1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2018 Facebook */
3
4 #include <uapi/linux/btf.h>
5 #include <uapi/linux/bpf.h>
6 #include <uapi/linux/bpf_perf_event.h>
7 #include <uapi/linux/types.h>
8 #include <linux/seq_file.h>
9 #include <linux/compiler.h>
10 #include <linux/ctype.h>
11 #include <linux/errno.h>
12 #include <linux/slab.h>
13 #include <linux/anon_inodes.h>
14 #include <linux/file.h>
15 #include <linux/uaccess.h>
16 #include <linux/kernel.h>
17 #include <linux/idr.h>
18 #include <linux/sort.h>
19 #include <linux/bpf_verifier.h>
20 #include <linux/btf.h>
21 #include <linux/btf_ids.h>
22 #include <linux/bpf.h>
23 #include <linux/bpf_lsm.h>
24 #include <linux/skmsg.h>
25 #include <linux/perf_event.h>
26 #include <linux/bsearch.h>
27 #include <linux/kobject.h>
28 #include <linux/sysfs.h>
29
30 #include <net/netfilter/nf_bpf_link.h>
31
32 #include <net/sock.h>
33 #include <net/xdp.h>
34 #include "../tools/lib/bpf/relo_core.h"
35
36 /* BTF (BPF Type Format) is the meta data format which describes
37 * the data types of BPF program/map. Hence, it basically focus
38 * on the C programming language which the modern BPF is primary
39 * using.
40 *
41 * ELF Section:
42 * ~~~~~~~~~~~
43 * The BTF data is stored under the ".BTF" ELF section
44 *
45 * struct btf_type:
46 * ~~~~~~~~~~~~~~~
47 * Each 'struct btf_type' object describes a C data type.
48 * Depending on the type it is describing, a 'struct btf_type'
49 * object may be followed by more data. F.e.
50 * To describe an array, 'struct btf_type' is followed by
51 * 'struct btf_array'.
52 *
53 * 'struct btf_type' and any extra data following it are
54 * 4 bytes aligned.
55 *
56 * Type section:
57 * ~~~~~~~~~~~~~
58 * The BTF type section contains a list of 'struct btf_type' objects.
59 * Each one describes a C type. Recall from the above section
60 * that a 'struct btf_type' object could be immediately followed by extra
61 * data in order to describe some particular C types.
62 *
63 * type_id:
64 * ~~~~~~~
65 * Each btf_type object is identified by a type_id. The type_id
66 * is implicitly implied by the location of the btf_type object in
67 * the BTF type section. The first one has type_id 1. The second
68 * one has type_id 2...etc. Hence, an earlier btf_type has
69 * a smaller type_id.
70 *
71 * A btf_type object may refer to another btf_type object by using
72 * type_id (i.e. the "type" in the "struct btf_type").
73 *
74 * NOTE that we cannot assume any reference-order.
75 * A btf_type object can refer to an earlier btf_type object
76 * but it can also refer to a later btf_type object.
77 *
78 * For example, to describe "const void *". A btf_type
79 * object describing "const" may refer to another btf_type
80 * object describing "void *". This type-reference is done
81 * by specifying type_id:
82 *
83 * [1] CONST (anon) type_id=2
84 * [2] PTR (anon) type_id=0
85 *
86 * The above is the btf_verifier debug log:
87 * - Each line started with "[?]" is a btf_type object
88 * - [?] is the type_id of the btf_type object.
89 * - CONST/PTR is the BTF_KIND_XXX
90 * - "(anon)" is the name of the type. It just
91 * happens that CONST and PTR has no name.
92 * - type_id=XXX is the 'u32 type' in btf_type
93 *
94 * NOTE: "void" has type_id 0
95 *
96 * String section:
97 * ~~~~~~~~~~~~~~
98 * The BTF string section contains the names used by the type section.
99 * Each string is referred by an "offset" from the beginning of the
100 * string section.
101 *
102 * Each string is '\0' terminated.
103 *
104 * The first character in the string section must be '\0'
105 * which is used to mean 'anonymous'. Some btf_type may not
106 * have a name.
107 */
108
109 /* BTF verification:
110 *
111 * To verify BTF data, two passes are needed.
