Loading...
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#include <net/sock.h>
29#include "../tools/lib/bpf/relo_core.h"
30
31/* BTF (BPF Type Format) is the meta data format which describes
32 * the data types of BPF program/map. Hence, it basically focus
33 * on the C programming language which the modern BPF is primary
34 * using.
35 *
36 * ELF Section:
37 * ~~~~~~~~~~~
38 * The BTF data is stored under the ".BTF" ELF section
39 *
40 * struct btf_type:
41 * ~~~~~~~~~~~~~~~
42 * Each 'struct btf_type' object describes a C data type.
43 * Depending on the type it is describing, a 'struct btf_type'
44 * object may be followed by more data. F.e.
45 * To describe an array, 'struct btf_type' is followed by
46 * 'struct btf_array'.
47 *
48 * 'struct btf_type' and any extra data following it are
49 * 4 bytes aligned.
50 *
51 * Type section:
52 * ~~~~~~~~~~~~~
53 * The BTF type section contains a list of 'struct btf_type' objects.
54 * Each one describes a C type. Recall from the above section
55 * that a 'struct btf_type' object could be immediately followed by extra
56 * data in order to describe some particular C types.
57 *
58 * type_id:
59 * ~~~~~~~
60 * Each btf_type object is identified by a type_id. The type_id
61 * is implicitly implied by the location of the btf_type object in
62 * the BTF type section. The first one has type_id 1. The second
63 * one has type_id 2...etc. Hence, an earlier btf_type has
64 * a smaller type_id.
65 *
66 * A btf_type object may refer to another btf_type object by using
67 * type_id (i.e. the "type" in the "struct btf_type").
68 *
69 * NOTE that we cannot assume any reference-order.
70 * A btf_type object can refer to an earlier btf_type object
71 * but it can also refer to a later btf_type object.
72 *
73 * For example, to describe "const void *". A btf_type
74 * object describing "const" may refer to another btf_type
75 * object describing "void *". This type-reference is done
76 * by specifying type_id:
77 *
78 * [1] CONST (anon) type_id=2
79 * [2] PTR (anon) type_id=0
80 *
81 * The above is the btf_verifier debug log:
82 * - Each line started with "[?]" is a btf_type object
83 * - [?] is the type_id of the btf_type object.
84 * - CONST/PTR is the BTF_KIND_XXX
85 * - "(anon)" is the name of the type. It just
86 * happens that CONST and PTR has no name.
87 * - type_id=XXX is the 'u32 type' in btf_type
88 *
89 * NOTE: "void" has type_id 0
90 *
91 * String section:
92 * ~~~~~~~~~~~~~~
93 * The BTF string section contains the names used by the type section.
94 * Each string is referred by an "offset" from the beginning of the
95 * string section.
96 *
97 * Each string is '\0' terminated.
98 *
99 * The first character in the string section must be '\0'
100 * which is used to mean 'anonymous'. Some btf_type may not
101 * have a name.
102 */
103
104/* BTF verification:
105 *
106 * To verify BTF data, two passes are needed.
107 *
108 * Pass #1
109 * ~~~~~~~
110 * The first pass is to collect all btf_type objects to
111 * an array: "btf->types".
112 *
113 * Depending on the C type that a btf_type is describing,
114 * a btf_type may be followed by extra data. We don't know
115 * how many btf_type is there, and more importantly we don't
116 * know where each btf_type is located in the type section.
117 *
118 * Without knowing the location of each type_id, most verifications
119 * cannot be done. e.g. an earlier btf_type may refer to a later
120 * btf_type (recall the "const void *" above), so we cannot
121 * check this type-reference in the first pass.
122 *
123 * In the first pass, it still does some verifications (e.g.
124 * checking the name is a valid offset to the string section).
125 *
126 * Pass #2
127 * ~~~~~~~
128 * The main focus is to resolve a btf_type that is referring
129 * to another type.
130 *
131 * We have to ensure the referring type:
132 * 1) does exist in the BTF (i.e. in btf->types[])
133 * 2) does not cause a loop:
134 * struct A {
135 * struct B b;
136 * };
137 *
138 * struct B {
139 * struct A a;
140 * };
141 *
142 * btf_type_needs_resolve() decides if a btf_type needs
143 * to be resolved.
144 *
145 * The needs_resolve type implements the "resolve()" ops which
146 * essentially does a DFS and detects backedge.
147 *
148 * During resolve (or DFS), different C types have different
149 * "RESOLVED" conditions.
150 *
151 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
152 * members because a member is always referring to another
153 * type. A struct's member can be treated as "RESOLVED" if
154 * it is referring to a BTF_KIND_PTR. Otherwise, the
155 * following valid C struct would be rejected:
156 *
157 * struct A {
158 * int m;
159 * struct A *a;
160 * };
161 *
162 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
163 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
164 * detect a pointer loop, e.g.:
165 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
166 * ^ |
167 * +-----------------------------------------+
168 *
169 */
170
171#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
172#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
173#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
174#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
175#define BITS_ROUNDUP_BYTES(bits) \
176 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
177
178#define BTF_INFO_MASK 0x9f00ffff
179#define BTF_INT_MASK 0x0fffffff
180#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
181#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
182
183/* 16MB for 64k structs and each has 16 members and
184 * a few MB spaces for the string section.
185 * The hard limit is S32_MAX.
186 */
187#define BTF_MAX_SIZE (16 * 1024 * 1024)
188
189#define for_each_member_from(i, from, struct_type, member) \
190 for (i = from, member = btf_type_member(struct_type) + from; \
191 i < btf_type_vlen(struct_type); \
192 i++, member++)
193
194#define for_each_vsi_from(i, from, struct_type, member) \
195 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
196 i < btf_type_vlen(struct_type); \
197 i++, member++)
198
199DEFINE_IDR(btf_idr);
200DEFINE_SPINLOCK(btf_idr_lock);
201
202enum btf_kfunc_hook {
203 BTF_KFUNC_HOOK_COMMON,
204 BTF_KFUNC_HOOK_XDP,
205 BTF_KFUNC_HOOK_TC,
206 BTF_KFUNC_HOOK_STRUCT_OPS,
207 BTF_KFUNC_HOOK_TRACING,
208 BTF_KFUNC_HOOK_SYSCALL,
209 BTF_KFUNC_HOOK_FMODRET,
210 BTF_KFUNC_HOOK_MAX,
211};
212
213enum {
214 BTF_KFUNC_SET_MAX_CNT = 256,
215 BTF_DTOR_KFUNC_MAX_CNT = 256,
216};
217
218struct btf_kfunc_set_tab {
219 struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
220};
221
222struct btf_id_dtor_kfunc_tab {
223 u32 cnt;
224 struct btf_id_dtor_kfunc dtors[];
225};
226
227struct btf {
228 void *data;
229 struct btf_type **types;
230 u32 *resolved_ids;
231 u32 *resolved_sizes;
232 const char *strings;
233 void *nohdr_data;
234 struct btf_header hdr;
235 u32 nr_types; /* includes VOID for base BTF */
236 u32 types_size;
237 u32 data_size;
238 refcount_t refcnt;
239 u32 id;
240 struct rcu_head rcu;
241 struct btf_kfunc_set_tab *kfunc_set_tab;
242 struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
243 struct btf_struct_metas *struct_meta_tab;
244
245 /* split BTF support */
246 struct btf *base_btf;
247 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
248 u32 start_str_off; /* first string offset (0 for base BTF) */
249 char name[MODULE_NAME_LEN];
250 bool kernel_btf;
251};
252
253enum verifier_phase {
254 CHECK_META,
255 CHECK_TYPE,
256};
257
258struct resolve_vertex {
259 const struct btf_type *t;
260 u32 type_id;
261 u16 next_member;
262};
263
264enum visit_state {
265 NOT_VISITED,
266 VISITED,
267 RESOLVED,
268};
269
270enum resolve_mode {
271 RESOLVE_TBD, /* To Be Determined */
272 RESOLVE_PTR, /* Resolving for Pointer */
273 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
274 * or array
275 */
276};
277
278#define MAX_RESOLVE_DEPTH 32
279
280struct btf_sec_info {
281 u32 off;
282 u32 len;
283};
284
285struct btf_verifier_env {
286 struct btf *btf;
287 u8 *visit_states;
288 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
289 struct bpf_verifier_log log;
290 u32 log_type_id;
291 u32 top_stack;
292 enum verifier_phase phase;
293 enum resolve_mode resolve_mode;
294};
295
296static const char * const btf_kind_str[NR_BTF_KINDS] = {
297 [BTF_KIND_UNKN] = "UNKNOWN",
298 [BTF_KIND_INT] = "INT",
299 [BTF_KIND_PTR] = "PTR",
300 [BTF_KIND_ARRAY] = "ARRAY",
301 [BTF_KIND_STRUCT] = "STRUCT",
302 [BTF_KIND_UNION] = "UNION",
303 [BTF_KIND_ENUM] = "ENUM",
304 [BTF_KIND_FWD] = "FWD",
305 [BTF_KIND_TYPEDEF] = "TYPEDEF",
306 [BTF_KIND_VOLATILE] = "VOLATILE",
307 [BTF_KIND_CONST] = "CONST",
308 [BTF_KIND_RESTRICT] = "RESTRICT",
309 [BTF_KIND_FUNC] = "FUNC",
310 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
311 [BTF_KIND_VAR] = "VAR",
312 [BTF_KIND_DATASEC] = "DATASEC",
313 [BTF_KIND_FLOAT] = "FLOAT",
314 [BTF_KIND_DECL_TAG] = "DECL_TAG",
315 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
316 [BTF_KIND_ENUM64] = "ENUM64",
317};
318
319const char *btf_type_str(const struct btf_type *t)
320{
321 return btf_kind_str[BTF_INFO_KIND(t->info)];
322}
323
324/* Chunk size we use in safe copy of data to be shown. */
325#define BTF_SHOW_OBJ_SAFE_SIZE 32
326
327/*
328 * This is the maximum size of a base type value (equivalent to a
329 * 128-bit int); if we are at the end of our safe buffer and have
330 * less than 16 bytes space we can't be assured of being able
331 * to copy the next type safely, so in such cases we will initiate
332 * a new copy.
333 */
334#define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
335
336/* Type name size */
337#define BTF_SHOW_NAME_SIZE 80
338
339/*
340 * Common data to all BTF show operations. Private show functions can add
341 * their own data to a structure containing a struct btf_show and consult it
342 * in the show callback. See btf_type_show() below.
343 *
344 * One challenge with showing nested data is we want to skip 0-valued
345 * data, but in order to figure out whether a nested object is all zeros
346 * we need to walk through it. As a result, we need to make two passes
347 * when handling structs, unions and arrays; the first path simply looks
348 * for nonzero data, while the second actually does the display. The first
349 * pass is signalled by show->state.depth_check being set, and if we
350 * encounter a non-zero value we set show->state.depth_to_show to
351 * the depth at which we encountered it. When we have completed the
352 * first pass, we will know if anything needs to be displayed if
353 * depth_to_show > depth. See btf_[struct,array]_show() for the
354 * implementation of this.
355 *
356 * Another problem is we want to ensure the data for display is safe to
357 * access. To support this, the anonymous "struct {} obj" tracks the data
358 * object and our safe copy of it. We copy portions of the data needed
359 * to the object "copy" buffer, but because its size is limited to
360 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
361 * traverse larger objects for display.
362 *
363 * The various data type show functions all start with a call to
364 * btf_show_start_type() which returns a pointer to the safe copy
365 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
366 * raw data itself). btf_show_obj_safe() is responsible for
367 * using copy_from_kernel_nofault() to update the safe data if necessary
368 * as we traverse the object's data. skbuff-like semantics are
369 * used:
370 *
371 * - obj.head points to the start of the toplevel object for display
372 * - obj.size is the size of the toplevel object
373 * - obj.data points to the current point in the original data at
374 * which our safe data starts. obj.data will advance as we copy
375 * portions of the data.
376 *
377 * In most cases a single copy will suffice, but larger data structures
378 * such as "struct task_struct" will require many copies. The logic in
379 * btf_show_obj_safe() handles the logic that determines if a new
380 * copy_from_kernel_nofault() is needed.
381 */
382struct btf_show {
383 u64 flags;
384 void *target; /* target of show operation (seq file, buffer) */
385 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
386 const struct btf *btf;
387 /* below are used during iteration */
388 struct {
389 u8 depth;
390 u8 depth_to_show;
391 u8 depth_check;
392 u8 array_member:1,
393 array_terminated:1;
394 u16 array_encoding;
395 u32 type_id;
396 int status; /* non-zero for error */
397 const struct btf_type *type;
398 const struct btf_member *member;
399 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
400 } state;
401 struct {
402 u32 size;
403 void *head;
404 void *data;
405 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
406 } obj;
407};
408
409struct btf_kind_operations {
410 s32 (*check_meta)(struct btf_verifier_env *env,
411 const struct btf_type *t,
412 u32 meta_left);
413 int (*resolve)(struct btf_verifier_env *env,
414 const struct resolve_vertex *v);
415 int (*check_member)(struct btf_verifier_env *env,
416 const struct btf_type *struct_type,
417 const struct btf_member *member,
418 const struct btf_type *member_type);
419 int (*check_kflag_member)(struct btf_verifier_env *env,
420 const struct btf_type *struct_type,
421 const struct btf_member *member,
422 const struct btf_type *member_type);
423 void (*log_details)(struct btf_verifier_env *env,
424 const struct btf_type *t);
425 void (*show)(const struct btf *btf, const struct btf_type *t,
426 u32 type_id, void *data, u8 bits_offsets,
427 struct btf_show *show);
428};
429
430static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
431static struct btf_type btf_void;
432
433static int btf_resolve(struct btf_verifier_env *env,
434 const struct btf_type *t, u32 type_id);
435
436static int btf_func_check(struct btf_verifier_env *env,
437 const struct btf_type *t);
438
439static bool btf_type_is_modifier(const struct btf_type *t)
440{
441 /* Some of them is not strictly a C modifier
442 * but they are grouped into the same bucket
443 * for BTF concern:
444 * A type (t) that refers to another
445 * type through t->type AND its size cannot
446 * be determined without following the t->type.
447 *
448 * ptr does not fall into this bucket
449 * because its size is always sizeof(void *).
450 */
451 switch (BTF_INFO_KIND(t->info)) {
452 case BTF_KIND_TYPEDEF:
453 case BTF_KIND_VOLATILE:
454 case BTF_KIND_CONST:
455 case BTF_KIND_RESTRICT:
456 case BTF_KIND_TYPE_TAG:
457 return true;
458 }
459
460 return false;
461}
462
463bool btf_type_is_void(const struct btf_type *t)
464{
465 return t == &btf_void;
466}
467
468static bool btf_type_is_fwd(const struct btf_type *t)
469{
470 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
471}
472
473static bool btf_type_nosize(const struct btf_type *t)
474{
475 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
476 btf_type_is_func(t) || btf_type_is_func_proto(t);
477}
478
479static bool btf_type_nosize_or_null(const struct btf_type *t)
480{
481 return !t || btf_type_nosize(t);
482}
483
484static bool btf_type_is_datasec(const struct btf_type *t)
485{
486 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
487}
488
489static bool btf_type_is_decl_tag(const struct btf_type *t)
490{
491 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
492}
493
494static bool btf_type_is_decl_tag_target(const struct btf_type *t)
495{
496 return btf_type_is_func(t) || btf_type_is_struct(t) ||
497 btf_type_is_var(t) || btf_type_is_typedef(t);
498}
499
500u32 btf_nr_types(const struct btf *btf)
501{
502 u32 total = 0;
503
504 while (btf) {
505 total += btf->nr_types;
506 btf = btf->base_btf;
507 }
508
509 return total;
510}
511
512s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
513{
514 const struct btf_type *t;
515 const char *tname;
516 u32 i, total;
517
518 total = btf_nr_types(btf);
519 for (i = 1; i < total; i++) {
520 t = btf_type_by_id(btf, i);
521 if (BTF_INFO_KIND(t->info) != kind)
522 continue;
523
524 tname = btf_name_by_offset(btf, t->name_off);
525 if (!strcmp(tname, name))
526 return i;
527 }
528
529 return -ENOENT;
530}
531
532static s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
533{
534 struct btf *btf;
535 s32 ret;
536 int id;
537
538 btf = bpf_get_btf_vmlinux();
539 if (IS_ERR(btf))
540 return PTR_ERR(btf);
541 if (!btf)
542 return -EINVAL;
543
544 ret = btf_find_by_name_kind(btf, name, kind);
545 /* ret is never zero, since btf_find_by_name_kind returns
546 * positive btf_id or negative error.
547 */
548 if (ret > 0) {
549 btf_get(btf);
550 *btf_p = btf;
551 return ret;
552 }
553
554 /* If name is not found in vmlinux's BTF then search in module's BTFs */
555 spin_lock_bh(&btf_idr_lock);
556 idr_for_each_entry(&btf_idr, btf, id) {
557 if (!btf_is_module(btf))
558 continue;
559 /* linear search could be slow hence unlock/lock
560 * the IDR to avoiding holding it for too long
561 */
562 btf_get(btf);
563 spin_unlock_bh(&btf_idr_lock);
564 ret = btf_find_by_name_kind(btf, name, kind);
565 if (ret > 0) {
566 *btf_p = btf;
567 return ret;
568 }
569 spin_lock_bh(&btf_idr_lock);
570 btf_put(btf);
571 }
572 spin_unlock_bh(&btf_idr_lock);
573 return ret;
574}
575
576const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
577 u32 id, u32 *res_id)
578{
579 const struct btf_type *t = btf_type_by_id(btf, id);
580
581 while (btf_type_is_modifier(t)) {
582 id = t->type;
583 t = btf_type_by_id(btf, t->type);
584 }
585
586 if (res_id)
587 *res_id = id;
588
589 return t;
590}
591
592const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
593 u32 id, u32 *res_id)
594{
595 const struct btf_type *t;
596
597 t = btf_type_skip_modifiers(btf, id, NULL);
598 if (!btf_type_is_ptr(t))
599 return NULL;
600
601 return btf_type_skip_modifiers(btf, t->type, res_id);
602}
603
604const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
605 u32 id, u32 *res_id)
606{
607 const struct btf_type *ptype;
608
609 ptype = btf_type_resolve_ptr(btf, id, res_id);
610 if (ptype && btf_type_is_func_proto(ptype))
611 return ptype;
612
613 return NULL;
614}
615
616/* Types that act only as a source, not sink or intermediate
617 * type when resolving.
618 */
619static bool btf_type_is_resolve_source_only(const struct btf_type *t)
620{
621 return btf_type_is_var(t) ||
622 btf_type_is_decl_tag(t) ||
623 btf_type_is_datasec(t);
624}
625
626/* What types need to be resolved?
627 *
628 * btf_type_is_modifier() is an obvious one.
629 *
630 * btf_type_is_struct() because its member refers to
631 * another type (through member->type).
632 *
633 * btf_type_is_var() because the variable refers to
634 * another type. btf_type_is_datasec() holds multiple
635 * btf_type_is_var() types that need resolving.
636 *
637 * btf_type_is_array() because its element (array->type)
638 * refers to another type. Array can be thought of a
639 * special case of struct while array just has the same
640 * member-type repeated by array->nelems of times.
641 */
642static bool btf_type_needs_resolve(const struct btf_type *t)
643{
644 return btf_type_is_modifier(t) ||
645 btf_type_is_ptr(t) ||
646 btf_type_is_struct(t) ||
647 btf_type_is_array(t) ||
648 btf_type_is_var(t) ||
649 btf_type_is_func(t) ||
650 btf_type_is_decl_tag(t) ||
651 btf_type_is_datasec(t);
652}
653
654/* t->size can be used */
655static bool btf_type_has_size(const struct btf_type *t)
656{
657 switch (BTF_INFO_KIND(t->info)) {
658 case BTF_KIND_INT:
659 case BTF_KIND_STRUCT:
660 case BTF_KIND_UNION:
661 case BTF_KIND_ENUM:
662 case BTF_KIND_DATASEC:
663 case BTF_KIND_FLOAT:
664 case BTF_KIND_ENUM64:
665 return true;
666 }
667
668 return false;
669}
670
671static const char *btf_int_encoding_str(u8 encoding)
672{
673 if (encoding == 0)
674 return "(none)";
675 else if (encoding == BTF_INT_SIGNED)
676 return "SIGNED";
677 else if (encoding == BTF_INT_CHAR)
678 return "CHAR";
679 else if (encoding == BTF_INT_BOOL)
680 return "BOOL";
681 else
682 return "UNKN";
683}
684
685static u32 btf_type_int(const struct btf_type *t)
686{
687 return *(u32 *)(t + 1);
688}
689
690static const struct btf_array *btf_type_array(const struct btf_type *t)
691{
692 return (const struct btf_array *)(t + 1);
693}
694
695static const struct btf_enum *btf_type_enum(const struct btf_type *t)
696{
697 return (const struct btf_enum *)(t + 1);
698}
699
700static const struct btf_var *btf_type_var(const struct btf_type *t)
701{
702 return (const struct btf_var *)(t + 1);
703}
704
705static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
706{
707 return (const struct btf_decl_tag *)(t + 1);
708}
709
710static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
711{
712 return (const struct btf_enum64 *)(t + 1);
713}
714
715static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
716{
717 return kind_ops[BTF_INFO_KIND(t->info)];
718}
719
720static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
721{
722 if (!BTF_STR_OFFSET_VALID(offset))
723 return false;
724
725 while (offset < btf->start_str_off)
726 btf = btf->base_btf;
727
728 offset -= btf->start_str_off;
729 return offset < btf->hdr.str_len;
730}
731
732static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
733{
734 if ((first ? !isalpha(c) :
735 !isalnum(c)) &&
736 c != '_' &&
737 ((c == '.' && !dot_ok) ||
738 c != '.'))
739 return false;
740 return true;
741}
742
743static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
744{
745 while (offset < btf->start_str_off)
746 btf = btf->base_btf;
747
748 offset -= btf->start_str_off;
749 if (offset < btf->hdr.str_len)
750 return &btf->strings[offset];
751
752 return NULL;
753}
754
755static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
756{
757 /* offset must be valid */
758 const char *src = btf_str_by_offset(btf, offset);
759 const char *src_limit;
760
761 if (!__btf_name_char_ok(*src, true, dot_ok))
762 return false;
763
764 /* set a limit on identifier length */
765 src_limit = src + KSYM_NAME_LEN;
766 src++;
767 while (*src && src < src_limit) {
768 if (!__btf_name_char_ok(*src, false, dot_ok))
769 return false;
770 src++;
771 }
772
773 return !*src;
774}
775
776/* Only C-style identifier is permitted. This can be relaxed if
777 * necessary.
778 */
779static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
780{
781 return __btf_name_valid(btf, offset, false);
782}
783
784static bool btf_name_valid_section(const struct btf *btf, u32 offset)
785{
786 return __btf_name_valid(btf, offset, true);
787}
788
789static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
790{
791 const char *name;
792
793 if (!offset)
794 return "(anon)";
795
796 name = btf_str_by_offset(btf, offset);
797 return name ?: "(invalid-name-offset)";
798}
799
800const char *btf_name_by_offset(const struct btf *btf, u32 offset)
801{
802 return btf_str_by_offset(btf, offset);
803}
804
805const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
806{
807 while (type_id < btf->start_id)
808 btf = btf->base_btf;
809
810 type_id -= btf->start_id;
811 if (type_id >= btf->nr_types)
812 return NULL;
813 return btf->types[type_id];
814}
815EXPORT_SYMBOL_GPL(btf_type_by_id);
816
817/*
818 * Regular int is not a bit field and it must be either
819 * u8/u16/u32/u64 or __int128.
820 */
821static bool btf_type_int_is_regular(const struct btf_type *t)
822{
823 u8 nr_bits, nr_bytes;
824 u32 int_data;
825
826 int_data = btf_type_int(t);
827 nr_bits = BTF_INT_BITS(int_data);
828 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
829 if (BITS_PER_BYTE_MASKED(nr_bits) ||
830 BTF_INT_OFFSET(int_data) ||
831 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
832 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
833 nr_bytes != (2 * sizeof(u64)))) {
834 return false;
835 }
836
837 return true;
838}
839
840/*
841 * Check that given struct member is a regular int with expected
842 * offset and size.
843 */
844bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
845 const struct btf_member *m,
846 u32 expected_offset, u32 expected_size)
847{
848 const struct btf_type *t;
849 u32 id, int_data;
850 u8 nr_bits;
851
852 id = m->type;
853 t = btf_type_id_size(btf, &id, NULL);
854 if (!t || !btf_type_is_int(t))
855 return false;
856
857 int_data = btf_type_int(t);
858 nr_bits = BTF_INT_BITS(int_data);
859 if (btf_type_kflag(s)) {
860 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
861 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
862
863 /* if kflag set, int should be a regular int and
864 * bit offset should be at byte boundary.
865 */
866 return !bitfield_size &&
867 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
868 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
869 }
870
871 if (BTF_INT_OFFSET(int_data) ||
872 BITS_PER_BYTE_MASKED(m->offset) ||
873 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
874 BITS_PER_BYTE_MASKED(nr_bits) ||
875 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
876 return false;
877
878 return true;
879}
880
881/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
882static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
883 u32 id)
884{
885 const struct btf_type *t = btf_type_by_id(btf, id);
886
887 while (btf_type_is_modifier(t) &&
888 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
889 t = btf_type_by_id(btf, t->type);
890 }
891
892 return t;
893}
894
895#define BTF_SHOW_MAX_ITER 10
896
897#define BTF_KIND_BIT(kind) (1ULL << kind)
898
899/*
900 * Populate show->state.name with type name information.
901 * Format of type name is
902 *
903 * [.member_name = ] (type_name)
904 */
905static const char *btf_show_name(struct btf_show *show)
906{
907 /* BTF_MAX_ITER array suffixes "[]" */
908 const char *array_suffixes = "[][][][][][][][][][]";
909 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
910 /* BTF_MAX_ITER pointer suffixes "*" */
911 const char *ptr_suffixes = "**********";
912 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
913 const char *name = NULL, *prefix = "", *parens = "";
914 const struct btf_member *m = show->state.member;
915 const struct btf_type *t;
916 const struct btf_array *array;
917 u32 id = show->state.type_id;
918 const char *member = NULL;
919 bool show_member = false;
920 u64 kinds = 0;
921 int i;
922
923 show->state.name[0] = '\0';
924
925 /*
926 * Don't show type name if we're showing an array member;
927 * in that case we show the array type so don't need to repeat
928 * ourselves for each member.
929 */
930 if (show->state.array_member)
931 return "";
932
933 /* Retrieve member name, if any. */
934 if (m) {
935 member = btf_name_by_offset(show->btf, m->name_off);
936 show_member = strlen(member) > 0;
937 id = m->type;
938 }
939
940 /*
941 * Start with type_id, as we have resolved the struct btf_type *
942 * via btf_modifier_show() past the parent typedef to the child
943 * struct, int etc it is defined as. In such cases, the type_id
944 * still represents the starting type while the struct btf_type *
945 * in our show->state points at the resolved type of the typedef.
946 */
947 t = btf_type_by_id(show->btf, id);
948 if (!t)
949 return "";
950
951 /*
952 * The goal here is to build up the right number of pointer and
953 * array suffixes while ensuring the type name for a typedef
954 * is represented. Along the way we accumulate a list of
955 * BTF kinds we have encountered, since these will inform later
956 * display; for example, pointer types will not require an
957 * opening "{" for struct, we will just display the pointer value.
958 *
959 * We also want to accumulate the right number of pointer or array
960 * indices in the format string while iterating until we get to
961 * the typedef/pointee/array member target type.
962 *
963 * We start by pointing at the end of pointer and array suffix
964 * strings; as we accumulate pointers and arrays we move the pointer
965 * or array string backwards so it will show the expected number of
966 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
967 * and/or arrays and typedefs are supported as a precaution.
968 *
969 * We also want to get typedef name while proceeding to resolve
970 * type it points to so that we can add parentheses if it is a
971 * "typedef struct" etc.
972 */
973 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
974
975 switch (BTF_INFO_KIND(t->info)) {
976 case BTF_KIND_TYPEDEF:
977 if (!name)
978 name = btf_name_by_offset(show->btf,
979 t->name_off);
980 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
981 id = t->type;
982 break;
983 case BTF_KIND_ARRAY:
984 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
985 parens = "[";
986 if (!t)
987 return "";
988 array = btf_type_array(t);
989 if (array_suffix > array_suffixes)
990 array_suffix -= 2;
991 id = array->type;
992 break;
993 case BTF_KIND_PTR:
994 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
995 if (ptr_suffix > ptr_suffixes)
996 ptr_suffix -= 1;
997 id = t->type;
998 break;
999 default:
1000 id = 0;
1001 break;
1002 }
1003 if (!id)
1004 break;
1005 t = btf_type_skip_qualifiers(show->btf, id);
1006 }
1007 /* We may not be able to represent this type; bail to be safe */
1008 if (i == BTF_SHOW_MAX_ITER)
1009 return "";
1010
1011 if (!name)
1012 name = btf_name_by_offset(show->btf, t->name_off);
1013
1014 switch (BTF_INFO_KIND(t->info)) {
1015 case BTF_KIND_STRUCT:
1016 case BTF_KIND_UNION:
1017 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1018 "struct" : "union";
1019 /* if it's an array of struct/union, parens is already set */
1020 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1021 parens = "{";
1022 break;
1023 case BTF_KIND_ENUM:
1024 case BTF_KIND_ENUM64:
1025 prefix = "enum";
1026 break;
1027 default:
1028 break;
1029 }
1030
1031 /* pointer does not require parens */
1032 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1033 parens = "";
1034 /* typedef does not require struct/union/enum prefix */
1035 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1036 prefix = "";
1037
1038 if (!name)
1039 name = "";
1040
1041 /* Even if we don't want type name info, we want parentheses etc */
1042 if (show->flags & BTF_SHOW_NONAME)
1043 snprintf(show->state.name, sizeof(show->state.name), "%s",
1044 parens);
1045 else
1046 snprintf(show->state.name, sizeof(show->state.name),
1047 "%s%s%s(%s%s%s%s%s%s)%s",
1048 /* first 3 strings comprise ".member = " */
1049 show_member ? "." : "",
1050 show_member ? member : "",
1051 show_member ? " = " : "",
1052 /* ...next is our prefix (struct, enum, etc) */
1053 prefix,
1054 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1055 /* ...this is the type name itself */
1056 name,
1057 /* ...suffixed by the appropriate '*', '[]' suffixes */
1058 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1059 array_suffix, parens);
1060
1061 return show->state.name;
1062}
1063
1064static const char *__btf_show_indent(struct btf_show *show)
1065{
1066 const char *indents = " ";
1067 const char *indent = &indents[strlen(indents)];
1068
1069 if ((indent - show->state.depth) >= indents)
1070 return indent - show->state.depth;
1071 return indents;
1072}
1073
1074static const char *btf_show_indent(struct btf_show *show)
1075{
1076 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1077}
1078
1079static const char *btf_show_newline(struct btf_show *show)
1080{
1081 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1082}
1083
1084static const char *btf_show_delim(struct btf_show *show)
1085{
1086 if (show->state.depth == 0)
1087 return "";
1088
1089 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1090 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1091 return "|";
1092
1093 return ",";
1094}
1095
1096__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1097{
1098 va_list args;
1099
1100 if (!show->state.depth_check) {
1101 va_start(args, fmt);
1102 show->showfn(show, fmt, args);
1103 va_end(args);
1104 }
1105}
1106
1107/* Macros are used here as btf_show_type_value[s]() prepends and appends
1108 * format specifiers to the format specifier passed in; these do the work of
1109 * adding indentation, delimiters etc while the caller simply has to specify
1110 * the type value(s) in the format specifier + value(s).
