linux/bpf_perf_event.h>
7#include <uapi/linux/types.h>
8#include <linux/seq_file.h>
9#include <linux/compiler.h>
10#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/slab.h>
13#include <linux/anon_inodes.h>
14#include <linux/file.h>
15#include <linux/uaccess.h>
16#include <linux/kernel.h>
17#include <linux/idr.h>
18#include <linux/sort.h>
19#include <linux/bpf_verifier.h>
20#include <linux/btf.h>
21#include <linux/btf_ids.h>
22#include <linux/bpf.h>
23#include <linux/bpf_lsm.h>
24#include <linux/skmsg.h>
25#include <linux/perf_event.h>
26#include <linux/bsearch.h>
27#include <linux/kobject.h>
28#include <linux/sysfs.h>
29
30#include <net/netfilter/nf_bpf_link.h>
31
32#include <net/sock.h>
33#include <net/xdp.h>
34#include "../tools/lib/bpf/relo_core.h"
35
36/* BTF (BPF Type Format) is the meta data format which describes
37 * the data types of BPF program/map. Hence, it basically focus
38 * on the C programming language which the modern BPF is primary
39 * using.
40 *
41 * ELF Section:
42 * ~~~~~~~~~~~
43 * The BTF data is stored under the ".BTF" ELF section
44 *
45 * struct btf_type:
46 * ~~~~~~~~~~~~~~~
47 * Each 'struct btf_type' object describes a C data type.
48 * Depending on the type it is describing, a 'struct btf_type'
49 * object may be followed by more data. F.e.
50 * To describe an array, 'struct btf_type' is followed by
51 * 'struct btf_array'.
52 *
53 * 'struct btf_type' and any extra data following it are
54 * 4 bytes aligned.
55 *
56 * Type section:
57 * ~~~~~~~~~~~~~
58 * The BTF type section contains a list of 'struct btf_type' objects.
59 * Each one describes a C type. Recall from the above section
60 * that a 'struct btf_type' object could be immediately followed by extra
61 * data in order to describe some particular C types.
62 *
63 * type_id:
64 * ~~~~~~~
65 * Each btf_type object is identified by a type_id. The type_id
66 * is implicitly implied by the location of the btf_type object in
67 * the BTF type section. The first one has type_id 1. The second
68 * one has type_id 2...etc. Hence, an earlier btf_type has
69 * a smaller type_id.
70 *
71 * A btf_type object may refer to another btf_type object by using
72 * type_id (i.e. the "type" in the "struct btf_type").
73 *
74 * NOTE that we cannot assume any reference-order.
75 * A btf_type object can refer to an earlier btf_type object
76 * but it can also refer to a later btf_type object.
77 *
78 * For example, to describe "const void *". A btf_type
79 * object describing "const" may refer to another btf_type
80 * object describing "void *". This type-reference is done
81 * by specifying type_id:
82 *
83 * [1] CONST (anon) type_id=2
84 * [2] PTR (anon) type_id=0
85 *
86 * The above is the btf_verifier debug log:
87 * - Each line started with "[?]" is a btf_type object
88 * - [?] is the type_id of the btf_type object.
89 * - CONST/PTR is the BTF_KIND_XXX
90 * - "(anon)" is the name of the type. It just
91 * happens that CONST and PTR has no name.
92 * - type_id=XXX is the 'u32 type' in btf_type
93 *
94 * NOTE: "void" has type_id 0
95 *
96 * String section:
97 * ~~~~~~~~~~~~~~
98 * The BTF string section contains the names used by the type section.
99 * Each string is referred by an "offset" from the beginning of the
100 * string section.
101 *
102 * Each string is '\0' terminated.
103 *
104 * The first character in the string section must be '\0'
105 * which is used to mean 'anonymous'. Some btf_type may not
106 * have a name.
107 */
108
109/* BTF verification:
110 *
111 * To verify BTF data, two passes are needed.
112 *
113 * Pass #1
114 * ~~~~~~~
115 * The first pass is to collect all btf_type objects to
116 * an array: "btf->types".
117 *
118 * Depending on the C type that a btf_type is describing,
119 * a btf_type may be followed by extra data. We don't know
120 * how many btf_type is there, and more importantly we don't
121 * know where each btf_type is located in the type section.
122 *
123 * Without knowing the location of each type_id, most verifications
124 * cannot be done. e.g. an earlier btf_type may refer to a later
125 * btf_type (recall the "const void *" above), so we cannot
126 * check this type-reference in the first pass.
127 *
128 * In the first pass, it still does some verifications (e.g.
129 * checking the name is a valid offset to the string section).
130 *
131 * Pass #2
132 * ~~~~~~~
133 * The main focus is to resolve a btf_type that is referring
134 * to another type.
135 *
136 * We have to ensure the referring type:
137 * 1) does exist in the BTF (i.e. in btf->types[])
138 * 2) does not cause a loop:
139 * struct A {
140 * struct B b;
141 * };
142 *
143 * struct B {
144 * struct A a;
145 * };
146 *
147 * btf_type_needs_resolve() decides if a btf_type needs
148 * to be resolved.
149 *
150 * The needs_resolve type implements the "resolve()" ops which
151 * essentially does a DFS and detects backedge.
152 *
153 * During resolve (or DFS), different C types have different
154 * "RESOLVED" conditions.
155 *
156 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
157 * members because a member is always referring to another
158 * type. A struct's member can be treated as "RESOLVED" if
159 * it is referring to a BTF_KIND_PTR. Otherwise, the
160 * following valid C struct would be rejected:
161 *
162 * struct A {
163 * int m;
164 * struct A *a;
165 * };
166 *
167 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
168 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
169 * detect a pointer loop, e.g.:
170 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
171 * ^ |
172 * +-----------------------------------------+
173 *
174 */
175
176#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
177#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
178#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
179#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
180#define BITS_ROUNDUP_BYTES(bits) \
181 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
182
183#define BTF_INFO_MASK 0x9f00ffff
184#define BTF_INT_MASK 0x0fffffff
185#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
186#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
187
188/* 16MB for 64k structs and each has 16 members and
189 * a few MB spaces for the string section.
190 * The hard limit is S32_MAX.
191 */
192#define BTF_MAX_SIZE (16 * 1024 * 1024)
193
194#define for_each_member_from(i, from, struct_type, member) \
195 for (i = from, member = btf_type_member(struct_type) + from; \
196 i < btf_type_vlen(struct_type); \
197 i++, member++)
198
199#define for_each_vsi_from(i, from, struct_type, member) \
200 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
201 i < btf_type_vlen(struct_type); \
202 i++, member++)
203
204DEFINE_IDR(btf_idr);
205DEFINE_SPINLOCK(btf_idr_lock);
206
207enum btf_kfunc_hook {
208 BTF_KFUNC_HOOK_COMMON,
209 BTF_KFUNC_HOOK_XDP,
210 BTF_KFUNC_HOOK_TC,
211 BTF_KFUNC_HOOK_STRUCT_OPS,
212 BTF_KFUNC_HOOK_TRACING,
213 BTF_KFUNC_HOOK_SYSCALL,
214 BTF_KFUNC_HOOK_FMODRET,
215 BTF_KFUNC_HOOK_CGROUP_SKB,
216 BTF_KFUNC_HOOK_SCHED_ACT,
217 BTF_KFUNC_HOOK_SK_SKB,
218 BTF_KFUNC_HOOK_SOCKET_FILTER,
219 BTF_KFUNC_HOOK_LWT,
220 BTF_KFUNC_HOOK_NETFILTER,
221 BTF_KFUNC_HOOK_MAX,
222};
223
224enum {
225 BTF_KFUNC_SET_MAX_CNT = 256,
226 BTF_DTOR_KFUNC_MAX_CNT = 256,
227 BTF_KFUNC_FILTER_MAX_CNT = 16,
228};
229
230struct btf_kfunc_hook_filter {
231 btf_kfunc_filter_t filters[BTF_KFUNC_FILTER_MAX_CNT];
232 u32 nr_filters;
233};
234
235struct btf_kfunc_set_tab {
236 struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
237 struct btf_kfunc_hook_filter hook_filters[BTF_KFUNC_HOOK_MAX];
238};
239
240struct btf_id_dtor_kfunc_tab {
241 u32 cnt;
242 struct btf_id_dtor_kfunc dtors[];
243};
244
245struct btf_struct_ops_tab {
246 u32 cnt;
247 u32 capacity;
248 struct bpf_struct_ops_desc ops[];
249};
250
251struct btf {
252 void *data;
253 struct btf_type **types;
254 u32 *resolved_ids;
255 u32 *resolved_sizes;
256 const char *strings;
257 void *nohdr_data;
258 struct btf_header hdr;
259 u32 nr_types; /* includes VOID for base BTF */
260 u32 types_size;
261 u32 data_size;
262 refcount_t refcnt;
263 u32 id;
264 struct rcu_head rcu;
265 struct btf_kfunc_set_tab *kfunc_set_tab;
266 struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
267 struct btf_struct_metas *struct_meta_tab;
268 struct btf_struct_ops_tab *struct_ops_tab;
269
270 /* split BTF support */
271 struct btf *base_btf;
272 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
273 u32 start_str_off; /* first string offset (0 for base BTF) */
274 char name[MODULE_NAME_LEN];
275 bool kernel_btf;
276};
277
278enum verifier_phase {
279 CHECK_META,
280 CHECK_TYPE,
281};
282
283struct resolve_vertex {
284 const struct btf_type *t;
285 u32 type_id;
286 u16 next_member;
287};
288
289enum visit_state {
290 NOT_VISITED,
291 VISITED,
292 RESOLVED,
293};
294
295enum resolve_mode {
296 RESOLVE_TBD, /* To Be Determined */
297 RESOLVE_PTR, /* Resolving for Pointer */
298 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
299 * or array
300 */
301};
302
303#define MAX_RESOLVE_DEPTH 32
304
305struct btf_sec_info {
306 u32 off;
307 u32 len;
308};
309
310struct btf_verifier_env {
311 struct btf *btf;
312 u8 *visit_states;
313 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
314 struct bpf_verifier_log log;
315 u32 log_type_id;
316 u32 top_stack;
317 enum verifier_phase phase;
318 enum resolve_mode resolve_mode;
319};
320
321static const char * const btf_kind_str[NR_BTF_KINDS] = {
322 [BTF_KIND_UNKN] = "UNKNOWN",
323 [BTF_KIND_INT] = "INT",
324 [BTF_KIND_PTR] = "PTR",
325 [BTF_KIND_ARRAY] = "ARRAY",
326 [BTF_KIND_STRUCT] = "STRUCT",
327 [BTF_KIND_UNION] = "UNION",
328 [BTF_KIND_ENUM] = "ENUM",
329 [BTF_KIND_FWD] = "FWD",
330 [BTF_KIND_TYPEDEF] = "TYPEDEF",
331 [BTF_KIND_VOLATILE] = "VOLATILE",
332 [BTF_KIND_CONST] = "CONST",
333 [BTF_KIND_RESTRICT] = "RESTRICT",
334 [BTF_KIND_FUNC] = "FUNC",
335 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
336 [BTF_KIND_VAR] = "VAR",
337 [BTF_KIND_DATASEC] = "DATASEC",
338 [BTF_KIND_FLOAT] = "FLOAT",
339 [BTF_KIND_DECL_TAG] = "DECL_TAG",
340 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
341 [BTF_KIND_ENUM64] = "ENUM64",
342};
343
344const char *btf_type_str(const struct btf_type *t)
345{
346 return btf_kind_str[BTF_INFO_KIND(t->info)];
347}
348
349/* Chunk size we use in safe copy of data to be shown. */
350#define BTF_SHOW_OBJ_SAFE_SIZE 32
351
352/*
353 * This is the maximum size of a base type value (equivalent to a
354 * 128-bit int); if we are at the end of our safe buffer and have
355 * less than 16 bytes space we can't be assured of being able
356 * to copy the next type safely, so in such cases we will initiate
357 * a new copy.
358 */
359#define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
360
361/* Type name size */
362#define BTF_SHOW_NAME_SIZE 80
363
364/*
365 * The suffix of a type that indicates it cannot alias another type when
366 * comparing BTF IDs for kfunc invocations.
367 */
368#define NOCAST_ALIAS_SUFFIX "___init"
369
370/*
371 * Common data to all BTF show operations. Private show functions can add
372 * their own data to a structure containing a struct btf_show and consult it
373 * in the show callback. See btf_type_show() below.
374 *
375 * One challenge with showing nested data is we want to skip 0-valued
376 * data, but in order to figure out whether a nested object is all zeros
377 * we need to walk through it. As a result, we need to make two passes
378 * when handling structs, unions and arrays; the first path simply looks
379 * for nonzero data, while the second actually does the display. The first
380 * pass is signalled by show->state.depth_check being set, and if we
381 * encounter a non-zero value we set show->state.depth_to_show to
382 * the depth at which we encountered it. When we have completed the
383 * first pass, we will know if anything needs to be displayed if
384 * depth_to_show > depth. See btf_[struct,array]_show() for the
385 * implementation of this.
386 *
387 * Another problem is we want to ensure the data for display is safe to
388 * access. To support this, the anonymous "struct {} obj" tracks the data
389 * object and our safe copy of it. We copy portions of the data needed
390 * to the object "copy" buffer, but because its size is limited to
391 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
392 * traverse larger objects for display.
393 *
394 * The various data type show functions all start with a call to
395 * btf_show_start_type() which returns a pointer to the safe copy
396 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
397 * raw data itself). btf_show_obj_safe() is responsible for
398 * using copy_from_kernel_nofault() to update the safe data if necessary
399 * as we traverse the object's data. skbuff-like semantics are
400 * used:
401 *
402 * - obj.head points to the start of the toplevel object for display
403 * - obj.size is the size of the toplevel object
404 * - obj.data points to the current point in the original data at
405 * which our safe data starts. obj.data will advance as we copy
406 * portions of the data.
407 *
408 * In most cases a single copy will suffice, but larger data structures
409 * such as "struct task_struct" will require many copies. The logic in
410 * btf_show_obj_safe() handles the logic that determines if a new
411 * copy_from_kernel_nofault() is needed.
412 */
413struct btf_show {
414 u64 flags;
415 void *target; /* target of show operation (seq file, buffer) */
416 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
417 const struct btf *btf;
418 /* below are used during iteration */
419 struct {
420 u8 depth;
421 u8 depth_to_show;
422 u8 depth_check;
423 u8 array_member:1,
424 array_terminated:1;
425 u16 array_encoding;
426 u32 type_id;
427 int status; /* non-zero for error */
428 const struct btf_type *type;
429 const struct btf_member *member;
430 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
431 } state;
432 struct {
433 u32 size;
434 void *head;
435 void *data;
436 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
437 } obj;
438};
439
440struct btf_kind_operations {
441 s32 (*check_meta)(struct btf_verifier_env *env,
442 const struct btf_type *t,
443 u32 meta_left);
444 int (*resolve)(struct btf_verifier_env *env,
445 const struct resolve_vertex *v);
446 int (*check_member)(struct btf_verifier_env *env,
447 const struct btf_type *struct_type,
448 const struct btf_member *member,
449 const struct btf_type *member_type);
450 int (*check_kflag_member)(struct btf_verifier_env *env,
451 const struct btf_type *struct_type,
452 const struct btf_member *member,
453 const struct btf_type *member_type);
454 void (*log_details)(struct btf_verifier_env *env,
455 const struct btf_type *t);
456 void (*show)(const struct btf *btf, const struct btf_type *t,
457 u32 type_id, void *data, u8 bits_offsets,
458 struct btf_show *show);
459};
460
461static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
462static struct btf_type btf_void;
463
464static int btf_resolve(struct btf_verifier_env *env,
465 const struct btf_type *t, u32 type_id);
466
467static int btf_func_check(struct btf_verifier_env *env,
468 const struct btf_type *t);
469
470static bool btf_type_is_modifier(const struct btf_type *t)
471{
472 /* Some of them is not strictly a C modifier
473 * but they are grouped into the same bucket
474 * for BTF concern:
475 * A type (t) that refers to another
476 * type through t->type AND its size cannot
477 * be determined without following the t->type.
478 *
479 * ptr does not fall into this bucket
480 * because its size is always sizeof(void *).
481 */
482 switch (BTF_INFO_KIND(t->info)) {
483 case BTF_KIND_TYPEDEF:
484 case BTF_KIND_VOLATILE:
485 case BTF_KIND_CONST:
486 case BTF_KIND_RESTRICT:
487 case BTF_KIND_TYPE_TAG:
488 return true;
489 }
490
491 return false;
492}
493
494bool btf_type_is_void(const struct btf_type *t)
495{
496 return t == &btf_void;
497}
498
499static bool btf_type_is_fwd(const struct btf_type *t)
500{
501 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
502}
503
504static bool btf_type_is_datasec(const struct btf_type *t)
505{
506 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
507}
508
509static bool btf_type_is_decl_tag(const struct btf_type *t)
510{
511 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
512}
513
514static bool btf_type_nosize(const struct btf_type *t)
515{
516 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
517 btf_type_is_func(t) || btf_type_is_func_proto(t) ||
518 btf_type_is_decl_tag(t);
519}
520
521static bool btf_type_nosize_or_null(const struct btf_type *t)
522{
523 return !t || btf_type_nosize(t);
524}
525
526static bool btf_type_is_decl_tag_target(const struct btf_type *t)
527{
528 return btf_type_is_func(t) || btf_type_is_struct(t) ||
529 btf_type_is_var(t) || btf_type_is_typedef(t);
530}
531
532u32 btf_nr_types(const struct btf *btf)
533{
534 u32 total = 0;
535
536 while (btf) {
537 total += btf->nr_types;
538 btf = btf->base_btf;
539 }
540
541 return total;
542}
543
544s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
545{
546 const struct btf_type *t;
547 const char *tname;
548 u32 i, total;
549
550 total = btf_nr_types(btf);
551 for (i = 1; i < total; i++) {
552 t = btf_type_by_id(btf, i);
553 if (BTF_INFO_KIND(t->info) != kind)
554 continue;
555
556 tname = btf_name_by_offset(btf, t->name_off);
557 if (!strcmp(tname, name))
558 return i;
559 }
560
561 return -ENOENT;
562}
563
564s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
565{
566 struct btf *btf;
567 s32 ret;
568 int id;
569
570 btf = bpf_get_btf_vmlinux();
571 if (IS_ERR(btf))
572 return PTR_ERR(btf);
573 if (!btf)
574 return -EINVAL;
575
576 ret = btf_find_by_name_kind(btf, name, kind);
577 /* ret is never zero, since btf_find_by_name_kind returns
578 * positive btf_id or negative error.
579 */
580 if (ret > 0) {
581 btf_get(btf);
582 *btf_p = btf;
583 return ret;
584 }
585
586 /* If name is not found in vmlinux's BTF then search in module's BTFs */
587 spin_lock_bh(&btf_idr_lock);
588 idr_for_each_entry(&btf_idr, btf, id) {
589 if (!btf_is_module(btf))
590 continue;
591 /* linear search could be slow hence unlock/lock
592 * the IDR to avoiding holding it for too long
593 */
594 btf_get(btf);
595 spin_unlock_bh(&btf_idr_lock);
596 ret = btf_find_by_name_kind(btf, name, kind);
597 if (ret > 0) {
598 *btf_p = btf;
599 return ret;
600 }
601 btf_put(btf);
602 spin_lock_bh(&btf_idr_lock);
603 }
604 spin_unlock_bh(&btf_idr_lock);
605 return ret;
606}
607
608const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
609 u32 id, u32 *res_id)
610{
611 const struct btf_type *t = btf_type_by_id(btf, id);
612
613 while (btf_type_is_modifier(t)) {
614 id = t->type;
615 t = btf_type_by_id(btf, t->type);
616 }
617
618 if (res_id)
619 *res_id = id;
620
621 return t;
622}
623
624const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
625 u32 id, u32 *res_id)
626{
627 const struct btf_type *t;
628
629 t = btf_type_skip_modifiers(btf, id, NULL);
630 if (!btf_type_is_ptr(t))
631 return NULL;
632
633 return btf_type_skip_modifiers(btf, t->type, res_id);
634}
635
636const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
637 u32 id, u32 *res_id)
638{
639 const struct btf_type *ptype;
640
641 ptype = btf_type_resolve_ptr(btf, id, res_id);
642 if (ptype && btf_type_is_func_proto(ptype))
643 return ptype;
644
645 return NULL;
646}
647
648/* Types that act only as a source, not sink or intermediate
649 * type when resolving.
650 */
651static bool btf_type_is_resolve_source_only(const struct btf_type *t)
652{
653 return btf_type_is_var(t) ||
654 btf_type_is_decl_tag(t) ||
655 btf_type_is_datasec(t);
656}
657
658/* What types need to be resolved?
659 *
660 * btf_type_is_modifier() is an obvious one.
661 *
662 * btf_type_is_struct() because its member refers to
663 * another type (through member->type).
664 *
665 * btf_type_is_var() because the variable refers to
666 * another type. btf_type_is_datasec() holds multiple
667 * btf_type_is_var() types that need resolving.
668 *
669 * btf_type_is_array() because its element (array->type)
670 * refers to another type. Array can be thought of a
671 * special case of struct while array just has the same
672 * member-type repeated by array->nelems of times.
673 */
674static bool btf_type_needs_resolve(const struct btf_type *t)
675{
676 return btf_type_is_modifier(t) ||
677 btf_type_is_ptr(t) ||
678 btf_type_is_struct(t) ||
679 btf_type_is_array(t) ||
680 btf_type_is_var(t) ||
681 btf_type_is_func(t) ||
682 btf_type_is_decl_tag(t) ||
683 btf_type_is_datasec(t);
684}
685
686/* t->size can be used */
687static bool btf_type_has_size(const struct btf_type *t)
688{
689 switch (BTF_INFO_KIND(t->info)) {
690 case BTF_KIND_INT:
691 case BTF_KIND_STRUCT:
692 case BTF_KIND_UNION:
693 case BTF_KIND_ENUM:
694 case BTF_KIND_DATASEC:
695 case BTF_KIND_FLOAT:
696 case BTF_KIND_ENUM64:
697 return true;
698 }
699
700 return false;
701}
702
703static const char *btf_int_encoding_str(u8 encoding)
704{
705 if (encoding == 0)
706 return "(none)";
707 else if (encoding == BTF_INT_SIGNED)
708 return "SIGNED";
709 else if (encoding == BTF_INT_CHAR)
710 return "CHAR";
711 else if (encoding == BTF_INT_BOOL)
712 return "BOOL";
713 else
714 return "UNKN";
715}
716
717static u32 btf_type_int(const struct btf_type *t)
718{
719 return *(u32 *)(t + 1);
720}
721
722static const struct btf_array *btf_type_array(const struct btf_type *t)
723{
724 return (const struct btf_array *)(t + 1);
725}
726
727static const struct btf_enum *btf_type_enum(const struct btf_type *t)
728{
729 return (const struct btf_enum *)(t + 1);
730}
731
732static const struct btf_var *btf_type_var(const struct btf_type *t)
733{
734 return (const struct btf_var *)(t + 1);
735}
736
737static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
738{
739 return (const struct btf_decl_tag *)(t + 1);
740}
741
742static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
743{
744 return (const struct btf_enum64 *)(t + 1);
745}
746
747static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
748{
749 return kind_ops[BTF_INFO_KIND(t->info)];
750}
751
752static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
753{
754 if (!BTF_STR_OFFSET_VALID(offset))
755 return false;
756
757 while (offset < btf->start_str_off)
758 btf = btf->base_btf;
759
760 offset -= btf->start_str_off;
761 return offset < btf->hdr.str_len;
762}
763
764static bool __btf_name_char_ok(char c, bool first)
765{
766 if ((first ? !isalpha(c) :
767 !isalnum(c)) &&
768 c != '_' &&
769 c != '.')
770 return false;
771 return true;
772}
773
774static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
775{
776 while (offset < btf->start_str_off)
777 btf = btf->base_btf;
778
779 offset -= btf->start_str_off;
780 if (offset < btf->hdr.str_len)
781 return &btf->strings[offset];
782
783 return NULL;
784}
785
786static bool __btf_name_valid(const struct btf *btf, u32 offset)
787{
788 /* offset must be valid */
789 const char *src = btf_str_by_offset(btf, offset);
790 const char *src_limit;
791
792 if (!__btf_name_char_ok(*src, true))
793 return false;
794
795 /* set a limit on identifier length */
796 src_limit = src + KSYM_NAME_LEN;
797 src++;
798 while (*src && src < src_limit) {
799 if (!__btf_name_char_ok(*src, false))
800 return false;
801 src++;
802 }
803
804 return !*src;
805}
806
807static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
808{
809 return __btf_name_valid(btf, offset);
810}
811
812/* Allow any printable character in DATASEC names */
813static bool btf_name_valid_section(const struct btf *btf, u32 offset)
814{
815 /* offset must be valid */
816 const char *src = btf_str_by_offset(btf, offset);
817 const char *src_limit;
818
819 /* set a limit on identifier length */
820 src_limit = src + KSYM_NAME_LEN;
821 src++;
822 while (*src && src < src_limit) {
823 if (!isprint(*src))
824 return false;
825 src++;
826 }
827
828 return !*src;
829}
830
831static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
832{
833 const char *name;
834
835 if (!offset)
836 return "(anon)";
837
838 name = btf_str_by_offset(btf, offset);
839 return name ?: "(invalid-name-offset)";
840}
841
842const char *btf_name_by_offset(const struct btf *btf, u32 offset)
843{
844 return btf_str_by_offset(btf, offset);
845}
846
847const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
848{
849 while (type_id < btf->start_id)
850 btf = btf->base_btf;
851
852 type_id -= btf->start_id;
853 if (type_id >= btf->nr_types)
854 return NULL;
855 return btf->types[type_id];
856}
857EXPORT_SYMBOL_GPL(btf_type_by_id);
858
859/*
860 * Regular int is not a bit field and it must be either
861 * u8/u16/u32/u64 or __int128.
862 */
863static bool btf_type_int_is_regular(const struct btf_type *t)
864{
865 u8 nr_bits, nr_bytes;
866 u32 int_data;
867
868 int_data = btf_type_int(t);
869 nr_bits = BTF_INT_BITS(int_data);
870 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
871 if (BITS_PER_BYTE_MASKED(nr_bits) ||
872 BTF_INT_OFFSET(int_data) ||
873 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
874 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
875 nr_bytes != (2 * sizeof(u64)))) {
876 return false;
877 }
878
879 return true;
880}
881
882/*
883 * Check that given struct member is a regular int with expected
884 * offset and size.
885 */
886bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
887 const struct btf_member *m,
888 u32 expected_offset, u32 expected_size)
889{
890 const struct btf_type *t;
891 u32 id, int_data;
892 u8 nr_bits;
893
894 id = m->type;
895 t = btf_type_id_size(btf, &id, NULL);
896 if (!t || !btf_type_is_int(t))
897 return false;
898
899 int_data = btf_type_int(t);
900 nr_bits = BTF_INT_BITS(int_data);
901 if (btf_type_kflag(s)) {
902 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
903 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
904
905 /* if kflag set, int should be a regular int and
906 * bit offset should be at byte boundary.
907 */
908 return !bitfield_size &&
909 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
910 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
911 }
912
913 if (BTF_INT_OFFSET(int_data) ||
914 BITS_PER_BYTE_MASKED(m->offset) ||
915 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
916 BITS_PER_BYTE_MASKED(nr_bits) ||
917 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
918 return false;
919
920 return true;
921}
922
923/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
924static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
925 u32 id)
926{
927 const struct btf_type *t = btf_type_by_id(btf, id);
928
929 while (btf_type_is_modifier(t) &&
930 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
931 t = btf_type_by_id(btf, t->type);
932 }
933
934 return t;
935}
936
937#define BTF_SHOW_MAX_ITER 10
938
939#define BTF_KIND_BIT(kind) (1ULL << kind)
940
941/*
942 * Populate show->state.name with type name information.
943 * Format of type name is
944 *
945 * [.member_name = ] (type_name)
946 */
947static const char *btf_show_name(struct btf_show *show)
948{
949 /* BTF_MAX_ITER array suffixes "[]" */
950 const char *array_suffixes = "[][][][][][][][][][]";
951 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
952 /* BTF_MAX_ITER pointer suffixes "*" */
953 const char *ptr_suffixes = "**********";
954 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
955 const char *name = NULL, *prefix = "", *parens = "";
956 const struct btf_member *m = show->state.member;
957 const struct btf_type *t;
958 const struct btf_array *array;
959 u32 id = show->state.type_id;
960 const char *member = NULL;
961 bool show_member = false;
962 u64 kinds = 0;
963 int i;
964
965 show->state.name[0] = '\0';
966
967 /*
968 * Don't show type name if we're showing an array member;
969 * in that case we show the array type so don't need to repeat
970 * ourselves for each member.
971 */
972 if (show->state.array_member)
973 return "";
974
975 /* Retrieve member name, if any. */
976 if (m) {
977 member = btf_name_by_offset(show->btf, m->name_off);
978 show_member = strlen(member) > 0;
979 id = m->type;
980 }
981
982 /*
983 * Start with type_id, as we have resolved the struct btf_type *
984 * via btf_modifier_show() past the parent typedef to the child
985 * struct, int etc it is defined as. In such cases, the type_id
986 * still represents the starting type while the struct btf_type *
987 * in our show->state points at the resolved type of the typedef.
988 */
989 t = btf_type_by_id(show->btf, id);
990 if (!t)
991 return "";
992
993 /*
994 * The goal here is to build up the right number of pointer and
995 * array suffixes while ensuring the type name for a typedef
996 * is represented. Along the way we accumulate a list of
997 * BTF kinds we have encountered, since these will inform later
998 * display; for example, pointer types will not require an
999 * opening "{" for struct, we will just display the pointer value.
1000 *
1001 * We also want to accumulate the right number of pointer or array
1002 * indices in the format string while iterating until we get to
1003 * the typedef/pointee/array member target type.
1004 *
1005 * We start by pointing at the end of pointer and array suffix
1006 * strings; as we accumulate pointers and arrays we move the pointer
1007 * or array string backwards so it will show the expected number of
1008 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
1009 * and/or arrays and typedefs are supported as a precaution.
1010 *
1011 * We also want to get typedef name while proceeding to resolve
1012 * type it points to so that we can add parentheses if it is a
1013 * "typedef struct" etc.
1014 */
1015 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
1016
1017 switch (BTF_INFO_KIND(t->info)) {
1018 case BTF_KIND_TYPEDEF:
1019 if (!name)
1020 name = btf_name_by_offset(show->btf,
1021 t->name_off);
1022 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
1023 id = t->type;
1024 break;
1025 case BTF_KIND_ARRAY:
1026 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
1027 parens = "[";
1028 if (!t)
1029 return "";
1030 array = btf_type_array(t);
1031 if (array_suffix > array_suffixes)
1032 array_suffix -= 2;
1033 id = array->type;
1034 break;
1035 case BTF_KIND_PTR:
1036 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
1037 if (ptr_suffix > ptr_suffixes)
1038 ptr_suffix -= 1;
1039 id = t->type;
1040 break;
1041 default:
1042 id = 0;
1043 break;
1044 }
1045 if (!id)
1046 break;
1047 t = btf_type_skip_qualifiers(show->btf, id);
1048 }
1049 /* We may not be able to represent this type; bail to be safe */
1050 if (i == BTF_SHOW_MAX_ITER)
1051 return "";
1052
1053 if (!name)
1054 name = btf_name_by_offset(show->btf, t->name_off);
1055
1056 switch (BTF_INFO_KIND(t->info)) {
1057 case BTF_KIND_STRUCT:
1058 case BTF_KIND_UNION:
1059 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1060 "struct" : "union";
1061 /* if it's an array of struct/union, parens is already set */
1062 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1063 parens = "{";
1064 break;
1065 case BTF_KIND_ENUM:
1066 case BTF_KIND_ENUM64:
1067 prefix = "enum";
1068 break;
1069 default:
1070 break;
1071 }
1072
1073 /* pointer does not require parens */
1074 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1075 parens = "";
1076 /* typedef does not require struct/union/enum prefix */
1077 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1078 prefix = "";
1079
1080 if (!name)
1081 name = "";
1082
1083 /* Even if we don't want type name info, we want parentheses etc */
1084 if (show->flags & BTF_SHOW_NONAME)
1085 snprintf(show->state.name, sizeof(show->state.name), "%s",
1086 parens);
1087 else
1088 snprintf(show->state.name, sizeof(show->state.name),
1089 "%s%s%s(%s%s%s%s%s%s)%s",
1090 /* first 3 strings comprise ".member = " */
1091 show_member ? "." : "",
1092 show_member ? member : "",
1093 show_member ? " = " : "",
1094 /* ...next is our prefix (struct, enum, etc) */
1095 prefix,
1096 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1097 /* ...this is the type name itself */
1098 name,
1099 /* ...suffixed by the appropriate '*', '[]' suffixes */
1100 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1101 array_suffix, parens);
1102
1103 return show->state.name;
1104}
1105
1106static const char *__btf_show_indent(struct btf_show *show)
1107{
1108 const char *indents = " ";
1109 const char *indent = &indents[strlen(indents)];
1110
1111 if ((indent - show->state.depth) >= indents)
1112 return indent - show->state.depth;
1113 return indents;
1114}
1115
1116static const char *btf_show_indent(struct btf_show *show)
1117{
1118 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1119}
1120
1121static const char *btf_show_newline(struct btf_show *show)
1122{
1123 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1124}
1125
1126static const char *btf_show_delim(struct btf_show *show)
1127{
1128 if (show->state.depth == 0)
1129 return "";
1130
1131 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1132 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1133 return "|";
1134
1135 return ",";
1136}
1137
1138__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1139{
1140 va_list args;
1141
1142 if (!show->state.depth_check) {
1143 va_start(args, fmt);
1144 show->showfn(show, fmt, args);
1145 va_end(args);
1146 }
1147}
1148
1149/* Macros are used here as btf_show_type_value[s]() prepends and appends
1150 * format specifiers to the format specifier passed in; these do the work of
1151 * adding indentation, delimiters etc while the caller simply has to specify
1152 * the type value(s) in the format specifier + value(s).
1153 */
1154#define btf_show_type_value(show, fmt, value) \
1155 do { \
1156 if ((value) != (__typeof__(value))0 || \
1157 (show->flags & BTF_SHOW_ZERO) || \
1158 show->state.depth == 0) { \
1159 btf_show(show, "%s%s" fmt "%s%s", \
1160 btf_show_indent(show), \
1161 btf_show_name(show), \
1162 value, btf_show_delim(show), \
1163 btf_show_newline(show)); \
1164 if (show->state.depth > show->state.depth_to_show) \
1165 show->state.depth_to_show = show->state.depth; \
1166 } \
1167 } while (0)
1168
1169#define btf_show_type_values(show, fmt, ...) \
1170 do { \
1171 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1172 btf_show_name(show), \
1173 __VA_ARGS__, btf_show_delim(show), \
1174 btf_show_newline(show)); \
1175 if (show->state.depth > show->state.depth_to_show) \
1176 show->state.depth_to_show = show->state.depth; \
1177 } while (0)
1178
1179/* How much is left to copy to safe buffer after @data? */
1180static int btf_show_obj_size_left(struct btf_show *show, void *data)
1181{
1182 return show->obj.head + show->obj.size - data;
1183}
1184
1185/* Is object pointed to by @data of @size already copied to our safe buffer? */
1186static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1187{
1188 return data >= show->obj.data &&
1189 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1190}
1191
1192/*
1193 * If object pointed to by @data of @size falls within our safe buffer, return
1194 * the equivalent pointer to the same safe data. Assumes
1195 * copy_from_kernel_nofault() has already happened and our safe buffer is
1196 * populated.