112 *
113 * Pass #1
114 * ~~~~~~~
115 * The first pass is to collect all btf_type objects to
116 * an array: "btf->types".
117 *
118 * Depending on the C type that a btf_type is describing,
119 * a btf_type may be followed by extra data. We don't know
120 * how many btf_type is there, and more importantly we don't
121 * know where each btf_type is located in the type section.
122 *
123 * Without knowing the location of each type_id, most verifications
124 * cannot be done. e.g. an earlier btf_type may refer to a later
125 * btf_type (recall the "const void *" above), so we cannot
126 * check this type-reference in the first pass.
127 *
128 * In the first pass, it still does some verifications (e.g.
129 * checking the name is a valid offset to the string section).
130 *
131 * Pass #2
132 * ~~~~~~~
133 * The main focus is to resolve a btf_type that is referring
134 * to another type.
135 *
136 * We have to ensure the referring type:
137 * 1) does exist in the BTF (i.e. in btf->types[])
138 * 2) does not cause a loop:
139 * struct A {
140 * struct B b;
141 * };
142 *
143 * struct B {
144 * struct A a;
145 * };
146 *
147 * btf_type_needs_resolve() decides if a btf_type needs
148 * to be resolved.
149 *
150 * The needs_resolve type implements the "resolve()" ops which
151 * essentially does a DFS and detects backedge.
152 *
153 * During resolve (or DFS), different C types have different
154 * "RESOLVED" conditions.
155 *
156 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
157 * members because a member is always referring to another
158 * type. A struct's member can be treated as "RESOLVED" if
159 * it is referring to a BTF_KIND_PTR. Otherwise, the
160 * following valid C struct would be rejected:
161 *
162 * struct A {
163 * int m;
164 * struct A *a;
165 * };
166 *
167 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
168 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
169 * detect a pointer loop, e.g.:
170 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
171 * ^ |
172 * +-----------------------------------------+
173 *
174 */
175
176 #define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
177 #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
178 #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
179 #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
180 #define BITS_ROUNDUP_BYTES(bits) \
181 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
182
183 #define BTF_INFO_MASK 0x9f00ffff
184 #define BTF_INT_MASK 0x0fffffff
185 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
186 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
187
188 /* 16MB for 64k structs and each has 16 members and
189 * a few MB spaces for the string section.
190 * The hard limit is S32_MAX.
191 */
192 #define BTF_MAX_SIZE (16 * 1024 * 1024)
193
194 #define for_each_member_from(i, from, struct_type, member) \
195 for (i = from, member = btf_type_member(struct_type) + from; \
196 i < btf_type_vlen(struct_type); \
197 i++, member++)
198
199 #define for_each_vsi_from(i, from, struct_type, member) \
200 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
201 i < btf_type_vlen(struct_type); \
202 i++, member++)
203
204 DEFINE_IDR(btf_idr);
205 DEFINE_SPINLOCK(btf_idr_lock);
206
207 enum btf_kfunc_hook {
208 BTF_KFUNC_HOOK_COMMON,
209 BTF_KFUNC_HOOK_XDP,
210 BTF_KFUNC_HOOK_TC,
211 BTF_KFUNC_HOOK_STRUCT_OPS,
212 BTF_KFUNC_HOOK_TRACING,
213 BTF_KFUNC_HOOK_SYSCALL,
214 BTF_KFUNC_HOOK_FMODRET,
215 BTF_KFUNC_HOOK_CGROUP,
216 BTF_KFUNC_HOOK_SCHED_ACT,
217 BTF_KFUNC_HOOK_SK_SKB,
218 BTF_KFUNC_HOOK_SOCKET_FILTER,
219 BTF_KFUNC_HOOK_LWT,
220 BTF_KFUNC_HOOK_NETFILTER,
221 BTF_KFUNC_HOOK_KPROBE,
222 BTF_KFUNC_HOOK_MAX,