1111 */
1112#define btf_show_type_value(show, fmt, value) \
1113 do { \
1114 if ((value) != (__typeof__(value))0 || \
1115 (show->flags & BTF_SHOW_ZERO) || \
1116 show->state.depth == 0) { \
1117 btf_show(show, "%s%s" fmt "%s%s", \
1118 btf_show_indent(show), \
1119 btf_show_name(show), \
1120 value, btf_show_delim(show), \
1121 btf_show_newline(show)); \
1122 if (show->state.depth > show->state.depth_to_show) \
1123 show->state.depth_to_show = show->state.depth; \
1124 } \
1125 } while (0)
1126
1127#define btf_show_type_values(show, fmt, ...) \
1128 do { \
1129 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1130 btf_show_name(show), \
1131 __VA_ARGS__, btf_show_delim(show), \
1132 btf_show_newline(show)); \
1133 if (show->state.depth > show->state.depth_to_show) \
1134 show->state.depth_to_show = show->state.depth; \
1135 } while (0)
1136
1137/* How much is left to copy to safe buffer after @data? */
1138static int btf_show_obj_size_left(struct btf_show *show, void *data)
1139{
1140 return show->obj.head + show->obj.size - data;
1141}
1142
1143/* Is object pointed to by @data of @size already copied to our safe buffer? */
1144static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1145{
1146 return data >= show->obj.data &&
1147 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1148}
1149
1150/*
1151 * If object pointed to by @data of @size falls within our safe buffer, return
1152 * the equivalent pointer to the same safe data. Assumes
1153 * copy_from_kernel_nofault() has already happened and our safe buffer is
1154 * populated.
1155 */
1156static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1157{
1158 if (btf_show_obj_is_safe(show, data, size))
1159 return show->obj.safe + (data - show->obj.data);
1160 return NULL;
1161}
1162
1163/*
1164 * Return a safe-to-access version of data pointed to by @data.
1165 * We do this by copying the relevant amount of information
1166 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1167 *
1168 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1169 * safe copy is needed.
1170 *
1171 * Otherwise we need to determine if we have the required amount
1172 * of data (determined by the @data pointer and the size of the
1173 * largest base type we can encounter (represented by
1174 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1175 * that we will be able to print some of the current object,
1176 * and if more is needed a copy will be triggered.
1177 * Some objects such as structs will not fit into the buffer;
1178 * in such cases additional copies when we iterate over their
1179 * members may be needed.
1180 *
1181 * btf_show_obj_safe() is used to return a safe buffer for
1182 * btf_show_start_type(); this ensures that as we recurse into
1183 * nested types we always have safe data for the given type.
1184 * This approach is somewhat wasteful; it's possible for example
1185 * that when iterating over a large union we'll end up copying the
1186 * same data repeatedly, but the goal is safety not performance.
1187 * We use stack data as opposed to per-CPU buffers because the
1188 * iteration over a type can take some time, and preemption handling
1189 * would greatly complicate use of the safe buffer.
1190 */
1191static void *btf_show_obj_safe(struct btf_show *show,
1192 const struct btf_type *t,
1193 void *data)
1194{
1195 const struct btf_type *rt;
1196 int size_left, size;
1197 void *safe = NULL;
1198
1199 if (show->flags & BTF_SHOW_UNSAFE)
1200 return data;
1201
1202 rt = btf_resolve_size(show->btf, t, &size);
1203 if (IS_ERR(rt)) {
1204 show->state.status = PTR_ERR(rt);
1205 return NULL;
1206 }
1207
1208 /*
1209 * Is this toplevel object? If so, set total object size and
1210 * initialize pointers. Otherwise check if we still fall within
1211 * our safe object data.
1212 */
1213 if (show->state.depth == 0) {
1214 show->obj.size = size;
1215 show->obj.head = data;
1216 } else {
1217 /*
1218 * If the size of the current object is > our remaining
1219 * safe buffer we _may_ need to do a new copy. However
1220 * consider the case of a nested struct; it's size pushes
1221 * us over the safe buffer limit, but showing any individual
1222 * struct members does not. In such cases, we don't need
1223 * to initiate a fresh copy yet; however we definitely need
1224 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1225 * in our buffer, regardless of the current object size.
1226 * The logic here is that as we resolve types we will
1227 * hit a base type at some point, and we need to be sure
1228 * the next chunk of data is safely available to display
1229 * that type info safely. We cannot rely on the size of
1230 * the current object here because it may be much larger
1231 * than our current buffer (e.g. task_struct is 8k).
1232 * All we want to do here is ensure that we can print the
1233 * next basic type, which we can if either
1234 * - the current type size is within the safe buffer; or
1235 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1236 * the safe buffer.
1237 */
1238 safe = __btf_show_obj_safe(show, data,
1239 min(size,
1240 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1241 }
1242
1243 /*
1244 * We need a new copy to our safe object, either because we haven't
1245 * yet copied and are initializing safe data, or because the data
1246 * we want falls outside the boundaries of the safe object.
1247 */
1248 if (!safe) {
1249 size_left = btf_show_obj_size_left(show, data);
1250 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1251 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1252 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1253 data, size_left);
1254 if (!show->state.status) {
1255 show->obj.data = data;
1256 safe = show->obj.safe;
1257 }
1258 }
1259
1260 return safe;
1261}
1262
1263/*
1264 * Set the type we are starting to show and return a safe data pointer
1265 * to be used for showing the associated data.
1266 */
1267static void *btf_show_start_type(struct btf_show *show,
1268 const struct btf_type *t,
1269 u32 type_id, void *data)
1270{
1271 show->state.type = t;
1272 show->state.type_id = type_id;
1273 show->state.name[0] = '\0';
1274
1275 return btf_show_obj_safe(show, t, data);
1276}
1277
1278static void btf_show_end_type(struct btf_show *show)
1279{
1280 show->state.type = NULL;
1281 show->state.type_id = 0;
1282 show->state.name[0] = '\0';
1283}
1284
1285static void *btf_show_start_aggr_type(struct btf_show *show,
1286 const struct btf_type *t,
1287 u32 type_id, void *data)
1288{
1289 void *safe_data = btf_show_start_type(show, t, type_id, data);
1290
1291 if (!safe_data)
1292 return safe_data;
1293
1294 btf_show(show, "%s%s%s", btf_show_indent(show),
1295 btf_show_name(show),
1296 btf_show_newline(show));
1297 show->state.depth++;
1298 return safe_data;
1299}
1300
1301static void btf_show_end_aggr_type(struct btf_show *show,
1302 const char *suffix)
1303{
1304 show->state.depth--;
1305 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1306 btf_show_delim(show), btf_show_newline(show));
1307 btf_show_end_type(show);
1308}
1309
1310static void btf_show_start_member(struct btf_show *show,
1311 const struct btf_member *m)
1312{
1313 show->state.member = m;
1314}
1315
1316static void btf_show_start_array_member(struct btf_show *show)
1317{
1318 show->state.array_member = 1;
1319 btf_show_start_member(show, NULL);
1320}
1321
1322static void btf_show_end_member(struct btf_show *show)
1323{
1324 show->state.member = NULL;
1325}
1326
1327static void btf_show_end_array_member(struct btf_show *show)
1328{
1329 show->state.array_member = 0;
1330 btf_show_end_member(show);
1331}
1332
1333static void *btf_show_start_array_type(struct btf_show *show,
1334 const struct btf_type *t,
1335 u32 type_id,
1336 u16 array_encoding,
1337 void *data)
1338{
1339 show->state.array_encoding = array_encoding;
1340 show->state.array_terminated = 0;
1341 return btf_show_start_aggr_type(show, t, type_id, data);
1342}
1343
1344static void btf_show_end_array_type(struct btf_show *show)
1345{
1346 show->state.array_encoding = 0;
1347 show->state.array_terminated = 0;
1348 btf_show_end_aggr_type(show, "]");
1349}
1350
1351static void *btf_show_start_struct_type(struct btf_show *show,
1352 const struct btf_type *t,
1353 u32 type_id,
1354 void *data)
1355{
1356 return btf_show_start_aggr_type(show, t, type_id, data);
1357}
1358
1359static void btf_show_end_struct_type(struct btf_show *show)
1360{
1361 btf_show_end_aggr_type(show, "}");
1362}
1363
1364__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1365 const char *fmt, ...)
1366{
1367 va_list args;
1368
1369 va_start(args, fmt);
1370 bpf_verifier_vlog(log, fmt, args);
1371 va_end(args);
1372}
1373
1374__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1375 const char *fmt, ...)
1376{
1377 struct bpf_verifier_log *log = &env->log;
1378 va_list args;
1379
1380 if (!bpf_verifier_log_needed(log))
1381 return;
1382
1383 va_start(args, fmt);
1384 bpf_verifier_vlog(log, fmt, args);
1385 va_end(args);
1386}
1387
1388__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1389 const struct btf_type *t,
1390 bool log_details,
1391 const char *fmt, ...)
1392{
1393 struct bpf_verifier_log *log = &env->log;
1394 struct btf *btf = env->btf;
1395 va_list args;
1396
1397 if (!bpf_verifier_log_needed(log))
1398 return;
1399
1400 /* btf verifier prints all types it is processing via
1401 * btf_verifier_log_type(..., fmt = NULL).
1402 * Skip those prints for in-kernel BTF verification.
1403 */
1404 if (log->level == BPF_LOG_KERNEL && !fmt)
1405 return;
1406
1407 __btf_verifier_log(log, "[%u] %s %s%s",
1408 env->log_type_id,
1409 btf_type_str(t),
1410 __btf_name_by_offset(btf, t->name_off),
1411 log_details ? " " : "");
1412
1413 if (log_details)
1414 btf_type_ops(t)->log_details(env, t);
1415
1416 if (fmt && *fmt) {
1417 __btf_verifier_log(log, " ");
1418 va_start(args, fmt);
1419 bpf_verifier_vlog(log, fmt, args);
1420 va_end(args);
1421 }
1422
1423 __btf_verifier_log(log, "\n");
1424}
1425
1426#define btf_verifier_log_type(env, t, ...) \
1427 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1428#define btf_verifier_log_basic(env, t, ...) \
1429 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1430
1431__printf(4, 5)
1432static void btf_verifier_log_member(struct btf_verifier_env *env,
1433 const struct btf_type *struct_type,
1434 const struct btf_member *member,
1435 const char *fmt, ...)
1436{
1437 struct bpf_verifier_log *log = &env->log;
1438 struct btf *btf = env->btf;
1439 va_list args;
1440
1441 if (!bpf_verifier_log_needed(log))
1442 return;
1443
1444 if (log->level == BPF_LOG_KERNEL && !fmt)
1445 return;
1446 /* The CHECK_META phase already did a btf dump.
1447 *
1448 * If member is logged again, it must hit an error in
1449 * parsing this member. It is useful to print out which
1450 * struct this member belongs to.
1451 */
1452 if (env->phase != CHECK_META)
1453 btf_verifier_log_type(env, struct_type, NULL);
1454
1455 if (btf_type_kflag(struct_type))
1456 __btf_verifier_log(log,
1457 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1458 __btf_name_by_offset(btf, member->name_off),
1459 member->type,
1460 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1461 BTF_MEMBER_BIT_OFFSET(member->offset));
1462 else
1463 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1464 __btf_name_by_offset(btf, member->name_off),
1465 member->type, member->offset);
1466
1467 if (fmt && *fmt) {
1468 __btf_verifier_log(log, " ");
1469 va_start(args, fmt);
1470 bpf_verifier_vlog(log, fmt, args);
1471 va_end(args);
1472 }
1473
1474 __btf_verifier_log(log, "\n");
1475}
1476
1477__printf(4, 5)
1478static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1479 const struct btf_type *datasec_type,
1480 const struct btf_var_secinfo *vsi,
1481 const char *fmt, ...)
1482{
1483 struct bpf_verifier_log *log = &env->log;
1484 va_list args;
1485
1486 if (!bpf_verifier_log_needed(log))
1487 return;
1488 if (log->level == BPF_LOG_KERNEL && !fmt)
1489 return;
1490 if (env->phase != CHECK_META)
1491 btf_verifier_log_type(env, datasec_type, NULL);
1492
1493 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1494 vsi->type, vsi->offset, vsi->size);
1495 if (fmt && *fmt) {
1496 __btf_verifier_log(log, " ");
1497 va_start(args, fmt);
1498 bpf_verifier_vlog(log, fmt, args);
1499 va_end(args);
1500 }
1501
1502 __btf_verifier_log(log, "\n");
1503}
1504
1505static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1506 u32 btf_data_size)
1507{
1508 struct bpf_verifier_log *log = &env->log;
1509 const struct btf *btf = env->btf;
1510 const struct btf_header *hdr;
1511
1512 if (!bpf_verifier_log_needed(log))
1513 return;
1514
1515 if (log->level == BPF_LOG_KERNEL)
1516 return;
1517 hdr = &btf->hdr;
1518 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1519 __btf_verifier_log(log, "version: %u\n", hdr->version);
1520 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1521 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1522 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1523 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1524 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1525 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1526 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1527}
1528
1529static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1530{
1531 struct btf *btf = env->btf;
1532
1533 if (btf->types_size == btf->nr_types) {
1534 /* Expand 'types' array */
1535
1536 struct btf_type **new_types;
1537 u32 expand_by, new_size;
1538
1539 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1540 btf_verifier_log(env, "Exceeded max num of types");
1541 return -E2BIG;
1542 }
1543
1544 expand_by = max_t(u32, btf->types_size >> 2, 16);
1545 new_size = min_t(u32, BTF_MAX_TYPE,
1546 btf->types_size + expand_by);
1547
1548 new_types = kvcalloc(new_size, sizeof(*new_types),
1549 GFP_KERNEL | __GFP_NOWARN);
1550 if (!new_types)
1551 return -ENOMEM;
1552
1553 if (btf->nr_types == 0) {
1554 if (!btf->base_btf) {
1555 /* lazily init VOID type */
1556 new_types[0] = &btf_void;
1557 btf->nr_types++;
1558 }
1559 } else {
1560 memcpy(new_types, btf->types,
1561 sizeof(*btf->types) * btf->nr_types);
1562 }
1563
1564 kvfree(btf->types);
1565 btf->types = new_types;
1566 btf->types_size = new_size;
1567 }
1568
1569 btf->types[btf->nr_types++] = t;
1570
1571 return 0;
1572}
1573
1574static int btf_alloc_id(struct btf *btf)
1575{
1576 int id;
1577
1578 idr_preload(GFP_KERNEL);
1579 spin_lock_bh(&btf_idr_lock);
1580 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1581 if (id > 0)
1582 btf->id = id;
1583 spin_unlock_bh(&btf_idr_lock);
1584 idr_preload_end();
1585
1586 if (WARN_ON_ONCE(!id))
1587 return -ENOSPC;
1588
1589 return id > 0 ? 0 : id;
1590}
1591
1592static void btf_free_id(struct btf *btf)
1593{
1594 unsigned long flags;
1595
1596 /*
1597 * In map-in-map, calling map_delete_elem() on outer
1598 * map will call bpf_map_put on the inner map.
1599 * It will then eventually call btf_free_id()
1600 * on the inner map. Some of the map_delete_elem()
1601 * implementation may have irq disabled, so
1602 * we need to use the _irqsave() version instead
1603 * of the _bh() version.
1604 */
1605 spin_lock_irqsave(&btf_idr_lock, flags);
1606 idr_remove(&btf_idr, btf->id);
1607 spin_unlock_irqrestore(&btf_idr_lock, flags);
1608}
1609
1610static void btf_free_kfunc_set_tab(struct btf *btf)
1611{
1612 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1613 int hook;
1614
1615 if (!tab)
1616 return;
1617 /* For module BTF, we directly assign the sets being registered, so
1618 * there is nothing to free except kfunc_set_tab.
1619 */
1620 if (btf_is_module(btf))
1621 goto free_tab;
1622 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1623 kfree(tab->sets[hook]);
1624free_tab:
1625 kfree(tab);
1626 btf->kfunc_set_tab = NULL;
1627}
1628
1629static void btf_free_dtor_kfunc_tab(struct btf *btf)
1630{
1631 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1632
1633 if (!tab)
1634 return;
1635 kfree(tab);
1636 btf->dtor_kfunc_tab = NULL;
1637}
1638
1639static void btf_struct_metas_free(struct btf_struct_metas *tab)
1640{
1641 int i;
1642
1643 if (!tab)
1644 return;
1645 for (i = 0; i < tab->cnt; i++) {
1646 btf_record_free(tab->types[i].record);
1647 kfree(tab->types[i].field_offs);
1648 }
1649 kfree(tab);
1650}
1651
1652static void btf_free_struct_meta_tab(struct btf *btf)
1653{
1654 struct btf_struct_metas *tab = btf->struct_meta_tab;
1655
1656 btf_struct_metas_free(tab);
1657 btf->struct_meta_tab = NULL;
1658}
1659
1660static void btf_free(struct btf *btf)
1661{
1662 btf_free_struct_meta_tab(btf);
1663 btf_free_dtor_kfunc_tab(btf);
1664 btf_free_kfunc_set_tab(btf);
1665 kvfree(btf->types);
1666 kvfree(btf->resolved_sizes);
1667 kvfree(btf->resolved_ids);
1668 kvfree(btf->data);
1669 kfree(btf);
1670}
1671
1672static void btf_free_rcu(struct rcu_head *rcu)
1673{
1674 struct btf *btf = container_of(rcu, struct btf, rcu);
1675
1676 btf_free(btf);
1677}
1678
1679void btf_get(struct btf *btf)
1680{
1681 refcount_inc(&btf->refcnt);
1682}
1683
1684void btf_put(struct btf *btf)
1685{
1686 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1687 btf_free_id(btf);
1688 call_rcu(&btf->rcu, btf_free_rcu);
1689 }
1690}
1691
1692static int env_resolve_init(struct btf_verifier_env *env)
1693{
1694 struct btf *btf = env->btf;
1695 u32 nr_types = btf->nr_types;
1696 u32 *resolved_sizes = NULL;
1697 u32 *resolved_ids = NULL;
1698 u8 *visit_states = NULL;
1699
1700 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1701 GFP_KERNEL | __GFP_NOWARN);
1702 if (!resolved_sizes)
1703 goto nomem;
1704
1705 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1706 GFP_KERNEL | __GFP_NOWARN);
1707 if (!resolved_ids)
1708 goto nomem;
1709
1710 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1711 GFP_KERNEL | __GFP_NOWARN);
1712 if (!visit_states)
1713 goto nomem;
1714
1715 btf->resolved_sizes = resolved_sizes;
1716 btf->resolved_ids = resolved_ids;
1717 env->visit_states = visit_states;
1718
1719 return 0;
1720
1721nomem:
1722 kvfree(resolved_sizes);
1723 kvfree(resolved_ids);
1724 kvfree(visit_states);
1725 return -ENOMEM;
1726}
1727
1728static void btf_verifier_env_free(struct btf_verifier_env *env)
1729{
1730 kvfree(env->visit_states);
1731 kfree(env);
1732}
1733
1734static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1735 const struct btf_type *next_type)
1736{
1737 switch (env->resolve_mode) {
1738 case RESOLVE_TBD:
1739 /* int, enum or void is a sink */
1740 return !btf_type_needs_resolve(next_type);
1741 case RESOLVE_PTR:
1742 /* int, enum, void, struct, array, func or func_proto is a sink
1743 * for ptr
1744 */
1745 return !btf_type_is_modifier(next_type) &&
1746 !btf_type_is_ptr(next_type);
1747 case RESOLVE_STRUCT_OR_ARRAY:
1748 /* int, enum, void, ptr, func or func_proto is a sink
1749 * for struct and array
1750 */
1751 return !btf_type_is_modifier(next_type) &&
1752 !btf_type_is_array(next_type) &&
1753 !btf_type_is_struct(next_type);
1754 default:
1755 BUG();
1756 }
1757}
1758
1759static bool env_type_is_resolved(const struct btf_verifier_env *env,
1760 u32 type_id)
1761{
1762 /* base BTF types should be resolved by now */
1763 if (type_id < env->btf->start_id)
1764 return true;
1765
1766 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1767}
1768
1769static int env_stack_push(struct btf_verifier_env *env,
1770 const struct btf_type *t, u32 type_id)
1771{
1772 const struct btf *btf = env->btf;
1773 struct resolve_vertex *v;
1774
1775 if (env->top_stack == MAX_RESOLVE_DEPTH)
1776 return -E2BIG;
1777
1778 if (type_id < btf->start_id
1779 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1780 return -EEXIST;
1781
1782 env->visit_states[type_id - btf->start_id] = VISITED;
1783
1784 v = &env->stack[env->top_stack++];
1785 v->t = t;
1786 v->type_id = type_id;
1787 v->next_member = 0;
1788
1789 if (env->resolve_mode == RESOLVE_TBD) {
1790 if (btf_type_is_ptr(t))
1791 env->resolve_mode = RESOLVE_PTR;
1792 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1793 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1794 }
1795
1796 return 0;
1797}
1798
1799static void env_stack_set_next_member(struct btf_verifier_env *env,
1800 u16 next_member)
1801{
1802 env->stack[env->top_stack - 1].next_member = next_member;
1803}
1804
1805static void env_stack_pop_resolved(struct btf_verifier_env *env,
1806 u32 resolved_type_id,
1807 u32 resolved_size)
1808{
1809 u32 type_id = env->stack[--(env->top_stack)].type_id;
1810 struct btf *btf = env->btf;
1811
1812 type_id -= btf->start_id; /* adjust to local type id */
1813 btf->resolved_sizes[type_id] = resolved_size;
1814 btf->resolved_ids[type_id] = resolved_type_id;
1815 env->visit_states[type_id] = RESOLVED;
1816}
1817
1818static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1819{
1820 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1821}
1822
1823/* Resolve the size of a passed-in "type"
1824 *
1825 * type: is an array (e.g. u32 array[x][y])
1826 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1827 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1828 * corresponds to the return type.
1829 * *elem_type: u32
1830 * *elem_id: id of u32
1831 * *total_nelems: (x * y). Hence, individual elem size is
1832 * (*type_size / *total_nelems)
1833 * *type_id: id of type if it's changed within the function, 0 if not
1834 *
1835 * type: is not an array (e.g. const struct X)
1836 * return type: type "struct X"
1837 * *type_size: sizeof(struct X)
1838 * *elem_type: same as return type ("struct X")
1839 * *elem_id: 0
1840 * *total_nelems: 1
1841 * *type_id: id of type if it's changed within the function, 0 if not
1842 */
1843static const struct btf_type *
1844__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1845 u32 *type_size, const struct btf_type **elem_type,
1846 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1847{
1848 const struct btf_type *array_type = NULL;
1849 const struct btf_array *array = NULL;
1850 u32 i, size, nelems = 1, id = 0;
1851
1852 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1853 switch (BTF_INFO_KIND(type->info)) {
1854 /* type->size can be used */
1855 case BTF_KIND_INT:
1856 case BTF_KIND_STRUCT:
1857 case BTF_KIND_UNION:
1858 case BTF_KIND_ENUM:
1859 case BTF_KIND_FLOAT:
1860 case BTF_KIND_ENUM64:
1861 size = type->size;
1862 goto resolved;
1863
1864 case BTF_KIND_PTR:
1865 size = sizeof(void *);
1866 goto resolved;
1867
1868 /* Modifiers */
1869 case BTF_KIND_TYPEDEF:
1870 case BTF_KIND_VOLATILE:
1871 case BTF_KIND_CONST:
1872 case BTF_KIND_RESTRICT:
1873 case BTF_KIND_TYPE_TAG:
1874 id = type->type;
1875 type = btf_type_by_id(btf, type->type);
1876 break;
1877
1878 case BTF_KIND_ARRAY:
1879 if (!array_type)
1880 array_type = type;
1881 array = btf_type_array(type);
1882 if (nelems && array->nelems > U32_MAX / nelems)
1883 return ERR_PTR(-EINVAL);
1884 nelems *= array->nelems;
1885 type = btf_type_by_id(btf, array->type);
1886 break;
1887
1888 /* type without size */
1889 default:
1890 return ERR_PTR(-EINVAL);
1891 }
1892 }
1893
1894 return ERR_PTR(-EINVAL);
1895
1896resolved:
1897 if (nelems && size > U32_MAX / nelems)
1898 return ERR_PTR(-EINVAL);
1899
1900 *type_size = nelems * size;
1901 if (total_nelems)
1902 *total_nelems = nelems;
1903 if (elem_type)
1904 *elem_type = type;
1905 if (elem_id)
1906 *elem_id = array ? array->type : 0;
1907 if (type_id && id)
1908 *type_id = id;
1909
1910 return array_type ? : type;
1911}
1912
1913const struct btf_type *
1914btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1915 u32 *type_size)
1916{
1917 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1918}
1919
1920static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1921{
1922 while (type_id < btf->start_id)
1923 btf = btf->base_btf;
1924
1925 return btf->resolved_ids[type_id - btf->start_id];
1926}
1927
1928/* The input param "type_id" must point to a needs_resolve type */
1929static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1930 u32 *type_id)
1931{
1932 *type_id = btf_resolved_type_id(btf, *type_id);
1933 return btf_type_by_id(btf, *type_id);
1934}
1935
1936static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1937{
1938 while (type_id < btf->start_id)
1939 btf = btf->base_btf;
1940
1941 return btf->resolved_sizes[type_id - btf->start_id];
1942}
1943
1944const struct btf_type *btf_type_id_size(const struct btf *btf,
1945 u32 *type_id, u32 *ret_size)
1946{
1947 const struct btf_type *size_type;
1948 u32 size_type_id = *type_id;
1949 u32 size = 0;
1950
1951 size_type = btf_type_by_id(btf, size_type_id);
1952 if (btf_type_nosize_or_null(size_type))
1953 return NULL;
1954
1955 if (btf_type_has_size(size_type)) {
1956 size = size_type->size;
1957 } else if (btf_type_is_array(size_type)) {
1958 size = btf_resolved_type_size(btf, size_type_id);
1959 } else if (btf_type_is_ptr(size_type)) {
1960 size = sizeof(void *);
1961 } else {
1962 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1963 !btf_type_is_var(size_type)))
1964 return NULL;
1965
1966 size_type_id = btf_resolved_type_id(btf, size_type_id);
1967 size_type = btf_type_by_id(btf, size_type_id);
1968 if (btf_type_nosize_or_null(size_type))
1969 return NULL;
1970 else if (btf_type_has_size(size_type))
1971 size = size_type->size;
1972 else if (btf_type_is_array(size_type))
1973 size = btf_resolved_type_size(btf, size_type_id);
1974 else if (btf_type_is_ptr(size_type))
1975 size = sizeof(void *);
1976 else
1977 return NULL;
1978 }
1979
1980 *type_id = size_type_id;
1981 if (ret_size)
1982 *ret_size = size;
1983
1984 return size_type;
1985}
1986
1987static int btf_df_check_member(struct btf_verifier_env *env,
1988 const struct btf_type *struct_type,
1989 const struct btf_member *member,
1990 const struct btf_type *member_type)
1991{
1992 btf_verifier_log_basic(env, struct_type,
1993 "Unsupported check_member");
1994 return -EINVAL;
1995}
1996
1997static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1998 const struct btf_type *struct_type,
1999 const struct btf_member *member,
2000 const struct btf_type *member_type)
2001{
2002 btf_verifier_log_basic(env, struct_type,
2003 "Unsupported check_kflag_member");
2004 return -EINVAL;
2005}
2006
2007/* Used for ptr, array struct/union and float type members.
2008 * int, enum and modifier types have their specific callback functions.
2009 */
2010static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
2011 const struct btf_type *struct_type,
2012 const struct btf_member *member,
2013 const struct btf_type *member_type)
2014{
2015 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2016 btf_verifier_log_member(env, struct_type, member,
2017 "Invalid member bitfield_size");
2018 return -EINVAL;
2019 }
2020
2021 /* bitfield size is 0, so member->offset represents bit offset only.
2022 * It is safe to call non kflag check_member variants.
2023 */
2024 return btf_type_ops(member_type)->check_member(env, struct_type,
2025 member,
2026 member_type);
2027}
2028
2029static int btf_df_resolve(struct btf_verifier_env *env,
2030 const struct resolve_vertex *v)
2031{
2032 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2033 return -EINVAL;
2034}
2035
2036static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2037 u32 type_id, void *data, u8 bits_offsets,
2038 struct btf_show *show)
2039{
2040 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2041}
2042
2043static int btf_int_check_member(struct btf_verifier_env *env,
2044 const struct btf_type *struct_type,
2045 const struct btf_member *member,
2046 const struct btf_type *member_type)
2047{
2048 u32 int_data = btf_type_int(member_type);
2049 u32 struct_bits_off = member->offset;
2050 u32 struct_size = struct_type->size;
2051 u32 nr_copy_bits;
2052 u32 bytes_offset;
2053
2054 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2055 btf_verifier_log_member(env, struct_type, member,
2056 "bits_offset exceeds U32_MAX");
2057 return -EINVAL;
2058 }
2059
2060 struct_bits_off += BTF_INT_OFFSET(int_data);
2061 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2062 nr_copy_bits = BTF_INT_BITS(int_data) +
2063 BITS_PER_BYTE_MASKED(struct_bits_off);
2064
2065 if (nr_copy_bits > BITS_PER_U128) {
2066 btf_verifier_log_member(env, struct_type, member,
2067 "nr_copy_bits exceeds 128");
2068 return -EINVAL;
2069 }
2070
2071 if (struct_size < bytes_offset ||
2072 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2073 btf_verifier_log_member(env, struct_type, member,
2074 "Member exceeds struct_size");
2075 return -EINVAL;
2076 }
2077
2078 return 0;
2079}
2080
2081static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2082 const struct btf_type *struct_type,
2083 const struct btf_member *member,
2084 const struct btf_type *member_type)
2085{
2086 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2087 u32 int_data = btf_type_int(member_type);
2088 u32 struct_size = struct_type->size;
2089 u32 nr_copy_bits;
2090
2091 /* a regular int type is required for the kflag int member */
2092 if (!btf_type_int_is_regular(member_type)) {
2093 btf_verifier_log_member(env, struct_type, member,
2094 "Invalid member base type");
2095 return -EINVAL;
2096 }
2097
2098 /* check sanity of bitfield size */
2099 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2100 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2101 nr_int_data_bits = BTF_INT_BITS(int_data);
2102 if (!nr_bits) {
2103 /* Not a bitfield member, member offset must be at byte
2104 * boundary.
