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1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2018 Facebook */
3
4#include <uapi/linux/btf.h>
5#include <uapi/linux/bpf.h>
6#include <uapi/linux/bpf_perf_event.h>
7#include <uapi/linux/types.h>
8#include <linux/seq_file.h>
9#include <linux/compiler.h>
10#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/slab.h>
13#include <linux/anon_inodes.h>
14#include <linux/file.h>
15#include <linux/uaccess.h>
16#include <linux/kernel.h>
17#include <linux/idr.h>
18#include <linux/sort.h>
19#include <linux/bpf_verifier.h>
20#include <linux/btf.h>
21#include <linux/btf_ids.h>
22#include <linux/bpf_lsm.h>
23#include <linux/skmsg.h>
24#include <linux/perf_event.h>
25#include <linux/bsearch.h>
26#include <linux/kobject.h>
27#include <linux/sysfs.h>
28#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/skmsg.h>
23#include <linux/perf_event.h>
24#include <linux/bsearch.h>
25#include <linux/kobject.h>
26#include <linux/sysfs.h>
27#include <net/sock.h>
28
29/* BTF (BPF Type Format) is the meta data format which describes
30 * the data types of BPF program/map. Hence, it basically focus
31 * on the C programming language which the modern BPF is primary
32 * using.
33 *
34 * ELF Section:
35 * ~~~~~~~~~~~
36 * The BTF data is stored under the ".BTF" ELF section
37 *
38 * struct btf_type:
39 * ~~~~~~~~~~~~~~~
40 * Each 'struct btf_type' object describes a C data type.
41 * Depending on the type it is describing, a 'struct btf_type'
42 * object may be followed by more data. F.e.
43 * To describe an array, 'struct btf_type' is followed by
44 * 'struct btf_array'.
45 *
46 * 'struct btf_type' and any extra data following it are
47 * 4 bytes aligned.
48 *
49 * Type section:
50 * ~~~~~~~~~~~~~
51 * The BTF type section contains a list of 'struct btf_type' objects.
52 * Each one describes a C type. Recall from the above section
53 * that a 'struct btf_type' object could be immediately followed by extra
54 * data in order to describe some particular C types.
55 *
56 * type_id:
57 * ~~~~~~~
58 * Each btf_type object is identified by a type_id. The type_id
59 * is implicitly implied by the location of the btf_type object in
60 * the BTF type section. The first one has type_id 1. The second
61 * one has type_id 2...etc. Hence, an earlier btf_type has
62 * a smaller type_id.
63 *
64 * A btf_type object may refer to another btf_type object by using
65 * type_id (i.e. the "type" in the "struct btf_type").
66 *
67 * NOTE that we cannot assume any reference-order.
68 * A btf_type object can refer to an earlier btf_type object
69 * but it can also refer to a later btf_type object.
70 *
71 * For example, to describe "const void *". A btf_type
72 * object describing "const" may refer to another btf_type
73 * object describing "void *". This type-reference is done
74 * by specifying type_id:
75 *
76 * [1] CONST (anon) type_id=2
77 * [2] PTR (anon) type_id=0
78 *
79 * The above is the btf_verifier debug log:
80 * - Each line started with "[?]" is a btf_type object
81 * - [?] is the type_id of the btf_type object.
82 * - CONST/PTR is the BTF_KIND_XXX
83 * - "(anon)" is the name of the type. It just
84 * happens that CONST and PTR has no name.
85 * - type_id=XXX is the 'u32 type' in btf_type
86 *
87 * NOTE: "void" has type_id 0
88 *
89 * String section:
90 * ~~~~~~~~~~~~~~
91 * The BTF string section contains the names used by the type section.
92 * Each string is referred by an "offset" from the beginning of the
93 * string section.
94 *
95 * Each string is '\0' terminated.
96 *
97 * The first character in the string section must be '\0'
98 * which is used to mean 'anonymous'. Some btf_type may not
99 * have a name.
100 */
101
102/* BTF verification:
103 *
104 * To verify BTF data, two passes are needed.
105 *
106 * Pass #1
107 * ~~~~~~~
108 * The first pass is to collect all btf_type objects to
109 * an array: "btf->types".
110 *
111 * Depending on the C type that a btf_type is describing,
112 * a btf_type may be followed by extra data. We don't know
113 * how many btf_type is there, and more importantly we don't
114 * know where each btf_type is located in the type section.
115 *
116 * Without knowing the location of each type_id, most verifications
117 * cannot be done. e.g. an earlier btf_type may refer to a later
118 * btf_type (recall the "const void *" above), so we cannot
119 * check this type-reference in the first pass.
120 *
121 * In the first pass, it still does some verifications (e.g.
122 * checking the name is a valid offset to the string section).
123 *
124 * Pass #2
125 * ~~~~~~~
126 * The main focus is to resolve a btf_type that is referring
127 * to another type.
128 *
129 * We have to ensure the referring type:
130 * 1) does exist in the BTF (i.e. in btf->types[])
131 * 2) does not cause a loop:
132 * struct A {
133 * struct B b;
134 * };
135 *
136 * struct B {
137 * struct A a;
138 * };
139 *
140 * btf_type_needs_resolve() decides if a btf_type needs
141 * to be resolved.
142 *
143 * The needs_resolve type implements the "resolve()" ops which
144 * essentially does a DFS and detects backedge.
145 *
146 * During resolve (or DFS), different C types have different
147 * "RESOLVED" conditions.
148 *
149 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
150 * members because a member is always referring to another
151 * type. A struct's member can be treated as "RESOLVED" if
152 * it is referring to a BTF_KIND_PTR. Otherwise, the
153 * following valid C struct would be rejected:
154 *
155 * struct A {
156 * int m;
157 * struct A *a;
158 * };
159 *
160 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
161 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
162 * detect a pointer loop, e.g.:
163 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
164 * ^ |
165 * +-----------------------------------------+
166 *
167 */
168
169#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
170#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
171#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
172#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
173#define BITS_ROUNDUP_BYTES(bits) \
174 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
175
176#define BTF_INFO_MASK 0x9f00ffff
177#define BTF_INT_MASK 0x0fffffff
178#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
179#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
180
181/* 16MB for 64k structs and each has 16 members and
182 * a few MB spaces for the string section.
183 * The hard limit is S32_MAX.
184 */
185#define BTF_MAX_SIZE (16 * 1024 * 1024)
186
187#define for_each_member_from(i, from, struct_type, member) \
188 for (i = from, member = btf_type_member(struct_type) + from; \
189 i < btf_type_vlen(struct_type); \
190 i++, member++)
191
192#define for_each_vsi_from(i, from, struct_type, member) \
193 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
194 i < btf_type_vlen(struct_type); \
195 i++, member++)
196
197DEFINE_IDR(btf_idr);
198DEFINE_SPINLOCK(btf_idr_lock);
199
200struct btf {
201 void *data;
202 struct btf_type **types;
203 u32 *resolved_ids;
204 u32 *resolved_sizes;
205 const char *strings;
206 void *nohdr_data;
207 struct btf_header hdr;
208 u32 nr_types; /* includes VOID for base BTF */
209 u32 types_size;
210 u32 data_size;
211 refcount_t refcnt;
212 u32 id;
213 struct rcu_head rcu;
214
215 /* split BTF support */
216 struct btf *base_btf;
217 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
218 u32 start_str_off; /* first string offset (0 for base BTF) */
219 char name[MODULE_NAME_LEN];
220 bool kernel_btf;
221};
222
223enum verifier_phase {
224 CHECK_META,
225 CHECK_TYPE,
226};
227
228struct resolve_vertex {
229 const struct btf_type *t;
230 u32 type_id;
231 u16 next_member;
232};
233
234enum visit_state {
235 NOT_VISITED,
236 VISITED,
237 RESOLVED,
238};
239
240enum resolve_mode {
241 RESOLVE_TBD, /* To Be Determined */
242 RESOLVE_PTR, /* Resolving for Pointer */
243 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
244 * or array
245 */
246};
247
248#define MAX_RESOLVE_DEPTH 32
249
250struct btf_sec_info {
251 u32 off;
252 u32 len;
253};
254
255struct btf_verifier_env {
256 struct btf *btf;
257 u8 *visit_states;
258 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
259 struct bpf_verifier_log log;
260 u32 log_type_id;
261 u32 top_stack;
262 enum verifier_phase phase;
263 enum resolve_mode resolve_mode;
264};
265
266static const char * const btf_kind_str[NR_BTF_KINDS] = {
267 [BTF_KIND_UNKN] = "UNKNOWN",
268 [BTF_KIND_INT] = "INT",
269 [BTF_KIND_PTR] = "PTR",
270 [BTF_KIND_ARRAY] = "ARRAY",
271 [BTF_KIND_STRUCT] = "STRUCT",
272 [BTF_KIND_UNION] = "UNION",
273 [BTF_KIND_ENUM] = "ENUM",
274 [BTF_KIND_FWD] = "FWD",
275 [BTF_KIND_TYPEDEF] = "TYPEDEF",
276 [BTF_KIND_VOLATILE] = "VOLATILE",
277 [BTF_KIND_CONST] = "CONST",
278 [BTF_KIND_RESTRICT] = "RESTRICT",
279 [BTF_KIND_FUNC] = "FUNC",
280 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
281 [BTF_KIND_VAR] = "VAR",
282 [BTF_KIND_DATASEC] = "DATASEC",
283 [BTF_KIND_FLOAT] = "FLOAT",
284};
285
286const char *btf_type_str(const struct btf_type *t)
287{
288 return btf_kind_str[BTF_INFO_KIND(t->info)];
289}
290
291/* Chunk size we use in safe copy of data to be shown. */
292#define BTF_SHOW_OBJ_SAFE_SIZE 32
293
294/*
295 * This is the maximum size of a base type value (equivalent to a
296 * 128-bit int); if we are at the end of our safe buffer and have
297 * less than 16 bytes space we can't be assured of being able
298 * to copy the next type safely, so in such cases we will initiate
299 * a new copy.
300 */
301#define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
302
303/* Type name size */
304#define BTF_SHOW_NAME_SIZE 80
305
306/*
307 * Common data to all BTF show operations. Private show functions can add
308 * their own data to a structure containing a struct btf_show and consult it
309 * in the show callback. See btf_type_show() below.
310 *
311 * One challenge with showing nested data is we want to skip 0-valued
312 * data, but in order to figure out whether a nested object is all zeros
313 * we need to walk through it. As a result, we need to make two passes
314 * when handling structs, unions and arrays; the first path simply looks
315 * for nonzero data, while the second actually does the display. The first
316 * pass is signalled by show->state.depth_check being set, and if we
317 * encounter a non-zero value we set show->state.depth_to_show to
318 * the depth at which we encountered it. When we have completed the
319 * first pass, we will know if anything needs to be displayed if
320 * depth_to_show > depth. See btf_[struct,array]_show() for the
321 * implementation of this.
322 *
323 * Another problem is we want to ensure the data for display is safe to
324 * access. To support this, the anonymous "struct {} obj" tracks the data
325 * object and our safe copy of it. We copy portions of the data needed
326 * to the object "copy" buffer, but because its size is limited to
327 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
328 * traverse larger objects for display.
329 *
330 * The various data type show functions all start with a call to
331 * btf_show_start_type() which returns a pointer to the safe copy
332 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
333 * raw data itself). btf_show_obj_safe() is responsible for
334 * using copy_from_kernel_nofault() to update the safe data if necessary
335 * as we traverse the object's data. skbuff-like semantics are
336 * used:
337 *
338 * - obj.head points to the start of the toplevel object for display
339 * - obj.size is the size of the toplevel object
340 * - obj.data points to the current point in the original data at
341 * which our safe data starts. obj.data will advance as we copy
342 * portions of the data.
343 *
344 * In most cases a single copy will suffice, but larger data structures
345 * such as "struct task_struct" will require many copies. The logic in
346 * btf_show_obj_safe() handles the logic that determines if a new
347 * copy_from_kernel_nofault() is needed.
348 */
349struct btf_show {
350 u64 flags;
351 void *target; /* target of show operation (seq file, buffer) */
352 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
353 const struct btf *btf;
354 /* below are used during iteration */
355 struct {
356 u8 depth;
357 u8 depth_to_show;
358 u8 depth_check;
359 u8 array_member:1,
360 array_terminated:1;
361 u16 array_encoding;
362 u32 type_id;
363 int status; /* non-zero for error */
364 const struct btf_type *type;
365 const struct btf_member *member;
366 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
367 } state;
368 struct {
369 u32 size;
370 void *head;
371 void *data;
372 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
373 } obj;
374};
375
376struct btf_kind_operations {
377 s32 (*check_meta)(struct btf_verifier_env *env,
378 const struct btf_type *t,
379 u32 meta_left);
380 int (*resolve)(struct btf_verifier_env *env,
381 const struct resolve_vertex *v);
382 int (*check_member)(struct btf_verifier_env *env,
383 const struct btf_type *struct_type,
384 const struct btf_member *member,
385 const struct btf_type *member_type);
386 int (*check_kflag_member)(struct btf_verifier_env *env,
387 const struct btf_type *struct_type,
388 const struct btf_member *member,
389 const struct btf_type *member_type);
390 void (*log_details)(struct btf_verifier_env *env,
391 const struct btf_type *t);
392 void (*show)(const struct btf *btf, const struct btf_type *t,
393 u32 type_id, void *data, u8 bits_offsets,
394 struct btf_show *show);
395};
396
397static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
398static struct btf_type btf_void;
399
400static int btf_resolve(struct btf_verifier_env *env,
401 const struct btf_type *t, u32 type_id);
402
403static bool btf_type_is_modifier(const struct btf_type *t)
404{
405 /* Some of them is not strictly a C modifier
406 * but they are grouped into the same bucket
407 * for BTF concern:
408 * A type (t) that refers to another
409 * type through t->type AND its size cannot
410 * be determined without following the t->type.
411 *
412 * ptr does not fall into this bucket
413 * because its size is always sizeof(void *).
414 */
415 switch (BTF_INFO_KIND(t->info)) {
416 case BTF_KIND_TYPEDEF:
417 case BTF_KIND_VOLATILE:
418 case BTF_KIND_CONST:
419 case BTF_KIND_RESTRICT:
420 return true;
421 }
422
423 return false;
424}
425
426bool btf_type_is_void(const struct btf_type *t)
427{
428 return t == &btf_void;
429}
430
431static bool btf_type_is_fwd(const struct btf_type *t)
432{
433 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
434}
435
436static bool btf_type_nosize(const struct btf_type *t)
437{
438 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
439 btf_type_is_func(t) || btf_type_is_func_proto(t);
440}
441
442static bool btf_type_nosize_or_null(const struct btf_type *t)
443{
444 return !t || btf_type_nosize(t);
445}
446
447static bool __btf_type_is_struct(const struct btf_type *t)
448{
449 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
450}
451
452static bool btf_type_is_array(const struct btf_type *t)
453{
454 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
455}
456
457static bool btf_type_is_datasec(const struct btf_type *t)
458{
459 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
460}
461
462u32 btf_nr_types(const struct btf *btf)
463{
464 u32 total = 0;
465
466 while (btf) {
467 total += btf->nr_types;
468 btf = btf->base_btf;
469 }
470
471 return total;
472}
473
474s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
475{
476 const struct btf_type *t;
477 const char *tname;
478 u32 i, total;
479
480 total = btf_nr_types(btf);
481 for (i = 1; i < total; i++) {
482 t = btf_type_by_id(btf, i);
483 if (BTF_INFO_KIND(t->info) != kind)
484 continue;
485
486 tname = btf_name_by_offset(btf, t->name_off);
487 if (!strcmp(tname, name))
488 return i;
489 }
490
491 return -ENOENT;
492}
493
494const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
495 u32 id, u32 *res_id)
496{
497 const struct btf_type *t = btf_type_by_id(btf, id);
498
499 while (btf_type_is_modifier(t)) {
500 id = t->type;
501 t = btf_type_by_id(btf, t->type);
502 }
503
504 if (res_id)
505 *res_id = id;
506
507 return t;
508}
509
510const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
511 u32 id, u32 *res_id)
512{
513 const struct btf_type *t;
514
515 t = btf_type_skip_modifiers(btf, id, NULL);
516 if (!btf_type_is_ptr(t))
517 return NULL;
518
519 return btf_type_skip_modifiers(btf, t->type, res_id);
520}
521
522const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
523 u32 id, u32 *res_id)
524{
525 const struct btf_type *ptype;
526
527 ptype = btf_type_resolve_ptr(btf, id, res_id);
528 if (ptype && btf_type_is_func_proto(ptype))
529 return ptype;
530
531 return NULL;
532}
533
534/* Types that act only as a source, not sink or intermediate
535 * type when resolving.
536 */
537static bool btf_type_is_resolve_source_only(const struct btf_type *t)
538{
539 return btf_type_is_var(t) ||
540 btf_type_is_datasec(t);
541}
542
543/* What types need to be resolved?
544 *
545 * btf_type_is_modifier() is an obvious one.
546 *
547 * btf_type_is_struct() because its member refers to
548 * another type (through member->type).
549 *
550 * btf_type_is_var() because the variable refers to
551 * another type. btf_type_is_datasec() holds multiple
552 * btf_type_is_var() types that need resolving.
553 *
554 * btf_type_is_array() because its element (array->type)
555 * refers to another type. Array can be thought of a
556 * special case of struct while array just has the same
557 * member-type repeated by array->nelems of times.
558 */
559static bool btf_type_needs_resolve(const struct btf_type *t)
560{
561 return btf_type_is_modifier(t) ||
562 btf_type_is_ptr(t) ||
563 btf_type_is_struct(t) ||
564 btf_type_is_array(t) ||
565 btf_type_is_var(t) ||
566 btf_type_is_datasec(t);
567}
568
569/* t->size can be used */
570static bool btf_type_has_size(const struct btf_type *t)
571{
572 switch (BTF_INFO_KIND(t->info)) {
573 case BTF_KIND_INT:
574 case BTF_KIND_STRUCT:
575 case BTF_KIND_UNION:
576 case BTF_KIND_ENUM:
577 case BTF_KIND_DATASEC:
578 case BTF_KIND_FLOAT:
579 return true;
580 }
581
582 return false;
583}
584
585static const char *btf_int_encoding_str(u8 encoding)
586{
587 if (encoding == 0)
588 return "(none)";
589 else if (encoding == BTF_INT_SIGNED)
590 return "SIGNED";
591 else if (encoding == BTF_INT_CHAR)
592 return "CHAR";
593 else if (encoding == BTF_INT_BOOL)
594 return "BOOL";
595 else
596 return "UNKN";
597}
598
599static u32 btf_type_int(const struct btf_type *t)
600{
601 return *(u32 *)(t + 1);
602}
603
604static const struct btf_array *btf_type_array(const struct btf_type *t)
605{
606 return (const struct btf_array *)(t + 1);
607}
608
609static const struct btf_enum *btf_type_enum(const struct btf_type *t)
610{
611 return (const struct btf_enum *)(t + 1);
612}
613
614static const struct btf_var *btf_type_var(const struct btf_type *t)
615{
616 return (const struct btf_var *)(t + 1);
617}
618
619static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
620{
621 return kind_ops[BTF_INFO_KIND(t->info)];
622}
623
624static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
625{
626 if (!BTF_STR_OFFSET_VALID(offset))
627 return false;
628
629 while (offset < btf->start_str_off)
630 btf = btf->base_btf;
631
632 offset -= btf->start_str_off;
633 return offset < btf->hdr.str_len;
634}
635
636static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
637{
638 if ((first ? !isalpha(c) :
639 !isalnum(c)) &&
640 c != '_' &&
641 ((c == '.' && !dot_ok) ||
642 c != '.'))
643 return false;
644 return true;
645}
646
647static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
648{
649 while (offset < btf->start_str_off)
650 btf = btf->base_btf;
651
652 offset -= btf->start_str_off;
653 if (offset < btf->hdr.str_len)
654 return &btf->strings[offset];
655
656 return NULL;
657}
658
659static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
660{
661 /* offset must be valid */
662 const char *src = btf_str_by_offset(btf, offset);
663 const char *src_limit;
664
665 if (!__btf_name_char_ok(*src, true, dot_ok))
666 return false;
667
668 /* set a limit on identifier length */
669 src_limit = src + KSYM_NAME_LEN;
670 src++;
671 while (*src && src < src_limit) {
672 if (!__btf_name_char_ok(*src, false, dot_ok))
673 return false;
674 src++;
675 }
676
677 return !*src;
678}
679
680/* Only C-style identifier is permitted. This can be relaxed if
681 * necessary.
682 */
683static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
684{
685 return __btf_name_valid(btf, offset, false);
686}
687
688static bool btf_name_valid_section(const struct btf *btf, u32 offset)
689{
690 return __btf_name_valid(btf, offset, true);
691}
692
693static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
694{
695 const char *name;
696
697 if (!offset)
698 return "(anon)";
699
700 name = btf_str_by_offset(btf, offset);
701 return name ?: "(invalid-name-offset)";
702}
703
704const char *btf_name_by_offset(const struct btf *btf, u32 offset)
705{
706 return btf_str_by_offset(btf, offset);
707}
708
709const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
710{
711 while (type_id < btf->start_id)
712 btf = btf->base_btf;
713
714 type_id -= btf->start_id;
715 if (type_id >= btf->nr_types)
716 return NULL;
717 return btf->types[type_id];
718}
719
720/*
721 * Regular int is not a bit field and it must be either
722 * u8/u16/u32/u64 or __int128.
723 */
724static bool btf_type_int_is_regular(const struct btf_type *t)
725{
726 u8 nr_bits, nr_bytes;
727 u32 int_data;
728
729 int_data = btf_type_int(t);
730 nr_bits = BTF_INT_BITS(int_data);
731 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
732 if (BITS_PER_BYTE_MASKED(nr_bits) ||
733 BTF_INT_OFFSET(int_data) ||
734 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
735 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
736 nr_bytes != (2 * sizeof(u64)))) {
737 return false;
738 }
739
740 return true;
741}
742
743/*
744 * Check that given struct member is a regular int with expected
745 * offset and size.
746 */
747bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
748 const struct btf_member *m,
749 u32 expected_offset, u32 expected_size)
750{
751 const struct btf_type *t;
752 u32 id, int_data;
753 u8 nr_bits;
754
755 id = m->type;
756 t = btf_type_id_size(btf, &id, NULL);
757 if (!t || !btf_type_is_int(t))
758 return false;
759
760 int_data = btf_type_int(t);
761 nr_bits = BTF_INT_BITS(int_data);
762 if (btf_type_kflag(s)) {
763 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
764 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
765
766 /* if kflag set, int should be a regular int and
767 * bit offset should be at byte boundary.
768 */
769 return !bitfield_size &&
770 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
771 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
772 }
773
774 if (BTF_INT_OFFSET(int_data) ||
775 BITS_PER_BYTE_MASKED(m->offset) ||
776 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
777 BITS_PER_BYTE_MASKED(nr_bits) ||
778 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
779 return false;
780
781 return true;
782}
783
784/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
785static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
786 u32 id)
787{
788 const struct btf_type *t = btf_type_by_id(btf, id);
789
790 while (btf_type_is_modifier(t) &&
791 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
792 t = btf_type_by_id(btf, t->type);
793 }
794
795 return t;
796}
797
798#define BTF_SHOW_MAX_ITER 10
799
800#define BTF_KIND_BIT(kind) (1ULL << kind)
801
802/*
803 * Populate show->state.name with type name information.