1197 */
1198static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1199{
1200 if (btf_show_obj_is_safe(show, data, size))
1201 return show->obj.safe + (data - show->obj.data);
1202 return NULL;
1203}
1204
1205/*
1206 * Return a safe-to-access version of data pointed to by @data.
1207 * We do this by copying the relevant amount of information
1208 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1209 *
1210 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1211 * safe copy is needed.
1212 *
1213 * Otherwise we need to determine if we have the required amount
1214 * of data (determined by the @data pointer and the size of the
1215 * largest base type we can encounter (represented by
1216 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1217 * that we will be able to print some of the current object,
1218 * and if more is needed a copy will be triggered.
1219 * Some objects such as structs will not fit into the buffer;
1220 * in such cases additional copies when we iterate over their
1221 * members may be needed.
1222 *
1223 * btf_show_obj_safe() is used to return a safe buffer for
1224 * btf_show_start_type(); this ensures that as we recurse into
1225 * nested types we always have safe data for the given type.
1226 * This approach is somewhat wasteful; it's possible for example
1227 * that when iterating over a large union we'll end up copying the
1228 * same data repeatedly, but the goal is safety not performance.
1229 * We use stack data as opposed to per-CPU buffers because the
1230 * iteration over a type can take some time, and preemption handling
1231 * would greatly complicate use of the safe buffer.
1232 */
1233static void *btf_show_obj_safe(struct btf_show *show,
1234 const struct btf_type *t,
1235 void *data)
1236{
1237 const struct btf_type *rt;
1238 int size_left, size;
1239 void *safe = NULL;
1240
1241 if (show->flags & BTF_SHOW_UNSAFE)
1242 return data;
1243
1244 rt = btf_resolve_size(show->btf, t, &size);
1245 if (IS_ERR(rt)) {
1246 show->state.status = PTR_ERR(rt);
1247 return NULL;
1248 }
1249
1250 /*
1251 * Is this toplevel object? If so, set total object size and
1252 * initialize pointers. Otherwise check if we still fall within
1253 * our safe object data.
1254 */
1255 if (show->state.depth == 0) {
1256 show->obj.size = size;
1257 show->obj.head = data;
1258 } else {
1259 /*
1260 * If the size of the current object is > our remaining
1261 * safe buffer we _may_ need to do a new copy. However
1262 * consider the case of a nested struct; it's size pushes
1263 * us over the safe buffer limit, but showing any individual
1264 * struct members does not. In such cases, we don't need
1265 * to initiate a fresh copy yet; however we definitely need
1266 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1267 * in our buffer, regardless of the current object size.
1268 * The logic here is that as we resolve types we will
1269 * hit a base type at some point, and we need to be sure
1270 * the next chunk of data is safely available to display
1271 * that type info safely. We cannot rely on the size of
1272 * the current object here because it may be much larger
1273 * than our current buffer (e.g. task_struct is 8k).
1274 * All we want to do here is ensure that we can print the
1275 * next basic type, which we can if either
1276 * - the current type size is within the safe buffer; or
1277 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1278 * the safe buffer.
1279 */
1280 safe = __btf_show_obj_safe(show, data,
1281 min(size,
1282 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1283 }
1284
1285 /*
1286 * We need a new copy to our safe object, either because we haven't
1287 * yet copied and are initializing safe data, or because the data
1288 * we want falls outside the boundaries of the safe object.
1289 */
1290 if (!safe) {
1291 size_left = btf_show_obj_size_left(show, data);
1292 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1293 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1294 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1295 data, size_left);
1296 if (!show->state.status) {
1297 show->obj.data = data;
1298 safe = show->obj.safe;
1299 }
1300 }
1301
1302 return safe;
1303}
1304
1305/*
1306 * Set the type we are starting to show and return a safe data pointer
1307 * to be used for showing the associated data.
1308 */
1309static void *btf_show_start_type(struct btf_show *show,
1310 const struct btf_type *t,
1311 u32 type_id, void *data)
1312{
1313 show->state.type = t;
1314 show->state.type_id = type_id;
1315 show->state.name[0] = '\0';
1316
1317 return btf_show_obj_safe(show, t, data);
1318}
1319
1320static void btf_show_end_type(struct btf_show *show)
1321{
1322 show->state.type = NULL;
1323 show->state.type_id = 0;
1324 show->state.name[0] = '\0';
1325}
1326
1327static void *btf_show_start_aggr_type(struct btf_show *show,
1328 const struct btf_type *t,
1329 u32 type_id, void *data)
1330{
1331 void *safe_data = btf_show_start_type(show, t, type_id, data);
1332
1333 if (!safe_data)
1334 return safe_data;
1335
1336 btf_show(show, "%s%s%s", btf_show_indent(show),
1337 btf_show_name(show),
1338 btf_show_newline(show));
1339 show->state.depth++;
1340 return safe_data;
1341}
1342
1343static void btf_show_end_aggr_type(struct btf_show *show,
1344 const char *suffix)
1345{
1346 show->state.depth--;
1347 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1348 btf_show_delim(show), btf_show_newline(show));
1349 btf_show_end_type(show);
1350}
1351
1352static void btf_show_start_member(struct btf_show *show,
1353 const struct btf_member *m)
1354{
1355 show->state.member = m;
1356}
1357
1358static void btf_show_start_array_member(struct btf_show *show)
1359{
1360 show->state.array_member = 1;
1361 btf_show_start_member(show, NULL);
1362}
1363
1364static void btf_show_end_member(struct btf_show *show)
1365{
1366 show->state.member = NULL;
1367}
1368
1369static void btf_show_end_array_member(struct btf_show *show)
1370{
1371 show->state.array_member = 0;
1372 btf_show_end_member(show);
1373}
1374
1375static void *btf_show_start_array_type(struct btf_show *show,
1376 const struct btf_type *t,
1377 u32 type_id,
1378 u16 array_encoding,
1379 void *data)
1380{
1381 show->state.array_encoding = array_encoding;
1382 show->state.array_terminated = 0;
1383 return btf_show_start_aggr_type(show, t, type_id, data);
1384}
1385
1386static void btf_show_end_array_type(struct btf_show *show)
1387{
1388 show->state.array_encoding = 0;
1389 show->state.array_terminated = 0;
1390 btf_show_end_aggr_type(show, "]");
1391}
1392
1393static void *btf_show_start_struct_type(struct btf_show *show,
1394 const struct btf_type *t,
1395 u32 type_id,
1396 void *data)
1397{
1398 return btf_show_start_aggr_type(show, t, type_id, data);
1399}
1400
1401static void btf_show_end_struct_type(struct btf_show *show)
1402{
1403 btf_show_end_aggr_type(show, "}");
1404}
1405
1406__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1407 const char *fmt, ...)
1408{
1409 va_list args;
1410
1411 va_start(args, fmt);
1412 bpf_verifier_vlog(log, fmt, args);
1413 va_end(args);
1414}
1415
1416__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1417 const char *fmt, ...)
1418{
1419 struct bpf_verifier_log *log = &env->log;
1420 va_list args;
1421
1422 if (!bpf_verifier_log_needed(log))
1423 return;
1424
1425 va_start(args, fmt);
1426 bpf_verifier_vlog(log, fmt, args);
1427 va_end(args);
1428}
1429
1430__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1431 const struct btf_type *t,
1432 bool log_details,
1433 const char *fmt, ...)
1434{
1435 struct bpf_verifier_log *log = &env->log;
1436 struct btf *btf = env->btf;
1437 va_list args;
1438
1439 if (!bpf_verifier_log_needed(log))
1440 return;
1441
1442 if (log->level == BPF_LOG_KERNEL) {
1443 /* btf verifier prints all types it is processing via
1444 * btf_verifier_log_type(..., fmt = NULL).
1445 * Skip those prints for in-kernel BTF verification.
1446 */
1447 if (!fmt)
1448 return;
1449
1450 /* Skip logging when loading module BTF with mismatches permitted */
1451 if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1452 return;
1453 }
1454
1455 __btf_verifier_log(log, "[%u] %s %s%s",
1456 env->log_type_id,
1457 btf_type_str(t),
1458 __btf_name_by_offset(btf, t->name_off),
1459 log_details ? " " : "");
1460
1461 if (log_details)
1462 btf_type_ops(t)->log_details(env, t);
1463
1464 if (fmt && *fmt) {
1465 __btf_verifier_log(log, " ");
1466 va_start(args, fmt);
1467 bpf_verifier_vlog(log, fmt, args);
1468 va_end(args);
1469 }
1470
1471 __btf_verifier_log(log, "\n");
1472}
1473
1474#define btf_verifier_log_type(env, t, ...) \
1475 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1476#define btf_verifier_log_basic(env, t, ...) \
1477 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1478
1479__printf(4, 5)
1480static void btf_verifier_log_member(struct btf_verifier_env *env,
1481 const struct btf_type *struct_type,
1482 const struct btf_member *member,
1483 const char *fmt, ...)
1484{
1485 struct bpf_verifier_log *log = &env->log;
1486 struct btf *btf = env->btf;
1487 va_list args;
1488
1489 if (!bpf_verifier_log_needed(log))
1490 return;
1491
1492 if (log->level == BPF_LOG_KERNEL) {
1493 if (!fmt)
1494 return;
1495
1496 /* Skip logging when loading module BTF with mismatches permitted */
1497 if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1498 return;
1499 }
1500
1501 /* The CHECK_META phase already did a btf dump.
1502 *
1503 * If member is logged again, it must hit an error in
1504 * parsing this member. It is useful to print out which
1505 * struct this member belongs to.
1506 */
1507 if (env->phase != CHECK_META)
1508 btf_verifier_log_type(env, struct_type, NULL);
1509
1510 if (btf_type_kflag(struct_type))
1511 __btf_verifier_log(log,
1512 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1513 __btf_name_by_offset(btf, member->name_off),
1514 member->type,
1515 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1516 BTF_MEMBER_BIT_OFFSET(member->offset));
1517 else
1518 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1519 __btf_name_by_offset(btf, member->name_off),
1520 member->type, member->offset);
1521
1522 if (fmt && *fmt) {
1523 __btf_verifier_log(log, " ");
1524 va_start(args, fmt);
1525 bpf_verifier_vlog(log, fmt, args);
1526 va_end(args);
1527 }
1528
1529 __btf_verifier_log(log, "\n");
1530}
1531
1532__printf(4, 5)
1533static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1534 const struct btf_type *datasec_type,
1535 const struct btf_var_secinfo *vsi,
1536 const char *fmt, ...)
1537{
1538 struct bpf_verifier_log *log = &env->log;
1539 va_list args;
1540
1541 if (!bpf_verifier_log_needed(log))
1542 return;
1543 if (log->level == BPF_LOG_KERNEL && !fmt)
1544 return;
1545 if (env->phase != CHECK_META)
1546 btf_verifier_log_type(env, datasec_type, NULL);
1547
1548 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1549 vsi->type, vsi->offset, vsi->size);
1550 if (fmt && *fmt) {
1551 __btf_verifier_log(log, " ");
1552 va_start(args, fmt);
1553 bpf_verifier_vlog(log, fmt, args);
1554 va_end(args);
1555 }
1556
1557 __btf_verifier_log(log, "\n");
1558}
1559
1560static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1561 u32 btf_data_size)
1562{
1563 struct bpf_verifier_log *log = &env->log;
1564 const struct btf *btf = env->btf;
1565 const struct btf_header *hdr;
1566
1567 if (!bpf_verifier_log_needed(log))
1568 return;
1569
1570 if (log->level == BPF_LOG_KERNEL)
1571 return;
1572 hdr = &btf->hdr;
1573 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1574 __btf_verifier_log(log, "version: %u\n", hdr->version);
1575 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1576 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1577 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1578 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1579 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1580 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1581 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1582}
1583
1584static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1585{
1586 struct btf *btf = env->btf;
1587
1588 if (btf->types_size == btf->nr_types) {
1589 /* Expand 'types' array */
1590
1591 struct btf_type **new_types;
1592 u32 expand_by, new_size;
1593
1594 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1595 btf_verifier_log(env, "Exceeded max num of types");
1596 return -E2BIG;
1597 }
1598
1599 expand_by = max_t(u32, btf->types_size >> 2, 16);
1600 new_size = min_t(u32, BTF_MAX_TYPE,
1601 btf->types_size + expand_by);
1602
1603 new_types = kvcalloc(new_size, sizeof(*new_types),
1604 GFP_KERNEL | __GFP_NOWARN);
1605 if (!new_types)
1606 return -ENOMEM;
1607
1608 if (btf->nr_types == 0) {
1609 if (!btf->base_btf) {
1610 /* lazily init VOID type */
1611 new_types[0] = &btf_void;
1612 btf->nr_types++;
1613 }
1614 } else {
1615 memcpy(new_types, btf->types,
1616 sizeof(*btf->types) * btf->nr_types);
1617 }
1618
1619 kvfree(btf->types);
1620 btf->types = new_types;
1621 btf->types_size = new_size;
1622 }
1623
1624 btf->types[btf->nr_types++] = t;
1625
1626 return 0;
1627}
1628
1629static int btf_alloc_id(struct btf *btf)
1630{
1631 int id;
1632
1633 idr_preload(GFP_KERNEL);
1634 spin_lock_bh(&btf_idr_lock);
1635 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1636 if (id > 0)
1637 btf->id = id;
1638 spin_unlock_bh(&btf_idr_lock);
1639 idr_preload_end();
1640
1641 if (WARN_ON_ONCE(!id))
1642 return -ENOSPC;
1643
1644 return id > 0 ? 0 : id;
1645}
1646
1647static void btf_free_id(struct btf *btf)
1648{
1649 unsigned long flags;
1650
1651 /*
1652 * In map-in-map, calling map_delete_elem() on outer
1653 * map will call bpf_map_put on the inner map.
1654 * It will then eventually call btf_free_id()
1655 * on the inner map. Some of the map_delete_elem()
1656 * implementation may have irq disabled, so
1657 * we need to use the _irqsave() version instead
1658 * of the _bh() version.
1659 */
1660 spin_lock_irqsave(&btf_idr_lock, flags);
1661 idr_remove(&btf_idr, btf->id);
1662 spin_unlock_irqrestore(&btf_idr_lock, flags);
1663}
1664
1665static void btf_free_kfunc_set_tab(struct btf *btf)
1666{
1667 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1668 int hook;
1669
1670 if (!tab)
1671 return;
1672 /* For module BTF, we directly assign the sets being registered, so
1673 * there is nothing to free except kfunc_set_tab.
1674 */
1675 if (btf_is_module(btf))
1676 goto free_tab;
1677 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1678 kfree(tab->sets[hook]);
1679free_tab:
1680 kfree(tab);
1681 btf->kfunc_set_tab = NULL;
1682}
1683
1684static void btf_free_dtor_kfunc_tab(struct btf *btf)
1685{
1686 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1687
1688 if (!tab)
1689 return;
1690 kfree(tab);
1691 btf->dtor_kfunc_tab = NULL;
1692}
1693
1694static void btf_struct_metas_free(struct btf_struct_metas *tab)
1695{
1696 int i;
1697
1698 if (!tab)
1699 return;
1700 for (i = 0; i < tab->cnt; i++)
1701 btf_record_free(tab->types[i].record);
1702 kfree(tab);
1703}
1704
1705static void btf_free_struct_meta_tab(struct btf *btf)
1706{
1707 struct btf_struct_metas *tab = btf->struct_meta_tab;
1708
1709 btf_struct_metas_free(tab);
1710 btf->struct_meta_tab = NULL;
1711}
1712
1713static void btf_free_struct_ops_tab(struct btf *btf)
1714{
1715 struct btf_struct_ops_tab *tab = btf->struct_ops_tab;
1716 u32 i;
1717
1718 if (!tab)
1719 return;
1720
1721 for (i = 0; i < tab->cnt; i++)
1722 bpf_struct_ops_desc_release(&tab->ops[i]);
1723
1724 kfree(tab);
1725 btf->struct_ops_tab = NULL;
1726}
1727
1728static void btf_free(struct btf *btf)
1729{
1730 btf_free_struct_meta_tab(btf);
1731 btf_free_dtor_kfunc_tab(btf);
1732 btf_free_kfunc_set_tab(btf);
1733 btf_free_struct_ops_tab(btf);
1734 kvfree(btf->types);
1735 kvfree(btf->resolved_sizes);
1736 kvfree(btf->resolved_ids);
1737 kvfree(btf->data);
1738 kfree(btf);
1739}
1740
1741static void btf_free_rcu(struct rcu_head *rcu)
1742{
1743 struct btf *btf = container_of(rcu, struct btf, rcu);
1744
1745 btf_free(btf);
1746}
1747
1748const char *btf_get_name(const struct btf *btf)
1749{
1750 return btf->name;
1751}
1752
1753void btf_get(struct btf *btf)
1754{
1755 refcount_inc(&btf->refcnt);
1756}
1757
1758void btf_put(struct btf *btf)
1759{
1760 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1761 btf_free_id(btf);
1762 call_rcu(&btf->rcu, btf_free_rcu);
1763 }
1764}
1765
1766static int env_resolve_init(struct btf_verifier_env *env)
1767{
1768 struct btf *btf = env->btf;
1769 u32 nr_types = btf->nr_types;
1770 u32 *resolved_sizes = NULL;
1771 u32 *resolved_ids = NULL;
1772 u8 *visit_states = NULL;
1773
1774 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1775 GFP_KERNEL | __GFP_NOWARN);
1776 if (!resolved_sizes)
1777 goto nomem;
1778
1779 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1780 GFP_KERNEL | __GFP_NOWARN);
1781 if (!resolved_ids)
1782 goto nomem;
1783
1784 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1785 GFP_KERNEL | __GFP_NOWARN);
1786 if (!visit_states)
1787 goto nomem;
1788
1789 btf->resolved_sizes = resolved_sizes;
1790 btf->resolved_ids = resolved_ids;
1791 env->visit_states = visit_states;
1792
1793 return 0;
1794
1795nomem:
1796 kvfree(resolved_sizes);
1797 kvfree(resolved_ids);
1798 kvfree(visit_states);
1799 return -ENOMEM;
1800}
1801
1802static void btf_verifier_env_free(struct btf_verifier_env *env)
1803{
1804 kvfree(env->visit_states);
1805 kfree(env);
1806}
1807
1808static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1809 const struct btf_type *next_type)
1810{
1811 switch (env->resolve_mode) {
1812 case RESOLVE_TBD:
1813 /* int, enum or void is a sink */
1814 return !btf_type_needs_resolve(next_type);
1815 case RESOLVE_PTR:
1816 /* int, enum, void, struct, array, func or func_proto is a sink
1817 * for ptr
1818 */
1819 return !btf_type_is_modifier(next_type) &&
1820 !btf_type_is_ptr(next_type);
1821 case RESOLVE_STRUCT_OR_ARRAY:
1822 /* int, enum, void, ptr, func or func_proto is a sink
1823 * for struct and array
1824 */
1825 return !btf_type_is_modifier(next_type) &&
1826 !btf_type_is_array(next_type) &&
1827 !btf_type_is_struct(next_type);
1828 default:
1829 BUG();
1830 }
1831}
1832
1833static bool env_type_is_resolved(const struct btf_verifier_env *env,
1834 u32 type_id)
1835{
1836 /* base BTF types should be resolved by now */
1837 if (type_id < env->btf->start_id)
1838 return true;
1839
1840 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1841}
1842
1843static int env_stack_push(struct btf_verifier_env *env,
1844 const struct btf_type *t, u32 type_id)
1845{
1846 const struct btf *btf = env->btf;
1847 struct resolve_vertex *v;
1848
1849 if (env->top_stack == MAX_RESOLVE_DEPTH)
1850 return -E2BIG;
1851
1852 if (type_id < btf->start_id
1853 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1854 return -EEXIST;
1855
1856 env->visit_states[type_id - btf->start_id] = VISITED;
1857
1858 v = &env->stack[env->top_stack++];
1859 v->t = t;
1860 v->type_id = type_id;
1861 v->next_member = 0;
1862
1863 if (env->resolve_mode == RESOLVE_TBD) {
1864 if (btf_type_is_ptr(t))
1865 env->resolve_mode = RESOLVE_PTR;
1866 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1867 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1868 }
1869
1870 return 0;
1871}
1872
1873static void env_stack_set_next_member(struct btf_verifier_env *env,
1874 u16 next_member)
1875{
1876 env->stack[env->top_stack - 1].next_member = next_member;
1877}
1878
1879static void env_stack_pop_resolved(struct btf_verifier_env *env,
1880 u32 resolved_type_id,
1881 u32 resolved_size)
1882{
1883 u32 type_id = env->stack[--(env->top_stack)].type_id;
1884 struct btf *btf = env->btf;
1885
1886 type_id -= btf->start_id; /* adjust to local type id */
1887 btf->resolved_sizes[type_id] = resolved_size;
1888 btf->resolved_ids[type_id] = resolved_type_id;
1889 env->visit_states[type_id] = RESOLVED;
1890}
1891
1892static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1893{
1894 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1895}
1896
1897/* Resolve the size of a passed-in "type"
1898 *
1899 * type: is an array (e.g. u32 array[x][y])
1900 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1901 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1902 * corresponds to the return type.
1903 * *elem_type: u32
1904 * *elem_id: id of u32
1905 * *total_nelems: (x * y). Hence, individual elem size is
1906 * (*type_size / *total_nelems)
1907 * *type_id: id of type if it's changed within the function, 0 if not
1908 *
1909 * type: is not an array (e.g. const struct X)
1910 * return type: type "struct X"
1911 * *type_size: sizeof(struct X)
1912 * *elem_type: same as return type ("struct X")
1913 * *elem_id: 0
1914 * *total_nelems: 1
1915 * *type_id: id of type if it's changed within the function, 0 if not
1916 */
1917static const struct btf_type *
1918__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1919 u32 *type_size, const struct btf_type **elem_type,
1920 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1921{
1922 const struct btf_type *array_type = NULL;
1923 const struct btf_array *array = NULL;
1924 u32 i, size, nelems = 1, id = 0;
1925
1926 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1927 switch (BTF_INFO_KIND(type->info)) {
1928 /* type->size can be used */
1929 case BTF_KIND_INT:
1930 case BTF_KIND_STRUCT:
1931 case BTF_KIND_UNION:
1932 case BTF_KIND_ENUM:
1933 case BTF_KIND_FLOAT:
1934 case BTF_KIND_ENUM64:
1935 size = type->size;
1936 goto resolved;
1937
1938 case BTF_KIND_PTR:
1939 size = sizeof(void *);
1940 goto resolved;
1941
1942 /* Modifiers */
1943 case BTF_KIND_TYPEDEF:
1944 case BTF_KIND_VOLATILE:
1945 case BTF_KIND_CONST:
1946 case BTF_KIND_RESTRICT:
1947 case BTF_KIND_TYPE_TAG:
1948 id = type->type;
1949 type = btf_type_by_id(btf, type->type);
1950 break;
1951
1952 case BTF_KIND_ARRAY:
1953 if (!array_type)
1954 array_type = type;
1955 array = btf_type_array(type);
1956 if (nelems && array->nelems > U32_MAX / nelems)
1957 return ERR_PTR(-EINVAL);
1958 nelems *= array->nelems;
1959 type = btf_type_by_id(btf, array->type);
1960 break;
1961
1962 /* type without size */
1963 default:
1964 return ERR_PTR(-EINVAL);
1965 }
1966 }
1967
1968 return ERR_PTR(-EINVAL);
1969
1970resolved:
1971 if (nelems && size > U32_MAX / nelems)
1972 return ERR_PTR(-EINVAL);
1973
1974 *type_size = nelems * size;
1975 if (total_nelems)
1976 *total_nelems = nelems;
1977 if (elem_type)
1978 *elem_type = type;
1979 if (elem_id)
1980 *elem_id = array ? array->type : 0;
1981 if (type_id && id)
1982 *type_id = id;
1983
1984 return array_type ? : type;
1985}
1986
1987const struct btf_type *
1988btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1989 u32 *type_size)
1990{
1991 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1992}
1993
1994static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1995{
1996 while (type_id < btf->start_id)
1997 btf = btf->base_btf;
1998
1999 return btf->resolved_ids[type_id - btf->start_id];
2000}
2001
2002/* The input param "type_id" must point to a needs_resolve type */
2003static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
2004 u32 *type_id)
2005{
2006 *type_id = btf_resolved_type_id(btf, *type_id);
2007 return btf_type_by_id(btf, *type_id);
2008}
2009
2010static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
2011{
2012 while (type_id < btf->start_id)
2013 btf = btf->base_btf;
2014
2015 return btf->resolved_sizes[type_id - btf->start_id];
2016}
2017
2018const struct btf_type *btf_type_id_size(const struct btf *btf,
2019 u32 *type_id, u32 *ret_size)
2020{
2021 const struct btf_type *size_type;
2022 u32 size_type_id = *type_id;
2023 u32 size = 0;
2024
2025 size_type = btf_type_by_id(btf, size_type_id);
2026 if (btf_type_nosize_or_null(size_type))
2027 return NULL;
2028
2029 if (btf_type_has_size(size_type)) {
2030 size = size_type->size;
2031 } else if (btf_type_is_array(size_type)) {
2032 size = btf_resolved_type_size(btf, size_type_id);
2033 } else if (btf_type_is_ptr(size_type)) {
2034 size = sizeof(void *);
2035 } else {
2036 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
2037 !btf_type_is_var(size_type)))
2038 return NULL;
2039
2040 size_type_id = btf_resolved_type_id(btf, size_type_id);
2041 size_type = btf_type_by_id(btf, size_type_id);
2042 if (btf_type_nosize_or_null(size_type))
2043 return NULL;
2044 else if (btf_type_has_size(size_type))
2045 size = size_type->size;
2046 else if (btf_type_is_array(size_type))
2047 size = btf_resolved_type_size(btf, size_type_id);
2048 else if (btf_type_is_ptr(size_type))
2049 size = sizeof(void *);
2050 else
2051 return NULL;
2052 }
2053
2054 *type_id = size_type_id;
2055 if (ret_size)
2056 *ret_size = size;
2057
2058 return size_type;
2059}
2060
2061static int btf_df_check_member(struct btf_verifier_env *env,
2062 const struct btf_type *struct_type,
2063 const struct btf_member *member,
2064 const struct btf_type *member_type)
2065{
2066 btf_verifier_log_basic(env, struct_type,
2067 "Unsupported check_member");
2068 return -EINVAL;
2069}
2070
2071static int btf_df_check_kflag_member(struct btf_verifier_env *env,
2072 const struct btf_type *struct_type,
2073 const struct btf_member *member,
2074 const struct btf_type *member_type)
2075{
2076 btf_verifier_log_basic(env, struct_type,
2077 "Unsupported check_kflag_member");
2078 return -EINVAL;
2079}
2080
2081/* Used for ptr, array struct/union and float type members.
2082 * int, enum and modifier types have their specific callback functions.
2083 */
2084static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
2085 const struct btf_type *struct_type,
2086 const struct btf_member *member,
2087 const struct btf_type *member_type)
2088{
2089 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2090 btf_verifier_log_member(env, struct_type, member,
2091 "Invalid member bitfield_size");
2092 return -EINVAL;
2093 }
2094
2095 /* bitfield size is 0, so member->offset represents bit offset only.
2096 * It is safe to call non kflag check_member variants.
2097 */
2098 return btf_type_ops(member_type)->check_member(env, struct_type,
2099 member,
2100 member_type);
2101}
2102
2103static int btf_df_resolve(struct btf_verifier_env *env,
2104 const struct resolve_vertex *v)
2105{
2106 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2107 return -EINVAL;
2108}
2109
2110static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2111 u32 type_id, void *data, u8 bits_offsets,
2112 struct btf_show *show)
2113{
2114 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2115}
2116
2117static int btf_int_check_member(struct btf_verifier_env *env,
2118 const struct btf_type *struct_type,
2119 const struct btf_member *member,
2120 const struct btf_type *member_type)
2121{
2122 u32 int_data = btf_type_int(member_type);
2123 u32 struct_bits_off = member->offset;
2124 u32 struct_size = struct_type->size;
2125 u32 nr_copy_bits;
2126 u32 bytes_offset;
2127
2128 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2129 btf_verifier_log_member(env, struct_type, member,
2130 "bits_offset exceeds U32_MAX");
2131 return -EINVAL;
2132 }
2133
2134 struct_bits_off += BTF_INT_OFFSET(int_data);
2135 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2136 nr_copy_bits = BTF_INT_BITS(int_data) +
2137 BITS_PER_BYTE_MASKED(struct_bits_off);
2138
2139 if (nr_copy_bits > BITS_PER_U128) {
2140 btf_verifier_log_member(env, struct_type, member,
2141 "nr_copy_bits exceeds 128");
2142 return -EINVAL;
2143 }
2144
2145 if (struct_size < bytes_offset ||
2146 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2147 btf_verifier_log_member(env, struct_type, member,
2148 "Member exceeds struct_size");
2149 return -EINVAL;
2150 }
2151
2152 return 0;
2153}
2154
2155static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2156 const struct btf_type *struct_type,
2157 const struct btf_member *member,
2158 const struct btf_type *member_type)
2159{
2160 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2161 u32 int_data = btf_type_int(member_type);
2162 u32 struct_size = struct_type->size;
2163 u32 nr_copy_bits;
2164
2165 /* a regular int type is required for the kflag int member */
2166 if (!btf_type_int_is_regular(member_type)) {
2167 btf_verifier_log_member(env, struct_type, member,
2168 "Invalid member base type");
2169 return -EINVAL;
2170 }
2171
2172 /* check sanity of bitfield size */
2173 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2174 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2175 nr_int_data_bits = BTF_INT_BITS(int_data);
2176 if (!nr_bits) {
2177 /* Not a bitfield member, member offset must be at byte
2178 * boundary.
2179 */
2180 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2181 btf_verifier_log_member(env, struct_type, member,
2182 "Invalid member offset");
2183 return -EINVAL;
2184 }
2185
2186 nr_bits = nr_int_data_bits;
2187 } else if (nr_bits > nr_int_data_bits) {
2188 btf_verifier_log_member(env, struct_type, member,
2189 "Invalid member bitfield_size");
2190 return -EINVAL;
2191 }
2192
2193 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2194 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2195 if (nr_copy_bits > BITS_PER_U128) {
2196 btf_verifier_log_member(env, struct_type, member,
2197 "nr_copy_bits exceeds 128");
2198 return -EINVAL;
2199 }
2200
2201 if (struct_size < bytes_offset ||
2202 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2203 btf_verifier_log_member(env, struct_type, member,
2204 "Member exceeds struct_size");
2205 return -EINVAL;
2206 }
2207
2208 return 0;
2209}
2210
2211static s32 btf_int_check_meta(struct btf_verifier_env *env,
2212 const struct btf_type *t,
2213 u32 meta_left)
2214{
2215 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2216 u16 encoding;
2217
2218 if (meta_left < meta_needed) {
2219 btf_verifier_log_basic(env, t,
2220 "meta_left:%u meta_needed:%u",
2221 meta_left, meta_needed);
2222 return -EINVAL;
2223 }
2224
2225 if (btf_type_vlen(t)) {
2226 btf_verifier_log_type(env, t, "vlen != 0");
2227 return -EINVAL;
2228 }
2229
2230 if (btf_type_kflag(t)) {
2231 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2232 return -EINVAL;
2233 }
2234
2235 int_data = btf_type_int(t);
2236 if (int_data & ~BTF_INT_MASK) {
2237 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2238 int_data);
2239 return -EINVAL;
2240 }
2241
2242 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2243
2244 if (nr_bits > BITS_PER_U128) {
2245 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2246 BITS_PER_U128);
2247 return -EINVAL;
2248 }
2249
2250 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2251 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2252 return -EINVAL;
2253 }
2254
2255 /*
2256 * Only one of the encoding bits is allowed and it
2257 * should be sufficient for the pretty print purpose (i.e. decoding).
2258 * Multiple bits can be allowed later if it is found
2259 * to be insufficient.
2260 */
2261 encoding = BTF_INT_ENCODING(int_data);
2262 if (encoding &&
2263 encoding != BTF_INT_SIGNED &&
2264 encoding != BTF_INT_CHAR &&
2265 encoding != BTF_INT_BOOL) {
2266 btf_verifier_log_type(env, t, "Unsupported encoding");
2267 return -ENOTSUPP;
2268 }
2269
2270 btf_verifier_log_type(env, t, NULL);
2271
2272 return meta_needed;
2273}
2274
2275static void btf_int_log(struct btf_verifier_env *env,
2276 const struct btf_type *t)
2277{
2278 int int_data = btf_type_int(t);
2279
2280 btf_verifier_log(env,
2281 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2282 t->size, BTF_INT_OFFSET(int_data),
2283 BTF_INT_BITS(int_data),
2284 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2285}
2286
2287static void btf_int128_print(struct btf_show *show, void *data)
2288{
2289 /* data points to a __int128 number.
2290 * Suppose
2291 * int128_num = *(__int128 *)data;
2292 * The below formulas shows what upper_num and lower_num represents:
2293 * upper_num = int128_num >> 64;
2294 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2295 */
2296 u64 upper_num, lower_num;
2297
2298#ifdef __BIG_ENDIAN_BITFIELD
2299 upper_num = *(u64 *)data;
2300 lower_num = *(u64 *)(data + 8);
2301#else
2302 upper_num = *(u64 *)(data + 8);
2303 lower_num = *(u64 *)data;
2304#endif
2305 if (upper_num == 0)
2306 btf_show_type_value(show, "0x%llx", lower_num);
2307 else
2308 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2309 lower_num);
2310}
2311
2312static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2313 u16 right_shift_bits)
2314{
2315 u64 upper_num, lower_num;
2316
2317#ifdef __BIG_ENDIAN_BITFIELD
2318 upper_num = print_num[0];
2319 lower_num = print_num[1];
2320#else
2321 upper_num = print_num[1];
2322 lower_num = print_num[0];
2323#endif
2324
2325 /* shake out un-needed bits by shift/or operations */
2326 if (left_shift_bits >= 64) {
2327 upper_num = lower_num << (left_shift_bits - 64);
2328 lower_num = 0;
2329 } else {
2330 upper_num = (upper_num << left_shift_bits) |
2331 (lower_num >> (64 - left_shift_bits));
2332 lower_num = lower_num << left_shift_bits;
2333 }
2334
2335 if (right_shift_bits >= 64) {
2336 lower_num = upper_num >> (right_shift_bits - 64);
2337 upper_num = 0;
2338 } else {
2339 lower_num = (lower_num >> right_shift_bits) |
2340 (upper_num << (64 - right_shift_bits));
2341 upper_num = upper_num >> right_shift_bits;
2342 }
2343
2344#ifdef __BIG_ENDIAN_BITFIELD
2345 print_num[0] = upper_num;
2346 print_num[1] = lower_num;
2347#else
2348 print_num[0] = lower_num;
2349 print_num[1] = upper_num;
2350#endif
2351}
2352
2353static void btf_bitfield_show(void *data, u8 bits_offset,
2354 u8 nr_bits, struct btf_show *show)
2355{
2356 u16 left_shift_bits, right_shift_bits;
2357 u8 nr_copy_bytes;
2358 u8 nr_copy_bits;
2359 u64 print_num[2] = {};
2360
2361 nr_copy_bits = nr_bits + bits_offset;
2362 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2363
2364 memcpy(print_num, data, nr_copy_bytes);
2365
2366#ifdef __BIG_ENDIAN_BITFIELD
2367 left_shift_bits = bits_offset;
2368#else
2369 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2370#endif
2371 right_shift_bits = BITS_PER_U128 - nr_bits;
2372
2373 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2374 btf_int128_print(show, print_num);
2375}
2376
2377
2378static void btf_int_bits_show(const struct btf *btf,
2379 const struct btf_type *t,
2380 void *data, u8 bits_offset,
2381 struct btf_show *show)
2382{
2383 u32 int_data = btf_type_int(t);
2384 u8 nr_bits = BTF_INT_BITS(int_data);
2385 u8 total_bits_offset;
2386
2387 /*
2388 * bits_offset is at most 7.