2105 */
2106 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2107 btf_verifier_log_member(env, struct_type, member,
2108 "Invalid member offset");
2109 return -EINVAL;
2110 }
2111
2112 nr_bits = nr_int_data_bits;
2113 } else if (nr_bits > nr_int_data_bits) {
2114 btf_verifier_log_member(env, struct_type, member,
2115 "Invalid member bitfield_size");
2116 return -EINVAL;
2117 }
2118
2119 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2120 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2121 if (nr_copy_bits > BITS_PER_U128) {
2122 btf_verifier_log_member(env, struct_type, member,
2123 "nr_copy_bits exceeds 128");
2124 return -EINVAL;
2125 }
2126
2127 if (struct_size < bytes_offset ||
2128 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2129 btf_verifier_log_member(env, struct_type, member,
2130 "Member exceeds struct_size");
2131 return -EINVAL;
2132 }
2133
2134 return 0;
2135}
2136
2137static s32 btf_int_check_meta(struct btf_verifier_env *env,
2138 const struct btf_type *t,
2139 u32 meta_left)
2140{
2141 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2142 u16 encoding;
2143
2144 if (meta_left < meta_needed) {
2145 btf_verifier_log_basic(env, t,
2146 "meta_left:%u meta_needed:%u",
2147 meta_left, meta_needed);
2148 return -EINVAL;
2149 }
2150
2151 if (btf_type_vlen(t)) {
2152 btf_verifier_log_type(env, t, "vlen != 0");
2153 return -EINVAL;
2154 }
2155
2156 if (btf_type_kflag(t)) {
2157 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2158 return -EINVAL;
2159 }
2160
2161 int_data = btf_type_int(t);
2162 if (int_data & ~BTF_INT_MASK) {
2163 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2164 int_data);
2165 return -EINVAL;
2166 }
2167
2168 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2169
2170 if (nr_bits > BITS_PER_U128) {
2171 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2172 BITS_PER_U128);
2173 return -EINVAL;
2174 }
2175
2176 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2177 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2178 return -EINVAL;
2179 }
2180
2181 /*
2182 * Only one of the encoding bits is allowed and it
2183 * should be sufficient for the pretty print purpose (i.e. decoding).
2184 * Multiple bits can be allowed later if it is found
2185 * to be insufficient.
2186 */
2187 encoding = BTF_INT_ENCODING(int_data);
2188 if (encoding &&
2189 encoding != BTF_INT_SIGNED &&
2190 encoding != BTF_INT_CHAR &&
2191 encoding != BTF_INT_BOOL) {
2192 btf_verifier_log_type(env, t, "Unsupported encoding");
2193 return -ENOTSUPP;
2194 }
2195
2196 btf_verifier_log_type(env, t, NULL);
2197
2198 return meta_needed;
2199}
2200
2201static void btf_int_log(struct btf_verifier_env *env,
2202 const struct btf_type *t)
2203{
2204 int int_data = btf_type_int(t);
2205
2206 btf_verifier_log(env,
2207 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2208 t->size, BTF_INT_OFFSET(int_data),
2209 BTF_INT_BITS(int_data),
2210 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2211}
2212
2213static void btf_int128_print(struct btf_show *show, void *data)
2214{
2215 /* data points to a __int128 number.
2216 * Suppose
2217 * int128_num = *(__int128 *)data;
2218 * The below formulas shows what upper_num and lower_num represents:
2219 * upper_num = int128_num >> 64;
2220 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2221 */
2222 u64 upper_num, lower_num;
2223
2224#ifdef __BIG_ENDIAN_BITFIELD
2225 upper_num = *(u64 *)data;
2226 lower_num = *(u64 *)(data + 8);
2227#else
2228 upper_num = *(u64 *)(data + 8);
2229 lower_num = *(u64 *)data;
2230#endif
2231 if (upper_num == 0)
2232 btf_show_type_value(show, "0x%llx", lower_num);
2233 else
2234 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2235 lower_num);
2236}
2237
2238static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2239 u16 right_shift_bits)
2240{
2241 u64 upper_num, lower_num;
2242
2243#ifdef __BIG_ENDIAN_BITFIELD
2244 upper_num = print_num[0];
2245 lower_num = print_num[1];
2246#else
2247 upper_num = print_num[1];
2248 lower_num = print_num[0];
2249#endif
2250
2251 /* shake out un-needed bits by shift/or operations */
2252 if (left_shift_bits >= 64) {
2253 upper_num = lower_num << (left_shift_bits - 64);
2254 lower_num = 0;
2255 } else {
2256 upper_num = (upper_num << left_shift_bits) |
2257 (lower_num >> (64 - left_shift_bits));
2258 lower_num = lower_num << left_shift_bits;
2259 }
2260
2261 if (right_shift_bits >= 64) {
2262 lower_num = upper_num >> (right_shift_bits - 64);
2263 upper_num = 0;
2264 } else {
2265 lower_num = (lower_num >> right_shift_bits) |
2266 (upper_num << (64 - right_shift_bits));
2267 upper_num = upper_num >> right_shift_bits;
2268 }
2269
2270#ifdef __BIG_ENDIAN_BITFIELD
2271 print_num[0] = upper_num;
2272 print_num[1] = lower_num;
2273#else
2274 print_num[0] = lower_num;
2275 print_num[1] = upper_num;
2276#endif
2277}
2278
2279static void btf_bitfield_show(void *data, u8 bits_offset,
2280 u8 nr_bits, struct btf_show *show)
2281{
2282 u16 left_shift_bits, right_shift_bits;
2283 u8 nr_copy_bytes;
2284 u8 nr_copy_bits;
2285 u64 print_num[2] = {};
2286
2287 nr_copy_bits = nr_bits + bits_offset;
2288 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2289
2290 memcpy(print_num, data, nr_copy_bytes);
2291
2292#ifdef __BIG_ENDIAN_BITFIELD
2293 left_shift_bits = bits_offset;
2294#else
2295 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2296#endif
2297 right_shift_bits = BITS_PER_U128 - nr_bits;
2298
2299 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2300 btf_int128_print(show, print_num);
2301}
2302
2303
2304static void btf_int_bits_show(const struct btf *btf,
2305 const struct btf_type *t,
2306 void *data, u8 bits_offset,
2307 struct btf_show *show)
2308{
2309 u32 int_data = btf_type_int(t);
2310 u8 nr_bits = BTF_INT_BITS(int_data);
2311 u8 total_bits_offset;
2312
2313 /*
2314 * bits_offset is at most 7.
2315 * BTF_INT_OFFSET() cannot exceed 128 bits.
2316 */
2317 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2318 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2319 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2320 btf_bitfield_show(data, bits_offset, nr_bits, show);
2321}
2322
2323static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2324 u32 type_id, void *data, u8 bits_offset,
2325 struct btf_show *show)
2326{
2327 u32 int_data = btf_type_int(t);
2328 u8 encoding = BTF_INT_ENCODING(int_data);
2329 bool sign = encoding & BTF_INT_SIGNED;
2330 u8 nr_bits = BTF_INT_BITS(int_data);
2331 void *safe_data;
2332
2333 safe_data = btf_show_start_type(show, t, type_id, data);
2334 if (!safe_data)
2335 return;
2336
2337 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2338 BITS_PER_BYTE_MASKED(nr_bits)) {
2339 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2340 goto out;
2341 }
2342
2343 switch (nr_bits) {
2344 case 128:
2345 btf_int128_print(show, safe_data);
2346 break;
2347 case 64:
2348 if (sign)
2349 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2350 else
2351 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2352 break;
2353 case 32:
2354 if (sign)
2355 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2356 else
2357 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2358 break;
2359 case 16:
2360 if (sign)
2361 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2362 else
2363 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2364 break;
2365 case 8:
2366 if (show->state.array_encoding == BTF_INT_CHAR) {
2367 /* check for null terminator */
2368 if (show->state.array_terminated)
2369 break;
2370 if (*(char *)data == '\0') {
2371 show->state.array_terminated = 1;
2372 break;
2373 }
2374 if (isprint(*(char *)data)) {
2375 btf_show_type_value(show, "'%c'",
2376 *(char *)safe_data);
2377 break;
2378 }
2379 }
2380 if (sign)
2381 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2382 else
2383 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2384 break;
2385 default:
2386 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2387 break;
2388 }
2389out:
2390 btf_show_end_type(show);
2391}
2392
2393static const struct btf_kind_operations int_ops = {
2394 .check_meta = btf_int_check_meta,
2395 .resolve = btf_df_resolve,
2396 .check_member = btf_int_check_member,
2397 .check_kflag_member = btf_int_check_kflag_member,
2398 .log_details = btf_int_log,
2399 .show = btf_int_show,
2400};
2401
2402static int btf_modifier_check_member(struct btf_verifier_env *env,
2403 const struct btf_type *struct_type,
2404 const struct btf_member *member,
2405 const struct btf_type *member_type)
2406{
2407 const struct btf_type *resolved_type;
2408 u32 resolved_type_id = member->type;
2409 struct btf_member resolved_member;
2410 struct btf *btf = env->btf;
2411
2412 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2413 if (!resolved_type) {
2414 btf_verifier_log_member(env, struct_type, member,
2415 "Invalid member");
2416 return -EINVAL;
2417 }
2418
2419 resolved_member = *member;
2420 resolved_member.type = resolved_type_id;
2421
2422 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2423 &resolved_member,
2424 resolved_type);
2425}
2426
2427static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2428 const struct btf_type *struct_type,
2429 const struct btf_member *member,
2430 const struct btf_type *member_type)
2431{
2432 const struct btf_type *resolved_type;
2433 u32 resolved_type_id = member->type;
2434 struct btf_member resolved_member;
2435 struct btf *btf = env->btf;
2436
2437 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2438 if (!resolved_type) {
2439 btf_verifier_log_member(env, struct_type, member,
2440 "Invalid member");
2441 return -EINVAL;
2442 }
2443
2444 resolved_member = *member;
2445 resolved_member.type = resolved_type_id;
2446
2447 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2448 &resolved_member,
2449 resolved_type);
2450}
2451
2452static int btf_ptr_check_member(struct btf_verifier_env *env,
2453 const struct btf_type *struct_type,
2454 const struct btf_member *member,
2455 const struct btf_type *member_type)
2456{
2457 u32 struct_size, struct_bits_off, bytes_offset;
2458
2459 struct_size = struct_type->size;
2460 struct_bits_off = member->offset;
2461 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2462
2463 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2464 btf_verifier_log_member(env, struct_type, member,
2465 "Member is not byte aligned");
2466 return -EINVAL;
2467 }
2468
2469 if (struct_size - bytes_offset < sizeof(void *)) {
2470 btf_verifier_log_member(env, struct_type, member,
2471 "Member exceeds struct_size");
2472 return -EINVAL;
2473 }
2474
2475 return 0;
2476}
2477
2478static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2479 const struct btf_type *t,
2480 u32 meta_left)
2481{
2482 const char *value;
2483
2484 if (btf_type_vlen(t)) {
2485 btf_verifier_log_type(env, t, "vlen != 0");
2486 return -EINVAL;
2487 }
2488
2489 if (btf_type_kflag(t)) {
2490 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2491 return -EINVAL;
2492 }
2493
2494 if (!BTF_TYPE_ID_VALID(t->type)) {
2495 btf_verifier_log_type(env, t, "Invalid type_id");
2496 return -EINVAL;
2497 }
2498
2499 /* typedef/type_tag type must have a valid name, and other ref types,
2500 * volatile, const, restrict, should have a null name.
2501 */
2502 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2503 if (!t->name_off ||
2504 !btf_name_valid_identifier(env->btf, t->name_off)) {
2505 btf_verifier_log_type(env, t, "Invalid name");
2506 return -EINVAL;
2507 }
2508 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2509 value = btf_name_by_offset(env->btf, t->name_off);
2510 if (!value || !value[0]) {
2511 btf_verifier_log_type(env, t, "Invalid name");
2512 return -EINVAL;
2513 }
2514 } else {
2515 if (t->name_off) {
2516 btf_verifier_log_type(env, t, "Invalid name");
2517 return -EINVAL;
2518 }
2519 }
2520
2521 btf_verifier_log_type(env, t, NULL);
2522
2523 return 0;
2524}
2525
2526static int btf_modifier_resolve(struct btf_verifier_env *env,
2527 const struct resolve_vertex *v)
2528{
2529 const struct btf_type *t = v->t;
2530 const struct btf_type *next_type;
2531 u32 next_type_id = t->type;
2532 struct btf *btf = env->btf;
2533
2534 next_type = btf_type_by_id(btf, next_type_id);
2535 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2536 btf_verifier_log_type(env, v->t, "Invalid type_id");
2537 return -EINVAL;
2538 }
2539
2540 if (!env_type_is_resolve_sink(env, next_type) &&
2541 !env_type_is_resolved(env, next_type_id))
2542 return env_stack_push(env, next_type, next_type_id);
2543
2544 /* Figure out the resolved next_type_id with size.
2545 * They will be stored in the current modifier's
2546 * resolved_ids and resolved_sizes such that it can
2547 * save us a few type-following when we use it later (e.g. in
2548 * pretty print).
2549 */
2550 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2551 if (env_type_is_resolved(env, next_type_id))
2552 next_type = btf_type_id_resolve(btf, &next_type_id);
2553
2554 /* "typedef void new_void", "const void"...etc */
2555 if (!btf_type_is_void(next_type) &&
2556 !btf_type_is_fwd(next_type) &&
2557 !btf_type_is_func_proto(next_type)) {
2558 btf_verifier_log_type(env, v->t, "Invalid type_id");
2559 return -EINVAL;
2560 }
2561 }
2562
2563 env_stack_pop_resolved(env, next_type_id, 0);
2564
2565 return 0;
2566}
2567
2568static int btf_var_resolve(struct btf_verifier_env *env,
2569 const struct resolve_vertex *v)
2570{
2571 const struct btf_type *next_type;
2572 const struct btf_type *t = v->t;
2573 u32 next_type_id = t->type;
2574 struct btf *btf = env->btf;
2575
2576 next_type = btf_type_by_id(btf, next_type_id);
2577 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2578 btf_verifier_log_type(env, v->t, "Invalid type_id");
2579 return -EINVAL;
2580 }
2581
2582 if (!env_type_is_resolve_sink(env, next_type) &&
2583 !env_type_is_resolved(env, next_type_id))
2584 return env_stack_push(env, next_type, next_type_id);
2585
2586 if (btf_type_is_modifier(next_type)) {
2587 const struct btf_type *resolved_type;
2588 u32 resolved_type_id;
2589
2590 resolved_type_id = next_type_id;
2591 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2592
2593 if (btf_type_is_ptr(resolved_type) &&
2594 !env_type_is_resolve_sink(env, resolved_type) &&
2595 !env_type_is_resolved(env, resolved_type_id))
2596 return env_stack_push(env, resolved_type,
2597 resolved_type_id);
2598 }
2599
2600 /* We must resolve to something concrete at this point, no
2601 * forward types or similar that would resolve to size of
2602 * zero is allowed.
2603 */
2604 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2605 btf_verifier_log_type(env, v->t, "Invalid type_id");
2606 return -EINVAL;
2607 }
2608
2609 env_stack_pop_resolved(env, next_type_id, 0);
2610
2611 return 0;
2612}
2613
2614static int btf_ptr_resolve(struct btf_verifier_env *env,
2615 const struct resolve_vertex *v)
2616{
2617 const struct btf_type *next_type;
2618 const struct btf_type *t = v->t;
2619 u32 next_type_id = t->type;
2620 struct btf *btf = env->btf;
2621
2622 next_type = btf_type_by_id(btf, next_type_id);
2623 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2624 btf_verifier_log_type(env, v->t, "Invalid type_id");
2625 return -EINVAL;
2626 }
2627
2628 if (!env_type_is_resolve_sink(env, next_type) &&
2629 !env_type_is_resolved(env, next_type_id))
2630 return env_stack_push(env, next_type, next_type_id);
2631
2632 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2633 * the modifier may have stopped resolving when it was resolved
2634 * to a ptr (last-resolved-ptr).
2635 *
2636 * We now need to continue from the last-resolved-ptr to
2637 * ensure the last-resolved-ptr will not referring back to
2638 * the current ptr (t).
2639 */
2640 if (btf_type_is_modifier(next_type)) {
2641 const struct btf_type *resolved_type;
2642 u32 resolved_type_id;
2643
2644 resolved_type_id = next_type_id;
2645 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2646
2647 if (btf_type_is_ptr(resolved_type) &&
2648 !env_type_is_resolve_sink(env, resolved_type) &&
2649 !env_type_is_resolved(env, resolved_type_id))
2650 return env_stack_push(env, resolved_type,
2651 resolved_type_id);
2652 }
2653
2654 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2655 if (env_type_is_resolved(env, next_type_id))
2656 next_type = btf_type_id_resolve(btf, &next_type_id);
2657
2658 if (!btf_type_is_void(next_type) &&
2659 !btf_type_is_fwd(next_type) &&
2660 !btf_type_is_func_proto(next_type)) {
2661 btf_verifier_log_type(env, v->t, "Invalid type_id");
2662 return -EINVAL;
2663 }
2664 }
2665
2666 env_stack_pop_resolved(env, next_type_id, 0);
2667
2668 return 0;
2669}
2670
2671static void btf_modifier_show(const struct btf *btf,
2672 const struct btf_type *t,
2673 u32 type_id, void *data,
2674 u8 bits_offset, struct btf_show *show)
2675{
2676 if (btf->resolved_ids)
2677 t = btf_type_id_resolve(btf, &type_id);
2678 else
2679 t = btf_type_skip_modifiers(btf, type_id, NULL);
2680
2681 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2682}
2683
2684static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2685 u32 type_id, void *data, u8 bits_offset,
2686 struct btf_show *show)
2687{
2688 t = btf_type_id_resolve(btf, &type_id);
2689
2690 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2691}
2692
2693static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2694 u32 type_id, void *data, u8 bits_offset,
2695 struct btf_show *show)
2696{
2697 void *safe_data;
2698
2699 safe_data = btf_show_start_type(show, t, type_id, data);
2700 if (!safe_data)
2701 return;
2702
2703 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2704 if (show->flags & BTF_SHOW_PTR_RAW)
2705 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2706 else
2707 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2708 btf_show_end_type(show);
2709}
2710
2711static void btf_ref_type_log(struct btf_verifier_env *env,
2712 const struct btf_type *t)
2713{
2714 btf_verifier_log(env, "type_id=%u", t->type);
2715}
2716
2717static struct btf_kind_operations modifier_ops = {
2718 .check_meta = btf_ref_type_check_meta,
2719 .resolve = btf_modifier_resolve,
2720 .check_member = btf_modifier_check_member,
2721 .check_kflag_member = btf_modifier_check_kflag_member,
2722 .log_details = btf_ref_type_log,
2723 .show = btf_modifier_show,
2724};
2725
2726static struct btf_kind_operations ptr_ops = {
2727 .check_meta = btf_ref_type_check_meta,
2728 .resolve = btf_ptr_resolve,
2729 .check_member = btf_ptr_check_member,
2730 .check_kflag_member = btf_generic_check_kflag_member,
2731 .log_details = btf_ref_type_log,
2732 .show = btf_ptr_show,
2733};
2734
2735static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2736 const struct btf_type *t,
2737 u32 meta_left)
2738{
2739 if (btf_type_vlen(t)) {
2740 btf_verifier_log_type(env, t, "vlen != 0");
2741 return -EINVAL;
2742 }
2743
2744 if (t->type) {
2745 btf_verifier_log_type(env, t, "type != 0");
2746 return -EINVAL;
2747 }
2748
2749 /* fwd type must have a valid name */
2750 if (!t->name_off ||
2751 !btf_name_valid_identifier(env->btf, t->name_off)) {
2752 btf_verifier_log_type(env, t, "Invalid name");
2753 return -EINVAL;
2754 }
2755
2756 btf_verifier_log_type(env, t, NULL);
2757
2758 return 0;
2759}
2760
2761static void btf_fwd_type_log(struct btf_verifier_env *env,
2762 const struct btf_type *t)
2763{
2764 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2765}
2766
2767static struct btf_kind_operations fwd_ops = {
2768 .check_meta = btf_fwd_check_meta,
2769 .resolve = btf_df_resolve,
2770 .check_member = btf_df_check_member,
2771 .check_kflag_member = btf_df_check_kflag_member,
2772 .log_details = btf_fwd_type_log,
2773 .show = btf_df_show,
2774};
2775
2776static int btf_array_check_member(struct btf_verifier_env *env,
2777 const struct btf_type *struct_type,
2778 const struct btf_member *member,
2779 const struct btf_type *member_type)
2780{
2781 u32 struct_bits_off = member->offset;
2782 u32 struct_size, bytes_offset;
2783 u32 array_type_id, array_size;
2784 struct btf *btf = env->btf;
2785
2786 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2787 btf_verifier_log_member(env, struct_type, member,
2788 "Member is not byte aligned");
2789 return -EINVAL;
2790 }
2791
2792 array_type_id = member->type;
2793 btf_type_id_size(btf, &array_type_id, &array_size);
2794 struct_size = struct_type->size;
2795 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2796 if (struct_size - bytes_offset < array_size) {
2797 btf_verifier_log_member(env, struct_type, member,
2798 "Member exceeds struct_size");
2799 return -EINVAL;
2800 }
2801
2802 return 0;
2803}
2804
2805static s32 btf_array_check_meta(struct btf_verifier_env *env,
2806 const struct btf_type *t,
2807 u32 meta_left)
2808{
2809 const struct btf_array *array = btf_type_array(t);
2810 u32 meta_needed = sizeof(*array);
2811
2812 if (meta_left < meta_needed) {
2813 btf_verifier_log_basic(env, t,
2814 "meta_left:%u meta_needed:%u",
2815 meta_left, meta_needed);
2816 return -EINVAL;
2817 }
2818
2819 /* array type should not have a name */
2820 if (t->name_off) {
2821 btf_verifier_log_type(env, t, "Invalid name");
2822 return -EINVAL;
2823 }
2824
2825 if (btf_type_vlen(t)) {
2826 btf_verifier_log_type(env, t, "vlen != 0");
2827 return -EINVAL;
2828 }
2829
2830 if (btf_type_kflag(t)) {
2831 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2832 return -EINVAL;
2833 }
2834
2835 if (t->size) {
2836 btf_verifier_log_type(env, t, "size != 0");
2837 return -EINVAL;
2838 }
2839
2840 /* Array elem type and index type cannot be in type void,
2841 * so !array->type and !array->index_type are not allowed.
2842 */
2843 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2844 btf_verifier_log_type(env, t, "Invalid elem");
2845 return -EINVAL;
2846 }
2847
2848 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2849 btf_verifier_log_type(env, t, "Invalid index");
2850 return -EINVAL;
2851 }
2852
2853 btf_verifier_log_type(env, t, NULL);
2854
2855 return meta_needed;
2856}
2857
2858static int btf_array_resolve(struct btf_verifier_env *env,
2859 const struct resolve_vertex *v)
2860{
2861 const struct btf_array *array = btf_type_array(v->t);
2862 const struct btf_type *elem_type, *index_type;
2863 u32 elem_type_id, index_type_id;
2864 struct btf *btf = env->btf;
2865 u32 elem_size;
2866
2867 /* Check array->index_type */
2868 index_type_id = array->index_type;
2869 index_type = btf_type_by_id(btf, index_type_id);
2870 if (btf_type_nosize_or_null(index_type) ||
2871 btf_type_is_resolve_source_only(index_type)) {
2872 btf_verifier_log_type(env, v->t, "Invalid index");
2873 return -EINVAL;
2874 }
2875
2876 if (!env_type_is_resolve_sink(env, index_type) &&
2877 !env_type_is_resolved(env, index_type_id))
2878 return env_stack_push(env, index_type, index_type_id);
2879
2880 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2881 if (!index_type || !btf_type_is_int(index_type) ||
2882 !btf_type_int_is_regular(index_type)) {
2883 btf_verifier_log_type(env, v->t, "Invalid index");
2884 return -EINVAL;
2885 }
2886
2887 /* Check array->type */
2888 elem_type_id = array->type;
2889 elem_type = btf_type_by_id(btf, elem_type_id);
2890 if (btf_type_nosize_or_null(elem_type) ||
2891 btf_type_is_resolve_source_only(elem_type)) {
2892 btf_verifier_log_type(env, v->t,
2893 "Invalid elem");
2894 return -EINVAL;
2895 }
2896
2897 if (!env_type_is_resolve_sink(env, elem_type) &&
2898 !env_type_is_resolved(env, elem_type_id))
2899 return env_stack_push(env, elem_type, elem_type_id);
2900
2901 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2902 if (!elem_type) {
2903 btf_verifier_log_type(env, v->t, "Invalid elem");
2904 return -EINVAL;
2905 }
2906
2907 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2908 btf_verifier_log_type(env, v->t, "Invalid array of int");
2909 return -EINVAL;
2910 }
2911
2912 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2913 btf_verifier_log_type(env, v->t,
2914 "Array size overflows U32_MAX");
2915 return -EINVAL;
2916 }
2917
2918 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2919
2920 return 0;
2921}
2922
2923static void btf_array_log(struct btf_verifier_env *env,
2924 const struct btf_type *t)
2925{
2926 const struct btf_array *array = btf_type_array(t);
2927
2928 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2929 array->type, array->index_type, array->nelems);
2930}
2931
2932static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2933 u32 type_id, void *data, u8 bits_offset,
2934 struct btf_show *show)
2935{
2936 const struct btf_array *array = btf_type_array(t);
2937 const struct btf_kind_operations *elem_ops;
2938 const struct btf_type *elem_type;
2939 u32 i, elem_size = 0, elem_type_id;
2940 u16 encoding = 0;
2941
2942 elem_type_id = array->type;
2943 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2944 if (elem_type && btf_type_has_size(elem_type))
2945 elem_size = elem_type->size;
2946
2947 if (elem_type && btf_type_is_int(elem_type)) {
2948 u32 int_type = btf_type_int(elem_type);
2949
2950 encoding = BTF_INT_ENCODING(int_type);
2951
2952 /*
2953 * BTF_INT_CHAR encoding never seems to be set for
2954 * char arrays, so if size is 1 and element is
2955 * printable as a char, we'll do that.
2956 */
2957 if (elem_size == 1)
2958 encoding = BTF_INT_CHAR;
2959 }
2960
2961 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2962 return;
2963
2964 if (!elem_type)
2965 goto out;
2966 elem_ops = btf_type_ops(elem_type);
2967
2968 for (i = 0; i < array->nelems; i++) {
2969
2970 btf_show_start_array_member(show);
2971
2972 elem_ops->show(btf, elem_type, elem_type_id, data,
2973 bits_offset, show);
2974 data += elem_size;
2975
2976 btf_show_end_array_member(show);
2977
2978 if (show->state.array_terminated)
2979 break;
2980 }
2981out:
2982 btf_show_end_array_type(show);
2983}
2984
2985static void btf_array_show(const struct btf *btf, const struct btf_type *t,
2986 u32 type_id, void *data, u8 bits_offset,
2987 struct btf_show *show)
2988{
2989 const struct btf_member *m = show->state.member;
2990
2991 /*
2992 * First check if any members would be shown (are non-zero).
2993 * See comments above "struct btf_show" definition for more
2994 * details on how this works at a high-level.
2995 */
2996 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
2997 if (!show->state.depth_check) {
2998 show->state.depth_check = show->state.depth + 1;
2999 show->state.depth_to_show = 0;
3000 }
3001 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3002 show->state.member = m;
3003
3004 if (show->state.depth_check != show->state.depth + 1)
3005 return;
3006 show->state.depth_check = 0;
3007
3008 if (show->state.depth_to_show <= show->state.depth)
3009 return;
3010 /*
3011 * Reaching here indicates we have recursed and found
3012 * non-zero array member(s).
3013 */
3014 }
3015 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3016}
3017
3018static struct btf_kind_operations array_ops = {
3019 .check_meta = btf_array_check_meta,
3020 .resolve = btf_array_resolve,
3021 .check_member = btf_array_check_member,
3022 .check_kflag_member = btf_generic_check_kflag_member,
3023 .log_details = btf_array_log,
3024 .show = btf_array_show,
3025};
3026
3027static int btf_struct_check_member(struct btf_verifier_env *env,
3028 const struct btf_type *struct_type,
3029 const struct btf_member *member,
3030 const struct btf_type *member_type)
3031{
3032 u32 struct_bits_off = member->offset;
3033 u32 struct_size, bytes_offset;
3034
3035 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3036 btf_verifier_log_member(env, struct_type, member,
3037 "Member is not byte aligned");
3038 return -EINVAL;
3039 }
3040
3041 struct_size = struct_type->size;
3042 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3043 if (struct_size - bytes_offset < member_type->size) {
3044 btf_verifier_log_member(env, struct_type, member,
3045 "Member exceeds struct_size");
3046 return -EINVAL;
3047 }
3048
3049 return 0;
3050}
3051
3052static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3053 const struct btf_type *t,
3054 u32 meta_left)
3055{
3056 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3057 const struct btf_member *member;
3058 u32 meta_needed, last_offset;
3059 struct btf *btf = env->btf;
3060 u32 struct_size = t->size;
3061 u32 offset;
3062 u16 i;
3063
3064 meta_needed = btf_type_vlen(t) * sizeof(*member);
3065 if (meta_left < meta_needed) {
3066 btf_verifier_log_basic(env, t,
3067 "meta_left:%u meta_needed:%u",
3068 meta_left, meta_needed);
3069 return -EINVAL;
3070 }
3071
3072 /* struct type either no name or a valid one */
3073 if (t->name_off &&
3074 !btf_name_valid_identifier(env->btf, t->name_off)) {
3075 btf_verifier_log_type(env, t, "Invalid name");
3076 return -EINVAL;
3077 }
3078
3079 btf_verifier_log_type(env, t, NULL);
3080
3081 last_offset = 0;
3082 for_each_member(i, t, member) {
3083 if (!btf_name_offset_valid(btf, member->name_off)) {
3084 btf_verifier_log_member(env, t, member,
3085 "Invalid member name_offset:%u",
3086 member->name_off);
3087 return -EINVAL;
3088 }
3089
3090 /* struct member either no name or a valid one */
3091 if (member->name_off &&
3092 !btf_name_valid_identifier(btf, member->name_off)) {
3093 btf_verifier_log_member(env, t, member, "Invalid name");
3094 return -EINVAL;
3095 }
3096 /* A member cannot be in type void */
3097 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3098 btf_verifier_log_member(env, t, member,
3099 "Invalid type_id");
3100 return -EINVAL;
3101 }
3102
3103 offset = __btf_member_bit_offset(t, member);
3104 if (is_union && offset) {
3105 btf_verifier_log_member(env, t, member,
3106 "Invalid member bits_offset");
3107 return -EINVAL;
3108 }
3109
3110 /*
3111 * ">" instead of ">=" because the last member could be
3112 * "char a[0];"
3113 */
3114 if (last_offset > offset) {
3115 btf_verifier_log_member(env, t, member,
3116 "Invalid member bits_offset");
3117 return -EINVAL;
3118 }
3119
3120 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3121 btf_verifier_log_member(env, t, member,
3122 "Member bits_offset exceeds its struct size");
3123 return -EINVAL;
3124 }
3125
3126 btf_verifier_log_member(env, t, member, NULL);
3127 last_offset = offset;
3128 }
3129
3130 return meta_needed;
3131}
3132
3133static int btf_struct_resolve(struct btf_verifier_env *env,
3134 const struct resolve_vertex *v)
3135{
3136 const struct btf_member *member;
3137 int err;
3138 u16 i;
3139
3140 /* Before continue resolving the next_member,
3141 * ensure the last member is indeed resolved to a
3142 * type with size info.