804 * Format of type name is
805 *
806 * [.member_name = ] (type_name)
807 */
808static const char *btf_show_name(struct btf_show *show)
809{
810 /* BTF_MAX_ITER array suffixes "[]" */
811 const char *array_suffixes = "[][][][][][][][][][]";
812 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
813 /* BTF_MAX_ITER pointer suffixes "*" */
814 const char *ptr_suffixes = "**********";
815 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
816 const char *name = NULL, *prefix = "", *parens = "";
817 const struct btf_member *m = show->state.member;
818 const struct btf_type *t = show->state.type;
819 const struct btf_array *array;
820 u32 id = show->state.type_id;
821 const char *member = NULL;
822 bool show_member = false;
823 u64 kinds = 0;
824 int i;
825
826 show->state.name[0] = '\0';
827
828 /*
829 * Don't show type name if we're showing an array member;
830 * in that case we show the array type so don't need to repeat
831 * ourselves for each member.
832 */
833 if (show->state.array_member)
834 return "";
835
836 /* Retrieve member name, if any. */
837 if (m) {
838 member = btf_name_by_offset(show->btf, m->name_off);
839 show_member = strlen(member) > 0;
840 id = m->type;
841 }
842
843 /*
844 * Start with type_id, as we have resolved the struct btf_type *
845 * via btf_modifier_show() past the parent typedef to the child
846 * struct, int etc it is defined as. In such cases, the type_id
847 * still represents the starting type while the struct btf_type *
848 * in our show->state points at the resolved type of the typedef.
849 */
850 t = btf_type_by_id(show->btf, id);
851 if (!t)
852 return "";
853
854 /*
855 * The goal here is to build up the right number of pointer and
856 * array suffixes while ensuring the type name for a typedef
857 * is represented. Along the way we accumulate a list of
858 * BTF kinds we have encountered, since these will inform later
859 * display; for example, pointer types will not require an
860 * opening "{" for struct, we will just display the pointer value.
861 *
862 * We also want to accumulate the right number of pointer or array
863 * indices in the format string while iterating until we get to
864 * the typedef/pointee/array member target type.
865 *
866 * We start by pointing at the end of pointer and array suffix
867 * strings; as we accumulate pointers and arrays we move the pointer
868 * or array string backwards so it will show the expected number of
869 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
870 * and/or arrays and typedefs are supported as a precaution.
871 *
872 * We also want to get typedef name while proceeding to resolve
873 * type it points to so that we can add parentheses if it is a
874 * "typedef struct" etc.
875 */
876 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
877
878 switch (BTF_INFO_KIND(t->info)) {
879 case BTF_KIND_TYPEDEF:
880 if (!name)
881 name = btf_name_by_offset(show->btf,
882 t->name_off);
883 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
884 id = t->type;
885 break;
886 case BTF_KIND_ARRAY:
887 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
888 parens = "[";
889 if (!t)
890 return "";
891 array = btf_type_array(t);
892 if (array_suffix > array_suffixes)
893 array_suffix -= 2;
894 id = array->type;
895 break;
896 case BTF_KIND_PTR:
897 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
898 if (ptr_suffix > ptr_suffixes)
899 ptr_suffix -= 1;
900 id = t->type;
901 break;
902 default:
903 id = 0;
904 break;
905 }
906 if (!id)
907 break;
908 t = btf_type_skip_qualifiers(show->btf, id);
909 }
910 /* We may not be able to represent this type; bail to be safe */
911 if (i == BTF_SHOW_MAX_ITER)
912 return "";
913
914 if (!name)
915 name = btf_name_by_offset(show->btf, t->name_off);
916
917 switch (BTF_INFO_KIND(t->info)) {
918 case BTF_KIND_STRUCT:
919 case BTF_KIND_UNION:
920 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
921 "struct" : "union";
922 /* if it's an array of struct/union, parens is already set */
923 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
924 parens = "{";
925 break;
926 case BTF_KIND_ENUM:
927 prefix = "enum";
928 break;
929 default:
930 break;
931 }
932
933 /* pointer does not require parens */
934 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
935 parens = "";
936 /* typedef does not require struct/union/enum prefix */
937 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
938 prefix = "";
939
940 if (!name)
941 name = "";
942
943 /* Even if we don't want type name info, we want parentheses etc */
944 if (show->flags & BTF_SHOW_NONAME)
945 snprintf(show->state.name, sizeof(show->state.name), "%s",
946 parens);
947 else
948 snprintf(show->state.name, sizeof(show->state.name),
949 "%s%s%s(%s%s%s%s%s%s)%s",
950 /* first 3 strings comprise ".member = " */
951 show_member ? "." : "",
952 show_member ? member : "",
953 show_member ? " = " : "",
954 /* ...next is our prefix (struct, enum, etc) */
955 prefix,
956 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
957 /* ...this is the type name itself */
958 name,
959 /* ...suffixed by the appropriate '*', '[]' suffixes */
960 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
961 array_suffix, parens);
962
963 return show->state.name;
964}
965
966static const char *__btf_show_indent(struct btf_show *show)
967{
968 const char *indents = " ";
969 const char *indent = &indents[strlen(indents)];
970
971 if ((indent - show->state.depth) >= indents)
972 return indent - show->state.depth;
973 return indents;
974}
975
976static const char *btf_show_indent(struct btf_show *show)
977{
978 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
979}
980
981static const char *btf_show_newline(struct btf_show *show)
982{
983 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
984}
985
986static const char *btf_show_delim(struct btf_show *show)
987{
988 if (show->state.depth == 0)
989 return "";
990
991 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
992 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
993 return "|";
994
995 return ",";
996}
997
998__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
999{
1000 va_list args;
1001
1002 if (!show->state.depth_check) {
1003 va_start(args, fmt);
1004 show->showfn(show, fmt, args);
1005 va_end(args);
1006 }
1007}
1008
1009/* Macros are used here as btf_show_type_value[s]() prepends and appends
1010 * format specifiers to the format specifier passed in; these do the work of
1011 * adding indentation, delimiters etc while the caller simply has to specify
1012 * the type value(s) in the format specifier + value(s).
1013 */
1014#define btf_show_type_value(show, fmt, value) \
1015 do { \
1016 if ((value) != 0 || (show->flags & BTF_SHOW_ZERO) || \
1017 show->state.depth == 0) { \
1018 btf_show(show, "%s%s" fmt "%s%s", \
1019 btf_show_indent(show), \
1020 btf_show_name(show), \
1021 value, btf_show_delim(show), \
1022 btf_show_newline(show)); \
1023 if (show->state.depth > show->state.depth_to_show) \
1024 show->state.depth_to_show = show->state.depth; \
1025 } \
1026 } while (0)
1027
1028#define btf_show_type_values(show, fmt, ...) \
1029 do { \
1030 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1031 btf_show_name(show), \
1032 __VA_ARGS__, btf_show_delim(show), \
1033 btf_show_newline(show)); \
1034 if (show->state.depth > show->state.depth_to_show) \
1035 show->state.depth_to_show = show->state.depth; \
1036 } while (0)
1037
1038/* How much is left to copy to safe buffer after @data? */
1039static int btf_show_obj_size_left(struct btf_show *show, void *data)
1040{
1041 return show->obj.head + show->obj.size - data;
1042}
1043
1044/* Is object pointed to by @data of @size already copied to our safe buffer? */
1045static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1046{
1047 return data >= show->obj.data &&
1048 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1049}
1050
1051/*
1052 * If object pointed to by @data of @size falls within our safe buffer, return
1053 * the equivalent pointer to the same safe data. Assumes
1054 * copy_from_kernel_nofault() has already happened and our safe buffer is
1055 * populated.
1056 */
1057static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1058{
1059 if (btf_show_obj_is_safe(show, data, size))
1060 return show->obj.safe + (data - show->obj.data);
1061 return NULL;
1062}
1063
1064/*
1065 * Return a safe-to-access version of data pointed to by @data.
1066 * We do this by copying the relevant amount of information
1067 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1068 *
1069 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1070 * safe copy is needed.
1071 *
1072 * Otherwise we need to determine if we have the required amount
1073 * of data (determined by the @data pointer and the size of the
1074 * largest base type we can encounter (represented by
1075 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1076 * that we will be able to print some of the current object,
1077 * and if more is needed a copy will be triggered.
1078 * Some objects such as structs will not fit into the buffer;
1079 * in such cases additional copies when we iterate over their
1080 * members may be needed.
1081 *
1082 * btf_show_obj_safe() is used to return a safe buffer for
1083 * btf_show_start_type(); this ensures that as we recurse into
1084 * nested types we always have safe data for the given type.
1085 * This approach is somewhat wasteful; it's possible for example
1086 * that when iterating over a large union we'll end up copying the
1087 * same data repeatedly, but the goal is safety not performance.
1088 * We use stack data as opposed to per-CPU buffers because the
1089 * iteration over a type can take some time, and preemption handling
1090 * would greatly complicate use of the safe buffer.
1091 */
1092static void *btf_show_obj_safe(struct btf_show *show,
1093 const struct btf_type *t,
1094 void *data)
1095{
1096 const struct btf_type *rt;
1097 int size_left, size;
1098 void *safe = NULL;
1099
1100 if (show->flags & BTF_SHOW_UNSAFE)
1101 return data;
1102
1103 rt = btf_resolve_size(show->btf, t, &size);
1104 if (IS_ERR(rt)) {
1105 show->state.status = PTR_ERR(rt);
1106 return NULL;
1107 }
1108
1109 /*
1110 * Is this toplevel object? If so, set total object size and
1111 * initialize pointers. Otherwise check if we still fall within
1112 * our safe object data.
1113 */
1114 if (show->state.depth == 0) {
1115 show->obj.size = size;
1116 show->obj.head = data;
1117 } else {
1118 /*
1119 * If the size of the current object is > our remaining
1120 * safe buffer we _may_ need to do a new copy. However
1121 * consider the case of a nested struct; it's size pushes
1122 * us over the safe buffer limit, but showing any individual
1123 * struct members does not. In such cases, we don't need
1124 * to initiate a fresh copy yet; however we definitely need
1125 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1126 * in our buffer, regardless of the current object size.
1127 * The logic here is that as we resolve types we will
1128 * hit a base type at some point, and we need to be sure
1129 * the next chunk of data is safely available to display
1130 * that type info safely. We cannot rely on the size of
1131 * the current object here because it may be much larger
1132 * than our current buffer (e.g. task_struct is 8k).
1133 * All we want to do here is ensure that we can print the
1134 * next basic type, which we can if either
1135 * - the current type size is within the safe buffer; or
1136 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1137 * the safe buffer.
1138 */
1139 safe = __btf_show_obj_safe(show, data,
1140 min(size,
1141 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1142 }
1143
1144 /*
1145 * We need a new copy to our safe object, either because we haven't
1146 * yet copied and are initializing safe data, or because the data
1147 * we want falls outside the boundaries of the safe object.
1148 */
1149 if (!safe) {
1150 size_left = btf_show_obj_size_left(show, data);
1151 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1152 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1153 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1154 data, size_left);
1155 if (!show->state.status) {
1156 show->obj.data = data;
1157 safe = show->obj.safe;
1158 }
1159 }
1160
1161 return safe;
1162}
1163
1164/*
1165 * Set the type we are starting to show and return a safe data pointer
1166 * to be used for showing the associated data.
1167 */
1168static void *btf_show_start_type(struct btf_show *show,
1169 const struct btf_type *t,
1170 u32 type_id, void *data)
1171{
1172 show->state.type = t;
1173 show->state.type_id = type_id;
1174 show->state.name[0] = '\0';
1175
1176 return btf_show_obj_safe(show, t, data);
1177}
1178
1179static void btf_show_end_type(struct btf_show *show)
1180{
1181 show->state.type = NULL;
1182 show->state.type_id = 0;
1183 show->state.name[0] = '\0';
1184}
1185
1186static void *btf_show_start_aggr_type(struct btf_show *show,
1187 const struct btf_type *t,
1188 u32 type_id, void *data)
1189{
1190 void *safe_data = btf_show_start_type(show, t, type_id, data);
1191
1192 if (!safe_data)
1193 return safe_data;
1194
1195 btf_show(show, "%s%s%s", btf_show_indent(show),
1196 btf_show_name(show),
1197 btf_show_newline(show));
1198 show->state.depth++;
1199 return safe_data;
1200}
1201
1202static void btf_show_end_aggr_type(struct btf_show *show,
1203 const char *suffix)
1204{
1205 show->state.depth--;
1206 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1207 btf_show_delim(show), btf_show_newline(show));
1208 btf_show_end_type(show);
1209}
1210
1211static void btf_show_start_member(struct btf_show *show,
1212 const struct btf_member *m)
1213{
1214 show->state.member = m;
1215}
1216
1217static void btf_show_start_array_member(struct btf_show *show)
1218{
1219 show->state.array_member = 1;
1220 btf_show_start_member(show, NULL);
1221}
1222
1223static void btf_show_end_member(struct btf_show *show)
1224{
1225 show->state.member = NULL;
1226}
1227
1228static void btf_show_end_array_member(struct btf_show *show)
1229{
1230 show->state.array_member = 0;
1231 btf_show_end_member(show);
1232}
1233
1234static void *btf_show_start_array_type(struct btf_show *show,
1235 const struct btf_type *t,
1236 u32 type_id,
1237 u16 array_encoding,
1238 void *data)
1239{
1240 show->state.array_encoding = array_encoding;
1241 show->state.array_terminated = 0;
1242 return btf_show_start_aggr_type(show, t, type_id, data);
1243}
1244
1245static void btf_show_end_array_type(struct btf_show *show)
1246{
1247 show->state.array_encoding = 0;
1248 show->state.array_terminated = 0;
1249 btf_show_end_aggr_type(show, "]");
1250}
1251
1252static void *btf_show_start_struct_type(struct btf_show *show,
1253 const struct btf_type *t,
1254 u32 type_id,
1255 void *data)
1256{
1257 return btf_show_start_aggr_type(show, t, type_id, data);
1258}
1259
1260static void btf_show_end_struct_type(struct btf_show *show)
1261{
1262 btf_show_end_aggr_type(show, "}");
1263}
1264
1265__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1266 const char *fmt, ...)
1267{
1268 va_list args;
1269
1270 va_start(args, fmt);
1271 bpf_verifier_vlog(log, fmt, args);
1272 va_end(args);
1273}
1274
1275__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1276 const char *fmt, ...)
1277{
1278 struct bpf_verifier_log *log = &env->log;
1279 va_list args;
1280
1281 if (!bpf_verifier_log_needed(log))
1282 return;
1283
1284 va_start(args, fmt);
1285 bpf_verifier_vlog(log, fmt, args);
1286 va_end(args);
1287}
1288
1289__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1290 const struct btf_type *t,
1291 bool log_details,
1292 const char *fmt, ...)
1293{
1294 struct bpf_verifier_log *log = &env->log;
1295 u8 kind = BTF_INFO_KIND(t->info);
1296 struct btf *btf = env->btf;
1297 va_list args;
1298
1299 if (!bpf_verifier_log_needed(log))
1300 return;
1301
1302 /* btf verifier prints all types it is processing via
1303 * btf_verifier_log_type(..., fmt = NULL).
1304 * Skip those prints for in-kernel BTF verification.
1305 */
1306 if (log->level == BPF_LOG_KERNEL && !fmt)
1307 return;
1308
1309 __btf_verifier_log(log, "[%u] %s %s%s",
1310 env->log_type_id,
1311 btf_kind_str[kind],
1312 __btf_name_by_offset(btf, t->name_off),
1313 log_details ? " " : "");
1314
1315 if (log_details)
1316 btf_type_ops(t)->log_details(env, t);
1317
1318 if (fmt && *fmt) {
1319 __btf_verifier_log(log, " ");
1320 va_start(args, fmt);
1321 bpf_verifier_vlog(log, fmt, args);
1322 va_end(args);
1323 }
1324
1325 __btf_verifier_log(log, "\n");
1326}
1327
1328#define btf_verifier_log_type(env, t, ...) \
1329 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1330#define btf_verifier_log_basic(env, t, ...) \
1331 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1332
1333__printf(4, 5)
1334static void btf_verifier_log_member(struct btf_verifier_env *env,
1335 const struct btf_type *struct_type,
1336 const struct btf_member *member,
1337 const char *fmt, ...)
1338{
1339 struct bpf_verifier_log *log = &env->log;
1340 struct btf *btf = env->btf;
1341 va_list args;
1342
1343 if (!bpf_verifier_log_needed(log))
1344 return;
1345
1346 if (log->level == BPF_LOG_KERNEL && !fmt)
1347 return;
1348 /* The CHECK_META phase already did a btf dump.
1349 *
1350 * If member is logged again, it must hit an error in
1351 * parsing this member. It is useful to print out which
1352 * struct this member belongs to.
1353 */
1354 if (env->phase != CHECK_META)
1355 btf_verifier_log_type(env, struct_type, NULL);
1356
1357 if (btf_type_kflag(struct_type))
1358 __btf_verifier_log(log,
1359 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1360 __btf_name_by_offset(btf, member->name_off),
1361 member->type,
1362 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1363 BTF_MEMBER_BIT_OFFSET(member->offset));
1364 else
1365 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1366 __btf_name_by_offset(btf, member->name_off),
1367 member->type, member->offset);
1368
1369 if (fmt && *fmt) {
1370 __btf_verifier_log(log, " ");
1371 va_start(args, fmt);
1372 bpf_verifier_vlog(log, fmt, args);
1373 va_end(args);
1374 }
1375
1376 __btf_verifier_log(log, "\n");
1377}
1378
1379__printf(4, 5)
1380static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1381 const struct btf_type *datasec_type,
1382 const struct btf_var_secinfo *vsi,
1383 const char *fmt, ...)
1384{
1385 struct bpf_verifier_log *log = &env->log;
1386 va_list args;
1387
1388 if (!bpf_verifier_log_needed(log))
1389 return;
1390 if (log->level == BPF_LOG_KERNEL && !fmt)
1391 return;
1392 if (env->phase != CHECK_META)
1393 btf_verifier_log_type(env, datasec_type, NULL);
1394
1395 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1396 vsi->type, vsi->offset, vsi->size);
1397 if (fmt && *fmt) {
1398 __btf_verifier_log(log, " ");
1399 va_start(args, fmt);
1400 bpf_verifier_vlog(log, fmt, args);
1401 va_end(args);
1402 }
1403
1404 __btf_verifier_log(log, "\n");
1405}
1406
1407static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1408 u32 btf_data_size)
1409{
1410 struct bpf_verifier_log *log = &env->log;
1411 const struct btf *btf = env->btf;
1412 const struct btf_header *hdr;
1413
1414 if (!bpf_verifier_log_needed(log))
1415 return;
1416
1417 if (log->level == BPF_LOG_KERNEL)
1418 return;
1419 hdr = &btf->hdr;
1420 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1421 __btf_verifier_log(log, "version: %u\n", hdr->version);
1422 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1423 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1424 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1425 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1426 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1427 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1428 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1429}
1430
1431static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1432{
1433 struct btf *btf = env->btf;
1434
1435 if (btf->types_size == btf->nr_types) {
1436 /* Expand 'types' array */
1437
1438 struct btf_type **new_types;
1439 u32 expand_by, new_size;
1440
1441 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1442 btf_verifier_log(env, "Exceeded max num of types");
1443 return -E2BIG;
1444 }
1445
1446 expand_by = max_t(u32, btf->types_size >> 2, 16);
1447 new_size = min_t(u32, BTF_MAX_TYPE,
1448 btf->types_size + expand_by);
1449
1450 new_types = kvcalloc(new_size, sizeof(*new_types),
1451 GFP_KERNEL | __GFP_NOWARN);
1452 if (!new_types)
1453 return -ENOMEM;
1454
1455 if (btf->nr_types == 0) {
1456 if (!btf->base_btf) {
1457 /* lazily init VOID type */
1458 new_types[0] = &btf_void;
1459 btf->nr_types++;
1460 }
1461 } else {
1462 memcpy(new_types, btf->types,
1463 sizeof(*btf->types) * btf->nr_types);
1464 }
1465
1466 kvfree(btf->types);
1467 btf->types = new_types;
1468 btf->types_size = new_size;
1469 }
1470
1471 btf->types[btf->nr_types++] = t;
1472
1473 return 0;
1474}
1475
1476static int btf_alloc_id(struct btf *btf)
1477{
1478 int id;
1479
1480 idr_preload(GFP_KERNEL);
1481 spin_lock_bh(&btf_idr_lock);
1482 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1483 if (id > 0)
1484 btf->id = id;
1485 spin_unlock_bh(&btf_idr_lock);
1486 idr_preload_end();
1487
1488 if (WARN_ON_ONCE(!id))
1489 return -ENOSPC;
1490
1491 return id > 0 ? 0 : id;
1492}
1493
1494static void btf_free_id(struct btf *btf)
1495{
1496 unsigned long flags;
1497
1498 /*
1499 * In map-in-map, calling map_delete_elem() on outer
1500 * map will call bpf_map_put on the inner map.
1501 * It will then eventually call btf_free_id()
1502 * on the inner map. Some of the map_delete_elem()
1503 * implementation may have irq disabled, so
1504 * we need to use the _irqsave() version instead
1505 * of the _bh() version.