2389 * BTF_INT_OFFSET() cannot exceed 128 bits.
2390 */
2391 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2392 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2393 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2394 btf_bitfield_show(data, bits_offset, nr_bits, show);
2395}
2396
2397static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2398 u32 type_id, void *data, u8 bits_offset,
2399 struct btf_show *show)
2400{
2401 u32 int_data = btf_type_int(t);
2402 u8 encoding = BTF_INT_ENCODING(int_data);
2403 bool sign = encoding & BTF_INT_SIGNED;
2404 u8 nr_bits = BTF_INT_BITS(int_data);
2405 void *safe_data;
2406
2407 safe_data = btf_show_start_type(show, t, type_id, data);
2408 if (!safe_data)
2409 return;
2410
2411 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2412 BITS_PER_BYTE_MASKED(nr_bits)) {
2413 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2414 goto out;
2415 }
2416
2417 switch (nr_bits) {
2418 case 128:
2419 btf_int128_print(show, safe_data);
2420 break;
2421 case 64:
2422 if (sign)
2423 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2424 else
2425 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2426 break;
2427 case 32:
2428 if (sign)
2429 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2430 else
2431 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2432 break;
2433 case 16:
2434 if (sign)
2435 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2436 else
2437 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2438 break;
2439 case 8:
2440 if (show->state.array_encoding == BTF_INT_CHAR) {
2441 /* check for null terminator */
2442 if (show->state.array_terminated)
2443 break;
2444 if (*(char *)data == '\0') {
2445 show->state.array_terminated = 1;
2446 break;
2447 }
2448 if (isprint(*(char *)data)) {
2449 btf_show_type_value(show, "'%c'",
2450 *(char *)safe_data);
2451 break;
2452 }
2453 }
2454 if (sign)
2455 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2456 else
2457 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2458 break;
2459 default:
2460 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2461 break;
2462 }
2463out:
2464 btf_show_end_type(show);
2465}
2466
2467static const struct btf_kind_operations int_ops = {
2468 .check_meta = btf_int_check_meta,
2469 .resolve = btf_df_resolve,
2470 .check_member = btf_int_check_member,
2471 .check_kflag_member = btf_int_check_kflag_member,
2472 .log_details = btf_int_log,
2473 .show = btf_int_show,
2474};
2475
2476static int btf_modifier_check_member(struct btf_verifier_env *env,
2477 const struct btf_type *struct_type,
2478 const struct btf_member *member,
2479 const struct btf_type *member_type)
2480{
2481 const struct btf_type *resolved_type;
2482 u32 resolved_type_id = member->type;
2483 struct btf_member resolved_member;
2484 struct btf *btf = env->btf;
2485
2486 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2487 if (!resolved_type) {
2488 btf_verifier_log_member(env, struct_type, member,
2489 "Invalid member");
2490 return -EINVAL;
2491 }
2492
2493 resolved_member = *member;
2494 resolved_member.type = resolved_type_id;
2495
2496 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2497 &resolved_member,
2498 resolved_type);
2499}
2500
2501static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2502 const struct btf_type *struct_type,
2503 const struct btf_member *member,
2504 const struct btf_type *member_type)
2505{
2506 const struct btf_type *resolved_type;
2507 u32 resolved_type_id = member->type;
2508 struct btf_member resolved_member;
2509 struct btf *btf = env->btf;
2510
2511 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2512 if (!resolved_type) {
2513 btf_verifier_log_member(env, struct_type, member,
2514 "Invalid member");
2515 return -EINVAL;
2516 }
2517
2518 resolved_member = *member;
2519 resolved_member.type = resolved_type_id;
2520
2521 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2522 &resolved_member,
2523 resolved_type);
2524}
2525
2526static int btf_ptr_check_member(struct btf_verifier_env *env,
2527 const struct btf_type *struct_type,
2528 const struct btf_member *member,
2529 const struct btf_type *member_type)
2530{
2531 u32 struct_size, struct_bits_off, bytes_offset;
2532
2533 struct_size = struct_type->size;
2534 struct_bits_off = member->offset;
2535 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2536
2537 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2538 btf_verifier_log_member(env, struct_type, member,
2539 "Member is not byte aligned");
2540 return -EINVAL;
2541 }
2542
2543 if (struct_size - bytes_offset < sizeof(void *)) {
2544 btf_verifier_log_member(env, struct_type, member,
2545 "Member exceeds struct_size");
2546 return -EINVAL;
2547 }
2548
2549 return 0;
2550}
2551
2552static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2553 const struct btf_type *t,
2554 u32 meta_left)
2555{
2556 const char *value;
2557
2558 if (btf_type_vlen(t)) {
2559 btf_verifier_log_type(env, t, "vlen != 0");
2560 return -EINVAL;
2561 }
2562
2563 if (btf_type_kflag(t)) {
2564 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2565 return -EINVAL;
2566 }
2567
2568 if (!BTF_TYPE_ID_VALID(t->type)) {
2569 btf_verifier_log_type(env, t, "Invalid type_id");
2570 return -EINVAL;
2571 }
2572
2573 /* typedef/type_tag type must have a valid name, and other ref types,
2574 * volatile, const, restrict, should have a null name.
2575 */
2576 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2577 if (!t->name_off ||
2578 !btf_name_valid_identifier(env->btf, t->name_off)) {
2579 btf_verifier_log_type(env, t, "Invalid name");
2580 return -EINVAL;
2581 }
2582 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2583 value = btf_name_by_offset(env->btf, t->name_off);
2584 if (!value || !value[0]) {
2585 btf_verifier_log_type(env, t, "Invalid name");
2586 return -EINVAL;
2587 }
2588 } else {
2589 if (t->name_off) {
2590 btf_verifier_log_type(env, t, "Invalid name");
2591 return -EINVAL;
2592 }
2593 }
2594
2595 btf_verifier_log_type(env, t, NULL);
2596
2597 return 0;
2598}
2599
2600static int btf_modifier_resolve(struct btf_verifier_env *env,
2601 const struct resolve_vertex *v)
2602{
2603 const struct btf_type *t = v->t;
2604 const struct btf_type *next_type;
2605 u32 next_type_id = t->type;
2606 struct btf *btf = env->btf;
2607
2608 next_type = btf_type_by_id(btf, next_type_id);
2609 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2610 btf_verifier_log_type(env, v->t, "Invalid type_id");
2611 return -EINVAL;
2612 }
2613
2614 if (!env_type_is_resolve_sink(env, next_type) &&
2615 !env_type_is_resolved(env, next_type_id))
2616 return env_stack_push(env, next_type, next_type_id);
2617
2618 /* Figure out the resolved next_type_id with size.
2619 * They will be stored in the current modifier's
2620 * resolved_ids and resolved_sizes such that it can
2621 * save us a few type-following when we use it later (e.g. in
2622 * pretty print).
2623 */
2624 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2625 if (env_type_is_resolved(env, next_type_id))
2626 next_type = btf_type_id_resolve(btf, &next_type_id);
2627
2628 /* "typedef void new_void", "const void"...etc */
2629 if (!btf_type_is_void(next_type) &&
2630 !btf_type_is_fwd(next_type) &&
2631 !btf_type_is_func_proto(next_type)) {
2632 btf_verifier_log_type(env, v->t, "Invalid type_id");
2633 return -EINVAL;
2634 }
2635 }
2636
2637 env_stack_pop_resolved(env, next_type_id, 0);
2638
2639 return 0;
2640}
2641
2642static int btf_var_resolve(struct btf_verifier_env *env,
2643 const struct resolve_vertex *v)
2644{
2645 const struct btf_type *next_type;
2646 const struct btf_type *t = v->t;
2647 u32 next_type_id = t->type;
2648 struct btf *btf = env->btf;
2649
2650 next_type = btf_type_by_id(btf, next_type_id);
2651 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2652 btf_verifier_log_type(env, v->t, "Invalid type_id");
2653 return -EINVAL;
2654 }
2655
2656 if (!env_type_is_resolve_sink(env, next_type) &&
2657 !env_type_is_resolved(env, next_type_id))
2658 return env_stack_push(env, next_type, next_type_id);
2659
2660 if (btf_type_is_modifier(next_type)) {
2661 const struct btf_type *resolved_type;
2662 u32 resolved_type_id;
2663
2664 resolved_type_id = next_type_id;
2665 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2666
2667 if (btf_type_is_ptr(resolved_type) &&
2668 !env_type_is_resolve_sink(env, resolved_type) &&
2669 !env_type_is_resolved(env, resolved_type_id))
2670 return env_stack_push(env, resolved_type,
2671 resolved_type_id);
2672 }
2673
2674 /* We must resolve to something concrete at this point, no
2675 * forward types or similar that would resolve to size of
2676 * zero is allowed.
2677 */
2678 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2679 btf_verifier_log_type(env, v->t, "Invalid type_id");
2680 return -EINVAL;
2681 }
2682
2683 env_stack_pop_resolved(env, next_type_id, 0);
2684
2685 return 0;
2686}
2687
2688static int btf_ptr_resolve(struct btf_verifier_env *env,
2689 const struct resolve_vertex *v)
2690{
2691 const struct btf_type *next_type;
2692 const struct btf_type *t = v->t;
2693 u32 next_type_id = t->type;
2694 struct btf *btf = env->btf;
2695
2696 next_type = btf_type_by_id(btf, next_type_id);
2697 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2698 btf_verifier_log_type(env, v->t, "Invalid type_id");
2699 return -EINVAL;
2700 }
2701
2702 if (!env_type_is_resolve_sink(env, next_type) &&
2703 !env_type_is_resolved(env, next_type_id))
2704 return env_stack_push(env, next_type, next_type_id);
2705
2706 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2707 * the modifier may have stopped resolving when it was resolved
2708 * to a ptr (last-resolved-ptr).
2709 *
2710 * We now need to continue from the last-resolved-ptr to
2711 * ensure the last-resolved-ptr will not referring back to
2712 * the current ptr (t).
2713 */
2714 if (btf_type_is_modifier(next_type)) {
2715 const struct btf_type *resolved_type;
2716 u32 resolved_type_id;
2717
2718 resolved_type_id = next_type_id;
2719 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2720
2721 if (btf_type_is_ptr(resolved_type) &&
2722 !env_type_is_resolve_sink(env, resolved_type) &&
2723 !env_type_is_resolved(env, resolved_type_id))
2724 return env_stack_push(env, resolved_type,
2725 resolved_type_id);
2726 }
2727
2728 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2729 if (env_type_is_resolved(env, next_type_id))
2730 next_type = btf_type_id_resolve(btf, &next_type_id);
2731
2732 if (!btf_type_is_void(next_type) &&
2733 !btf_type_is_fwd(next_type) &&
2734 !btf_type_is_func_proto(next_type)) {
2735 btf_verifier_log_type(env, v->t, "Invalid type_id");
2736 return -EINVAL;
2737 }
2738 }
2739
2740 env_stack_pop_resolved(env, next_type_id, 0);
2741
2742 return 0;
2743}
2744
2745static void btf_modifier_show(const struct btf *btf,
2746 const struct btf_type *t,
2747 u32 type_id, void *data,
2748 u8 bits_offset, struct btf_show *show)
2749{
2750 if (btf->resolved_ids)
2751 t = btf_type_id_resolve(btf, &type_id);
2752 else
2753 t = btf_type_skip_modifiers(btf, type_id, NULL);
2754
2755 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2756}
2757
2758static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2759 u32 type_id, void *data, u8 bits_offset,
2760 struct btf_show *show)
2761{
2762 t = btf_type_id_resolve(btf, &type_id);
2763
2764 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2765}
2766
2767static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2768 u32 type_id, void *data, u8 bits_offset,
2769 struct btf_show *show)
2770{
2771 void *safe_data;
2772
2773 safe_data = btf_show_start_type(show, t, type_id, data);
2774 if (!safe_data)
2775 return;
2776
2777 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2778 if (show->flags & BTF_SHOW_PTR_RAW)
2779 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2780 else
2781 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2782 btf_show_end_type(show);
2783}
2784
2785static void btf_ref_type_log(struct btf_verifier_env *env,
2786 const struct btf_type *t)
2787{
2788 btf_verifier_log(env, "type_id=%u", t->type);
2789}
2790
2791static struct btf_kind_operations modifier_ops = {
2792 .check_meta = btf_ref_type_check_meta,
2793 .resolve = btf_modifier_resolve,
2794 .check_member = btf_modifier_check_member,
2795 .check_kflag_member = btf_modifier_check_kflag_member,
2796 .log_details = btf_ref_type_log,
2797 .show = btf_modifier_show,
2798};
2799
2800static struct btf_kind_operations ptr_ops = {
2801 .check_meta = btf_ref_type_check_meta,
2802 .resolve = btf_ptr_resolve,
2803 .check_member = btf_ptr_check_member,
2804 .check_kflag_member = btf_generic_check_kflag_member,
2805 .log_details = btf_ref_type_log,
2806 .show = btf_ptr_show,
2807};
2808
2809static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2810 const struct btf_type *t,
2811 u32 meta_left)
2812{
2813 if (btf_type_vlen(t)) {
2814 btf_verifier_log_type(env, t, "vlen != 0");
2815 return -EINVAL;
2816 }
2817
2818 if (t->type) {
2819 btf_verifier_log_type(env, t, "type != 0");
2820 return -EINVAL;
2821 }
2822
2823 /* fwd type must have a valid name */
2824 if (!t->name_off ||
2825 !btf_name_valid_identifier(env->btf, t->name_off)) {
2826 btf_verifier_log_type(env, t, "Invalid name");
2827 return -EINVAL;
2828 }
2829
2830 btf_verifier_log_type(env, t, NULL);
2831
2832 return 0;
2833}
2834
2835static void btf_fwd_type_log(struct btf_verifier_env *env,
2836 const struct btf_type *t)
2837{
2838 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2839}
2840
2841static struct btf_kind_operations fwd_ops = {
2842 .check_meta = btf_fwd_check_meta,
2843 .resolve = btf_df_resolve,
2844 .check_member = btf_df_check_member,
2845 .check_kflag_member = btf_df_check_kflag_member,
2846 .log_details = btf_fwd_type_log,
2847 .show = btf_df_show,
2848};
2849
2850static int btf_array_check_member(struct btf_verifier_env *env,
2851 const struct btf_type *struct_type,
2852 const struct btf_member *member,
2853 const struct btf_type *member_type)
2854{
2855 u32 struct_bits_off = member->offset;
2856 u32 struct_size, bytes_offset;
2857 u32 array_type_id, array_size;
2858 struct btf *btf = env->btf;
2859
2860 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2861 btf_verifier_log_member(env, struct_type, member,
2862 "Member is not byte aligned");
2863 return -EINVAL;
2864 }
2865
2866 array_type_id = member->type;
2867 btf_type_id_size(btf, &array_type_id, &array_size);
2868 struct_size = struct_type->size;
2869 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2870 if (struct_size - bytes_offset < array_size) {
2871 btf_verifier_log_member(env, struct_type, member,
2872 "Member exceeds struct_size");
2873 return -EINVAL;
2874 }
2875
2876 return 0;
2877}
2878
2879static s32 btf_array_check_meta(struct btf_verifier_env *env,
2880 const struct btf_type *t,
2881 u32 meta_left)
2882{
2883 const struct btf_array *array = btf_type_array(t);
2884 u32 meta_needed = sizeof(*array);
2885
2886 if (meta_left < meta_needed) {
2887 btf_verifier_log_basic(env, t,
2888 "meta_left:%u meta_needed:%u",
2889 meta_left, meta_needed);
2890 return -EINVAL;
2891 }
2892
2893 /* array type should not have a name */
2894 if (t->name_off) {
2895 btf_verifier_log_type(env, t, "Invalid name");
2896 return -EINVAL;
2897 }
2898
2899 if (btf_type_vlen(t)) {
2900 btf_verifier_log_type(env, t, "vlen != 0");
2901 return -EINVAL;
2902 }
2903
2904 if (btf_type_kflag(t)) {
2905 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2906 return -EINVAL;
2907 }
2908
2909 if (t->size) {
2910 btf_verifier_log_type(env, t, "size != 0");
2911 return -EINVAL;
2912 }
2913
2914 /* Array elem type and index type cannot be in type void,
2915 * so !array->type and !array->index_type are not allowed.
2916 */
2917 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2918 btf_verifier_log_type(env, t, "Invalid elem");
2919 return -EINVAL;
2920 }
2921
2922 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2923 btf_verifier_log_type(env, t, "Invalid index");
2924 return -EINVAL;
2925 }
2926
2927 btf_verifier_log_type(env, t, NULL);
2928
2929 return meta_needed;
2930}
2931
2932static int btf_array_resolve(struct btf_verifier_env *env,
2933 const struct resolve_vertex *v)
2934{
2935 const struct btf_array *array = btf_type_array(v->t);
2936 const struct btf_type *elem_type, *index_type;
2937 u32 elem_type_id, index_type_id;
2938 struct btf *btf = env->btf;
2939 u32 elem_size;
2940
2941 /* Check array->index_type */
2942 index_type_id = array->index_type;
2943 index_type = btf_type_by_id(btf, index_type_id);
2944 if (btf_type_nosize_or_null(index_type) ||
2945 btf_type_is_resolve_source_only(index_type)) {
2946 btf_verifier_log_type(env, v->t, "Invalid index");
2947 return -EINVAL;
2948 }
2949
2950 if (!env_type_is_resolve_sink(env, index_type) &&
2951 !env_type_is_resolved(env, index_type_id))
2952 return env_stack_push(env, index_type, index_type_id);
2953
2954 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2955 if (!index_type || !btf_type_is_int(index_type) ||
2956 !btf_type_int_is_regular(index_type)) {
2957 btf_verifier_log_type(env, v->t, "Invalid index");
2958 return -EINVAL;
2959 }
2960
2961 /* Check array->type */
2962 elem_type_id = array->type;
2963 elem_type = btf_type_by_id(btf, elem_type_id);
2964 if (btf_type_nosize_or_null(elem_type) ||
2965 btf_type_is_resolve_source_only(elem_type)) {
2966 btf_verifier_log_type(env, v->t,
2967 "Invalid elem");
2968 return -EINVAL;
2969 }
2970
2971 if (!env_type_is_resolve_sink(env, elem_type) &&
2972 !env_type_is_resolved(env, elem_type_id))
2973 return env_stack_push(env, elem_type, elem_type_id);
2974
2975 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2976 if (!elem_type) {
2977 btf_verifier_log_type(env, v->t, "Invalid elem");
2978 return -EINVAL;
2979 }
2980
2981 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2982 btf_verifier_log_type(env, v->t, "Invalid array of int");
2983 return -EINVAL;
2984 }
2985
2986 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2987 btf_verifier_log_type(env, v->t,
2988 "Array size overflows U32_MAX");
2989 return -EINVAL;
2990 }
2991
2992 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2993
2994 return 0;
2995}
2996
2997static void btf_array_log(struct btf_verifier_env *env,
2998 const struct btf_type *t)
2999{
3000 const struct btf_array *array = btf_type_array(t);
3001
3002 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
3003 array->type, array->index_type, array->nelems);
3004}
3005
3006static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
3007 u32 type_id, void *data, u8 bits_offset,
3008 struct btf_show *show)
3009{
3010 const struct btf_array *array = btf_type_array(t);
3011 const struct btf_kind_operations *elem_ops;
3012 const struct btf_type *elem_type;
3013 u32 i, elem_size = 0, elem_type_id;
3014 u16 encoding = 0;
3015
3016 elem_type_id = array->type;
3017 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
3018 if (elem_type && btf_type_has_size(elem_type))
3019 elem_size = elem_type->size;
3020
3021 if (elem_type && btf_type_is_int(elem_type)) {
3022 u32 int_type = btf_type_int(elem_type);
3023
3024 encoding = BTF_INT_ENCODING(int_type);
3025
3026 /*
3027 * BTF_INT_CHAR encoding never seems to be set for
3028 * char arrays, so if size is 1 and element is
3029 * printable as a char, we'll do that.
3030 */
3031 if (elem_size == 1)
3032 encoding = BTF_INT_CHAR;
3033 }
3034
3035 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
3036 return;
3037
3038 if (!elem_type)
3039 goto out;
3040 elem_ops = btf_type_ops(elem_type);
3041
3042 for (i = 0; i < array->nelems; i++) {
3043
3044 btf_show_start_array_member(show);
3045
3046 elem_ops->show(btf, elem_type, elem_type_id, data,
3047 bits_offset, show);
3048 data += elem_size;
3049
3050 btf_show_end_array_member(show);
3051
3052 if (show->state.array_terminated)
3053 break;
3054 }
3055out:
3056 btf_show_end_array_type(show);
3057}
3058
3059static void btf_array_show(const struct btf *btf, const struct btf_type *t,
3060 u32 type_id, void *data, u8 bits_offset,
3061 struct btf_show *show)
3062{
3063 const struct btf_member *m = show->state.member;
3064
3065 /*
3066 * First check if any members would be shown (are non-zero).
3067 * See comments above "struct btf_show" definition for more
3068 * details on how this works at a high-level.
3069 */
3070 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3071 if (!show->state.depth_check) {
3072 show->state.depth_check = show->state.depth + 1;
3073 show->state.depth_to_show = 0;
3074 }
3075 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3076 show->state.member = m;
3077
3078 if (show->state.depth_check != show->state.depth + 1)
3079 return;
3080 show->state.depth_check = 0;
3081
3082 if (show->state.depth_to_show <= show->state.depth)
3083 return;
3084 /*
3085 * Reaching here indicates we have recursed and found
3086 * non-zero array member(s).
3087 */
3088 }
3089 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3090}
3091
3092static struct btf_kind_operations array_ops = {
3093 .check_meta = btf_array_check_meta,
3094 .resolve = btf_array_resolve,
3095 .check_member = btf_array_check_member,
3096 .check_kflag_member = btf_generic_check_kflag_member,
3097 .log_details = btf_array_log,
3098 .show = btf_array_show,
3099};
3100
3101static int btf_struct_check_member(struct btf_verifier_env *env,
3102 const struct btf_type *struct_type,
3103 const struct btf_member *member,
3104 const struct btf_type *member_type)
3105{
3106 u32 struct_bits_off = member->offset;
3107 u32 struct_size, bytes_offset;
3108
3109 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3110 btf_verifier_log_member(env, struct_type, member,
3111 "Member is not byte aligned");
3112 return -EINVAL;
3113 }
3114
3115 struct_size = struct_type->size;
3116 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3117 if (struct_size - bytes_offset < member_type->size) {
3118 btf_verifier_log_member(env, struct_type, member,
3119 "Member exceeds struct_size");
3120 return -EINVAL;
3121 }
3122
3123 return 0;
3124}
3125
3126static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3127 const struct btf_type *t,
3128 u32 meta_left)
3129{
3130 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3131 const struct btf_member *member;
3132 u32 meta_needed, last_offset;
3133 struct btf *btf = env->btf;
3134 u32 struct_size = t->size;
3135 u32 offset;
3136 u16 i;
3137
3138 meta_needed = btf_type_vlen(t) * sizeof(*member);
3139 if (meta_left < meta_needed) {
3140 btf_verifier_log_basic(env, t,
3141 "meta_left:%u meta_needed:%u",
3142 meta_left, meta_needed);
3143 return -EINVAL;
3144 }
3145
3146 /* struct type either no name or a valid one */
3147 if (t->name_off &&
3148 !btf_name_valid_identifier(env->btf, t->name_off)) {
3149 btf_verifier_log_type(env, t, "Invalid name");
3150 return -EINVAL;
3151 }
3152
3153 btf_verifier_log_type(env, t, NULL);
3154
3155 last_offset = 0;
3156 for_each_member(i, t, member) {
3157 if (!btf_name_offset_valid(btf, member->name_off)) {
3158 btf_verifier_log_member(env, t, member,
3159 "Invalid member name_offset:%u",
3160 member->name_off);
3161 return -EINVAL;
3162 }
3163
3164 /* struct member either no name or a valid one */
3165 if (member->name_off &&
3166 !btf_name_valid_identifier(btf, member->name_off)) {
3167 btf_verifier_log_member(env, t, member, "Invalid name");
3168 return -EINVAL;
3169 }
3170 /* A member cannot be in type void */
3171 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3172 btf_verifier_log_member(env, t, member,
3173 "Invalid type_id");
3174 return -EINVAL;
3175 }
3176
3177 offset = __btf_member_bit_offset(t, member);
3178 if (is_union && offset) {
3179 btf_verifier_log_member(env, t, member,
3180 "Invalid member bits_offset");
3181 return -EINVAL;
3182 }
3183
3184 /*
3185 * ">" instead of ">=" because the last member could be
3186 * "char a[0];"
3187 */
3188 if (last_offset > offset) {
3189 btf_verifier_log_member(env, t, member,
3190 "Invalid member bits_offset");
3191 return -EINVAL;
3192 }
3193
3194 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3195 btf_verifier_log_member(env, t, member,
3196 "Member bits_offset exceeds its struct size");
3197 return -EINVAL;
3198 }
3199
3200 btf_verifier_log_member(env, t, member, NULL);
3201 last_offset = offset;
3202 }
3203
3204 return meta_needed;
3205}
3206
3207static int btf_struct_resolve(struct btf_verifier_env *env,
3208 const struct resolve_vertex *v)
3209{
3210 const struct btf_member *member;
3211 int err;
3212 u16 i;
3213
3214 /* Before continue resolving the next_member,
3215 * ensure the last member is indeed resolved to a
3216 * type with size info.
3217 */
3218 if (v->next_member) {
3219 const struct btf_type *last_member_type;
3220 const struct btf_member *last_member;
3221 u32 last_member_type_id;
3222
3223 last_member = btf_type_member(v->t) + v->next_member - 1;
3224 last_member_type_id = last_member->type;
3225 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3226 last_member_type_id)))
3227 return -EINVAL;
3228
3229 last_member_type = btf_type_by_id(env->btf,
3230 last_member_type_id);
3231 if (btf_type_kflag(v->t))
3232 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3233 last_member,
3234 last_member_type);
3235 else
3236 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3237 last_member,
3238 last_member_type);
3239 if (err)
3240 return err;
3241 }
3242
3243 for_each_member_from(i, v->next_member, v->t, member) {
3244 u32 member_type_id = member->type;
3245 const struct btf_type *member_type = btf_type_by_id(env->btf,
3246 member_type_id);
3247
3248 if (btf_type_nosize_or_null(member_type) ||
3249 btf_type_is_resolve_source_only(member_type)) {
3250 btf_verifier_log_member(env, v->t, member,
3251 "Invalid member");
3252 return -EINVAL;
3253 }
3254
3255 if (!env_type_is_resolve_sink(env, member_type) &&
3256 !env_type_is_resolved(env, member_type_id)) {
3257 env_stack_set_next_member(env, i + 1);
3258 return env_stack_push(env, member_type, member_type_id);
3259 }
3260
3261 if (btf_type_kflag(v->t))
3262 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3263 member,
3264 member_type);
3265 else
3266 err = btf_type_ops(member_type)->check_member(env, v->t,
3267 member,
3268 member_type);
3269 if (err)
3270 return err;
3271 }
3272
3273 env_stack_pop_resolved(env, 0, 0);
3274
3275 return 0;
3276}
3277
3278static void btf_struct_log(struct btf_verifier_env *env,
3279 const struct btf_type *t)
3280{
3281 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3282}
3283
3284enum {
3285 BTF_FIELD_IGNORE = 0,
3286 BTF_FIELD_FOUND = 1,
3287};
3288
3289struct btf_field_info {
3290 enum btf_field_type type;
3291 u32 off;
3292 union {
3293 struct {
3294 u32 type_id;
3295 } kptr;
3296 struct {
3297 const char *node_name;
3298 u32 value_btf_id;
3299 } graph_root;
3300 };
3301};
3302
3303static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3304 u32 off, int sz, enum btf_field_type field_type,
3305 struct btf_field_info *info)
3306{
3307 if (!__btf_type_is_struct(t))
3308 return BTF_FIELD_IGNORE;
3309 if (t->size != sz)
3310 return BTF_FIELD_IGNORE;
3311 info->type = field_type;
3312 info->off = off;
3313 return BTF_FIELD_FOUND;
3314}
3315
3316static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3317 u32 off, int sz, struct btf_field_info *info)
3318{
3319 enum btf_field_type type;
3320 u32 res_id;
3321
3322 /* Permit modifiers on the pointer itself */
3323 if (btf_type_is_volatile(t))
3324 t = btf_type_by_id(btf, t->type);
3325 /* For PTR, sz is always == 8 */
3326 if (!btf_type_is_ptr(t))
3327 return BTF_FIELD_IGNORE;
3328 t = btf_type_by_id(btf, t->type);
3329
3330 if (!btf_type_is_type_tag(t))
3331 return BTF_FIELD_IGNORE;
3332 /* Reject extra tags */
3333 if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3334 return -EINVAL;
3335 if (!strcmp("kptr_untrusted", __btf_name_by_offset(btf, t->name_off)))
3336 type = BPF_KPTR_UNREF;
3337 else if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3338 type = BPF_KPTR_REF;
3339 else if (!strcmp("percpu_kptr", __btf_name_by_offset(btf, t->name_off)))
3340 type = BPF_KPTR_PERCPU;
3341 else
3342 return -EINVAL;
3343
3344 /* Get the base type */
3345 t = btf_type_skip_modifiers(btf, t->type, &res_id);
3346 /* Only pointer to struct is allowed */
3347 if (!__btf_type_is_struct(t))
3348 return -EINVAL;
3349
3350 info->type = type;
3351 info->off = off;
3352 info->kptr.type_id = res_id;
3353 return BTF_FIELD_FOUND;
3354}
3355
3356int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt,
3357 int comp_idx, const char *tag_key, int last_id)
3358{
3359 int len = strlen(tag_key);
3360 int i, n;
3361
3362 for (i = last_id + 1, n = btf_nr_types(btf); i < n; i++) {
3363 const struct btf_type *t = btf_type_by_id(btf, i);
3364
3365 if (!btf_type_is_decl_tag(t))
3366 continue;
3367 if (pt != btf_type_by_id(btf, t->type))
3368 continue;
3369 if (btf_type_decl_tag(t)->component_idx != comp_idx)
3370 continue;
3371 if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
3372 continue;
3373 return i;
3374 }
3375 return -ENOENT;
3376}
3377
3378const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
3379 int comp_idx, const char *tag_key)
3380{
3381 const char *value = NULL;
3382 const struct btf_type *t;
3383 int len, id;
3384
3385 id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, 0);
3386 if (id < 0)
3387 return ERR_PTR(id);
3388
3389 t = btf_type_by_id(btf, id);
3390 len = strlen(tag_key);
3391 value = __btf_name_by_offset(btf, t->name_off) + len;
3392
3393 /* Prevent duplicate entries for same type */
3394 id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, id);
3395 if (id >= 0)
3396 return ERR_PTR(-EEXIST);
3397
3398 return value;
3399}
3400
3401static int
3402btf_find_graph_root(const struct btf *btf, const struct btf_type *pt,
3403 const struct btf_type *t, int comp_idx, u32 off,
3404 int sz, struct btf_field_info *info,
3405 enum btf_field_type head_type)
3406{
3407 const char *node_field_name;
3408 const char *value_type;
3409 s32 id;
3410
3411 if (!__btf_type_is_struct(t))
3412 return BTF_FIELD_IGNORE;
3413 if (t->size != sz)
3414 return BTF_FIELD_IGNORE;
3415 value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
3416 if (IS_ERR(value_type))
3417 return -EINVAL;
3418 node_field_name = strstr(value_type, ":");
3419 if (!node_field_name)
3420 return -EINVAL;
3421 value_type = kstrndup(value_type, node_field_name - value_type, GFP_KERNEL | __GFP_NOWARN);
3422 if (!value_type)
3423 return -ENOMEM;
3424 id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
3425 kfree(value_type);
3426 if (id < 0)
3427 return id;
3428 node_field_name++;
3429 if (str_is_empty(node_field_name))
3430 return -EINVAL;
3431 info->type = head_type;
3432 info->off = off;
3433 info->graph_root.value_btf_id = id;
3434 info->graph_root.node_name = node_field_name;
3435 return BTF_FIELD_FOUND;
3436}
3437
3438#define field_mask_test_name(field_type, field_type_str) \
3439 if (field_mask & field_type && !strcmp(name, field_type_str)) { \
3440 type = field_type; \
3441 goto end; \
3442 }
3443
3444static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask,
3445 int *align, int *sz)
3446{
3447 int type = 0;
3448
3449 if (field_mask & BPF_SPIN_LOCK) {
3450 if (!strcmp(name, "bpf_spin_lock")) {
3451 if (*seen_mask & BPF_SPIN_LOCK)
3452 return -E2BIG;
3453 *seen_mask |= BPF_SPIN_LOCK;
3454 type = BPF_SPIN_LOCK;
3455 goto end;
3456 }
3457 }
3458 if (field_mask & BPF_TIMER) {
3459 if (!strcmp(name, "bpf_timer")) {
3460 if (*seen_mask & BPF_TIMER)
3461 return -E2BIG;
3462 *seen_mask |= BPF_TIMER;
3463 type = BPF_TIMER;
3464 goto end;
3465 }
3466 }
3467 field_mask_test_name(BPF_LIST_HEAD, "bpf_list_head");
3468 field_mask_test_name(BPF_LIST_NODE, "bpf_list_node");
3469 field_mask_test_name(BPF_RB_ROOT, "bpf_rb_root");
3470 field_mask_test_name(BPF_RB_NODE, "bpf_rb_node");
3471 field_mask_test_name(BPF_REFCOUNT, "bpf_refcount");
3472
3473 /* Only return BPF_KPTR when all other types with matchable names fail */
3474 if (field_mask & BPF_KPTR) {
3475 type = BPF_KPTR_REF;
3476 goto end;
3477 }
3478 return 0;
3479end:
3480 *sz = btf_field_type_size(type);
3481 *align = btf_field_type_align(type);
3482 return type;
3483}
3484
3485#undef field_mask_test_name
3486
3487static int btf_find_struct_field(const struct btf *btf,
3488 const struct btf_type *t, u32 field_mask,
3489 struct btf_field_info *info, int info_cnt)
3490{
3491 int ret, idx = 0, align, sz, field_type;
3492 const struct btf_member *member;
3493 struct btf_field_info tmp;
3494 u32 i, off, seen_mask = 0;
3495
3496 for_each_member(i, t, member) {
3497 const struct btf_type *member_type = btf_type_by_id(btf,
3498 member->type);
3499
3500 field_type = btf_get_field_type(__btf_name_by_offset(btf, member_type->name_off),
3501 field_mask, &seen_mask, &align, &sz);
3502 if (field_type == 0)
3503 continue;
3504 if (field_type < 0)
3505 return field_type;
3506
3507 off = __btf_member_bit_offset(t, member);
3508 if (off % 8)
3509 /* valid C code cannot generate such BTF */
3510 return -EINVAL;
3511 off /= 8;
3512 if (off % align)
3513 continue;
3514
3515 switch (field_type) {
3516 case BPF_SPIN_LOCK:
3517 case BPF_TIMER:
3518 case BPF_LIST_NODE:
3519 case BPF_RB_NODE:
3520 case BPF_REFCOUNT:
3521 ret = btf_find_struct(btf, member_type, off, sz, field_type,
3522 idx < info_cnt ? &info[idx] : &tmp);
3523 if (ret < 0)
3524 return ret;
3525 break;
3526 case BPF_KPTR_UNREF:
3527 case BPF_KPTR_REF:
3528 case BPF_KPTR_PERCPU:
3529 ret = btf_find_kptr(btf, member_type, off, sz,
3530 idx < info_cnt ? &info[idx] : &tmp);
3531 if (ret < 0)
3532 return ret;
3533 break;
3534 case BPF_LIST_HEAD:
3535 case BPF_RB_ROOT:
3536 ret = btf_find_graph_root(btf, t, member_type,
3537 i, off, sz,
3538 idx < info_cnt ? &info[idx] : &tmp,
3539 field_type);
3540 if (ret < 0)
3541 return ret;
3542 break;
3543 default:
3544 return -EFAULT;
3545 }
3546
3547 if (ret == BTF_FIELD_IGNORE)
3548 continue;
3549 if (idx >= info_cnt)
3550 return -E2BIG;
3551 ++idx;
3552 }
3553 return idx;
3554}
3555
3556static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3557 u32 field_mask, struct btf_field_info *info,
3558 int info_cnt)
3559{
3560 int ret, idx = 0, align, sz, field_type;
3561 const struct btf_var_secinfo *vsi;
3562 struct btf_field_info tmp;
3563 u32 i, off, seen_mask = 0;
3564
3565 for_each_vsi(i, t, vsi) {
3566 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3567 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3568
3569 field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off),
3570 field_mask, &seen_mask, &align, &sz);
3571 if (field_type == 0)
3572 continue;
3573 if (field_type < 0)
3574 return field_type;
3575
3576 off = vsi->offset;
3577 if (vsi->size != sz)
3578 continue;
3579 if (off % align)
3580 continue;
3581
3582 switch (field_type) {
3583 case BPF_SPIN_LOCK:
3584 case BPF_TIMER:
3585 case BPF_LIST_NODE:
3586 case BPF_RB_NODE:
3587 case BPF_REFCOUNT:
3588 ret = btf_find_struct(btf, var_type, off, sz, field_type,
3589 idx < info_cnt ? &info[idx] : &tmp);
3590 if (ret < 0)
3591 return ret;
3592 break;
3593 case BPF_KPTR_UNREF:
3594 case BPF_KPTR_REF:
3595 case BPF_KPTR_PERCPU:
3596 ret = btf_find_kptr(btf, var_type, off, sz,
3597 idx < info_cnt ? &info[idx] : &tmp);
3598 if (ret < 0)
3599 return ret;
3600 break;
3601 case BPF_LIST_HEAD:
3602 case BPF_RB_ROOT:
3603 ret = btf_find_graph_root(btf, var, var_type,
3604 -1, off, sz,
3605 idx < info_cnt ? &info[idx] : &tmp,
3606 field_type);
3607 if (ret < 0)
3608 return ret;
3609 break;
3610 default:
3611 return -EFAULT;
3612 }
3613
3614 if (ret == BTF_FIELD_IGNORE)
3615 continue;
3616 if (idx >= info_cnt)
3617 return -E2BIG;
3618 ++idx;
3619 }
3620 return idx;
3621}
3622
3623static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3624 u32 field_mask, struct btf_field_info *info,
3625 int info_cnt)
3626{
3627 if (__btf_type_is_struct(t))
3628 return btf_find_struct_field(btf, t, field_mask, info, info_cnt);
3629 else if (btf_type_is_datasec(t))
3630 return btf_find_datasec_var(btf, t, field_mask, info, info_cnt);
3631 return -EINVAL;
3632}
3633
3634static int btf_parse_kptr(const struct btf *btf, struct btf_field *field,
3635 struct btf_field_info *info)
3636{
3637 struct module *mod = NULL;
3638 const struct btf_type *t;
3639 /* If a matching btf type is found in kernel or module BTFs, kptr_ref
3640 * is that BTF, otherwise it's program BTF
3641 */
3642 struct btf *kptr_btf;
3643 int ret;
3644 s32 id;
3645
3646 /* Find type in map BTF, and use it to look up the matching type
3647 * in vmlinux or module BTFs, by name and kind.