3143 */
3144 if (v->next_member) {
3145 const struct btf_type *last_member_type;
3146 const struct btf_member *last_member;
3147 u32 last_member_type_id;
3148
3149 last_member = btf_type_member(v->t) + v->next_member - 1;
3150 last_member_type_id = last_member->type;
3151 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3152 last_member_type_id)))
3153 return -EINVAL;
3154
3155 last_member_type = btf_type_by_id(env->btf,
3156 last_member_type_id);
3157 if (btf_type_kflag(v->t))
3158 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3159 last_member,
3160 last_member_type);
3161 else
3162 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3163 last_member,
3164 last_member_type);
3165 if (err)
3166 return err;
3167 }
3168
3169 for_each_member_from(i, v->next_member, v->t, member) {
3170 u32 member_type_id = member->type;
3171 const struct btf_type *member_type = btf_type_by_id(env->btf,
3172 member_type_id);
3173
3174 if (btf_type_nosize_or_null(member_type) ||
3175 btf_type_is_resolve_source_only(member_type)) {
3176 btf_verifier_log_member(env, v->t, member,
3177 "Invalid member");
3178 return -EINVAL;
3179 }
3180
3181 if (!env_type_is_resolve_sink(env, member_type) &&
3182 !env_type_is_resolved(env, member_type_id)) {
3183 env_stack_set_next_member(env, i + 1);
3184 return env_stack_push(env, member_type, member_type_id);
3185 }
3186
3187 if (btf_type_kflag(v->t))
3188 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3189 member,
3190 member_type);
3191 else
3192 err = btf_type_ops(member_type)->check_member(env, v->t,
3193 member,
3194 member_type);
3195 if (err)
3196 return err;
3197 }
3198
3199 env_stack_pop_resolved(env, 0, 0);
3200
3201 return 0;
3202}
3203
3204static void btf_struct_log(struct btf_verifier_env *env,
3205 const struct btf_type *t)
3206{
3207 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3208}
3209
3210enum btf_field_info_type {
3211 BTF_FIELD_SPIN_LOCK,
3212 BTF_FIELD_TIMER,
3213 BTF_FIELD_KPTR,
3214};
3215
3216enum {
3217 BTF_FIELD_IGNORE = 0,
3218 BTF_FIELD_FOUND = 1,
3219};
3220
3221struct btf_field_info {
3222 enum btf_field_type type;
3223 u32 off;
3224 union {
3225 struct {
3226 u32 type_id;
3227 } kptr;
3228 struct {
3229 const char *node_name;
3230 u32 value_btf_id;
3231 } list_head;
3232 };
3233};
3234
3235static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3236 u32 off, int sz, enum btf_field_type field_type,
3237 struct btf_field_info *info)
3238{
3239 if (!__btf_type_is_struct(t))
3240 return BTF_FIELD_IGNORE;
3241 if (t->size != sz)
3242 return BTF_FIELD_IGNORE;
3243 info->type = field_type;
3244 info->off = off;
3245 return BTF_FIELD_FOUND;
3246}
3247
3248static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3249 u32 off, int sz, struct btf_field_info *info)
3250{
3251 enum btf_field_type type;
3252 u32 res_id;
3253
3254 /* Permit modifiers on the pointer itself */
3255 if (btf_type_is_volatile(t))
3256 t = btf_type_by_id(btf, t->type);
3257 /* For PTR, sz is always == 8 */
3258 if (!btf_type_is_ptr(t))
3259 return BTF_FIELD_IGNORE;
3260 t = btf_type_by_id(btf, t->type);
3261
3262 if (!btf_type_is_type_tag(t))
3263 return BTF_FIELD_IGNORE;
3264 /* Reject extra tags */
3265 if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3266 return -EINVAL;
3267 if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3268 type = BPF_KPTR_UNREF;
3269 else if (!strcmp("kptr_ref", __btf_name_by_offset(btf, t->name_off)))
3270 type = BPF_KPTR_REF;
3271 else
3272 return -EINVAL;
3273
3274 /* Get the base type */
3275 t = btf_type_skip_modifiers(btf, t->type, &res_id);
3276 /* Only pointer to struct is allowed */
3277 if (!__btf_type_is_struct(t))
3278 return -EINVAL;
3279
3280 info->type = type;
3281 info->off = off;
3282 info->kptr.type_id = res_id;
3283 return BTF_FIELD_FOUND;
3284}
3285
3286static const char *btf_find_decl_tag_value(const struct btf *btf,
3287 const struct btf_type *pt,
3288 int comp_idx, const char *tag_key)
3289{
3290 int i;
3291
3292 for (i = 1; i < btf_nr_types(btf); i++) {
3293 const struct btf_type *t = btf_type_by_id(btf, i);
3294 int len = strlen(tag_key);
3295
3296 if (!btf_type_is_decl_tag(t))
3297 continue;
3298 if (pt != btf_type_by_id(btf, t->type) ||
3299 btf_type_decl_tag(t)->component_idx != comp_idx)
3300 continue;
3301 if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
3302 continue;
3303 return __btf_name_by_offset(btf, t->name_off) + len;
3304 }
3305 return NULL;
3306}
3307
3308static int btf_find_list_head(const struct btf *btf, const struct btf_type *pt,
3309 const struct btf_type *t, int comp_idx,
3310 u32 off, int sz, struct btf_field_info *info)
3311{
3312 const char *value_type;
3313 const char *list_node;
3314 s32 id;
3315
3316 if (!__btf_type_is_struct(t))
3317 return BTF_FIELD_IGNORE;
3318 if (t->size != sz)
3319 return BTF_FIELD_IGNORE;
3320 value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
3321 if (!value_type)
3322 return -EINVAL;
3323 list_node = strstr(value_type, ":");
3324 if (!list_node)
3325 return -EINVAL;
3326 value_type = kstrndup(value_type, list_node - value_type, GFP_KERNEL | __GFP_NOWARN);
3327 if (!value_type)
3328 return -ENOMEM;
3329 id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
3330 kfree(value_type);
3331 if (id < 0)
3332 return id;
3333 list_node++;
3334 if (str_is_empty(list_node))
3335 return -EINVAL;
3336 info->type = BPF_LIST_HEAD;
3337 info->off = off;
3338 info->list_head.value_btf_id = id;
3339 info->list_head.node_name = list_node;
3340 return BTF_FIELD_FOUND;
3341}
3342
3343static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask,
3344 int *align, int *sz)
3345{
3346 int type = 0;
3347
3348 if (field_mask & BPF_SPIN_LOCK) {
3349 if (!strcmp(name, "bpf_spin_lock")) {
3350 if (*seen_mask & BPF_SPIN_LOCK)
3351 return -E2BIG;
3352 *seen_mask |= BPF_SPIN_LOCK;
3353 type = BPF_SPIN_LOCK;
3354 goto end;
3355 }
3356 }
3357 if (field_mask & BPF_TIMER) {
3358 if (!strcmp(name, "bpf_timer")) {
3359 if (*seen_mask & BPF_TIMER)
3360 return -E2BIG;
3361 *seen_mask |= BPF_TIMER;
3362 type = BPF_TIMER;
3363 goto end;
3364 }
3365 }
3366 if (field_mask & BPF_LIST_HEAD) {
3367 if (!strcmp(name, "bpf_list_head")) {
3368 type = BPF_LIST_HEAD;
3369 goto end;
3370 }
3371 }
3372 if (field_mask & BPF_LIST_NODE) {
3373 if (!strcmp(name, "bpf_list_node")) {
3374 type = BPF_LIST_NODE;
3375 goto end;
3376 }
3377 }
3378 /* Only return BPF_KPTR when all other types with matchable names fail */
3379 if (field_mask & BPF_KPTR) {
3380 type = BPF_KPTR_REF;
3381 goto end;
3382 }
3383 return 0;
3384end:
3385 *sz = btf_field_type_size(type);
3386 *align = btf_field_type_align(type);
3387 return type;
3388}
3389
3390static int btf_find_struct_field(const struct btf *btf,
3391 const struct btf_type *t, u32 field_mask,
3392 struct btf_field_info *info, int info_cnt)
3393{
3394 int ret, idx = 0, align, sz, field_type;
3395 const struct btf_member *member;
3396 struct btf_field_info tmp;
3397 u32 i, off, seen_mask = 0;
3398
3399 for_each_member(i, t, member) {
3400 const struct btf_type *member_type = btf_type_by_id(btf,
3401 member->type);
3402
3403 field_type = btf_get_field_type(__btf_name_by_offset(btf, member_type->name_off),
3404 field_mask, &seen_mask, &align, &sz);
3405 if (field_type == 0)
3406 continue;
3407 if (field_type < 0)
3408 return field_type;
3409
3410 off = __btf_member_bit_offset(t, member);
3411 if (off % 8)
3412 /* valid C code cannot generate such BTF */
3413 return -EINVAL;
3414 off /= 8;
3415 if (off % align)
3416 continue;
3417
3418 switch (field_type) {
3419 case BPF_SPIN_LOCK:
3420 case BPF_TIMER:
3421 case BPF_LIST_NODE:
3422 ret = btf_find_struct(btf, member_type, off, sz, field_type,
3423 idx < info_cnt ? &info[idx] : &tmp);
3424 if (ret < 0)
3425 return ret;
3426 break;
3427 case BPF_KPTR_UNREF:
3428 case BPF_KPTR_REF:
3429 ret = btf_find_kptr(btf, member_type, off, sz,
3430 idx < info_cnt ? &info[idx] : &tmp);
3431 if (ret < 0)
3432 return ret;
3433 break;
3434 case BPF_LIST_HEAD:
3435 ret = btf_find_list_head(btf, t, member_type, i, off, sz,
3436 idx < info_cnt ? &info[idx] : &tmp);
3437 if (ret < 0)
3438 return ret;
3439 break;
3440 default:
3441 return -EFAULT;
3442 }
3443
3444 if (ret == BTF_FIELD_IGNORE)
3445 continue;
3446 if (idx >= info_cnt)
3447 return -E2BIG;
3448 ++idx;
3449 }
3450 return idx;
3451}
3452
3453static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3454 u32 field_mask, struct btf_field_info *info,
3455 int info_cnt)
3456{
3457 int ret, idx = 0, align, sz, field_type;
3458 const struct btf_var_secinfo *vsi;
3459 struct btf_field_info tmp;
3460 u32 i, off, seen_mask = 0;
3461
3462 for_each_vsi(i, t, vsi) {
3463 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3464 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3465
3466 field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off),
3467 field_mask, &seen_mask, &align, &sz);
3468 if (field_type == 0)
3469 continue;
3470 if (field_type < 0)
3471 return field_type;
3472
3473 off = vsi->offset;
3474 if (vsi->size != sz)
3475 continue;
3476 if (off % align)
3477 continue;
3478
3479 switch (field_type) {
3480 case BPF_SPIN_LOCK:
3481 case BPF_TIMER:
3482 case BPF_LIST_NODE:
3483 ret = btf_find_struct(btf, var_type, off, sz, field_type,
3484 idx < info_cnt ? &info[idx] : &tmp);
3485 if (ret < 0)
3486 return ret;
3487 break;
3488 case BPF_KPTR_UNREF:
3489 case BPF_KPTR_REF:
3490 ret = btf_find_kptr(btf, var_type, off, sz,
3491 idx < info_cnt ? &info[idx] : &tmp);
3492 if (ret < 0)
3493 return ret;
3494 break;
3495 case BPF_LIST_HEAD:
3496 ret = btf_find_list_head(btf, var, var_type, -1, off, sz,
3497 idx < info_cnt ? &info[idx] : &tmp);
3498 if (ret < 0)
3499 return ret;
3500 break;
3501 default:
3502 return -EFAULT;
3503 }
3504
3505 if (ret == BTF_FIELD_IGNORE)
3506 continue;
3507 if (idx >= info_cnt)
3508 return -E2BIG;
3509 ++idx;
3510 }
3511 return idx;
3512}
3513
3514static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3515 u32 field_mask, struct btf_field_info *info,
3516 int info_cnt)
3517{
3518 if (__btf_type_is_struct(t))
3519 return btf_find_struct_field(btf, t, field_mask, info, info_cnt);
3520 else if (btf_type_is_datasec(t))
3521 return btf_find_datasec_var(btf, t, field_mask, info, info_cnt);
3522 return -EINVAL;
3523}
3524
3525static int btf_parse_kptr(const struct btf *btf, struct btf_field *field,
3526 struct btf_field_info *info)
3527{
3528 struct module *mod = NULL;
3529 const struct btf_type *t;
3530 struct btf *kernel_btf;
3531 int ret;
3532 s32 id;
3533
3534 /* Find type in map BTF, and use it to look up the matching type
3535 * in vmlinux or module BTFs, by name and kind.
3536 */
3537 t = btf_type_by_id(btf, info->kptr.type_id);
3538 id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3539 &kernel_btf);
3540 if (id < 0)
3541 return id;
3542
3543 /* Find and stash the function pointer for the destruction function that
3544 * needs to be eventually invoked from the map free path.
3545 */
3546 if (info->type == BPF_KPTR_REF) {
3547 const struct btf_type *dtor_func;
3548 const char *dtor_func_name;
3549 unsigned long addr;
3550 s32 dtor_btf_id;
3551
3552 /* This call also serves as a whitelist of allowed objects that
3553 * can be used as a referenced pointer and be stored in a map at
3554 * the same time.
3555 */
3556 dtor_btf_id = btf_find_dtor_kfunc(kernel_btf, id);
3557 if (dtor_btf_id < 0) {
3558 ret = dtor_btf_id;
3559 goto end_btf;
3560 }
3561
3562 dtor_func = btf_type_by_id(kernel_btf, dtor_btf_id);
3563 if (!dtor_func) {
3564 ret = -ENOENT;
3565 goto end_btf;
3566 }
3567
3568 if (btf_is_module(kernel_btf)) {
3569 mod = btf_try_get_module(kernel_btf);
3570 if (!mod) {
3571 ret = -ENXIO;
3572 goto end_btf;
3573 }
3574 }
3575
3576 /* We already verified dtor_func to be btf_type_is_func
3577 * in register_btf_id_dtor_kfuncs.
3578 */
3579 dtor_func_name = __btf_name_by_offset(kernel_btf, dtor_func->name_off);
3580 addr = kallsyms_lookup_name(dtor_func_name);
3581 if (!addr) {
3582 ret = -EINVAL;
3583 goto end_mod;
3584 }
3585 field->kptr.dtor = (void *)addr;
3586 }
3587
3588 field->kptr.btf_id = id;
3589 field->kptr.btf = kernel_btf;
3590 field->kptr.module = mod;
3591 return 0;
3592end_mod:
3593 module_put(mod);
3594end_btf:
3595 btf_put(kernel_btf);
3596 return ret;
3597}
3598
3599static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
3600 struct btf_field_info *info)
3601{
3602 const struct btf_type *t, *n = NULL;
3603 const struct btf_member *member;
3604 u32 offset;
3605 int i;
3606
3607 t = btf_type_by_id(btf, info->list_head.value_btf_id);
3608 /* We've already checked that value_btf_id is a struct type. We
3609 * just need to figure out the offset of the list_node, and
3610 * verify its type.
3611 */
3612 for_each_member(i, t, member) {
3613 if (strcmp(info->list_head.node_name, __btf_name_by_offset(btf, member->name_off)))
3614 continue;
3615 /* Invalid BTF, two members with same name */
3616 if (n)
3617 return -EINVAL;
3618 n = btf_type_by_id(btf, member->type);
3619 if (!__btf_type_is_struct(n))
3620 return -EINVAL;
3621 if (strcmp("bpf_list_node", __btf_name_by_offset(btf, n->name_off)))
3622 return -EINVAL;
3623 offset = __btf_member_bit_offset(n, member);
3624 if (offset % 8)
3625 return -EINVAL;
3626 offset /= 8;
3627 if (offset % __alignof__(struct bpf_list_node))
3628 return -EINVAL;
3629
3630 field->list_head.btf = (struct btf *)btf;
3631 field->list_head.value_btf_id = info->list_head.value_btf_id;
3632 field->list_head.node_offset = offset;
3633 }
3634 if (!n)
3635 return -ENOENT;
3636 return 0;
3637}
3638
3639struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
3640 u32 field_mask, u32 value_size)
3641{
3642 struct btf_field_info info_arr[BTF_FIELDS_MAX];
3643 struct btf_record *rec;
3644 u32 next_off = 0;
3645 int ret, i, cnt;
3646
3647 ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
3648 if (ret < 0)
3649 return ERR_PTR(ret);
3650 if (!ret)
3651 return NULL;
3652
3653 cnt = ret;
3654 /* This needs to be kzalloc to zero out padding and unused fields, see
3655 * comment in btf_record_equal.
3656 */
3657 rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);
3658 if (!rec)
3659 return ERR_PTR(-ENOMEM);
3660
3661 rec->spin_lock_off = -EINVAL;
3662 rec->timer_off = -EINVAL;
3663 for (i = 0; i < cnt; i++) {
3664 if (info_arr[i].off + btf_field_type_size(info_arr[i].type) > value_size) {
3665 WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
3666 ret = -EFAULT;
3667 goto end;
3668 }
3669 if (info_arr[i].off < next_off) {
3670 ret = -EEXIST;
3671 goto end;
3672 }
3673 next_off = info_arr[i].off + btf_field_type_size(info_arr[i].type);
3674
3675 rec->field_mask |= info_arr[i].type;
3676 rec->fields[i].offset = info_arr[i].off;
3677 rec->fields[i].type = info_arr[i].type;
3678
3679 switch (info_arr[i].type) {
3680 case BPF_SPIN_LOCK:
3681 WARN_ON_ONCE(rec->spin_lock_off >= 0);
3682 /* Cache offset for faster lookup at runtime */
3683 rec->spin_lock_off = rec->fields[i].offset;
3684 break;
3685 case BPF_TIMER:
3686 WARN_ON_ONCE(rec->timer_off >= 0);
3687 /* Cache offset for faster lookup at runtime */
3688 rec->timer_off = rec->fields[i].offset;
3689 break;
3690 case BPF_KPTR_UNREF:
3691 case BPF_KPTR_REF:
3692 ret = btf_parse_kptr(btf, &rec->fields[i], &info_arr[i]);
3693 if (ret < 0)
3694 goto end;
3695 break;
3696 case BPF_LIST_HEAD:
3697 ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
3698 if (ret < 0)
3699 goto end;
3700 break;
3701 case BPF_LIST_NODE:
3702 break;
3703 default:
3704 ret = -EFAULT;
3705 goto end;
3706 }
3707 rec->cnt++;
3708 }
3709
3710 /* bpf_list_head requires bpf_spin_lock */
3711 if (btf_record_has_field(rec, BPF_LIST_HEAD) && rec->spin_lock_off < 0) {
3712 ret = -EINVAL;
3713 goto end;
3714 }
3715
3716 return rec;
3717end:
3718 btf_record_free(rec);
3719 return ERR_PTR(ret);
3720}
3721
3722int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
3723{
3724 int i;
3725
3726 /* There are two owning types, kptr_ref and bpf_list_head. The former
3727 * only supports storing kernel types, which can never store references
3728 * to program allocated local types, atleast not yet. Hence we only need
3729 * to ensure that bpf_list_head ownership does not form cycles.
3730 */
3731 if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & BPF_LIST_HEAD))
3732 return 0;
3733 for (i = 0; i < rec->cnt; i++) {
3734 struct btf_struct_meta *meta;
3735 u32 btf_id;
3736
3737 if (!(rec->fields[i].type & BPF_LIST_HEAD))
3738 continue;
3739 btf_id = rec->fields[i].list_head.value_btf_id;
3740 meta = btf_find_struct_meta(btf, btf_id);
3741 if (!meta)
3742 return -EFAULT;
3743 rec->fields[i].list_head.value_rec = meta->record;
3744
3745 if (!(rec->field_mask & BPF_LIST_NODE))
3746 continue;
3747
3748 /* We need to ensure ownership acyclicity among all types. The
3749 * proper way to do it would be to topologically sort all BTF
3750 * IDs based on the ownership edges, since there can be multiple
3751 * bpf_list_head in a type. Instead, we use the following
3752 * reasoning:
3753 *
3754 * - A type can only be owned by another type in user BTF if it
3755 * has a bpf_list_node.
3756 * - A type can only _own_ another type in user BTF if it has a
3757 * bpf_list_head.
3758 *
3759 * We ensure that if a type has both bpf_list_head and
3760 * bpf_list_node, its element types cannot be owning types.
3761 *
3762 * To ensure acyclicity:
3763 *
3764 * When A only has bpf_list_head, ownership chain can be:
3765 * A -> B -> C
3766 * Where:
3767 * - B has both bpf_list_head and bpf_list_node.
3768 * - C only has bpf_list_node.
3769 *
3770 * When A has both bpf_list_head and bpf_list_node, some other
3771 * type already owns it in the BTF domain, hence it can not own
3772 * another owning type through any of the bpf_list_head edges.
3773 * A -> B
3774 * Where:
3775 * - B only has bpf_list_node.
3776 */
3777 if (meta->record->field_mask & BPF_LIST_HEAD)
3778 return -ELOOP;
3779 }
3780 return 0;
3781}
3782
3783static int btf_field_offs_cmp(const void *_a, const void *_b, const void *priv)
3784{
3785 const u32 a = *(const u32 *)_a;
3786 const u32 b = *(const u32 *)_b;
3787
3788 if (a < b)
3789 return -1;
3790 else if (a > b)
3791 return 1;
3792 return 0;
3793}
3794
3795static void btf_field_offs_swap(void *_a, void *_b, int size, const void *priv)
3796{
3797 struct btf_field_offs *foffs = (void *)priv;
3798 u32 *off_base = foffs->field_off;
3799 u32 *a = _a, *b = _b;
3800 u8 *sz_a, *sz_b;
3801
3802 sz_a = foffs->field_sz + (a - off_base);
3803 sz_b = foffs->field_sz + (b - off_base);
3804
3805 swap(*a, *b);
3806 swap(*sz_a, *sz_b);
3807}
3808
3809struct btf_field_offs *btf_parse_field_offs(struct btf_record *rec)
3810{
3811 struct btf_field_offs *foffs;
3812 u32 i, *off;
3813 u8 *sz;
3814
3815 BUILD_BUG_ON(ARRAY_SIZE(foffs->field_off) != ARRAY_SIZE(foffs->field_sz));
3816 if (IS_ERR_OR_NULL(rec))
3817 return NULL;
3818
3819 foffs = kzalloc(sizeof(*foffs), GFP_KERNEL | __GFP_NOWARN);
3820 if (!foffs)
3821 return ERR_PTR(-ENOMEM);
3822
3823 off = foffs->field_off;
3824 sz = foffs->field_sz;
3825 for (i = 0; i < rec->cnt; i++) {
3826 off[i] = rec->fields[i].offset;
3827 sz[i] = btf_field_type_size(rec->fields[i].type);
3828 }
3829 foffs->cnt = rec->cnt;
3830
3831 if (foffs->cnt == 1)
3832 return foffs;
3833 sort_r(foffs->field_off, foffs->cnt, sizeof(foffs->field_off[0]),
3834 btf_field_offs_cmp, btf_field_offs_swap, foffs);
3835 return foffs;
3836}
3837
3838static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3839 u32 type_id, void *data, u8 bits_offset,
3840 struct btf_show *show)
3841{
3842 const struct btf_member *member;
3843 void *safe_data;
3844 u32 i;
3845
3846 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3847 if (!safe_data)
3848 return;
3849
3850 for_each_member(i, t, member) {
3851 const struct btf_type *member_type = btf_type_by_id(btf,
3852 member->type);
3853 const struct btf_kind_operations *ops;
3854 u32 member_offset, bitfield_size;
3855 u32 bytes_offset;
3856 u8 bits8_offset;
3857
3858 btf_show_start_member(show, member);
3859
3860 member_offset = __btf_member_bit_offset(t, member);
3861 bitfield_size = __btf_member_bitfield_size(t, member);
3862 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3863 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3864 if (bitfield_size) {
3865 safe_data = btf_show_start_type(show, member_type,
3866 member->type,
3867 data + bytes_offset);
3868 if (safe_data)
3869 btf_bitfield_show(safe_data,
3870 bits8_offset,
3871 bitfield_size, show);
3872 btf_show_end_type(show);
3873 } else {
3874 ops = btf_type_ops(member_type);
3875 ops->show(btf, member_type, member->type,
3876 data + bytes_offset, bits8_offset, show);
3877 }
3878
3879 btf_show_end_member(show);
3880 }
3881
3882 btf_show_end_struct_type(show);
3883}
3884
3885static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3886 u32 type_id, void *data, u8 bits_offset,
3887 struct btf_show *show)
3888{
3889 const struct btf_member *m = show->state.member;
3890
3891 /*
3892 * First check if any members would be shown (are non-zero).
3893 * See comments above "struct btf_show" definition for more
3894 * details on how this works at a high-level.
3895 */
3896 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3897 if (!show->state.depth_check) {
3898 show->state.depth_check = show->state.depth + 1;
3899 show->state.depth_to_show = 0;
3900 }
3901 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3902 /* Restore saved member data here */
3903 show->state.member = m;
3904 if (show->state.depth_check != show->state.depth + 1)
3905 return;
3906 show->state.depth_check = 0;
3907
3908 if (show->state.depth_to_show <= show->state.depth)
3909 return;
3910 /*
3911 * Reaching here indicates we have recursed and found
3912 * non-zero child values.
3913 */
3914 }
3915
3916 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3917}
3918
3919static struct btf_kind_operations struct_ops = {
3920 .check_meta = btf_struct_check_meta,
3921 .resolve = btf_struct_resolve,
3922 .check_member = btf_struct_check_member,
3923 .check_kflag_member = btf_generic_check_kflag_member,
3924 .log_details = btf_struct_log,
3925 .show = btf_struct_show,
3926};
3927
3928static int btf_enum_check_member(struct btf_verifier_env *env,
3929 const struct btf_type *struct_type,
3930 const struct btf_member *member,
3931 const struct btf_type *member_type)
3932{
3933 u32 struct_bits_off = member->offset;
3934 u32 struct_size, bytes_offset;
3935
3936 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3937 btf_verifier_log_member(env, struct_type, member,
3938 "Member is not byte aligned");
3939 return -EINVAL;
3940 }
3941
3942 struct_size = struct_type->size;
3943 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3944 if (struct_size - bytes_offset < member_type->size) {
3945 btf_verifier_log_member(env, struct_type, member,
3946 "Member exceeds struct_size");
3947 return -EINVAL;
3948 }
3949
3950 return 0;
3951}
3952
3953static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
3954 const struct btf_type *struct_type,
3955 const struct btf_member *member,
3956 const struct btf_type *member_type)
3957{
3958 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
3959 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
3960
3961 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
3962 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
3963 if (!nr_bits) {
3964 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3965 btf_verifier_log_member(env, struct_type, member,
3966 "Member is not byte aligned");
3967 return -EINVAL;
3968 }
3969
3970 nr_bits = int_bitsize;
3971 } else if (nr_bits > int_bitsize) {
3972 btf_verifier_log_member(env, struct_type, member,
3973 "Invalid member bitfield_size");
3974 return -EINVAL;
3975 }
3976
3977 struct_size = struct_type->size;
3978 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
3979 if (struct_size < bytes_end) {
3980 btf_verifier_log_member(env, struct_type, member,
3981 "Member exceeds struct_size");
3982 return -EINVAL;
3983 }
3984
3985 return 0;
3986}
3987
3988static s32 btf_enum_check_meta(struct btf_verifier_env *env,
3989 const struct btf_type *t,
3990 u32 meta_left)
3991{
3992 const struct btf_enum *enums = btf_type_enum(t);
3993 struct btf *btf = env->btf;
3994 const char *fmt_str;
3995 u16 i, nr_enums;
3996 u32 meta_needed;
3997
3998 nr_enums = btf_type_vlen(t);
3999 meta_needed = nr_enums * sizeof(*enums);
4000
4001 if (meta_left < meta_needed) {
4002 btf_verifier_log_basic(env, t,
4003 "meta_left:%u meta_needed:%u",
4004 meta_left, meta_needed);
4005 return -EINVAL;
4006 }
4007
4008 if (t->size > 8 || !is_power_of_2(t->size)) {
4009 btf_verifier_log_type(env, t, "Unexpected size");
4010 return -EINVAL;
4011 }
4012
4013 /* enum type either no name or a valid one */
4014 if (t->name_off &&
4015 !btf_name_valid_identifier(env->btf, t->name_off)) {
4016 btf_verifier_log_type(env, t, "Invalid name");
4017 return -EINVAL;
4018 }
4019
4020 btf_verifier_log_type(env, t, NULL);
4021
4022 for (i = 0; i < nr_enums; i++) {
4023 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4024 btf_verifier_log(env, "\tInvalid name_offset:%u",
4025 enums[i].name_off);
4026 return -EINVAL;
4027 }
4028
4029 /* enum member must have a valid name */
4030 if (!enums[i].name_off ||
4031 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4032 btf_verifier_log_type(env, t, "Invalid name");
4033 return -EINVAL;
4034 }
4035
4036 if (env->log.level == BPF_LOG_KERNEL)
4037 continue;
4038 fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
4039 btf_verifier_log(env, fmt_str,
4040 __btf_name_by_offset(btf, enums[i].name_off),
4041 enums[i].val);
4042 }
4043
4044 return meta_needed;
4045}
4046
4047static void btf_enum_log(struct btf_verifier_env *env,
4048 const struct btf_type *t)
4049{
4050 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4051}
4052
4053static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
4054 u32 type_id, void *data, u8 bits_offset,
4055 struct btf_show *show)
4056{
4057 const struct btf_enum *enums = btf_type_enum(t);
4058 u32 i, nr_enums = btf_type_vlen(t);
4059 void *safe_data;
4060 int v;
4061
4062 safe_data = btf_show_start_type(show, t, type_id, data);
4063 if (!safe_data)
4064 return;
4065
4066 v = *(int *)safe_data;
4067
4068 for (i = 0; i < nr_enums; i++) {
4069 if (v != enums[i].val)
4070 continue;
4071
4072 btf_show_type_value(show, "%s",
4073 __btf_name_by_offset(btf,
4074 enums[i].name_off));
4075
4076 btf_show_end_type(show);
4077 return;
4078 }
4079
4080 if (btf_type_kflag(t))
4081 btf_show_type_value(show, "%d", v);
4082 else
4083 btf_show_type_value(show, "%u", v);
4084 btf_show_end_type(show);
4085}
4086
4087static struct btf_kind_operations enum_ops = {
4088 .check_meta = btf_enum_check_meta,
4089 .resolve = btf_df_resolve,
4090 .check_member = btf_enum_check_member,
4091 .check_kflag_member = btf_enum_check_kflag_member,
4092 .log_details = btf_enum_log,
4093 .show = btf_enum_show,
4094};
4095
4096static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
4097 const struct btf_type *t,
4098 u32 meta_left)
4099{
4100 const struct btf_enum64 *enums = btf_type_enum64(t);
4101 struct btf *btf = env->btf;
4102 const char *fmt_str;
4103 u16 i, nr_enums;
4104 u32 meta_needed;
4105
4106 nr_enums = btf_type_vlen(t);
4107 meta_needed = nr_enums * sizeof(*enums);
4108
4109 if (meta_left < meta_needed) {
4110 btf_verifier_log_basic(env, t,
4111 "meta_left:%u meta_needed:%u",
4112 meta_left, meta_needed);
4113 return -EINVAL;
4114 }
4115
4116 if (t->size > 8 || !is_power_of_2(t->size)) {
4117 btf_verifier_log_type(env, t, "Unexpected size");
4118 return -EINVAL;
4119 }
4120
4121 /* enum type either no name or a valid one */
4122 if (t->name_off &&
4123 !btf_name_valid_identifier(env->btf, t->name_off)) {
4124 btf_verifier_log_type(env, t, "Invalid name");
4125 return -EINVAL;
4126 }
4127
4128 btf_verifier_log_type(env, t, NULL);
4129
4130 for (i = 0; i < nr_enums; i++) {
4131 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4132 btf_verifier_log(env, "\tInvalid name_offset:%u",
4133 enums[i].name_off);
4134 return -EINVAL;
4135 }
4136
4137 /* enum member must have a valid name */
4138 if (!enums[i].name_off ||
4139 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4140 btf_verifier_log_type(env, t, "Invalid name");
4141 return -EINVAL;
4142 }
4143
4144 if (env->log.level == BPF_LOG_KERNEL)
4145 continue;
4146
4147 fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
4148 btf_verifier_log(env, fmt_str,
4149 __btf_name_by_offset(btf, enums[i].name_off),
4150 btf_enum64_value(enums + i));
4151 }
4152
4153 return meta_needed;
4154}
4155
4156static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
4157 u32 type_id, void *data, u8 bits_offset,
4158 struct btf_show *show)
4159{
4160 const struct btf_enum64 *enums = btf_type_enum64(t);
4161 u32 i, nr_enums = btf_type_vlen(t);
4162 void *safe_data;
4163 s64 v;
4164
4165 safe_data = btf_show_start_type(show, t, type_id, data);
4166 if (!safe_data)
4167 return;
4168
4169 v = *(u64 *)safe_data;
4170
4171 for (i = 0; i < nr_enums; i++) {
4172 if (v != btf_enum64_value(enums + i))
4173 continue;
4174
4175 btf_show_type_value(show, "%s",
4176 __btf_name_by_offset(btf,
4177 enums[i].name_off));
4178
4179 btf_show_end_type(show);
4180 return;
4181 }
4182
4183 if (btf_type_kflag(t))
4184 btf_show_type_value(show, "%lld", v);
4185 else
4186 btf_show_type_value(show, "%llu", v);
4187 btf_show_end_type(show);
4188}
4189
4190static struct btf_kind_operations enum64_ops = {
4191 .check_meta = btf_enum64_check_meta,
4192 .resolve = btf_df_resolve,
4193 .check_member = btf_enum_check_member,
4194 .check_kflag_member = btf_enum_check_kflag_member,
4195 .log_details = btf_enum_log,
4196 .show = btf_enum64_show,
4197};
4198
4199static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
4200 const struct btf_type *t,
4201 u32 meta_left)
4202{
4203 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
4204
4205 if (meta_left < meta_needed) {
4206 btf_verifier_log_basic(env, t,
4207 "meta_left:%u meta_needed:%u",
4208 meta_left, meta_needed);
4209 return -EINVAL;
4210 }
4211
4212 if (t->name_off) {
4213 btf_verifier_log_type(env, t, "Invalid name");
4214 return -EINVAL;
4215 }
4216
4217 if (btf_type_kflag(t)) {
4218 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4219 return -EINVAL;
4220 }
4221
4222 btf_verifier_log_type(env, t, NULL);
4223
4224 return meta_needed;
4225}
4226
4227static void btf_func_proto_log(struct btf_verifier_env *env,
4228 const struct btf_type *t)
4229{
4230 const struct btf_param *args = (const struct btf_param *)(t + 1);
4231 u16 nr_args = btf_type_vlen(t), i;
4232
4233 btf_verifier_log(env, "return=%u args=(", t->type);
4234 if (!nr_args) {
4235 btf_verifier_log(env, "void");
4236 goto done;
4237 }
4238
4239 if (nr_args == 1 && !args[0].type) {
4240 /* Only one vararg */
4241 btf_verifier_log(env, "vararg");
4242 goto done;
4243 }
4244
4245 btf_verifier_log(env, "%u %s", args[0].type,
4246 __btf_name_by_offset(env->btf,
4247 args[0].name_off));
4248 for (i = 1; i < nr_args - 1; i++)
4249 btf_verifier_log(env, ", %u %s", args[i].type,
4250 __btf_name_by_offset(env->btf,
4251 args[i].name_off));
4252
4253 if (nr_args > 1) {
4254 const struct btf_param *last_arg = &args[nr_args - 1];
4255
4256 if (last_arg->type)
4257 btf_verifier_log(env, ", %u %s", last_arg->type,
4258 __btf_name_by_offset(env->btf,
4259 last_arg->name_off));
4260 else
4261 btf_verifier_log(env, ", vararg");
4262 }
4263
4264done:
4265 btf_verifier_log(env, ")");
4266}
4267
4268static struct btf_kind_operations func_proto_ops = {
4269 .check_meta = btf_func_proto_check_meta,
4270 .resolve = btf_df_resolve,
4271 /*
4272 * BTF_KIND_FUNC_PROTO cannot be directly referred by
4273 * a struct's member.