223 };
224
225 enum {
226 BTF_KFUNC_SET_MAX_CNT = 256,
227 BTF_DTOR_KFUNC_MAX_CNT = 256,
228 BTF_KFUNC_FILTER_MAX_CNT = 16,
229 };
230
231 struct btf_kfunc_hook_filter {
232 btf_kfunc_filter_t filters[BTF_KFUNC_FILTER_MAX_CNT];
233 u32 nr_filters;
234 };
235
236 struct btf_kfunc_set_tab {
237 struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
238 struct btf_kfunc_hook_filter hook_filters[BTF_KFUNC_HOOK_MAX];
239 };
240
241 struct btf_id_dtor_kfunc_tab {
242 u32 cnt;
243 struct btf_id_dtor_kfunc dtors[];
244 };
245
246 struct btf_struct_ops_tab {
247 u32 cnt;
248 u32 capacity;
249 struct bpf_struct_ops_desc ops[];
250 };
251
252 struct btf {
253 void *data;
254 struct btf_type **types;
255 u32 *resolved_ids;
256 u32 *resolved_sizes;
257 const char *strings;
258 void *nohdr_data;
259 struct btf_header hdr;
260 u32 nr_types; /* includes VOID for base BTF */
261 u32 types_size;
262 u32 data_size;
263 refcount_t refcnt;
264 u32 id;
265 struct rcu_head rcu;
266 struct btf_kfunc_set_tab *kfunc_set_tab;
267 struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
268 struct btf_struct_metas *struct_meta_tab;
269 struct btf_struct_ops_tab *struct_ops_tab;
270
271 /* split BTF support */
272 struct btf *base_btf;
273 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
274 u32 start_str_off; /* first string offset (0 for base BTF) */
275 char name[MODULE_NAME_LEN];
276 bool kernel_btf;
277 __u32 *base_id_map; /* map from distilled base BTF -> vmlinux BTF ids */
278 };
279
280 enum verifier_phase {
281 CHECK_META,
282 CHECK_TYPE,
283 };
284
285 struct resolve_vertex {
286 const struct btf_type *t;
287 u32 type_id;
288 u16 next_member;
289 };
290
291 enum visit_state {
292 NOT_VISITED,
293 VISITED,
294 RESOLVED,
295 };
296
297 enum resolve_mode {
298 RESOLVE_TBD, /* To Be Determined */
299 RESOLVE_PTR, /* Resolving for Pointer */
300 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
301 * or array
302 */
303 };
304
305 #define MAX_RESOLVE_DEPTH 32
306
307 struct btf_sec_info {
308 u32 off;
309 u32 len;
310 };
311
312 struct btf_verifier_env {
313 struct btf *btf;
314 u8 *visit_states;
315 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
316 struct bpf_verifier_log log;
317 u32 log_type_id;
318 u32 top_stack;
319 enum verifier_phase phase;
320 enum resolve_mode resolve_mode;
321 };
322
323 static const char * const btf_kind_str[NR_BTF_KINDS] = {
324 [BTF_KIND_UNKN] = "UNKNOWN",
325 [BTF_KIND_INT] = "INT",
326 [BTF_KIND_PTR] = "PTR",
327 [BTF_KIND_ARRAY] = "ARRAY",
328 [BTF_KIND_STRUCT] = "STRUCT",
329 [BTF_KIND_UNION] = "UNION",
330 [BTF_KIND_ENUM] = "ENUM",
331 [BTF_KIND_FWD] = "FWD",
332 [BTF_KIND_TYPEDEF] = "TYPEDEF",
333 [BTF_KIND_VOLATILE] = "VOLATILE",
334 [BTF_KIND_CONST] = "CONST",
335 [BTF_KIND_RESTRICT] = "RESTRICT",
336 [BTF_KIND_FUNC] = "FUNC",
337 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
338 [BTF_KIND_VAR] = "VAR",
339 [BTF_KIND_DATASEC] = "DATASEC",
340 [BTF_KIND_FLOAT] = "FLOAT",
341 [BTF_KIND_DECL_TAG] = "DECL_TAG",
342 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
343 [BTF_KIND_ENUM64] = "ENUM64",
344 };
345
btf_type_str(const struct btf_type * t)346 const char *btf_type_str(const struct btf_type *t)
347 {
348 return btf_kind_str[BTF_INFO_KIND(t->info)];
349 }
350
351 /* Chunk size we use in safe copy of data to be shown. */
352 #define BTF_SHOW_OBJ_SAFE_SIZE 32
353
354 /*
355 * This is the maximum size of a base type value (equivalent to a
356 * 128-bit int); if we are at the end of our safe buffer and have
357 * less than 16 bytes space we can't be assured of being able
358 * to copy the next type safely, so in such cases we will initiate
359 * a new copy.