3648 */
3649 t = btf_type_by_id(btf, info->kptr.type_id);
3650 id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3651 &kptr_btf);
3652 if (id == -ENOENT) {
3653 /* btf_parse_kptr should only be called w/ btf = program BTF */
3654 WARN_ON_ONCE(btf_is_kernel(btf));
3655
3656 /* Type exists only in program BTF. Assume that it's a MEM_ALLOC
3657 * kptr allocated via bpf_obj_new
3658 */
3659 field->kptr.dtor = NULL;
3660 id = info->kptr.type_id;
3661 kptr_btf = (struct btf *)btf;
3662 btf_get(kptr_btf);
3663 goto found_dtor;
3664 }
3665 if (id < 0)
3666 return id;
3667
3668 /* Find and stash the function pointer for the destruction function that
3669 * needs to be eventually invoked from the map free path.
3670 */
3671 if (info->type == BPF_KPTR_REF) {
3672 const struct btf_type *dtor_func;
3673 const char *dtor_func_name;
3674 unsigned long addr;
3675 s32 dtor_btf_id;
3676
3677 /* This call also serves as a whitelist of allowed objects that
3678 * can be used as a referenced pointer and be stored in a map at
3679 * the same time.
3680 */
3681 dtor_btf_id = btf_find_dtor_kfunc(kptr_btf, id);
3682 if (dtor_btf_id < 0) {
3683 ret = dtor_btf_id;
3684 goto end_btf;
3685 }
3686
3687 dtor_func = btf_type_by_id(kptr_btf, dtor_btf_id);
3688 if (!dtor_func) {
3689 ret = -ENOENT;
3690 goto end_btf;
3691 }
3692
3693 if (btf_is_module(kptr_btf)) {
3694 mod = btf_try_get_module(kptr_btf);
3695 if (!mod) {
3696 ret = -ENXIO;
3697 goto end_btf;
3698 }
3699 }
3700
3701 /* We already verified dtor_func to be btf_type_is_func
3702 * in register_btf_id_dtor_kfuncs.
3703 */
3704 dtor_func_name = __btf_name_by_offset(kptr_btf, dtor_func->name_off);
3705 addr = kallsyms_lookup_name(dtor_func_name);
3706 if (!addr) {
3707 ret = -EINVAL;
3708 goto end_mod;
3709 }
3710 field->kptr.dtor = (void *)addr;
3711 }
3712
3713found_dtor:
3714 field->kptr.btf_id = id;
3715 field->kptr.btf = kptr_btf;
3716 field->kptr.module = mod;
3717 return 0;
3718end_mod:
3719 module_put(mod);
3720end_btf:
3721 btf_put(kptr_btf);
3722 return ret;
3723}
3724
3725static int btf_parse_graph_root(const struct btf *btf,
3726 struct btf_field *field,
3727 struct btf_field_info *info,
3728 const char *node_type_name,
3729 size_t node_type_align)
3730{
3731 const struct btf_type *t, *n = NULL;
3732 const struct btf_member *member;
3733 u32 offset;
3734 int i;
3735
3736 t = btf_type_by_id(btf, info->graph_root.value_btf_id);
3737 /* We've already checked that value_btf_id is a struct type. We
3738 * just need to figure out the offset of the list_node, and
3739 * verify its type.
3740 */
3741 for_each_member(i, t, member) {
3742 if (strcmp(info->graph_root.node_name,
3743 __btf_name_by_offset(btf, member->name_off)))
3744 continue;
3745 /* Invalid BTF, two members with same name */
3746 if (n)
3747 return -EINVAL;
3748 n = btf_type_by_id(btf, member->type);
3749 if (!__btf_type_is_struct(n))
3750 return -EINVAL;
3751 if (strcmp(node_type_name, __btf_name_by_offset(btf, n->name_off)))
3752 return -EINVAL;
3753 offset = __btf_member_bit_offset(n, member);
3754 if (offset % 8)
3755 return -EINVAL;
3756 offset /= 8;
3757 if (offset % node_type_align)
3758 return -EINVAL;
3759
3760 field->graph_root.btf = (struct btf *)btf;
3761 field->graph_root.value_btf_id = info->graph_root.value_btf_id;
3762 field->graph_root.node_offset = offset;
3763 }
3764 if (!n)
3765 return -ENOENT;
3766 return 0;
3767}
3768
3769static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
3770 struct btf_field_info *info)
3771{
3772 return btf_parse_graph_root(btf, field, info, "bpf_list_node",
3773 __alignof__(struct bpf_list_node));
3774}
3775
3776static int btf_parse_rb_root(const struct btf *btf, struct btf_field *field,
3777 struct btf_field_info *info)
3778{
3779 return btf_parse_graph_root(btf, field, info, "bpf_rb_node",
3780 __alignof__(struct bpf_rb_node));
3781}
3782
3783static int btf_field_cmp(const void *_a, const void *_b, const void *priv)
3784{
3785 const struct btf_field *a = (const struct btf_field *)_a;
3786 const struct btf_field *b = (const struct btf_field *)_b;
3787
3788 if (a->offset < b->offset)
3789 return -1;
3790 else if (a->offset > b->offset)
3791 return 1;
3792 return 0;
3793}
3794
3795struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
3796 u32 field_mask, u32 value_size)
3797{
3798 struct btf_field_info info_arr[BTF_FIELDS_MAX];
3799 u32 next_off = 0, field_type_size;
3800 struct btf_record *rec;
3801 int ret, i, cnt;
3802
3803 ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
3804 if (ret < 0)
3805 return ERR_PTR(ret);
3806 if (!ret)
3807 return NULL;
3808
3809 cnt = ret;
3810 /* This needs to be kzalloc to zero out padding and unused fields, see
3811 * comment in btf_record_equal.
3812 */
3813 rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);
3814 if (!rec)
3815 return ERR_PTR(-ENOMEM);
3816
3817 rec->spin_lock_off = -EINVAL;
3818 rec->timer_off = -EINVAL;
3819 rec->refcount_off = -EINVAL;
3820 for (i = 0; i < cnt; i++) {
3821 field_type_size = btf_field_type_size(info_arr[i].type);
3822 if (info_arr[i].off + field_type_size > value_size) {
3823 WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
3824 ret = -EFAULT;
3825 goto end;
3826 }
3827 if (info_arr[i].off < next_off) {
3828 ret = -EEXIST;
3829 goto end;
3830 }
3831 next_off = info_arr[i].off + field_type_size;
3832
3833 rec->field_mask |= info_arr[i].type;
3834 rec->fields[i].offset = info_arr[i].off;
3835 rec->fields[i].type = info_arr[i].type;
3836 rec->fields[i].size = field_type_size;
3837
3838 switch (info_arr[i].type) {
3839 case BPF_SPIN_LOCK:
3840 WARN_ON_ONCE(rec->spin_lock_off >= 0);
3841 /* Cache offset for faster lookup at runtime */
3842 rec->spin_lock_off = rec->fields[i].offset;
3843 break;
3844 case BPF_TIMER:
3845 WARN_ON_ONCE(rec->timer_off >= 0);
3846 /* Cache offset for faster lookup at runtime */
3847 rec->timer_off = rec->fields[i].offset;
3848 break;
3849 case BPF_REFCOUNT:
3850 WARN_ON_ONCE(rec->refcount_off >= 0);
3851 /* Cache offset for faster lookup at runtime */
3852 rec->refcount_off = rec->fields[i].offset;
3853 break;
3854 case BPF_KPTR_UNREF:
3855 case BPF_KPTR_REF:
3856 case BPF_KPTR_PERCPU:
3857 ret = btf_parse_kptr(btf, &rec->fields[i], &info_arr[i]);
3858 if (ret < 0)
3859 goto end;
3860 break;
3861 case BPF_LIST_HEAD:
3862 ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
3863 if (ret < 0)
3864 goto end;
3865 break;
3866 case BPF_RB_ROOT:
3867 ret = btf_parse_rb_root(btf, &rec->fields[i], &info_arr[i]);
3868 if (ret < 0)
3869 goto end;
3870 break;
3871 case BPF_LIST_NODE:
3872 case BPF_RB_NODE:
3873 break;
3874 default:
3875 ret = -EFAULT;
3876 goto end;
3877 }
3878 rec->cnt++;
3879 }
3880
3881 /* bpf_{list_head, rb_node} require bpf_spin_lock */
3882 if ((btf_record_has_field(rec, BPF_LIST_HEAD) ||
3883 btf_record_has_field(rec, BPF_RB_ROOT)) && rec->spin_lock_off < 0) {
3884 ret = -EINVAL;
3885 goto end;
3886 }
3887
3888 if (rec->refcount_off < 0 &&
3889 btf_record_has_field(rec, BPF_LIST_NODE) &&
3890 btf_record_has_field(rec, BPF_RB_NODE)) {
3891 ret = -EINVAL;
3892 goto end;
3893 }
3894
3895 sort_r(rec->fields, rec->cnt, sizeof(struct btf_field), btf_field_cmp,
3896 NULL, rec);
3897
3898 return rec;
3899end:
3900 btf_record_free(rec);
3901 return ERR_PTR(ret);
3902}
3903
3904int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
3905{
3906 int i;
3907
3908 /* There are three types that signify ownership of some other type:
3909 * kptr_ref, bpf_list_head, bpf_rb_root.
3910 * kptr_ref only supports storing kernel types, which can't store
3911 * references to program allocated local types.
3912 *
3913 * Hence we only need to ensure that bpf_{list_head,rb_root} ownership
3914 * does not form cycles.
3915 */
3916 if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & BPF_GRAPH_ROOT))
3917 return 0;
3918 for (i = 0; i < rec->cnt; i++) {
3919 struct btf_struct_meta *meta;
3920 u32 btf_id;
3921
3922 if (!(rec->fields[i].type & BPF_GRAPH_ROOT))
3923 continue;
3924 btf_id = rec->fields[i].graph_root.value_btf_id;
3925 meta = btf_find_struct_meta(btf, btf_id);
3926 if (!meta)
3927 return -EFAULT;
3928 rec->fields[i].graph_root.value_rec = meta->record;
3929
3930 /* We need to set value_rec for all root types, but no need
3931 * to check ownership cycle for a type unless it's also a
3932 * node type.
3933 */
3934 if (!(rec->field_mask & BPF_GRAPH_NODE))
3935 continue;
3936
3937 /* We need to ensure ownership acyclicity among all types. The
3938 * proper way to do it would be to topologically sort all BTF
3939 * IDs based on the ownership edges, since there can be multiple
3940 * bpf_{list_head,rb_node} in a type. Instead, we use the
3941 * following resaoning:
3942 *
3943 * - A type can only be owned by another type in user BTF if it
3944 * has a bpf_{list,rb}_node. Let's call these node types.
3945 * - A type can only _own_ another type in user BTF if it has a
3946 * bpf_{list_head,rb_root}. Let's call these root types.
3947 *
3948 * We ensure that if a type is both a root and node, its
3949 * element types cannot be root types.
3950 *
3951 * To ensure acyclicity:
3952 *
3953 * When A is an root type but not a node, its ownership
3954 * chain can be:
3955 * A -> B -> C
3956 * Where:
3957 * - A is an root, e.g. has bpf_rb_root.
3958 * - B is both a root and node, e.g. has bpf_rb_node and
3959 * bpf_list_head.
3960 * - C is only an root, e.g. has bpf_list_node
3961 *
3962 * When A is both a root and node, some other type already
3963 * owns it in the BTF domain, hence it can not own
3964 * another root type through any of the ownership edges.
3965 * A -> B
3966 * Where:
3967 * - A is both an root and node.
3968 * - B is only an node.
3969 */
3970 if (meta->record->field_mask & BPF_GRAPH_ROOT)
3971 return -ELOOP;
3972 }
3973 return 0;
3974}
3975
3976static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3977 u32 type_id, void *data, u8 bits_offset,
3978 struct btf_show *show)
3979{
3980 const struct btf_member *member;
3981 void *safe_data;
3982 u32 i;
3983
3984 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3985 if (!safe_data)
3986 return;
3987
3988 for_each_member(i, t, member) {
3989 const struct btf_type *member_type = btf_type_by_id(btf,
3990 member->type);
3991 const struct btf_kind_operations *ops;
3992 u32 member_offset, bitfield_size;
3993 u32 bytes_offset;
3994 u8 bits8_offset;
3995
3996 btf_show_start_member(show, member);
3997
3998 member_offset = __btf_member_bit_offset(t, member);
3999 bitfield_size = __btf_member_bitfield_size(t, member);
4000 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
4001 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
4002 if (bitfield_size) {
4003 safe_data = btf_show_start_type(show, member_type,
4004 member->type,
4005 data + bytes_offset);
4006 if (safe_data)
4007 btf_bitfield_show(safe_data,
4008 bits8_offset,
4009 bitfield_size, show);
4010 btf_show_end_type(show);
4011 } else {
4012 ops = btf_type_ops(member_type);
4013 ops->show(btf, member_type, member->type,
4014 data + bytes_offset, bits8_offset, show);
4015 }
4016
4017 btf_show_end_member(show);
4018 }
4019
4020 btf_show_end_struct_type(show);
4021}
4022
4023static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
4024 u32 type_id, void *data, u8 bits_offset,
4025 struct btf_show *show)
4026{
4027 const struct btf_member *m = show->state.member;
4028
4029 /*
4030 * First check if any members would be shown (are non-zero).
4031 * See comments above "struct btf_show" definition for more
4032 * details on how this works at a high-level.
4033 */
4034 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
4035 if (!show->state.depth_check) {
4036 show->state.depth_check = show->state.depth + 1;
4037 show->state.depth_to_show = 0;
4038 }
4039 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
4040 /* Restore saved member data here */
4041 show->state.member = m;
4042 if (show->state.depth_check != show->state.depth + 1)
4043 return;
4044 show->state.depth_check = 0;
4045
4046 if (show->state.depth_to_show <= show->state.depth)
4047 return;
4048 /*
4049 * Reaching here indicates we have recursed and found
4050 * non-zero child values.
4051 */
4052 }
4053
4054 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
4055}
4056
4057static struct btf_kind_operations struct_ops = {
4058 .check_meta = btf_struct_check_meta,
4059 .resolve = btf_struct_resolve,
4060 .check_member = btf_struct_check_member,
4061 .check_kflag_member = btf_generic_check_kflag_member,
4062 .log_details = btf_struct_log,
4063 .show = btf_struct_show,
4064};
4065
4066static int btf_enum_check_member(struct btf_verifier_env *env,
4067 const struct btf_type *struct_type,
4068 const struct btf_member *member,
4069 const struct btf_type *member_type)
4070{
4071 u32 struct_bits_off = member->offset;
4072 u32 struct_size, bytes_offset;
4073
4074 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4075 btf_verifier_log_member(env, struct_type, member,
4076 "Member is not byte aligned");
4077 return -EINVAL;
4078 }
4079
4080 struct_size = struct_type->size;
4081 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
4082 if (struct_size - bytes_offset < member_type->size) {
4083 btf_verifier_log_member(env, struct_type, member,
4084 "Member exceeds struct_size");
4085 return -EINVAL;
4086 }
4087
4088 return 0;
4089}
4090
4091static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
4092 const struct btf_type *struct_type,
4093 const struct btf_member *member,
4094 const struct btf_type *member_type)
4095{
4096 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
4097 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
4098
4099 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
4100 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
4101 if (!nr_bits) {
4102 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4103 btf_verifier_log_member(env, struct_type, member,
4104 "Member is not byte aligned");
4105 return -EINVAL;
4106 }
4107
4108 nr_bits = int_bitsize;
4109 } else if (nr_bits > int_bitsize) {
4110 btf_verifier_log_member(env, struct_type, member,
4111 "Invalid member bitfield_size");
4112 return -EINVAL;
4113 }
4114
4115 struct_size = struct_type->size;
4116 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
4117 if (struct_size < bytes_end) {
4118 btf_verifier_log_member(env, struct_type, member,
4119 "Member exceeds struct_size");
4120 return -EINVAL;
4121 }
4122
4123 return 0;
4124}
4125
4126static s32 btf_enum_check_meta(struct btf_verifier_env *env,
4127 const struct btf_type *t,
4128 u32 meta_left)
4129{
4130 const struct btf_enum *enums = btf_type_enum(t);
4131 struct btf *btf = env->btf;
4132 const char *fmt_str;
4133 u16 i, nr_enums;
4134 u32 meta_needed;
4135
4136 nr_enums = btf_type_vlen(t);
4137 meta_needed = nr_enums * sizeof(*enums);
4138
4139 if (meta_left < meta_needed) {
4140 btf_verifier_log_basic(env, t,
4141 "meta_left:%u meta_needed:%u",
4142 meta_left, meta_needed);
4143 return -EINVAL;
4144 }
4145
4146 if (t->size > 8 || !is_power_of_2(t->size)) {
4147 btf_verifier_log_type(env, t, "Unexpected size");
4148 return -EINVAL;
4149 }
4150
4151 /* enum type either no name or a valid one */
4152 if (t->name_off &&
4153 !btf_name_valid_identifier(env->btf, t->name_off)) {
4154 btf_verifier_log_type(env, t, "Invalid name");
4155 return -EINVAL;
4156 }
4157
4158 btf_verifier_log_type(env, t, NULL);
4159
4160 for (i = 0; i < nr_enums; i++) {
4161 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4162 btf_verifier_log(env, "\tInvalid name_offset:%u",
4163 enums[i].name_off);
4164 return -EINVAL;
4165 }
4166
4167 /* enum member must have a valid name */
4168 if (!enums[i].name_off ||
4169 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4170 btf_verifier_log_type(env, t, "Invalid name");
4171 return -EINVAL;
4172 }
4173
4174 if (env->log.level == BPF_LOG_KERNEL)
4175 continue;
4176 fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
4177 btf_verifier_log(env, fmt_str,
4178 __btf_name_by_offset(btf, enums[i].name_off),
4179 enums[i].val);
4180 }
4181
4182 return meta_needed;
4183}
4184
4185static void btf_enum_log(struct btf_verifier_env *env,
4186 const struct btf_type *t)
4187{
4188 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4189}
4190
4191static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
4192 u32 type_id, void *data, u8 bits_offset,
4193 struct btf_show *show)
4194{
4195 const struct btf_enum *enums = btf_type_enum(t);
4196 u32 i, nr_enums = btf_type_vlen(t);
4197 void *safe_data;
4198 int v;
4199
4200 safe_data = btf_show_start_type(show, t, type_id, data);
4201 if (!safe_data)
4202 return;
4203
4204 v = *(int *)safe_data;
4205
4206 for (i = 0; i < nr_enums; i++) {
4207 if (v != enums[i].val)
4208 continue;
4209
4210 btf_show_type_value(show, "%s",
4211 __btf_name_by_offset(btf,
4212 enums[i].name_off));
4213
4214 btf_show_end_type(show);
4215 return;
4216 }
4217
4218 if (btf_type_kflag(t))
4219 btf_show_type_value(show, "%d", v);
4220 else
4221 btf_show_type_value(show, "%u", v);
4222 btf_show_end_type(show);
4223}
4224
4225static struct btf_kind_operations enum_ops = {
4226 .check_meta = btf_enum_check_meta,
4227 .resolve = btf_df_resolve,
4228 .check_member = btf_enum_check_member,
4229 .check_kflag_member = btf_enum_check_kflag_member,
4230 .log_details = btf_enum_log,
4231 .show = btf_enum_show,
4232};
4233
4234static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
4235 const struct btf_type *t,
4236 u32 meta_left)
4237{
4238 const struct btf_enum64 *enums = btf_type_enum64(t);
4239 struct btf *btf = env->btf;
4240 const char *fmt_str;
4241 u16 i, nr_enums;
4242 u32 meta_needed;
4243
4244 nr_enums = btf_type_vlen(t);
4245 meta_needed = nr_enums * sizeof(*enums);
4246
4247 if (meta_left < meta_needed) {
4248 btf_verifier_log_basic(env, t,
4249 "meta_left:%u meta_needed:%u",
4250 meta_left, meta_needed);
4251 return -EINVAL;
4252 }
4253
4254 if (t->size > 8 || !is_power_of_2(t->size)) {
4255 btf_verifier_log_type(env, t, "Unexpected size");
4256 return -EINVAL;
4257 }
4258
4259 /* enum type either no name or a valid one */
4260 if (t->name_off &&
4261 !btf_name_valid_identifier(env->btf, t->name_off)) {
4262 btf_verifier_log_type(env, t, "Invalid name");
4263 return -EINVAL;
4264 }
4265
4266 btf_verifier_log_type(env, t, NULL);
4267
4268 for (i = 0; i < nr_enums; i++) {
4269 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4270 btf_verifier_log(env, "\tInvalid name_offset:%u",
4271 enums[i].name_off);
4272 return -EINVAL;
4273 }
4274
4275 /* enum member must have a valid name */
4276 if (!enums[i].name_off ||
4277 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4278 btf_verifier_log_type(env, t, "Invalid name");
4279 return -EINVAL;
4280 }
4281
4282 if (env->log.level == BPF_LOG_KERNEL)
4283 continue;
4284
4285 fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
4286 btf_verifier_log(env, fmt_str,
4287 __btf_name_by_offset(btf, enums[i].name_off),
4288 btf_enum64_value(enums + i));
4289 }
4290
4291 return meta_needed;
4292}
4293
4294static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
4295 u32 type_id, void *data, u8 bits_offset,
4296 struct btf_show *show)
4297{
4298 const struct btf_enum64 *enums = btf_type_enum64(t);
4299 u32 i, nr_enums = btf_type_vlen(t);
4300 void *safe_data;
4301 s64 v;
4302
4303 safe_data = btf_show_start_type(show, t, type_id, data);
4304 if (!safe_data)
4305 return;
4306
4307 v = *(u64 *)safe_data;
4308
4309 for (i = 0; i < nr_enums; i++) {
4310 if (v != btf_enum64_value(enums + i))
4311 continue;
4312
4313 btf_show_type_value(show, "%s",
4314 __btf_name_by_offset(btf,
4315 enums[i].name_off));
4316
4317 btf_show_end_type(show);
4318 return;
4319 }
4320
4321 if (btf_type_kflag(t))
4322 btf_show_type_value(show, "%lld", v);
4323 else
4324 btf_show_type_value(show, "%llu", v);
4325 btf_show_end_type(show);
4326}
4327
4328static struct btf_kind_operations enum64_ops = {
4329 .check_meta = btf_enum64_check_meta,
4330 .resolve = btf_df_resolve,
4331 .check_member = btf_enum_check_member,
4332 .check_kflag_member = btf_enum_check_kflag_member,
4333 .log_details = btf_enum_log,
4334 .show = btf_enum64_show,
4335};
4336
4337static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
4338 const struct btf_type *t,
4339 u32 meta_left)
4340{
4341 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
4342
4343 if (meta_left < meta_needed) {
4344 btf_verifier_log_basic(env, t,
4345 "meta_left:%u meta_needed:%u",
4346 meta_left, meta_needed);
4347 return -EINVAL;
4348 }
4349
4350 if (t->name_off) {
4351 btf_verifier_log_type(env, t, "Invalid name");
4352 return -EINVAL;
4353 }
4354
4355 if (btf_type_kflag(t)) {
4356 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4357 return -EINVAL;
4358 }
4359
4360 btf_verifier_log_type(env, t, NULL);
4361
4362 return meta_needed;
4363}
4364
4365static void btf_func_proto_log(struct btf_verifier_env *env,
4366 const struct btf_type *t)
4367{
4368 const struct btf_param *args = (const struct btf_param *)(t + 1);
4369 u16 nr_args = btf_type_vlen(t), i;
4370
4371 btf_verifier_log(env, "return=%u args=(", t->type);
4372 if (!nr_args) {
4373 btf_verifier_log(env, "void");
4374 goto done;
4375 }
4376
4377 if (nr_args == 1 && !args[0].type) {
4378 /* Only one vararg */
4379 btf_verifier_log(env, "vararg");
4380 goto done;
4381 }
4382
4383 btf_verifier_log(env, "%u %s", args[0].type,
4384 __btf_name_by_offset(env->btf,
4385 args[0].name_off));
4386 for (i = 1; i < nr_args - 1; i++)
4387 btf_verifier_log(env, ", %u %s", args[i].type,
4388 __btf_name_by_offset(env->btf,
4389 args[i].name_off));
4390
4391 if (nr_args > 1) {
4392 const struct btf_param *last_arg = &args[nr_args - 1];
4393
4394 if (last_arg->type)
4395 btf_verifier_log(env, ", %u %s", last_arg->type,
4396 __btf_name_by_offset(env->btf,
4397 last_arg->name_off));
4398 else
4399 btf_verifier_log(env, ", vararg");
4400 }
4401
4402done:
4403 btf_verifier_log(env, ")");
4404}
4405
4406static struct btf_kind_operations func_proto_ops = {
4407 .check_meta = btf_func_proto_check_meta,
4408 .resolve = btf_df_resolve,
4409 /*
4410 * BTF_KIND_FUNC_PROTO cannot be directly referred by
4411 * a struct's member.
4412 *
4413 * It should be a function pointer instead.
4414 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
4415 *
4416 * Hence, there is no btf_func_check_member().