1506 */
1507 spin_lock_irqsave(&btf_idr_lock, flags);
1508 idr_remove(&btf_idr, btf->id);
1509 spin_unlock_irqrestore(&btf_idr_lock, flags);
1510}
1511
1512static void btf_free(struct btf *btf)
1513{
1514 kvfree(btf->types);
1515 kvfree(btf->resolved_sizes);
1516 kvfree(btf->resolved_ids);
1517 kvfree(btf->data);
1518 kfree(btf);
1519}
1520
1521static void btf_free_rcu(struct rcu_head *rcu)
1522{
1523 struct btf *btf = container_of(rcu, struct btf, rcu);
1524
1525 btf_free(btf);
1526}
1527
1528void btf_get(struct btf *btf)
1529{
1530 refcount_inc(&btf->refcnt);
1531}
1532
1533void btf_put(struct btf *btf)
1534{
1535 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1536 btf_free_id(btf);
1537 call_rcu(&btf->rcu, btf_free_rcu);
1538 }
1539}
1540
1541static int env_resolve_init(struct btf_verifier_env *env)
1542{
1543 struct btf *btf = env->btf;
1544 u32 nr_types = btf->nr_types;
1545 u32 *resolved_sizes = NULL;
1546 u32 *resolved_ids = NULL;
1547 u8 *visit_states = NULL;
1548
1549 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1550 GFP_KERNEL | __GFP_NOWARN);
1551 if (!resolved_sizes)
1552 goto nomem;
1553
1554 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1555 GFP_KERNEL | __GFP_NOWARN);
1556 if (!resolved_ids)
1557 goto nomem;
1558
1559 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1560 GFP_KERNEL | __GFP_NOWARN);
1561 if (!visit_states)
1562 goto nomem;
1563
1564 btf->resolved_sizes = resolved_sizes;
1565 btf->resolved_ids = resolved_ids;
1566 env->visit_states = visit_states;
1567
1568 return 0;
1569
1570nomem:
1571 kvfree(resolved_sizes);
1572 kvfree(resolved_ids);
1573 kvfree(visit_states);
1574 return -ENOMEM;
1575}
1576
1577static void btf_verifier_env_free(struct btf_verifier_env *env)
1578{
1579 kvfree(env->visit_states);
1580 kfree(env);
1581}
1582
1583static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1584 const struct btf_type *next_type)
1585{
1586 switch (env->resolve_mode) {
1587 case RESOLVE_TBD:
1588 /* int, enum or void is a sink */
1589 return !btf_type_needs_resolve(next_type);
1590 case RESOLVE_PTR:
1591 /* int, enum, void, struct, array, func or func_proto is a sink
1592 * for ptr
1593 */
1594 return !btf_type_is_modifier(next_type) &&
1595 !btf_type_is_ptr(next_type);
1596 case RESOLVE_STRUCT_OR_ARRAY:
1597 /* int, enum, void, ptr, func or func_proto is a sink
1598 * for struct and array
1599 */
1600 return !btf_type_is_modifier(next_type) &&
1601 !btf_type_is_array(next_type) &&
1602 !btf_type_is_struct(next_type);
1603 default:
1604 BUG();
1605 }
1606}
1607
1608static bool env_type_is_resolved(const struct btf_verifier_env *env,
1609 u32 type_id)
1610{
1611 /* base BTF types should be resolved by now */
1612 if (type_id < env->btf->start_id)
1613 return true;
1614
1615 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1616}
1617
1618static int env_stack_push(struct btf_verifier_env *env,
1619 const struct btf_type *t, u32 type_id)
1620{
1621 const struct btf *btf = env->btf;
1622 struct resolve_vertex *v;
1623
1624 if (env->top_stack == MAX_RESOLVE_DEPTH)
1625 return -E2BIG;
1626
1627 if (type_id < btf->start_id
1628 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1629 return -EEXIST;
1630
1631 env->visit_states[type_id - btf->start_id] = VISITED;
1632
1633 v = &env->stack[env->top_stack++];
1634 v->t = t;
1635 v->type_id = type_id;
1636 v->next_member = 0;
1637
1638 if (env->resolve_mode == RESOLVE_TBD) {
1639 if (btf_type_is_ptr(t))
1640 env->resolve_mode = RESOLVE_PTR;
1641 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1642 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1643 }
1644
1645 return 0;
1646}
1647
1648static void env_stack_set_next_member(struct btf_verifier_env *env,
1649 u16 next_member)
1650{
1651 env->stack[env->top_stack - 1].next_member = next_member;
1652}
1653
1654static void env_stack_pop_resolved(struct btf_verifier_env *env,
1655 u32 resolved_type_id,
1656 u32 resolved_size)
1657{
1658 u32 type_id = env->stack[--(env->top_stack)].type_id;
1659 struct btf *btf = env->btf;
1660
1661 type_id -= btf->start_id; /* adjust to local type id */
1662 btf->resolved_sizes[type_id] = resolved_size;
1663 btf->resolved_ids[type_id] = resolved_type_id;
1664 env->visit_states[type_id] = RESOLVED;
1665}
1666
1667static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1668{
1669 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1670}
1671
1672/* Resolve the size of a passed-in "type"
1673 *
1674 * type: is an array (e.g. u32 array[x][y])
1675 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1676 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1677 * corresponds to the return type.
1678 * *elem_type: u32
1679 * *elem_id: id of u32
1680 * *total_nelems: (x * y). Hence, individual elem size is
1681 * (*type_size / *total_nelems)
1682 * *type_id: id of type if it's changed within the function, 0 if not
1683 *
1684 * type: is not an array (e.g. const struct X)
1685 * return type: type "struct X"
1686 * *type_size: sizeof(struct X)
1687 * *elem_type: same as return type ("struct X")
1688 * *elem_id: 0
1689 * *total_nelems: 1
1690 * *type_id: id of type if it's changed within the function, 0 if not
1691 */
1692static const struct btf_type *
1693__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1694 u32 *type_size, const struct btf_type **elem_type,
1695 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1696{
1697 const struct btf_type *array_type = NULL;
1698 const struct btf_array *array = NULL;
1699 u32 i, size, nelems = 1, id = 0;
1700
1701 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1702 switch (BTF_INFO_KIND(type->info)) {
1703 /* type->size can be used */
1704 case BTF_KIND_INT:
1705 case BTF_KIND_STRUCT:
1706 case BTF_KIND_UNION:
1707 case BTF_KIND_ENUM:
1708 case BTF_KIND_FLOAT:
1709 size = type->size;
1710 goto resolved;
1711
1712 case BTF_KIND_PTR:
1713 size = sizeof(void *);
1714 goto resolved;
1715
1716 /* Modifiers */
1717 case BTF_KIND_TYPEDEF:
1718 case BTF_KIND_VOLATILE:
1719 case BTF_KIND_CONST:
1720 case BTF_KIND_RESTRICT:
1721 id = type->type;
1722 type = btf_type_by_id(btf, type->type);
1723 break;
1724
1725 case BTF_KIND_ARRAY:
1726 if (!array_type)
1727 array_type = type;
1728 array = btf_type_array(type);
1729 if (nelems && array->nelems > U32_MAX / nelems)
1730 return ERR_PTR(-EINVAL);
1731 nelems *= array->nelems;
1732 type = btf_type_by_id(btf, array->type);
1733 break;
1734
1735 /* type without size */
1736 default:
1737 return ERR_PTR(-EINVAL);
1738 }
1739 }
1740
1741 return ERR_PTR(-EINVAL);
1742
1743resolved:
1744 if (nelems && size > U32_MAX / nelems)
1745 return ERR_PTR(-EINVAL);
1746
1747 *type_size = nelems * size;
1748 if (total_nelems)
1749 *total_nelems = nelems;
1750 if (elem_type)
1751 *elem_type = type;
1752 if (elem_id)
1753 *elem_id = array ? array->type : 0;
1754 if (type_id && id)
1755 *type_id = id;
1756
1757 return array_type ? : type;
1758}
1759
1760const struct btf_type *
1761btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1762 u32 *type_size)
1763{
1764 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1765}
1766
1767static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1768{
1769 while (type_id < btf->start_id)
1770 btf = btf->base_btf;
1771
1772 return btf->resolved_ids[type_id - btf->start_id];
1773}
1774
1775/* The input param "type_id" must point to a needs_resolve type */
1776static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1777 u32 *type_id)
1778{
1779 *type_id = btf_resolved_type_id(btf, *type_id);
1780 return btf_type_by_id(btf, *type_id);
1781}
1782
1783static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1784{
1785 while (type_id < btf->start_id)
1786 btf = btf->base_btf;
1787
1788 return btf->resolved_sizes[type_id - btf->start_id];
1789}
1790
1791const struct btf_type *btf_type_id_size(const struct btf *btf,
1792 u32 *type_id, u32 *ret_size)
1793{
1794 const struct btf_type *size_type;
1795 u32 size_type_id = *type_id;
1796 u32 size = 0;
1797
1798 size_type = btf_type_by_id(btf, size_type_id);
1799 if (btf_type_nosize_or_null(size_type))
1800 return NULL;
1801
1802 if (btf_type_has_size(size_type)) {
1803 size = size_type->size;
1804 } else if (btf_type_is_array(size_type)) {
1805 size = btf_resolved_type_size(btf, size_type_id);
1806 } else if (btf_type_is_ptr(size_type)) {
1807 size = sizeof(void *);
1808 } else {
1809 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1810 !btf_type_is_var(size_type)))
1811 return NULL;
1812
1813 size_type_id = btf_resolved_type_id(btf, size_type_id);
1814 size_type = btf_type_by_id(btf, size_type_id);
1815 if (btf_type_nosize_or_null(size_type))
1816 return NULL;
1817 else if (btf_type_has_size(size_type))
1818 size = size_type->size;
1819 else if (btf_type_is_array(size_type))
1820 size = btf_resolved_type_size(btf, size_type_id);
1821 else if (btf_type_is_ptr(size_type))
1822 size = sizeof(void *);
1823 else
1824 return NULL;
1825 }
1826
1827 *type_id = size_type_id;
1828 if (ret_size)
1829 *ret_size = size;
1830
1831 return size_type;
1832}
1833
1834static int btf_df_check_member(struct btf_verifier_env *env,
1835 const struct btf_type *struct_type,
1836 const struct btf_member *member,
1837 const struct btf_type *member_type)
1838{
1839 btf_verifier_log_basic(env, struct_type,
1840 "Unsupported check_member");
1841 return -EINVAL;
1842}
1843
1844static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1845 const struct btf_type *struct_type,
1846 const struct btf_member *member,
1847 const struct btf_type *member_type)
1848{
1849 btf_verifier_log_basic(env, struct_type,
1850 "Unsupported check_kflag_member");
1851 return -EINVAL;
1852}
1853
1854/* Used for ptr, array struct/union and float type members.
1855 * int, enum and modifier types have their specific callback functions.
1856 */
1857static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1858 const struct btf_type *struct_type,
1859 const struct btf_member *member,
1860 const struct btf_type *member_type)
1861{
1862 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
1863 btf_verifier_log_member(env, struct_type, member,
1864 "Invalid member bitfield_size");
1865 return -EINVAL;
1866 }
1867
1868 /* bitfield size is 0, so member->offset represents bit offset only.
1869 * It is safe to call non kflag check_member variants.
1870 */
1871 return btf_type_ops(member_type)->check_member(env, struct_type,
1872 member,
1873 member_type);
1874}
1875
1876static int btf_df_resolve(struct btf_verifier_env *env,
1877 const struct resolve_vertex *v)
1878{
1879 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
1880 return -EINVAL;
1881}
1882
1883static void btf_df_show(const struct btf *btf, const struct btf_type *t,
1884 u32 type_id, void *data, u8 bits_offsets,
1885 struct btf_show *show)
1886{
1887 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
1888}
1889
1890static int btf_int_check_member(struct btf_verifier_env *env,
1891 const struct btf_type *struct_type,
1892 const struct btf_member *member,
1893 const struct btf_type *member_type)
1894{
1895 u32 int_data = btf_type_int(member_type);
1896 u32 struct_bits_off = member->offset;
1897 u32 struct_size = struct_type->size;
1898 u32 nr_copy_bits;
1899 u32 bytes_offset;
1900
1901 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
1902 btf_verifier_log_member(env, struct_type, member,
1903 "bits_offset exceeds U32_MAX");
1904 return -EINVAL;
1905 }
1906
1907 struct_bits_off += BTF_INT_OFFSET(int_data);
1908 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1909 nr_copy_bits = BTF_INT_BITS(int_data) +
1910 BITS_PER_BYTE_MASKED(struct_bits_off);
1911
1912 if (nr_copy_bits > BITS_PER_U128) {
1913 btf_verifier_log_member(env, struct_type, member,
1914 "nr_copy_bits exceeds 128");
1915 return -EINVAL;
1916 }
1917
1918 if (struct_size < bytes_offset ||
1919 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1920 btf_verifier_log_member(env, struct_type, member,
1921 "Member exceeds struct_size");
1922 return -EINVAL;
1923 }
1924
1925 return 0;
1926}
1927
1928static int btf_int_check_kflag_member(struct btf_verifier_env *env,
1929 const struct btf_type *struct_type,
1930 const struct btf_member *member,
1931 const struct btf_type *member_type)
1932{
1933 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
1934 u32 int_data = btf_type_int(member_type);
1935 u32 struct_size = struct_type->size;
1936 u32 nr_copy_bits;
1937
1938 /* a regular int type is required for the kflag int member */
1939 if (!btf_type_int_is_regular(member_type)) {
1940 btf_verifier_log_member(env, struct_type, member,
1941 "Invalid member base type");
1942 return -EINVAL;
1943 }
1944
1945 /* check sanity of bitfield size */
1946 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
1947 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
1948 nr_int_data_bits = BTF_INT_BITS(int_data);
1949 if (!nr_bits) {
1950 /* Not a bitfield member, member offset must be at byte
1951 * boundary.
1952 */
1953 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1954 btf_verifier_log_member(env, struct_type, member,
1955 "Invalid member offset");
1956 return -EINVAL;
1957 }
1958
1959 nr_bits = nr_int_data_bits;
1960 } else if (nr_bits > nr_int_data_bits) {
1961 btf_verifier_log_member(env, struct_type, member,
1962 "Invalid member bitfield_size");
1963 return -EINVAL;
1964 }
1965
1966 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1967 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
1968 if (nr_copy_bits > BITS_PER_U128) {
1969 btf_verifier_log_member(env, struct_type, member,
1970 "nr_copy_bits exceeds 128");
1971 return -EINVAL;
1972 }
1973
1974 if (struct_size < bytes_offset ||
1975 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1976 btf_verifier_log_member(env, struct_type, member,
1977 "Member exceeds struct_size");
1978 return -EINVAL;
1979 }
1980
1981 return 0;
1982}
1983
1984static s32 btf_int_check_meta(struct btf_verifier_env *env,
1985 const struct btf_type *t,
1986 u32 meta_left)
1987{
1988 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
1989 u16 encoding;
1990
1991 if (meta_left < meta_needed) {
1992 btf_verifier_log_basic(env, t,
1993 "meta_left:%u meta_needed:%u",
1994 meta_left, meta_needed);
1995 return -EINVAL;
1996 }
1997
1998 if (btf_type_vlen(t)) {
1999 btf_verifier_log_type(env, t, "vlen != 0");
2000 return -EINVAL;
2001 }
2002
2003 if (btf_type_kflag(t)) {
2004 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2005 return -EINVAL;
2006 }
2007
2008 int_data = btf_type_int(t);
2009 if (int_data & ~BTF_INT_MASK) {
2010 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2011 int_data);
2012 return -EINVAL;
2013 }
2014
2015 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2016
2017 if (nr_bits > BITS_PER_U128) {
2018 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2019 BITS_PER_U128);
2020 return -EINVAL;
2021 }
2022
2023 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2024 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2025 return -EINVAL;
2026 }
2027
2028 /*
2029 * Only one of the encoding bits is allowed and it
2030 * should be sufficient for the pretty print purpose (i.e. decoding).
2031 * Multiple bits can be allowed later if it is found
2032 * to be insufficient.
2033 */
2034 encoding = BTF_INT_ENCODING(int_data);
2035 if (encoding &&
2036 encoding != BTF_INT_SIGNED &&
2037 encoding != BTF_INT_CHAR &&
2038 encoding != BTF_INT_BOOL) {
2039 btf_verifier_log_type(env, t, "Unsupported encoding");
2040 return -ENOTSUPP;
2041 }
2042
2043 btf_verifier_log_type(env, t, NULL);
2044
2045 return meta_needed;
2046}
2047
2048static void btf_int_log(struct btf_verifier_env *env,
2049 const struct btf_type *t)
2050{
2051 int int_data = btf_type_int(t);
2052
2053 btf_verifier_log(env,
2054 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2055 t->size, BTF_INT_OFFSET(int_data),
2056 BTF_INT_BITS(int_data),
2057 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2058}
2059
2060static void btf_int128_print(struct btf_show *show, void *data)
2061{
2062 /* data points to a __int128 number.
2063 * Suppose
2064 * int128_num = *(__int128 *)data;
2065 * The below formulas shows what upper_num and lower_num represents:
2066 * upper_num = int128_num >> 64;
2067 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2068 */
2069 u64 upper_num, lower_num;
2070
2071#ifdef __BIG_ENDIAN_BITFIELD
2072 upper_num = *(u64 *)data;
2073 lower_num = *(u64 *)(data + 8);
2074#else
2075 upper_num = *(u64 *)(data + 8);
2076 lower_num = *(u64 *)data;
2077#endif
2078 if (upper_num == 0)
2079 btf_show_type_value(show, "0x%llx", lower_num);
2080 else
2081 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2082 lower_num);
2083}
2084
2085static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2086 u16 right_shift_bits)
2087{
2088 u64 upper_num, lower_num;
2089
2090#ifdef __BIG_ENDIAN_BITFIELD
2091 upper_num = print_num[0];
2092 lower_num = print_num[1];
2093#else
2094 upper_num = print_num[1];
2095 lower_num = print_num[0];
2096#endif
2097
2098 /* shake out un-needed bits by shift/or operations */
2099 if (left_shift_bits >= 64) {
2100 upper_num = lower_num << (left_shift_bits - 64);
2101 lower_num = 0;
2102 } else {
2103 upper_num = (upper_num << left_shift_bits) |
2104 (lower_num >> (64 - left_shift_bits));
2105 lower_num = lower_num << left_shift_bits;
2106 }
2107
2108 if (right_shift_bits >= 64) {
2109 lower_num = upper_num >> (right_shift_bits - 64);
2110 upper_num = 0;
2111 } else {
2112 lower_num = (lower_num >> right_shift_bits) |
2113 (upper_num << (64 - right_shift_bits));
2114 upper_num = upper_num >> right_shift_bits;
2115 }
2116
2117#ifdef __BIG_ENDIAN_BITFIELD
2118 print_num[0] = upper_num;
2119 print_num[1] = lower_num;
2120#else
2121 print_num[0] = lower_num;
2122 print_num[1] = upper_num;
2123#endif
2124}
2125
2126static void btf_bitfield_show(void *data, u8 bits_offset,
2127 u8 nr_bits, struct btf_show *show)
2128{
2129 u16 left_shift_bits, right_shift_bits;
2130 u8 nr_copy_bytes;
2131 u8 nr_copy_bits;
2132 u64 print_num[2] = {};
2133
2134 nr_copy_bits = nr_bits + bits_offset;
2135 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2136
2137 memcpy(print_num, data, nr_copy_bytes);
2138
2139#ifdef __BIG_ENDIAN_BITFIELD
2140 left_shift_bits = bits_offset;
2141#else
2142 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2143#endif
2144 right_shift_bits = BITS_PER_U128 - nr_bits;
2145
2146 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2147 btf_int128_print(show, print_num);
2148}
2149
2150
2151static void btf_int_bits_show(const struct btf *btf,
2152 const struct btf_type *t,
2153 void *data, u8 bits_offset,
2154 struct btf_show *show)
2155{
2156 u32 int_data = btf_type_int(t);
2157 u8 nr_bits = BTF_INT_BITS(int_data);
2158 u8 total_bits_offset;
2159
2160 /*
2161 * bits_offset is at most 7.
2162 * BTF_INT_OFFSET() cannot exceed 128 bits.
2163 */
2164 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2165 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2166 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2167 btf_bitfield_show(data, bits_offset, nr_bits, show);
2168}
2169
2170static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2171 u32 type_id, void *data, u8 bits_offset,
2172 struct btf_show *show)
2173{
2174 u32 int_data = btf_type_int(t);
2175 u8 encoding = BTF_INT_ENCODING(int_data);
2176 bool sign = encoding & BTF_INT_SIGNED;
2177 u8 nr_bits = BTF_INT_BITS(int_data);
2178 void *safe_data;
2179
2180 safe_data = btf_show_start_type(show, t, type_id, data);
2181 if (!safe_data)
2182 return;
2183
2184 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2185 BITS_PER_BYTE_MASKED(nr_bits)) {
2186 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2187 goto out;
2188 }
2189
2190 switch (nr_bits) {
2191 case 128:
2192 btf_int128_print(show, safe_data);
2193 break;
2194 case 64:
2195 if (sign)
2196 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2197 else
2198 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2199 break;
2200 case 32:
2201 if (sign)
2202 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2203 else
2204 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2205 break;
2206 case 16:
2207 if (sign)
2208 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2209 else
2210 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2211 break;
2212 case 8:
2213 if (show->state.array_encoding == BTF_INT_CHAR) {
2214 /* check for null terminator */
2215 if (show->state.array_terminated)
2216 break;
2217 if (*(char *)data == '\0') {
2218 show->state.array_terminated = 1;
2219 break;
2220 }
2221 if (isprint(*(char *)data)) {
2222 btf_show_type_value(show, "'%c'",
2223 *(char *)safe_data);
2224 break;
2225 }
2226 }
2227 if (sign)
2228 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2229 else
2230 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2231 break;
2232 default:
2233 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2234 break;
2235 }
2236out:
2237 btf_show_end_type(show);
2238}
2239
2240static const struct btf_kind_operations int_ops = {
2241 .check_meta = btf_int_check_meta,
2242 .resolve = btf_df_resolve,
2243 .check_member = btf_int_check_member,
2244 .check_kflag_member = btf_int_check_kflag_member,
2245 .log_details = btf_int_log,
2246 .show = btf_int_show,
2247};
2248
2249static int btf_modifier_check_member(struct btf_verifier_env *env,
2250 const struct btf_type *struct_type,
2251 const struct btf_member *member,
2252 const struct btf_type *member_type)
2253{
2254 const struct btf_type *resolved_type;
2255 u32 resolved_type_id = member->type;
2256 struct btf_member resolved_member;
2257 struct btf *btf = env->btf;
2258
2259 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2260 if (!resolved_type) {
2261 btf_verifier_log_member(env, struct_type, member,
2262 "Invalid member");
2263 return -EINVAL;
2264 }
2265
2266 resolved_member = *member;
2267 resolved_member.type = resolved_type_id;
2268
2269 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2270 &resolved_member,
2271 resolved_type);
2272}
2273
2274static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2275 const struct btf_type *struct_type,
2276 const struct btf_member *member,
2277 const struct btf_type *member_type)
2278{
2279 const struct btf_type *resolved_type;
2280 u32 resolved_type_id = member->type;
2281 struct btf_member resolved_member;
2282 struct btf *btf = env->btf;
2283
2284 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2285 if (!resolved_type) {
2286 btf_verifier_log_member(env, struct_type, member,
2287 "Invalid member");
2288 return -EINVAL;
2289 }
2290
2291 resolved_member = *member;
2292 resolved_member.type = resolved_type_id;
2293
2294 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2295 &resolved_member,
2296 resolved_type);
2297}
2298
2299static int btf_ptr_check_member(struct btf_verifier_env *env,
2300 const struct btf_type *struct_type,
2301 const struct btf_member *member,
2302 const struct btf_type *member_type)
2303{
2304 u32 struct_size, struct_bits_off, bytes_offset;
2305
2306 struct_size = struct_type->size;
2307 struct_bits_off = member->offset;
2308 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2309
2310 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2311 btf_verifier_log_member(env, struct_type, member,
2312 "Member is not byte aligned");
2313 return -EINVAL;
2314 }
2315
2316 if (struct_size - bytes_offset < sizeof(void *)) {
2317 btf_verifier_log_member(env, struct_type, member,
2318 "Member exceeds struct_size");
2319 return -EINVAL;
2320 }
2321
2322 return 0;
2323}
2324
2325static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2326 const struct btf_type *t,
2327 u32 meta_left)
2328{
2329 if (btf_type_vlen(t)) {
2330 btf_verifier_log_type(env, t, "vlen != 0");
2331 return -EINVAL;
2332 }
2333
2334 if (btf_type_kflag(t)) {
2335 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2336 return -EINVAL;
2337 }
2338
2339 if (!BTF_TYPE_ID_VALID(t->type)) {
2340 btf_verifier_log_type(env, t, "Invalid type_id");
2341 return -EINVAL;
2342 }
2343
2344 /* typedef type must have a valid name, and other ref types,
2345 * volatile, const, restrict, should have a null name.