360 */
361 #define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
362
363 /* Type name size */
364 #define BTF_SHOW_NAME_SIZE 80
365
366 /*
367 * The suffix of a type that indicates it cannot alias another type when
368 * comparing BTF IDs for kfunc invocations.
369 */
370 #define NOCAST_ALIAS_SUFFIX "___init"
371
372 /*
373 * Common data to all BTF show operations. Private show functions can add
374 * their own data to a structure containing a struct btf_show and consult it
375 * in the show callback. See btf_type_show() below.
376 *
377 * One challenge with showing nested data is we want to skip 0-valued
378 * data, but in order to figure out whether a nested object is all zeros
379 * we need to walk through it. As a result, we need to make two passes
380 * when handling structs, unions and arrays; the first path simply looks
381 * for nonzero data, while the second actually does the display. The first
382 * pass is signalled by show->state.depth_check being set, and if we
383 * encounter a non-zero value we set show->state.depth_to_show to
384 * the depth at which we encountered it. When we have completed the
385 * first pass, we will know if anything needs to be displayed if
386 * depth_to_show > depth. See btf_[struct,array]_show() for the
387 * implementation of this.
388 *
389 * Another problem is we want to ensure the data for display is safe to
390 * access. To support this, the anonymous "struct {} obj" tracks the data
391 * object and our safe copy of it. We copy portions of the data needed
392 * to the object "copy" buffer, but because its size is limited to
393 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
394 * traverse larger objects for display.
395 *
396 * The various data type show functions all start with a call to
397 * btf_show_start_type() which returns a pointer to the safe copy
398 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
399 * raw data itself). btf_show_obj_safe() is responsible for
400 * using copy_from_kernel_nofault() to update the safe data if necessary
401 * as we traverse the object's data. skbuff-like semantics are
402 * used:
403 *
404 * - obj.head points to the start of the toplevel object for display
405 * - obj.size is the size of the toplevel object
406 * - obj.data points to the current point in the original data at
407 * which our safe data starts. obj.data will advance as we copy
408 * portions of the data.
409 *
410 * In most cases a single copy will suffice, but larger data structures
411 * such as "struct task_struct" will require many copies. The logic in
412 * btf_show_obj_safe() handles the logic that determines if a new
413 * copy_from_kernel_nofault() is needed.
414 */
415 struct btf_show {
416 u64 flags;
417 void *target; /* target of show operation (seq file, buffer) */
418 __printf(2, 0) void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
419 const struct btf *btf;
420 /* below are used during iteration */
421 struct {
422 u8 depth;
423 u8 depth_to_show;
424 u8 depth_check;
425 u8 array_member:1,
426 array_terminated:1;
427 u16 array_encoding;
428 u32 type_id;
429 int status; /* non-zero for error */
430 const struct btf_type *type;
431 const struct btf_member *member;
432 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
433 } state;
434 struct {
435 u32 size;
436 void *head;
437 void *data;
438 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
439 } obj;
440 };
441
442 struct btf_kind_operations {
443 s32 (*check_meta)(struct btf_verifier_env *env,
444 const struct btf_type *t,
445 u32 meta_left);
446 int (*resolve)(struct btf_verifier_env *env,
447 const struct resolve_vertex *v);
448 int (*check_member)(struct btf_verifier_env *env,
449 const struct btf_type *struct_type,
450 const struct btf_member *member,
451 const struct btf_type *member_type);
452 int (*check_kflag_member)(struct btf_verifier_env *env,
453 const struct btf_type *struct_type,
454 const struct btf_member *member,
455 const struct btf_type *member_type);
456 void (*log_details)(struct btf_verifier_env *env,
457 const struct btf_type *t);
458 void (*show)(const struct btf *btf, const struct btf_type *t,
459 u32 type_id, void *data, u8 bits_offsets,
460 struct btf_show *show);
461 };
462
463 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
464 static struct btf_type btf_void;
465
466 static int btf_resolve(struct btf_verifier_env *env,
467 const struct btf_type *t, u32 type_id);
468
469 static int btf_func_check(struct btf_verifier_env *env,
470 const struct btf_type *t);
471
btf_type_is_modifier(const struct btf_type * t)472 static bool btf_type_is_modifier(const struct btf_type *t)
473 {
474 /* Some of them is not strictly a C modifier
475 * but they are grouped into the same bucket
476 * for BTF concern:
477 * A type (t) that refers to another
478 * type through t->type AND its size cannot
479 * be determined without following the t->type.