4417 */
4418 .check_member = btf_df_check_member,
4419 .check_kflag_member = btf_df_check_kflag_member,
4420 .log_details = btf_func_proto_log,
4421 .show = btf_df_show,
4422};
4423
4424static s32 btf_func_check_meta(struct btf_verifier_env *env,
4425 const struct btf_type *t,
4426 u32 meta_left)
4427{
4428 if (!t->name_off ||
4429 !btf_name_valid_identifier(env->btf, t->name_off)) {
4430 btf_verifier_log_type(env, t, "Invalid name");
4431 return -EINVAL;
4432 }
4433
4434 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
4435 btf_verifier_log_type(env, t, "Invalid func linkage");
4436 return -EINVAL;
4437 }
4438
4439 if (btf_type_kflag(t)) {
4440 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4441 return -EINVAL;
4442 }
4443
4444 btf_verifier_log_type(env, t, NULL);
4445
4446 return 0;
4447}
4448
4449static int btf_func_resolve(struct btf_verifier_env *env,
4450 const struct resolve_vertex *v)
4451{
4452 const struct btf_type *t = v->t;
4453 u32 next_type_id = t->type;
4454 int err;
4455
4456 err = btf_func_check(env, t);
4457 if (err)
4458 return err;
4459
4460 env_stack_pop_resolved(env, next_type_id, 0);
4461 return 0;
4462}
4463
4464static struct btf_kind_operations func_ops = {
4465 .check_meta = btf_func_check_meta,
4466 .resolve = btf_func_resolve,
4467 .check_member = btf_df_check_member,
4468 .check_kflag_member = btf_df_check_kflag_member,
4469 .log_details = btf_ref_type_log,
4470 .show = btf_df_show,
4471};
4472
4473static s32 btf_var_check_meta(struct btf_verifier_env *env,
4474 const struct btf_type *t,
4475 u32 meta_left)
4476{
4477 const struct btf_var *var;
4478 u32 meta_needed = sizeof(*var);
4479
4480 if (meta_left < meta_needed) {
4481 btf_verifier_log_basic(env, t,
4482 "meta_left:%u meta_needed:%u",
4483 meta_left, meta_needed);
4484 return -EINVAL;
4485 }
4486
4487 if (btf_type_vlen(t)) {
4488 btf_verifier_log_type(env, t, "vlen != 0");
4489 return -EINVAL;
4490 }
4491
4492 if (btf_type_kflag(t)) {
4493 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4494 return -EINVAL;
4495 }
4496
4497 if (!t->name_off ||
4498 !__btf_name_valid(env->btf, t->name_off)) {
4499 btf_verifier_log_type(env, t, "Invalid name");
4500 return -EINVAL;
4501 }
4502
4503 /* A var cannot be in type void */
4504 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4505 btf_verifier_log_type(env, t, "Invalid type_id");
4506 return -EINVAL;
4507 }
4508
4509 var = btf_type_var(t);
4510 if (var->linkage != BTF_VAR_STATIC &&
4511 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4512 btf_verifier_log_type(env, t, "Linkage not supported");
4513 return -EINVAL;
4514 }
4515
4516 btf_verifier_log_type(env, t, NULL);
4517
4518 return meta_needed;
4519}
4520
4521static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4522{
4523 const struct btf_var *var = btf_type_var(t);
4524
4525 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4526}
4527
4528static const struct btf_kind_operations var_ops = {
4529 .check_meta = btf_var_check_meta,
4530 .resolve = btf_var_resolve,
4531 .check_member = btf_df_check_member,
4532 .check_kflag_member = btf_df_check_kflag_member,
4533 .log_details = btf_var_log,
4534 .show = btf_var_show,
4535};
4536
4537static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4538 const struct btf_type *t,
4539 u32 meta_left)
4540{
4541 const struct btf_var_secinfo *vsi;
4542 u64 last_vsi_end_off = 0, sum = 0;
4543 u32 i, meta_needed;
4544
4545 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4546 if (meta_left < meta_needed) {
4547 btf_verifier_log_basic(env, t,
4548 "meta_left:%u meta_needed:%u",
4549 meta_left, meta_needed);
4550 return -EINVAL;
4551 }
4552
4553 if (!t->size) {
4554 btf_verifier_log_type(env, t, "size == 0");
4555 return -EINVAL;
4556 }
4557
4558 if (btf_type_kflag(t)) {
4559 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4560 return -EINVAL;
4561 }
4562
4563 if (!t->name_off ||
4564 !btf_name_valid_section(env->btf, t->name_off)) {
4565 btf_verifier_log_type(env, t, "Invalid name");
4566 return -EINVAL;
4567 }
4568
4569 btf_verifier_log_type(env, t, NULL);
4570
4571 for_each_vsi(i, t, vsi) {
4572 /* A var cannot be in type void */
4573 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4574 btf_verifier_log_vsi(env, t, vsi,
4575 "Invalid type_id");
4576 return -EINVAL;
4577 }
4578
4579 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4580 btf_verifier_log_vsi(env, t, vsi,
4581 "Invalid offset");
4582 return -EINVAL;
4583 }
4584
4585 if (!vsi->size || vsi->size > t->size) {
4586 btf_verifier_log_vsi(env, t, vsi,
4587 "Invalid size");
4588 return -EINVAL;
4589 }
4590
4591 last_vsi_end_off = vsi->offset + vsi->size;
4592 if (last_vsi_end_off > t->size) {
4593 btf_verifier_log_vsi(env, t, vsi,
4594 "Invalid offset+size");
4595 return -EINVAL;
4596 }
4597
4598 btf_verifier_log_vsi(env, t, vsi, NULL);
4599 sum += vsi->size;
4600 }
4601
4602 if (t->size < sum) {
4603 btf_verifier_log_type(env, t, "Invalid btf_info size");
4604 return -EINVAL;
4605 }
4606
4607 return meta_needed;
4608}
4609
4610static int btf_datasec_resolve(struct btf_verifier_env *env,
4611 const struct resolve_vertex *v)
4612{
4613 const struct btf_var_secinfo *vsi;
4614 struct btf *btf = env->btf;
4615 u16 i;
4616
4617 env->resolve_mode = RESOLVE_TBD;
4618 for_each_vsi_from(i, v->next_member, v->t, vsi) {
4619 u32 var_type_id = vsi->type, type_id, type_size = 0;
4620 const struct btf_type *var_type = btf_type_by_id(env->btf,
4621 var_type_id);
4622 if (!var_type || !btf_type_is_var(var_type)) {
4623 btf_verifier_log_vsi(env, v->t, vsi,
4624 "Not a VAR kind member");
4625 return -EINVAL;
4626 }
4627
4628 if (!env_type_is_resolve_sink(env, var_type) &&
4629 !env_type_is_resolved(env, var_type_id)) {
4630 env_stack_set_next_member(env, i + 1);
4631 return env_stack_push(env, var_type, var_type_id);
4632 }
4633
4634 type_id = var_type->type;
4635 if (!btf_type_id_size(btf, &type_id, &type_size)) {
4636 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4637 return -EINVAL;
4638 }
4639
4640 if (vsi->size < type_size) {
4641 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4642 return -EINVAL;
4643 }
4644 }
4645
4646 env_stack_pop_resolved(env, 0, 0);
4647 return 0;
4648}
4649
4650static void btf_datasec_log(struct btf_verifier_env *env,
4651 const struct btf_type *t)
4652{
4653 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4654}
4655
4656static void btf_datasec_show(const struct btf *btf,
4657 const struct btf_type *t, u32 type_id,
4658 void *data, u8 bits_offset,
4659 struct btf_show *show)
4660{
4661 const struct btf_var_secinfo *vsi;
4662 const struct btf_type *var;
4663 u32 i;
4664
4665 if (!btf_show_start_type(show, t, type_id, data))
4666 return;
4667
4668 btf_show_type_value(show, "section (\"%s\") = {",
4669 __btf_name_by_offset(btf, t->name_off));
4670 for_each_vsi(i, t, vsi) {
4671 var = btf_type_by_id(btf, vsi->type);
4672 if (i)
4673 btf_show(show, ",");
4674 btf_type_ops(var)->show(btf, var, vsi->type,
4675 data + vsi->offset, bits_offset, show);
4676 }
4677 btf_show_end_type(show);
4678}
4679
4680static const struct btf_kind_operations datasec_ops = {
4681 .check_meta = btf_datasec_check_meta,
4682 .resolve = btf_datasec_resolve,
4683 .check_member = btf_df_check_member,
4684 .check_kflag_member = btf_df_check_kflag_member,
4685 .log_details = btf_datasec_log,
4686 .show = btf_datasec_show,
4687};
4688
4689static s32 btf_float_check_meta(struct btf_verifier_env *env,
4690 const struct btf_type *t,
4691 u32 meta_left)
4692{
4693 if (btf_type_vlen(t)) {
4694 btf_verifier_log_type(env, t, "vlen != 0");
4695 return -EINVAL;
4696 }
4697
4698 if (btf_type_kflag(t)) {
4699 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4700 return -EINVAL;
4701 }
4702
4703 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4704 t->size != 16) {
4705 btf_verifier_log_type(env, t, "Invalid type_size");
4706 return -EINVAL;
4707 }
4708
4709 btf_verifier_log_type(env, t, NULL);
4710
4711 return 0;
4712}
4713
4714static int btf_float_check_member(struct btf_verifier_env *env,
4715 const struct btf_type *struct_type,
4716 const struct btf_member *member,
4717 const struct btf_type *member_type)
4718{
4719 u64 start_offset_bytes;
4720 u64 end_offset_bytes;
4721 u64 misalign_bits;
4722 u64 align_bytes;
4723 u64 align_bits;
4724
4725 /* Different architectures have different alignment requirements, so
4726 * here we check only for the reasonable minimum. This way we ensure
4727 * that types after CO-RE can pass the kernel BTF verifier.
4728 */
4729 align_bytes = min_t(u64, sizeof(void *), member_type->size);
4730 align_bits = align_bytes * BITS_PER_BYTE;
4731 div64_u64_rem(member->offset, align_bits, &misalign_bits);
4732 if (misalign_bits) {
4733 btf_verifier_log_member(env, struct_type, member,
4734 "Member is not properly aligned");
4735 return -EINVAL;
4736 }
4737
4738 start_offset_bytes = member->offset / BITS_PER_BYTE;
4739 end_offset_bytes = start_offset_bytes + member_type->size;
4740 if (end_offset_bytes > struct_type->size) {
4741 btf_verifier_log_member(env, struct_type, member,
4742 "Member exceeds struct_size");
4743 return -EINVAL;
4744 }
4745
4746 return 0;
4747}
4748
4749static void btf_float_log(struct btf_verifier_env *env,
4750 const struct btf_type *t)
4751{
4752 btf_verifier_log(env, "size=%u", t->size);
4753}
4754
4755static const struct btf_kind_operations float_ops = {
4756 .check_meta = btf_float_check_meta,
4757 .resolve = btf_df_resolve,
4758 .check_member = btf_float_check_member,
4759 .check_kflag_member = btf_generic_check_kflag_member,
4760 .log_details = btf_float_log,
4761 .show = btf_df_show,
4762};
4763
4764static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4765 const struct btf_type *t,
4766 u32 meta_left)
4767{
4768 const struct btf_decl_tag *tag;
4769 u32 meta_needed = sizeof(*tag);
4770 s32 component_idx;
4771 const char *value;
4772
4773 if (meta_left < meta_needed) {
4774 btf_verifier_log_basic(env, t,
4775 "meta_left:%u meta_needed:%u",
4776 meta_left, meta_needed);
4777 return -EINVAL;
4778 }
4779
4780 value = btf_name_by_offset(env->btf, t->name_off);
4781 if (!value || !value[0]) {
4782 btf_verifier_log_type(env, t, "Invalid value");
4783 return -EINVAL;
4784 }
4785
4786 if (btf_type_vlen(t)) {
4787 btf_verifier_log_type(env, t, "vlen != 0");
4788 return -EINVAL;
4789 }
4790
4791 if (btf_type_kflag(t)) {
4792 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4793 return -EINVAL;
4794 }
4795
4796 component_idx = btf_type_decl_tag(t)->component_idx;
4797 if (component_idx < -1) {
4798 btf_verifier_log_type(env, t, "Invalid component_idx");
4799 return -EINVAL;
4800 }
4801
4802 btf_verifier_log_type(env, t, NULL);
4803
4804 return meta_needed;
4805}
4806
4807static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4808 const struct resolve_vertex *v)
4809{
4810 const struct btf_type *next_type;
4811 const struct btf_type *t = v->t;
4812 u32 next_type_id = t->type;
4813 struct btf *btf = env->btf;
4814 s32 component_idx;
4815 u32 vlen;
4816
4817 next_type = btf_type_by_id(btf, next_type_id);
4818 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4819 btf_verifier_log_type(env, v->t, "Invalid type_id");
4820 return -EINVAL;
4821 }
4822
4823 if (!env_type_is_resolve_sink(env, next_type) &&
4824 !env_type_is_resolved(env, next_type_id))
4825 return env_stack_push(env, next_type, next_type_id);
4826
4827 component_idx = btf_type_decl_tag(t)->component_idx;
4828 if (component_idx != -1) {
4829 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4830 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4831 return -EINVAL;
4832 }
4833
4834 if (btf_type_is_struct(next_type)) {
4835 vlen = btf_type_vlen(next_type);
4836 } else {
4837 /* next_type should be a function */
4838 next_type = btf_type_by_id(btf, next_type->type);
4839 vlen = btf_type_vlen(next_type);
4840 }
4841
4842 if ((u32)component_idx >= vlen) {
4843 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4844 return -EINVAL;
4845 }
4846 }
4847
4848 env_stack_pop_resolved(env, next_type_id, 0);
4849
4850 return 0;
4851}
4852
4853static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
4854{
4855 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
4856 btf_type_decl_tag(t)->component_idx);
4857}
4858
4859static const struct btf_kind_operations decl_tag_ops = {
4860 .check_meta = btf_decl_tag_check_meta,
4861 .resolve = btf_decl_tag_resolve,
4862 .check_member = btf_df_check_member,
4863 .check_kflag_member = btf_df_check_kflag_member,
4864 .log_details = btf_decl_tag_log,
4865 .show = btf_df_show,
4866};
4867
4868static int btf_func_proto_check(struct btf_verifier_env *env,
4869 const struct btf_type *t)
4870{
4871 const struct btf_type *ret_type;
4872 const struct btf_param *args;
4873 const struct btf *btf;
4874 u16 nr_args, i;
4875 int err;
4876
4877 btf = env->btf;
4878 args = (const struct btf_param *)(t + 1);
4879 nr_args = btf_type_vlen(t);
4880
4881 /* Check func return type which could be "void" (t->type == 0) */
4882 if (t->type) {
4883 u32 ret_type_id = t->type;
4884
4885 ret_type = btf_type_by_id(btf, ret_type_id);
4886 if (!ret_type) {
4887 btf_verifier_log_type(env, t, "Invalid return type");
4888 return -EINVAL;
4889 }
4890
4891 if (btf_type_is_resolve_source_only(ret_type)) {
4892 btf_verifier_log_type(env, t, "Invalid return type");
4893 return -EINVAL;
4894 }
4895
4896 if (btf_type_needs_resolve(ret_type) &&
4897 !env_type_is_resolved(env, ret_type_id)) {
4898 err = btf_resolve(env, ret_type, ret_type_id);
4899 if (err)
4900 return err;
4901 }
4902
4903 /* Ensure the return type is a type that has a size */
4904 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
4905 btf_verifier_log_type(env, t, "Invalid return type");
4906 return -EINVAL;
4907 }
4908 }
4909
4910 if (!nr_args)
4911 return 0;
4912
4913 /* Last func arg type_id could be 0 if it is a vararg */
4914 if (!args[nr_args - 1].type) {
4915 if (args[nr_args - 1].name_off) {
4916 btf_verifier_log_type(env, t, "Invalid arg#%u",
4917 nr_args);
4918 return -EINVAL;
4919 }
4920 nr_args--;
4921 }
4922
4923 for (i = 0; i < nr_args; i++) {
4924 const struct btf_type *arg_type;
4925 u32 arg_type_id;
4926
4927 arg_type_id = args[i].type;
4928 arg_type = btf_type_by_id(btf, arg_type_id);
4929 if (!arg_type) {
4930 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4931 return -EINVAL;
4932 }
4933
4934 if (btf_type_is_resolve_source_only(arg_type)) {
4935 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4936 return -EINVAL;
4937 }
4938
4939 if (args[i].name_off &&
4940 (!btf_name_offset_valid(btf, args[i].name_off) ||
4941 !btf_name_valid_identifier(btf, args[i].name_off))) {
4942 btf_verifier_log_type(env, t,
4943 "Invalid arg#%u", i + 1);
4944 return -EINVAL;
4945 }
4946
4947 if (btf_type_needs_resolve(arg_type) &&
4948 !env_type_is_resolved(env, arg_type_id)) {
4949 err = btf_resolve(env, arg_type, arg_type_id);
4950 if (err)
4951 return err;
4952 }
4953
4954 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4955 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4956 return -EINVAL;
4957 }
4958 }
4959
4960 return 0;
4961}
4962
4963static int btf_func_check(struct btf_verifier_env *env,
4964 const struct btf_type *t)
4965{
4966 const struct btf_type *proto_type;
4967 const struct btf_param *args;
4968 const struct btf *btf;
4969 u16 nr_args, i;
4970
4971 btf = env->btf;
4972 proto_type = btf_type_by_id(btf, t->type);
4973
4974 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4975 btf_verifier_log_type(env, t, "Invalid type_id");
4976 return -EINVAL;
4977 }
4978
4979 args = (const struct btf_param *)(proto_type + 1);
4980 nr_args = btf_type_vlen(proto_type);
4981 for (i = 0; i < nr_args; i++) {
4982 if (!args[i].name_off && args[i].type) {
4983 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4984 return -EINVAL;
4985 }
4986 }
4987
4988 return 0;
4989}
4990
4991static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4992 [BTF_KIND_INT] = &int_ops,
4993 [BTF_KIND_PTR] = &ptr_ops,
4994 [BTF_KIND_ARRAY] = &array_ops,
4995 [BTF_KIND_STRUCT] = &struct_ops,
4996 [BTF_KIND_UNION] = &struct_ops,
4997 [BTF_KIND_ENUM] = &enum_ops,
4998 [BTF_KIND_FWD] = &fwd_ops,
4999 [BTF_KIND_TYPEDEF] = &modifier_ops,
5000 [BTF_KIND_VOLATILE] = &modifier_ops,
5001 [BTF_KIND_CONST] = &modifier_ops,
5002 [BTF_KIND_RESTRICT] = &modifier_ops,
5003 [BTF_KIND_FUNC] = &func_ops,
5004 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
5005 [BTF_KIND_VAR] = &var_ops,
5006 [BTF_KIND_DATASEC] = &datasec_ops,
5007 [BTF_KIND_FLOAT] = &float_ops,
5008 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
5009 [BTF_KIND_TYPE_TAG] = &modifier_ops,
5010 [BTF_KIND_ENUM64] = &enum64_ops,
5011};
5012
5013static s32 btf_check_meta(struct btf_verifier_env *env,
5014 const struct btf_type *t,
5015 u32 meta_left)
5016{
5017 u32 saved_meta_left = meta_left;
5018 s32 var_meta_size;
5019
5020 if (meta_left < sizeof(*t)) {
5021 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
5022 env->log_type_id, meta_left, sizeof(*t));
5023 return -EINVAL;
5024 }
5025 meta_left -= sizeof(*t);
5026
5027 if (t->info & ~BTF_INFO_MASK) {
5028 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
5029 env->log_type_id, t->info);
5030 return -EINVAL;
5031 }
5032
5033 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
5034 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
5035 btf_verifier_log(env, "[%u] Invalid kind:%u",
5036 env->log_type_id, BTF_INFO_KIND(t->info));
5037 return -EINVAL;
5038 }
5039
5040 if (!btf_name_offset_valid(env->btf, t->name_off)) {
5041 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
5042 env->log_type_id, t->name_off);
5043 return -EINVAL;
5044 }
5045
5046 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
5047 if (var_meta_size < 0)
5048 return var_meta_size;
5049
5050 meta_left -= var_meta_size;
5051
5052 return saved_meta_left - meta_left;
5053}
5054
5055static int btf_check_all_metas(struct btf_verifier_env *env)
5056{
5057 struct btf *btf = env->btf;
5058 struct btf_header *hdr;
5059 void *cur, *end;
5060
5061 hdr = &btf->hdr;
5062 cur = btf->nohdr_data + hdr->type_off;
5063 end = cur + hdr->type_len;
5064
5065 env->log_type_id = btf->base_btf ? btf->start_id : 1;
5066 while (cur < end) {
5067 struct btf_type *t = cur;
5068 s32 meta_size;
5069
5070 meta_size = btf_check_meta(env, t, end - cur);
5071 if (meta_size < 0)
5072 return meta_size;
5073
5074 btf_add_type(env, t);
5075 cur += meta_size;
5076 env->log_type_id++;
5077 }
5078
5079 return 0;
5080}
5081
5082static bool btf_resolve_valid(struct btf_verifier_env *env,
5083 const struct btf_type *t,
5084 u32 type_id)
5085{
5086 struct btf *btf = env->btf;
5087
5088 if (!env_type_is_resolved(env, type_id))
5089 return false;
5090
5091 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
5092 return !btf_resolved_type_id(btf, type_id) &&
5093 !btf_resolved_type_size(btf, type_id);
5094
5095 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
5096 return btf_resolved_type_id(btf, type_id) &&
5097 !btf_resolved_type_size(btf, type_id);
5098
5099 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
5100 btf_type_is_var(t)) {
5101 t = btf_type_id_resolve(btf, &type_id);
5102 return t &&
5103 !btf_type_is_modifier(t) &&
5104 !btf_type_is_var(t) &&
5105 !btf_type_is_datasec(t);
5106 }
5107
5108 if (btf_type_is_array(t)) {
5109 const struct btf_array *array = btf_type_array(t);
5110 const struct btf_type *elem_type;
5111 u32 elem_type_id = array->type;
5112 u32 elem_size;
5113
5114 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
5115 return elem_type && !btf_type_is_modifier(elem_type) &&
5116 (array->nelems * elem_size ==
5117 btf_resolved_type_size(btf, type_id));
5118 }
5119
5120 return false;
5121}
5122
5123static int btf_resolve(struct btf_verifier_env *env,
5124 const struct btf_type *t, u32 type_id)
5125{
5126 u32 save_log_type_id = env->log_type_id;
5127 const struct resolve_vertex *v;
5128 int err = 0;
5129
5130 env->resolve_mode = RESOLVE_TBD;
5131 env_stack_push(env, t, type_id);
5132 while (!err && (v = env_stack_peak(env))) {
5133 env->log_type_id = v->type_id;
5134 err = btf_type_ops(v->t)->resolve(env, v);
5135 }
5136
5137 env->log_type_id = type_id;
5138 if (err == -E2BIG) {
5139 btf_verifier_log_type(env, t,
5140 "Exceeded max resolving depth:%u",
5141 MAX_RESOLVE_DEPTH);
5142 } else if (err == -EEXIST) {
5143 btf_verifier_log_type(env, t, "Loop detected");
5144 }
5145
5146 /* Final sanity check */
5147 if (!err && !btf_resolve_valid(env, t, type_id)) {
5148 btf_verifier_log_type(env, t, "Invalid resolve state");
5149 err = -EINVAL;
5150 }
5151
5152 env->log_type_id = save_log_type_id;
5153 return err;
5154}
5155
5156static int btf_check_all_types(struct btf_verifier_env *env)
5157{
5158 struct btf *btf = env->btf;
5159 const struct btf_type *t;
5160 u32 type_id, i;
5161 int err;
5162
5163 err = env_resolve_init(env);
5164 if (err)
5165 return err;
5166
5167 env->phase++;
5168 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
5169 type_id = btf->start_id + i;
5170 t = btf_type_by_id(btf, type_id);
5171
5172 env->log_type_id = type_id;
5173 if (btf_type_needs_resolve(t) &&
5174 !env_type_is_resolved(env, type_id)) {
5175 err = btf_resolve(env, t, type_id);
5176 if (err)
5177 return err;
5178 }
5179
5180 if (btf_type_is_func_proto(t)) {
5181 err = btf_func_proto_check(env, t);
5182 if (err)
5183 return err;
5184 }
5185 }
5186
5187 return 0;
5188}
5189
5190static int btf_parse_type_sec(struct btf_verifier_env *env)
5191{
5192 const struct btf_header *hdr = &env->btf->hdr;
5193 int err;
5194
5195 /* Type section must align to 4 bytes */
5196 if (hdr->type_off & (sizeof(u32) - 1)) {
5197 btf_verifier_log(env, "Unaligned type_off");
5198 return -EINVAL;
5199 }
5200
5201 if (!env->btf->base_btf && !hdr->type_len) {
5202 btf_verifier_log(env, "No type found");
5203 return -EINVAL;
5204 }
5205
5206 err = btf_check_all_metas(env);
5207 if (err)
5208 return err;
5209
5210 return btf_check_all_types(env);
5211}
5212
5213static int btf_parse_str_sec(struct btf_verifier_env *env)
5214{
5215 const struct btf_header *hdr;
5216 struct btf *btf = env->btf;
5217 const char *start, *end;
5218
5219 hdr = &btf->hdr;
5220 start = btf->nohdr_data + hdr->str_off;
5221 end = start + hdr->str_len;
5222
5223 if (end != btf->data + btf->data_size) {
5224 btf_verifier_log(env, "String section is not at the end");
5225 return -EINVAL;
5226 }
5227
5228 btf->strings = start;
5229
5230 if (btf->base_btf && !hdr->str_len)
5231 return 0;
5232 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
5233 btf_verifier_log(env, "Invalid string section");
5234 return -EINVAL;
5235 }
5236 if (!btf->base_btf && start[0]) {
5237 btf_verifier_log(env, "Invalid string section");
5238 return -EINVAL;
5239 }
5240
5241 return 0;
5242}
5243
5244static const size_t btf_sec_info_offset[] = {
5245 offsetof(struct btf_header, type_off),
5246 offsetof(struct btf_header, str_off),
5247};
5248
5249static int btf_sec_info_cmp(const void *a, const void *b)
5250{
5251 const struct btf_sec_info *x = a;
5252 const struct btf_sec_info *y = b;
5253
5254 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
5255}
5256
5257static int btf_check_sec_info(struct btf_verifier_env *env,
5258 u32 btf_data_size)
5259{
5260 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
5261 u32 total, expected_total, i;
5262 const struct btf_header *hdr;
5263 const struct btf *btf;
5264
5265 btf = env->btf;
5266 hdr = &btf->hdr;
5267
5268 /* Populate the secs from hdr */
5269 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
5270 secs[i] = *(struct btf_sec_info *)((void *)hdr +
5271 btf_sec_info_offset[i]);
5272
5273 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
5274 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
5275
5276 /* Check for gaps and overlap among sections */
5277 total = 0;
5278 expected_total = btf_data_size - hdr->hdr_len;
5279 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
5280 if (expected_total < secs[i].off) {
5281 btf_verifier_log(env, "Invalid section offset");
5282 return -EINVAL;
5283 }
5284 if (total < secs[i].off) {
5285 /* gap */
5286 btf_verifier_log(env, "Unsupported section found");
5287 return -EINVAL;
5288 }
5289 if (total > secs[i].off) {
5290 btf_verifier_log(env, "Section overlap found");
5291 return -EINVAL;
5292 }
5293 if (expected_total - total < secs[i].len) {
5294 btf_verifier_log(env,
5295 "Total section length too long");
5296 return -EINVAL;
5297 }
5298 total += secs[i].len;
5299 }
5300
5301 /* There is data other than hdr and known sections */
5302 if (expected_total != total) {
5303 btf_verifier_log(env, "Unsupported section found");
5304 return -EINVAL;
5305 }
5306
5307 return 0;
5308}
5309
5310static int btf_parse_hdr(struct btf_verifier_env *env)
5311{
5312 u32 hdr_len, hdr_copy, btf_data_size;
5313 const struct btf_header *hdr;
5314 struct btf *btf;
5315
5316 btf = env->btf;
5317 btf_data_size = btf->data_size;
5318
5319 if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
5320 btf_verifier_log(env, "hdr_len not found");
5321 return -EINVAL;
5322 }
5323
5324 hdr = btf->data;
5325 hdr_len = hdr->hdr_len;
5326 if (btf_data_size < hdr_len) {
5327 btf_verifier_log(env, "btf_header not found");
5328 return -EINVAL;
5329 }
5330
5331 /* Ensure the unsupported header fields are zero */
5332 if (hdr_len > sizeof(btf->hdr)) {
5333 u8 *expected_zero = btf->data + sizeof(btf->hdr);
5334 u8 *end = btf->data + hdr_len;
5335
5336 for (; expected_zero < end; expected_zero++) {
5337 if (*expected_zero) {
5338 btf_verifier_log(env, "Unsupported btf_header");
5339 return -E2BIG;
5340 }
5341 }
5342 }
5343
5344 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
5345 memcpy(&btf->hdr, btf->data, hdr_copy);
5346
5347 hdr = &btf->hdr;
5348
5349 btf_verifier_log_hdr(env, btf_data_size);
5350
5351 if (hdr->magic != BTF_MAGIC) {
5352 btf_verifier_log(env, "Invalid magic");
5353 return -EINVAL;
5354 }
5355
5356 if (hdr->version != BTF_VERSION) {
5357 btf_verifier_log(env, "Unsupported version");
5358 return -ENOTSUPP;
5359 }
5360
5361 if (hdr->flags) {
5362 btf_verifier_log(env, "Unsupported flags");
5363 return -ENOTSUPP;
5364 }
5365
5366 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
5367 btf_verifier_log(env, "No data");
5368 return -EINVAL;
5369 }
5370
5371 return btf_check_sec_info(env, btf_data_size);
5372}
5373
5374static const char *alloc_obj_fields[] = {
5375 "bpf_spin_lock",
5376 "bpf_list_head",
5377 "bpf_list_node",
5378 "bpf_rb_root",
5379 "bpf_rb_node",
5380 "bpf_refcount",
5381};
5382
5383static struct btf_struct_metas *
5384btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
5385{
5386 union {
5387 struct btf_id_set set;
5388 struct {
5389 u32 _cnt;
5390 u32 _ids[ARRAY_SIZE(alloc_obj_fields)];
5391 } _arr;
5392 } aof;
5393 struct btf_struct_metas *tab = NULL;
5394 int i, n, id, ret;
5395
5396 BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
5397 BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
5398
5399 memset(&aof, 0, sizeof(aof));
5400 for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
5401 /* Try to find whether this special type exists in user BTF, and
5402 * if so remember its ID so we can easily find it among members
5403 * of structs that we iterate in the next loop.
5404 */
5405 id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
5406 if (id < 0)
5407 continue;
5408 aof.set.ids[aof.set.cnt++] = id;
5409 }
5410
5411 if (!aof.set.cnt)
5412 return NULL;
5413 sort(&aof.set.ids, aof.set.cnt, sizeof(aof.set.ids[0]), btf_id_cmp_func, NULL);
5414
5415 n = btf_nr_types(btf);
5416 for (i = 1; i < n; i++) {
5417 struct btf_struct_metas *new_tab;
5418 const struct btf_member *member;
5419 struct btf_struct_meta *type;
5420 struct btf_record *record;
5421 const struct btf_type *t;
5422 int j, tab_cnt;
5423
5424 t = btf_type_by_id(btf, i);
5425 if (!t) {
5426 ret = -EINVAL;
5427 goto free;
5428 }
5429 if (!__btf_type_is_struct(t))
5430 continue;
5431
5432 cond_resched();
5433
5434 for_each_member(j, t, member) {
5435 if (btf_id_set_contains(&aof.set, member->type))
5436 goto parse;
5437 }
5438 continue;
5439 parse:
5440 tab_cnt = tab ? tab->cnt : 0;
5441 new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),
5442 GFP_KERNEL | __GFP_NOWARN);
5443 if (!new_tab) {
5444 ret = -ENOMEM;
5445 goto free;
5446 }
5447 if (!tab)
5448 new_tab->cnt = 0;
5449 tab = new_tab;
5450
5451 type = &tab->types[tab->cnt];
5452 type->btf_id = i;
5453 record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE |
5454 BPF_RB_ROOT | BPF_RB_NODE | BPF_REFCOUNT, t->size);
5455 /* The record cannot be unset, treat it as an error if so */
5456 if (IS_ERR_OR_NULL(record)) {
5457 ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
5458 goto free;
5459 }
5460 type->record = record;
5461 tab->cnt++;
5462 }
5463 return tab;
5464free:
5465 btf_struct_metas_free(tab);
5466 return ERR_PTR(ret);
5467}
5468
5469struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
5470{
5471 struct btf_struct_metas *tab;
5472
5473 BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
5474 tab = btf->struct_meta_tab;
5475 if (!tab)
5476 return NULL;
5477 return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
5478}
5479
5480static int btf_check_type_tags(struct btf_verifier_env *env,
5481 struct btf *btf, int start_id)
5482{
5483 int i, n, good_id = start_id - 1;
5484 bool in_tags;
5485
5486 n = btf_nr_types(btf);
5487 for (i = start_id; i < n; i++) {
5488 const struct btf_type *t;
5489 int chain_limit = 32;
5490 u32 cur_id = i;
5491
5492 t = btf_type_by_id(btf, i);
5493 if (!t)
5494 return -EINVAL;
5495 if (!btf_type_is_modifier(t))
5496 continue;
5497
5498 cond_resched();
5499
5500 in_tags = btf_type_is_type_tag(t);
5501 while (btf_type_is_modifier(t)) {
5502 if (!chain_limit--) {
5503 btf_verifier_log(env, "Max chain length or cycle detected");
5504 return -ELOOP;
5505 }
5506 if (btf_type_is_type_tag(t)) {
5507 if (!in_tags) {
5508 btf_verifier_log(env, "Type tags don't precede modifiers");
5509 return -EINVAL;
5510 }
5511 } else if (in_tags) {
5512 in_tags = false;
5513 }
5514 if (cur_id <= good_id)
5515 break;
5516 /* Move to next type */
5517 cur_id = t->type;
5518 t = btf_type_by_id(btf, cur_id);
5519 if (!t)
5520 return -EINVAL;
5521 }
5522 good_id = i;
5523 }
5524 return 0;
5525}
5526
5527static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
5528{
5529 u32 log_true_size;
5530 int err;
5531
5532 err = bpf_vlog_finalize(log, &log_true_size);
5533
5534 if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
5535 copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
5536 &log_true_size, sizeof(log_true_size)))
5537 err = -EFAULT;
5538
5539 return err;
5540}
5541
5542static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
5543{
5544 bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
5545 char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
5546 struct btf_struct_metas *struct_meta_tab;
5547 struct btf_verifier_env *env = NULL;
5548 struct btf *btf = NULL;
5549 u8 *data;
5550 int err, ret;
5551
5552 if (attr->btf_size > BTF_MAX_SIZE)
5553 return ERR_PTR(-E2BIG);
5554
5555 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5556 if (!env)
5557 return ERR_PTR(-ENOMEM);
5558
5559 /* user could have requested verbose verifier output
5560 * and supplied buffer to store the verification trace
5561 */
5562 err = bpf_vlog_init(&env->log, attr->btf_log_level,
5563 log_ubuf, attr->btf_log_size);
5564 if (err)
5565 goto errout_free;
5566
5567 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5568 if (!btf) {
5569 err = -ENOMEM;
5570 goto errout;
5571 }
5572 env->btf = btf;
5573
5574 data = kvmalloc(attr->btf_size, GFP_KERNEL | __GFP_NOWARN);
5575 if (!data) {
5576 err = -ENOMEM;
5577 goto errout;
5578 }
5579
5580 btf->data = data;
5581 btf->data_size = attr->btf_size;
5582
5583 if (copy_from_bpfptr(data, btf_data, attr->btf_size)) {
5584 err = -EFAULT;
5585 goto errout;
5586 }
5587
5588 err = btf_parse_hdr(env);
5589 if (err)
5590 goto errout;
5591
5592 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5593
5594 err = btf_parse_str_sec(env);
5595 if (err)
5596 goto errout;
5597
5598 err = btf_parse_type_sec(env);
5599 if (err)
5600 goto errout;
5601
5602 err = btf_check_type_tags(env, btf, 1);
5603 if (err)
5604 goto errout;
5605
5606 struct_meta_tab = btf_parse_struct_metas(&env->log, btf);
5607 if (IS_ERR(struct_meta_tab)) {
5608 err = PTR_ERR(struct_meta_tab);
5609 goto errout;
5610 }
5611 btf->struct_meta_tab = struct_meta_tab;
5612
5613 if (struct_meta_tab) {
5614 int i;
5615
5616 for (i = 0; i < struct_meta_tab->cnt; i++) {
5617 err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
5618 if (err < 0)
5619 goto errout_meta;
5620 }
5621 }
5622
5623 err = finalize_log(&env->log, uattr, uattr_size);
5624 if (err)
5625 goto errout_free;
5626
5627 btf_verifier_env_free(env);
5628 refcount_set(&btf->refcnt, 1);
5629 return btf;
5630
5631errout_meta:
5632 btf_free_struct_meta_tab(btf);
5633errout:
5634 /* overwrite err with -ENOSPC or -EFAULT */
5635 ret = finalize_log(&env->log, uattr, uattr_size);
5636 if (ret)
5637 err = ret;
5638errout_free:
5639 btf_verifier_env_free(env);
5640 if (btf)
5641 btf_free(btf);
5642 return ERR_PTR(err);
5643}
5644
5645extern char __weak __start_BTF[];
5646extern char __weak __stop_BTF[];
5647extern struct btf *btf_vmlinux;
5648
5649#define BPF_MAP_TYPE(_id, _ops)
5650#define BPF_LINK_TYPE(_id, _name)
5651static union {
5652 struct bpf_ctx_convert {
5653#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5654 prog_ctx_type _id##_prog; \
5655 kern_ctx_type _id##_kern;
5656#include <linux/bpf_types.h>
5657#undef BPF_PROG_TYPE
5658 } *__t;
5659 /* 't' is written once under lock. Read many times. */
5660 const struct btf_type *t;
5661} bpf_ctx_convert;
5662enum {
5663#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5664 __ctx_convert##_id,
5665#include <linux/bpf_types.h>
5666#undef BPF_PROG_TYPE
5667 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
5668};
5669static u8 bpf_ctx_convert_map[] = {
5670#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5671 [_id] = __ctx_convert##_id,
5672#include <linux/bpf_types.h>
5673#undef BPF_PROG_TYPE
5674 0, /* avoid empty array */
5675};
5676#undef BPF_MAP_TYPE
5677#undef BPF_LINK_TYPE
5678
5679static const struct btf_type *find_canonical_prog_ctx_type(enum bpf_prog_type prog_type)
5680{
5681 const struct btf_type *conv_struct;
5682 const struct btf_member *ctx_type;
5683
5684 conv_struct = bpf_ctx_convert.t;
5685 if (!conv_struct)
5686 return NULL;
5687 /* prog_type is valid bpf program type. No need for bounds check. */
5688 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5689 /* ctx_type is a pointer to prog_ctx_type in vmlinux.