4274 *
4275 * It should be a function pointer instead.
4276 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
4277 *
4278 * Hence, there is no btf_func_check_member().
4279 */
4280 .check_member = btf_df_check_member,
4281 .check_kflag_member = btf_df_check_kflag_member,
4282 .log_details = btf_func_proto_log,
4283 .show = btf_df_show,
4284};
4285
4286static s32 btf_func_check_meta(struct btf_verifier_env *env,
4287 const struct btf_type *t,
4288 u32 meta_left)
4289{
4290 if (!t->name_off ||
4291 !btf_name_valid_identifier(env->btf, t->name_off)) {
4292 btf_verifier_log_type(env, t, "Invalid name");
4293 return -EINVAL;
4294 }
4295
4296 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
4297 btf_verifier_log_type(env, t, "Invalid func linkage");
4298 return -EINVAL;
4299 }
4300
4301 if (btf_type_kflag(t)) {
4302 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4303 return -EINVAL;
4304 }
4305
4306 btf_verifier_log_type(env, t, NULL);
4307
4308 return 0;
4309}
4310
4311static int btf_func_resolve(struct btf_verifier_env *env,
4312 const struct resolve_vertex *v)
4313{
4314 const struct btf_type *t = v->t;
4315 u32 next_type_id = t->type;
4316 int err;
4317
4318 err = btf_func_check(env, t);
4319 if (err)
4320 return err;
4321
4322 env_stack_pop_resolved(env, next_type_id, 0);
4323 return 0;
4324}
4325
4326static struct btf_kind_operations func_ops = {
4327 .check_meta = btf_func_check_meta,
4328 .resolve = btf_func_resolve,
4329 .check_member = btf_df_check_member,
4330 .check_kflag_member = btf_df_check_kflag_member,
4331 .log_details = btf_ref_type_log,
4332 .show = btf_df_show,
4333};
4334
4335static s32 btf_var_check_meta(struct btf_verifier_env *env,
4336 const struct btf_type *t,
4337 u32 meta_left)
4338{
4339 const struct btf_var *var;
4340 u32 meta_needed = sizeof(*var);
4341
4342 if (meta_left < meta_needed) {
4343 btf_verifier_log_basic(env, t,
4344 "meta_left:%u meta_needed:%u",
4345 meta_left, meta_needed);
4346 return -EINVAL;
4347 }
4348
4349 if (btf_type_vlen(t)) {
4350 btf_verifier_log_type(env, t, "vlen != 0");
4351 return -EINVAL;
4352 }
4353
4354 if (btf_type_kflag(t)) {
4355 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4356 return -EINVAL;
4357 }
4358
4359 if (!t->name_off ||
4360 !__btf_name_valid(env->btf, t->name_off, true)) {
4361 btf_verifier_log_type(env, t, "Invalid name");
4362 return -EINVAL;
4363 }
4364
4365 /* A var cannot be in type void */
4366 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4367 btf_verifier_log_type(env, t, "Invalid type_id");
4368 return -EINVAL;
4369 }
4370
4371 var = btf_type_var(t);
4372 if (var->linkage != BTF_VAR_STATIC &&
4373 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4374 btf_verifier_log_type(env, t, "Linkage not supported");
4375 return -EINVAL;
4376 }
4377
4378 btf_verifier_log_type(env, t, NULL);
4379
4380 return meta_needed;
4381}
4382
4383static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4384{
4385 const struct btf_var *var = btf_type_var(t);
4386
4387 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4388}
4389
4390static const struct btf_kind_operations var_ops = {
4391 .check_meta = btf_var_check_meta,
4392 .resolve = btf_var_resolve,
4393 .check_member = btf_df_check_member,
4394 .check_kflag_member = btf_df_check_kflag_member,
4395 .log_details = btf_var_log,
4396 .show = btf_var_show,
4397};
4398
4399static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4400 const struct btf_type *t,
4401 u32 meta_left)
4402{
4403 const struct btf_var_secinfo *vsi;
4404 u64 last_vsi_end_off = 0, sum = 0;
4405 u32 i, meta_needed;
4406
4407 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4408 if (meta_left < meta_needed) {
4409 btf_verifier_log_basic(env, t,
4410 "meta_left:%u meta_needed:%u",
4411 meta_left, meta_needed);
4412 return -EINVAL;
4413 }
4414
4415 if (!t->size) {
4416 btf_verifier_log_type(env, t, "size == 0");
4417 return -EINVAL;
4418 }
4419
4420 if (btf_type_kflag(t)) {
4421 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4422 return -EINVAL;
4423 }
4424
4425 if (!t->name_off ||
4426 !btf_name_valid_section(env->btf, t->name_off)) {
4427 btf_verifier_log_type(env, t, "Invalid name");
4428 return -EINVAL;
4429 }
4430
4431 btf_verifier_log_type(env, t, NULL);
4432
4433 for_each_vsi(i, t, vsi) {
4434 /* A var cannot be in type void */
4435 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4436 btf_verifier_log_vsi(env, t, vsi,
4437 "Invalid type_id");
4438 return -EINVAL;
4439 }
4440
4441 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4442 btf_verifier_log_vsi(env, t, vsi,
4443 "Invalid offset");
4444 return -EINVAL;
4445 }
4446
4447 if (!vsi->size || vsi->size > t->size) {
4448 btf_verifier_log_vsi(env, t, vsi,
4449 "Invalid size");
4450 return -EINVAL;
4451 }
4452
4453 last_vsi_end_off = vsi->offset + vsi->size;
4454 if (last_vsi_end_off > t->size) {
4455 btf_verifier_log_vsi(env, t, vsi,
4456 "Invalid offset+size");
4457 return -EINVAL;
4458 }
4459
4460 btf_verifier_log_vsi(env, t, vsi, NULL);
4461 sum += vsi->size;
4462 }
4463
4464 if (t->size < sum) {
4465 btf_verifier_log_type(env, t, "Invalid btf_info size");
4466 return -EINVAL;
4467 }
4468
4469 return meta_needed;
4470}
4471
4472static int btf_datasec_resolve(struct btf_verifier_env *env,
4473 const struct resolve_vertex *v)
4474{
4475 const struct btf_var_secinfo *vsi;
4476 struct btf *btf = env->btf;
4477 u16 i;
4478
4479 for_each_vsi_from(i, v->next_member, v->t, vsi) {
4480 u32 var_type_id = vsi->type, type_id, type_size = 0;
4481 const struct btf_type *var_type = btf_type_by_id(env->btf,
4482 var_type_id);
4483 if (!var_type || !btf_type_is_var(var_type)) {
4484 btf_verifier_log_vsi(env, v->t, vsi,
4485 "Not a VAR kind member");
4486 return -EINVAL;
4487 }
4488
4489 if (!env_type_is_resolve_sink(env, var_type) &&
4490 !env_type_is_resolved(env, var_type_id)) {
4491 env_stack_set_next_member(env, i + 1);
4492 return env_stack_push(env, var_type, var_type_id);
4493 }
4494
4495 type_id = var_type->type;
4496 if (!btf_type_id_size(btf, &type_id, &type_size)) {
4497 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4498 return -EINVAL;
4499 }
4500
4501 if (vsi->size < type_size) {
4502 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4503 return -EINVAL;
4504 }
4505 }
4506
4507 env_stack_pop_resolved(env, 0, 0);
4508 return 0;
4509}
4510
4511static void btf_datasec_log(struct btf_verifier_env *env,
4512 const struct btf_type *t)
4513{
4514 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4515}
4516
4517static void btf_datasec_show(const struct btf *btf,
4518 const struct btf_type *t, u32 type_id,
4519 void *data, u8 bits_offset,
4520 struct btf_show *show)
4521{
4522 const struct btf_var_secinfo *vsi;
4523 const struct btf_type *var;
4524 u32 i;
4525
4526 if (!btf_show_start_type(show, t, type_id, data))
4527 return;
4528
4529 btf_show_type_value(show, "section (\"%s\") = {",
4530 __btf_name_by_offset(btf, t->name_off));
4531 for_each_vsi(i, t, vsi) {
4532 var = btf_type_by_id(btf, vsi->type);
4533 if (i)
4534 btf_show(show, ",");
4535 btf_type_ops(var)->show(btf, var, vsi->type,
4536 data + vsi->offset, bits_offset, show);
4537 }
4538 btf_show_end_type(show);
4539}
4540
4541static const struct btf_kind_operations datasec_ops = {
4542 .check_meta = btf_datasec_check_meta,
4543 .resolve = btf_datasec_resolve,
4544 .check_member = btf_df_check_member,
4545 .check_kflag_member = btf_df_check_kflag_member,
4546 .log_details = btf_datasec_log,
4547 .show = btf_datasec_show,
4548};
4549
4550static s32 btf_float_check_meta(struct btf_verifier_env *env,
4551 const struct btf_type *t,
4552 u32 meta_left)
4553{
4554 if (btf_type_vlen(t)) {
4555 btf_verifier_log_type(env, t, "vlen != 0");
4556 return -EINVAL;
4557 }
4558
4559 if (btf_type_kflag(t)) {
4560 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4561 return -EINVAL;
4562 }
4563
4564 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4565 t->size != 16) {
4566 btf_verifier_log_type(env, t, "Invalid type_size");
4567 return -EINVAL;
4568 }
4569
4570 btf_verifier_log_type(env, t, NULL);
4571
4572 return 0;
4573}
4574
4575static int btf_float_check_member(struct btf_verifier_env *env,
4576 const struct btf_type *struct_type,
4577 const struct btf_member *member,
4578 const struct btf_type *member_type)
4579{
4580 u64 start_offset_bytes;
4581 u64 end_offset_bytes;
4582 u64 misalign_bits;
4583 u64 align_bytes;
4584 u64 align_bits;
4585
4586 /* Different architectures have different alignment requirements, so
4587 * here we check only for the reasonable minimum. This way we ensure
4588 * that types after CO-RE can pass the kernel BTF verifier.
4589 */
4590 align_bytes = min_t(u64, sizeof(void *), member_type->size);
4591 align_bits = align_bytes * BITS_PER_BYTE;
4592 div64_u64_rem(member->offset, align_bits, &misalign_bits);
4593 if (misalign_bits) {
4594 btf_verifier_log_member(env, struct_type, member,
4595 "Member is not properly aligned");
4596 return -EINVAL;
4597 }
4598
4599 start_offset_bytes = member->offset / BITS_PER_BYTE;
4600 end_offset_bytes = start_offset_bytes + member_type->size;
4601 if (end_offset_bytes > struct_type->size) {
4602 btf_verifier_log_member(env, struct_type, member,
4603 "Member exceeds struct_size");
4604 return -EINVAL;
4605 }
4606
4607 return 0;
4608}
4609
4610static void btf_float_log(struct btf_verifier_env *env,
4611 const struct btf_type *t)
4612{
4613 btf_verifier_log(env, "size=%u", t->size);
4614}
4615
4616static const struct btf_kind_operations float_ops = {
4617 .check_meta = btf_float_check_meta,
4618 .resolve = btf_df_resolve,
4619 .check_member = btf_float_check_member,
4620 .check_kflag_member = btf_generic_check_kflag_member,
4621 .log_details = btf_float_log,
4622 .show = btf_df_show,
4623};
4624
4625static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4626 const struct btf_type *t,
4627 u32 meta_left)
4628{
4629 const struct btf_decl_tag *tag;
4630 u32 meta_needed = sizeof(*tag);
4631 s32 component_idx;
4632 const char *value;
4633
4634 if (meta_left < meta_needed) {
4635 btf_verifier_log_basic(env, t,
4636 "meta_left:%u meta_needed:%u",
4637 meta_left, meta_needed);
4638 return -EINVAL;
4639 }
4640
4641 value = btf_name_by_offset(env->btf, t->name_off);
4642 if (!value || !value[0]) {
4643 btf_verifier_log_type(env, t, "Invalid value");
4644 return -EINVAL;
4645 }
4646
4647 if (btf_type_vlen(t)) {
4648 btf_verifier_log_type(env, t, "vlen != 0");
4649 return -EINVAL;
4650 }
4651
4652 if (btf_type_kflag(t)) {
4653 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4654 return -EINVAL;
4655 }
4656
4657 component_idx = btf_type_decl_tag(t)->component_idx;
4658 if (component_idx < -1) {
4659 btf_verifier_log_type(env, t, "Invalid component_idx");
4660 return -EINVAL;
4661 }
4662
4663 btf_verifier_log_type(env, t, NULL);
4664
4665 return meta_needed;
4666}
4667
4668static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4669 const struct resolve_vertex *v)
4670{
4671 const struct btf_type *next_type;
4672 const struct btf_type *t = v->t;
4673 u32 next_type_id = t->type;
4674 struct btf *btf = env->btf;
4675 s32 component_idx;
4676 u32 vlen;
4677
4678 next_type = btf_type_by_id(btf, next_type_id);
4679 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4680 btf_verifier_log_type(env, v->t, "Invalid type_id");
4681 return -EINVAL;
4682 }
4683
4684 if (!env_type_is_resolve_sink(env, next_type) &&
4685 !env_type_is_resolved(env, next_type_id))
4686 return env_stack_push(env, next_type, next_type_id);
4687
4688 component_idx = btf_type_decl_tag(t)->component_idx;
4689 if (component_idx != -1) {
4690 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4691 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4692 return -EINVAL;
4693 }
4694
4695 if (btf_type_is_struct(next_type)) {
4696 vlen = btf_type_vlen(next_type);
4697 } else {
4698 /* next_type should be a function */
4699 next_type = btf_type_by_id(btf, next_type->type);
4700 vlen = btf_type_vlen(next_type);
4701 }
4702
4703 if ((u32)component_idx >= vlen) {
4704 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4705 return -EINVAL;
4706 }
4707 }
4708
4709 env_stack_pop_resolved(env, next_type_id, 0);
4710
4711 return 0;
4712}
4713
4714static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
4715{
4716 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
4717 btf_type_decl_tag(t)->component_idx);
4718}
4719
4720static const struct btf_kind_operations decl_tag_ops = {
4721 .check_meta = btf_decl_tag_check_meta,
4722 .resolve = btf_decl_tag_resolve,
4723 .check_member = btf_df_check_member,
4724 .check_kflag_member = btf_df_check_kflag_member,
4725 .log_details = btf_decl_tag_log,
4726 .show = btf_df_show,
4727};
4728
4729static int btf_func_proto_check(struct btf_verifier_env *env,
4730 const struct btf_type *t)
4731{
4732 const struct btf_type *ret_type;
4733 const struct btf_param *args;
4734 const struct btf *btf;
4735 u16 nr_args, i;
4736 int err;
4737
4738 btf = env->btf;
4739 args = (const struct btf_param *)(t + 1);
4740 nr_args = btf_type_vlen(t);
4741
4742 /* Check func return type which could be "void" (t->type == 0) */
4743 if (t->type) {
4744 u32 ret_type_id = t->type;
4745
4746 ret_type = btf_type_by_id(btf, ret_type_id);
4747 if (!ret_type) {
4748 btf_verifier_log_type(env, t, "Invalid return type");
4749 return -EINVAL;
4750 }
4751
4752 if (btf_type_is_resolve_source_only(ret_type)) {
4753 btf_verifier_log_type(env, t, "Invalid return type");
4754 return -EINVAL;
4755 }
4756
4757 if (btf_type_needs_resolve(ret_type) &&
4758 !env_type_is_resolved(env, ret_type_id)) {
4759 err = btf_resolve(env, ret_type, ret_type_id);
4760 if (err)
4761 return err;
4762 }
4763
4764 /* Ensure the return type is a type that has a size */
4765 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
4766 btf_verifier_log_type(env, t, "Invalid return type");
4767 return -EINVAL;
4768 }
4769 }
4770
4771 if (!nr_args)
4772 return 0;
4773
4774 /* Last func arg type_id could be 0 if it is a vararg */
4775 if (!args[nr_args - 1].type) {
4776 if (args[nr_args - 1].name_off) {
4777 btf_verifier_log_type(env, t, "Invalid arg#%u",
4778 nr_args);
4779 return -EINVAL;
4780 }
4781 nr_args--;
4782 }
4783
4784 for (i = 0; i < nr_args; i++) {
4785 const struct btf_type *arg_type;
4786 u32 arg_type_id;
4787
4788 arg_type_id = args[i].type;
4789 arg_type = btf_type_by_id(btf, arg_type_id);
4790 if (!arg_type) {
4791 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4792 return -EINVAL;
4793 }
4794
4795 if (btf_type_is_resolve_source_only(arg_type)) {
4796 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4797 return -EINVAL;
4798 }
4799
4800 if (args[i].name_off &&
4801 (!btf_name_offset_valid(btf, args[i].name_off) ||
4802 !btf_name_valid_identifier(btf, args[i].name_off))) {
4803 btf_verifier_log_type(env, t,
4804 "Invalid arg#%u", i + 1);
4805 return -EINVAL;
4806 }
4807
4808 if (btf_type_needs_resolve(arg_type) &&
4809 !env_type_is_resolved(env, arg_type_id)) {
4810 err = btf_resolve(env, arg_type, arg_type_id);
4811 if (err)
4812 return err;
4813 }
4814
4815 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4816 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4817 return -EINVAL;
4818 }
4819 }
4820
4821 return 0;
4822}
4823
4824static int btf_func_check(struct btf_verifier_env *env,
4825 const struct btf_type *t)
4826{
4827 const struct btf_type *proto_type;
4828 const struct btf_param *args;
4829 const struct btf *btf;
4830 u16 nr_args, i;
4831
4832 btf = env->btf;
4833 proto_type = btf_type_by_id(btf, t->type);
4834
4835 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4836 btf_verifier_log_type(env, t, "Invalid type_id");
4837 return -EINVAL;
4838 }
4839
4840 args = (const struct btf_param *)(proto_type + 1);
4841 nr_args = btf_type_vlen(proto_type);
4842 for (i = 0; i < nr_args; i++) {
4843 if (!args[i].name_off && args[i].type) {
4844 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4845 return -EINVAL;
4846 }
4847 }
4848
4849 return 0;
4850}
4851
4852static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4853 [BTF_KIND_INT] = &int_ops,
4854 [BTF_KIND_PTR] = &ptr_ops,
4855 [BTF_KIND_ARRAY] = &array_ops,
4856 [BTF_KIND_STRUCT] = &struct_ops,
4857 [BTF_KIND_UNION] = &struct_ops,
4858 [BTF_KIND_ENUM] = &enum_ops,
4859 [BTF_KIND_FWD] = &fwd_ops,
4860 [BTF_KIND_TYPEDEF] = &modifier_ops,
4861 [BTF_KIND_VOLATILE] = &modifier_ops,
4862 [BTF_KIND_CONST] = &modifier_ops,
4863 [BTF_KIND_RESTRICT] = &modifier_ops,
4864 [BTF_KIND_FUNC] = &func_ops,
4865 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
4866 [BTF_KIND_VAR] = &var_ops,
4867 [BTF_KIND_DATASEC] = &datasec_ops,
4868 [BTF_KIND_FLOAT] = &float_ops,
4869 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
4870 [BTF_KIND_TYPE_TAG] = &modifier_ops,
4871 [BTF_KIND_ENUM64] = &enum64_ops,
4872};
4873
4874static s32 btf_check_meta(struct btf_verifier_env *env,
4875 const struct btf_type *t,
4876 u32 meta_left)
4877{
4878 u32 saved_meta_left = meta_left;
4879 s32 var_meta_size;
4880
4881 if (meta_left < sizeof(*t)) {
4882 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
4883 env->log_type_id, meta_left, sizeof(*t));
4884 return -EINVAL;
4885 }
4886 meta_left -= sizeof(*t);
4887
4888 if (t->info & ~BTF_INFO_MASK) {
4889 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
4890 env->log_type_id, t->info);
4891 return -EINVAL;
4892 }
4893
4894 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
4895 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
4896 btf_verifier_log(env, "[%u] Invalid kind:%u",
4897 env->log_type_id, BTF_INFO_KIND(t->info));
4898 return -EINVAL;
4899 }
4900
4901 if (!btf_name_offset_valid(env->btf, t->name_off)) {
4902 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
4903 env->log_type_id, t->name_off);
4904 return -EINVAL;
4905 }
4906
4907 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
4908 if (var_meta_size < 0)
4909 return var_meta_size;
4910
4911 meta_left -= var_meta_size;
4912
4913 return saved_meta_left - meta_left;
4914}
4915
4916static int btf_check_all_metas(struct btf_verifier_env *env)
4917{
4918 struct btf *btf = env->btf;
4919 struct btf_header *hdr;
4920 void *cur, *end;
4921
4922 hdr = &btf->hdr;
4923 cur = btf->nohdr_data + hdr->type_off;
4924 end = cur + hdr->type_len;
4925
4926 env->log_type_id = btf->base_btf ? btf->start_id : 1;
4927 while (cur < end) {
4928 struct btf_type *t = cur;
4929 s32 meta_size;
4930
4931 meta_size = btf_check_meta(env, t, end - cur);
4932 if (meta_size < 0)
4933 return meta_size;
4934
4935 btf_add_type(env, t);
4936 cur += meta_size;
4937 env->log_type_id++;
4938 }
4939
4940 return 0;
4941}
4942
4943static bool btf_resolve_valid(struct btf_verifier_env *env,
4944 const struct btf_type *t,
4945 u32 type_id)
4946{
4947 struct btf *btf = env->btf;
4948
4949 if (!env_type_is_resolved(env, type_id))
4950 return false;
4951
4952 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
4953 return !btf_resolved_type_id(btf, type_id) &&
4954 !btf_resolved_type_size(btf, type_id);
4955
4956 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
4957 return btf_resolved_type_id(btf, type_id) &&
4958 !btf_resolved_type_size(btf, type_id);
4959
4960 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
4961 btf_type_is_var(t)) {
4962 t = btf_type_id_resolve(btf, &type_id);
4963 return t &&
4964 !btf_type_is_modifier(t) &&
4965 !btf_type_is_var(t) &&
4966 !btf_type_is_datasec(t);
4967 }
4968
4969 if (btf_type_is_array(t)) {
4970 const struct btf_array *array = btf_type_array(t);
4971 const struct btf_type *elem_type;
4972 u32 elem_type_id = array->type;
4973 u32 elem_size;
4974
4975 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
4976 return elem_type && !btf_type_is_modifier(elem_type) &&
4977 (array->nelems * elem_size ==
4978 btf_resolved_type_size(btf, type_id));
4979 }
4980
4981 return false;
4982}
4983
4984static int btf_resolve(struct btf_verifier_env *env,
4985 const struct btf_type *t, u32 type_id)
4986{
4987 u32 save_log_type_id = env->log_type_id;
4988 const struct resolve_vertex *v;
4989 int err = 0;
4990
4991 env->resolve_mode = RESOLVE_TBD;
4992 env_stack_push(env, t, type_id);
4993 while (!err && (v = env_stack_peak(env))) {
4994 env->log_type_id = v->type_id;
4995 err = btf_type_ops(v->t)->resolve(env, v);
4996 }
4997
4998 env->log_type_id = type_id;
4999 if (err == -E2BIG) {
5000 btf_verifier_log_type(env, t,
5001 "Exceeded max resolving depth:%u",
5002 MAX_RESOLVE_DEPTH);
5003 } else if (err == -EEXIST) {
5004 btf_verifier_log_type(env, t, "Loop detected");
5005 }
5006
5007 /* Final sanity check */
5008 if (!err && !btf_resolve_valid(env, t, type_id)) {
5009 btf_verifier_log_type(env, t, "Invalid resolve state");
5010 err = -EINVAL;
5011 }
5012
5013 env->log_type_id = save_log_type_id;
5014 return err;
5015}
5016
5017static int btf_check_all_types(struct btf_verifier_env *env)
5018{
5019 struct btf *btf = env->btf;
5020 const struct btf_type *t;
5021 u32 type_id, i;
5022 int err;
5023
5024 err = env_resolve_init(env);
5025 if (err)
5026 return err;
5027
5028 env->phase++;
5029 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
5030 type_id = btf->start_id + i;
5031 t = btf_type_by_id(btf, type_id);
5032
5033 env->log_type_id = type_id;
5034 if (btf_type_needs_resolve(t) &&
5035 !env_type_is_resolved(env, type_id)) {
5036 err = btf_resolve(env, t, type_id);
5037 if (err)
5038 return err;
5039 }
5040
5041 if (btf_type_is_func_proto(t)) {
5042 err = btf_func_proto_check(env, t);
5043 if (err)
5044 return err;
5045 }
5046 }
5047
5048 return 0;
5049}
5050
5051static int btf_parse_type_sec(struct btf_verifier_env *env)
5052{
5053 const struct btf_header *hdr = &env->btf->hdr;
5054 int err;
5055
5056 /* Type section must align to 4 bytes */
5057 if (hdr->type_off & (sizeof(u32) - 1)) {
5058 btf_verifier_log(env, "Unaligned type_off");
5059 return -EINVAL;
5060 }
5061
5062 if (!env->btf->base_btf && !hdr->type_len) {
5063 btf_verifier_log(env, "No type found");
5064 return -EINVAL;
5065 }
5066
5067 err = btf_check_all_metas(env);
5068 if (err)
5069 return err;
5070
5071 return btf_check_all_types(env);
5072}
5073
5074static int btf_parse_str_sec(struct btf_verifier_env *env)
5075{
5076 const struct btf_header *hdr;
5077 struct btf *btf = env->btf;
5078 const char *start, *end;
5079
5080 hdr = &btf->hdr;
5081 start = btf->nohdr_data + hdr->str_off;
5082 end = start + hdr->str_len;
5083
5084 if (end != btf->data + btf->data_size) {
5085 btf_verifier_log(env, "String section is not at the end");
5086 return -EINVAL;
5087 }
5088
5089 btf->strings = start;
5090
5091 if (btf->base_btf && !hdr->str_len)
5092 return 0;
5093 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
5094 btf_verifier_log(env, "Invalid string section");
5095 return -EINVAL;
5096 }
5097 if (!btf->base_btf && start[0]) {
5098 btf_verifier_log(env, "Invalid string section");
5099 return -EINVAL;
5100 }
5101
5102 return 0;
5103}
5104
5105static const size_t btf_sec_info_offset[] = {
5106 offsetof(struct btf_header, type_off),
5107 offsetof(struct btf_header, str_off),
5108};
5109
5110static int btf_sec_info_cmp(const void *a, const void *b)
5111{
5112 const struct btf_sec_info *x = a;
5113 const struct btf_sec_info *y = b;
5114
5115 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
5116}
5117
5118static int btf_check_sec_info(struct btf_verifier_env *env,
5119 u32 btf_data_size)
5120{
5121 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
5122 u32 total, expected_total, i;
5123 const struct btf_header *hdr;
5124 const struct btf *btf;
5125
5126 btf = env->btf;
5127 hdr = &btf->hdr;
5128
5129 /* Populate the secs from hdr */
5130 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
5131 secs[i] = *(struct btf_sec_info *)((void *)hdr +
5132 btf_sec_info_offset[i]);
5133
5134 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
5135 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
5136
5137 /* Check for gaps and overlap among sections */
5138 total = 0;
5139 expected_total = btf_data_size - hdr->hdr_len;
5140 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
5141 if (expected_total < secs[i].off) {
5142 btf_verifier_log(env, "Invalid section offset");
5143 return -EINVAL;
5144 }
5145 if (total < secs[i].off) {
5146 /* gap */
5147 btf_verifier_log(env, "Unsupported section found");
5148 return -EINVAL;
5149 }
5150 if (total > secs[i].off) {
5151 btf_verifier_log(env, "Section overlap found");
5152 return -EINVAL;
5153 }
5154 if (expected_total - total < secs[i].len) {
5155 btf_verifier_log(env,
5156 "Total section length too long");
5157 return -EINVAL;
5158 }
5159 total += secs[i].len;
5160 }
5161
5162 /* There is data other than hdr and known sections */
5163 if (expected_total != total) {
5164 btf_verifier_log(env, "Unsupported section found");
5165 return -EINVAL;
5166 }
5167
5168 return 0;
5169}
5170
5171static int btf_parse_hdr(struct btf_verifier_env *env)
5172{
5173 u32 hdr_len, hdr_copy, btf_data_size;
5174 const struct btf_header *hdr;
5175 struct btf *btf;
5176
5177 btf = env->btf;
5178 btf_data_size = btf->data_size;
5179
5180 if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
5181 btf_verifier_log(env, "hdr_len not found");
5182 return -EINVAL;
5183 }
5184
5185 hdr = btf->data;
5186 hdr_len = hdr->hdr_len;
5187 if (btf_data_size < hdr_len) {
5188 btf_verifier_log(env, "btf_header not found");
5189 return -EINVAL;
5190 }
5191
5192 /* Ensure the unsupported header fields are zero */
5193 if (hdr_len > sizeof(btf->hdr)) {
5194 u8 *expected_zero = btf->data + sizeof(btf->hdr);
5195 u8 *end = btf->data + hdr_len;
5196
5197 for (; expected_zero < end; expected_zero++) {
5198 if (*expected_zero) {
5199 btf_verifier_log(env, "Unsupported btf_header");
5200 return -E2BIG;
5201 }
5202 }
5203 }
5204
5205 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
5206 memcpy(&btf->hdr, btf->data, hdr_copy);
5207
5208 hdr = &btf->hdr;
5209
5210 btf_verifier_log_hdr(env, btf_data_size);
5211
5212 if (hdr->magic != BTF_MAGIC) {
5213 btf_verifier_log(env, "Invalid magic");
5214 return -EINVAL;
5215 }
5216
5217 if (hdr->version != BTF_VERSION) {
5218 btf_verifier_log(env, "Unsupported version");
5219 return -ENOTSUPP;
5220 }
5221
5222 if (hdr->flags) {
5223 btf_verifier_log(env, "Unsupported flags");
5224 return -ENOTSUPP;
5225 }
5226
5227 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
5228 btf_verifier_log(env, "No data");
5229 return -EINVAL;
5230 }
5231
5232 return btf_check_sec_info(env, btf_data_size);
5233}
5234
5235static const char *alloc_obj_fields[] = {
5236 "bpf_spin_lock",
5237 "bpf_list_head",
5238 "bpf_list_node",
5239};
5240
5241static struct btf_struct_metas *
5242btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
5243{
5244 union {
5245 struct btf_id_set set;
5246 struct {
5247 u32 _cnt;
5248 u32 _ids[ARRAY_SIZE(alloc_obj_fields)];
5249 } _arr;
5250 } aof;
5251 struct btf_struct_metas *tab = NULL;
5252 int i, n, id, ret;
5253
5254 BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
5255 BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
5256
5257 memset(&aof, 0, sizeof(aof));
5258 for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
5259 /* Try to find whether this special type exists in user BTF, and
5260 * if so remember its ID so we can easily find it among members
5261 * of structs that we iterate in the next loop.