2346 */
2347 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2348 if (!t->name_off ||
2349 !btf_name_valid_identifier(env->btf, t->name_off)) {
2350 btf_verifier_log_type(env, t, "Invalid name");
2351 return -EINVAL;
2352 }
2353 } else {
2354 if (t->name_off) {
2355 btf_verifier_log_type(env, t, "Invalid name");
2356 return -EINVAL;
2357 }
2358 }
2359
2360 btf_verifier_log_type(env, t, NULL);
2361
2362 return 0;
2363}
2364
2365static int btf_modifier_resolve(struct btf_verifier_env *env,
2366 const struct resolve_vertex *v)
2367{
2368 const struct btf_type *t = v->t;
2369 const struct btf_type *next_type;
2370 u32 next_type_id = t->type;
2371 struct btf *btf = env->btf;
2372
2373 next_type = btf_type_by_id(btf, next_type_id);
2374 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2375 btf_verifier_log_type(env, v->t, "Invalid type_id");
2376 return -EINVAL;
2377 }
2378
2379 if (!env_type_is_resolve_sink(env, next_type) &&
2380 !env_type_is_resolved(env, next_type_id))
2381 return env_stack_push(env, next_type, next_type_id);
2382
2383 /* Figure out the resolved next_type_id with size.
2384 * They will be stored in the current modifier's
2385 * resolved_ids and resolved_sizes such that it can
2386 * save us a few type-following when we use it later (e.g. in
2387 * pretty print).
2388 */
2389 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2390 if (env_type_is_resolved(env, next_type_id))
2391 next_type = btf_type_id_resolve(btf, &next_type_id);
2392
2393 /* "typedef void new_void", "const void"...etc */
2394 if (!btf_type_is_void(next_type) &&
2395 !btf_type_is_fwd(next_type) &&
2396 !btf_type_is_func_proto(next_type)) {
2397 btf_verifier_log_type(env, v->t, "Invalid type_id");
2398 return -EINVAL;
2399 }
2400 }
2401
2402 env_stack_pop_resolved(env, next_type_id, 0);
2403
2404 return 0;
2405}
2406
2407static int btf_var_resolve(struct btf_verifier_env *env,
2408 const struct resolve_vertex *v)
2409{
2410 const struct btf_type *next_type;
2411 const struct btf_type *t = v->t;
2412 u32 next_type_id = t->type;
2413 struct btf *btf = env->btf;
2414
2415 next_type = btf_type_by_id(btf, next_type_id);
2416 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2417 btf_verifier_log_type(env, v->t, "Invalid type_id");
2418 return -EINVAL;
2419 }
2420
2421 if (!env_type_is_resolve_sink(env, next_type) &&
2422 !env_type_is_resolved(env, next_type_id))
2423 return env_stack_push(env, next_type, next_type_id);
2424
2425 if (btf_type_is_modifier(next_type)) {
2426 const struct btf_type *resolved_type;
2427 u32 resolved_type_id;
2428
2429 resolved_type_id = next_type_id;
2430 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2431
2432 if (btf_type_is_ptr(resolved_type) &&
2433 !env_type_is_resolve_sink(env, resolved_type) &&
2434 !env_type_is_resolved(env, resolved_type_id))
2435 return env_stack_push(env, resolved_type,
2436 resolved_type_id);
2437 }
2438
2439 /* We must resolve to something concrete at this point, no
2440 * forward types or similar that would resolve to size of
2441 * zero is allowed.
2442 */
2443 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2444 btf_verifier_log_type(env, v->t, "Invalid type_id");
2445 return -EINVAL;
2446 }
2447
2448 env_stack_pop_resolved(env, next_type_id, 0);
2449
2450 return 0;
2451}
2452
2453static int btf_ptr_resolve(struct btf_verifier_env *env,
2454 const struct resolve_vertex *v)
2455{
2456 const struct btf_type *next_type;
2457 const struct btf_type *t = v->t;
2458 u32 next_type_id = t->type;
2459 struct btf *btf = env->btf;
2460
2461 next_type = btf_type_by_id(btf, next_type_id);
2462 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2463 btf_verifier_log_type(env, v->t, "Invalid type_id");
2464 return -EINVAL;
2465 }
2466
2467 if (!env_type_is_resolve_sink(env, next_type) &&
2468 !env_type_is_resolved(env, next_type_id))
2469 return env_stack_push(env, next_type, next_type_id);
2470
2471 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2472 * the modifier may have stopped resolving when it was resolved
2473 * to a ptr (last-resolved-ptr).
2474 *
2475 * We now need to continue from the last-resolved-ptr to
2476 * ensure the last-resolved-ptr will not referring back to
2477 * the currenct ptr (t).
2478 */
2479 if (btf_type_is_modifier(next_type)) {
2480 const struct btf_type *resolved_type;
2481 u32 resolved_type_id;
2482
2483 resolved_type_id = next_type_id;
2484 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2485
2486 if (btf_type_is_ptr(resolved_type) &&
2487 !env_type_is_resolve_sink(env, resolved_type) &&
2488 !env_type_is_resolved(env, resolved_type_id))
2489 return env_stack_push(env, resolved_type,
2490 resolved_type_id);
2491 }
2492
2493 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2494 if (env_type_is_resolved(env, next_type_id))
2495 next_type = btf_type_id_resolve(btf, &next_type_id);
2496
2497 if (!btf_type_is_void(next_type) &&
2498 !btf_type_is_fwd(next_type) &&
2499 !btf_type_is_func_proto(next_type)) {
2500 btf_verifier_log_type(env, v->t, "Invalid type_id");
2501 return -EINVAL;
2502 }
2503 }
2504
2505 env_stack_pop_resolved(env, next_type_id, 0);
2506
2507 return 0;
2508}
2509
2510static void btf_modifier_show(const struct btf *btf,
2511 const struct btf_type *t,
2512 u32 type_id, void *data,
2513 u8 bits_offset, struct btf_show *show)
2514{
2515 if (btf->resolved_ids)
2516 t = btf_type_id_resolve(btf, &type_id);
2517 else
2518 t = btf_type_skip_modifiers(btf, type_id, NULL);
2519
2520 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2521}
2522
2523static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2524 u32 type_id, void *data, u8 bits_offset,
2525 struct btf_show *show)
2526{
2527 t = btf_type_id_resolve(btf, &type_id);
2528
2529 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2530}
2531
2532static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2533 u32 type_id, void *data, u8 bits_offset,
2534 struct btf_show *show)
2535{
2536 void *safe_data;
2537
2538 safe_data = btf_show_start_type(show, t, type_id, data);
2539 if (!safe_data)
2540 return;
2541
2542 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2543 if (show->flags & BTF_SHOW_PTR_RAW)
2544 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2545 else
2546 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2547 btf_show_end_type(show);
2548}
2549
2550static void btf_ref_type_log(struct btf_verifier_env *env,
2551 const struct btf_type *t)
2552{
2553 btf_verifier_log(env, "type_id=%u", t->type);
2554}
2555
2556static struct btf_kind_operations modifier_ops = {
2557 .check_meta = btf_ref_type_check_meta,
2558 .resolve = btf_modifier_resolve,
2559 .check_member = btf_modifier_check_member,
2560 .check_kflag_member = btf_modifier_check_kflag_member,
2561 .log_details = btf_ref_type_log,
2562 .show = btf_modifier_show,
2563};
2564
2565static struct btf_kind_operations ptr_ops = {
2566 .check_meta = btf_ref_type_check_meta,
2567 .resolve = btf_ptr_resolve,
2568 .check_member = btf_ptr_check_member,
2569 .check_kflag_member = btf_generic_check_kflag_member,
2570 .log_details = btf_ref_type_log,
2571 .show = btf_ptr_show,
2572};
2573
2574static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2575 const struct btf_type *t,
2576 u32 meta_left)
2577{
2578 if (btf_type_vlen(t)) {
2579 btf_verifier_log_type(env, t, "vlen != 0");
2580 return -EINVAL;
2581 }
2582
2583 if (t->type) {
2584 btf_verifier_log_type(env, t, "type != 0");
2585 return -EINVAL;
2586 }
2587
2588 /* fwd type must have a valid name */
2589 if (!t->name_off ||
2590 !btf_name_valid_identifier(env->btf, t->name_off)) {
2591 btf_verifier_log_type(env, t, "Invalid name");
2592 return -EINVAL;
2593 }
2594
2595 btf_verifier_log_type(env, t, NULL);
2596
2597 return 0;
2598}
2599
2600static void btf_fwd_type_log(struct btf_verifier_env *env,
2601 const struct btf_type *t)
2602{
2603 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2604}
2605
2606static struct btf_kind_operations fwd_ops = {
2607 .check_meta = btf_fwd_check_meta,
2608 .resolve = btf_df_resolve,
2609 .check_member = btf_df_check_member,
2610 .check_kflag_member = btf_df_check_kflag_member,
2611 .log_details = btf_fwd_type_log,
2612 .show = btf_df_show,
2613};
2614
2615static int btf_array_check_member(struct btf_verifier_env *env,
2616 const struct btf_type *struct_type,
2617 const struct btf_member *member,
2618 const struct btf_type *member_type)
2619{
2620 u32 struct_bits_off = member->offset;
2621 u32 struct_size, bytes_offset;
2622 u32 array_type_id, array_size;
2623 struct btf *btf = env->btf;
2624
2625 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2626 btf_verifier_log_member(env, struct_type, member,
2627 "Member is not byte aligned");
2628 return -EINVAL;
2629 }
2630
2631 array_type_id = member->type;
2632 btf_type_id_size(btf, &array_type_id, &array_size);
2633 struct_size = struct_type->size;
2634 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2635 if (struct_size - bytes_offset < array_size) {
2636 btf_verifier_log_member(env, struct_type, member,
2637 "Member exceeds struct_size");
2638 return -EINVAL;
2639 }
2640
2641 return 0;
2642}
2643
2644static s32 btf_array_check_meta(struct btf_verifier_env *env,
2645 const struct btf_type *t,
2646 u32 meta_left)
2647{
2648 const struct btf_array *array = btf_type_array(t);
2649 u32 meta_needed = sizeof(*array);
2650
2651 if (meta_left < meta_needed) {
2652 btf_verifier_log_basic(env, t,
2653 "meta_left:%u meta_needed:%u",
2654 meta_left, meta_needed);
2655 return -EINVAL;
2656 }
2657
2658 /* array type should not have a name */
2659 if (t->name_off) {
2660 btf_verifier_log_type(env, t, "Invalid name");
2661 return -EINVAL;
2662 }
2663
2664 if (btf_type_vlen(t)) {
2665 btf_verifier_log_type(env, t, "vlen != 0");
2666 return -EINVAL;
2667 }
2668
2669 if (btf_type_kflag(t)) {
2670 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2671 return -EINVAL;
2672 }
2673
2674 if (t->size) {
2675 btf_verifier_log_type(env, t, "size != 0");
2676 return -EINVAL;
2677 }
2678
2679 /* Array elem type and index type cannot be in type void,
2680 * so !array->type and !array->index_type are not allowed.
2681 */
2682 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2683 btf_verifier_log_type(env, t, "Invalid elem");
2684 return -EINVAL;
2685 }
2686
2687 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2688 btf_verifier_log_type(env, t, "Invalid index");
2689 return -EINVAL;
2690 }
2691
2692 btf_verifier_log_type(env, t, NULL);
2693
2694 return meta_needed;
2695}
2696
2697static int btf_array_resolve(struct btf_verifier_env *env,
2698 const struct resolve_vertex *v)
2699{
2700 const struct btf_array *array = btf_type_array(v->t);
2701 const struct btf_type *elem_type, *index_type;
2702 u32 elem_type_id, index_type_id;
2703 struct btf *btf = env->btf;
2704 u32 elem_size;
2705
2706 /* Check array->index_type */
2707 index_type_id = array->index_type;
2708 index_type = btf_type_by_id(btf, index_type_id);
2709 if (btf_type_nosize_or_null(index_type) ||
2710 btf_type_is_resolve_source_only(index_type)) {
2711 btf_verifier_log_type(env, v->t, "Invalid index");
2712 return -EINVAL;
2713 }
2714
2715 if (!env_type_is_resolve_sink(env, index_type) &&
2716 !env_type_is_resolved(env, index_type_id))
2717 return env_stack_push(env, index_type, index_type_id);
2718
2719 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2720 if (!index_type || !btf_type_is_int(index_type) ||
2721 !btf_type_int_is_regular(index_type)) {
2722 btf_verifier_log_type(env, v->t, "Invalid index");
2723 return -EINVAL;
2724 }
2725
2726 /* Check array->type */
2727 elem_type_id = array->type;
2728 elem_type = btf_type_by_id(btf, elem_type_id);
2729 if (btf_type_nosize_or_null(elem_type) ||
2730 btf_type_is_resolve_source_only(elem_type)) {
2731 btf_verifier_log_type(env, v->t,
2732 "Invalid elem");
2733 return -EINVAL;
2734 }
2735
2736 if (!env_type_is_resolve_sink(env, elem_type) &&
2737 !env_type_is_resolved(env, elem_type_id))
2738 return env_stack_push(env, elem_type, elem_type_id);
2739
2740 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2741 if (!elem_type) {
2742 btf_verifier_log_type(env, v->t, "Invalid elem");
2743 return -EINVAL;
2744 }
2745
2746 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2747 btf_verifier_log_type(env, v->t, "Invalid array of int");
2748 return -EINVAL;
2749 }
2750
2751 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2752 btf_verifier_log_type(env, v->t,
2753 "Array size overflows U32_MAX");
2754 return -EINVAL;
2755 }
2756
2757 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2758
2759 return 0;
2760}
2761
2762static void btf_array_log(struct btf_verifier_env *env,
2763 const struct btf_type *t)
2764{
2765 const struct btf_array *array = btf_type_array(t);
2766
2767 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2768 array->type, array->index_type, array->nelems);
2769}
2770
2771static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2772 u32 type_id, void *data, u8 bits_offset,
2773 struct btf_show *show)
2774{
2775 const struct btf_array *array = btf_type_array(t);
2776 const struct btf_kind_operations *elem_ops;
2777 const struct btf_type *elem_type;
2778 u32 i, elem_size = 0, elem_type_id;
2779 u16 encoding = 0;
2780
2781 elem_type_id = array->type;
2782 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2783 if (elem_type && btf_type_has_size(elem_type))
2784 elem_size = elem_type->size;
2785
2786 if (elem_type && btf_type_is_int(elem_type)) {
2787 u32 int_type = btf_type_int(elem_type);
2788
2789 encoding = BTF_INT_ENCODING(int_type);
2790
2791 /*
2792 * BTF_INT_CHAR encoding never seems to be set for
2793 * char arrays, so if size is 1 and element is
2794 * printable as a char, we'll do that.
2795 */
2796 if (elem_size == 1)
2797 encoding = BTF_INT_CHAR;
2798 }
2799
2800 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2801 return;
2802
2803 if (!elem_type)
2804 goto out;
2805 elem_ops = btf_type_ops(elem_type);
2806
2807 for (i = 0; i < array->nelems; i++) {
2808
2809 btf_show_start_array_member(show);
2810
2811 elem_ops->show(btf, elem_type, elem_type_id, data,
2812 bits_offset, show);
2813 data += elem_size;
2814
2815 btf_show_end_array_member(show);
2816
2817 if (show->state.array_terminated)
2818 break;
2819 }
2820out:
2821 btf_show_end_array_type(show);
2822}
2823
2824static void btf_array_show(const struct btf *btf, const struct btf_type *t,
2825 u32 type_id, void *data, u8 bits_offset,
2826 struct btf_show *show)
2827{
2828 const struct btf_member *m = show->state.member;
2829
2830 /*
2831 * First check if any members would be shown (are non-zero).
2832 * See comments above "struct btf_show" definition for more
2833 * details on how this works at a high-level.
2834 */
2835 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
2836 if (!show->state.depth_check) {
2837 show->state.depth_check = show->state.depth + 1;
2838 show->state.depth_to_show = 0;
2839 }
2840 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2841 show->state.member = m;
2842
2843 if (show->state.depth_check != show->state.depth + 1)
2844 return;
2845 show->state.depth_check = 0;
2846
2847 if (show->state.depth_to_show <= show->state.depth)
2848 return;
2849 /*
2850 * Reaching here indicates we have recursed and found
2851 * non-zero array member(s).
2852 */
2853 }
2854 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2855}
2856
2857static struct btf_kind_operations array_ops = {
2858 .check_meta = btf_array_check_meta,
2859 .resolve = btf_array_resolve,
2860 .check_member = btf_array_check_member,
2861 .check_kflag_member = btf_generic_check_kflag_member,
2862 .log_details = btf_array_log,
2863 .show = btf_array_show,
2864};
2865
2866static int btf_struct_check_member(struct btf_verifier_env *env,
2867 const struct btf_type *struct_type,
2868 const struct btf_member *member,
2869 const struct btf_type *member_type)
2870{
2871 u32 struct_bits_off = member->offset;
2872 u32 struct_size, bytes_offset;
2873
2874 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2875 btf_verifier_log_member(env, struct_type, member,
2876 "Member is not byte aligned");
2877 return -EINVAL;
2878 }
2879
2880 struct_size = struct_type->size;
2881 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2882 if (struct_size - bytes_offset < member_type->size) {
2883 btf_verifier_log_member(env, struct_type, member,
2884 "Member exceeds struct_size");
2885 return -EINVAL;
2886 }
2887
2888 return 0;
2889}
2890
2891static s32 btf_struct_check_meta(struct btf_verifier_env *env,
2892 const struct btf_type *t,
2893 u32 meta_left)
2894{
2895 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
2896 const struct btf_member *member;
2897 u32 meta_needed, last_offset;
2898 struct btf *btf = env->btf;
2899 u32 struct_size = t->size;
2900 u32 offset;
2901 u16 i;
2902
2903 meta_needed = btf_type_vlen(t) * sizeof(*member);
2904 if (meta_left < meta_needed) {
2905 btf_verifier_log_basic(env, t,
2906 "meta_left:%u meta_needed:%u",
2907 meta_left, meta_needed);
2908 return -EINVAL;
2909 }
2910
2911 /* struct type either no name or a valid one */
2912 if (t->name_off &&
2913 !btf_name_valid_identifier(env->btf, t->name_off)) {
2914 btf_verifier_log_type(env, t, "Invalid name");
2915 return -EINVAL;
2916 }
2917
2918 btf_verifier_log_type(env, t, NULL);
2919
2920 last_offset = 0;
2921 for_each_member(i, t, member) {
2922 if (!btf_name_offset_valid(btf, member->name_off)) {
2923 btf_verifier_log_member(env, t, member,
2924 "Invalid member name_offset:%u",
2925 member->name_off);
2926 return -EINVAL;
2927 }
2928
2929 /* struct member either no name or a valid one */
2930 if (member->name_off &&
2931 !btf_name_valid_identifier(btf, member->name_off)) {
2932 btf_verifier_log_member(env, t, member, "Invalid name");
2933 return -EINVAL;
2934 }
2935 /* A member cannot be in type void */
2936 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
2937 btf_verifier_log_member(env, t, member,
2938 "Invalid type_id");
2939 return -EINVAL;
2940 }
2941
2942 offset = btf_member_bit_offset(t, member);
2943 if (is_union && offset) {
2944 btf_verifier_log_member(env, t, member,
2945 "Invalid member bits_offset");
2946 return -EINVAL;
2947 }
2948
2949 /*
2950 * ">" instead of ">=" because the last member could be
2951 * "char a[0];"
2952 */
2953 if (last_offset > offset) {
2954 btf_verifier_log_member(env, t, member,
2955 "Invalid member bits_offset");
2956 return -EINVAL;
2957 }
2958
2959 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
2960 btf_verifier_log_member(env, t, member,
2961 "Member bits_offset exceeds its struct size");
2962 return -EINVAL;
2963 }
2964
2965 btf_verifier_log_member(env, t, member, NULL);
2966 last_offset = offset;
2967 }
2968
2969 return meta_needed;
2970}
2971
2972static int btf_struct_resolve(struct btf_verifier_env *env,
2973 const struct resolve_vertex *v)
2974{
2975 const struct btf_member *member;
2976 int err;
2977 u16 i;
2978
2979 /* Before continue resolving the next_member,
2980 * ensure the last member is indeed resolved to a
2981 * type with size info.
2982 */
2983 if (v->next_member) {
2984 const struct btf_type *last_member_type;
2985 const struct btf_member *last_member;
2986 u16 last_member_type_id;
2987
2988 last_member = btf_type_member(v->t) + v->next_member - 1;
2989 last_member_type_id = last_member->type;
2990 if (WARN_ON_ONCE(!env_type_is_resolved(env,
2991 last_member_type_id)))
2992 return -EINVAL;
2993
2994 last_member_type = btf_type_by_id(env->btf,
2995 last_member_type_id);
2996 if (btf_type_kflag(v->t))
2997 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
2998 last_member,
2999 last_member_type);
3000 else
3001 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3002 last_member,
3003 last_member_type);
3004 if (err)
3005 return err;
3006 }
3007
3008 for_each_member_from(i, v->next_member, v->t, member) {
3009 u32 member_type_id = member->type;
3010 const struct btf_type *member_type = btf_type_by_id(env->btf,
3011 member_type_id);
3012
3013 if (btf_type_nosize_or_null(member_type) ||
3014 btf_type_is_resolve_source_only(member_type)) {
3015 btf_verifier_log_member(env, v->t, member,
3016 "Invalid member");
3017 return -EINVAL;
3018 }
3019
3020 if (!env_type_is_resolve_sink(env, member_type) &&
3021 !env_type_is_resolved(env, member_type_id)) {
3022 env_stack_set_next_member(env, i + 1);
3023 return env_stack_push(env, member_type, member_type_id);
3024 }
3025
3026 if (btf_type_kflag(v->t))
3027 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3028 member,
3029 member_type);
3030 else
3031 err = btf_type_ops(member_type)->check_member(env, v->t,
3032 member,
3033 member_type);
3034 if (err)
3035 return err;
3036 }
3037
3038 env_stack_pop_resolved(env, 0, 0);
3039
3040 return 0;
3041}
3042
3043static void btf_struct_log(struct btf_verifier_env *env,
3044 const struct btf_type *t)
3045{
3046 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3047}
3048
3049/* find 'struct bpf_spin_lock' in map value.
3050 * return >= 0 offset if found
3051 * and < 0 in case of error
3052 */
3053int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
3054{
3055 const struct btf_member *member;
3056 u32 i, off = -ENOENT;
3057
3058 if (!__btf_type_is_struct(t))
3059 return -EINVAL;
3060
3061 for_each_member(i, t, member) {
3062 const struct btf_type *member_type = btf_type_by_id(btf,
3063 member->type);
3064 if (!__btf_type_is_struct(member_type))
3065 continue;
3066 if (member_type->size != sizeof(struct bpf_spin_lock))
3067 continue;
3068 if (strcmp(__btf_name_by_offset(btf, member_type->name_off),
3069 "bpf_spin_lock"))
3070 continue;
3071 if (off != -ENOENT)
3072 /* only one 'struct bpf_spin_lock' is allowed */
3073 return -E2BIG;
3074 off = btf_member_bit_offset(t, member);
3075 if (off % 8)
3076 /* valid C code cannot generate such BTF */
3077 return -EINVAL;
3078 off /= 8;
3079 if (off % __alignof__(struct bpf_spin_lock))
3080 /* valid struct bpf_spin_lock will be 4 byte aligned */
3081 return -EINVAL;
3082 }
3083 return off;
3084}
3085
3086static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3087 u32 type_id, void *data, u8 bits_offset,
3088 struct btf_show *show)
3089{
3090 const struct btf_member *member;
3091 void *safe_data;
3092 u32 i;
3093
3094 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3095 if (!safe_data)
3096 return;
3097
3098 for_each_member(i, t, member) {
3099 const struct btf_type *member_type = btf_type_by_id(btf,
3100 member->type);
3101 const struct btf_kind_operations *ops;
3102 u32 member_offset, bitfield_size;
3103 u32 bytes_offset;
3104 u8 bits8_offset;
3105
3106 btf_show_start_member(show, member);
3107
3108 member_offset = btf_member_bit_offset(t, member);
3109 bitfield_size = btf_member_bitfield_size(t, member);
3110 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3111 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3112 if (bitfield_size) {
3113 safe_data = btf_show_start_type(show, member_type,
3114 member->type,
3115 data + bytes_offset);
3116 if (safe_data)
3117 btf_bitfield_show(safe_data,
3118 bits8_offset,
3119 bitfield_size, show);
3120 btf_show_end_type(show);
3121 } else {
3122 ops = btf_type_ops(member_type);
3123 ops->show(btf, member_type, member->type,
3124 data + bytes_offset, bits8_offset, show);
3125 }
3126
3127 btf_show_end_member(show);
3128 }
3129
3130 btf_show_end_struct_type(show);
3131}
3132
3133static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3134 u32 type_id, void *data, u8 bits_offset,
3135 struct btf_show *show)
3136{
3137 const struct btf_member *m = show->state.member;
3138
3139 /*
3140 * First check if any members would be shown (are non-zero).