5690 * Like 'struct __sk_buff'
5691 */
5692 return btf_type_by_id(btf_vmlinux, ctx_type->type);
5693}
5694
5695static int find_kern_ctx_type_id(enum bpf_prog_type prog_type)
5696{
5697 const struct btf_type *conv_struct;
5698 const struct btf_member *ctx_type;
5699
5700 conv_struct = bpf_ctx_convert.t;
5701 if (!conv_struct)
5702 return -EFAULT;
5703 /* prog_type is valid bpf program type. No need for bounds check. */
5704 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5705 /* ctx_type is a pointer to prog_ctx_type in vmlinux.
5706 * Like 'struct sk_buff'
5707 */
5708 return ctx_type->type;
5709}
5710
5711bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5712 const struct btf_type *t, enum bpf_prog_type prog_type,
5713 int arg)
5714{
5715 const struct btf_type *ctx_type;
5716 const char *tname, *ctx_tname;
5717
5718 t = btf_type_by_id(btf, t->type);
5719
5720 /* KPROBE programs allow bpf_user_pt_regs_t typedef, which we need to
5721 * check before we skip all the typedef below.
5722 */
5723 if (prog_type == BPF_PROG_TYPE_KPROBE) {
5724 while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
5725 t = btf_type_by_id(btf, t->type);
5726
5727 if (btf_type_is_typedef(t)) {
5728 tname = btf_name_by_offset(btf, t->name_off);
5729 if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
5730 return true;
5731 }
5732 }
5733
5734 while (btf_type_is_modifier(t))
5735 t = btf_type_by_id(btf, t->type);
5736 if (!btf_type_is_struct(t)) {
5737 /* Only pointer to struct is supported for now.
5738 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5739 * is not supported yet.
5740 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5741 */
5742 return false;
5743 }
5744 tname = btf_name_by_offset(btf, t->name_off);
5745 if (!tname) {
5746 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5747 return false;
5748 }
5749
5750 ctx_type = find_canonical_prog_ctx_type(prog_type);
5751 if (!ctx_type) {
5752 bpf_log(log, "btf_vmlinux is malformed\n");
5753 /* should not happen */
5754 return false;
5755 }
5756again:
5757 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5758 if (!ctx_tname) {
5759 /* should not happen */
5760 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
5761 return false;
5762 }
5763 /* program types without named context types work only with arg:ctx tag */
5764 if (ctx_tname[0] == '\0')
5765 return false;
5766 /* only compare that prog's ctx type name is the same as
5767 * kernel expects. No need to compare field by field.
5768 * It's ok for bpf prog to do:
5769 * struct __sk_buff {};
5770 * int socket_filter_bpf_prog(struct __sk_buff *skb)
5771 * { // no fields of skb are ever used }
5772 */
5773 if (strcmp(ctx_tname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0)
5774 return true;
5775 if (strcmp(ctx_tname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0)
5776 return true;
5777 if (strcmp(ctx_tname, tname)) {
5778 /* bpf_user_pt_regs_t is a typedef, so resolve it to
5779 * underlying struct and check name again
5780 */
5781 if (!btf_type_is_modifier(ctx_type))
5782 return false;
5783 while (btf_type_is_modifier(ctx_type))
5784 ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
5785 goto again;
5786 }
5787 return true;
5788}
5789
5790/* forward declarations for arch-specific underlying types of
5791 * bpf_user_pt_regs_t; this avoids the need for arch-specific #ifdef
5792 * compilation guards below for BPF_PROG_TYPE_PERF_EVENT checks, but still
5793 * works correctly with __builtin_types_compatible_p() on respective
5794 * architectures
5795 */
5796struct user_regs_struct;
5797struct user_pt_regs;
5798
5799static int btf_validate_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5800 const struct btf_type *t, int arg,
5801 enum bpf_prog_type prog_type,
5802 enum bpf_attach_type attach_type)
5803{
5804 const struct btf_type *ctx_type;
5805 const char *tname, *ctx_tname;
5806
5807 if (!btf_is_ptr(t)) {
5808 bpf_log(log, "arg#%d type isn't a pointer\n", arg);
5809 return -EINVAL;
5810 }
5811 t = btf_type_by_id(btf, t->type);
5812
5813 /* KPROBE and PERF_EVENT programs allow bpf_user_pt_regs_t typedef */
5814 if (prog_type == BPF_PROG_TYPE_KPROBE || prog_type == BPF_PROG_TYPE_PERF_EVENT) {
5815 while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
5816 t = btf_type_by_id(btf, t->type);
5817
5818 if (btf_type_is_typedef(t)) {
5819 tname = btf_name_by_offset(btf, t->name_off);
5820 if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
5821 return 0;
5822 }
5823 }
5824
5825 /* all other program types don't use typedefs for context type */
5826 while (btf_type_is_modifier(t))
5827 t = btf_type_by_id(btf, t->type);
5828
5829 /* `void *ctx __arg_ctx` is always valid */
5830 if (btf_type_is_void(t))
5831 return 0;
5832
5833 tname = btf_name_by_offset(btf, t->name_off);
5834 if (str_is_empty(tname)) {
5835 bpf_log(log, "arg#%d type doesn't have a name\n", arg);
5836 return -EINVAL;
5837 }
5838
5839 /* special cases */
5840 switch (prog_type) {
5841 case BPF_PROG_TYPE_KPROBE:
5842 if (__btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
5843 return 0;
5844 break;
5845 case BPF_PROG_TYPE_PERF_EVENT:
5846 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) &&
5847 __btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
5848 return 0;
5849 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) &&
5850 __btf_type_is_struct(t) && strcmp(tname, "user_pt_regs") == 0)
5851 return 0;
5852 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) &&
5853 __btf_type_is_struct(t) && strcmp(tname, "user_regs_struct") == 0)
5854 return 0;
5855 break;
5856 case BPF_PROG_TYPE_RAW_TRACEPOINT:
5857 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
5858 /* allow u64* as ctx */
5859 if (btf_is_int(t) && t->size == 8)
5860 return 0;
5861 break;
5862 case BPF_PROG_TYPE_TRACING:
5863 switch (attach_type) {
5864 case BPF_TRACE_RAW_TP:
5865 /* tp_btf program is TRACING, so need special case here */
5866 if (__btf_type_is_struct(t) &&
5867 strcmp(tname, "bpf_raw_tracepoint_args") == 0)
5868 return 0;
5869 /* allow u64* as ctx */
5870 if (btf_is_int(t) && t->size == 8)
5871 return 0;
5872 break;
5873 case BPF_TRACE_ITER:
5874 /* allow struct bpf_iter__xxx types only */
5875 if (__btf_type_is_struct(t) &&
5876 strncmp(tname, "bpf_iter__", sizeof("bpf_iter__") - 1) == 0)
5877 return 0;
5878 break;
5879 case BPF_TRACE_FENTRY:
5880 case BPF_TRACE_FEXIT:
5881 case BPF_MODIFY_RETURN:
5882 /* allow u64* as ctx */
5883 if (btf_is_int(t) && t->size == 8)
5884 return 0;
5885 break;
5886 default:
5887 break;
5888 }
5889 break;
5890 case BPF_PROG_TYPE_LSM:
5891 case BPF_PROG_TYPE_STRUCT_OPS:
5892 /* allow u64* as ctx */
5893 if (btf_is_int(t) && t->size == 8)
5894 return 0;
5895 break;
5896 case BPF_PROG_TYPE_TRACEPOINT:
5897 case BPF_PROG_TYPE_SYSCALL:
5898 case BPF_PROG_TYPE_EXT:
5899 return 0; /* anything goes */
5900 default:
5901 break;
5902 }
5903
5904 ctx_type = find_canonical_prog_ctx_type(prog_type);
5905 if (!ctx_type) {
5906 /* should not happen */
5907 bpf_log(log, "btf_vmlinux is malformed\n");
5908 return -EINVAL;
5909 }
5910
5911 /* resolve typedefs and check that underlying structs are matching as well */
5912 while (btf_type_is_modifier(ctx_type))
5913 ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
5914
5915 /* if program type doesn't have distinctly named struct type for
5916 * context, then __arg_ctx argument can only be `void *`, which we
5917 * already checked above
5918 */
5919 if (!__btf_type_is_struct(ctx_type)) {
5920 bpf_log(log, "arg#%d should be void pointer\n", arg);
5921 return -EINVAL;
5922 }
5923
5924 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5925 if (!__btf_type_is_struct(t) || strcmp(ctx_tname, tname) != 0) {
5926 bpf_log(log, "arg#%d should be `struct %s *`\n", arg, ctx_tname);
5927 return -EINVAL;
5928 }
5929
5930 return 0;
5931}
5932
5933static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
5934 struct btf *btf,
5935 const struct btf_type *t,
5936 enum bpf_prog_type prog_type,
5937 int arg)
5938{
5939 if (!btf_is_prog_ctx_type(log, btf, t, prog_type, arg))
5940 return -ENOENT;
5941 return find_kern_ctx_type_id(prog_type);
5942}
5943
5944int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type)
5945{
5946 const struct btf_member *kctx_member;
5947 const struct btf_type *conv_struct;
5948 const struct btf_type *kctx_type;
5949 u32 kctx_type_id;
5950
5951 conv_struct = bpf_ctx_convert.t;
5952 /* get member for kernel ctx type */
5953 kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5954 kctx_type_id = kctx_member->type;
5955 kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id);
5956 if (!btf_type_is_struct(kctx_type)) {
5957 bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id);
5958 return -EINVAL;
5959 }
5960
5961 return kctx_type_id;
5962}
5963
5964BTF_ID_LIST(bpf_ctx_convert_btf_id)
5965BTF_ID(struct, bpf_ctx_convert)
5966
5967struct btf *btf_parse_vmlinux(void)
5968{
5969 struct btf_verifier_env *env = NULL;
5970 struct bpf_verifier_log *log;
5971 struct btf *btf = NULL;
5972 int err;
5973
5974 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5975 if (!env)
5976 return ERR_PTR(-ENOMEM);
5977
5978 log = &env->log;
5979 log->level = BPF_LOG_KERNEL;
5980
5981 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5982 if (!btf) {
5983 err = -ENOMEM;
5984 goto errout;
5985 }
5986 env->btf = btf;
5987
5988 btf->data = __start_BTF;
5989 btf->data_size = __stop_BTF - __start_BTF;
5990 btf->kernel_btf = true;
5991 snprintf(btf->name, sizeof(btf->name), "vmlinux");
5992
5993 err = btf_parse_hdr(env);
5994 if (err)
5995 goto errout;
5996
5997 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5998
5999 err = btf_parse_str_sec(env);
6000 if (err)
6001 goto errout;
6002
6003 err = btf_check_all_metas(env);
6004 if (err)
6005 goto errout;
6006
6007 err = btf_check_type_tags(env, btf, 1);
6008 if (err)
6009 goto errout;
6010
6011 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
6012 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
6013
6014 refcount_set(&btf->refcnt, 1);
6015
6016 err = btf_alloc_id(btf);
6017 if (err)
6018 goto errout;
6019
6020 btf_verifier_env_free(env);
6021 return btf;
6022
6023errout:
6024 btf_verifier_env_free(env);
6025 if (btf) {
6026 kvfree(btf->types);
6027 kfree(btf);
6028 }
6029 return ERR_PTR(err);
6030}
6031
6032#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6033
6034static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
6035{
6036 struct btf_verifier_env *env = NULL;
6037 struct bpf_verifier_log *log;
6038 struct btf *btf = NULL, *base_btf;
6039 int err;
6040
6041 base_btf = bpf_get_btf_vmlinux();
6042 if (IS_ERR(base_btf))
6043 return base_btf;
6044 if (!base_btf)
6045 return ERR_PTR(-EINVAL);
6046
6047 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
6048 if (!env)
6049 return ERR_PTR(-ENOMEM);
6050
6051 log = &env->log;
6052 log->level = BPF_LOG_KERNEL;
6053
6054 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
6055 if (!btf) {
6056 err = -ENOMEM;
6057 goto errout;
6058 }
6059 env->btf = btf;
6060
6061 btf->base_btf = base_btf;
6062 btf->start_id = base_btf->nr_types;
6063 btf->start_str_off = base_btf->hdr.str_len;
6064 btf->kernel_btf = true;
6065 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
6066
6067 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
6068 if (!btf->data) {
6069 err = -ENOMEM;
6070 goto errout;
6071 }
6072 memcpy(btf->data, data, data_size);
6073 btf->data_size = data_size;
6074
6075 err = btf_parse_hdr(env);
6076 if (err)
6077 goto errout;
6078
6079 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6080
6081 err = btf_parse_str_sec(env);
6082 if (err)
6083 goto errout;
6084
6085 err = btf_check_all_metas(env);
6086 if (err)
6087 goto errout;
6088
6089 err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
6090 if (err)
6091 goto errout;
6092
6093 btf_verifier_env_free(env);
6094 refcount_set(&btf->refcnt, 1);
6095 return btf;
6096
6097errout:
6098 btf_verifier_env_free(env);
6099 if (btf) {
6100 kvfree(btf->data);
6101 kvfree(btf->types);
6102 kfree(btf);
6103 }
6104 return ERR_PTR(err);
6105}
6106
6107#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6108
6109struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
6110{
6111 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6112
6113 if (tgt_prog)
6114 return tgt_prog->aux->btf;
6115 else
6116 return prog->aux->attach_btf;
6117}
6118
6119static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
6120{
6121 /* skip modifiers */
6122 t = btf_type_skip_modifiers(btf, t->type, NULL);
6123
6124 return btf_type_is_int(t);
6125}
6126
6127static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
6128 int off)
6129{
6130 const struct btf_param *args;
6131 const struct btf_type *t;
6132 u32 offset = 0, nr_args;
6133 int i;
6134
6135 if (!func_proto)
6136 return off / 8;
6137
6138 nr_args = btf_type_vlen(func_proto);
6139 args = (const struct btf_param *)(func_proto + 1);
6140 for (i = 0; i < nr_args; i++) {
6141 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6142 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6143 if (off < offset)
6144 return i;
6145 }
6146
6147 t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
6148 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6149 if (off < offset)
6150 return nr_args;
6151
6152 return nr_args + 1;
6153}
6154
6155static bool prog_args_trusted(const struct bpf_prog *prog)
6156{
6157 enum bpf_attach_type atype = prog->expected_attach_type;
6158
6159 switch (prog->type) {
6160 case BPF_PROG_TYPE_TRACING:
6161 return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER;
6162 case BPF_PROG_TYPE_LSM:
6163 return bpf_lsm_is_trusted(prog);
6164 case BPF_PROG_TYPE_STRUCT_OPS:
6165 return true;
6166 default:
6167 return false;
6168 }
6169}
6170
6171int btf_ctx_arg_offset(const struct btf *btf, const struct btf_type *func_proto,
6172 u32 arg_no)
6173{
6174 const struct btf_param *args;
6175 const struct btf_type *t;
6176 int off = 0, i;
6177 u32 sz;
6178
6179 args = btf_params(func_proto);
6180 for (i = 0; i < arg_no; i++) {
6181 t = btf_type_by_id(btf, args[i].type);
6182 t = btf_resolve_size(btf, t, &sz);
6183 if (IS_ERR(t))
6184 return PTR_ERR(t);
6185 off += roundup(sz, 8);
6186 }
6187
6188 return off;
6189}
6190
6191bool btf_ctx_access(int off, int size, enum bpf_access_type type,
6192 const struct bpf_prog *prog,
6193 struct bpf_insn_access_aux *info)
6194{
6195 const struct btf_type *t = prog->aux->attach_func_proto;
6196 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6197 struct btf *btf = bpf_prog_get_target_btf(prog);
6198 const char *tname = prog->aux->attach_func_name;
6199 struct bpf_verifier_log *log = info->log;
6200 const struct btf_param *args;
6201 const char *tag_value;
6202 u32 nr_args, arg;
6203 int i, ret;
6204
6205 if (off % 8) {
6206 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
6207 tname, off);
6208 return false;
6209 }
6210 arg = get_ctx_arg_idx(btf, t, off);
6211 args = (const struct btf_param *)(t + 1);
6212 /* if (t == NULL) Fall back to default BPF prog with
6213 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
6214 */
6215 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
6216 if (prog->aux->attach_btf_trace) {
6217 /* skip first 'void *__data' argument in btf_trace_##name typedef */
6218 args++;
6219 nr_args--;
6220 }
6221
6222 if (arg > nr_args) {
6223 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6224 tname, arg + 1);
6225 return false;
6226 }
6227
6228 if (arg == nr_args) {
6229 switch (prog->expected_attach_type) {
6230 case BPF_LSM_CGROUP:
6231 case BPF_LSM_MAC:
6232 case BPF_TRACE_FEXIT:
6233 /* When LSM programs are attached to void LSM hooks
6234 * they use FEXIT trampolines and when attached to
6235 * int LSM hooks, they use MODIFY_RETURN trampolines.
6236 *
6237 * While the LSM programs are BPF_MODIFY_RETURN-like
6238 * the check:
6239 *
6240 * if (ret_type != 'int')
6241 * return -EINVAL;
6242 *
6243 * is _not_ done here. This is still safe as LSM hooks
6244 * have only void and int return types.
6245 */
6246 if (!t)
6247 return true;
6248 t = btf_type_by_id(btf, t->type);
6249 break;
6250 case BPF_MODIFY_RETURN:
6251 /* For now the BPF_MODIFY_RETURN can only be attached to
6252 * functions that return an int.
6253 */
6254 if (!t)
6255 return false;
6256
6257 t = btf_type_skip_modifiers(btf, t->type, NULL);
6258 if (!btf_type_is_small_int(t)) {
6259 bpf_log(log,
6260 "ret type %s not allowed for fmod_ret\n",
6261 btf_type_str(t));
6262 return false;
6263 }
6264 break;
6265 default:
6266 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6267 tname, arg + 1);
6268 return false;
6269 }
6270 } else {
6271 if (!t)
6272 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
6273 return true;
6274 t = btf_type_by_id(btf, args[arg].type);
6275 }
6276
6277 /* skip modifiers */
6278 while (btf_type_is_modifier(t))
6279 t = btf_type_by_id(btf, t->type);
6280 if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6281 /* accessing a scalar */
6282 return true;
6283 if (!btf_type_is_ptr(t)) {
6284 bpf_log(log,
6285 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
6286 tname, arg,
6287 __btf_name_by_offset(btf, t->name_off),
6288 btf_type_str(t));
6289 return false;
6290 }
6291
6292 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
6293 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6294 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6295 u32 type, flag;
6296
6297 type = base_type(ctx_arg_info->reg_type);
6298 flag = type_flag(ctx_arg_info->reg_type);
6299 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
6300 (flag & PTR_MAYBE_NULL)) {
6301 info->reg_type = ctx_arg_info->reg_type;
6302 return true;
6303 }
6304 }
6305
6306 if (t->type == 0)
6307 /* This is a pointer to void.
6308 * It is the same as scalar from the verifier safety pov.
6309 * No further pointer walking is allowed.
6310 */
6311 return true;
6312
6313 if (is_int_ptr(btf, t))
6314 return true;
6315
6316 /* this is a pointer to another type */
6317 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6318 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6319
6320 if (ctx_arg_info->offset == off) {
6321 if (!ctx_arg_info->btf_id) {
6322 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
6323 return false;
6324 }
6325
6326 info->reg_type = ctx_arg_info->reg_type;
6327 info->btf = ctx_arg_info->btf ? : btf_vmlinux;
6328 info->btf_id = ctx_arg_info->btf_id;
6329 return true;
6330 }
6331 }
6332
6333 info->reg_type = PTR_TO_BTF_ID;
6334 if (prog_args_trusted(prog))
6335 info->reg_type |= PTR_TRUSTED;
6336
6337 if (tgt_prog) {
6338 enum bpf_prog_type tgt_type;
6339
6340 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
6341 tgt_type = tgt_prog->aux->saved_dst_prog_type;
6342 else
6343 tgt_type = tgt_prog->type;
6344
6345 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
6346 if (ret > 0) {
6347 info->btf = btf_vmlinux;
6348 info->btf_id = ret;
6349 return true;
6350 } else {
6351 return false;
6352 }
6353 }
6354
6355 info->btf = btf;
6356 info->btf_id = t->type;
6357 t = btf_type_by_id(btf, t->type);
6358
6359 if (btf_type_is_type_tag(t)) {
6360 tag_value = __btf_name_by_offset(btf, t->name_off);
6361 if (strcmp(tag_value, "user") == 0)
6362 info->reg_type |= MEM_USER;
6363 if (strcmp(tag_value, "percpu") == 0)
6364 info->reg_type |= MEM_PERCPU;
6365 }
6366
6367 /* skip modifiers */
6368 while (btf_type_is_modifier(t)) {
6369 info->btf_id = t->type;
6370 t = btf_type_by_id(btf, t->type);
6371 }
6372 if (!btf_type_is_struct(t)) {
6373 bpf_log(log,
6374 "func '%s' arg%d type %s is not a struct\n",
6375 tname, arg, btf_type_str(t));
6376 return false;
6377 }
6378 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
6379 tname, arg, info->btf_id, btf_type_str(t),
6380 __btf_name_by_offset(btf, t->name_off));
6381 return true;
6382}
6383EXPORT_SYMBOL_GPL(btf_ctx_access);
6384
6385enum bpf_struct_walk_result {
6386 /* < 0 error */
6387 WALK_SCALAR = 0,
6388 WALK_PTR,
6389 WALK_STRUCT,
6390};
6391
6392static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
6393 const struct btf_type *t, int off, int size,
6394 u32 *next_btf_id, enum bpf_type_flag *flag,
6395 const char **field_name)
6396{
6397 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
6398 const struct btf_type *mtype, *elem_type = NULL;
6399 const struct btf_member *member;
6400 const char *tname, *mname, *tag_value;
6401 u32 vlen, elem_id, mid;
6402
6403again:
6404 if (btf_type_is_modifier(t))
6405 t = btf_type_skip_modifiers(btf, t->type, NULL);
6406 tname = __btf_name_by_offset(btf, t->name_off);
6407 if (!btf_type_is_struct(t)) {
6408 bpf_log(log, "Type '%s' is not a struct\n", tname);
6409 return -EINVAL;
6410 }
6411
6412 vlen = btf_type_vlen(t);
6413 if (BTF_INFO_KIND(t->info) == BTF_KIND_UNION && vlen != 1 && !(*flag & PTR_UNTRUSTED))
6414 /*
6415 * walking unions yields untrusted pointers
6416 * with exception of __bpf_md_ptr and other
6417 * unions with a single member
6418 */
6419 *flag |= PTR_UNTRUSTED;
6420
6421 if (off + size > t->size) {
6422 /* If the last element is a variable size array, we may
6423 * need to relax the rule.
6424 */
6425 struct btf_array *array_elem;
6426
6427 if (vlen == 0)
6428 goto error;
6429
6430 member = btf_type_member(t) + vlen - 1;
6431 mtype = btf_type_skip_modifiers(btf, member->type,
6432 NULL);
6433 if (!btf_type_is_array(mtype))
6434 goto error;
6435
6436 array_elem = (struct btf_array *)(mtype + 1);
6437 if (array_elem->nelems != 0)
6438 goto error;
6439
6440 moff = __btf_member_bit_offset(t, member) / 8;
6441 if (off < moff)
6442 goto error;
6443
6444 /* allow structure and integer */
6445 t = btf_type_skip_modifiers(btf, array_elem->type,
6446 NULL);
6447
6448 if (btf_type_is_int(t))
6449 return WALK_SCALAR;
6450
6451 if (!btf_type_is_struct(t))
6452 goto error;
6453
6454 off = (off - moff) % t->size;
6455 goto again;
6456
6457error:
6458 bpf_log(log, "access beyond struct %s at off %u size %u\n",
6459 tname, off, size);
6460 return -EACCES;
6461 }
6462
6463 for_each_member(i, t, member) {
6464 /* offset of the field in bytes */
6465 moff = __btf_member_bit_offset(t, member) / 8;
6466 if (off + size <= moff)
6467 /* won't find anything, field is already too far */
6468 break;
6469
6470 if (__btf_member_bitfield_size(t, member)) {
6471 u32 end_bit = __btf_member_bit_offset(t, member) +
6472 __btf_member_bitfield_size(t, member);
6473
6474 /* off <= moff instead of off == moff because clang
6475 * does not generate a BTF member for anonymous
6476 * bitfield like the ":16" here:
6477 * struct {
6478 * int :16;
6479 * int x:8;
6480 * };
6481 */
6482 if (off <= moff &&
6483 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
6484 return WALK_SCALAR;
6485
6486 /* off may be accessing a following member
6487 *
6488 * or
6489 *
6490 * Doing partial access at either end of this
6491 * bitfield. Continue on this case also to
6492 * treat it as not accessing this bitfield
6493 * and eventually error out as field not
6494 * found to keep it simple.
6495 * It could be relaxed if there was a legit
6496 * partial access case later.
6497 */
6498 continue;
6499 }
6500
6501 /* In case of "off" is pointing to holes of a struct */
6502 if (off < moff)
6503 break;
6504
6505 /* type of the field */
6506 mid = member->type;
6507 mtype = btf_type_by_id(btf, member->type);
6508 mname = __btf_name_by_offset(btf, member->name_off);
6509
6510 mtype = __btf_resolve_size(btf, mtype, &msize,
6511 &elem_type, &elem_id, &total_nelems,
6512 &mid);
6513 if (IS_ERR(mtype)) {
6514 bpf_log(log, "field %s doesn't have size\n", mname);
6515 return -EFAULT;
6516 }
6517
6518 mtrue_end = moff + msize;
6519 if (off >= mtrue_end)
6520 /* no overlap with member, keep iterating */
6521 continue;
6522
6523 if (btf_type_is_array(mtype)) {
6524 u32 elem_idx;
6525
6526 /* __btf_resolve_size() above helps to
6527 * linearize a multi-dimensional array.
6528 *
6529 * The logic here is treating an array
6530 * in a struct as the following way:
6531 *
6532 * struct outer {
6533 * struct inner array[2][2];
6534 * };
6535 *
6536 * looks like:
6537 *
6538 * struct outer {
6539 * struct inner array_elem0;
6540 * struct inner array_elem1;
6541 * struct inner array_elem2;
6542 * struct inner array_elem3;
6543 * };
6544 *
6545 * When accessing outer->array[1][0], it moves
6546 * moff to "array_elem2", set mtype to
6547 * "struct inner", and msize also becomes
6548 * sizeof(struct inner). Then most of the
6549 * remaining logic will fall through without
6550 * caring the current member is an array or
6551 * not.
6552 *
6553 * Unlike mtype/msize/moff, mtrue_end does not
6554 * change. The naming difference ("_true") tells
6555 * that it is not always corresponding to
6556 * the current mtype/msize/moff.
6557 * It is the true end of the current
6558 * member (i.e. array in this case). That
6559 * will allow an int array to be accessed like
6560 * a scratch space,
6561 * i.e. allow access beyond the size of
6562 * the array's element as long as it is
6563 * within the mtrue_end boundary.
6564 */
6565
6566 /* skip empty array */
6567 if (moff == mtrue_end)
6568 continue;
6569
6570 msize /= total_nelems;
6571 elem_idx = (off - moff) / msize;
6572 moff += elem_idx * msize;
6573 mtype = elem_type;
6574 mid = elem_id;
6575 }
6576
6577 /* the 'off' we're looking for is either equal to start
6578 * of this field or inside of this struct
6579 */
6580 if (btf_type_is_struct(mtype)) {
6581 /* our field must be inside that union or struct */
6582 t = mtype;
6583
6584 /* return if the offset matches the member offset */
6585 if (off == moff) {
6586 *next_btf_id = mid;
6587 return WALK_STRUCT;
6588 }
6589
6590 /* adjust offset we're looking for */
6591 off -= moff;
6592 goto again;
6593 }
6594
6595 if (btf_type_is_ptr(mtype)) {
6596 const struct btf_type *stype, *t;
6597 enum bpf_type_flag tmp_flag = 0;
6598 u32 id;
6599
6600 if (msize != size || off != moff) {
6601 bpf_log(log,
6602 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
6603 mname, moff, tname, off, size);
6604 return -EACCES;
6605 }
6606
6607 /* check type tag */
6608 t = btf_type_by_id(btf, mtype->type);
6609 if (btf_type_is_type_tag(t)) {
6610 tag_value = __btf_name_by_offset(btf, t->name_off);
6611 /* check __user tag */
6612 if (strcmp(tag_value, "user") == 0)
6613 tmp_flag = MEM_USER;
6614 /* check __percpu tag */
6615 if (strcmp(tag_value, "percpu") == 0)
6616 tmp_flag = MEM_PERCPU;
6617 /* check __rcu tag */
6618 if (strcmp(tag_value, "rcu") == 0)
6619 tmp_flag = MEM_RCU;
6620 }
6621
6622 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
6623 if (btf_type_is_struct(stype)) {
6624 *next_btf_id = id;
6625 *flag |= tmp_flag;
6626 if (field_name)
6627 *field_name = mname;
6628 return WALK_PTR;
6629 }
6630 }
6631
6632 /* Allow more flexible access within an int as long as
6633 * it is within mtrue_end.
6634 * Since mtrue_end could be the end of an array,
6635 * that also allows using an array of int as a scratch
6636 * space. e.g. skb->cb[].
6637 */
6638 if (off + size > mtrue_end && !(*flag & PTR_UNTRUSTED)) {
6639 bpf_log(log,
6640 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
6641 mname, mtrue_end, tname, off, size);
6642 return -EACCES;
6643 }
6644
6645 return WALK_SCALAR;
6646 }
6647 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
6648 return -EINVAL;
6649}
6650
6651int btf_struct_access(struct bpf_verifier_log *log,
6652 const struct bpf_reg_state *reg,
6653 int off, int size, enum bpf_access_type atype __maybe_unused,
6654 u32 *next_btf_id, enum bpf_type_flag *flag,
6655 const char **field_name)
6656{
6657 const struct btf *btf = reg->btf;
6658 enum bpf_type_flag tmp_flag = 0;
6659 const struct btf_type *t;
6660 u32 id = reg->btf_id;
6661 int err;
6662
6663 while (type_is_alloc(reg->type)) {
6664 struct btf_struct_meta *meta;
6665 struct btf_record *rec;
6666 int i;
6667
6668 meta = btf_find_struct_meta(btf, id);
6669 if (!meta)
6670 break;
6671 rec = meta->record;
6672 for (i = 0; i < rec->cnt; i++) {
6673 struct btf_field *field = &rec->fields[i];
6674 u32 offset = field->offset;
6675 if (off < offset + btf_field_type_size(field->type) && offset < off + size) {
6676 bpf_log(log,
6677 "direct access to %s is disallowed\n",
6678 btf_field_type_name(field->type));
6679 return -EACCES;
6680 }
6681 }
6682 break;
6683 }
6684
6685 t = btf_type_by_id(btf, id);
6686 do {
6687 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag, field_name);
6688
6689 switch (err) {
6690 case WALK_PTR:
6691 /* For local types, the destination register cannot
6692 * become a pointer again.
6693 */
6694 if (type_is_alloc(reg->type))
6695 return SCALAR_VALUE;
6696 /* If we found the pointer or scalar on t+off,
6697 * we're done.
6698 */
6699 *next_btf_id = id;
6700 *flag = tmp_flag;
6701 return PTR_TO_BTF_ID;
6702 case WALK_SCALAR:
6703 return SCALAR_VALUE;
6704 case WALK_STRUCT:
6705 /* We found nested struct, so continue the search
6706 * by diving in it. At this point the offset is
6707 * aligned with the new type, so set it to 0.
6708 */
6709 t = btf_type_by_id(btf, id);
6710 off = 0;
6711 break;
6712 default:
6713 /* It's either error or unknown return value..
6714 * scream and leave.
6715 */
6716 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
6717 return -EINVAL;
6718 return err;
6719 }
6720 } while (t);
6721
6722 return -EINVAL;
6723}
6724
6725/* Check that two BTF types, each specified as an BTF object + id, are exactly
6726 * the same. Trivial ID check is not enough due to module BTFs, because we can
6727 * end up with two different module BTFs, but IDs point to the common type in
6728 * vmlinux BTF.
6729 */
6730bool btf_types_are_same(const struct btf *btf1, u32 id1,
6731 const struct btf *btf2, u32 id2)
6732{
6733 if (id1 != id2)
6734 return false;
6735 if (btf1 == btf2)
6736 return true;
6737 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
6738}
6739
6740bool btf_struct_ids_match(struct bpf_verifier_log *log,
6741 const struct btf *btf, u32 id, int off,
6742 const struct btf *need_btf, u32 need_type_id,
6743 bool strict)
6744{
6745 const struct btf_type *type;
6746 enum bpf_type_flag flag = 0;
6747 int err;
6748
6749 /* Are we already done? */
6750 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
6751 return true;
6752 /* In case of strict type match, we do not walk struct, the top level
6753 * type match must succeed. When strict is true, off should have already
6754 * been 0.
6755 */
6756 if (strict)
6757 return false;
6758again:
6759 type = btf_type_by_id(btf, id);
6760 if (!type)
6761 return false;
6762 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag, NULL);
6763 if (err != WALK_STRUCT)
6764 return false;
6765
6766 /* We found nested struct object. If it matches
6767 * the requested ID, we're done. Otherwise let's
6768 * continue the search with offset 0 in the new
6769 * type.
6770 */
6771 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
6772 off = 0;
6773 goto again;
6774 }
6775
6776 return true;
6777}
6778
6779static int __get_type_size(struct btf *btf, u32 btf_id,
6780 const struct btf_type **ret_type)
6781{
6782 const struct btf_type *t;
6783
6784 *ret_type = btf_type_by_id(btf, 0);
6785 if (!btf_id)
6786 /* void */
6787 return 0;
6788 t = btf_type_by_id(btf, btf_id);
6789 while (t && btf_type_is_modifier(t))
6790 t = btf_type_by_id(btf, t->type);
6791 if (!t)
6792 return -EINVAL;
6793 *ret_type = t;
6794 if (btf_type_is_ptr(t))
6795 /* kernel size of pointer. Not BPF's size of pointer*/
6796 return sizeof(void *);
6797 if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6798 return t->size;
6799 return -EINVAL;
6800}
6801
6802static u8 __get_type_fmodel_flags(const struct btf_type *t)
6803{
6804 u8 flags = 0;
6805
6806 if (__btf_type_is_struct(t))
6807 flags |= BTF_FMODEL_STRUCT_ARG;
6808 if (btf_type_is_signed_int(t))
6809 flags |= BTF_FMODEL_SIGNED_ARG;
6810
6811 return flags;
6812}
6813
6814int btf_distill_func_proto(struct bpf_verifier_log *log,
6815 struct btf *btf,
6816 const struct btf_type *func,
6817 const char *tname,
6818 struct btf_func_model *m)
6819{
6820 const struct btf_param *args;
6821 const struct btf_type *t;
6822 u32 i, nargs;
6823 int ret;
6824
6825 if (!func) {
6826 /* BTF function prototype doesn't match the verifier types.