5262 */
5263 id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
5264 if (id < 0)
5265 continue;
5266 aof.set.ids[aof.set.cnt++] = id;
5267 }
5268
5269 if (!aof.set.cnt)
5270 return NULL;
5271 sort(&aof.set.ids, aof.set.cnt, sizeof(aof.set.ids[0]), btf_id_cmp_func, NULL);
5272
5273 n = btf_nr_types(btf);
5274 for (i = 1; i < n; i++) {
5275 struct btf_struct_metas *new_tab;
5276 const struct btf_member *member;
5277 struct btf_field_offs *foffs;
5278 struct btf_struct_meta *type;
5279 struct btf_record *record;
5280 const struct btf_type *t;
5281 int j, tab_cnt;
5282
5283 t = btf_type_by_id(btf, i);
5284 if (!t) {
5285 ret = -EINVAL;
5286 goto free;
5287 }
5288 if (!__btf_type_is_struct(t))
5289 continue;
5290
5291 cond_resched();
5292
5293 for_each_member(j, t, member) {
5294 if (btf_id_set_contains(&aof.set, member->type))
5295 goto parse;
5296 }
5297 continue;
5298 parse:
5299 tab_cnt = tab ? tab->cnt : 0;
5300 new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),
5301 GFP_KERNEL | __GFP_NOWARN);
5302 if (!new_tab) {
5303 ret = -ENOMEM;
5304 goto free;
5305 }
5306 if (!tab)
5307 new_tab->cnt = 0;
5308 tab = new_tab;
5309
5310 type = &tab->types[tab->cnt];
5311 type->btf_id = i;
5312 record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE, t->size);
5313 /* The record cannot be unset, treat it as an error if so */
5314 if (IS_ERR_OR_NULL(record)) {
5315 ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
5316 goto free;
5317 }
5318 foffs = btf_parse_field_offs(record);
5319 /* We need the field_offs to be valid for a valid record,
5320 * either both should be set or both should be unset.
5321 */
5322 if (IS_ERR_OR_NULL(foffs)) {
5323 btf_record_free(record);
5324 ret = -EFAULT;
5325 goto free;
5326 }
5327 type->record = record;
5328 type->field_offs = foffs;
5329 tab->cnt++;
5330 }
5331 return tab;
5332free:
5333 btf_struct_metas_free(tab);
5334 return ERR_PTR(ret);
5335}
5336
5337struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
5338{
5339 struct btf_struct_metas *tab;
5340
5341 BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
5342 tab = btf->struct_meta_tab;
5343 if (!tab)
5344 return NULL;
5345 return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
5346}
5347
5348static int btf_check_type_tags(struct btf_verifier_env *env,
5349 struct btf *btf, int start_id)
5350{
5351 int i, n, good_id = start_id - 1;
5352 bool in_tags;
5353
5354 n = btf_nr_types(btf);
5355 for (i = start_id; i < n; i++) {
5356 const struct btf_type *t;
5357 int chain_limit = 32;
5358 u32 cur_id = i;
5359
5360 t = btf_type_by_id(btf, i);
5361 if (!t)
5362 return -EINVAL;
5363 if (!btf_type_is_modifier(t))
5364 continue;
5365
5366 cond_resched();
5367
5368 in_tags = btf_type_is_type_tag(t);
5369 while (btf_type_is_modifier(t)) {
5370 if (!chain_limit--) {
5371 btf_verifier_log(env, "Max chain length or cycle detected");
5372 return -ELOOP;
5373 }
5374 if (btf_type_is_type_tag(t)) {
5375 if (!in_tags) {
5376 btf_verifier_log(env, "Type tags don't precede modifiers");
5377 return -EINVAL;
5378 }
5379 } else if (in_tags) {
5380 in_tags = false;
5381 }
5382 if (cur_id <= good_id)
5383 break;
5384 /* Move to next type */
5385 cur_id = t->type;
5386 t = btf_type_by_id(btf, cur_id);
5387 if (!t)
5388 return -EINVAL;
5389 }
5390 good_id = i;
5391 }
5392 return 0;
5393}
5394
5395static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
5396 u32 log_level, char __user *log_ubuf, u32 log_size)
5397{
5398 struct btf_struct_metas *struct_meta_tab;
5399 struct btf_verifier_env *env = NULL;
5400 struct bpf_verifier_log *log;
5401 struct btf *btf = NULL;
5402 u8 *data;
5403 int err;
5404
5405 if (btf_data_size > BTF_MAX_SIZE)
5406 return ERR_PTR(-E2BIG);
5407
5408 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5409 if (!env)
5410 return ERR_PTR(-ENOMEM);
5411
5412 log = &env->log;
5413 if (log_level || log_ubuf || log_size) {
5414 /* user requested verbose verifier output
5415 * and supplied buffer to store the verification trace
5416 */
5417 log->level = log_level;
5418 log->ubuf = log_ubuf;
5419 log->len_total = log_size;
5420
5421 /* log attributes have to be sane */
5422 if (!bpf_verifier_log_attr_valid(log)) {
5423 err = -EINVAL;
5424 goto errout;
5425 }
5426 }
5427
5428 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5429 if (!btf) {
5430 err = -ENOMEM;
5431 goto errout;
5432 }
5433 env->btf = btf;
5434
5435 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
5436 if (!data) {
5437 err = -ENOMEM;
5438 goto errout;
5439 }
5440
5441 btf->data = data;
5442 btf->data_size = btf_data_size;
5443
5444 if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
5445 err = -EFAULT;
5446 goto errout;
5447 }
5448
5449 err = btf_parse_hdr(env);
5450 if (err)
5451 goto errout;
5452
5453 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5454
5455 err = btf_parse_str_sec(env);
5456 if (err)
5457 goto errout;
5458
5459 err = btf_parse_type_sec(env);
5460 if (err)
5461 goto errout;
5462
5463 err = btf_check_type_tags(env, btf, 1);
5464 if (err)
5465 goto errout;
5466
5467 struct_meta_tab = btf_parse_struct_metas(log, btf);
5468 if (IS_ERR(struct_meta_tab)) {
5469 err = PTR_ERR(struct_meta_tab);
5470 goto errout;
5471 }
5472 btf->struct_meta_tab = struct_meta_tab;
5473
5474 if (struct_meta_tab) {
5475 int i;
5476
5477 for (i = 0; i < struct_meta_tab->cnt; i++) {
5478 err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
5479 if (err < 0)
5480 goto errout_meta;
5481 }
5482 }
5483
5484 if (log->level && bpf_verifier_log_full(log)) {
5485 err = -ENOSPC;
5486 goto errout_meta;
5487 }
5488
5489 btf_verifier_env_free(env);
5490 refcount_set(&btf->refcnt, 1);
5491 return btf;
5492
5493errout_meta:
5494 btf_free_struct_meta_tab(btf);
5495errout:
5496 btf_verifier_env_free(env);
5497 if (btf)
5498 btf_free(btf);
5499 return ERR_PTR(err);
5500}
5501
5502extern char __weak __start_BTF[];
5503extern char __weak __stop_BTF[];
5504extern struct btf *btf_vmlinux;
5505
5506#define BPF_MAP_TYPE(_id, _ops)
5507#define BPF_LINK_TYPE(_id, _name)
5508static union {
5509 struct bpf_ctx_convert {
5510#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5511 prog_ctx_type _id##_prog; \
5512 kern_ctx_type _id##_kern;
5513#include <linux/bpf_types.h>
5514#undef BPF_PROG_TYPE
5515 } *__t;
5516 /* 't' is written once under lock. Read many times. */
5517 const struct btf_type *t;
5518} bpf_ctx_convert;
5519enum {
5520#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5521 __ctx_convert##_id,
5522#include <linux/bpf_types.h>
5523#undef BPF_PROG_TYPE
5524 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
5525};
5526static u8 bpf_ctx_convert_map[] = {
5527#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5528 [_id] = __ctx_convert##_id,
5529#include <linux/bpf_types.h>
5530#undef BPF_PROG_TYPE
5531 0, /* avoid empty array */
5532};
5533#undef BPF_MAP_TYPE
5534#undef BPF_LINK_TYPE
5535
5536const struct btf_member *
5537btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5538 const struct btf_type *t, enum bpf_prog_type prog_type,
5539 int arg)
5540{
5541 const struct btf_type *conv_struct;
5542 const struct btf_type *ctx_struct;
5543 const struct btf_member *ctx_type;
5544 const char *tname, *ctx_tname;
5545
5546 conv_struct = bpf_ctx_convert.t;
5547 if (!conv_struct) {
5548 bpf_log(log, "btf_vmlinux is malformed\n");
5549 return NULL;
5550 }
5551 t = btf_type_by_id(btf, t->type);
5552 while (btf_type_is_modifier(t))
5553 t = btf_type_by_id(btf, t->type);
5554 if (!btf_type_is_struct(t)) {
5555 /* Only pointer to struct is supported for now.
5556 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5557 * is not supported yet.
5558 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5559 */
5560 return NULL;
5561 }
5562 tname = btf_name_by_offset(btf, t->name_off);
5563 if (!tname) {
5564 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5565 return NULL;
5566 }
5567 /* prog_type is valid bpf program type. No need for bounds check. */
5568 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5569 /* ctx_struct is a pointer to prog_ctx_type in vmlinux.
5570 * Like 'struct __sk_buff'
5571 */
5572 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
5573 if (!ctx_struct)
5574 /* should not happen */
5575 return NULL;
5576 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
5577 if (!ctx_tname) {
5578 /* should not happen */
5579 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
5580 return NULL;
5581 }
5582 /* only compare that prog's ctx type name is the same as
5583 * kernel expects. No need to compare field by field.
5584 * It's ok for bpf prog to do:
5585 * struct __sk_buff {};
5586 * int socket_filter_bpf_prog(struct __sk_buff *skb)
5587 * { // no fields of skb are ever used }
5588 */
5589 if (strcmp(ctx_tname, tname))
5590 return NULL;
5591 return ctx_type;
5592}
5593
5594static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
5595 struct btf *btf,
5596 const struct btf_type *t,
5597 enum bpf_prog_type prog_type,
5598 int arg)
5599{
5600 const struct btf_member *prog_ctx_type, *kern_ctx_type;
5601
5602 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
5603 if (!prog_ctx_type)
5604 return -ENOENT;
5605 kern_ctx_type = prog_ctx_type + 1;
5606 return kern_ctx_type->type;
5607}
5608
5609int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type)
5610{
5611 const struct btf_member *kctx_member;
5612 const struct btf_type *conv_struct;
5613 const struct btf_type *kctx_type;
5614 u32 kctx_type_id;
5615
5616 conv_struct = bpf_ctx_convert.t;
5617 /* get member for kernel ctx type */
5618 kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5619 kctx_type_id = kctx_member->type;
5620 kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id);
5621 if (!btf_type_is_struct(kctx_type)) {
5622 bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id);
5623 return -EINVAL;
5624 }
5625
5626 return kctx_type_id;
5627}
5628
5629BTF_ID_LIST(bpf_ctx_convert_btf_id)
5630BTF_ID(struct, bpf_ctx_convert)
5631
5632struct btf *btf_parse_vmlinux(void)
5633{
5634 struct btf_verifier_env *env = NULL;
5635 struct bpf_verifier_log *log;
5636 struct btf *btf = NULL;
5637 int err;
5638
5639 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5640 if (!env)
5641 return ERR_PTR(-ENOMEM);
5642
5643 log = &env->log;
5644 log->level = BPF_LOG_KERNEL;
5645
5646 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5647 if (!btf) {
5648 err = -ENOMEM;
5649 goto errout;
5650 }
5651 env->btf = btf;
5652
5653 btf->data = __start_BTF;
5654 btf->data_size = __stop_BTF - __start_BTF;
5655 btf->kernel_btf = true;
5656 snprintf(btf->name, sizeof(btf->name), "vmlinux");
5657
5658 err = btf_parse_hdr(env);
5659 if (err)
5660 goto errout;
5661
5662 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5663
5664 err = btf_parse_str_sec(env);
5665 if (err)
5666 goto errout;
5667
5668 err = btf_check_all_metas(env);
5669 if (err)
5670 goto errout;
5671
5672 err = btf_check_type_tags(env, btf, 1);
5673 if (err)
5674 goto errout;
5675
5676 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
5677 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
5678
5679 bpf_struct_ops_init(btf, log);
5680
5681 refcount_set(&btf->refcnt, 1);
5682
5683 err = btf_alloc_id(btf);
5684 if (err)
5685 goto errout;
5686
5687 btf_verifier_env_free(env);
5688 return btf;
5689
5690errout:
5691 btf_verifier_env_free(env);
5692 if (btf) {
5693 kvfree(btf->types);
5694 kfree(btf);
5695 }
5696 return ERR_PTR(err);
5697}
5698
5699#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
5700
5701static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
5702{
5703 struct btf_verifier_env *env = NULL;
5704 struct bpf_verifier_log *log;
5705 struct btf *btf = NULL, *base_btf;
5706 int err;
5707
5708 base_btf = bpf_get_btf_vmlinux();
5709 if (IS_ERR(base_btf))
5710 return base_btf;
5711 if (!base_btf)
5712 return ERR_PTR(-EINVAL);
5713
5714 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5715 if (!env)
5716 return ERR_PTR(-ENOMEM);
5717
5718 log = &env->log;
5719 log->level = BPF_LOG_KERNEL;
5720
5721 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5722 if (!btf) {
5723 err = -ENOMEM;
5724 goto errout;
5725 }
5726 env->btf = btf;
5727
5728 btf->base_btf = base_btf;
5729 btf->start_id = base_btf->nr_types;
5730 btf->start_str_off = base_btf->hdr.str_len;
5731 btf->kernel_btf = true;
5732 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
5733
5734 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
5735 if (!btf->data) {
5736 err = -ENOMEM;
5737 goto errout;
5738 }
5739 memcpy(btf->data, data, data_size);
5740 btf->data_size = data_size;
5741
5742 err = btf_parse_hdr(env);
5743 if (err)
5744 goto errout;
5745
5746 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5747
5748 err = btf_parse_str_sec(env);
5749 if (err)
5750 goto errout;
5751
5752 err = btf_check_all_metas(env);
5753 if (err)
5754 goto errout;
5755
5756 err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
5757 if (err)
5758 goto errout;
5759
5760 btf_verifier_env_free(env);
5761 refcount_set(&btf->refcnt, 1);
5762 return btf;
5763
5764errout:
5765 btf_verifier_env_free(env);
5766 if (btf) {
5767 kvfree(btf->data);
5768 kvfree(btf->types);
5769 kfree(btf);
5770 }
5771 return ERR_PTR(err);
5772}
5773
5774#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
5775
5776struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
5777{
5778 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
5779
5780 if (tgt_prog)
5781 return tgt_prog->aux->btf;
5782 else
5783 return prog->aux->attach_btf;
5784}
5785
5786static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
5787{
5788 /* t comes in already as a pointer */
5789 t = btf_type_by_id(btf, t->type);
5790
5791 /* allow const */
5792 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST)
5793 t = btf_type_by_id(btf, t->type);
5794
5795 return btf_type_is_int(t);
5796}
5797
5798static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
5799 int off)
5800{
5801 const struct btf_param *args;
5802 const struct btf_type *t;
5803 u32 offset = 0, nr_args;
5804 int i;
5805
5806 if (!func_proto)
5807 return off / 8;
5808
5809 nr_args = btf_type_vlen(func_proto);
5810 args = (const struct btf_param *)(func_proto + 1);
5811 for (i = 0; i < nr_args; i++) {
5812 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
5813 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
5814 if (off < offset)
5815 return i;
5816 }
5817
5818 t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
5819 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
5820 if (off < offset)
5821 return nr_args;
5822
5823 return nr_args + 1;
5824}
5825
5826static bool prog_args_trusted(const struct bpf_prog *prog)
5827{
5828 enum bpf_attach_type atype = prog->expected_attach_type;
5829
5830 switch (prog->type) {
5831 case BPF_PROG_TYPE_TRACING:
5832 return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER;
5833 case BPF_PROG_TYPE_LSM:
5834 return bpf_lsm_is_trusted(prog);
5835 case BPF_PROG_TYPE_STRUCT_OPS:
5836 return true;
5837 default:
5838 return false;
5839 }
5840}
5841
5842bool btf_ctx_access(int off, int size, enum bpf_access_type type,
5843 const struct bpf_prog *prog,
5844 struct bpf_insn_access_aux *info)
5845{
5846 const struct btf_type *t = prog->aux->attach_func_proto;
5847 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
5848 struct btf *btf = bpf_prog_get_target_btf(prog);
5849 const char *tname = prog->aux->attach_func_name;
5850 struct bpf_verifier_log *log = info->log;
5851 const struct btf_param *args;
5852 const char *tag_value;
5853 u32 nr_args, arg;
5854 int i, ret;
5855
5856 if (off % 8) {
5857 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
5858 tname, off);
5859 return false;
5860 }
5861 arg = get_ctx_arg_idx(btf, t, off);
5862 args = (const struct btf_param *)(t + 1);
5863 /* if (t == NULL) Fall back to default BPF prog with
5864 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
5865 */
5866 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
5867 if (prog->aux->attach_btf_trace) {
5868 /* skip first 'void *__data' argument in btf_trace_##name typedef */
5869 args++;
5870 nr_args--;
5871 }
5872
5873 if (arg > nr_args) {
5874 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
5875 tname, arg + 1);
5876 return false;
5877 }
5878
5879 if (arg == nr_args) {
5880 switch (prog->expected_attach_type) {
5881 case BPF_LSM_CGROUP:
5882 case BPF_LSM_MAC:
5883 case BPF_TRACE_FEXIT:
5884 /* When LSM programs are attached to void LSM hooks
5885 * they use FEXIT trampolines and when attached to
5886 * int LSM hooks, they use MODIFY_RETURN trampolines.
5887 *
5888 * While the LSM programs are BPF_MODIFY_RETURN-like
5889 * the check:
5890 *
5891 * if (ret_type != 'int')
5892 * return -EINVAL;
5893 *
5894 * is _not_ done here. This is still safe as LSM hooks
5895 * have only void and int return types.
5896 */
5897 if (!t)
5898 return true;
5899 t = btf_type_by_id(btf, t->type);
5900 break;
5901 case BPF_MODIFY_RETURN:
5902 /* For now the BPF_MODIFY_RETURN can only be attached to
5903 * functions that return an int.
5904 */
5905 if (!t)
5906 return false;
5907
5908 t = btf_type_skip_modifiers(btf, t->type, NULL);
5909 if (!btf_type_is_small_int(t)) {
5910 bpf_log(log,
5911 "ret type %s not allowed for fmod_ret\n",
5912 btf_type_str(t));
5913 return false;
5914 }
5915 break;
5916 default:
5917 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
5918 tname, arg + 1);
5919 return false;
5920 }
5921 } else {
5922 if (!t)
5923 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
5924 return true;
5925 t = btf_type_by_id(btf, args[arg].type);
5926 }
5927
5928 /* skip modifiers */
5929 while (btf_type_is_modifier(t))
5930 t = btf_type_by_id(btf, t->type);
5931 if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
5932 /* accessing a scalar */
5933 return true;
5934 if (!btf_type_is_ptr(t)) {
5935 bpf_log(log,
5936 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
5937 tname, arg,
5938 __btf_name_by_offset(btf, t->name_off),
5939 btf_type_str(t));
5940 return false;
5941 }
5942
5943 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
5944 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5945 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5946 u32 type, flag;
5947
5948 type = base_type(ctx_arg_info->reg_type);
5949 flag = type_flag(ctx_arg_info->reg_type);
5950 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
5951 (flag & PTR_MAYBE_NULL)) {
5952 info->reg_type = ctx_arg_info->reg_type;
5953 return true;
5954 }
5955 }
5956
5957 if (t->type == 0)
5958 /* This is a pointer to void.
5959 * It is the same as scalar from the verifier safety pov.
5960 * No further pointer walking is allowed.
5961 */
5962 return true;
5963
5964 if (is_int_ptr(btf, t))
5965 return true;
5966
5967 /* this is a pointer to another type */
5968 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5969 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5970
5971 if (ctx_arg_info->offset == off) {
5972 if (!ctx_arg_info->btf_id) {
5973 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
5974 return false;
5975 }
5976
5977 info->reg_type = ctx_arg_info->reg_type;
5978 info->btf = btf_vmlinux;
5979 info->btf_id = ctx_arg_info->btf_id;
5980 return true;
5981 }
5982 }
5983
5984 info->reg_type = PTR_TO_BTF_ID;
5985 if (prog_args_trusted(prog))
5986 info->reg_type |= PTR_TRUSTED;
5987
5988 if (tgt_prog) {
5989 enum bpf_prog_type tgt_type;
5990
5991 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
5992 tgt_type = tgt_prog->aux->saved_dst_prog_type;
5993 else
5994 tgt_type = tgt_prog->type;
5995
5996 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
5997 if (ret > 0) {
5998 info->btf = btf_vmlinux;
5999 info->btf_id = ret;
6000 return true;
6001 } else {
6002 return false;
6003 }
6004 }
6005
6006 info->btf = btf;
6007 info->btf_id = t->type;
6008 t = btf_type_by_id(btf, t->type);
6009
6010 if (btf_type_is_type_tag(t)) {
6011 tag_value = __btf_name_by_offset(btf, t->name_off);
6012 if (strcmp(tag_value, "user") == 0)
6013 info->reg_type |= MEM_USER;
6014 if (strcmp(tag_value, "percpu") == 0)
6015 info->reg_type |= MEM_PERCPU;
6016 }
6017
6018 /* skip modifiers */
6019 while (btf_type_is_modifier(t)) {
6020 info->btf_id = t->type;
6021 t = btf_type_by_id(btf, t->type);
6022 }
6023 if (!btf_type_is_struct(t)) {
6024 bpf_log(log,
6025 "func '%s' arg%d type %s is not a struct\n",
6026 tname, arg, btf_type_str(t));
6027 return false;
6028 }
6029 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
6030 tname, arg, info->btf_id, btf_type_str(t),
6031 __btf_name_by_offset(btf, t->name_off));
6032 return true;
6033}
6034
6035enum bpf_struct_walk_result {
6036 /* < 0 error */
6037 WALK_SCALAR = 0,
6038 WALK_PTR,
6039 WALK_STRUCT,
6040};
6041
6042static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
6043 const struct btf_type *t, int off, int size,
6044 u32 *next_btf_id, enum bpf_type_flag *flag)
6045{
6046 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
6047 const struct btf_type *mtype, *elem_type = NULL;
6048 const struct btf_member *member;
6049 const char *tname, *mname, *tag_value;
6050 u32 vlen, elem_id, mid;
6051
6052again:
6053 tname = __btf_name_by_offset(btf, t->name_off);
6054 if (!btf_type_is_struct(t)) {
6055 bpf_log(log, "Type '%s' is not a struct\n", tname);
6056 return -EINVAL;
6057 }
6058
6059 vlen = btf_type_vlen(t);
6060 if (off + size > t->size) {
6061 /* If the last element is a variable size array, we may
6062 * need to relax the rule.
6063 */
6064 struct btf_array *array_elem;
6065
6066 if (vlen == 0)
6067 goto error;
6068
6069 member = btf_type_member(t) + vlen - 1;
6070 mtype = btf_type_skip_modifiers(btf, member->type,
6071 NULL);
6072 if (!btf_type_is_array(mtype))
6073 goto error;
6074
6075 array_elem = (struct btf_array *)(mtype + 1);
6076 if (array_elem->nelems != 0)
6077 goto error;
6078
6079 moff = __btf_member_bit_offset(t, member) / 8;
6080 if (off < moff)
6081 goto error;
6082
6083 /* Only allow structure for now, can be relaxed for
6084 * other types later.
6085 */
6086 t = btf_type_skip_modifiers(btf, array_elem->type,
6087 NULL);
6088 if (!btf_type_is_struct(t))
6089 goto error;
6090
6091 off = (off - moff) % t->size;
6092 goto again;
6093
6094error:
6095 bpf_log(log, "access beyond struct %s at off %u size %u\n",
6096 tname, off, size);
6097 return -EACCES;
6098 }
6099
6100 for_each_member(i, t, member) {
6101 /* offset of the field in bytes */
6102 moff = __btf_member_bit_offset(t, member) / 8;
6103 if (off + size <= moff)
6104 /* won't find anything, field is already too far */
6105 break;
6106
6107 if (__btf_member_bitfield_size(t, member)) {
6108 u32 end_bit = __btf_member_bit_offset(t, member) +
6109 __btf_member_bitfield_size(t, member);
6110
6111 /* off <= moff instead of off == moff because clang
6112 * does not generate a BTF member for anonymous
6113 * bitfield like the ":16" here:
6114 * struct {
6115 * int :16;
6116 * int x:8;
6117 * };
6118 */
6119 if (off <= moff &&
6120 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
6121 return WALK_SCALAR;
6122
6123 /* off may be accessing a following member
6124 *
6125 * or
6126 *
6127 * Doing partial access at either end of this
6128 * bitfield. Continue on this case also to
6129 * treat it as not accessing this bitfield
6130 * and eventually error out as field not
6131 * found to keep it simple.
6132 * It could be relaxed if there was a legit
6133 * partial access case later.
6134 */
6135 continue;
6136 }
6137
6138 /* In case of "off" is pointing to holes of a struct */
6139 if (off < moff)
6140 break;
6141
6142 /* type of the field */
6143 mid = member->type;
6144 mtype = btf_type_by_id(btf, member->type);
6145 mname = __btf_name_by_offset(btf, member->name_off);
6146
6147 mtype = __btf_resolve_size(btf, mtype, &msize,
6148 &elem_type, &elem_id, &total_nelems,
6149 &mid);
6150 if (IS_ERR(mtype)) {
6151 bpf_log(log, "field %s doesn't have size\n", mname);
6152 return -EFAULT;
6153 }
6154
6155 mtrue_end = moff + msize;
6156 if (off >= mtrue_end)
6157 /* no overlap with member, keep iterating */
6158 continue;
6159
6160 if (btf_type_is_array(mtype)) {
6161 u32 elem_idx;
6162
6163 /* __btf_resolve_size() above helps to
6164 * linearize a multi-dimensional array.