480 *
481 * ptr does not fall into this bucket
482 * because its size is always sizeof(void *).
483 */
484 switch (BTF_INFO_KIND(t->info)) {
485 case BTF_KIND_TYPEDEF:
486 case BTF_KIND_VOLATILE:
487 case BTF_KIND_CONST:
488 case BTF_KIND_RESTRICT:
489 case BTF_KIND_TYPE_TAG:
490 return true;
491 }
492
493 return false;
494 }
495
btf_type_is_void(const struct btf_type * t)496 bool btf_type_is_void(const struct btf_type *t)
497 {
498 return t == &btf_void;
499 }
500
btf_type_is_fwd(const struct btf_type * t)501 static bool btf_type_is_fwd(const struct btf_type *t)
502 {
503 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
504 }
505
btf_type_is_datasec(const struct btf_type * t)506 static bool btf_type_is_datasec(const struct btf_type *t)
507 {
508 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
509 }
510
btf_type_is_decl_tag(const struct btf_type * t)511 static bool btf_type_is_decl_tag(const struct btf_type *t)
512 {
513 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
514 }
515
btf_type_nosize(const struct btf_type * t)516 static bool btf_type_nosize(const struct btf_type *t)
517 {
518 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
519 btf_type_is_func(t) || btf_type_is_func_proto(t) ||
520 btf_type_is_decl_tag(t);
521 }
522
btf_type_nosize_or_null(const struct btf_type * t)523 static bool btf_type_nosize_or_null(const struct btf_type *t)
524 {
525 return !t || btf_type_nosize(t);
526 }
527
btf_type_is_decl_tag_target(const struct btf_type * t)528 static bool btf_type_is_decl_tag_target(const struct btf_type *t)
529 {
530 return btf_type_is_func(t) || btf_type_is_struct(t) ||
531 btf_type_is_var(t) || btf_type_is_typedef(t);
532 }
533
btf_is_vmlinux(const struct btf * btf)534 bool btf_is_vmlinux(const struct btf *btf)
535 {
536 return btf->kernel_btf && !btf->base_btf;
537 }
538
btf_nr_types(const struct btf * btf)539 u32 btf_nr_types(const struct btf *btf)
540 {
541 u32 total = 0;
542
543 while (btf) {
544 total += btf->nr_types;
545 btf = btf->base_btf;
546 }
547
548 return total;
549 }
550
btf_find_by_name_kind(const struct btf * btf,const char * name,u8 kind)551 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
552 {
553 const struct btf_type *t;
554 const char *tname;
555 u32 i, total;
556
557 total = btf_nr_types(btf);
558 for (i = 1; i < total; i++) {
559 t = btf_type_by_id(btf, i);
560 if (BTF_INFO_KIND(t->info) != kind)
561 continue;
562
563 tname = btf_name_by_offset(btf, t->name_off);
564 if (!strcmp(tname, name))
565 return i;
566 }
567
568 return -ENOENT;
569 }
570
bpf_find_btf_id(const char * name,u32 kind,struct btf ** btf_p)571 s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
572 {
573 struct btf *btf;
574 s32 ret;
575 int id;
576
577 btf = bpf_get_btf_vmlinux();
578 if (IS_ERR(btf))
579 return PTR_ERR(btf);
580 if (!btf)
581 return -EINVAL;
582
583 ret = btf_find_by_name_kind(btf, name, kind);
584 /* ret is never zero, since btf_find_by_name_kind returns
585 * positive btf_id or negative error.