6827 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
6828 */
6829 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
6830 m->arg_size[i] = 8;
6831 m->arg_flags[i] = 0;
6832 }
6833 m->ret_size = 8;
6834 m->ret_flags = 0;
6835 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
6836 return 0;
6837 }
6838 args = (const struct btf_param *)(func + 1);
6839 nargs = btf_type_vlen(func);
6840 if (nargs > MAX_BPF_FUNC_ARGS) {
6841 bpf_log(log,
6842 "The function %s has %d arguments. Too many.\n",
6843 tname, nargs);
6844 return -EINVAL;
6845 }
6846 ret = __get_type_size(btf, func->type, &t);
6847 if (ret < 0 || __btf_type_is_struct(t)) {
6848 bpf_log(log,
6849 "The function %s return type %s is unsupported.\n",
6850 tname, btf_type_str(t));
6851 return -EINVAL;
6852 }
6853 m->ret_size = ret;
6854 m->ret_flags = __get_type_fmodel_flags(t);
6855
6856 for (i = 0; i < nargs; i++) {
6857 if (i == nargs - 1 && args[i].type == 0) {
6858 bpf_log(log,
6859 "The function %s with variable args is unsupported.\n",
6860 tname);
6861 return -EINVAL;
6862 }
6863 ret = __get_type_size(btf, args[i].type, &t);
6864
6865 /* No support of struct argument size greater than 16 bytes */
6866 if (ret < 0 || ret > 16) {
6867 bpf_log(log,
6868 "The function %s arg%d type %s is unsupported.\n",
6869 tname, i, btf_type_str(t));
6870 return -EINVAL;
6871 }
6872 if (ret == 0) {
6873 bpf_log(log,
6874 "The function %s has malformed void argument.\n",
6875 tname);
6876 return -EINVAL;
6877 }
6878 m->arg_size[i] = ret;
6879 m->arg_flags[i] = __get_type_fmodel_flags(t);
6880 }
6881 m->nr_args = nargs;
6882 return 0;
6883}
6884
6885/* Compare BTFs of two functions assuming only scalars and pointers to context.
6886 * t1 points to BTF_KIND_FUNC in btf1
6887 * t2 points to BTF_KIND_FUNC in btf2
6888 * Returns:
6889 * EINVAL - function prototype mismatch
6890 * EFAULT - verifier bug
6891 * 0 - 99% match. The last 1% is validated by the verifier.
6892 */
6893static int btf_check_func_type_match(struct bpf_verifier_log *log,
6894 struct btf *btf1, const struct btf_type *t1,
6895 struct btf *btf2, const struct btf_type *t2)
6896{
6897 const struct btf_param *args1, *args2;
6898 const char *fn1, *fn2, *s1, *s2;
6899 u32 nargs1, nargs2, i;
6900
6901 fn1 = btf_name_by_offset(btf1, t1->name_off);
6902 fn2 = btf_name_by_offset(btf2, t2->name_off);
6903
6904 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
6905 bpf_log(log, "%s() is not a global function\n", fn1);
6906 return -EINVAL;
6907 }
6908 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
6909 bpf_log(log, "%s() is not a global function\n", fn2);
6910 return -EINVAL;
6911 }
6912
6913 t1 = btf_type_by_id(btf1, t1->type);
6914 if (!t1 || !btf_type_is_func_proto(t1))
6915 return -EFAULT;
6916 t2 = btf_type_by_id(btf2, t2->type);
6917 if (!t2 || !btf_type_is_func_proto(t2))
6918 return -EFAULT;
6919
6920 args1 = (const struct btf_param *)(t1 + 1);
6921 nargs1 = btf_type_vlen(t1);
6922 args2 = (const struct btf_param *)(t2 + 1);
6923 nargs2 = btf_type_vlen(t2);
6924
6925 if (nargs1 != nargs2) {
6926 bpf_log(log, "%s() has %d args while %s() has %d args\n",
6927 fn1, nargs1, fn2, nargs2);
6928 return -EINVAL;
6929 }
6930
6931 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6932 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6933 if (t1->info != t2->info) {
6934 bpf_log(log,
6935 "Return type %s of %s() doesn't match type %s of %s()\n",
6936 btf_type_str(t1), fn1,
6937 btf_type_str(t2), fn2);
6938 return -EINVAL;
6939 }
6940
6941 for (i = 0; i < nargs1; i++) {
6942 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
6943 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
6944
6945 if (t1->info != t2->info) {
6946 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
6947 i, fn1, btf_type_str(t1),
6948 fn2, btf_type_str(t2));
6949 return -EINVAL;
6950 }
6951 if (btf_type_has_size(t1) && t1->size != t2->size) {
6952 bpf_log(log,
6953 "arg%d in %s() has size %d while %s() has %d\n",
6954 i, fn1, t1->size,
6955 fn2, t2->size);
6956 return -EINVAL;
6957 }
6958
6959 /* global functions are validated with scalars and pointers
6960 * to context only. And only global functions can be replaced.
6961 * Hence type check only those types.
6962 */
6963 if (btf_type_is_int(t1) || btf_is_any_enum(t1))
6964 continue;
6965 if (!btf_type_is_ptr(t1)) {
6966 bpf_log(log,
6967 "arg%d in %s() has unrecognized type\n",
6968 i, fn1);
6969 return -EINVAL;
6970 }
6971 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6972 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6973 if (!btf_type_is_struct(t1)) {
6974 bpf_log(log,
6975 "arg%d in %s() is not a pointer to context\n",
6976 i, fn1);
6977 return -EINVAL;
6978 }
6979 if (!btf_type_is_struct(t2)) {
6980 bpf_log(log,
6981 "arg%d in %s() is not a pointer to context\n",
6982 i, fn2);
6983 return -EINVAL;
6984 }
6985 /* This is an optional check to make program writing easier.
6986 * Compare names of structs and report an error to the user.
6987 * btf_prepare_func_args() already checked that t2 struct
6988 * is a context type. btf_prepare_func_args() will check
6989 * later that t1 struct is a context type as well.
6990 */
6991 s1 = btf_name_by_offset(btf1, t1->name_off);
6992 s2 = btf_name_by_offset(btf2, t2->name_off);
6993 if (strcmp(s1, s2)) {
6994 bpf_log(log,
6995 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
6996 i, fn1, s1, fn2, s2);
6997 return -EINVAL;
6998 }
6999 }
7000 return 0;
7001}
7002
7003/* Compare BTFs of given program with BTF of target program */
7004int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
7005 struct btf *btf2, const struct btf_type *t2)
7006{
7007 struct btf *btf1 = prog->aux->btf;
7008 const struct btf_type *t1;
7009 u32 btf_id = 0;
7010
7011 if (!prog->aux->func_info) {
7012 bpf_log(log, "Program extension requires BTF\n");
7013 return -EINVAL;
7014 }
7015
7016 btf_id = prog->aux->func_info[0].type_id;
7017 if (!btf_id)
7018 return -EFAULT;
7019
7020 t1 = btf_type_by_id(btf1, btf_id);
7021 if (!t1 || !btf_type_is_func(t1))
7022 return -EFAULT;
7023
7024 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
7025}
7026
7027static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t)
7028{
7029 const char *name;
7030
7031 t = btf_type_by_id(btf, t->type); /* skip PTR */
7032
7033 while (btf_type_is_modifier(t))
7034 t = btf_type_by_id(btf, t->type);
7035
7036 /* allow either struct or struct forward declaration */
7037 if (btf_type_is_struct(t) ||
7038 (btf_type_is_fwd(t) && btf_type_kflag(t) == 0)) {
7039 name = btf_str_by_offset(btf, t->name_off);
7040 return name && strcmp(name, "bpf_dynptr") == 0;
7041 }
7042
7043 return false;
7044}
7045
7046struct bpf_cand_cache {
7047 const char *name;
7048 u32 name_len;
7049 u16 kind;
7050 u16 cnt;
7051 struct {
7052 const struct btf *btf;
7053 u32 id;
7054 } cands[];
7055};
7056
7057static DEFINE_MUTEX(cand_cache_mutex);
7058
7059static struct bpf_cand_cache *
7060bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id);
7061
7062static int btf_get_ptr_to_btf_id(struct bpf_verifier_log *log, int arg_idx,
7063 const struct btf *btf, const struct btf_type *t)
7064{
7065 struct bpf_cand_cache *cc;
7066 struct bpf_core_ctx ctx = {
7067 .btf = btf,
7068 .log = log,
7069 };
7070 u32 kern_type_id, type_id;
7071 int err = 0;
7072
7073 /* skip PTR and modifiers */
7074 type_id = t->type;
7075 t = btf_type_by_id(btf, t->type);
7076 while (btf_type_is_modifier(t)) {
7077 type_id = t->type;
7078 t = btf_type_by_id(btf, t->type);
7079 }
7080
7081 mutex_lock(&cand_cache_mutex);
7082 cc = bpf_core_find_cands(&ctx, type_id);
7083 if (IS_ERR(cc)) {
7084 err = PTR_ERR(cc);
7085 bpf_log(log, "arg#%d reference type('%s %s') candidate matching error: %d\n",
7086 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off),
7087 err);
7088 goto cand_cache_unlock;
7089 }
7090 if (cc->cnt != 1) {
7091 bpf_log(log, "arg#%d reference type('%s %s') %s\n",
7092 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off),
7093 cc->cnt == 0 ? "has no matches" : "is ambiguous");
7094 err = cc->cnt == 0 ? -ENOENT : -ESRCH;
7095 goto cand_cache_unlock;
7096 }
7097 if (btf_is_module(cc->cands[0].btf)) {
7098 bpf_log(log, "arg#%d reference type('%s %s') points to kernel module type (unsupported)\n",
7099 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off));
7100 err = -EOPNOTSUPP;
7101 goto cand_cache_unlock;
7102 }
7103 kern_type_id = cc->cands[0].id;
7104
7105cand_cache_unlock:
7106 mutex_unlock(&cand_cache_mutex);
7107 if (err)
7108 return err;
7109
7110 return kern_type_id;
7111}
7112
7113enum btf_arg_tag {
7114 ARG_TAG_CTX = BIT_ULL(0),
7115 ARG_TAG_NONNULL = BIT_ULL(1),
7116 ARG_TAG_TRUSTED = BIT_ULL(2),
7117 ARG_TAG_NULLABLE = BIT_ULL(3),
7118 ARG_TAG_ARENA = BIT_ULL(4),
7119};
7120
7121/* Process BTF of a function to produce high-level expectation of function
7122 * arguments (like ARG_PTR_TO_CTX, or ARG_PTR_TO_MEM, etc). This information
7123 * is cached in subprog info for reuse.
7124 * Returns:
7125 * EFAULT - there is a verifier bug. Abort verification.
7126 * EINVAL - cannot convert BTF.
7127 * 0 - Successfully processed BTF and constructed argument expectations.
7128 */
7129int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
7130{
7131 bool is_global = subprog_aux(env, subprog)->linkage == BTF_FUNC_GLOBAL;
7132 struct bpf_subprog_info *sub = subprog_info(env, subprog);
7133 struct bpf_verifier_log *log = &env->log;
7134 struct bpf_prog *prog = env->prog;
7135 enum bpf_prog_type prog_type = prog->type;
7136 struct btf *btf = prog->aux->btf;
7137 const struct btf_param *args;
7138 const struct btf_type *t, *ref_t, *fn_t;
7139 u32 i, nargs, btf_id;
7140 const char *tname;
7141
7142 if (sub->args_cached)
7143 return 0;
7144
7145 if (!prog->aux->func_info) {
7146 bpf_log(log, "Verifier bug\n");
7147 return -EFAULT;
7148 }
7149
7150 btf_id = prog->aux->func_info[subprog].type_id;
7151 if (!btf_id) {
7152 if (!is_global) /* not fatal for static funcs */
7153 return -EINVAL;
7154 bpf_log(log, "Global functions need valid BTF\n");
7155 return -EFAULT;
7156 }
7157
7158 fn_t = btf_type_by_id(btf, btf_id);
7159 if (!fn_t || !btf_type_is_func(fn_t)) {
7160 /* These checks were already done by the verifier while loading
7161 * struct bpf_func_info
7162 */
7163 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
7164 subprog);
7165 return -EFAULT;
7166 }
7167 tname = btf_name_by_offset(btf, fn_t->name_off);
7168
7169 if (prog->aux->func_info_aux[subprog].unreliable) {
7170 bpf_log(log, "Verifier bug in function %s()\n", tname);
7171 return -EFAULT;
7172 }
7173 if (prog_type == BPF_PROG_TYPE_EXT)
7174 prog_type = prog->aux->dst_prog->type;
7175
7176 t = btf_type_by_id(btf, fn_t->type);
7177 if (!t || !btf_type_is_func_proto(t)) {
7178 bpf_log(log, "Invalid type of function %s()\n", tname);
7179 return -EFAULT;
7180 }
7181 args = (const struct btf_param *)(t + 1);
7182 nargs = btf_type_vlen(t);
7183 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
7184 if (!is_global)
7185 return -EINVAL;
7186 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
7187 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
7188 return -EINVAL;
7189 }
7190 /* check that function returns int, exception cb also requires this */
7191 t = btf_type_by_id(btf, t->type);
7192 while (btf_type_is_modifier(t))
7193 t = btf_type_by_id(btf, t->type);
7194 if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
7195 if (!is_global)
7196 return -EINVAL;
7197 bpf_log(log,
7198 "Global function %s() doesn't return scalar. Only those are supported.\n",
7199 tname);
7200 return -EINVAL;
7201 }
7202 /* Convert BTF function arguments into verifier types.
7203 * Only PTR_TO_CTX and SCALAR are supported atm.
7204 */
7205 for (i = 0; i < nargs; i++) {
7206 u32 tags = 0;
7207 int id = 0;
7208
7209 /* 'arg:<tag>' decl_tag takes precedence over derivation of
7210 * register type from BTF type itself
7211 */
7212 while ((id = btf_find_next_decl_tag(btf, fn_t, i, "arg:", id)) > 0) {
7213 const struct btf_type *tag_t = btf_type_by_id(btf, id);
7214 const char *tag = __btf_name_by_offset(btf, tag_t->name_off) + 4;
7215
7216 /* disallow arg tags in static subprogs */
7217 if (!is_global) {
7218 bpf_log(log, "arg#%d type tag is not supported in static functions\n", i);
7219 return -EOPNOTSUPP;
7220 }
7221
7222 if (strcmp(tag, "ctx") == 0) {
7223 tags |= ARG_TAG_CTX;
7224 } else if (strcmp(tag, "trusted") == 0) {
7225 tags |= ARG_TAG_TRUSTED;
7226 } else if (strcmp(tag, "nonnull") == 0) {
7227 tags |= ARG_TAG_NONNULL;
7228 } else if (strcmp(tag, "nullable") == 0) {
7229 tags |= ARG_TAG_NULLABLE;
7230 } else if (strcmp(tag, "arena") == 0) {
7231 tags |= ARG_TAG_ARENA;
7232 } else {
7233 bpf_log(log, "arg#%d has unsupported set of tags\n", i);
7234 return -EOPNOTSUPP;
7235 }
7236 }
7237 if (id != -ENOENT) {
7238 bpf_log(log, "arg#%d type tag fetching failure: %d\n", i, id);
7239 return id;
7240 }
7241
7242 t = btf_type_by_id(btf, args[i].type);
7243 while (btf_type_is_modifier(t))
7244 t = btf_type_by_id(btf, t->type);
7245 if (!btf_type_is_ptr(t))
7246 goto skip_pointer;
7247
7248 if ((tags & ARG_TAG_CTX) || btf_is_prog_ctx_type(log, btf, t, prog_type, i)) {
7249 if (tags & ~ARG_TAG_CTX) {
7250 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7251 return -EINVAL;
7252 }
7253 if ((tags & ARG_TAG_CTX) &&
7254 btf_validate_prog_ctx_type(log, btf, t, i, prog_type,
7255 prog->expected_attach_type))
7256 return -EINVAL;
7257 sub->args[i].arg_type = ARG_PTR_TO_CTX;
7258 continue;
7259 }
7260 if (btf_is_dynptr_ptr(btf, t)) {
7261 if (tags) {
7262 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7263 return -EINVAL;
7264 }
7265 sub->args[i].arg_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY;
7266 continue;
7267 }
7268 if (tags & ARG_TAG_TRUSTED) {
7269 int kern_type_id;
7270
7271 if (tags & ARG_TAG_NONNULL) {
7272 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7273 return -EINVAL;
7274 }
7275
7276 kern_type_id = btf_get_ptr_to_btf_id(log, i, btf, t);
7277 if (kern_type_id < 0)
7278 return kern_type_id;
7279
7280 sub->args[i].arg_type = ARG_PTR_TO_BTF_ID | PTR_TRUSTED;
7281 if (tags & ARG_TAG_NULLABLE)
7282 sub->args[i].arg_type |= PTR_MAYBE_NULL;
7283 sub->args[i].btf_id = kern_type_id;
7284 continue;
7285 }
7286 if (tags & ARG_TAG_ARENA) {
7287 if (tags & ~ARG_TAG_ARENA) {
7288 bpf_log(log, "arg#%d arena cannot be combined with any other tags\n", i);
7289 return -EINVAL;
7290 }
7291 sub->args[i].arg_type = ARG_PTR_TO_ARENA;
7292 continue;
7293 }
7294 if (is_global) { /* generic user data pointer */
7295 u32 mem_size;
7296
7297 if (tags & ARG_TAG_NULLABLE) {
7298 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7299 return -EINVAL;
7300 }
7301
7302 t = btf_type_skip_modifiers(btf, t->type, NULL);
7303 ref_t = btf_resolve_size(btf, t, &mem_size);
7304 if (IS_ERR(ref_t)) {
7305 bpf_log(log, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
7306 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
7307 PTR_ERR(ref_t));
7308 return -EINVAL;
7309 }
7310
7311 sub->args[i].arg_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL;
7312 if (tags & ARG_TAG_NONNULL)
7313 sub->args[i].arg_type &= ~PTR_MAYBE_NULL;
7314 sub->args[i].mem_size = mem_size;
7315 continue;
7316 }
7317
7318skip_pointer:
7319 if (tags) {
7320 bpf_log(log, "arg#%d has pointer tag, but is not a pointer type\n", i);
7321 return -EINVAL;
7322 }
7323 if (btf_type_is_int(t) || btf_is_any_enum(t)) {
7324 sub->args[i].arg_type = ARG_ANYTHING;
7325 continue;
7326 }
7327 if (!is_global)
7328 return -EINVAL;
7329 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
7330 i, btf_type_str(t), tname);
7331 return -EINVAL;
7332 }
7333
7334 sub->arg_cnt = nargs;
7335 sub->args_cached = true;
7336
7337 return 0;
7338}
7339
7340static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
7341 struct btf_show *show)
7342{
7343 const struct btf_type *t = btf_type_by_id(btf, type_id);
7344
7345 show->btf = btf;
7346 memset(&show->state, 0, sizeof(show->state));
7347 memset(&show->obj, 0, sizeof(show->obj));
7348
7349 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
7350}
7351
7352static void btf_seq_show(struct btf_show *show, const char *fmt,
7353 va_list args)
7354{
7355 seq_vprintf((struct seq_file *)show->target, fmt, args);
7356}
7357
7358int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
7359 void *obj, struct seq_file *m, u64 flags)
7360{
7361 struct btf_show sseq;
7362
7363 sseq.target = m;
7364 sseq.showfn = btf_seq_show;
7365 sseq.flags = flags;
7366
7367 btf_type_show(btf, type_id, obj, &sseq);
7368
7369 return sseq.state.status;
7370}
7371
7372void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
7373 struct seq_file *m)
7374{
7375 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
7376 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
7377 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
7378}
7379
7380struct btf_show_snprintf {
7381 struct btf_show show;
7382 int len_left; /* space left in string */
7383 int len; /* length we would have written */
7384};
7385
7386static void btf_snprintf_show(struct btf_show *show, const char *fmt,
7387 va_list args)
7388{
7389 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
7390 int len;
7391
7392 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
7393
7394 if (len < 0) {
7395 ssnprintf->len_left = 0;
7396 ssnprintf->len = len;
7397 } else if (len >= ssnprintf->len_left) {
7398 /* no space, drive on to get length we would have written */
7399 ssnprintf->len_left = 0;
7400 ssnprintf->len += len;
7401 } else {
7402 ssnprintf->len_left -= len;
7403 ssnprintf->len += len;
7404 show->target += len;
7405 }
7406}
7407
7408int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
7409 char *buf, int len, u64 flags)
7410{
7411 struct btf_show_snprintf ssnprintf;
7412
7413 ssnprintf.show.target = buf;
7414 ssnprintf.show.flags = flags;
7415 ssnprintf.show.showfn = btf_snprintf_show;
7416 ssnprintf.len_left = len;
7417 ssnprintf.len = 0;
7418
7419 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
7420
7421 /* If we encountered an error, return it. */
7422 if (ssnprintf.show.state.status)
7423 return ssnprintf.show.state.status;
7424
7425 /* Otherwise return length we would have written */
7426 return ssnprintf.len;
7427}
7428
7429#ifdef CONFIG_PROC_FS
7430static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
7431{
7432 const struct btf *btf = filp->private_data;
7433
7434 seq_printf(m, "btf_id:\t%u\n", btf->id);
7435}
7436#endif
7437
7438static int btf_release(struct inode *inode, struct file *filp)
7439{
7440 btf_put(filp->private_data);
7441 return 0;
7442}
7443
7444const struct file_operations btf_fops = {
7445#ifdef CONFIG_PROC_FS
7446 .show_fdinfo = bpf_btf_show_fdinfo,
7447#endif
7448 .release = btf_release,
7449};
7450
7451static int __btf_new_fd(struct btf *btf)
7452{
7453 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
7454}
7455
7456int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
7457{
7458 struct btf *btf;
7459 int ret;
7460
7461 btf = btf_parse(attr, uattr, uattr_size);
7462 if (IS_ERR(btf))
7463 return PTR_ERR(btf);
7464
7465 ret = btf_alloc_id(btf);
7466 if (ret) {
7467 btf_free(btf);
7468 return ret;
7469 }
7470
7471 /*
7472 * The BTF ID is published to the userspace.
7473 * All BTF free must go through call_rcu() from
7474 * now on (i.e. free by calling btf_put()).
7475 */
7476
7477 ret = __btf_new_fd(btf);
7478 if (ret < 0)
7479 btf_put(btf);
7480
7481 return ret;
7482}
7483
7484struct btf *btf_get_by_fd(int fd)
7485{
7486 struct btf *btf;
7487 struct fd f;
7488
7489 f = fdget(fd);
7490
7491 if (!f.file)
7492 return ERR_PTR(-EBADF);
7493
7494 if (f.file->f_op != &btf_fops) {
7495 fdput(f);
7496 return ERR_PTR(-EINVAL);
7497 }
7498
7499 btf = f.file->private_data;
7500 refcount_inc(&btf->refcnt);
7501 fdput(f);
7502
7503 return btf;
7504}
7505
7506int btf_get_info_by_fd(const struct btf *btf,
7507 const union bpf_attr *attr,
7508 union bpf_attr __user *uattr)
7509{
7510 struct bpf_btf_info __user *uinfo;
7511 struct bpf_btf_info info;
7512 u32 info_copy, btf_copy;
7513 void __user *ubtf;
7514 char __user *uname;
7515 u32 uinfo_len, uname_len, name_len;
7516 int ret = 0;
7517
7518 uinfo = u64_to_user_ptr(attr->info.info);
7519 uinfo_len = attr->info.info_len;
7520
7521 info_copy = min_t(u32, uinfo_len, sizeof(info));
7522 memset(&info, 0, sizeof(info));
7523 if (copy_from_user(&info, uinfo, info_copy))
7524 return -EFAULT;
7525
7526 info.id = btf->id;
7527 ubtf = u64_to_user_ptr(info.btf);
7528 btf_copy = min_t(u32, btf->data_size, info.btf_size);
7529 if (copy_to_user(ubtf, btf->data, btf_copy))
7530 return -EFAULT;
7531 info.btf_size = btf->data_size;
7532
7533 info.kernel_btf = btf->kernel_btf;
7534
7535 uname = u64_to_user_ptr(info.name);
7536 uname_len = info.name_len;
7537 if (!uname ^ !uname_len)
7538 return -EINVAL;
7539
7540 name_len = strlen(btf->name);
7541 info.name_len = name_len;
7542
7543 if (uname) {
7544 if (uname_len >= name_len + 1) {
7545 if (copy_to_user(uname, btf->name, name_len + 1))
7546 return -EFAULT;
7547 } else {
7548 char zero = '\0';
7549
7550 if (copy_to_user(uname, btf->name, uname_len - 1))
7551 return -EFAULT;
7552 if (put_user(zero, uname + uname_len - 1))
7553 return -EFAULT;
7554 /* let user-space know about too short buffer */
7555 ret = -ENOSPC;
7556 }
7557 }
7558
7559 if (copy_to_user(uinfo, &info, info_copy) ||
7560 put_user(info_copy, &uattr->info.info_len))
7561 return -EFAULT;
7562
7563 return ret;
7564}
7565
7566int btf_get_fd_by_id(u32 id)
7567{
7568 struct btf *btf;
7569 int fd;
7570
7571 rcu_read_lock();
7572 btf = idr_find(&btf_idr, id);
7573 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
7574 btf = ERR_PTR(-ENOENT);
7575 rcu_read_unlock();
7576
7577 if (IS_ERR(btf))
7578 return PTR_ERR(btf);
7579
7580 fd = __btf_new_fd(btf);
7581 if (fd < 0)
7582 btf_put(btf);
7583
7584 return fd;
7585}
7586
7587u32 btf_obj_id(const struct btf *btf)
7588{
7589 return btf->id;
7590}
7591
7592bool btf_is_kernel(const struct btf *btf)
7593{
7594 return btf->kernel_btf;
7595}
7596
7597bool btf_is_module(const struct btf *btf)
7598{
7599 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
7600}
7601
7602enum {
7603 BTF_MODULE_F_LIVE = (1 << 0),
7604};
7605
7606#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7607struct btf_module {
7608 struct list_head list;
7609 struct module *module;
7610 struct btf *btf;
7611 struct bin_attribute *sysfs_attr;
7612 int flags;
7613};
7614
7615static LIST_HEAD(btf_modules);
7616static DEFINE_MUTEX(btf_module_mutex);
7617
7618static ssize_t
7619btf_module_read(struct file *file, struct kobject *kobj,
7620 struct bin_attribute *bin_attr,
7621 char *buf, loff_t off, size_t len)
7622{
7623 const struct btf *btf = bin_attr->private;
7624
7625 memcpy(buf, btf->data + off, len);
7626 return len;
7627}
7628
7629static void purge_cand_cache(struct btf *btf);
7630
7631static int btf_module_notify(struct notifier_block *nb, unsigned long op,
7632 void *module)
7633{
7634 struct btf_module *btf_mod, *tmp;
7635 struct module *mod = module;
7636 struct btf *btf;
7637 int err = 0;
7638
7639 if (mod->btf_data_size == 0 ||
7640 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
7641 op != MODULE_STATE_GOING))
7642 goto out;
7643
7644 switch (op) {
7645 case MODULE_STATE_COMING:
7646 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
7647 if (!btf_mod) {
7648 err = -ENOMEM;
7649 goto out;
7650 }
7651 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
7652 if (IS_ERR(btf)) {
7653 kfree(btf_mod);
7654 if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH)) {
7655 pr_warn("failed to validate module [%s] BTF: %ld\n",
7656 mod->name, PTR_ERR(btf));
7657 err = PTR_ERR(btf);
7658 } else {
7659 pr_warn_once("Kernel module BTF mismatch detected, BTF debug info may be unavailable for some modules\n");
7660 }
7661 goto out;
7662 }
7663 err = btf_alloc_id(btf);
7664 if (err) {
7665 btf_free(btf);
7666 kfree(btf_mod);
7667 goto out;
7668 }
7669
7670 purge_cand_cache(NULL);
7671 mutex_lock(&btf_module_mutex);
7672 btf_mod->module = module;
7673 btf_mod->btf = btf;
7674 list_add(&btf_mod->list, &btf_modules);
7675 mutex_unlock(&btf_module_mutex);
7676
7677 if (IS_ENABLED(CONFIG_SYSFS)) {
7678 struct bin_attribute *attr;
7679
7680 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
7681 if (!attr)
7682 goto out;
7683
7684 sysfs_bin_attr_init(attr);
7685 attr->attr.name = btf->name;
7686 attr->attr.mode = 0444;
7687 attr->size = btf->data_size;
7688 attr->private = btf;
7689 attr->read = btf_module_read;
7690
7691 err = sysfs_create_bin_file(btf_kobj, attr);
7692 if (err) {
7693 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
7694 mod->name, err);
7695 kfree(attr);
7696 err = 0;
7697 goto out;
7698 }
7699
7700 btf_mod->sysfs_attr = attr;
7701 }
7702
7703 break;
7704 case MODULE_STATE_LIVE:
7705 mutex_lock(&btf_module_mutex);
7706 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7707 if (btf_mod->module != module)
7708 continue;
7709
7710 btf_mod->flags |= BTF_MODULE_F_LIVE;
7711 break;
7712 }
7713 mutex_unlock(&btf_module_mutex);
7714 break;
7715 case MODULE_STATE_GOING:
7716 mutex_lock(&btf_module_mutex);
7717 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7718 if (btf_mod->module != module)
7719 continue;
7720
7721 list_del(&btf_mod->list);
7722 if (btf_mod->sysfs_attr)
7723 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
7724 purge_cand_cache(btf_mod->btf);
7725 btf_put(btf_mod->btf);
7726 kfree(btf_mod->sysfs_attr);
7727 kfree(btf_mod);
7728 break;
7729 }
7730 mutex_unlock(&btf_module_mutex);
7731 break;
7732 }
7733out:
7734 return notifier_from_errno(err);
7735}
7736
7737static struct notifier_block btf_module_nb = {
7738 .notifier_call = btf_module_notify,
7739};
7740
7741static int __init btf_module_init(void)
7742{
7743 register_module_notifier(&btf_module_nb);
7744 return 0;
7745}
7746
7747fs_initcall(btf_module_init);
7748#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
7749
7750struct module *btf_try_get_module(const struct btf *btf)
7751{
7752 struct module *res = NULL;
7753#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7754 struct btf_module *btf_mod, *tmp;
7755
7756 mutex_lock(&btf_module_mutex);
7757 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7758 if (btf_mod->btf != btf)
7759 continue;
7760
7761 /* We must only consider module whose __init routine has
7762 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
7763 * which is set from the notifier callback for
7764 * MODULE_STATE_LIVE.
7765 */
7766 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
7767 res = btf_mod->module;
7768
7769 break;
7770 }
7771 mutex_unlock(&btf_module_mutex);
7772#endif
7773
7774 return res;
7775}
7776
7777/* Returns struct btf corresponding to the struct module.
7778 * This function can return NULL or ERR_PTR.
7779 */
7780static struct btf *btf_get_module_btf(const struct module *module)
7781{
7782#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7783 struct btf_module *btf_mod, *tmp;
7784#endif
7785 struct btf *btf = NULL;
7786
7787 if (!module) {
7788 btf = bpf_get_btf_vmlinux();
7789 if (!IS_ERR_OR_NULL(btf))
7790 btf_get(btf);
7791 return btf;
7792 }
7793
7794#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7795 mutex_lock(&btf_module_mutex);
7796 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7797 if (btf_mod->module != module)
7798 continue;
7799
7800 btf_get(btf_mod->btf);
7801 btf = btf_mod->btf;
7802 break;
7803 }
7804 mutex_unlock(&btf_module_mutex);
7805#endif
7806
7807 return btf;
7808}
7809
7810static int check_btf_kconfigs(const struct module *module, const char *feature)
7811{
7812 if (!module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7813 pr_err("missing vmlinux BTF, cannot register %s\n", feature);
7814 return -ENOENT;
7815 }
7816 if (module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
7817 pr_warn("missing module BTF, cannot register %s\n", feature);
7818 return 0;
7819}
7820
7821BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
7822{
7823 struct btf *btf = NULL;
7824 int btf_obj_fd = 0;
7825 long ret;
7826
7827 if (flags)
7828 return -EINVAL;
7829
7830 if (name_sz <= 1 || name[name_sz - 1])
7831 return -EINVAL;
7832
7833 ret = bpf_find_btf_id(name, kind, &btf);
7834 if (ret > 0 && btf_is_module(btf)) {
7835 btf_obj_fd = __btf_new_fd(btf);
7836 if (btf_obj_fd < 0) {
7837 btf_put(btf);
7838 return btf_obj_fd;
7839 }
7840 return ret | (((u64)btf_obj_fd) << 32);
7841 }
7842 if (ret > 0)
7843 btf_put(btf);
7844 return ret;
7845}
7846
7847const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
7848 .func = bpf_btf_find_by_name_kind,
7849 .gpl_only = false,
7850 .ret_type = RET_INTEGER,
7851 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
7852 .arg2_type = ARG_CONST_SIZE,
7853 .arg3_type = ARG_ANYTHING,
7854 .arg4_type = ARG_ANYTHING,
7855};
7856
7857BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
7858#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
7859BTF_TRACING_TYPE_xxx
7860#undef BTF_TRACING_TYPE
7861
7862static int btf_check_iter_kfuncs(struct btf *btf, const char *func_name,
7863 const struct btf_type *func, u32 func_flags)
7864{
7865 u32 flags = func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
7866 const char *name, *sfx, *iter_name;
7867 const struct btf_param *arg;
7868 const struct btf_type *t;
7869 char exp_name[128];
7870 u32 nr_args;
7871
7872 /* exactly one of KF_ITER_{NEW,NEXT,DESTROY} can be set */
7873 if (!flags || (flags & (flags - 1)))
7874 return -EINVAL;
7875
7876 /* any BPF iter kfunc should have `struct bpf_iter_<type> *` first arg */
7877 nr_args = btf_type_vlen(func);
7878 if (nr_args < 1)
7879 return -EINVAL;
7880
7881 arg = &btf_params(func)[0];
7882 t = btf_type_skip_modifiers(btf, arg->type, NULL);
7883 if (!t || !btf_type_is_ptr(t))
7884 return -EINVAL;
7885 t = btf_type_skip_modifiers(btf, t->type, NULL);
7886 if (!t || !__btf_type_is_struct(t))
7887 return -EINVAL;
7888
7889 name = btf_name_by_offset(btf, t->name_off);
7890 if (!name || strncmp(name, ITER_PREFIX, sizeof(ITER_PREFIX) - 1))
7891 return -EINVAL;
7892
7893 /* sizeof(struct bpf_iter_<type>) should be a multiple of 8 to
7894 * fit nicely in stack slots
7895 */
7896 if (t->size == 0 || (t->size % 8))
7897 return -EINVAL;
7898
7899 /* validate bpf_iter_<type>_{new,next,destroy}(struct bpf_iter_<type> *)
7900 * naming pattern
7901 */
7902 iter_name = name + sizeof(ITER_PREFIX) - 1;
7903 if (flags & KF_ITER_NEW)
7904 sfx = "new";
7905 else if (flags & KF_ITER_NEXT)
7906 sfx = "next";
7907 else /* (flags & KF_ITER_DESTROY) */
7908 sfx = "destroy";
7909
7910 snprintf(exp_name, sizeof(exp_name), "bpf_iter_%s_%s", iter_name, sfx);
7911 if (strcmp(func_name, exp_name))
7912 return -EINVAL;
7913
7914 /* only iter constructor should have extra arguments */
7915 if (!(flags & KF_ITER_NEW) && nr_args != 1)
7916 return -EINVAL;
7917
7918 if (flags & KF_ITER_NEXT) {
7919 /* bpf_iter_<type>_next() should return pointer */
7920 t = btf_type_skip_modifiers(btf, func->type, NULL);
7921 if (!t || !btf_type_is_ptr(t))
7922 return -EINVAL;
7923 }
7924
7925 if (flags & KF_ITER_DESTROY) {
7926 /* bpf_iter_<type>_destroy() should return void */
7927 t = btf_type_by_id(btf, func->type);
7928 if (!t || !btf_type_is_void(t))
7929 return -EINVAL;
7930 }
7931
7932 return 0;
7933}
7934
7935static int btf_check_kfunc_protos(struct btf *btf, u32 func_id, u32 func_flags)
7936{
7937 const struct btf_type *func;
7938 const char *func_name;
7939 int err;
7940
7941 /* any kfunc should be FUNC -> FUNC_PROTO */
7942 func = btf_type_by_id(btf, func_id);
7943 if (!func || !btf_type_is_func(func))
7944 return -EINVAL;
7945
7946 /* sanity check kfunc name */
7947 func_name = btf_name_by_offset(btf, func->name_off);
7948 if (!func_name || !func_name[0])
7949 return -EINVAL;
7950
7951 func = btf_type_by_id(btf, func->type);
7952 if (!func || !btf_type_is_func_proto(func))
7953 return -EINVAL;
7954
7955 if (func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY)) {
7956 err = btf_check_iter_kfuncs(btf, func_name, func, func_flags);
7957 if (err)
7958 return err;
7959 }
7960
7961 return 0;
7962}
7963
7964/* Kernel Function (kfunc) BTF ID set registration API */
7965
7966static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
7967 const struct btf_kfunc_id_set *kset)
7968{
7969 struct btf_kfunc_hook_filter *hook_filter;
7970 struct btf_id_set8 *add_set = kset->set;
7971 bool vmlinux_set = !btf_is_module(btf);
7972 bool add_filter = !!kset->filter;
7973 struct btf_kfunc_set_tab *tab;
7974 struct btf_id_set8 *set;
7975 u32 set_cnt;
7976 int ret;
7977
7978 if (hook >= BTF_KFUNC_HOOK_MAX) {
7979 ret = -EINVAL;
7980 goto end;
7981 }
7982
7983 if (!add_set->cnt)
7984 return 0;
7985
7986 tab = btf->kfunc_set_tab;
7987
7988 if (tab && add_filter) {
7989 u32 i;
7990
7991 hook_filter = &tab->hook_filters[hook];
7992 for (i = 0; i < hook_filter->nr_filters; i++) {
7993 if (hook_filter->filters[i] == kset->filter) {
7994 add_filter = false;
7995 break;
7996 }
7997 }
7998
7999 if (add_filter && hook_filter->nr_filters == BTF_KFUNC_FILTER_MAX_CNT) {
8000 ret = -E2BIG;
8001 goto end;
8002 }
8003 }
8004
8005 if (!tab) {
8006 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
8007 if (!tab)
8008 return -ENOMEM;
8009 btf->kfunc_set_tab = tab;
8010 }
8011
8012 set = tab->sets[hook];
8013 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
8014 * for module sets.