3141 * See comments above "struct btf_show" definition for more
3142 * details on how this works at a high-level.
3143 */
3144 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3145 if (!show->state.depth_check) {
3146 show->state.depth_check = show->state.depth + 1;
3147 show->state.depth_to_show = 0;
3148 }
3149 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3150 /* Restore saved member data here */
3151 show->state.member = m;
3152 if (show->state.depth_check != show->state.depth + 1)
3153 return;
3154 show->state.depth_check = 0;
3155
3156 if (show->state.depth_to_show <= show->state.depth)
3157 return;
3158 /*
3159 * Reaching here indicates we have recursed and found
3160 * non-zero child values.
3161 */
3162 }
3163
3164 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3165}
3166
3167static struct btf_kind_operations struct_ops = {
3168 .check_meta = btf_struct_check_meta,
3169 .resolve = btf_struct_resolve,
3170 .check_member = btf_struct_check_member,
3171 .check_kflag_member = btf_generic_check_kflag_member,
3172 .log_details = btf_struct_log,
3173 .show = btf_struct_show,
3174};
3175
3176static int btf_enum_check_member(struct btf_verifier_env *env,
3177 const struct btf_type *struct_type,
3178 const struct btf_member *member,
3179 const struct btf_type *member_type)
3180{
3181 u32 struct_bits_off = member->offset;
3182 u32 struct_size, bytes_offset;
3183
3184 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3185 btf_verifier_log_member(env, struct_type, member,
3186 "Member is not byte aligned");
3187 return -EINVAL;
3188 }
3189
3190 struct_size = struct_type->size;
3191 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3192 if (struct_size - bytes_offset < member_type->size) {
3193 btf_verifier_log_member(env, struct_type, member,
3194 "Member exceeds struct_size");
3195 return -EINVAL;
3196 }
3197
3198 return 0;
3199}
3200
3201static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
3202 const struct btf_type *struct_type,
3203 const struct btf_member *member,
3204 const struct btf_type *member_type)
3205{
3206 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
3207 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
3208
3209 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
3210 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
3211 if (!nr_bits) {
3212 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3213 btf_verifier_log_member(env, struct_type, member,
3214 "Member is not byte aligned");
3215 return -EINVAL;
3216 }
3217
3218 nr_bits = int_bitsize;
3219 } else if (nr_bits > int_bitsize) {
3220 btf_verifier_log_member(env, struct_type, member,
3221 "Invalid member bitfield_size");
3222 return -EINVAL;
3223 }
3224
3225 struct_size = struct_type->size;
3226 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
3227 if (struct_size < bytes_end) {
3228 btf_verifier_log_member(env, struct_type, member,
3229 "Member exceeds struct_size");
3230 return -EINVAL;
3231 }
3232
3233 return 0;
3234}
3235
3236static s32 btf_enum_check_meta(struct btf_verifier_env *env,
3237 const struct btf_type *t,
3238 u32 meta_left)
3239{
3240 const struct btf_enum *enums = btf_type_enum(t);
3241 struct btf *btf = env->btf;
3242 u16 i, nr_enums;
3243 u32 meta_needed;
3244
3245 nr_enums = btf_type_vlen(t);
3246 meta_needed = nr_enums * sizeof(*enums);
3247
3248 if (meta_left < meta_needed) {
3249 btf_verifier_log_basic(env, t,
3250 "meta_left:%u meta_needed:%u",
3251 meta_left, meta_needed);
3252 return -EINVAL;
3253 }
3254
3255 if (btf_type_kflag(t)) {
3256 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3257 return -EINVAL;
3258 }
3259
3260 if (t->size > 8 || !is_power_of_2(t->size)) {
3261 btf_verifier_log_type(env, t, "Unexpected size");
3262 return -EINVAL;
3263 }
3264
3265 /* enum type either no name or a valid one */
3266 if (t->name_off &&
3267 !btf_name_valid_identifier(env->btf, t->name_off)) {
3268 btf_verifier_log_type(env, t, "Invalid name");
3269 return -EINVAL;
3270 }
3271
3272 btf_verifier_log_type(env, t, NULL);
3273
3274 for (i = 0; i < nr_enums; i++) {
3275 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
3276 btf_verifier_log(env, "\tInvalid name_offset:%u",
3277 enums[i].name_off);
3278 return -EINVAL;
3279 }
3280
3281 /* enum member must have a valid name */
3282 if (!enums[i].name_off ||
3283 !btf_name_valid_identifier(btf, enums[i].name_off)) {
3284 btf_verifier_log_type(env, t, "Invalid name");
3285 return -EINVAL;
3286 }
3287
3288 if (env->log.level == BPF_LOG_KERNEL)
3289 continue;
3290 btf_verifier_log(env, "\t%s val=%d\n",
3291 __btf_name_by_offset(btf, enums[i].name_off),
3292 enums[i].val);
3293 }
3294
3295 return meta_needed;
3296}
3297
3298static void btf_enum_log(struct btf_verifier_env *env,
3299 const struct btf_type *t)
3300{
3301 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3302}
3303
3304static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
3305 u32 type_id, void *data, u8 bits_offset,
3306 struct btf_show *show)
3307{
3308 const struct btf_enum *enums = btf_type_enum(t);
3309 u32 i, nr_enums = btf_type_vlen(t);
3310 void *safe_data;
3311 int v;
3312
3313 safe_data = btf_show_start_type(show, t, type_id, data);
3314 if (!safe_data)
3315 return;
3316
3317 v = *(int *)safe_data;
3318
3319 for (i = 0; i < nr_enums; i++) {
3320 if (v != enums[i].val)
3321 continue;
3322
3323 btf_show_type_value(show, "%s",
3324 __btf_name_by_offset(btf,
3325 enums[i].name_off));
3326
3327 btf_show_end_type(show);
3328 return;
3329 }
3330
3331 btf_show_type_value(show, "%d", v);
3332 btf_show_end_type(show);
3333}
3334
3335static struct btf_kind_operations enum_ops = {
3336 .check_meta = btf_enum_check_meta,
3337 .resolve = btf_df_resolve,
3338 .check_member = btf_enum_check_member,
3339 .check_kflag_member = btf_enum_check_kflag_member,
3340 .log_details = btf_enum_log,
3341 .show = btf_enum_show,
3342};
3343
3344static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
3345 const struct btf_type *t,
3346 u32 meta_left)
3347{
3348 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
3349
3350 if (meta_left < meta_needed) {
3351 btf_verifier_log_basic(env, t,
3352 "meta_left:%u meta_needed:%u",
3353 meta_left, meta_needed);
3354 return -EINVAL;
3355 }
3356
3357 if (t->name_off) {
3358 btf_verifier_log_type(env, t, "Invalid name");
3359 return -EINVAL;
3360 }
3361
3362 if (btf_type_kflag(t)) {
3363 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3364 return -EINVAL;
3365 }
3366
3367 btf_verifier_log_type(env, t, NULL);
3368
3369 return meta_needed;
3370}
3371
3372static void btf_func_proto_log(struct btf_verifier_env *env,
3373 const struct btf_type *t)
3374{
3375 const struct btf_param *args = (const struct btf_param *)(t + 1);
3376 u16 nr_args = btf_type_vlen(t), i;
3377
3378 btf_verifier_log(env, "return=%u args=(", t->type);
3379 if (!nr_args) {
3380 btf_verifier_log(env, "void");
3381 goto done;
3382 }
3383
3384 if (nr_args == 1 && !args[0].type) {
3385 /* Only one vararg */
3386 btf_verifier_log(env, "vararg");
3387 goto done;
3388 }
3389
3390 btf_verifier_log(env, "%u %s", args[0].type,
3391 __btf_name_by_offset(env->btf,
3392 args[0].name_off));
3393 for (i = 1; i < nr_args - 1; i++)
3394 btf_verifier_log(env, ", %u %s", args[i].type,
3395 __btf_name_by_offset(env->btf,
3396 args[i].name_off));
3397
3398 if (nr_args > 1) {
3399 const struct btf_param *last_arg = &args[nr_args - 1];
3400
3401 if (last_arg->type)
3402 btf_verifier_log(env, ", %u %s", last_arg->type,
3403 __btf_name_by_offset(env->btf,
3404 last_arg->name_off));
3405 else
3406 btf_verifier_log(env, ", vararg");
3407 }
3408
3409done:
3410 btf_verifier_log(env, ")");
3411}
3412
3413static struct btf_kind_operations func_proto_ops = {
3414 .check_meta = btf_func_proto_check_meta,
3415 .resolve = btf_df_resolve,
3416 /*
3417 * BTF_KIND_FUNC_PROTO cannot be directly referred by
3418 * a struct's member.
3419 *
3420 * It should be a function pointer instead.
3421 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
3422 *
3423 * Hence, there is no btf_func_check_member().
3424 */
3425 .check_member = btf_df_check_member,
3426 .check_kflag_member = btf_df_check_kflag_member,
3427 .log_details = btf_func_proto_log,
3428 .show = btf_df_show,
3429};
3430
3431static s32 btf_func_check_meta(struct btf_verifier_env *env,
3432 const struct btf_type *t,
3433 u32 meta_left)
3434{
3435 if (!t->name_off ||
3436 !btf_name_valid_identifier(env->btf, t->name_off)) {
3437 btf_verifier_log_type(env, t, "Invalid name");
3438 return -EINVAL;
3439 }
3440
3441 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
3442 btf_verifier_log_type(env, t, "Invalid func linkage");
3443 return -EINVAL;
3444 }
3445
3446 if (btf_type_kflag(t)) {
3447 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3448 return -EINVAL;
3449 }
3450
3451 btf_verifier_log_type(env, t, NULL);
3452
3453 return 0;
3454}
3455
3456static struct btf_kind_operations func_ops = {
3457 .check_meta = btf_func_check_meta,
3458 .resolve = btf_df_resolve,
3459 .check_member = btf_df_check_member,
3460 .check_kflag_member = btf_df_check_kflag_member,
3461 .log_details = btf_ref_type_log,
3462 .show = btf_df_show,
3463};
3464
3465static s32 btf_var_check_meta(struct btf_verifier_env *env,
3466 const struct btf_type *t,
3467 u32 meta_left)
3468{
3469 const struct btf_var *var;
3470 u32 meta_needed = sizeof(*var);
3471
3472 if (meta_left < meta_needed) {
3473 btf_verifier_log_basic(env, t,
3474 "meta_left:%u meta_needed:%u",
3475 meta_left, meta_needed);
3476 return -EINVAL;
3477 }
3478
3479 if (btf_type_vlen(t)) {
3480 btf_verifier_log_type(env, t, "vlen != 0");
3481 return -EINVAL;
3482 }
3483
3484 if (btf_type_kflag(t)) {
3485 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3486 return -EINVAL;
3487 }
3488
3489 if (!t->name_off ||
3490 !__btf_name_valid(env->btf, t->name_off, true)) {
3491 btf_verifier_log_type(env, t, "Invalid name");
3492 return -EINVAL;
3493 }
3494
3495 /* A var cannot be in type void */
3496 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
3497 btf_verifier_log_type(env, t, "Invalid type_id");
3498 return -EINVAL;
3499 }
3500
3501 var = btf_type_var(t);
3502 if (var->linkage != BTF_VAR_STATIC &&
3503 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
3504 btf_verifier_log_type(env, t, "Linkage not supported");
3505 return -EINVAL;
3506 }
3507
3508 btf_verifier_log_type(env, t, NULL);
3509
3510 return meta_needed;
3511}
3512
3513static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
3514{
3515 const struct btf_var *var = btf_type_var(t);
3516
3517 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
3518}
3519
3520static const struct btf_kind_operations var_ops = {
3521 .check_meta = btf_var_check_meta,
3522 .resolve = btf_var_resolve,
3523 .check_member = btf_df_check_member,
3524 .check_kflag_member = btf_df_check_kflag_member,
3525 .log_details = btf_var_log,
3526 .show = btf_var_show,
3527};
3528
3529static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
3530 const struct btf_type *t,
3531 u32 meta_left)
3532{
3533 const struct btf_var_secinfo *vsi;
3534 u64 last_vsi_end_off = 0, sum = 0;
3535 u32 i, meta_needed;
3536
3537 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
3538 if (meta_left < meta_needed) {
3539 btf_verifier_log_basic(env, t,
3540 "meta_left:%u meta_needed:%u",
3541 meta_left, meta_needed);
3542 return -EINVAL;
3543 }
3544
3545 if (!t->size) {
3546 btf_verifier_log_type(env, t, "size == 0");
3547 return -EINVAL;
3548 }
3549
3550 if (btf_type_kflag(t)) {
3551 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3552 return -EINVAL;
3553 }
3554
3555 if (!t->name_off ||
3556 !btf_name_valid_section(env->btf, t->name_off)) {
3557 btf_verifier_log_type(env, t, "Invalid name");
3558 return -EINVAL;
3559 }
3560
3561 btf_verifier_log_type(env, t, NULL);
3562
3563 for_each_vsi(i, t, vsi) {
3564 /* A var cannot be in type void */
3565 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
3566 btf_verifier_log_vsi(env, t, vsi,
3567 "Invalid type_id");
3568 return -EINVAL;
3569 }
3570
3571 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
3572 btf_verifier_log_vsi(env, t, vsi,
3573 "Invalid offset");
3574 return -EINVAL;
3575 }
3576
3577 if (!vsi->size || vsi->size > t->size) {
3578 btf_verifier_log_vsi(env, t, vsi,
3579 "Invalid size");
3580 return -EINVAL;
3581 }
3582
3583 last_vsi_end_off = vsi->offset + vsi->size;
3584 if (last_vsi_end_off > t->size) {
3585 btf_verifier_log_vsi(env, t, vsi,
3586 "Invalid offset+size");
3587 return -EINVAL;
3588 }
3589
3590 btf_verifier_log_vsi(env, t, vsi, NULL);
3591 sum += vsi->size;
3592 }
3593
3594 if (t->size < sum) {
3595 btf_verifier_log_type(env, t, "Invalid btf_info size");
3596 return -EINVAL;
3597 }
3598
3599 return meta_needed;
3600}
3601
3602static int btf_datasec_resolve(struct btf_verifier_env *env,
3603 const struct resolve_vertex *v)
3604{
3605 const struct btf_var_secinfo *vsi;
3606 struct btf *btf = env->btf;
3607 u16 i;
3608
3609 for_each_vsi_from(i, v->next_member, v->t, vsi) {
3610 u32 var_type_id = vsi->type, type_id, type_size = 0;
3611 const struct btf_type *var_type = btf_type_by_id(env->btf,
3612 var_type_id);
3613 if (!var_type || !btf_type_is_var(var_type)) {
3614 btf_verifier_log_vsi(env, v->t, vsi,
3615 "Not a VAR kind member");
3616 return -EINVAL;
3617 }
3618
3619 if (!env_type_is_resolve_sink(env, var_type) &&
3620 !env_type_is_resolved(env, var_type_id)) {
3621 env_stack_set_next_member(env, i + 1);
3622 return env_stack_push(env, var_type, var_type_id);
3623 }
3624
3625 type_id = var_type->type;
3626 if (!btf_type_id_size(btf, &type_id, &type_size)) {
3627 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
3628 return -EINVAL;
3629 }
3630
3631 if (vsi->size < type_size) {
3632 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
3633 return -EINVAL;
3634 }
3635 }
3636
3637 env_stack_pop_resolved(env, 0, 0);
3638 return 0;
3639}
3640
3641static void btf_datasec_log(struct btf_verifier_env *env,
3642 const struct btf_type *t)
3643{
3644 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3645}
3646
3647static void btf_datasec_show(const struct btf *btf,
3648 const struct btf_type *t, u32 type_id,
3649 void *data, u8 bits_offset,
3650 struct btf_show *show)
3651{
3652 const struct btf_var_secinfo *vsi;
3653 const struct btf_type *var;
3654 u32 i;
3655
3656 if (!btf_show_start_type(show, t, type_id, data))
3657 return;
3658
3659 btf_show_type_value(show, "section (\"%s\") = {",
3660 __btf_name_by_offset(btf, t->name_off));
3661 for_each_vsi(i, t, vsi) {
3662 var = btf_type_by_id(btf, vsi->type);
3663 if (i)
3664 btf_show(show, ",");
3665 btf_type_ops(var)->show(btf, var, vsi->type,
3666 data + vsi->offset, bits_offset, show);
3667 }
3668 btf_show_end_type(show);
3669}
3670
3671static const struct btf_kind_operations datasec_ops = {
3672 .check_meta = btf_datasec_check_meta,
3673 .resolve = btf_datasec_resolve,
3674 .check_member = btf_df_check_member,
3675 .check_kflag_member = btf_df_check_kflag_member,
3676 .log_details = btf_datasec_log,
3677 .show = btf_datasec_show,
3678};
3679
3680static s32 btf_float_check_meta(struct btf_verifier_env *env,
3681 const struct btf_type *t,
3682 u32 meta_left)
3683{
3684 if (btf_type_vlen(t)) {
3685 btf_verifier_log_type(env, t, "vlen != 0");
3686 return -EINVAL;
3687 }
3688
3689 if (btf_type_kflag(t)) {
3690 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3691 return -EINVAL;
3692 }
3693
3694 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
3695 t->size != 16) {
3696 btf_verifier_log_type(env, t, "Invalid type_size");
3697 return -EINVAL;
3698 }
3699
3700 btf_verifier_log_type(env, t, NULL);
3701
3702 return 0;
3703}
3704
3705static int btf_float_check_member(struct btf_verifier_env *env,
3706 const struct btf_type *struct_type,
3707 const struct btf_member *member,
3708 const struct btf_type *member_type)
3709{
3710 u64 start_offset_bytes;
3711 u64 end_offset_bytes;
3712 u64 misalign_bits;
3713 u64 align_bytes;
3714 u64 align_bits;
3715
3716 /* Different architectures have different alignment requirements, so
3717 * here we check only for the reasonable minimum. This way we ensure
3718 * that types after CO-RE can pass the kernel BTF verifier.