586 */
587 if (ret > 0) {
588 btf_get(btf);
589 *btf_p = btf;
590 return ret;
591 }
592
593 /* If name is not found in vmlinux's BTF then search in module's BTFs */
594 spin_lock_bh(&btf_idr_lock);
595 idr_for_each_entry(&btf_idr, btf, id) {
596 if (!btf_is_module(btf))
597 continue;
598 /* linear search could be slow hence unlock/lock
599 * the IDR to avoiding holding it for too long
600 */
601 btf_get(btf);
602 spin_unlock_bh(&btf_idr_lock);
603 ret = btf_find_by_name_kind(btf, name, kind);
604 if (ret > 0) {
605 *btf_p = btf;
606 return ret;
607 }
608 btf_put(btf);
609 spin_lock_bh(&btf_idr_lock);
610 }
611 spin_unlock_bh(&btf_idr_lock);
612 return ret;
613 }
614
btf_type_skip_modifiers(const struct btf * btf,u32 id,u32 * res_id)615 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
616 u32 id, u32 *res_id)
617 {
618 const struct btf_type *t = btf_type_by_id(btf, id);
619
620 while (btf_type_is_modifier(t)) {
621 id = t->type;
622 t = btf_type_by_id(btf, t->type);
623 }
624
625 if (res_id)
626 *res_id = id;
627
628 return t;
629 }
630
btf_type_resolve_ptr(const struct btf * btf,u32 id,u32 * res_id)631 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
632 u32 id, u32 *res_id)
633 {
634 const struct btf_type *t;
635
636 t = btf_type_skip_modifiers(btf, id, NULL);
637 if (!btf_type_is_ptr(t))
638 return NULL;
639
640 return btf_type_skip_modifiers(btf, t->type, res_id);
641 }
642
btf_type_resolve_func_ptr(const struct btf * btf,u32 id,u32 * res_id)643 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
644 u32 id, u32 *res_id)
645 {
646 const struct btf_type *ptype;
647
648 ptype = btf_type_resolve_ptr(btf, id, res_id);
649 if (ptype && btf_type_is_func_proto(ptype))
650 return ptype;
651
652 return NULL;
653 }
654
655 /* Types that act only as a source, not sink or intermediate
656 * type when resolving.
657 */
btf_type_is_resolve_source_only(const struct btf_type * t)658 static bool btf_type_is_resolve_source_only(const struct btf_type *t)
659 {
660 return btf_type_is_var(t) ||
661 btf_type_is_decl_tag(t) ||
662 btf_type_is_datasec(t);
663 }
664
665 /* What types need to be resolved?
666 *
667 * btf_type_is_modifier() is an obvious one.
668 *
669 * btf_type_is_struct() because its member refers to
670 * another type (through member->type).
671 *
672 * btf_type_is_var() because the variable refers to
673 * another type. btf_type_is_datasec() holds multiple
674 * btf_type_is_var() types that need resolving.
675 *
676 * btf_type_is_array() because its element (array->type)
677 * refers to another type. Array can be thought of a
678 * special case of struct while array just has the same
679 * member-type repeated by array->nelems of times.
680 */
btf_type_needs_resolve(const struct btf_type * t)681 static bool btf_type_needs_resolve(const struct btf_type *t)
682 {
683 return btf_type_is_modifier(t) ||
684 btf_type_is_ptr(t) ||
685 btf_type_is_struct(t) ||
686 btf_type_is_array(t) ||
687 btf_type_is_var(t) ||
688 btf_type_is_func(t) ||
689 btf_type_is_decl_tag(t) ||
690 btf_type_is_datasec(t);
691 }
692
693 /* t->size can be used */
btf_type_has_size(const struct btf_type * t)694 static bool btf_type_has_size(const struct btf_type *t)
695 {
696 switch (BTF_INFO_KIND(t->info)) {
697 case BTF_KIND_INT:
698 case BTF_KIND_STRUCT:
699 case BTF_KIND_UNION:
700 case BTF_KIND_ENUM:
701 case BTF_KIND_DATASEC:
702 case BTF_KIND_FLOAT:
703 case BTF_KIND_ENUM64:
704 return true;
705 }
706
707 return false;
708 }
709
btf_int_encoding_str(u8 encoding)710 static const char *btf_int_encoding_str(u8 encoding)
711 {
712 if (encoding == 0)
713 return "(none)";
714 else if (encoding == BTF_INT_SIGNED)
715 return "SIGNED";
716 else if (encoding == BTF_INT_CHAR)
717 return "CHAR";
718 else if (encoding == BTF_INT_BOOL)
719 return "BOOL";
720 else
721 return "UNKN";
722 }
723
btf_type_int(const struct btf_type * t)724 static u32 btf_type_int(const struct btf_type *t)
725 {
726 return *(u32 *)(t + 1);