8015 */
8016 if (WARN_ON_ONCE(set && !vmlinux_set)) {
8017 ret = -EINVAL;
8018 goto end;
8019 }
8020
8021 /* We don't need to allocate, concatenate, and sort module sets, because
8022 * only one is allowed per hook. Hence, we can directly assign the
8023 * pointer and return.
8024 */
8025 if (!vmlinux_set) {
8026 tab->sets[hook] = add_set;
8027 goto do_add_filter;
8028 }
8029
8030 /* In case of vmlinux sets, there may be more than one set being
8031 * registered per hook. To create a unified set, we allocate a new set
8032 * and concatenate all individual sets being registered. While each set
8033 * is individually sorted, they may become unsorted when concatenated,
8034 * hence re-sorting the final set again is required to make binary
8035 * searching the set using btf_id_set8_contains function work.
8036 */
8037 set_cnt = set ? set->cnt : 0;
8038
8039 if (set_cnt > U32_MAX - add_set->cnt) {
8040 ret = -EOVERFLOW;
8041 goto end;
8042 }
8043
8044 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
8045 ret = -E2BIG;
8046 goto end;
8047 }
8048
8049 /* Grow set */
8050 set = krealloc(tab->sets[hook],
8051 offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
8052 GFP_KERNEL | __GFP_NOWARN);
8053 if (!set) {
8054 ret = -ENOMEM;
8055 goto end;
8056 }
8057
8058 /* For newly allocated set, initialize set->cnt to 0 */
8059 if (!tab->sets[hook])
8060 set->cnt = 0;
8061 tab->sets[hook] = set;
8062
8063 /* Concatenate the two sets */
8064 memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
8065 set->cnt += add_set->cnt;
8066
8067 sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
8068
8069do_add_filter:
8070 if (add_filter) {
8071 hook_filter = &tab->hook_filters[hook];
8072 hook_filter->filters[hook_filter->nr_filters++] = kset->filter;
8073 }
8074 return 0;
8075end:
8076 btf_free_kfunc_set_tab(btf);
8077 return ret;
8078}
8079
8080static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
8081 enum btf_kfunc_hook hook,
8082 u32 kfunc_btf_id,
8083 const struct bpf_prog *prog)
8084{
8085 struct btf_kfunc_hook_filter *hook_filter;
8086 struct btf_id_set8 *set;
8087 u32 *id, i;
8088
8089 if (hook >= BTF_KFUNC_HOOK_MAX)
8090 return NULL;
8091 if (!btf->kfunc_set_tab)
8092 return NULL;
8093 hook_filter = &btf->kfunc_set_tab->hook_filters[hook];
8094 for (i = 0; i < hook_filter->nr_filters; i++) {
8095 if (hook_filter->filters[i](prog, kfunc_btf_id))
8096 return NULL;
8097 }
8098 set = btf->kfunc_set_tab->sets[hook];
8099 if (!set)
8100 return NULL;
8101 id = btf_id_set8_contains(set, kfunc_btf_id);
8102 if (!id)
8103 return NULL;
8104 /* The flags for BTF ID are located next to it */
8105 return id + 1;
8106}
8107
8108static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
8109{
8110 switch (prog_type) {
8111 case BPF_PROG_TYPE_UNSPEC:
8112 return BTF_KFUNC_HOOK_COMMON;
8113 case BPF_PROG_TYPE_XDP:
8114 return BTF_KFUNC_HOOK_XDP;
8115 case BPF_PROG_TYPE_SCHED_CLS:
8116 return BTF_KFUNC_HOOK_TC;
8117 case BPF_PROG_TYPE_STRUCT_OPS:
8118 return BTF_KFUNC_HOOK_STRUCT_OPS;
8119 case BPF_PROG_TYPE_TRACING:
8120 case BPF_PROG_TYPE_LSM:
8121 return BTF_KFUNC_HOOK_TRACING;
8122 case BPF_PROG_TYPE_SYSCALL:
8123 return BTF_KFUNC_HOOK_SYSCALL;
8124 case BPF_PROG_TYPE_CGROUP_SKB:
8125 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
8126 return BTF_KFUNC_HOOK_CGROUP_SKB;
8127 case BPF_PROG_TYPE_SCHED_ACT:
8128 return BTF_KFUNC_HOOK_SCHED_ACT;
8129 case BPF_PROG_TYPE_SK_SKB:
8130 return BTF_KFUNC_HOOK_SK_SKB;
8131 case BPF_PROG_TYPE_SOCKET_FILTER:
8132 return BTF_KFUNC_HOOK_SOCKET_FILTER;
8133 case BPF_PROG_TYPE_LWT_OUT:
8134 case BPF_PROG_TYPE_LWT_IN:
8135 case BPF_PROG_TYPE_LWT_XMIT:
8136 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
8137 return BTF_KFUNC_HOOK_LWT;
8138 case BPF_PROG_TYPE_NETFILTER:
8139 return BTF_KFUNC_HOOK_NETFILTER;
8140 default:
8141 return BTF_KFUNC_HOOK_MAX;
8142 }
8143}
8144
8145/* Caution:
8146 * Reference to the module (obtained using btf_try_get_module) corresponding to
8147 * the struct btf *MUST* be held when calling this function from verifier
8148 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
8149 * keeping the reference for the duration of the call provides the necessary
8150 * protection for looking up a well-formed btf->kfunc_set_tab.
8151 */
8152u32 *btf_kfunc_id_set_contains(const struct btf *btf,
8153 u32 kfunc_btf_id,
8154 const struct bpf_prog *prog)
8155{
8156 enum bpf_prog_type prog_type = resolve_prog_type(prog);
8157 enum btf_kfunc_hook hook;
8158 u32 *kfunc_flags;
8159
8160 kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id, prog);
8161 if (kfunc_flags)
8162 return kfunc_flags;
8163
8164 hook = bpf_prog_type_to_kfunc_hook(prog_type);
8165 return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id, prog);
8166}
8167
8168u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
8169 const struct bpf_prog *prog)
8170{
8171 return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id, prog);
8172}
8173
8174static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
8175 const struct btf_kfunc_id_set *kset)
8176{
8177 struct btf *btf;
8178 int ret, i;
8179
8180 btf = btf_get_module_btf(kset->owner);
8181 if (!btf)
8182 return check_btf_kconfigs(kset->owner, "kfunc");
8183 if (IS_ERR(btf))
8184 return PTR_ERR(btf);
8185
8186 for (i = 0; i < kset->set->cnt; i++) {
8187 ret = btf_check_kfunc_protos(btf, kset->set->pairs[i].id,
8188 kset->set->pairs[i].flags);
8189 if (ret)
8190 goto err_out;
8191 }
8192
8193 ret = btf_populate_kfunc_set(btf, hook, kset);
8194
8195err_out:
8196 btf_put(btf);
8197 return ret;
8198}
8199
8200/* This function must be invoked only from initcalls/module init functions */
8201int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
8202 const struct btf_kfunc_id_set *kset)
8203{
8204 enum btf_kfunc_hook hook;
8205
8206 /* All kfuncs need to be tagged as such in BTF.
8207 * WARN() for initcall registrations that do not check errors.
8208 */
8209 if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
8210 WARN_ON(!kset->owner);
8211 return -EINVAL;
8212 }
8213
8214 hook = bpf_prog_type_to_kfunc_hook(prog_type);
8215 return __register_btf_kfunc_id_set(hook, kset);
8216}
8217EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
8218
8219/* This function must be invoked only from initcalls/module init functions */
8220int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset)
8221{
8222 return __register_btf_kfunc_id_set(BTF_KFUNC_HOOK_FMODRET, kset);
8223}
8224EXPORT_SYMBOL_GPL(register_btf_fmodret_id_set);
8225
8226s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
8227{
8228 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
8229 struct btf_id_dtor_kfunc *dtor;
8230
8231 if (!tab)
8232 return -ENOENT;
8233 /* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
8234 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
8235 */
8236 BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
8237 dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
8238 if (!dtor)
8239 return -ENOENT;
8240 return dtor->kfunc_btf_id;
8241}
8242
8243static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
8244{
8245 const struct btf_type *dtor_func, *dtor_func_proto, *t;
8246 const struct btf_param *args;
8247 s32 dtor_btf_id;
8248 u32 nr_args, i;
8249
8250 for (i = 0; i < cnt; i++) {
8251 dtor_btf_id = dtors[i].kfunc_btf_id;
8252
8253 dtor_func = btf_type_by_id(btf, dtor_btf_id);
8254 if (!dtor_func || !btf_type_is_func(dtor_func))
8255 return -EINVAL;
8256
8257 dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
8258 if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
8259 return -EINVAL;
8260
8261 /* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
8262 t = btf_type_by_id(btf, dtor_func_proto->type);
8263 if (!t || !btf_type_is_void(t))
8264 return -EINVAL;
8265
8266 nr_args = btf_type_vlen(dtor_func_proto);
8267 if (nr_args != 1)
8268 return -EINVAL;
8269 args = btf_params(dtor_func_proto);
8270 t = btf_type_by_id(btf, args[0].type);
8271 /* Allow any pointer type, as width on targets Linux supports
8272 * will be same for all pointer types (i.e. sizeof(void *))
8273 */
8274 if (!t || !btf_type_is_ptr(t))
8275 return -EINVAL;
8276 }
8277 return 0;
8278}
8279
8280/* This function must be invoked only from initcalls/module init functions */
8281int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
8282 struct module *owner)
8283{
8284 struct btf_id_dtor_kfunc_tab *tab;
8285 struct btf *btf;
8286 u32 tab_cnt;
8287 int ret;
8288
8289 btf = btf_get_module_btf(owner);
8290 if (!btf)
8291 return check_btf_kconfigs(owner, "dtor kfuncs");
8292 if (IS_ERR(btf))
8293 return PTR_ERR(btf);
8294
8295 if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8296 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8297 ret = -E2BIG;
8298 goto end;
8299 }
8300
8301 /* Ensure that the prototype of dtor kfuncs being registered is sane */
8302 ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
8303 if (ret < 0)
8304 goto end;
8305
8306 tab = btf->dtor_kfunc_tab;
8307 /* Only one call allowed for modules */
8308 if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
8309 ret = -EINVAL;
8310 goto end;
8311 }
8312
8313 tab_cnt = tab ? tab->cnt : 0;
8314 if (tab_cnt > U32_MAX - add_cnt) {
8315 ret = -EOVERFLOW;
8316 goto end;
8317 }
8318 if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8319 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8320 ret = -E2BIG;
8321 goto end;
8322 }
8323
8324 tab = krealloc(btf->dtor_kfunc_tab,
8325 offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
8326 GFP_KERNEL | __GFP_NOWARN);
8327 if (!tab) {
8328 ret = -ENOMEM;
8329 goto end;
8330 }
8331
8332 if (!btf->dtor_kfunc_tab)
8333 tab->cnt = 0;
8334 btf->dtor_kfunc_tab = tab;
8335
8336 memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
8337 tab->cnt += add_cnt;
8338
8339 sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
8340
8341end:
8342 if (ret)
8343 btf_free_dtor_kfunc_tab(btf);
8344 btf_put(btf);
8345 return ret;
8346}
8347EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
8348
8349#define MAX_TYPES_ARE_COMPAT_DEPTH 2
8350
8351/* Check local and target types for compatibility. This check is used for
8352 * type-based CO-RE relocations and follow slightly different rules than
8353 * field-based relocations. This function assumes that root types were already
8354 * checked for name match. Beyond that initial root-level name check, names
8355 * are completely ignored. Compatibility rules are as follows:
8356 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
8357 * kind should match for local and target types (i.e., STRUCT is not
8358 * compatible with UNION);
8359 * - for ENUMs/ENUM64s, the size is ignored;
8360 * - for INT, size and signedness are ignored;
8361 * - for ARRAY, dimensionality is ignored, element types are checked for
8362 * compatibility recursively;
8363 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
8364 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
8365 * - FUNC_PROTOs are compatible if they have compatible signature: same
8366 * number of input args and compatible return and argument types.
8367 * These rules are not set in stone and probably will be adjusted as we get
8368 * more experience with using BPF CO-RE relocations.
8369 */
8370int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
8371 const struct btf *targ_btf, __u32 targ_id)
8372{
8373 return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
8374 MAX_TYPES_ARE_COMPAT_DEPTH);
8375}
8376
8377#define MAX_TYPES_MATCH_DEPTH 2
8378
8379int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
8380 const struct btf *targ_btf, u32 targ_id)
8381{
8382 return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
8383 MAX_TYPES_MATCH_DEPTH);
8384}
8385
8386static bool bpf_core_is_flavor_sep(const char *s)
8387{
8388 /* check X___Y name pattern, where X and Y are not underscores */
8389 return s[0] != '_' && /* X */
8390 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
8391 s[4] != '_'; /* Y */
8392}
8393
8394size_t bpf_core_essential_name_len(const char *name)
8395{
8396 size_t n = strlen(name);
8397 int i;
8398
8399 for (i = n - 5; i >= 0; i--) {
8400 if (bpf_core_is_flavor_sep(name + i))
8401 return i + 1;
8402 }
8403 return n;
8404}
8405
8406static void bpf_free_cands(struct bpf_cand_cache *cands)
8407{
8408 if (!cands->cnt)
8409 /* empty candidate array was allocated on stack */
8410 return;
8411 kfree(cands);
8412}
8413
8414static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
8415{
8416 kfree(cands->name);
8417 kfree(cands);
8418}
8419
8420#define VMLINUX_CAND_CACHE_SIZE 31
8421static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
8422
8423#define MODULE_CAND_CACHE_SIZE 31
8424static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
8425
8426static void __print_cand_cache(struct bpf_verifier_log *log,
8427 struct bpf_cand_cache **cache,
8428 int cache_size)
8429{
8430 struct bpf_cand_cache *cc;
8431 int i, j;
8432
8433 for (i = 0; i < cache_size; i++) {
8434 cc = cache[i];
8435 if (!cc)
8436 continue;
8437 bpf_log(log, "[%d]%s(", i, cc->name);
8438 for (j = 0; j < cc->cnt; j++) {
8439 bpf_log(log, "%d", cc->cands[j].id);
8440 if (j < cc->cnt - 1)
8441 bpf_log(log, " ");
8442 }
8443 bpf_log(log, "), ");
8444 }
8445}
8446
8447static void print_cand_cache(struct bpf_verifier_log *log)
8448{
8449 mutex_lock(&cand_cache_mutex);
8450 bpf_log(log, "vmlinux_cand_cache:");
8451 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8452 bpf_log(log, "\nmodule_cand_cache:");
8453 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8454 bpf_log(log, "\n");
8455 mutex_unlock(&cand_cache_mutex);
8456}
8457
8458static u32 hash_cands(struct bpf_cand_cache *cands)
8459{
8460 return jhash(cands->name, cands->name_len, 0);
8461}
8462
8463static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
8464 struct bpf_cand_cache **cache,
8465 int cache_size)
8466{
8467 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
8468
8469 if (cc && cc->name_len == cands->name_len &&
8470 !strncmp(cc->name, cands->name, cands->name_len))
8471 return cc;
8472 return NULL;
8473}
8474
8475static size_t sizeof_cands(int cnt)
8476{
8477 return offsetof(struct bpf_cand_cache, cands[cnt]);
8478}
8479
8480static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
8481 struct bpf_cand_cache **cache,
8482 int cache_size)
8483{
8484 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
8485
8486 if (*cc) {
8487 bpf_free_cands_from_cache(*cc);
8488 *cc = NULL;
8489 }
8490 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
8491 if (!new_cands) {
8492 bpf_free_cands(cands);
8493 return ERR_PTR(-ENOMEM);
8494 }
8495 /* strdup the name, since it will stay in cache.
8496 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
8497 */
8498 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
8499 bpf_free_cands(cands);
8500 if (!new_cands->name) {
8501 kfree(new_cands);
8502 return ERR_PTR(-ENOMEM);
8503 }
8504 *cc = new_cands;
8505 return new_cands;
8506}
8507
8508#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8509static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
8510 int cache_size)
8511{
8512 struct bpf_cand_cache *cc;
8513 int i, j;
8514
8515 for (i = 0; i < cache_size; i++) {
8516 cc = cache[i];
8517 if (!cc)
8518 continue;
8519 if (!btf) {
8520 /* when new module is loaded purge all of module_cand_cache,
8521 * since new module might have candidates with the name
8522 * that matches cached cands.
8523 */
8524 bpf_free_cands_from_cache(cc);
8525 cache[i] = NULL;
8526 continue;
8527 }
8528 /* when module is unloaded purge cache entries
8529 * that match module's btf
8530 */
8531 for (j = 0; j < cc->cnt; j++)
8532 if (cc->cands[j].btf == btf) {
8533 bpf_free_cands_from_cache(cc);
8534 cache[i] = NULL;
8535 break;
8536 }
8537 }
8538
8539}
8540
8541static void purge_cand_cache(struct btf *btf)
8542{
8543 mutex_lock(&cand_cache_mutex);
8544 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8545 mutex_unlock(&cand_cache_mutex);
8546}
8547#endif
8548
8549static struct bpf_cand_cache *
8550bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
8551 int targ_start_id)
8552{
8553 struct bpf_cand_cache *new_cands;
8554 const struct btf_type *t;
8555 const char *targ_name;
8556 size_t targ_essent_len;
8557 int n, i;
8558
8559 n = btf_nr_types(targ_btf);
8560 for (i = targ_start_id; i < n; i++) {
8561 t = btf_type_by_id(targ_btf, i);
8562 if (btf_kind(t) != cands->kind)
8563 continue;
8564
8565 targ_name = btf_name_by_offset(targ_btf, t->name_off);
8566 if (!targ_name)
8567 continue;
8568
8569 /* the resched point is before strncmp to make sure that search
8570 * for non-existing name will have a chance to schedule().
8571 */
8572 cond_resched();
8573
8574 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
8575 continue;
8576
8577 targ_essent_len = bpf_core_essential_name_len(targ_name);
8578 if (targ_essent_len != cands->name_len)
8579 continue;
8580
8581 /* most of the time there is only one candidate for a given kind+name pair */
8582 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
8583 if (!new_cands) {
8584 bpf_free_cands(cands);
8585 return ERR_PTR(-ENOMEM);
8586 }
8587
8588 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
8589 bpf_free_cands(cands);
8590 cands = new_cands;
8591 cands->cands[cands->cnt].btf = targ_btf;
8592 cands->cands[cands->cnt].id = i;
8593 cands->cnt++;
8594 }
8595 return cands;
8596}
8597
8598static struct bpf_cand_cache *
8599bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
8600{
8601 struct bpf_cand_cache *cands, *cc, local_cand = {};
8602 const struct btf *local_btf = ctx->btf;
8603 const struct btf_type *local_type;
8604 const struct btf *main_btf;
8605 size_t local_essent_len;
8606 struct btf *mod_btf;
8607 const char *name;
8608 int id;
8609
8610 main_btf = bpf_get_btf_vmlinux();
8611 if (IS_ERR(main_btf))
8612 return ERR_CAST(main_btf);
8613 if (!main_btf)
8614 return ERR_PTR(-EINVAL);
8615
8616 local_type = btf_type_by_id(local_btf, local_type_id);
8617 if (!local_type)
8618 return ERR_PTR(-EINVAL);
8619
8620 name = btf_name_by_offset(local_btf, local_type->name_off);
8621 if (str_is_empty(name))
8622 return ERR_PTR(-EINVAL);
8623 local_essent_len = bpf_core_essential_name_len(name);
8624
8625 cands = &local_cand;
8626 cands->name = name;
8627 cands->kind = btf_kind(local_type);
8628 cands->name_len = local_essent_len;
8629
8630 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8631 /* cands is a pointer to stack here */
8632 if (cc) {
8633 if (cc->cnt)
8634 return cc;
8635 goto check_modules;
8636 }
8637
8638 /* Attempt to find target candidates in vmlinux BTF first */
8639 cands = bpf_core_add_cands(cands, main_btf, 1);
8640 if (IS_ERR(cands))
8641 return ERR_CAST(cands);
8642
8643 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
8644
8645 /* populate cache even when cands->cnt == 0 */
8646 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8647 if (IS_ERR(cc))
8648 return ERR_CAST(cc);
8649
8650 /* if vmlinux BTF has any candidate, don't go for module BTFs */
8651 if (cc->cnt)
8652 return cc;
8653
8654check_modules:
8655 /* cands is a pointer to stack here and cands->cnt == 0 */
8656 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8657 if (cc)
8658 /* if cache has it return it even if cc->cnt == 0 */
8659 return cc;
8660
8661 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
8662 spin_lock_bh(&btf_idr_lock);
8663 idr_for_each_entry(&btf_idr, mod_btf, id) {
8664 if (!btf_is_module(mod_btf))
8665 continue;
8666 /* linear search could be slow hence unlock/lock
8667 * the IDR to avoiding holding it for too long
8668 */
8669 btf_get(mod_btf);
8670 spin_unlock_bh(&btf_idr_lock);
8671 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
8672 btf_put(mod_btf);
8673 if (IS_ERR(cands))
8674 return ERR_CAST(cands);
8675 spin_lock_bh(&btf_idr_lock);
8676 }
8677 spin_unlock_bh(&btf_idr_lock);
8678 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
8679 * or pointer to stack if cands->cnd == 0.
8680 * Copy it into the cache even when cands->cnt == 0 and
8681 * return the result.
8682 */
8683 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8684}
8685
8686int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
8687 int relo_idx, void *insn)
8688{
8689 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
8690 struct bpf_core_cand_list cands = {};
8691 struct bpf_core_relo_res targ_res;
8692 struct bpf_core_spec *specs;
8693 int err;
8694
8695 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
8696 * into arrays of btf_ids of struct fields and array indices.
8697 */
8698 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
8699 if (!specs)
8700 return -ENOMEM;
8701
8702 if (need_cands) {
8703 struct bpf_cand_cache *cc;
8704 int i;
8705
8706 mutex_lock(&cand_cache_mutex);
8707 cc = bpf_core_find_cands(ctx, relo->type_id);
8708 if (IS_ERR(cc)) {
8709 bpf_log(ctx->log, "target candidate search failed for %d\n",
8710 relo->type_id);
8711 err = PTR_ERR(cc);
8712 goto out;
8713 }
8714 if (cc->cnt) {
8715 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
8716 if (!cands.cands) {
8717 err = -ENOMEM;
8718 goto out;
8719 }
8720 }
8721 for (i = 0; i < cc->cnt; i++) {
8722 bpf_log(ctx->log,
8723 "CO-RE relocating %s %s: found target candidate [%d]\n",
8724 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
8725 cands.cands[i].btf = cc->cands[i].btf;
8726 cands.cands[i].id = cc->cands[i].id;
8727 }
8728 cands.len = cc->cnt;
8729 /* cand_cache_mutex needs to span the cache lookup and
8730 * copy of btf pointer into bpf_core_cand_list,
8731 * since module can be unloaded while bpf_core_calc_relo_insn
8732 * is working with module's btf.
8733 */
8734 }
8735
8736 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
8737 &targ_res);
8738 if (err)
8739 goto out;
8740
8741 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
8742 &targ_res);
8743
8744out:
8745 kfree(specs);
8746 if (need_cands) {
8747 kfree(cands.cands);
8748 mutex_unlock(&cand_cache_mutex);
8749 if (ctx->log->level & BPF_LOG_LEVEL2)
8750 print_cand_cache(ctx->log);
8751 }
8752 return err;
8753}
8754
8755bool btf_nested_type_is_trusted(struct bpf_verifier_log *log,
8756 const struct bpf_reg_state *reg,
8757 const char *field_name, u32 btf_id, const char *suffix)
8758{
8759 struct btf *btf = reg->btf;
8760 const struct btf_type *walk_type, *safe_type;
8761 const char *tname;
8762 char safe_tname[64];
8763 long ret, safe_id;
8764 const struct btf_member *member;
8765 u32 i;
8766
8767 walk_type = btf_type_by_id(btf, reg->btf_id);
8768 if (!walk_type)
8769 return false;
8770
8771 tname = btf_name_by_offset(btf, walk_type->name_off);
8772
8773 ret = snprintf(safe_tname, sizeof(safe_tname), "%s%s", tname, suffix);
8774 if (ret >= sizeof(safe_tname))
8775 return false;
8776
8777 safe_id = btf_find_by_name_kind(btf, safe_tname, BTF_INFO_KIND(walk_type->info));
8778 if (safe_id < 0)
8779 return false;
8780
8781 safe_type = btf_type_by_id(btf, safe_id);
8782 if (!safe_type)
8783 return false;
8784
8785 for_each_member(i, safe_type, member) {
8786 const char *m_name = __btf_name_by_offset(btf, member->name_off);
8787 const struct btf_type *mtype = btf_type_by_id(btf, member->type);
8788 u32 id;
8789
8790 if (!btf_type_is_ptr(mtype))
8791 continue;
8792
8793 btf_type_skip_modifiers(btf, mtype->type, &id);
8794 /* If we match on both type and name, the field is considered trusted. */
8795 if (btf_id == id && !strcmp(field_name, m_name))
8796 return true;
8797 }
8798
8799 return false;
8800}
8801
8802bool btf_type_ids_nocast_alias(struct bpf_verifier_log *log,
8803 const struct btf *reg_btf, u32 reg_id,
8804 const struct btf *arg_btf, u32 arg_id)
8805{
8806 const char *reg_name, *arg_name, *search_needle;
8807 const struct btf_type *reg_type, *arg_type;
8808 int reg_len, arg_len, cmp_len;
8809 size_t pattern_len = sizeof(NOCAST_ALIAS_SUFFIX) - sizeof(char);
8810
8811 reg_type = btf_type_by_id(reg_btf, reg_id);
8812 if (!reg_type)
8813 return false;
8814
8815 arg_type = btf_type_by_id(arg_btf, arg_id);
8816 if (!arg_type)
8817 return false;
8818
8819 reg_name = btf_name_by_offset(reg_btf, reg_type->name_off);
8820 arg_name = btf_name_by_offset(arg_btf, arg_type->name_off);
8821
8822 reg_len = strlen(reg_name);
8823 arg_len = strlen(arg_name);
8824
8825 /* Exactly one of the two type names may be suffixed with ___init, so
8826 * if the strings are the same size, they can't possibly be no-cast
8827 * aliases of one another. If you have two of the same type names, e.g.
8828 * they're both nf_conn___init, it would be improper to return true
8829 * because they are _not_ no-cast aliases, they are the same type.
8830 */
8831 if (reg_len == arg_len)
8832 return false;
8833
8834 /* Either of the two names must be the other name, suffixed with ___init. */
8835 if ((reg_len != arg_len + pattern_len) &&
8836 (arg_len != reg_len + pattern_len))
8837 return false;
8838
8839 if (reg_len < arg_len) {
8840 search_needle = strstr(arg_name, NOCAST_ALIAS_SUFFIX);
8841 cmp_len = reg_len;
8842 } else {
8843 search_needle = strstr(reg_name, NOCAST_ALIAS_SUFFIX);
8844 cmp_len = arg_len;
8845 }
8846
8847 if (!search_needle)
8848 return false;
8849
8850 /* ___init suffix must come at the end of the name */
8851 if (*(search_needle + pattern_len) != '\0')
8852 return false;
8853
8854 return !strncmp(reg_name, arg_name, cmp_len);
8855}
8856
8857#ifdef CONFIG_BPF_JIT
8858static int
8859btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops,
8860 struct bpf_verifier_log *log)
8861{
8862 struct btf_struct_ops_tab *tab, *new_tab;
8863 int i, err;
8864
8865 tab = btf->struct_ops_tab;
8866 if (!tab) {
8867 tab = kzalloc(offsetof(struct btf_struct_ops_tab, ops[4]),
8868 GFP_KERNEL);
8869 if (!tab)
8870 return -ENOMEM;
8871 tab->capacity = 4;
8872 btf->struct_ops_tab = tab;
8873 }
8874
8875 for (i = 0; i < tab->cnt; i++)
8876 if (tab->ops[i].st_ops == st_ops)
8877 return -EEXIST;
8878
8879 if (tab->cnt == tab->capacity) {
8880 new_tab = krealloc(tab,
8881 offsetof(struct btf_struct_ops_tab,
8882 ops[tab->capacity * 2]),
8883 GFP_KERNEL);
8884 if (!new_tab)
8885 return -ENOMEM;
8886 tab = new_tab;
8887 tab->capacity *= 2;
8888 btf->struct_ops_tab = tab;
8889 }
8890
8891 tab->ops[btf->struct_ops_tab->cnt].st_ops = st_ops;
8892
8893 err = bpf_struct_ops_desc_init(&tab->ops[btf->struct_ops_tab->cnt], btf, log);
8894 if (err)
8895 return err;
8896
8897 btf->struct_ops_tab->cnt++;
8898
8899 return 0;
8900}
8901
8902const struct bpf_struct_ops_desc *
8903bpf_struct_ops_find_value(struct btf *btf, u32 value_id)
8904{
8905 const struct bpf_struct_ops_desc *st_ops_list;
8906 unsigned int i;
8907 u32 cnt;
8908
8909 if (!value_id)
8910 return NULL;
8911 if (!btf->struct_ops_tab)
8912 return NULL;
8913
8914 cnt = btf->struct_ops_tab->cnt;
8915 st_ops_list = btf->struct_ops_tab->ops;
8916 for (i = 0; i < cnt; i++) {
8917 if (st_ops_list[i].value_id == value_id)
8918 return &st_ops_list[i];
8919 }
8920
8921 return NULL;
8922}
8923
8924const struct bpf_struct_ops_desc *
8925bpf_struct_ops_find(struct btf *btf, u32 type_id)
8926{
8927 const struct bpf_struct_ops_desc *st_ops_list;
8928 unsigned int i;
8929 u32 cnt;
8930
8931 if (!type_id)
8932 return NULL;
8933 if (!btf->struct_ops_tab)
8934 return NULL;
8935
8936 cnt = btf->struct_ops_tab->cnt;
8937 st_ops_list = btf->struct_ops_tab->ops;
8938 for (i = 0; i < cnt; i++) {
8939 if (st_ops_list[i].type_id == type_id)
8940 return &st_ops_list[i];
8941 }
8942
8943 return NULL;
8944}
8945
8946int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops)
8947{
8948 struct bpf_verifier_log *log;
8949 struct btf *btf;
8950 int err = 0;
8951
8952 btf = btf_get_module_btf(st_ops->owner);
8953 if (!btf)
8954 return check_btf_kconfigs(st_ops->owner, "struct_ops");
8955 if (IS_ERR(btf))
8956 return PTR_ERR(btf);
8957
8958 log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN);
8959 if (!log) {
8960 err = -ENOMEM;
8961 goto errout;
8962 }
8963
8964 log->level = BPF_LOG_KERNEL;
8965
8966 err = btf_add_struct_ops(btf, st_ops, log);
8967
8968errout:
8969 kfree(log);
8970 btf_put(btf);
8971
8972 return err;
8973}
8974EXPORT_SYMBOL_GPL(__register_bpf_struct_ops);
8975#endif
8976
8977bool btf_param_match_suffix(const struct btf *btf,
8978 const struct btf_param *arg,
8979 const char *suffix)
8980{
8981 int suffix_len = strlen(suffix), len;
8982 const char *param_name;
8983
8984 /* In the future, this can be ported to use BTF tagging */
8985 param_name = btf_name_by_offset(btf, arg->name_off);
8986 if (str_is_empty(param_name))
8987 return false;
8988 len = strlen(param_name);
8989 if (len <= suffix_len)
8990 return false;
8991 param_name += len - suffix_len;
8992 return !strncmp(param_name, suffix, suffix_len);
8993}