3719 */
3720 align_bytes = min_t(u64, sizeof(void *), member_type->size);
3721 align_bits = align_bytes * BITS_PER_BYTE;
3722 div64_u64_rem(member->offset, align_bits, &misalign_bits);
3723 if (misalign_bits) {
3724 btf_verifier_log_member(env, struct_type, member,
3725 "Member is not properly aligned");
3726 return -EINVAL;
3727 }
3728
3729 start_offset_bytes = member->offset / BITS_PER_BYTE;
3730 end_offset_bytes = start_offset_bytes + member_type->size;
3731 if (end_offset_bytes > struct_type->size) {
3732 btf_verifier_log_member(env, struct_type, member,
3733 "Member exceeds struct_size");
3734 return -EINVAL;
3735 }
3736
3737 return 0;
3738}
3739
3740static void btf_float_log(struct btf_verifier_env *env,
3741 const struct btf_type *t)
3742{
3743 btf_verifier_log(env, "size=%u", t->size);
3744}
3745
3746static const struct btf_kind_operations float_ops = {
3747 .check_meta = btf_float_check_meta,
3748 .resolve = btf_df_resolve,
3749 .check_member = btf_float_check_member,
3750 .check_kflag_member = btf_generic_check_kflag_member,
3751 .log_details = btf_float_log,
3752 .show = btf_df_show,
3753};
3754
3755static int btf_func_proto_check(struct btf_verifier_env *env,
3756 const struct btf_type *t)
3757{
3758 const struct btf_type *ret_type;
3759 const struct btf_param *args;
3760 const struct btf *btf;
3761 u16 nr_args, i;
3762 int err;
3763
3764 btf = env->btf;
3765 args = (const struct btf_param *)(t + 1);
3766 nr_args = btf_type_vlen(t);
3767
3768 /* Check func return type which could be "void" (t->type == 0) */
3769 if (t->type) {
3770 u32 ret_type_id = t->type;
3771
3772 ret_type = btf_type_by_id(btf, ret_type_id);
3773 if (!ret_type) {
3774 btf_verifier_log_type(env, t, "Invalid return type");
3775 return -EINVAL;
3776 }
3777
3778 if (btf_type_needs_resolve(ret_type) &&
3779 !env_type_is_resolved(env, ret_type_id)) {
3780 err = btf_resolve(env, ret_type, ret_type_id);
3781 if (err)
3782 return err;
3783 }
3784
3785 /* Ensure the return type is a type that has a size */
3786 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
3787 btf_verifier_log_type(env, t, "Invalid return type");
3788 return -EINVAL;
3789 }
3790 }
3791
3792 if (!nr_args)
3793 return 0;
3794
3795 /* Last func arg type_id could be 0 if it is a vararg */
3796 if (!args[nr_args - 1].type) {
3797 if (args[nr_args - 1].name_off) {
3798 btf_verifier_log_type(env, t, "Invalid arg#%u",
3799 nr_args);
3800 return -EINVAL;
3801 }
3802 nr_args--;
3803 }
3804
3805 err = 0;
3806 for (i = 0; i < nr_args; i++) {
3807 const struct btf_type *arg_type;
3808 u32 arg_type_id;
3809
3810 arg_type_id = args[i].type;
3811 arg_type = btf_type_by_id(btf, arg_type_id);
3812 if (!arg_type) {
3813 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
3814 err = -EINVAL;
3815 break;
3816 }
3817
3818 if (args[i].name_off &&
3819 (!btf_name_offset_valid(btf, args[i].name_off) ||
3820 !btf_name_valid_identifier(btf, args[i].name_off))) {
3821 btf_verifier_log_type(env, t,
3822 "Invalid arg#%u", i + 1);
3823 err = -EINVAL;
3824 break;
3825 }
3826
3827 if (btf_type_needs_resolve(arg_type) &&
3828 !env_type_is_resolved(env, arg_type_id)) {
3829 err = btf_resolve(env, arg_type, arg_type_id);
3830 if (err)
3831 break;
3832 }
3833
3834 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
3835 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
3836 err = -EINVAL;
3837 break;
3838 }
3839 }
3840
3841 return err;
3842}
3843
3844static int btf_func_check(struct btf_verifier_env *env,
3845 const struct btf_type *t)
3846{
3847 const struct btf_type *proto_type;
3848 const struct btf_param *args;
3849 const struct btf *btf;
3850 u16 nr_args, i;
3851
3852 btf = env->btf;
3853 proto_type = btf_type_by_id(btf, t->type);
3854
3855 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
3856 btf_verifier_log_type(env, t, "Invalid type_id");
3857 return -EINVAL;
3858 }
3859
3860 args = (const struct btf_param *)(proto_type + 1);
3861 nr_args = btf_type_vlen(proto_type);
3862 for (i = 0; i < nr_args; i++) {
3863 if (!args[i].name_off && args[i].type) {
3864 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
3865 return -EINVAL;
3866 }
3867 }
3868
3869 return 0;
3870}
3871
3872static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
3873 [BTF_KIND_INT] = &int_ops,
3874 [BTF_KIND_PTR] = &ptr_ops,
3875 [BTF_KIND_ARRAY] = &array_ops,
3876 [BTF_KIND_STRUCT] = &struct_ops,
3877 [BTF_KIND_UNION] = &struct_ops,
3878 [BTF_KIND_ENUM] = &enum_ops,
3879 [BTF_KIND_FWD] = &fwd_ops,
3880 [BTF_KIND_TYPEDEF] = &modifier_ops,
3881 [BTF_KIND_VOLATILE] = &modifier_ops,
3882 [BTF_KIND_CONST] = &modifier_ops,
3883 [BTF_KIND_RESTRICT] = &modifier_ops,
3884 [BTF_KIND_FUNC] = &func_ops,
3885 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
3886 [BTF_KIND_VAR] = &var_ops,
3887 [BTF_KIND_DATASEC] = &datasec_ops,
3888 [BTF_KIND_FLOAT] = &float_ops,
3889};
3890
3891static s32 btf_check_meta(struct btf_verifier_env *env,
3892 const struct btf_type *t,
3893 u32 meta_left)
3894{
3895 u32 saved_meta_left = meta_left;
3896 s32 var_meta_size;
3897
3898 if (meta_left < sizeof(*t)) {
3899 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
3900 env->log_type_id, meta_left, sizeof(*t));
3901 return -EINVAL;
3902 }
3903 meta_left -= sizeof(*t);
3904
3905 if (t->info & ~BTF_INFO_MASK) {
3906 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
3907 env->log_type_id, t->info);
3908 return -EINVAL;
3909 }
3910
3911 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
3912 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
3913 btf_verifier_log(env, "[%u] Invalid kind:%u",
3914 env->log_type_id, BTF_INFO_KIND(t->info));
3915 return -EINVAL;
3916 }
3917
3918 if (!btf_name_offset_valid(env->btf, t->name_off)) {
3919 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
3920 env->log_type_id, t->name_off);
3921 return -EINVAL;
3922 }
3923
3924 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
3925 if (var_meta_size < 0)
3926 return var_meta_size;
3927
3928 meta_left -= var_meta_size;
3929
3930 return saved_meta_left - meta_left;
3931}
3932
3933static int btf_check_all_metas(struct btf_verifier_env *env)
3934{
3935 struct btf *btf = env->btf;
3936 struct btf_header *hdr;
3937 void *cur, *end;
3938
3939 hdr = &btf->hdr;
3940 cur = btf->nohdr_data + hdr->type_off;
3941 end = cur + hdr->type_len;
3942
3943 env->log_type_id = btf->base_btf ? btf->start_id : 1;
3944 while (cur < end) {
3945 struct btf_type *t = cur;
3946 s32 meta_size;
3947
3948 meta_size = btf_check_meta(env, t, end - cur);
3949 if (meta_size < 0)
3950 return meta_size;
3951
3952 btf_add_type(env, t);
3953 cur += meta_size;
3954 env->log_type_id++;
3955 }
3956
3957 return 0;
3958}
3959
3960static bool btf_resolve_valid(struct btf_verifier_env *env,
3961 const struct btf_type *t,
3962 u32 type_id)
3963{
3964 struct btf *btf = env->btf;
3965
3966 if (!env_type_is_resolved(env, type_id))
3967 return false;
3968
3969 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
3970 return !btf_resolved_type_id(btf, type_id) &&
3971 !btf_resolved_type_size(btf, type_id);
3972
3973 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
3974 btf_type_is_var(t)) {
3975 t = btf_type_id_resolve(btf, &type_id);
3976 return t &&
3977 !btf_type_is_modifier(t) &&
3978 !btf_type_is_var(t) &&
3979 !btf_type_is_datasec(t);
3980 }
3981
3982 if (btf_type_is_array(t)) {
3983 const struct btf_array *array = btf_type_array(t);
3984 const struct btf_type *elem_type;
3985 u32 elem_type_id = array->type;
3986 u32 elem_size;
3987
3988 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
3989 return elem_type && !btf_type_is_modifier(elem_type) &&
3990 (array->nelems * elem_size ==
3991 btf_resolved_type_size(btf, type_id));
3992 }
3993
3994 return false;
3995}
3996
3997static int btf_resolve(struct btf_verifier_env *env,
3998 const struct btf_type *t, u32 type_id)
3999{
4000 u32 save_log_type_id = env->log_type_id;
4001 const struct resolve_vertex *v;
4002 int err = 0;
4003
4004 env->resolve_mode = RESOLVE_TBD;
4005 env_stack_push(env, t, type_id);
4006 while (!err && (v = env_stack_peak(env))) {
4007 env->log_type_id = v->type_id;
4008 err = btf_type_ops(v->t)->resolve(env, v);
4009 }
4010
4011 env->log_type_id = type_id;
4012 if (err == -E2BIG) {
4013 btf_verifier_log_type(env, t,
4014 "Exceeded max resolving depth:%u",
4015 MAX_RESOLVE_DEPTH);
4016 } else if (err == -EEXIST) {
4017 btf_verifier_log_type(env, t, "Loop detected");
4018 }
4019
4020 /* Final sanity check */
4021 if (!err && !btf_resolve_valid(env, t, type_id)) {
4022 btf_verifier_log_type(env, t, "Invalid resolve state");
4023 err = -EINVAL;
4024 }
4025
4026 env->log_type_id = save_log_type_id;
4027 return err;
4028}
4029
4030static int btf_check_all_types(struct btf_verifier_env *env)
4031{
4032 struct btf *btf = env->btf;
4033 const struct btf_type *t;
4034 u32 type_id, i;
4035 int err;
4036
4037 err = env_resolve_init(env);
4038 if (err)
4039 return err;
4040
4041 env->phase++;
4042 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
4043 type_id = btf->start_id + i;
4044 t = btf_type_by_id(btf, type_id);
4045
4046 env->log_type_id = type_id;
4047 if (btf_type_needs_resolve(t) &&
4048 !env_type_is_resolved(env, type_id)) {
4049 err = btf_resolve(env, t, type_id);
4050 if (err)
4051 return err;
4052 }
4053
4054 if (btf_type_is_func_proto(t)) {
4055 err = btf_func_proto_check(env, t);
4056 if (err)
4057 return err;
4058 }
4059
4060 if (btf_type_is_func(t)) {
4061 err = btf_func_check(env, t);
4062 if (err)
4063 return err;
4064 }
4065 }
4066
4067 return 0;
4068}
4069
4070static int btf_parse_type_sec(struct btf_verifier_env *env)
4071{
4072 const struct btf_header *hdr = &env->btf->hdr;
4073 int err;
4074
4075 /* Type section must align to 4 bytes */
4076 if (hdr->type_off & (sizeof(u32) - 1)) {
4077 btf_verifier_log(env, "Unaligned type_off");
4078 return -EINVAL;
4079 }
4080
4081 if (!env->btf->base_btf && !hdr->type_len) {
4082 btf_verifier_log(env, "No type found");
4083 return -EINVAL;
4084 }
4085
4086 err = btf_check_all_metas(env);
4087 if (err)
4088 return err;
4089
4090 return btf_check_all_types(env);
4091}
4092
4093static int btf_parse_str_sec(struct btf_verifier_env *env)
4094{
4095 const struct btf_header *hdr;
4096 struct btf *btf = env->btf;
4097 const char *start, *end;
4098
4099 hdr = &btf->hdr;
4100 start = btf->nohdr_data + hdr->str_off;
4101 end = start + hdr->str_len;
4102
4103 if (end != btf->data + btf->data_size) {
4104 btf_verifier_log(env, "String section is not at the end");
4105 return -EINVAL;
4106 }
4107
4108 btf->strings = start;
4109
4110 if (btf->base_btf && !hdr->str_len)
4111 return 0;
4112 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
4113 btf_verifier_log(env, "Invalid string section");
4114 return -EINVAL;
4115 }
4116 if (!btf->base_btf && start[0]) {
4117 btf_verifier_log(env, "Invalid string section");
4118 return -EINVAL;
4119 }
4120
4121 return 0;
4122}
4123
4124static const size_t btf_sec_info_offset[] = {
4125 offsetof(struct btf_header, type_off),
4126 offsetof(struct btf_header, str_off),
4127};
4128
4129static int btf_sec_info_cmp(const void *a, const void *b)
4130{
4131 const struct btf_sec_info *x = a;
4132 const struct btf_sec_info *y = b;
4133
4134 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
4135}
4136
4137static int btf_check_sec_info(struct btf_verifier_env *env,
4138 u32 btf_data_size)
4139{
4140 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
4141 u32 total, expected_total, i;
4142 const struct btf_header *hdr;
4143 const struct btf *btf;
4144
4145 btf = env->btf;
4146 hdr = &btf->hdr;
4147
4148 /* Populate the secs from hdr */
4149 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
4150 secs[i] = *(struct btf_sec_info *)((void *)hdr +
4151 btf_sec_info_offset[i]);
4152
4153 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
4154 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
4155
4156 /* Check for gaps and overlap among sections */
4157 total = 0;
4158 expected_total = btf_data_size - hdr->hdr_len;
4159 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
4160 if (expected_total < secs[i].off) {
4161 btf_verifier_log(env, "Invalid section offset");
4162 return -EINVAL;
4163 }
4164 if (total < secs[i].off) {
4165 /* gap */
4166 btf_verifier_log(env, "Unsupported section found");
4167 return -EINVAL;
4168 }
4169 if (total > secs[i].off) {
4170 btf_verifier_log(env, "Section overlap found");
4171 return -EINVAL;
4172 }
4173 if (expected_total - total < secs[i].len) {
4174 btf_verifier_log(env,
4175 "Total section length too long");
4176 return -EINVAL;
4177 }
4178 total += secs[i].len;
4179 }
4180
4181 /* There is data other than hdr and known sections */
4182 if (expected_total != total) {
4183 btf_verifier_log(env, "Unsupported section found");
4184 return -EINVAL;
4185 }
4186
4187 return 0;
4188}
4189
4190static int btf_parse_hdr(struct btf_verifier_env *env)
4191{
4192 u32 hdr_len, hdr_copy, btf_data_size;
4193 const struct btf_header *hdr;
4194 struct btf *btf;
4195 int err;
4196
4197 btf = env->btf;
4198 btf_data_size = btf->data_size;
4199
4200 if (btf_data_size <
4201 offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) {
4202 btf_verifier_log(env, "hdr_len not found");
4203 return -EINVAL;
4204 }
4205
4206 hdr = btf->data;
4207 hdr_len = hdr->hdr_len;
4208 if (btf_data_size < hdr_len) {
4209 btf_verifier_log(env, "btf_header not found");
4210 return -EINVAL;
4211 }
4212
4213 /* Ensure the unsupported header fields are zero */
4214 if (hdr_len > sizeof(btf->hdr)) {
4215 u8 *expected_zero = btf->data + sizeof(btf->hdr);
4216 u8 *end = btf->data + hdr_len;
4217
4218 for (; expected_zero < end; expected_zero++) {
4219 if (*expected_zero) {
4220 btf_verifier_log(env, "Unsupported btf_header");
4221 return -E2BIG;
4222 }
4223 }
4224 }
4225
4226 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
4227 memcpy(&btf->hdr, btf->data, hdr_copy);
4228
4229 hdr = &btf->hdr;
4230
4231 btf_verifier_log_hdr(env, btf_data_size);
4232
4233 if (hdr->magic != BTF_MAGIC) {
4234 btf_verifier_log(env, "Invalid magic");
4235 return -EINVAL;
4236 }
4237
4238 if (hdr->version != BTF_VERSION) {
4239 btf_verifier_log(env, "Unsupported version");
4240 return -ENOTSUPP;
4241 }
4242
4243 if (hdr->flags) {
4244 btf_verifier_log(env, "Unsupported flags");
4245 return -ENOTSUPP;
4246 }
4247
4248 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
4249 btf_verifier_log(env, "No data");
4250 return -EINVAL;
4251 }
4252
4253 err = btf_check_sec_info(env, btf_data_size);
4254 if (err)
4255 return err;
4256
4257 return 0;
4258}
4259
4260static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
4261 u32 log_level, char __user *log_ubuf, u32 log_size)
4262{
4263 struct btf_verifier_env *env = NULL;
4264 struct bpf_verifier_log *log;
4265 struct btf *btf = NULL;
4266 u8 *data;
4267 int err;
4268
4269 if (btf_data_size > BTF_MAX_SIZE)
4270 return ERR_PTR(-E2BIG);
4271
4272 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4273 if (!env)
4274 return ERR_PTR(-ENOMEM);
4275
4276 log = &env->log;
4277 if (log_level || log_ubuf || log_size) {
4278 /* user requested verbose verifier output
4279 * and supplied buffer to store the verification trace
4280 */
4281 log->level = log_level;
4282 log->ubuf = log_ubuf;
4283 log->len_total = log_size;
4284
4285 /* log attributes have to be sane */
4286 if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
4287 !log->level || !log->ubuf) {
4288 err = -EINVAL;
4289 goto errout;
4290 }
4291 }
4292
4293 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4294 if (!btf) {
4295 err = -ENOMEM;
4296 goto errout;
4297 }
4298 env->btf = btf;
4299
4300 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
4301 if (!data) {
4302 err = -ENOMEM;
4303 goto errout;
4304 }
4305
4306 btf->data = data;
4307 btf->data_size = btf_data_size;
4308
4309 if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
4310 err = -EFAULT;
4311 goto errout;
4312 }
4313
4314 err = btf_parse_hdr(env);
4315 if (err)
4316 goto errout;
4317
4318 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4319
4320 err = btf_parse_str_sec(env);
4321 if (err)
4322 goto errout;
4323
4324 err = btf_parse_type_sec(env);
4325 if (err)
4326 goto errout;
4327
4328 if (log->level && bpf_verifier_log_full(log)) {
4329 err = -ENOSPC;
4330 goto errout;
4331 }
4332
4333 btf_verifier_env_free(env);
4334 refcount_set(&btf->refcnt, 1);
4335 return btf;
4336
4337errout:
4338 btf_verifier_env_free(env);
4339 if (btf)
4340 btf_free(btf);
4341 return ERR_PTR(err);
4342}
4343
4344extern char __weak __start_BTF[];
4345extern char __weak __stop_BTF[];
4346extern struct btf *btf_vmlinux;
4347
4348#define BPF_MAP_TYPE(_id, _ops)
4349#define BPF_LINK_TYPE(_id, _name)
4350static union {
4351 struct bpf_ctx_convert {
4352#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4353 prog_ctx_type _id##_prog; \
4354 kern_ctx_type _id##_kern;
4355#include <linux/bpf_types.h>
4356#undef BPF_PROG_TYPE
4357 } *__t;
4358 /* 't' is written once under lock. Read many times. */
4359 const struct btf_type *t;
4360} bpf_ctx_convert;
4361enum {
4362#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4363 __ctx_convert##_id,
4364#include <linux/bpf_types.h>
4365#undef BPF_PROG_TYPE
4366 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
4367};
4368static u8 bpf_ctx_convert_map[] = {
4369#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4370 [_id] = __ctx_convert##_id,
4371#include <linux/bpf_types.h>
4372#undef BPF_PROG_TYPE
4373 0, /* avoid empty array */
4374};
4375#undef BPF_MAP_TYPE
4376#undef BPF_LINK_TYPE
4377
4378static const struct btf_member *
4379btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
4380 const struct btf_type *t, enum bpf_prog_type prog_type,
4381 int arg)
4382{
4383 const struct btf_type *conv_struct;
4384 const struct btf_type *ctx_struct;
4385 const struct btf_member *ctx_type;
4386 const char *tname, *ctx_tname;
4387
4388 conv_struct = bpf_ctx_convert.t;
4389 if (!conv_struct) {
4390 bpf_log(log, "btf_vmlinux is malformed\n");
4391 return NULL;
4392 }
4393 t = btf_type_by_id(btf, t->type);
4394 while (btf_type_is_modifier(t))
4395 t = btf_type_by_id(btf, t->type);
4396 if (!btf_type_is_struct(t)) {
4397 /* Only pointer to struct is supported for now.
4398 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
4399 * is not supported yet.
4400 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
4401 */
4402 return NULL;
4403 }
4404 tname = btf_name_by_offset(btf, t->name_off);
4405 if (!tname) {
4406 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
4407 return NULL;
4408 }
4409 /* prog_type is valid bpf program type. No need for bounds check. */
4410 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
4411 /* ctx_struct is a pointer to prog_ctx_type in vmlinux.
4412 * Like 'struct __sk_buff'
4413 */
4414 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
4415 if (!ctx_struct)
4416 /* should not happen */
4417 return NULL;
4418 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
4419 if (!ctx_tname) {
4420 /* should not happen */
4421 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
4422 return NULL;
4423 }
4424 /* only compare that prog's ctx type name is the same as
4425 * kernel expects. No need to compare field by field.
4426 * It's ok for bpf prog to do:
4427 * struct __sk_buff {};
4428 * int socket_filter_bpf_prog(struct __sk_buff *skb)
4429 * { // no fields of skb are ever used }
4430 */
4431 if (strcmp(ctx_tname, tname))
4432 return NULL;
4433 return ctx_type;
4434}
4435
4436static const struct bpf_map_ops * const btf_vmlinux_map_ops[] = {
4437#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
4438#define BPF_LINK_TYPE(_id, _name)
4439#define BPF_MAP_TYPE(_id, _ops) \
4440 [_id] = &_ops,
4441#include <linux/bpf_types.h>
4442#undef BPF_PROG_TYPE
4443#undef BPF_LINK_TYPE
4444#undef BPF_MAP_TYPE
4445};
4446
4447static int btf_vmlinux_map_ids_init(const struct btf *btf,
4448 struct bpf_verifier_log *log)
4449{
4450 const struct bpf_map_ops *ops;
4451 int i, btf_id;
4452
4453 for (i = 0; i < ARRAY_SIZE(btf_vmlinux_map_ops); ++i) {
4454 ops = btf_vmlinux_map_ops[i];
4455 if (!ops || (!ops->map_btf_name && !ops->map_btf_id))
4456 continue;
4457 if (!ops->map_btf_name || !ops->map_btf_id) {
4458 bpf_log(log, "map type %d is misconfigured\n", i);
4459 return -EINVAL;
4460 }
4461 btf_id = btf_find_by_name_kind(btf, ops->map_btf_name,
4462 BTF_KIND_STRUCT);
4463 if (btf_id < 0)
4464 return btf_id;
4465 *ops->map_btf_id = btf_id;
4466 }
4467
4468 return 0;
4469}
4470
4471static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
4472 struct btf *btf,
4473 const struct btf_type *t,
4474 enum bpf_prog_type prog_type,
4475 int arg)
4476{
4477 const struct btf_member *prog_ctx_type, *kern_ctx_type;
4478
4479 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
4480 if (!prog_ctx_type)
4481 return -ENOENT;
4482 kern_ctx_type = prog_ctx_type + 1;
4483 return kern_ctx_type->type;
4484}
4485
4486BTF_ID_LIST(bpf_ctx_convert_btf_id)
4487BTF_ID(struct, bpf_ctx_convert)
4488
4489struct btf *btf_parse_vmlinux(void)
4490{
4491 struct btf_verifier_env *env = NULL;
4492 struct bpf_verifier_log *log;
4493 struct btf *btf = NULL;
4494 int err;
4495
4496 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4497 if (!env)
4498 return ERR_PTR(-ENOMEM);
4499
4500 log = &env->log;
4501 log->level = BPF_LOG_KERNEL;
4502
4503 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4504 if (!btf) {
4505 err = -ENOMEM;
4506 goto errout;
4507 }
4508 env->btf = btf;
4509
4510 btf->data = __start_BTF;
4511 btf->data_size = __stop_BTF - __start_BTF;
4512 btf->kernel_btf = true;
4513 snprintf(btf->name, sizeof(btf->name), "vmlinux");
4514
4515 err = btf_parse_hdr(env);
4516 if (err)
4517 goto errout;
4518
4519 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4520
4521 err = btf_parse_str_sec(env);
4522 if (err)
4523 goto errout;
4524
4525 err = btf_check_all_metas(env);
4526 if (err)
4527 goto errout;
4528
4529 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
4530 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
4531
4532 /* find bpf map structs for map_ptr access checking */
4533 err = btf_vmlinux_map_ids_init(btf, log);
4534 if (err < 0)
4535 goto errout;
4536
4537 bpf_struct_ops_init(btf, log);
4538
4539 refcount_set(&btf->refcnt, 1);
4540
4541 err = btf_alloc_id(btf);
4542 if (err)
4543 goto errout;
4544
4545 btf_verifier_env_free(env);
4546 return btf;
4547
4548errout:
4549 btf_verifier_env_free(env);
4550 if (btf) {
4551 kvfree(btf->types);
4552 kfree(btf);
4553 }
4554 return ERR_PTR(err);
4555}
4556
4557#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
4558
4559static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
4560{
4561 struct btf_verifier_env *env = NULL;
4562 struct bpf_verifier_log *log;
4563 struct btf *btf = NULL, *base_btf;
4564 int err;
4565
4566 base_btf = bpf_get_btf_vmlinux();
4567 if (IS_ERR(base_btf))
4568 return base_btf;
4569 if (!base_btf)
4570 return ERR_PTR(-EINVAL);
4571
4572 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4573 if (!env)
4574 return ERR_PTR(-ENOMEM);
4575
4576 log = &env->log;
4577 log->level = BPF_LOG_KERNEL;
4578
4579 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4580 if (!btf) {
4581 err = -ENOMEM;
4582 goto errout;
4583 }
4584 env->btf = btf;
4585
4586 btf->base_btf = base_btf;
4587 btf->start_id = base_btf->nr_types;
4588 btf->start_str_off = base_btf->hdr.str_len;
4589 btf->kernel_btf = true;
4590 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
4591
4592 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
4593 if (!btf->data) {
4594 err = -ENOMEM;
4595 goto errout;
4596 }
4597 memcpy(btf->data, data, data_size);
4598 btf->data_size = data_size;
4599
4600 err = btf_parse_hdr(env);
4601 if (err)
4602 goto errout;
4603
4604 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4605
4606 err = btf_parse_str_sec(env);
4607 if (err)
4608 goto errout;
4609
4610 err = btf_check_all_metas(env);
4611 if (err)
4612 goto errout;
4613
4614 btf_verifier_env_free(env);
4615 refcount_set(&btf->refcnt, 1);
4616 return btf;
4617
4618errout:
4619 btf_verifier_env_free(env);
4620 if (btf) {
4621 kvfree(btf->data);
4622 kvfree(btf->types);
4623 kfree(btf);
4624 }
4625 return ERR_PTR(err);
4626}
4627
4628#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
4629
4630struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
4631{
4632 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
4633
4634 if (tgt_prog)
4635 return tgt_prog->aux->btf;
4636 else
4637 return prog->aux->attach_btf;
4638}
4639
4640static bool is_string_ptr(struct btf *btf, const struct btf_type *t)
4641{
4642 /* t comes in already as a pointer */
4643 t = btf_type_by_id(btf, t->type);
4644
4645 /* allow const */
4646 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST)
4647 t = btf_type_by_id(btf, t->type);
4648
4649 /* char, signed char, unsigned char */
4650 return btf_type_is_int(t) && t->size == 1;
4651}
4652
4653bool btf_ctx_access(int off, int size, enum bpf_access_type type,
4654 const struct bpf_prog *prog,
4655 struct bpf_insn_access_aux *info)
4656{
4657 const struct btf_type *t = prog->aux->attach_func_proto;
4658 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
4659 struct btf *btf = bpf_prog_get_target_btf(prog);
4660 const char *tname = prog->aux->attach_func_name;
4661 struct bpf_verifier_log *log = info->log;
4662 const struct btf_param *args;
4663 u32 nr_args, arg;
4664 int i, ret;
4665
4666 if (off % 8) {
4667 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
4668 tname, off);
4669 return false;
4670 }
4671 arg = off / 8;
4672 args = (const struct btf_param *)(t + 1);
4673 /* if (t == NULL) Fall back to default BPF prog with
4674 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
4675 */
4676 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
4677 if (prog->aux->attach_btf_trace) {
4678 /* skip first 'void *__data' argument in btf_trace_##name typedef */
4679 args++;
4680 nr_args--;
4681 }
4682
4683 if (arg > nr_args) {
4684 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
4685 tname, arg + 1);
4686 return false;
4687 }
4688
4689 if (arg == nr_args) {
4690 switch (prog->expected_attach_type) {
4691 case BPF_LSM_MAC:
4692 case BPF_TRACE_FEXIT:
4693 /* When LSM programs are attached to void LSM hooks
4694 * they use FEXIT trampolines and when attached to
4695 * int LSM hooks, they use MODIFY_RETURN trampolines.