727 }
728
btf_type_array(const struct btf_type * t)729 static const struct btf_array *btf_type_array(const struct btf_type *t)
730 {
731 return (const struct btf_array *)(t + 1);
732 }
733
btf_type_enum(const struct btf_type * t)734 static const struct btf_enum *btf_type_enum(const struct btf_type *t)
735 {
736 return (const struct btf_enum *)(t + 1);
737 }
738
btf_type_var(const struct btf_type * t)739 static const struct btf_var *btf_type_var(const struct btf_type *t)
740 {
741 return (const struct btf_var *)(t + 1);
742 }
743
btf_type_decl_tag(const struct btf_type * t)744 static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
745 {
746 return (const struct btf_decl_tag *)(t + 1);
747 }
748
btf_type_enum64(const struct btf_type * t)749 static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
750 {
751 return (const struct btf_enum64 *)(t + 1);
752 }
753
btf_type_ops(const struct btf_type * t)754 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
755 {
756 return kind_ops[BTF_INFO_KIND(t->info)];
757 }
758
btf_name_offset_valid(const struct btf * btf,u32 offset)759 static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
760 {
761 if (!BTF_STR_OFFSET_VALID(offset))
762 return false;
763
764 while (offset < btf->start_str_off)
765 btf = btf->base_btf;
766
767 offset -= btf->start_str_off;
768 return offset < btf->hdr.str_len;
769 }
770
__btf_name_char_ok(char c,bool first)771 static bool __btf_name_char_ok(char c, bool first)
772 {
773 if ((first ? !isalpha(c) :
774 !isalnum(c)) &&
775 c != '_' &&
776 c != '.')
777 return false;
778 return true;
779 }
780
btf_str_by_offset(const struct btf * btf,u32 offset)781 const char *btf_str_by_offset(const struct btf *btf, u32 offset)
782 {
783 while (offset < btf->start_str_off)
784 btf = btf->base_btf;
785
786 offset -= btf->start_str_off;
787 if (offset < btf->hdr.str_len)
788 return &btf->strings[offset];
789
790 return NULL;
791 }
792
btf_name_valid_identifier(const struct btf * btf,u32 offset)793 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
794 {
795 /* offset must be valid */
796 const char *src = btf_str_by_offset(btf, offset);
797 const char *src_limit;
798
799 if (!__btf_name_char_ok(*src, true))
800 return false;
801
802 /* set a limit on identifier length */
803 src_limit = src + KSYM_NAME_LEN;
804 src++;
805 while (*src && src < src_limit) {
806 if (!__btf_name_char_ok(*src, false))
807 return false;
808 src++;
809 }
810
811 return !*src;
812 }
813
814 /* Allow any printable character in DATASEC names */
btf_name_valid_section(const struct btf * btf,u32 offset)815 static bool btf_name_valid_section(const struct btf *btf, u32 offset)
816 {
817 /* offset must be valid */
818 const char *src = btf_str_by_offset(btf, offset);
819 const char *src_limit;
820
821 if (!*src)
822 return false;
823
824 /* set a limit on identifier length */
825 src_limit = src + KSYM_NAME_LEN;
826 while (*src && src < src_limit) {
827 if (!isprint(*src))
828 return false;
829 src++;
830 }
831
832 return !*src;
833 }
834
__btf_name_by_offset(const struct btf * btf,u32 offset)835 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
836 {
837 const char *name;
838
839 if (!offset)
840 return "(anon)";
841
842 name = btf_str_by_offset(btf, offset);
843 return name ?: "(invalid-name-offset)";
844 }
845
btf_name_by_offset(const struct btf * btf,u32 offset)846 const char *btf_name_by_offset(const struct btf *btf, u32 offset)
847 {
848 return btf_str_by_offset(btf, offset);
849 }
850
btf_type_by_id(const struct btf * btf,u32 type_id)851 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
852 {
853 while (type_id < btf->start_id)
854 btf = btf->base_btf;
855
856 type_id -= btf->start_id;
857 if (type_id >= btf->nr_types)
858 return NULL;
859 return btf->types[type_id];
860 }
861 EXPORT_SYMBOL_GPL(btf_type_by_id);
862
863 /*
864 * Regular int is not a bit field and it must be either
865 * u8/u16/u32/u64 or __int128.