6165 *
6166 * The logic here is treating an array
6167 * in a struct as the following way:
6168 *
6169 * struct outer {
6170 * struct inner array[2][2];
6171 * };
6172 *
6173 * looks like:
6174 *
6175 * struct outer {
6176 * struct inner array_elem0;
6177 * struct inner array_elem1;
6178 * struct inner array_elem2;
6179 * struct inner array_elem3;
6180 * };
6181 *
6182 * When accessing outer->array[1][0], it moves
6183 * moff to "array_elem2", set mtype to
6184 * "struct inner", and msize also becomes
6185 * sizeof(struct inner). Then most of the
6186 * remaining logic will fall through without
6187 * caring the current member is an array or
6188 * not.
6189 *
6190 * Unlike mtype/msize/moff, mtrue_end does not
6191 * change. The naming difference ("_true") tells
6192 * that it is not always corresponding to
6193 * the current mtype/msize/moff.
6194 * It is the true end of the current
6195 * member (i.e. array in this case). That
6196 * will allow an int array to be accessed like
6197 * a scratch space,
6198 * i.e. allow access beyond the size of
6199 * the array's element as long as it is
6200 * within the mtrue_end boundary.
6201 */
6202
6203 /* skip empty array */
6204 if (moff == mtrue_end)
6205 continue;
6206
6207 msize /= total_nelems;
6208 elem_idx = (off - moff) / msize;
6209 moff += elem_idx * msize;
6210 mtype = elem_type;
6211 mid = elem_id;
6212 }
6213
6214 /* the 'off' we're looking for is either equal to start
6215 * of this field or inside of this struct
6216 */
6217 if (btf_type_is_struct(mtype)) {
6218 /* our field must be inside that union or struct */
6219 t = mtype;
6220
6221 /* return if the offset matches the member offset */
6222 if (off == moff) {
6223 *next_btf_id = mid;
6224 return WALK_STRUCT;
6225 }
6226
6227 /* adjust offset we're looking for */
6228 off -= moff;
6229 goto again;
6230 }
6231
6232 if (btf_type_is_ptr(mtype)) {
6233 const struct btf_type *stype, *t;
6234 enum bpf_type_flag tmp_flag = 0;
6235 u32 id;
6236
6237 if (msize != size || off != moff) {
6238 bpf_log(log,
6239 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
6240 mname, moff, tname, off, size);
6241 return -EACCES;
6242 }
6243
6244 /* check type tag */
6245 t = btf_type_by_id(btf, mtype->type);
6246 if (btf_type_is_type_tag(t)) {
6247 tag_value = __btf_name_by_offset(btf, t->name_off);
6248 /* check __user tag */
6249 if (strcmp(tag_value, "user") == 0)
6250 tmp_flag = MEM_USER;
6251 /* check __percpu tag */
6252 if (strcmp(tag_value, "percpu") == 0)
6253 tmp_flag = MEM_PERCPU;
6254 /* check __rcu tag */
6255 if (strcmp(tag_value, "rcu") == 0)
6256 tmp_flag = MEM_RCU;
6257 }
6258
6259 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
6260 if (btf_type_is_struct(stype)) {
6261 *next_btf_id = id;
6262 *flag = tmp_flag;
6263 return WALK_PTR;
6264 }
6265 }
6266
6267 /* Allow more flexible access within an int as long as
6268 * it is within mtrue_end.
6269 * Since mtrue_end could be the end of an array,
6270 * that also allows using an array of int as a scratch
6271 * space. e.g. skb->cb[].
6272 */
6273 if (off + size > mtrue_end) {
6274 bpf_log(log,
6275 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
6276 mname, mtrue_end, tname, off, size);
6277 return -EACCES;
6278 }
6279
6280 return WALK_SCALAR;
6281 }
6282 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
6283 return -EINVAL;
6284}
6285
6286int btf_struct_access(struct bpf_verifier_log *log,
6287 const struct bpf_reg_state *reg,
6288 int off, int size, enum bpf_access_type atype __maybe_unused,
6289 u32 *next_btf_id, enum bpf_type_flag *flag)
6290{
6291 const struct btf *btf = reg->btf;
6292 enum bpf_type_flag tmp_flag = 0;
6293 const struct btf_type *t;
6294 u32 id = reg->btf_id;
6295 int err;
6296
6297 while (type_is_alloc(reg->type)) {
6298 struct btf_struct_meta *meta;
6299 struct btf_record *rec;
6300 int i;
6301
6302 meta = btf_find_struct_meta(btf, id);
6303 if (!meta)
6304 break;
6305 rec = meta->record;
6306 for (i = 0; i < rec->cnt; i++) {
6307 struct btf_field *field = &rec->fields[i];
6308 u32 offset = field->offset;
6309 if (off < offset + btf_field_type_size(field->type) && offset < off + size) {
6310 bpf_log(log,
6311 "direct access to %s is disallowed\n",
6312 btf_field_type_name(field->type));
6313 return -EACCES;
6314 }
6315 }
6316 break;
6317 }
6318
6319 t = btf_type_by_id(btf, id);
6320 do {
6321 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
6322
6323 switch (err) {
6324 case WALK_PTR:
6325 /* For local types, the destination register cannot
6326 * become a pointer again.
6327 */
6328 if (type_is_alloc(reg->type))
6329 return SCALAR_VALUE;
6330 /* If we found the pointer or scalar on t+off,
6331 * we're done.
6332 */
6333 *next_btf_id = id;
6334 *flag = tmp_flag;
6335 return PTR_TO_BTF_ID;
6336 case WALK_SCALAR:
6337 return SCALAR_VALUE;
6338 case WALK_STRUCT:
6339 /* We found nested struct, so continue the search
6340 * by diving in it. At this point the offset is
6341 * aligned with the new type, so set it to 0.
6342 */
6343 t = btf_type_by_id(btf, id);
6344 off = 0;
6345 break;
6346 default:
6347 /* It's either error or unknown return value..
6348 * scream and leave.
6349 */
6350 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
6351 return -EINVAL;
6352 return err;
6353 }
6354 } while (t);
6355
6356 return -EINVAL;
6357}
6358
6359/* Check that two BTF types, each specified as an BTF object + id, are exactly
6360 * the same. Trivial ID check is not enough due to module BTFs, because we can
6361 * end up with two different module BTFs, but IDs point to the common type in
6362 * vmlinux BTF.
6363 */
6364bool btf_types_are_same(const struct btf *btf1, u32 id1,
6365 const struct btf *btf2, u32 id2)
6366{
6367 if (id1 != id2)
6368 return false;
6369 if (btf1 == btf2)
6370 return true;
6371 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
6372}
6373
6374bool btf_struct_ids_match(struct bpf_verifier_log *log,
6375 const struct btf *btf, u32 id, int off,
6376 const struct btf *need_btf, u32 need_type_id,
6377 bool strict)
6378{
6379 const struct btf_type *type;
6380 enum bpf_type_flag flag;
6381 int err;
6382
6383 /* Are we already done? */
6384 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
6385 return true;
6386 /* In case of strict type match, we do not walk struct, the top level
6387 * type match must succeed. When strict is true, off should have already
6388 * been 0.
6389 */
6390 if (strict)
6391 return false;
6392again:
6393 type = btf_type_by_id(btf, id);
6394 if (!type)
6395 return false;
6396 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag);
6397 if (err != WALK_STRUCT)
6398 return false;
6399
6400 /* We found nested struct object. If it matches
6401 * the requested ID, we're done. Otherwise let's
6402 * continue the search with offset 0 in the new
6403 * type.
6404 */
6405 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
6406 off = 0;
6407 goto again;
6408 }
6409
6410 return true;
6411}
6412
6413static int __get_type_size(struct btf *btf, u32 btf_id,
6414 const struct btf_type **ret_type)
6415{
6416 const struct btf_type *t;
6417
6418 *ret_type = btf_type_by_id(btf, 0);
6419 if (!btf_id)
6420 /* void */
6421 return 0;
6422 t = btf_type_by_id(btf, btf_id);
6423 while (t && btf_type_is_modifier(t))
6424 t = btf_type_by_id(btf, t->type);
6425 if (!t)
6426 return -EINVAL;
6427 *ret_type = t;
6428 if (btf_type_is_ptr(t))
6429 /* kernel size of pointer. Not BPF's size of pointer*/
6430 return sizeof(void *);
6431 if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6432 return t->size;
6433 return -EINVAL;
6434}
6435
6436int btf_distill_func_proto(struct bpf_verifier_log *log,
6437 struct btf *btf,
6438 const struct btf_type *func,
6439 const char *tname,
6440 struct btf_func_model *m)
6441{
6442 const struct btf_param *args;
6443 const struct btf_type *t;
6444 u32 i, nargs;
6445 int ret;
6446
6447 if (!func) {
6448 /* BTF function prototype doesn't match the verifier types.
6449 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
6450 */
6451 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
6452 m->arg_size[i] = 8;
6453 m->arg_flags[i] = 0;
6454 }
6455 m->ret_size = 8;
6456 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
6457 return 0;
6458 }
6459 args = (const struct btf_param *)(func + 1);
6460 nargs = btf_type_vlen(func);
6461 if (nargs > MAX_BPF_FUNC_ARGS) {
6462 bpf_log(log,
6463 "The function %s has %d arguments. Too many.\n",
6464 tname, nargs);
6465 return -EINVAL;
6466 }
6467 ret = __get_type_size(btf, func->type, &t);
6468 if (ret < 0 || __btf_type_is_struct(t)) {
6469 bpf_log(log,
6470 "The function %s return type %s is unsupported.\n",
6471 tname, btf_type_str(t));
6472 return -EINVAL;
6473 }
6474 m->ret_size = ret;
6475
6476 for (i = 0; i < nargs; i++) {
6477 if (i == nargs - 1 && args[i].type == 0) {
6478 bpf_log(log,
6479 "The function %s with variable args is unsupported.\n",
6480 tname);
6481 return -EINVAL;
6482 }
6483 ret = __get_type_size(btf, args[i].type, &t);
6484
6485 /* No support of struct argument size greater than 16 bytes */
6486 if (ret < 0 || ret > 16) {
6487 bpf_log(log,
6488 "The function %s arg%d type %s is unsupported.\n",
6489 tname, i, btf_type_str(t));
6490 return -EINVAL;
6491 }
6492 if (ret == 0) {
6493 bpf_log(log,
6494 "The function %s has malformed void argument.\n",
6495 tname);
6496 return -EINVAL;
6497 }
6498 m->arg_size[i] = ret;
6499 m->arg_flags[i] = __btf_type_is_struct(t) ? BTF_FMODEL_STRUCT_ARG : 0;
6500 }
6501 m->nr_args = nargs;
6502 return 0;
6503}
6504
6505/* Compare BTFs of two functions assuming only scalars and pointers to context.
6506 * t1 points to BTF_KIND_FUNC in btf1
6507 * t2 points to BTF_KIND_FUNC in btf2
6508 * Returns:
6509 * EINVAL - function prototype mismatch
6510 * EFAULT - verifier bug
6511 * 0 - 99% match. The last 1% is validated by the verifier.
6512 */
6513static int btf_check_func_type_match(struct bpf_verifier_log *log,
6514 struct btf *btf1, const struct btf_type *t1,
6515 struct btf *btf2, const struct btf_type *t2)
6516{
6517 const struct btf_param *args1, *args2;
6518 const char *fn1, *fn2, *s1, *s2;
6519 u32 nargs1, nargs2, i;
6520
6521 fn1 = btf_name_by_offset(btf1, t1->name_off);
6522 fn2 = btf_name_by_offset(btf2, t2->name_off);
6523
6524 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
6525 bpf_log(log, "%s() is not a global function\n", fn1);
6526 return -EINVAL;
6527 }
6528 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
6529 bpf_log(log, "%s() is not a global function\n", fn2);
6530 return -EINVAL;
6531 }
6532
6533 t1 = btf_type_by_id(btf1, t1->type);
6534 if (!t1 || !btf_type_is_func_proto(t1))
6535 return -EFAULT;
6536 t2 = btf_type_by_id(btf2, t2->type);
6537 if (!t2 || !btf_type_is_func_proto(t2))
6538 return -EFAULT;
6539
6540 args1 = (const struct btf_param *)(t1 + 1);
6541 nargs1 = btf_type_vlen(t1);
6542 args2 = (const struct btf_param *)(t2 + 1);
6543 nargs2 = btf_type_vlen(t2);
6544
6545 if (nargs1 != nargs2) {
6546 bpf_log(log, "%s() has %d args while %s() has %d args\n",
6547 fn1, nargs1, fn2, nargs2);
6548 return -EINVAL;
6549 }
6550
6551 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6552 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6553 if (t1->info != t2->info) {
6554 bpf_log(log,
6555 "Return type %s of %s() doesn't match type %s of %s()\n",
6556 btf_type_str(t1), fn1,
6557 btf_type_str(t2), fn2);
6558 return -EINVAL;
6559 }
6560
6561 for (i = 0; i < nargs1; i++) {
6562 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
6563 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
6564
6565 if (t1->info != t2->info) {
6566 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
6567 i, fn1, btf_type_str(t1),
6568 fn2, btf_type_str(t2));
6569 return -EINVAL;
6570 }
6571 if (btf_type_has_size(t1) && t1->size != t2->size) {
6572 bpf_log(log,
6573 "arg%d in %s() has size %d while %s() has %d\n",
6574 i, fn1, t1->size,
6575 fn2, t2->size);
6576 return -EINVAL;
6577 }
6578
6579 /* global functions are validated with scalars and pointers
6580 * to context only. And only global functions can be replaced.
6581 * Hence type check only those types.
6582 */
6583 if (btf_type_is_int(t1) || btf_is_any_enum(t1))
6584 continue;
6585 if (!btf_type_is_ptr(t1)) {
6586 bpf_log(log,
6587 "arg%d in %s() has unrecognized type\n",
6588 i, fn1);
6589 return -EINVAL;
6590 }
6591 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6592 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6593 if (!btf_type_is_struct(t1)) {
6594 bpf_log(log,
6595 "arg%d in %s() is not a pointer to context\n",
6596 i, fn1);
6597 return -EINVAL;
6598 }
6599 if (!btf_type_is_struct(t2)) {
6600 bpf_log(log,
6601 "arg%d in %s() is not a pointer to context\n",
6602 i, fn2);
6603 return -EINVAL;
6604 }
6605 /* This is an optional check to make program writing easier.
6606 * Compare names of structs and report an error to the user.
6607 * btf_prepare_func_args() already checked that t2 struct
6608 * is a context type. btf_prepare_func_args() will check
6609 * later that t1 struct is a context type as well.
6610 */
6611 s1 = btf_name_by_offset(btf1, t1->name_off);
6612 s2 = btf_name_by_offset(btf2, t2->name_off);
6613 if (strcmp(s1, s2)) {
6614 bpf_log(log,
6615 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
6616 i, fn1, s1, fn2, s2);
6617 return -EINVAL;
6618 }
6619 }
6620 return 0;
6621}
6622
6623/* Compare BTFs of given program with BTF of target program */
6624int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
6625 struct btf *btf2, const struct btf_type *t2)
6626{
6627 struct btf *btf1 = prog->aux->btf;
6628 const struct btf_type *t1;
6629 u32 btf_id = 0;
6630
6631 if (!prog->aux->func_info) {
6632 bpf_log(log, "Program extension requires BTF\n");
6633 return -EINVAL;
6634 }
6635
6636 btf_id = prog->aux->func_info[0].type_id;
6637 if (!btf_id)
6638 return -EFAULT;
6639
6640 t1 = btf_type_by_id(btf1, btf_id);
6641 if (!t1 || !btf_type_is_func(t1))
6642 return -EFAULT;
6643
6644 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
6645}
6646
6647static int btf_check_func_arg_match(struct bpf_verifier_env *env,
6648 const struct btf *btf, u32 func_id,
6649 struct bpf_reg_state *regs,
6650 bool ptr_to_mem_ok,
6651 bool processing_call)
6652{
6653 enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
6654 struct bpf_verifier_log *log = &env->log;
6655 const char *func_name, *ref_tname;
6656 const struct btf_type *t, *ref_t;
6657 const struct btf_param *args;
6658 u32 i, nargs, ref_id;
6659 int ret;
6660
6661 t = btf_type_by_id(btf, func_id);
6662 if (!t || !btf_type_is_func(t)) {
6663 /* These checks were already done by the verifier while loading
6664 * struct bpf_func_info or in add_kfunc_call().
6665 */
6666 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
6667 func_id);
6668 return -EFAULT;
6669 }
6670 func_name = btf_name_by_offset(btf, t->name_off);
6671
6672 t = btf_type_by_id(btf, t->type);
6673 if (!t || !btf_type_is_func_proto(t)) {
6674 bpf_log(log, "Invalid BTF of func %s\n", func_name);
6675 return -EFAULT;
6676 }
6677 args = (const struct btf_param *)(t + 1);
6678 nargs = btf_type_vlen(t);
6679 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6680 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
6681 MAX_BPF_FUNC_REG_ARGS);
6682 return -EINVAL;
6683 }
6684
6685 /* check that BTF function arguments match actual types that the
6686 * verifier sees.
6687 */
6688 for (i = 0; i < nargs; i++) {
6689 enum bpf_arg_type arg_type = ARG_DONTCARE;
6690 u32 regno = i + 1;
6691 struct bpf_reg_state *reg = ®s[regno];
6692
6693 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6694 if (btf_type_is_scalar(t)) {
6695 if (reg->type == SCALAR_VALUE)
6696 continue;
6697 bpf_log(log, "R%d is not a scalar\n", regno);
6698 return -EINVAL;
6699 }
6700
6701 if (!btf_type_is_ptr(t)) {
6702 bpf_log(log, "Unrecognized arg#%d type %s\n",
6703 i, btf_type_str(t));
6704 return -EINVAL;
6705 }
6706
6707 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
6708 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
6709
6710 ret = check_func_arg_reg_off(env, reg, regno, arg_type);
6711 if (ret < 0)
6712 return ret;
6713
6714 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
6715 /* If function expects ctx type in BTF check that caller
6716 * is passing PTR_TO_CTX.
6717 */
6718 if (reg->type != PTR_TO_CTX) {
6719 bpf_log(log,
6720 "arg#%d expected pointer to ctx, but got %s\n",
6721 i, btf_type_str(t));
6722 return -EINVAL;
6723 }
6724 } else if (ptr_to_mem_ok && processing_call) {
6725 const struct btf_type *resolve_ret;
6726 u32 type_size;
6727
6728 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
6729 if (IS_ERR(resolve_ret)) {
6730 bpf_log(log,
6731 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6732 i, btf_type_str(ref_t), ref_tname,
6733 PTR_ERR(resolve_ret));
6734 return -EINVAL;
6735 }
6736
6737 if (check_mem_reg(env, reg, regno, type_size))
6738 return -EINVAL;
6739 } else {
6740 bpf_log(log, "reg type unsupported for arg#%d function %s#%d\n", i,
6741 func_name, func_id);
6742 return -EINVAL;
6743 }
6744 }
6745
6746 return 0;
6747}
6748
6749/* Compare BTF of a function declaration with given bpf_reg_state.
6750 * Returns:
6751 * EFAULT - there is a verifier bug. Abort verification.
6752 * EINVAL - there is a type mismatch or BTF is not available.
6753 * 0 - BTF matches with what bpf_reg_state expects.
6754 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
6755 */
6756int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
6757 struct bpf_reg_state *regs)
6758{
6759 struct bpf_prog *prog = env->prog;
6760 struct btf *btf = prog->aux->btf;
6761 bool is_global;
6762 u32 btf_id;
6763 int err;
6764
6765 if (!prog->aux->func_info)
6766 return -EINVAL;
6767
6768 btf_id = prog->aux->func_info[subprog].type_id;
6769 if (!btf_id)
6770 return -EFAULT;
6771
6772 if (prog->aux->func_info_aux[subprog].unreliable)
6773 return -EINVAL;
6774
6775 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
6776 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, false);
6777
6778 /* Compiler optimizations can remove arguments from static functions
6779 * or mismatched type can be passed into a global function.
6780 * In such cases mark the function as unreliable from BTF point of view.
6781 */
6782 if (err)
6783 prog->aux->func_info_aux[subprog].unreliable = true;
6784 return err;
6785}
6786
6787/* Compare BTF of a function call with given bpf_reg_state.
6788 * Returns:
6789 * EFAULT - there is a verifier bug. Abort verification.
6790 * EINVAL - there is a type mismatch or BTF is not available.
6791 * 0 - BTF matches with what bpf_reg_state expects.
6792 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
6793 *
6794 * NOTE: the code is duplicated from btf_check_subprog_arg_match()
6795 * because btf_check_func_arg_match() is still doing both. Once that
6796 * function is split in 2, we can call from here btf_check_subprog_arg_match()
6797 * first, and then treat the calling part in a new code path.
6798 */
6799int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
6800 struct bpf_reg_state *regs)
6801{
6802 struct bpf_prog *prog = env->prog;
6803 struct btf *btf = prog->aux->btf;
6804 bool is_global;
6805 u32 btf_id;
6806 int err;
6807
6808 if (!prog->aux->func_info)
6809 return -EINVAL;
6810
6811 btf_id = prog->aux->func_info[subprog].type_id;
6812 if (!btf_id)
6813 return -EFAULT;
6814
6815 if (prog->aux->func_info_aux[subprog].unreliable)
6816 return -EINVAL;
6817
6818 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
6819 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, true);
6820
6821 /* Compiler optimizations can remove arguments from static functions
6822 * or mismatched type can be passed into a global function.
6823 * In such cases mark the function as unreliable from BTF point of view.
6824 */
6825 if (err)
6826 prog->aux->func_info_aux[subprog].unreliable = true;
6827 return err;
6828}
6829
6830/* Convert BTF of a function into bpf_reg_state if possible
6831 * Returns:
6832 * EFAULT - there is a verifier bug. Abort verification.
6833 * EINVAL - cannot convert BTF.
6834 * 0 - Successfully converted BTF into bpf_reg_state
6835 * (either PTR_TO_CTX or SCALAR_VALUE).
6836 */
6837int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
6838 struct bpf_reg_state *regs)
6839{
6840 struct bpf_verifier_log *log = &env->log;
6841 struct bpf_prog *prog = env->prog;
6842 enum bpf_prog_type prog_type = prog->type;
6843 struct btf *btf = prog->aux->btf;
6844 const struct btf_param *args;
6845 const struct btf_type *t, *ref_t;
6846 u32 i, nargs, btf_id;
6847 const char *tname;
6848
6849 if (!prog->aux->func_info ||
6850 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
6851 bpf_log(log, "Verifier bug\n");
6852 return -EFAULT;
6853 }
6854
6855 btf_id = prog->aux->func_info[subprog].type_id;
6856 if (!btf_id) {
6857 bpf_log(log, "Global functions need valid BTF\n");
6858 return -EFAULT;
6859 }
6860
6861 t = btf_type_by_id(btf, btf_id);
6862 if (!t || !btf_type_is_func(t)) {
6863 /* These checks were already done by the verifier while loading
6864 * struct bpf_func_info
6865 */
6866 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
6867 subprog);
6868 return -EFAULT;
6869 }
6870 tname = btf_name_by_offset(btf, t->name_off);
6871
6872 if (log->level & BPF_LOG_LEVEL)
6873 bpf_log(log, "Validating %s() func#%d...\n",
6874 tname, subprog);
6875
6876 if (prog->aux->func_info_aux[subprog].unreliable) {
6877 bpf_log(log, "Verifier bug in function %s()\n", tname);
6878 return -EFAULT;
6879 }
6880 if (prog_type == BPF_PROG_TYPE_EXT)
6881 prog_type = prog->aux->dst_prog->type;
6882
6883 t = btf_type_by_id(btf, t->type);
6884 if (!t || !btf_type_is_func_proto(t)) {
6885 bpf_log(log, "Invalid type of function %s()\n", tname);
6886 return -EFAULT;
6887 }
6888 args = (const struct btf_param *)(t + 1);
6889 nargs = btf_type_vlen(t);
6890 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6891 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
6892 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
6893 return -EINVAL;
6894 }
6895 /* check that function returns int */
6896 t = btf_type_by_id(btf, t->type);
6897 while (btf_type_is_modifier(t))
6898 t = btf_type_by_id(btf, t->type);
6899 if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
6900 bpf_log(log,
6901 "Global function %s() doesn't return scalar. Only those are supported.\n",
6902 tname);
6903 return -EINVAL;
6904 }
6905 /* Convert BTF function arguments into verifier types.
6906 * Only PTR_TO_CTX and SCALAR are supported atm.
6907 */
6908 for (i = 0; i < nargs; i++) {
6909 struct bpf_reg_state *reg = ®s[i + 1];
6910
6911 t = btf_type_by_id(btf, args[i].type);
6912 while (btf_type_is_modifier(t))
6913 t = btf_type_by_id(btf, t->type);
6914 if (btf_type_is_int(t) || btf_is_any_enum(t)) {
6915 reg->type = SCALAR_VALUE;
6916 continue;
6917 }
6918 if (btf_type_is_ptr(t)) {
6919 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
6920 reg->type = PTR_TO_CTX;
6921 continue;
6922 }
6923
6924 t = btf_type_skip_modifiers(btf, t->type, NULL);
6925
6926 ref_t = btf_resolve_size(btf, t, ®->mem_size);
6927 if (IS_ERR(ref_t)) {
6928 bpf_log(log,
6929 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6930 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
6931 PTR_ERR(ref_t));
6932 return -EINVAL;
6933 }
6934
6935 reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
6936 reg->id = ++env->id_gen;
6937
6938 continue;
6939 }
6940 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
6941 i, btf_type_str(t), tname);
6942 return -EINVAL;
6943 }
6944 return 0;
6945}
6946
6947static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
6948 struct btf_show *show)
6949{
6950 const struct btf_type *t = btf_type_by_id(btf, type_id);
6951
6952 show->btf = btf;
6953 memset(&show->state, 0, sizeof(show->state));
6954 memset(&show->obj, 0, sizeof(show->obj));
6955
6956 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
6957}
6958
6959static void btf_seq_show(struct btf_show *show, const char *fmt,
6960 va_list args)
6961{
6962 seq_vprintf((struct seq_file *)show->target, fmt, args);
6963}
6964
6965int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
6966 void *obj, struct seq_file *m, u64 flags)
6967{
6968 struct btf_show sseq;
6969
6970 sseq.target = m;
6971 sseq.showfn = btf_seq_show;
6972 sseq.flags = flags;
6973
6974 btf_type_show(btf, type_id, obj, &sseq);
6975
6976 return sseq.state.status;
6977}
6978
6979void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
6980 struct seq_file *m)
6981{
6982 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
6983 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
6984 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
6985}
6986
6987struct btf_show_snprintf {
6988 struct btf_show show;
6989 int len_left; /* space left in string */
6990 int len; /* length we would have written */
6991};
6992
6993static void btf_snprintf_show(struct btf_show *show, const char *fmt,
6994 va_list args)
6995{
6996 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
6997 int len;
6998
6999 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
7000
7001 if (len < 0) {
7002 ssnprintf->len_left = 0;
7003 ssnprintf->len = len;
7004 } else if (len >= ssnprintf->len_left) {
7005 /* no space, drive on to get length we would have written */
7006 ssnprintf->len_left = 0;
7007 ssnprintf->len += len;
7008 } else {
7009 ssnprintf->len_left -= len;
7010 ssnprintf->len += len;
7011 show->target += len;
7012 }
7013}
7014
7015int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
7016 char *buf, int len, u64 flags)
7017{
7018 struct btf_show_snprintf ssnprintf;
7019
7020 ssnprintf.show.target = buf;
7021 ssnprintf.show.flags = flags;
7022 ssnprintf.show.showfn = btf_snprintf_show;
7023 ssnprintf.len_left = len;
7024 ssnprintf.len = 0;
7025
7026 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
7027
7028 /* If we encountered an error, return it. */
7029 if (ssnprintf.show.state.status)
7030 return ssnprintf.show.state.status;
7031
7032 /* Otherwise return length we would have written */
7033 return ssnprintf.len;
7034}
7035
7036#ifdef CONFIG_PROC_FS
7037static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
7038{
7039 const struct btf *btf = filp->private_data;
7040
7041 seq_printf(m, "btf_id:\t%u\n", btf->id);
7042}
7043#endif
7044
7045static int btf_release(struct inode *inode, struct file *filp)
7046{
7047 btf_put(filp->private_data);
7048 return 0;
7049}
7050
7051const struct file_operations btf_fops = {
7052#ifdef CONFIG_PROC_FS
7053 .show_fdinfo = bpf_btf_show_fdinfo,
7054#endif
7055 .release = btf_release,
7056};
7057
7058static int __btf_new_fd(struct btf *btf)
7059{
7060 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
7061}
7062
7063int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
7064{
7065 struct btf *btf;
7066 int ret;
7067
7068 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
7069 attr->btf_size, attr->btf_log_level,
7070 u64_to_user_ptr(attr->btf_log_buf),
7071 attr->btf_log_size);
7072 if (IS_ERR(btf))
7073 return PTR_ERR(btf);
7074
7075 ret = btf_alloc_id(btf);
7076 if (ret) {
7077 btf_free(btf);
7078 return ret;
7079 }
7080
7081 /*
7082 * The BTF ID is published to the userspace.
7083 * All BTF free must go through call_rcu() from
7084 * now on (i.e. free by calling btf_put()).