4696 *
4697 * While the LSM programs are BPF_MODIFY_RETURN-like
4698 * the check:
4699 *
4700 * if (ret_type != 'int')
4701 * return -EINVAL;
4702 *
4703 * is _not_ done here. This is still safe as LSM hooks
4704 * have only void and int return types.
4705 */
4706 if (!t)
4707 return true;
4708 t = btf_type_by_id(btf, t->type);
4709 break;
4710 case BPF_MODIFY_RETURN:
4711 /* For now the BPF_MODIFY_RETURN can only be attached to
4712 * functions that return an int.
4713 */
4714 if (!t)
4715 return false;
4716
4717 t = btf_type_skip_modifiers(btf, t->type, NULL);
4718 if (!btf_type_is_small_int(t)) {
4719 bpf_log(log,
4720 "ret type %s not allowed for fmod_ret\n",
4721 btf_kind_str[BTF_INFO_KIND(t->info)]);
4722 return false;
4723 }
4724 break;
4725 default:
4726 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
4727 tname, arg + 1);
4728 return false;
4729 }
4730 } else {
4731 if (!t)
4732 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
4733 return true;
4734 t = btf_type_by_id(btf, args[arg].type);
4735 }
4736
4737 /* skip modifiers */
4738 while (btf_type_is_modifier(t))
4739 t = btf_type_by_id(btf, t->type);
4740 if (btf_type_is_small_int(t) || btf_type_is_enum(t))
4741 /* accessing a scalar */
4742 return true;
4743 if (!btf_type_is_ptr(t)) {
4744 bpf_log(log,
4745 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
4746 tname, arg,
4747 __btf_name_by_offset(btf, t->name_off),
4748 btf_kind_str[BTF_INFO_KIND(t->info)]);
4749 return false;
4750 }
4751
4752 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
4753 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
4754 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
4755
4756 if (ctx_arg_info->offset == off &&
4757 (ctx_arg_info->reg_type == PTR_TO_RDONLY_BUF_OR_NULL ||
4758 ctx_arg_info->reg_type == PTR_TO_RDWR_BUF_OR_NULL)) {
4759 info->reg_type = ctx_arg_info->reg_type;
4760 return true;
4761 }
4762 }
4763
4764 if (t->type == 0)
4765 /* This is a pointer to void.
4766 * It is the same as scalar from the verifier safety pov.
4767 * No further pointer walking is allowed.
4768 */
4769 return true;
4770
4771 if (is_string_ptr(btf, t))
4772 return true;
4773
4774 /* this is a pointer to another type */
4775 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
4776 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
4777
4778 if (ctx_arg_info->offset == off) {
4779 info->reg_type = ctx_arg_info->reg_type;
4780 info->btf = btf_vmlinux;
4781 info->btf_id = ctx_arg_info->btf_id;
4782 return true;
4783 }
4784 }
4785
4786 info->reg_type = PTR_TO_BTF_ID;
4787 if (tgt_prog) {
4788 enum bpf_prog_type tgt_type;
4789
4790 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
4791 tgt_type = tgt_prog->aux->saved_dst_prog_type;
4792 else
4793 tgt_type = tgt_prog->type;
4794
4795 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
4796 if (ret > 0) {
4797 info->btf = btf_vmlinux;
4798 info->btf_id = ret;
4799 return true;
4800 } else {
4801 return false;
4802 }
4803 }
4804
4805 info->btf = btf;
4806 info->btf_id = t->type;
4807 t = btf_type_by_id(btf, t->type);
4808 /* skip modifiers */
4809 while (btf_type_is_modifier(t)) {
4810 info->btf_id = t->type;
4811 t = btf_type_by_id(btf, t->type);
4812 }
4813 if (!btf_type_is_struct(t)) {
4814 bpf_log(log,
4815 "func '%s' arg%d type %s is not a struct\n",
4816 tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]);
4817 return false;
4818 }
4819 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
4820 tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)],
4821 __btf_name_by_offset(btf, t->name_off));
4822 return true;
4823}
4824
4825enum bpf_struct_walk_result {
4826 /* < 0 error */
4827 WALK_SCALAR = 0,
4828 WALK_PTR,
4829 WALK_STRUCT,
4830};
4831
4832static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
4833 const struct btf_type *t, int off, int size,
4834 u32 *next_btf_id)
4835{
4836 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
4837 const struct btf_type *mtype, *elem_type = NULL;
4838 const struct btf_member *member;
4839 const char *tname, *mname;
4840 u32 vlen, elem_id, mid;
4841
4842again:
4843 tname = __btf_name_by_offset(btf, t->name_off);
4844 if (!btf_type_is_struct(t)) {
4845 bpf_log(log, "Type '%s' is not a struct\n", tname);
4846 return -EINVAL;
4847 }
4848
4849 vlen = btf_type_vlen(t);
4850 if (off + size > t->size) {
4851 /* If the last element is a variable size array, we may
4852 * need to relax the rule.
4853 */
4854 struct btf_array *array_elem;
4855
4856 if (vlen == 0)
4857 goto error;
4858
4859 member = btf_type_member(t) + vlen - 1;
4860 mtype = btf_type_skip_modifiers(btf, member->type,
4861 NULL);
4862 if (!btf_type_is_array(mtype))
4863 goto error;
4864
4865 array_elem = (struct btf_array *)(mtype + 1);
4866 if (array_elem->nelems != 0)
4867 goto error;
4868
4869 moff = btf_member_bit_offset(t, member) / 8;
4870 if (off < moff)
4871 goto error;
4872
4873 /* Only allow structure for now, can be relaxed for
4874 * other types later.
4875 */
4876 t = btf_type_skip_modifiers(btf, array_elem->type,
4877 NULL);
4878 if (!btf_type_is_struct(t))
4879 goto error;
4880
4881 off = (off - moff) % t->size;
4882 goto again;
4883
4884error:
4885 bpf_log(log, "access beyond struct %s at off %u size %u\n",
4886 tname, off, size);
4887 return -EACCES;
4888 }
4889
4890 for_each_member(i, t, member) {
4891 /* offset of the field in bytes */
4892 moff = btf_member_bit_offset(t, member) / 8;
4893 if (off + size <= moff)
4894 /* won't find anything, field is already too far */
4895 break;
4896
4897 if (btf_member_bitfield_size(t, member)) {
4898 u32 end_bit = btf_member_bit_offset(t, member) +
4899 btf_member_bitfield_size(t, member);
4900
4901 /* off <= moff instead of off == moff because clang
4902 * does not generate a BTF member for anonymous
4903 * bitfield like the ":16" here:
4904 * struct {
4905 * int :16;
4906 * int x:8;
4907 * };
4908 */
4909 if (off <= moff &&
4910 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
4911 return WALK_SCALAR;
4912
4913 /* off may be accessing a following member
4914 *
4915 * or
4916 *
4917 * Doing partial access at either end of this
4918 * bitfield. Continue on this case also to
4919 * treat it as not accessing this bitfield
4920 * and eventually error out as field not
4921 * found to keep it simple.
4922 * It could be relaxed if there was a legit
4923 * partial access case later.
4924 */
4925 continue;
4926 }
4927
4928 /* In case of "off" is pointing to holes of a struct */
4929 if (off < moff)
4930 break;
4931
4932 /* type of the field */
4933 mid = member->type;
4934 mtype = btf_type_by_id(btf, member->type);
4935 mname = __btf_name_by_offset(btf, member->name_off);
4936
4937 mtype = __btf_resolve_size(btf, mtype, &msize,
4938 &elem_type, &elem_id, &total_nelems,
4939 &mid);
4940 if (IS_ERR(mtype)) {
4941 bpf_log(log, "field %s doesn't have size\n", mname);
4942 return -EFAULT;
4943 }
4944
4945 mtrue_end = moff + msize;
4946 if (off >= mtrue_end)
4947 /* no overlap with member, keep iterating */
4948 continue;
4949
4950 if (btf_type_is_array(mtype)) {
4951 u32 elem_idx;
4952
4953 /* __btf_resolve_size() above helps to
4954 * linearize a multi-dimensional array.
4955 *
4956 * The logic here is treating an array
4957 * in a struct as the following way:
4958 *
4959 * struct outer {
4960 * struct inner array[2][2];
4961 * };
4962 *
4963 * looks like:
4964 *
4965 * struct outer {
4966 * struct inner array_elem0;
4967 * struct inner array_elem1;
4968 * struct inner array_elem2;
4969 * struct inner array_elem3;
4970 * };
4971 *
4972 * When accessing outer->array[1][0], it moves
4973 * moff to "array_elem2", set mtype to
4974 * "struct inner", and msize also becomes
4975 * sizeof(struct inner). Then most of the
4976 * remaining logic will fall through without
4977 * caring the current member is an array or
4978 * not.
4979 *
4980 * Unlike mtype/msize/moff, mtrue_end does not
4981 * change. The naming difference ("_true") tells
4982 * that it is not always corresponding to
4983 * the current mtype/msize/moff.
4984 * It is the true end of the current
4985 * member (i.e. array in this case). That
4986 * will allow an int array to be accessed like
4987 * a scratch space,
4988 * i.e. allow access beyond the size of
4989 * the array's element as long as it is
4990 * within the mtrue_end boundary.
4991 */
4992
4993 /* skip empty array */
4994 if (moff == mtrue_end)
4995 continue;
4996
4997 msize /= total_nelems;
4998 elem_idx = (off - moff) / msize;
4999 moff += elem_idx * msize;
5000 mtype = elem_type;
5001 mid = elem_id;
5002 }
5003
5004 /* the 'off' we're looking for is either equal to start
5005 * of this field or inside of this struct
5006 */
5007 if (btf_type_is_struct(mtype)) {
5008 /* our field must be inside that union or struct */
5009 t = mtype;
5010
5011 /* return if the offset matches the member offset */
5012 if (off == moff) {
5013 *next_btf_id = mid;
5014 return WALK_STRUCT;
5015 }
5016
5017 /* adjust offset we're looking for */
5018 off -= moff;
5019 goto again;
5020 }
5021
5022 if (btf_type_is_ptr(mtype)) {
5023 const struct btf_type *stype;
5024 u32 id;
5025
5026 if (msize != size || off != moff) {
5027 bpf_log(log,
5028 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
5029 mname, moff, tname, off, size);
5030 return -EACCES;
5031 }
5032 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
5033 if (btf_type_is_struct(stype)) {
5034 *next_btf_id = id;
5035 return WALK_PTR;
5036 }
5037 }
5038
5039 /* Allow more flexible access within an int as long as
5040 * it is within mtrue_end.
5041 * Since mtrue_end could be the end of an array,
5042 * that also allows using an array of int as a scratch
5043 * space. e.g. skb->cb[].
5044 */
5045 if (off + size > mtrue_end) {
5046 bpf_log(log,
5047 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
5048 mname, mtrue_end, tname, off, size);
5049 return -EACCES;
5050 }
5051
5052 return WALK_SCALAR;
5053 }
5054 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
5055 return -EINVAL;
5056}
5057
5058int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
5059 const struct btf_type *t, int off, int size,
5060 enum bpf_access_type atype __maybe_unused,
5061 u32 *next_btf_id)
5062{
5063 int err;
5064 u32 id;
5065
5066 do {
5067 err = btf_struct_walk(log, btf, t, off, size, &id);
5068
5069 switch (err) {
5070 case WALK_PTR:
5071 /* If we found the pointer or scalar on t+off,
5072 * we're done.
5073 */
5074 *next_btf_id = id;
5075 return PTR_TO_BTF_ID;
5076 case WALK_SCALAR:
5077 return SCALAR_VALUE;
5078 case WALK_STRUCT:
5079 /* We found nested struct, so continue the search
5080 * by diving in it. At this point the offset is
5081 * aligned with the new type, so set it to 0.
5082 */
5083 t = btf_type_by_id(btf, id);
5084 off = 0;
5085 break;
5086 default:
5087 /* It's either error or unknown return value..
5088 * scream and leave.
5089 */
5090 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
5091 return -EINVAL;
5092 return err;
5093 }
5094 } while (t);
5095
5096 return -EINVAL;
5097}
5098
5099/* Check that two BTF types, each specified as an BTF object + id, are exactly
5100 * the same. Trivial ID check is not enough due to module BTFs, because we can
5101 * end up with two different module BTFs, but IDs point to the common type in
5102 * vmlinux BTF.
5103 */
5104static bool btf_types_are_same(const struct btf *btf1, u32 id1,
5105 const struct btf *btf2, u32 id2)
5106{
5107 if (id1 != id2)
5108 return false;
5109 if (btf1 == btf2)
5110 return true;
5111 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
5112}
5113
5114bool btf_struct_ids_match(struct bpf_verifier_log *log,
5115 const struct btf *btf, u32 id, int off,
5116 const struct btf *need_btf, u32 need_type_id)
5117{
5118 const struct btf_type *type;
5119 int err;
5120
5121 /* Are we already done? */
5122 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
5123 return true;
5124
5125again:
5126 type = btf_type_by_id(btf, id);
5127 if (!type)
5128 return false;
5129 err = btf_struct_walk(log, btf, type, off, 1, &id);
5130 if (err != WALK_STRUCT)
5131 return false;
5132
5133 /* We found nested struct object. If it matches
5134 * the requested ID, we're done. Otherwise let's
5135 * continue the search with offset 0 in the new
5136 * type.
5137 */
5138 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
5139 off = 0;
5140 goto again;
5141 }
5142
5143 return true;
5144}
5145
5146static int __get_type_size(struct btf *btf, u32 btf_id,
5147 const struct btf_type **bad_type)
5148{
5149 const struct btf_type *t;
5150
5151 if (!btf_id)
5152 /* void */
5153 return 0;
5154 t = btf_type_by_id(btf, btf_id);
5155 while (t && btf_type_is_modifier(t))
5156 t = btf_type_by_id(btf, t->type);
5157 if (!t) {
5158 *bad_type = btf_type_by_id(btf, 0);
5159 return -EINVAL;
5160 }
5161 if (btf_type_is_ptr(t))
5162 /* kernel size of pointer. Not BPF's size of pointer*/
5163 return sizeof(void *);
5164 if (btf_type_is_int(t) || btf_type_is_enum(t))
5165 return t->size;
5166 *bad_type = t;
5167 return -EINVAL;
5168}
5169
5170int btf_distill_func_proto(struct bpf_verifier_log *log,
5171 struct btf *btf,
5172 const struct btf_type *func,
5173 const char *tname,
5174 struct btf_func_model *m)
5175{
5176 const struct btf_param *args;
5177 const struct btf_type *t;
5178 u32 i, nargs;
5179 int ret;
5180
5181 if (!func) {
5182 /* BTF function prototype doesn't match the verifier types.
5183 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
5184 */
5185 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
5186 m->arg_size[i] = 8;
5187 m->ret_size = 8;
5188 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
5189 return 0;
5190 }
5191 args = (const struct btf_param *)(func + 1);
5192 nargs = btf_type_vlen(func);
5193 if (nargs >= MAX_BPF_FUNC_ARGS) {
5194 bpf_log(log,
5195 "The function %s has %d arguments. Too many.\n",
5196 tname, nargs);
5197 return -EINVAL;
5198 }
5199 ret = __get_type_size(btf, func->type, &t);
5200 if (ret < 0) {
5201 bpf_log(log,
5202 "The function %s return type %s is unsupported.\n",
5203 tname, btf_kind_str[BTF_INFO_KIND(t->info)]);
5204 return -EINVAL;
5205 }
5206 m->ret_size = ret;
5207
5208 for (i = 0; i < nargs; i++) {
5209 if (i == nargs - 1 && args[i].type == 0) {
5210 bpf_log(log,
5211 "The function %s with variable args is unsupported.\n",
5212 tname);
5213 return -EINVAL;
5214 }
5215 ret = __get_type_size(btf, args[i].type, &t);
5216 if (ret < 0) {
5217 bpf_log(log,
5218 "The function %s arg%d type %s is unsupported.\n",
5219 tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]);
5220 return -EINVAL;
5221 }
5222 if (ret == 0) {
5223 bpf_log(log,
5224 "The function %s has malformed void argument.\n",
5225 tname);
5226 return -EINVAL;
5227 }
5228 m->arg_size[i] = ret;
5229 }
5230 m->nr_args = nargs;
5231 return 0;
5232}
5233
5234/* Compare BTFs of two functions assuming only scalars and pointers to context.
5235 * t1 points to BTF_KIND_FUNC in btf1
5236 * t2 points to BTF_KIND_FUNC in btf2
5237 * Returns:
5238 * EINVAL - function prototype mismatch
5239 * EFAULT - verifier bug
5240 * 0 - 99% match. The last 1% is validated by the verifier.
5241 */
5242static int btf_check_func_type_match(struct bpf_verifier_log *log,
5243 struct btf *btf1, const struct btf_type *t1,
5244 struct btf *btf2, const struct btf_type *t2)
5245{
5246 const struct btf_param *args1, *args2;
5247 const char *fn1, *fn2, *s1, *s2;
5248 u32 nargs1, nargs2, i;
5249
5250 fn1 = btf_name_by_offset(btf1, t1->name_off);
5251 fn2 = btf_name_by_offset(btf2, t2->name_off);
5252
5253 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
5254 bpf_log(log, "%s() is not a global function\n", fn1);
5255 return -EINVAL;
5256 }
5257 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
5258 bpf_log(log, "%s() is not a global function\n", fn2);
5259 return -EINVAL;
5260 }
5261
5262 t1 = btf_type_by_id(btf1, t1->type);
5263 if (!t1 || !btf_type_is_func_proto(t1))
5264 return -EFAULT;
5265 t2 = btf_type_by_id(btf2, t2->type);
5266 if (!t2 || !btf_type_is_func_proto(t2))
5267 return -EFAULT;
5268
5269 args1 = (const struct btf_param *)(t1 + 1);
5270 nargs1 = btf_type_vlen(t1);
5271 args2 = (const struct btf_param *)(t2 + 1);
5272 nargs2 = btf_type_vlen(t2);
5273
5274 if (nargs1 != nargs2) {
5275 bpf_log(log, "%s() has %d args while %s() has %d args\n",
5276 fn1, nargs1, fn2, nargs2);
5277 return -EINVAL;
5278 }
5279
5280 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5281 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5282 if (t1->info != t2->info) {
5283 bpf_log(log,
5284 "Return type %s of %s() doesn't match type %s of %s()\n",
5285 btf_type_str(t1), fn1,
5286 btf_type_str(t2), fn2);
5287 return -EINVAL;
5288 }
5289
5290 for (i = 0; i < nargs1; i++) {
5291 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
5292 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
5293
5294 if (t1->info != t2->info) {
5295 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
5296 i, fn1, btf_type_str(t1),
5297 fn2, btf_type_str(t2));
5298 return -EINVAL;
5299 }
5300 if (btf_type_has_size(t1) && t1->size != t2->size) {
5301 bpf_log(log,
5302 "arg%d in %s() has size %d while %s() has %d\n",
5303 i, fn1, t1->size,
5304 fn2, t2->size);
5305 return -EINVAL;
5306 }
5307
5308 /* global functions are validated with scalars and pointers
5309 * to context only. And only global functions can be replaced.
5310 * Hence type check only those types.
5311 */
5312 if (btf_type_is_int(t1) || btf_type_is_enum(t1))
5313 continue;
5314 if (!btf_type_is_ptr(t1)) {
5315 bpf_log(log,
5316 "arg%d in %s() has unrecognized type\n",
5317 i, fn1);
5318 return -EINVAL;
5319 }
5320 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5321 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5322 if (!btf_type_is_struct(t1)) {
5323 bpf_log(log,
5324 "arg%d in %s() is not a pointer to context\n",
5325 i, fn1);
5326 return -EINVAL;
5327 }
5328 if (!btf_type_is_struct(t2)) {
5329 bpf_log(log,
5330 "arg%d in %s() is not a pointer to context\n",
5331 i, fn2);
5332 return -EINVAL;
5333 }
5334 /* This is an optional check to make program writing easier.
5335 * Compare names of structs and report an error to the user.
5336 * btf_prepare_func_args() already checked that t2 struct
5337 * is a context type. btf_prepare_func_args() will check
5338 * later that t1 struct is a context type as well.
5339 */
5340 s1 = btf_name_by_offset(btf1, t1->name_off);
5341 s2 = btf_name_by_offset(btf2, t2->name_off);
5342 if (strcmp(s1, s2)) {
5343 bpf_log(log,
5344 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
5345 i, fn1, s1, fn2, s2);
5346 return -EINVAL;
5347 }
5348 }
5349 return 0;
5350}
5351
5352/* Compare BTFs of given program with BTF of target program */
5353int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
5354 struct btf *btf2, const struct btf_type *t2)
5355{
5356 struct btf *btf1 = prog->aux->btf;
5357 const struct btf_type *t1;
5358 u32 btf_id = 0;
5359
5360 if (!prog->aux->func_info) {
5361 bpf_log(log, "Program extension requires BTF\n");
5362 return -EINVAL;
5363 }
5364
5365 btf_id = prog->aux->func_info[0].type_id;
5366 if (!btf_id)
5367 return -EFAULT;
5368
5369 t1 = btf_type_by_id(btf1, btf_id);
5370 if (!t1 || !btf_type_is_func(t1))
5371 return -EFAULT;
5372
5373 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
5374}
5375
5376static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
5377#ifdef CONFIG_NET
5378 [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
5379 [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
5380 [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
5381#endif
5382};
5383
5384static int btf_check_func_arg_match(struct bpf_verifier_env *env,
5385 const struct btf *btf, u32 func_id,
5386 struct bpf_reg_state *regs,
5387 bool ptr_to_mem_ok)
5388{
5389 struct bpf_verifier_log *log = &env->log;
5390 const char *func_name, *ref_tname;
5391 const struct btf_type *t, *ref_t;
5392 const struct btf_param *args;
5393 u32 i, nargs, ref_id;
5394
5395 t = btf_type_by_id(btf, func_id);
5396 if (!t || !btf_type_is_func(t)) {
5397 /* These checks were already done by the verifier while loading
5398 * struct bpf_func_info or in add_kfunc_call().
5399 */
5400 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
5401 func_id);
5402 return -EFAULT;
5403 }
5404 func_name = btf_name_by_offset(btf, t->name_off);
5405
5406 t = btf_type_by_id(btf, t->type);
5407 if (!t || !btf_type_is_func_proto(t)) {
5408 bpf_log(log, "Invalid BTF of func %s\n", func_name);
5409 return -EFAULT;
5410 }
5411 args = (const struct btf_param *)(t + 1);
5412 nargs = btf_type_vlen(t);
5413 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
5414 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
5415 MAX_BPF_FUNC_REG_ARGS);
5416 return -EINVAL;
5417 }
5418
5419 /* check that BTF function arguments match actual types that the
5420 * verifier sees.
5421 */
5422 for (i = 0; i < nargs; i++) {
5423 u32 regno = i + 1;
5424 struct bpf_reg_state *reg = ®s[regno];
5425
5426 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
5427 if (btf_type_is_scalar(t)) {
5428 if (reg->type == SCALAR_VALUE)
5429 continue;
5430 bpf_log(log, "R%d is not a scalar\n", regno);
5431 return -EINVAL;
5432 }
5433
5434 if (!btf_type_is_ptr(t)) {
5435 bpf_log(log, "Unrecognized arg#%d type %s\n",
5436 i, btf_type_str(t));
5437 return -EINVAL;
5438 }
5439
5440 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
5441 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
5442 if (btf_is_kernel(btf)) {
5443 const struct btf_type *reg_ref_t;
5444 const struct btf *reg_btf;
5445 const char *reg_ref_tname;
5446 u32 reg_ref_id;
5447
5448 if (!btf_type_is_struct(ref_t)) {
5449 bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
5450 func_name, i, btf_type_str(ref_t),
5451 ref_tname);
5452 return -EINVAL;
5453 }
5454
5455 if (reg->type == PTR_TO_BTF_ID) {
5456 reg_btf = reg->btf;
5457 reg_ref_id = reg->btf_id;
5458 } else if (reg2btf_ids[reg->type]) {
5459 reg_btf = btf_vmlinux;
5460 reg_ref_id = *reg2btf_ids[reg->type];
5461 } else {
5462 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d is not a pointer to btf_id\n",
5463 func_name, i,
5464 btf_type_str(ref_t), ref_tname, regno);
5465 return -EINVAL;
5466 }
5467
5468 reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
5469 ®_ref_id);
5470 reg_ref_tname = btf_name_by_offset(reg_btf,
5471 reg_ref_t->name_off);
5472 if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
5473 reg->off, btf, ref_id)) {
5474 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
5475 func_name, i,
5476 btf_type_str(ref_t), ref_tname,
5477 regno, btf_type_str(reg_ref_t),
5478 reg_ref_tname);
5479 return -EINVAL;
5480 }
5481 } else if (btf_get_prog_ctx_type(log, btf, t,
5482 env->prog->type, i)) {
5483 /* If function expects ctx type in BTF check that caller
5484 * is passing PTR_TO_CTX.
5485 */
5486 if (reg->type != PTR_TO_CTX) {
5487 bpf_log(log,
5488 "arg#%d expected pointer to ctx, but got %s\n",
5489 i, btf_type_str(t));
5490 return -EINVAL;
5491 }
5492 if (check_ctx_reg(env, reg, regno))
5493 return -EINVAL;
5494 } else if (ptr_to_mem_ok) {
5495 const struct btf_type *resolve_ret;
5496 u32 type_size;
5497
5498 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
5499 if (IS_ERR(resolve_ret)) {
5500 bpf_log(log,
5501 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
5502 i, btf_type_str(ref_t), ref_tname,
5503 PTR_ERR(resolve_ret));
5504 return -EINVAL;
5505 }
5506
5507 if (check_mem_reg(env, reg, regno, type_size))
5508 return -EINVAL;
5509 } else {
5510 return -EINVAL;
5511 }
5512 }
5513
5514 return 0;
5515}
5516
5517/* Compare BTF of a function with given bpf_reg_state.
5518 * Returns:
5519 * EFAULT - there is a verifier bug. Abort verification.
5520 * EINVAL - there is a type mismatch or BTF is not available.
5521 * 0 - BTF matches with what bpf_reg_state expects.
5522 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
5523 */
5524int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
5525 struct bpf_reg_state *regs)
5526{
5527 struct bpf_prog *prog = env->prog;
5528 struct btf *btf = prog->aux->btf;
5529 bool is_global;
5530 u32 btf_id;
5531 int err;
5532
5533 if (!prog->aux->func_info)
5534 return -EINVAL;
5535
5536 btf_id = prog->aux->func_info[subprog].type_id;
5537 if (!btf_id)
5538 return -EFAULT;
5539
5540 if (prog->aux->func_info_aux[subprog].unreliable)
5541 return -EINVAL;
5542
5543 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
5544 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global);
5545
5546 /* Compiler optimizations can remove arguments from static functions
5547 * or mismatched type can be passed into a global function.
5548 * In such cases mark the function as unreliable from BTF point of view.
5549 */
5550 if (err)
5551 prog->aux->func_info_aux[subprog].unreliable = true;
5552 return err;
5553}
5554
5555int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
5556 const struct btf *btf, u32 func_id,
5557 struct bpf_reg_state *regs)
5558{
5559 return btf_check_func_arg_match(env, btf, func_id, regs, false);
5560}
5561
5562/* Convert BTF of a function into bpf_reg_state if possible
5563 * Returns:
5564 * EFAULT - there is a verifier bug. Abort verification.
5565 * EINVAL - cannot convert BTF.
5566 * 0 - Successfully converted BTF into bpf_reg_state
5567 * (either PTR_TO_CTX or SCALAR_VALUE).
5568 */
5569int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
5570 struct bpf_reg_state *regs)
5571{
5572 struct bpf_verifier_log *log = &env->log;
5573 struct bpf_prog *prog = env->prog;
5574 enum bpf_prog_type prog_type = prog->type;
5575 struct btf *btf = prog->aux->btf;
5576 const struct btf_param *args;
5577 const struct btf_type *t, *ref_t;
5578 u32 i, nargs, btf_id;
5579 const char *tname;
5580
5581 if (!prog->aux->func_info ||
5582 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
5583 bpf_log(log, "Verifier bug\n");
5584 return -EFAULT;
5585 }
5586
5587 btf_id = prog->aux->func_info[subprog].type_id;
5588 if (!btf_id) {
5589 bpf_log(log, "Global functions need valid BTF\n");
5590 return -EFAULT;
5591 }
5592
5593 t = btf_type_by_id(btf, btf_id);
5594 if (!t || !btf_type_is_func(t)) {
5595 /* These checks were already done by the verifier while loading
5596 * struct bpf_func_info
5597 */
5598 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
5599 subprog);
5600 return -EFAULT;
5601 }
5602 tname = btf_name_by_offset(btf, t->name_off);
5603
5604 if (log->level & BPF_LOG_LEVEL)
5605 bpf_log(log, "Validating %s() func#%d...\n",
5606 tname, subprog);
5607
5608 if (prog->aux->func_info_aux[subprog].unreliable) {
5609 bpf_log(log, "Verifier bug in function %s()\n", tname);
5610 return -EFAULT;
5611 }
5612 if (prog_type == BPF_PROG_TYPE_EXT)
5613 prog_type = prog->aux->dst_prog->type;
5614
5615 t = btf_type_by_id(btf, t->type);
5616 if (!t || !btf_type_is_func_proto(t)) {
5617 bpf_log(log, "Invalid type of function %s()\n", tname);
5618 return -EFAULT;
5619 }
5620 args = (const struct btf_param *)(t + 1);
5621 nargs = btf_type_vlen(t);
5622 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
5623 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
5624 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
5625 return -EINVAL;
5626 }
5627 /* check that function returns int */
5628 t = btf_type_by_id(btf, t->type);
5629 while (btf_type_is_modifier(t))
5630 t = btf_type_by_id(btf, t->type);
5631 if (!btf_type_is_int(t) && !btf_type_is_enum(t)) {
5632 bpf_log(log,
5633 "Global function %s() doesn't return scalar. Only those are supported.\n",
5634 tname);
5635 return -EINVAL;
5636 }
5637 /* Convert BTF function arguments into verifier types.
5638 * Only PTR_TO_CTX and SCALAR are supported atm.
5639 */
5640 for (i = 0; i < nargs; i++) {
5641 struct bpf_reg_state *reg = ®s[i + 1];
5642
5643 t = btf_type_by_id(btf, args[i].type);
5644 while (btf_type_is_modifier(t))
5645 t = btf_type_by_id(btf, t->type);
5646 if (btf_type_is_int(t) || btf_type_is_enum(t)) {
5647 reg->type = SCALAR_VALUE;
5648 continue;
5649 }
5650 if (btf_type_is_ptr(t)) {
5651 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
5652 reg->type = PTR_TO_CTX;
5653 continue;
5654 }
5655
5656 t = btf_type_skip_modifiers(btf, t->type, NULL);
5657
5658 ref_t = btf_resolve_size(btf, t, ®->mem_size);
5659 if (IS_ERR(ref_t)) {
5660 bpf_log(log,
5661 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
5662 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
5663 PTR_ERR(ref_t));
5664 return -EINVAL;
5665 }
5666
5667 reg->type = PTR_TO_MEM_OR_NULL;
5668 reg->id = ++env->id_gen;
5669
5670 continue;
5671 }
5672 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
5673 i, btf_kind_str[BTF_INFO_KIND(t->info)], tname);
5674 return -EINVAL;
5675 }
5676 return 0;
5677}
5678
5679static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
5680 struct btf_show *show)
5681{
5682 const struct btf_type *t = btf_type_by_id(btf, type_id);
5683
5684 show->btf = btf;
5685 memset(&show->state, 0, sizeof(show->state));
5686 memset(&show->obj, 0, sizeof(show->obj));
5687
5688 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
5689}
5690
5691static void btf_seq_show(struct btf_show *show, const char *fmt,
5692 va_list args)
5693{
5694 seq_vprintf((struct seq_file *)show->target, fmt, args);
5695}
5696
5697int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
5698 void *obj, struct seq_file *m, u64 flags)
5699{
5700 struct btf_show sseq;
5701
5702 sseq.target = m;
5703 sseq.showfn = btf_seq_show;
5704 sseq.flags = flags;
5705
5706 btf_type_show(btf, type_id, obj, &sseq);
5707
5708 return sseq.state.status;
5709}
5710
5711void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
5712 struct seq_file *m)
5713{
5714 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
5715 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
5716 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
5717}
5718
5719struct btf_show_snprintf {
5720 struct btf_show show;
5721 int len_left; /* space left in string */
5722 int len; /* length we would have written */
5723};
5724
5725static void btf_snprintf_show(struct btf_show *show, const char *fmt,
5726 va_list args)
5727{
5728 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
5729 int len;
5730
5731 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
5732
5733 if (len < 0) {
5734 ssnprintf->len_left = 0;
5735 ssnprintf->len = len;
5736 } else if (len > ssnprintf->len_left) {
5737 /* no space, drive on to get length we would have written */
5738 ssnprintf->len_left = 0;
5739 ssnprintf->len += len;
5740 } else {
5741 ssnprintf->len_left -= len;
5742 ssnprintf->len += len;
5743 show->target += len;
5744 }
5745}
5746
5747int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
5748 char *buf, int len, u64 flags)
5749{
5750 struct btf_show_snprintf ssnprintf;
5751
5752 ssnprintf.show.target = buf;
5753 ssnprintf.show.flags = flags;
5754 ssnprintf.show.showfn = btf_snprintf_show;
5755 ssnprintf.len_left = len;
5756 ssnprintf.len = 0;
5757
5758 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
5759
5760 /* If we encontered an error, return it. */
5761 if (ssnprintf.show.state.status)
5762 return ssnprintf.show.state.status;
5763
5764 /* Otherwise return length we would have written */
5765 return ssnprintf.len;
5766}
5767
5768#ifdef CONFIG_PROC_FS
5769static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
5770{
5771 const struct btf *btf = filp->private_data;
5772
5773 seq_printf(m, "btf_id:\t%u\n", btf->id);
5774}
5775#endif
5776
5777static int btf_release(struct inode *inode, struct file *filp)
5778{
5779 btf_put(filp->private_data);
5780 return 0;
5781}
5782
5783const struct file_operations btf_fops = {
5784#ifdef CONFIG_PROC_FS
5785 .show_fdinfo = bpf_btf_show_fdinfo,
5786#endif
5787 .release = btf_release,
5788};
5789
5790static int __btf_new_fd(struct btf *btf)
5791{
5792 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
5793}
5794
5795int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
5796{
5797 struct btf *btf;
5798 int ret;
5799
5800 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
5801 attr->btf_size, attr->btf_log_level,
5802 u64_to_user_ptr(attr->btf_log_buf),
5803 attr->btf_log_size);
5804 if (IS_ERR(btf))
5805 return PTR_ERR(btf);
5806
5807 ret = btf_alloc_id(btf);
5808 if (ret) {
5809 btf_free(btf);
5810 return ret;
5811 }
5812
5813 /*
5814 * The BTF ID is published to the userspace.
5815 * All BTF free must go through call_rcu() from
5816 * now on (i.e. free by calling btf_put()).
5817 */
5818
5819 ret = __btf_new_fd(btf);
5820 if (ret < 0)
5821 btf_put(btf);
5822
5823 return ret;
5824}
5825
5826struct btf *btf_get_by_fd(int fd)
5827{
5828 struct btf *btf;
5829 struct fd f;
5830
5831 f = fdget(fd);
5832
5833 if (!f.file)
5834 return ERR_PTR(-EBADF);
5835
5836 if (f.file->f_op != &btf_fops) {
5837 fdput(f);
5838 return ERR_PTR(-EINVAL);
5839 }
5840
5841 btf = f.file->private_data;
5842 refcount_inc(&btf->refcnt);
5843 fdput(f);
5844
5845 return btf;
5846}
5847
5848int btf_get_info_by_fd(const struct btf *btf,
5849 const union bpf_attr *attr,
5850 union bpf_attr __user *uattr)
5851{
5852 struct bpf_btf_info __user *uinfo;
5853 struct bpf_btf_info info;
5854 u32 info_copy, btf_copy;
5855 void __user *ubtf;
5856 char __user *uname;
5857 u32 uinfo_len, uname_len, name_len;
5858 int ret = 0;
5859
5860 uinfo = u64_to_user_ptr(attr->info.info);
5861 uinfo_len = attr->info.info_len;
5862
5863 info_copy = min_t(u32, uinfo_len, sizeof(info));
5864 memset(&info, 0, sizeof(info));
5865 if (copy_from_user(&info, uinfo, info_copy))
5866 return -EFAULT;
5867
5868 info.id = btf->id;
5869 ubtf = u64_to_user_ptr(info.btf);
5870 btf_copy = min_t(u32, btf->data_size, info.btf_size);
5871 if (copy_to_user(ubtf, btf->data, btf_copy))
5872 return -EFAULT;
5873 info.btf_size = btf->data_size;
5874
5875 info.kernel_btf = btf->kernel_btf;
5876
5877 uname = u64_to_user_ptr(info.name);
5878 uname_len = info.name_len;
5879 if (!uname ^ !uname_len)
5880 return -EINVAL;
5881
5882 name_len = strlen(btf->name);
5883 info.name_len = name_len;
5884
5885 if (uname) {
5886 if (uname_len >= name_len + 1) {
5887 if (copy_to_user(uname, btf->name, name_len + 1))
5888 return -EFAULT;
5889 } else {
5890 char zero = '\0';
5891
5892 if (copy_to_user(uname, btf->name, uname_len - 1))
5893 return -EFAULT;
5894 if (put_user(zero, uname + uname_len - 1))
5895 return -EFAULT;
5896 /* let user-space know about too short buffer */
5897 ret = -ENOSPC;
5898 }
5899 }
5900
5901 if (copy_to_user(uinfo, &info, info_copy) ||
5902 put_user(info_copy, &uattr->info.info_len))
5903 return -EFAULT;
5904
5905 return ret;
5906}
5907
5908int btf_get_fd_by_id(u32 id)
5909{
5910 struct btf *btf;
5911 int fd;
5912
5913 rcu_read_lock();
5914 btf = idr_find(&btf_idr, id);
5915 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
5916 btf = ERR_PTR(-ENOENT);
5917 rcu_read_unlock();
5918
5919 if (IS_ERR(btf))
5920 return PTR_ERR(btf);
5921
5922 fd = __btf_new_fd(btf);
5923 if (fd < 0)
5924 btf_put(btf);
5925
5926 return fd;
5927}
5928
5929u32 btf_obj_id(const struct btf *btf)
5930{
5931 return btf->id;
5932}
5933
5934bool btf_is_kernel(const struct btf *btf)
5935{
5936 return btf->kernel_btf;
5937}
5938
5939bool btf_is_module(const struct btf *btf)
5940{
5941 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
5942}
5943
5944static int btf_id_cmp_func(const void *a, const void *b)
5945{
5946 const int *pa = a, *pb = b;
5947
5948 return *pa - *pb;
5949}
5950
5951bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
5952{
5953 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
5954}
5955
5956#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
5957struct btf_module {
5958 struct list_head list;
5959 struct module *module;
5960 struct btf *btf;
5961 struct bin_attribute *sysfs_attr;
5962};
5963
5964static LIST_HEAD(btf_modules);
5965static DEFINE_MUTEX(btf_module_mutex);
5966
5967static ssize_t
5968btf_module_read(struct file *file, struct kobject *kobj,
5969 struct bin_attribute *bin_attr,
5970 char *buf, loff_t off, size_t len)
5971{
5972 const struct btf *btf = bin_attr->private;
5973
5974 memcpy(buf, btf->data + off, len);
5975 return len;
5976}
5977
5978static int btf_module_notify(struct notifier_block *nb, unsigned long op,
5979 void *module)
5980{
5981 struct btf_module *btf_mod, *tmp;
5982 struct module *mod = module;
5983 struct btf *btf;
5984 int err = 0;
5985
5986 if (mod->btf_data_size == 0 ||
5987 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
5988 goto out;
5989
5990 switch (op) {
5991 case MODULE_STATE_COMING:
5992 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
5993 if (!btf_mod) {
5994 err = -ENOMEM;
5995 goto out;
5996 }
5997 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
5998 if (IS_ERR(btf)) {
5999 pr_warn("failed to validate module [%s] BTF: %ld\n",
6000 mod->name, PTR_ERR(btf));
6001 kfree(btf_mod);
6002 err = PTR_ERR(btf);
6003 goto out;
6004 }
6005 err = btf_alloc_id(btf);
6006 if (err) {
6007 btf_free(btf);
6008 kfree(btf_mod);
6009 goto out;
6010 }
6011
6012 mutex_lock(&btf_module_mutex);
6013 btf_mod->module = module;
6014 btf_mod->btf = btf;
6015 list_add(&btf_mod->list, &btf_modules);
6016 mutex_unlock(&btf_module_mutex);
6017
6018 if (IS_ENABLED(CONFIG_SYSFS)) {
6019 struct bin_attribute *attr;
6020
6021 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
6022 if (!attr)
6023 goto out;
6024
6025 sysfs_bin_attr_init(attr);
6026 attr->attr.name = btf->name;
6027 attr->attr.mode = 0444;
6028 attr->size = btf->data_size;
6029 attr->private = btf;
6030 attr->read = btf_module_read;
6031
6032 err = sysfs_create_bin_file(btf_kobj, attr);
6033 if (err) {
6034 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
6035 mod->name, err);
6036 kfree(attr);
6037 err = 0;
6038 goto out;
6039 }
6040
6041 btf_mod->sysfs_attr = attr;
6042 }
6043
6044 break;
6045 case MODULE_STATE_GOING:
6046 mutex_lock(&btf_module_mutex);
6047 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6048 if (btf_mod->module != module)
6049 continue;
6050
6051 list_del(&btf_mod->list);
6052 if (btf_mod->sysfs_attr)
6053 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
6054 btf_put(btf_mod->btf);
6055 kfree(btf_mod->sysfs_attr);
6056 kfree(btf_mod);
6057 break;
6058 }
6059 mutex_unlock(&btf_module_mutex);
6060 break;
6061 }
6062out:
6063 return notifier_from_errno(err);
6064}
6065
6066static struct notifier_block btf_module_nb = {
6067 .notifier_call = btf_module_notify,
6068};
6069
6070static int __init btf_module_init(void)
6071{
6072 register_module_notifier(&btf_module_nb);
6073 return 0;
6074}
6075
6076fs_initcall(btf_module_init);
6077#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6078
6079struct module *btf_try_get_module(const struct btf *btf)
6080{
6081 struct module *res = NULL;
6082#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6083 struct btf_module *btf_mod, *tmp;
6084
6085 mutex_lock(&btf_module_mutex);
6086 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6087 if (btf_mod->btf != btf)
6088 continue;
6089
6090 if (try_module_get(btf_mod->module))
6091 res = btf_mod->module;
6092
6093 break;
6094 }
6095 mutex_unlock(&btf_module_mutex);
6096#endif
6097
6098 return res;
6099}
6100
6101BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
6102{
6103 struct btf *btf;
6104 long ret;
6105
6106 if (flags)
6107 return -EINVAL;
6108
6109 if (name_sz <= 1 || name[name_sz - 1])
6110 return -EINVAL;
6111
6112 btf = bpf_get_btf_vmlinux();
6113 if (IS_ERR(btf))
6114 return PTR_ERR(btf);
6115
6116 ret = btf_find_by_name_kind(btf, name, kind);
6117 /* ret is never zero, since btf_find_by_name_kind returns
6118 * positive btf_id or negative error.
6119 */
6120 if (ret < 0) {
6121 struct btf *mod_btf;
6122 int id;
6123
6124 /* If name is not found in vmlinux's BTF then search in module's BTFs */
6125 spin_lock_bh(&btf_idr_lock);
6126 idr_for_each_entry(&btf_idr, mod_btf, id) {
6127 if (!btf_is_module(mod_btf))
6128 continue;
6129 /* linear search could be slow hence unlock/lock
6130 * the IDR to avoiding holding it for too long
6131 */
6132 btf_get(mod_btf);
6133 spin_unlock_bh(&btf_idr_lock);
6134 ret = btf_find_by_name_kind(mod_btf, name, kind);
6135 if (ret > 0) {
6136 int btf_obj_fd;
6137
6138 btf_obj_fd = __btf_new_fd(mod_btf);
6139 if (btf_obj_fd < 0) {
6140 btf_put(mod_btf);
6141 return btf_obj_fd;
6142 }
6143 return ret | (((u64)btf_obj_fd) << 32);
6144 }
6145 spin_lock_bh(&btf_idr_lock);
6146 btf_put(mod_btf);
6147 }
6148 spin_unlock_bh(&btf_idr_lock);
6149 }
6150 return ret;
6151}
6152
6153const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
6154 .func = bpf_btf_find_by_name_kind,
6155 .gpl_only = false,
6156 .ret_type = RET_INTEGER,
6157 .arg1_type = ARG_PTR_TO_MEM,
6158 .arg2_type = ARG_CONST_SIZE,
6159 .arg3_type = ARG_ANYTHING,
6160 .arg4_type = ARG_ANYTHING,
6161};