7085 */
7086
7087 ret = __btf_new_fd(btf);
7088 if (ret < 0)
7089 btf_put(btf);
7090
7091 return ret;
7092}
7093
7094struct btf *btf_get_by_fd(int fd)
7095{
7096 struct btf *btf;
7097 struct fd f;
7098
7099 f = fdget(fd);
7100
7101 if (!f.file)
7102 return ERR_PTR(-EBADF);
7103
7104 if (f.file->f_op != &btf_fops) {
7105 fdput(f);
7106 return ERR_PTR(-EINVAL);
7107 }
7108
7109 btf = f.file->private_data;
7110 refcount_inc(&btf->refcnt);
7111 fdput(f);
7112
7113 return btf;
7114}
7115
7116int btf_get_info_by_fd(const struct btf *btf,
7117 const union bpf_attr *attr,
7118 union bpf_attr __user *uattr)
7119{
7120 struct bpf_btf_info __user *uinfo;
7121 struct bpf_btf_info info;
7122 u32 info_copy, btf_copy;
7123 void __user *ubtf;
7124 char __user *uname;
7125 u32 uinfo_len, uname_len, name_len;
7126 int ret = 0;
7127
7128 uinfo = u64_to_user_ptr(attr->info.info);
7129 uinfo_len = attr->info.info_len;
7130
7131 info_copy = min_t(u32, uinfo_len, sizeof(info));
7132 memset(&info, 0, sizeof(info));
7133 if (copy_from_user(&info, uinfo, info_copy))
7134 return -EFAULT;
7135
7136 info.id = btf->id;
7137 ubtf = u64_to_user_ptr(info.btf);
7138 btf_copy = min_t(u32, btf->data_size, info.btf_size);
7139 if (copy_to_user(ubtf, btf->data, btf_copy))
7140 return -EFAULT;
7141 info.btf_size = btf->data_size;
7142
7143 info.kernel_btf = btf->kernel_btf;
7144
7145 uname = u64_to_user_ptr(info.name);
7146 uname_len = info.name_len;
7147 if (!uname ^ !uname_len)
7148 return -EINVAL;
7149
7150 name_len = strlen(btf->name);
7151 info.name_len = name_len;
7152
7153 if (uname) {
7154 if (uname_len >= name_len + 1) {
7155 if (copy_to_user(uname, btf->name, name_len + 1))
7156 return -EFAULT;
7157 } else {
7158 char zero = '\0';
7159
7160 if (copy_to_user(uname, btf->name, uname_len - 1))
7161 return -EFAULT;
7162 if (put_user(zero, uname + uname_len - 1))
7163 return -EFAULT;
7164 /* let user-space know about too short buffer */
7165 ret = -ENOSPC;
7166 }
7167 }
7168
7169 if (copy_to_user(uinfo, &info, info_copy) ||
7170 put_user(info_copy, &uattr->info.info_len))
7171 return -EFAULT;
7172
7173 return ret;
7174}
7175
7176int btf_get_fd_by_id(u32 id)
7177{
7178 struct btf *btf;
7179 int fd;
7180
7181 rcu_read_lock();
7182 btf = idr_find(&btf_idr, id);
7183 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
7184 btf = ERR_PTR(-ENOENT);
7185 rcu_read_unlock();
7186
7187 if (IS_ERR(btf))
7188 return PTR_ERR(btf);
7189
7190 fd = __btf_new_fd(btf);
7191 if (fd < 0)
7192 btf_put(btf);
7193
7194 return fd;
7195}
7196
7197u32 btf_obj_id(const struct btf *btf)
7198{
7199 return btf->id;
7200}
7201
7202bool btf_is_kernel(const struct btf *btf)
7203{
7204 return btf->kernel_btf;
7205}
7206
7207bool btf_is_module(const struct btf *btf)
7208{
7209 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
7210}
7211
7212enum {
7213 BTF_MODULE_F_LIVE = (1 << 0),
7214};
7215
7216#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7217struct btf_module {
7218 struct list_head list;
7219 struct module *module;
7220 struct btf *btf;
7221 struct bin_attribute *sysfs_attr;
7222 int flags;
7223};
7224
7225static LIST_HEAD(btf_modules);
7226static DEFINE_MUTEX(btf_module_mutex);
7227
7228static ssize_t
7229btf_module_read(struct file *file, struct kobject *kobj,
7230 struct bin_attribute *bin_attr,
7231 char *buf, loff_t off, size_t len)
7232{
7233 const struct btf *btf = bin_attr->private;
7234
7235 memcpy(buf, btf->data + off, len);
7236 return len;
7237}
7238
7239static void purge_cand_cache(struct btf *btf);
7240
7241static int btf_module_notify(struct notifier_block *nb, unsigned long op,
7242 void *module)
7243{
7244 struct btf_module *btf_mod, *tmp;
7245 struct module *mod = module;
7246 struct btf *btf;
7247 int err = 0;
7248
7249 if (mod->btf_data_size == 0 ||
7250 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
7251 op != MODULE_STATE_GOING))
7252 goto out;
7253
7254 switch (op) {
7255 case MODULE_STATE_COMING:
7256 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
7257 if (!btf_mod) {
7258 err = -ENOMEM;
7259 goto out;
7260 }
7261 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
7262 if (IS_ERR(btf)) {
7263 pr_warn("failed to validate module [%s] BTF: %ld\n",
7264 mod->name, PTR_ERR(btf));
7265 kfree(btf_mod);
7266 if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
7267 err = PTR_ERR(btf);
7268 goto out;
7269 }
7270 err = btf_alloc_id(btf);
7271 if (err) {
7272 btf_free(btf);
7273 kfree(btf_mod);
7274 goto out;
7275 }
7276
7277 purge_cand_cache(NULL);
7278 mutex_lock(&btf_module_mutex);
7279 btf_mod->module = module;
7280 btf_mod->btf = btf;
7281 list_add(&btf_mod->list, &btf_modules);
7282 mutex_unlock(&btf_module_mutex);
7283
7284 if (IS_ENABLED(CONFIG_SYSFS)) {
7285 struct bin_attribute *attr;
7286
7287 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
7288 if (!attr)
7289 goto out;
7290
7291 sysfs_bin_attr_init(attr);
7292 attr->attr.name = btf->name;
7293 attr->attr.mode = 0444;
7294 attr->size = btf->data_size;
7295 attr->private = btf;
7296 attr->read = btf_module_read;
7297
7298 err = sysfs_create_bin_file(btf_kobj, attr);
7299 if (err) {
7300 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
7301 mod->name, err);
7302 kfree(attr);
7303 err = 0;
7304 goto out;
7305 }
7306
7307 btf_mod->sysfs_attr = attr;
7308 }
7309
7310 break;
7311 case MODULE_STATE_LIVE:
7312 mutex_lock(&btf_module_mutex);
7313 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7314 if (btf_mod->module != module)
7315 continue;
7316
7317 btf_mod->flags |= BTF_MODULE_F_LIVE;
7318 break;
7319 }
7320 mutex_unlock(&btf_module_mutex);
7321 break;
7322 case MODULE_STATE_GOING:
7323 mutex_lock(&btf_module_mutex);
7324 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7325 if (btf_mod->module != module)
7326 continue;
7327
7328 list_del(&btf_mod->list);
7329 if (btf_mod->sysfs_attr)
7330 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
7331 purge_cand_cache(btf_mod->btf);
7332 btf_put(btf_mod->btf);
7333 kfree(btf_mod->sysfs_attr);
7334 kfree(btf_mod);
7335 break;
7336 }
7337 mutex_unlock(&btf_module_mutex);
7338 break;
7339 }
7340out:
7341 return notifier_from_errno(err);
7342}
7343
7344static struct notifier_block btf_module_nb = {
7345 .notifier_call = btf_module_notify,
7346};
7347
7348static int __init btf_module_init(void)
7349{
7350 register_module_notifier(&btf_module_nb);
7351 return 0;
7352}
7353
7354fs_initcall(btf_module_init);
7355#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
7356
7357struct module *btf_try_get_module(const struct btf *btf)
7358{
7359 struct module *res = NULL;
7360#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7361 struct btf_module *btf_mod, *tmp;
7362
7363 mutex_lock(&btf_module_mutex);
7364 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7365 if (btf_mod->btf != btf)
7366 continue;
7367
7368 /* We must only consider module whose __init routine has
7369 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
7370 * which is set from the notifier callback for
7371 * MODULE_STATE_LIVE.
7372 */
7373 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
7374 res = btf_mod->module;
7375
7376 break;
7377 }
7378 mutex_unlock(&btf_module_mutex);
7379#endif
7380
7381 return res;
7382}
7383
7384/* Returns struct btf corresponding to the struct module.
7385 * This function can return NULL or ERR_PTR.
7386 */
7387static struct btf *btf_get_module_btf(const struct module *module)
7388{
7389#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7390 struct btf_module *btf_mod, *tmp;
7391#endif
7392 struct btf *btf = NULL;
7393
7394 if (!module) {
7395 btf = bpf_get_btf_vmlinux();
7396 if (!IS_ERR_OR_NULL(btf))
7397 btf_get(btf);
7398 return btf;
7399 }
7400
7401#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7402 mutex_lock(&btf_module_mutex);
7403 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7404 if (btf_mod->module != module)
7405 continue;
7406
7407 btf_get(btf_mod->btf);
7408 btf = btf_mod->btf;
7409 break;
7410 }
7411 mutex_unlock(&btf_module_mutex);
7412#endif
7413
7414 return btf;
7415}
7416
7417BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
7418{
7419 struct btf *btf = NULL;
7420 int btf_obj_fd = 0;
7421 long ret;
7422
7423 if (flags)
7424 return -EINVAL;
7425
7426 if (name_sz <= 1 || name[name_sz - 1])
7427 return -EINVAL;
7428
7429 ret = bpf_find_btf_id(name, kind, &btf);
7430 if (ret > 0 && btf_is_module(btf)) {
7431 btf_obj_fd = __btf_new_fd(btf);
7432 if (btf_obj_fd < 0) {
7433 btf_put(btf);
7434 return btf_obj_fd;
7435 }
7436 return ret | (((u64)btf_obj_fd) << 32);
7437 }
7438 if (ret > 0)
7439 btf_put(btf);
7440 return ret;
7441}
7442
7443const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
7444 .func = bpf_btf_find_by_name_kind,
7445 .gpl_only = false,
7446 .ret_type = RET_INTEGER,
7447 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
7448 .arg2_type = ARG_CONST_SIZE,
7449 .arg3_type = ARG_ANYTHING,
7450 .arg4_type = ARG_ANYTHING,
7451};
7452
7453BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
7454#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
7455BTF_TRACING_TYPE_xxx
7456#undef BTF_TRACING_TYPE
7457
7458/* Kernel Function (kfunc) BTF ID set registration API */
7459
7460static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
7461 struct btf_id_set8 *add_set)
7462{
7463 bool vmlinux_set = !btf_is_module(btf);
7464 struct btf_kfunc_set_tab *tab;
7465 struct btf_id_set8 *set;
7466 u32 set_cnt;
7467 int ret;
7468
7469 if (hook >= BTF_KFUNC_HOOK_MAX) {
7470 ret = -EINVAL;
7471 goto end;
7472 }
7473
7474 if (!add_set->cnt)
7475 return 0;
7476
7477 tab = btf->kfunc_set_tab;
7478 if (!tab) {
7479 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
7480 if (!tab)
7481 return -ENOMEM;
7482 btf->kfunc_set_tab = tab;
7483 }
7484
7485 set = tab->sets[hook];
7486 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
7487 * for module sets.
7488 */
7489 if (WARN_ON_ONCE(set && !vmlinux_set)) {
7490 ret = -EINVAL;
7491 goto end;
7492 }
7493
7494 /* We don't need to allocate, concatenate, and sort module sets, because
7495 * only one is allowed per hook. Hence, we can directly assign the
7496 * pointer and return.
7497 */
7498 if (!vmlinux_set) {
7499 tab->sets[hook] = add_set;
7500 return 0;
7501 }
7502
7503 /* In case of vmlinux sets, there may be more than one set being
7504 * registered per hook. To create a unified set, we allocate a new set
7505 * and concatenate all individual sets being registered. While each set
7506 * is individually sorted, they may become unsorted when concatenated,
7507 * hence re-sorting the final set again is required to make binary
7508 * searching the set using btf_id_set8_contains function work.
7509 */
7510 set_cnt = set ? set->cnt : 0;
7511
7512 if (set_cnt > U32_MAX - add_set->cnt) {
7513 ret = -EOVERFLOW;
7514 goto end;
7515 }
7516
7517 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
7518 ret = -E2BIG;
7519 goto end;
7520 }
7521
7522 /* Grow set */
7523 set = krealloc(tab->sets[hook],
7524 offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
7525 GFP_KERNEL | __GFP_NOWARN);
7526 if (!set) {
7527 ret = -ENOMEM;
7528 goto end;
7529 }
7530
7531 /* For newly allocated set, initialize set->cnt to 0 */
7532 if (!tab->sets[hook])
7533 set->cnt = 0;
7534 tab->sets[hook] = set;
7535
7536 /* Concatenate the two sets */
7537 memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
7538 set->cnt += add_set->cnt;
7539
7540 sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
7541
7542 return 0;
7543end:
7544 btf_free_kfunc_set_tab(btf);
7545 return ret;
7546}
7547
7548static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
7549 enum btf_kfunc_hook hook,
7550 u32 kfunc_btf_id)
7551{
7552 struct btf_id_set8 *set;
7553 u32 *id;
7554
7555 if (hook >= BTF_KFUNC_HOOK_MAX)
7556 return NULL;
7557 if (!btf->kfunc_set_tab)
7558 return NULL;
7559 set = btf->kfunc_set_tab->sets[hook];
7560 if (!set)
7561 return NULL;
7562 id = btf_id_set8_contains(set, kfunc_btf_id);
7563 if (!id)
7564 return NULL;
7565 /* The flags for BTF ID are located next to it */
7566 return id + 1;
7567}
7568
7569static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
7570{
7571 switch (prog_type) {
7572 case BPF_PROG_TYPE_UNSPEC:
7573 return BTF_KFUNC_HOOK_COMMON;
7574 case BPF_PROG_TYPE_XDP:
7575 return BTF_KFUNC_HOOK_XDP;
7576 case BPF_PROG_TYPE_SCHED_CLS:
7577 return BTF_KFUNC_HOOK_TC;
7578 case BPF_PROG_TYPE_STRUCT_OPS:
7579 return BTF_KFUNC_HOOK_STRUCT_OPS;
7580 case BPF_PROG_TYPE_TRACING:
7581 case BPF_PROG_TYPE_LSM:
7582 return BTF_KFUNC_HOOK_TRACING;
7583 case BPF_PROG_TYPE_SYSCALL:
7584 return BTF_KFUNC_HOOK_SYSCALL;
7585 default:
7586 return BTF_KFUNC_HOOK_MAX;
7587 }
7588}
7589
7590/* Caution:
7591 * Reference to the module (obtained using btf_try_get_module) corresponding to
7592 * the struct btf *MUST* be held when calling this function from verifier
7593 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
7594 * keeping the reference for the duration of the call provides the necessary
7595 * protection for looking up a well-formed btf->kfunc_set_tab.
7596 */
7597u32 *btf_kfunc_id_set_contains(const struct btf *btf,
7598 enum bpf_prog_type prog_type,
7599 u32 kfunc_btf_id)
7600{
7601 enum btf_kfunc_hook hook;
7602 u32 *kfunc_flags;
7603
7604 kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id);
7605 if (kfunc_flags)
7606 return kfunc_flags;
7607
7608 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7609 return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id);
7610}
7611
7612u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id)
7613{
7614 return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id);
7615}
7616
7617static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
7618 const struct btf_kfunc_id_set *kset)
7619{
7620 struct btf *btf;
7621 int ret;
7622
7623 btf = btf_get_module_btf(kset->owner);
7624 if (!btf) {
7625 if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7626 pr_err("missing vmlinux BTF, cannot register kfuncs\n");
7627 return -ENOENT;
7628 }
7629 if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
7630 pr_err("missing module BTF, cannot register kfuncs\n");
7631 return -ENOENT;
7632 }
7633 return 0;
7634 }
7635 if (IS_ERR(btf))
7636 return PTR_ERR(btf);
7637
7638 ret = btf_populate_kfunc_set(btf, hook, kset->set);
7639 btf_put(btf);
7640 return ret;
7641}
7642
7643/* This function must be invoked only from initcalls/module init functions */
7644int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
7645 const struct btf_kfunc_id_set *kset)
7646{
7647 enum btf_kfunc_hook hook;
7648
7649 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7650 return __register_btf_kfunc_id_set(hook, kset);
7651}
7652EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
7653
7654/* This function must be invoked only from initcalls/module init functions */
7655int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset)
7656{
7657 return __register_btf_kfunc_id_set(BTF_KFUNC_HOOK_FMODRET, kset);
7658}
7659EXPORT_SYMBOL_GPL(register_btf_fmodret_id_set);
7660
7661s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
7662{
7663 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
7664 struct btf_id_dtor_kfunc *dtor;
7665
7666 if (!tab)
7667 return -ENOENT;
7668 /* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
7669 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
7670 */
7671 BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
7672 dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
7673 if (!dtor)
7674 return -ENOENT;
7675 return dtor->kfunc_btf_id;
7676}
7677
7678static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
7679{
7680 const struct btf_type *dtor_func, *dtor_func_proto, *t;
7681 const struct btf_param *args;
7682 s32 dtor_btf_id;
7683 u32 nr_args, i;
7684
7685 for (i = 0; i < cnt; i++) {
7686 dtor_btf_id = dtors[i].kfunc_btf_id;
7687
7688 dtor_func = btf_type_by_id(btf, dtor_btf_id);
7689 if (!dtor_func || !btf_type_is_func(dtor_func))
7690 return -EINVAL;
7691
7692 dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
7693 if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
7694 return -EINVAL;
7695
7696 /* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
7697 t = btf_type_by_id(btf, dtor_func_proto->type);
7698 if (!t || !btf_type_is_void(t))
7699 return -EINVAL;
7700
7701 nr_args = btf_type_vlen(dtor_func_proto);
7702 if (nr_args != 1)
7703 return -EINVAL;
7704 args = btf_params(dtor_func_proto);
7705 t = btf_type_by_id(btf, args[0].type);
7706 /* Allow any pointer type, as width on targets Linux supports
7707 * will be same for all pointer types (i.e. sizeof(void *))
7708 */
7709 if (!t || !btf_type_is_ptr(t))
7710 return -EINVAL;
7711 }
7712 return 0;
7713}
7714
7715/* This function must be invoked only from initcalls/module init functions */
7716int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
7717 struct module *owner)
7718{
7719 struct btf_id_dtor_kfunc_tab *tab;
7720 struct btf *btf;
7721 u32 tab_cnt;
7722 int ret;
7723
7724 btf = btf_get_module_btf(owner);
7725 if (!btf) {
7726 if (!owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7727 pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n");
7728 return -ENOENT;
7729 }
7730 if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
7731 pr_err("missing module BTF, cannot register dtor kfuncs\n");
7732 return -ENOENT;
7733 }
7734 return 0;
7735 }
7736 if (IS_ERR(btf))
7737 return PTR_ERR(btf);
7738
7739 if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
7740 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
7741 ret = -E2BIG;
7742 goto end;
7743 }
7744
7745 /* Ensure that the prototype of dtor kfuncs being registered is sane */
7746 ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
7747 if (ret < 0)
7748 goto end;
7749
7750 tab = btf->dtor_kfunc_tab;
7751 /* Only one call allowed for modules */
7752 if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
7753 ret = -EINVAL;
7754 goto end;
7755 }
7756
7757 tab_cnt = tab ? tab->cnt : 0;
7758 if (tab_cnt > U32_MAX - add_cnt) {
7759 ret = -EOVERFLOW;
7760 goto end;
7761 }
7762 if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
7763 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
7764 ret = -E2BIG;
7765 goto end;
7766 }
7767
7768 tab = krealloc(btf->dtor_kfunc_tab,
7769 offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
7770 GFP_KERNEL | __GFP_NOWARN);
7771 if (!tab) {
7772 ret = -ENOMEM;
7773 goto end;
7774 }
7775
7776 if (!btf->dtor_kfunc_tab)
7777 tab->cnt = 0;
7778 btf->dtor_kfunc_tab = tab;
7779
7780 memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
7781 tab->cnt += add_cnt;
7782
7783 sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
7784
7785end:
7786 if (ret)
7787 btf_free_dtor_kfunc_tab(btf);
7788 btf_put(btf);
7789 return ret;
7790}
7791EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
7792
7793#define MAX_TYPES_ARE_COMPAT_DEPTH 2
7794
7795/* Check local and target types for compatibility. This check is used for
7796 * type-based CO-RE relocations and follow slightly different rules than
7797 * field-based relocations. This function assumes that root types were already
7798 * checked for name match. Beyond that initial root-level name check, names
7799 * are completely ignored. Compatibility rules are as follows:
7800 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
7801 * kind should match for local and target types (i.e., STRUCT is not
7802 * compatible with UNION);
7803 * - for ENUMs/ENUM64s, the size is ignored;
7804 * - for INT, size and signedness are ignored;
7805 * - for ARRAY, dimensionality is ignored, element types are checked for
7806 * compatibility recursively;
7807 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
7808 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
7809 * - FUNC_PROTOs are compatible if they have compatible signature: same
7810 * number of input args and compatible return and argument types.
7811 * These rules are not set in stone and probably will be adjusted as we get
7812 * more experience with using BPF CO-RE relocations.
7813 */
7814int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
7815 const struct btf *targ_btf, __u32 targ_id)
7816{
7817 return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
7818 MAX_TYPES_ARE_COMPAT_DEPTH);
7819}
7820
7821#define MAX_TYPES_MATCH_DEPTH 2
7822
7823int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
7824 const struct btf *targ_btf, u32 targ_id)
7825{
7826 return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
7827 MAX_TYPES_MATCH_DEPTH);
7828}
7829
7830static bool bpf_core_is_flavor_sep(const char *s)
7831{
7832 /* check X___Y name pattern, where X and Y are not underscores */
7833 return s[0] != '_' && /* X */
7834 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
7835 s[4] != '_'; /* Y */
7836}
7837
7838size_t bpf_core_essential_name_len(const char *name)
7839{
7840 size_t n = strlen(name);
7841 int i;
7842
7843 for (i = n - 5; i >= 0; i--) {
7844 if (bpf_core_is_flavor_sep(name + i))
7845 return i + 1;
7846 }
7847 return n;
7848}
7849
7850struct bpf_cand_cache {
7851 const char *name;
7852 u32 name_len;
7853 u16 kind;
7854 u16 cnt;
7855 struct {
7856 const struct btf *btf;
7857 u32 id;
7858 } cands[];
7859};
7860
7861static void bpf_free_cands(struct bpf_cand_cache *cands)
7862{
7863 if (!cands->cnt)
7864 /* empty candidate array was allocated on stack */
7865 return;
7866 kfree(cands);
7867}
7868
7869static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
7870{
7871 kfree(cands->name);
7872 kfree(cands);
7873}
7874
7875#define VMLINUX_CAND_CACHE_SIZE 31
7876static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
7877
7878#define MODULE_CAND_CACHE_SIZE 31
7879static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
7880
7881static DEFINE_MUTEX(cand_cache_mutex);
7882
7883static void __print_cand_cache(struct bpf_verifier_log *log,
7884 struct bpf_cand_cache **cache,
7885 int cache_size)
7886{
7887 struct bpf_cand_cache *cc;
7888 int i, j;
7889
7890 for (i = 0; i < cache_size; i++) {
7891 cc = cache[i];
7892 if (!cc)
7893 continue;
7894 bpf_log(log, "[%d]%s(", i, cc->name);
7895 for (j = 0; j < cc->cnt; j++) {
7896 bpf_log(log, "%d", cc->cands[j].id);
7897 if (j < cc->cnt - 1)
7898 bpf_log(log, " ");
7899 }
7900 bpf_log(log, "), ");
7901 }
7902}
7903
7904static void print_cand_cache(struct bpf_verifier_log *log)
7905{
7906 mutex_lock(&cand_cache_mutex);
7907 bpf_log(log, "vmlinux_cand_cache:");
7908 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7909 bpf_log(log, "\nmodule_cand_cache:");
7910 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7911 bpf_log(log, "\n");
7912 mutex_unlock(&cand_cache_mutex);
7913}
7914
7915static u32 hash_cands(struct bpf_cand_cache *cands)
7916{
7917 return jhash(cands->name, cands->name_len, 0);
7918}
7919
7920static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
7921 struct bpf_cand_cache **cache,
7922 int cache_size)
7923{
7924 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
7925
7926 if (cc && cc->name_len == cands->name_len &&
7927 !strncmp(cc->name, cands->name, cands->name_len))
7928 return cc;
7929 return NULL;
7930}
7931
7932static size_t sizeof_cands(int cnt)
7933{
7934 return offsetof(struct bpf_cand_cache, cands[cnt]);
7935}
7936
7937static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
7938 struct bpf_cand_cache **cache,
7939 int cache_size)
7940{
7941 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
7942
7943 if (*cc) {
7944 bpf_free_cands_from_cache(*cc);
7945 *cc = NULL;
7946 }
7947 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
7948 if (!new_cands) {
7949 bpf_free_cands(cands);
7950 return ERR_PTR(-ENOMEM);
7951 }
7952 /* strdup the name, since it will stay in cache.
7953 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
7954 */
7955 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
7956 bpf_free_cands(cands);
7957 if (!new_cands->name) {
7958 kfree(new_cands);
7959 return ERR_PTR(-ENOMEM);
7960 }
7961 *cc = new_cands;
7962 return new_cands;
7963}
7964
7965#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7966static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
7967 int cache_size)
7968{
7969 struct bpf_cand_cache *cc;
7970 int i, j;
7971
7972 for (i = 0; i < cache_size; i++) {
7973 cc = cache[i];
7974 if (!cc)
7975 continue;
7976 if (!btf) {
7977 /* when new module is loaded purge all of module_cand_cache,
7978 * since new module might have candidates with the name
7979 * that matches cached cands.
7980 */
7981 bpf_free_cands_from_cache(cc);
7982 cache[i] = NULL;
7983 continue;
7984 }
7985 /* when module is unloaded purge cache entries
7986 * that match module's btf
7987 */
7988 for (j = 0; j < cc->cnt; j++)
7989 if (cc->cands[j].btf == btf) {
7990 bpf_free_cands_from_cache(cc);
7991 cache[i] = NULL;
7992 break;
7993 }
7994 }
7995
7996}
7997
7998static void purge_cand_cache(struct btf *btf)
7999{
8000 mutex_lock(&cand_cache_mutex);
8001 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8002 mutex_unlock(&cand_cache_mutex);
8003}
8004#endif
8005
8006static struct bpf_cand_cache *
8007bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
8008 int targ_start_id)
8009{
8010 struct bpf_cand_cache *new_cands;
8011 const struct btf_type *t;
8012 const char *targ_name;
8013 size_t targ_essent_len;
8014 int n, i;
8015
8016 n = btf_nr_types(targ_btf);
8017 for (i = targ_start_id; i < n; i++) {
8018 t = btf_type_by_id(targ_btf, i);
8019 if (btf_kind(t) != cands->kind)
8020 continue;
8021
8022 targ_name = btf_name_by_offset(targ_btf, t->name_off);
8023 if (!targ_name)
8024 continue;
8025
8026 /* the resched point is before strncmp to make sure that search
8027 * for non-existing name will have a chance to schedule().
8028 */
8029 cond_resched();
8030
8031 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
8032 continue;
8033
8034 targ_essent_len = bpf_core_essential_name_len(targ_name);
8035 if (targ_essent_len != cands->name_len)
8036 continue;
8037
8038 /* most of the time there is only one candidate for a given kind+name pair */
8039 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
8040 if (!new_cands) {
8041 bpf_free_cands(cands);
8042 return ERR_PTR(-ENOMEM);
8043 }
8044
8045 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
8046 bpf_free_cands(cands);
8047 cands = new_cands;
8048 cands->cands[cands->cnt].btf = targ_btf;
8049 cands->cands[cands->cnt].id = i;
8050 cands->cnt++;
8051 }
8052 return cands;
8053}
8054
8055static struct bpf_cand_cache *
8056bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
8057{
8058 struct bpf_cand_cache *cands, *cc, local_cand = {};
8059 const struct btf *local_btf = ctx->btf;
8060 const struct btf_type *local_type;
8061 const struct btf *main_btf;
8062 size_t local_essent_len;
8063 struct btf *mod_btf;
8064 const char *name;
8065 int id;
8066
8067 main_btf = bpf_get_btf_vmlinux();
8068 if (IS_ERR(main_btf))
8069 return ERR_CAST(main_btf);
8070 if (!main_btf)
8071 return ERR_PTR(-EINVAL);
8072
8073 local_type = btf_type_by_id(local_btf, local_type_id);
8074 if (!local_type)
8075 return ERR_PTR(-EINVAL);
8076
8077 name = btf_name_by_offset(local_btf, local_type->name_off);
8078 if (str_is_empty(name))
8079 return ERR_PTR(-EINVAL);
8080 local_essent_len = bpf_core_essential_name_len(name);
8081
8082 cands = &local_cand;
8083 cands->name = name;
8084 cands->kind = btf_kind(local_type);
8085 cands->name_len = local_essent_len;
8086
8087 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8088 /* cands is a pointer to stack here */
8089 if (cc) {
8090 if (cc->cnt)
8091 return cc;
8092 goto check_modules;
8093 }
8094
8095 /* Attempt to find target candidates in vmlinux BTF first */
8096 cands = bpf_core_add_cands(cands, main_btf, 1);
8097 if (IS_ERR(cands))
8098 return ERR_CAST(cands);
8099
8100 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
8101
8102 /* populate cache even when cands->cnt == 0 */
8103 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8104 if (IS_ERR(cc))
8105 return ERR_CAST(cc);
8106
8107 /* if vmlinux BTF has any candidate, don't go for module BTFs */
8108 if (cc->cnt)
8109 return cc;
8110
8111check_modules:
8112 /* cands is a pointer to stack here and cands->cnt == 0 */
8113 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8114 if (cc)
8115 /* if cache has it return it even if cc->cnt == 0 */
8116 return cc;
8117
8118 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
8119 spin_lock_bh(&btf_idr_lock);
8120 idr_for_each_entry(&btf_idr, mod_btf, id) {
8121 if (!btf_is_module(mod_btf))
8122 continue;
8123 /* linear search could be slow hence unlock/lock
8124 * the IDR to avoiding holding it for too long
8125 */
8126 btf_get(mod_btf);
8127 spin_unlock_bh(&btf_idr_lock);
8128 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
8129 if (IS_ERR(cands)) {
8130 btf_put(mod_btf);
8131 return ERR_CAST(cands);
8132 }
8133 spin_lock_bh(&btf_idr_lock);
8134 btf_put(mod_btf);
8135 }
8136 spin_unlock_bh(&btf_idr_lock);
8137 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
8138 * or pointer to stack if cands->cnd == 0.
8139 * Copy it into the cache even when cands->cnt == 0 and
8140 * return the result.
8141 */
8142 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8143}
8144
8145int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
8146 int relo_idx, void *insn)
8147{
8148 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
8149 struct bpf_core_cand_list cands = {};
8150 struct bpf_core_relo_res targ_res;
8151 struct bpf_core_spec *specs;
8152 int err;
8153
8154 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
8155 * into arrays of btf_ids of struct fields and array indices.
8156 */
8157 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
8158 if (!specs)
8159 return -ENOMEM;
8160
8161 if (need_cands) {
8162 struct bpf_cand_cache *cc;
8163 int i;
8164
8165 mutex_lock(&cand_cache_mutex);
8166 cc = bpf_core_find_cands(ctx, relo->type_id);
8167 if (IS_ERR(cc)) {
8168 bpf_log(ctx->log, "target candidate search failed for %d\n",
8169 relo->type_id);
8170 err = PTR_ERR(cc);
8171 goto out;
8172 }
8173 if (cc->cnt) {
8174 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
8175 if (!cands.cands) {
8176 err = -ENOMEM;
8177 goto out;
8178 }
8179 }
8180 for (i = 0; i < cc->cnt; i++) {
8181 bpf_log(ctx->log,
8182 "CO-RE relocating %s %s: found target candidate [%d]\n",
8183 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
8184 cands.cands[i].btf = cc->cands[i].btf;
8185 cands.cands[i].id = cc->cands[i].id;
8186 }
8187 cands.len = cc->cnt;
8188 /* cand_cache_mutex needs to span the cache lookup and
8189 * copy of btf pointer into bpf_core_cand_list,
8190 * since module can be unloaded while bpf_core_calc_relo_insn
8191 * is working with module's btf.
8192 */
8193 }
8194
8195 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
8196 &targ_res);
8197 if (err)
8198 goto out;
8199
8200 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
8201 &targ_res);
8202
8203out:
8204 kfree(specs);
8205 if (need_cands) {
8206 kfree(cands.cands);
8207 mutex_unlock(&cand_cache_mutex);
8208 if (ctx->log->level & BPF_LOG_LEVEL2)
8209 print_cand_cache(ctx->log);
8210 }
8211 return err;
8212}
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}