866 */
btf_type_int_is_regular(const struct btf_type * t)867 static bool btf_type_int_is_regular(const struct btf_type *t)
868 {
869 u8 nr_bits, nr_bytes;
870 u32 int_data;
871
872 int_data = btf_type_int(t);
873 nr_bits = BTF_INT_BITS(int_data);
874 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
875 if (BITS_PER_BYTE_MASKED(nr_bits) ||
876 BTF_INT_OFFSET(int_data) ||
877 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
878 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
879 nr_bytes != (2 * sizeof(u64)))) {
880 return false;
881 }
882
883 return true;
884 }
885
886 /*
887 * Check that given struct member is a regular int with expected
888 * offset and size.
889 */
btf_member_is_reg_int(const struct btf * btf,const struct btf_type * s,const struct btf_member * m,u32 expected_offset,u32 expected_size)890 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
891 const struct btf_member *m,
892 u32 expected_offset, u32 expected_size)
893 {
894 const struct btf_type *t;
895 u32 id, int_data;
896 u8 nr_bits;
897
898 id = m->type;
899 t = btf_type_id_size(btf, &id, NULL);
900 if (!t || !btf_type_is_int(t))
901 return false;
902
903 int_data = btf_type_int(t);
904 nr_bits = BTF_INT_BITS(int_data);
905 if (btf_type_kflag(s)) {
906 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
907 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
908
909 /* if kflag set, int should be a regular int and
910 * bit offset should be at byte boundary.
911 */
912 return !bitfield_size &&
913 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
914 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
915 }
916
917 if (BTF_INT_OFFSET(int_data) ||
918 BITS_PER_BYTE_MASKED(m->offset) ||
919 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
920 BITS_PER_BYTE_MASKED(nr_bits) ||
921 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
922 return false;
923
924 return true;
925 }
926
927 /* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
btf_type_skip_qualifiers(const struct btf * btf,u32 id)928 static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
929 u32 id)
930 {
931 const struct btf_type *t = btf_type_by_id(btf, id);
932
933 while (btf_type_is_modifier(t) &&
934 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
935 t = btf_type_by_id(btf, t->type);
936 }
937
938 return t;
939 }
940
941 #define BTF_SHOW_MAX_ITER 10
942
943 #define BTF_KIND_BIT(kind) (1ULL << kind)
944
945 /*
946 * Populate show->state.name with type name information.
947 * Format of type name is
948 *
949 * [.member_name = ] (type_name)
950 */
btf_show_name(struct btf_show * show)951 static const char *btf_show_name(struct btf_show *show)
952 {
953 /* BTF_MAX_ITER array suffixes "[]" */
954 const char *array_suffixes = "[][][][][][][][][][]";
955 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
956 /* BTF_MAX_ITER pointer suffixes "*" */
957 const char *ptr_suffixes = "**********";
958 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
959 const char *name = NULL, *prefix = "", *parens = "";
960 const struct btf_member *m = show->state.member;
961 const struct btf_type *t;
962 const struct btf_array *array;
963 u32 id = show->state.type_id;
964 const char *member = NULL;
965 bool show_member = false;
966 u64 kinds = 0;
967 int i;
968
969 show->state.name[0] = '\0';
970
971 /*
972 * Don't show type name if we're showing an array member;
973 * in that case we show the array type so don't need to repeat
974 * ourselves for each member.
975 */
976 if (show->state.array_member)
977 return "";
978
979 /* Retrieve member name, if any. */
980 if (m) {
981 member = btf_name_by_offset(show->btf, m->name_off);
982 show_member = strlen(member) > 0;
983 id = m->type;
984 }
985
986 /*
987 * Start with type_id, as we have resolved the struct btf_type *
988 * via btf_modifier_show() past the parent typedef to the child
989 * struct, int etc it is defined as. In such cases, the type_id
990 * still represents the starting type while the struct btf_type *
991 * in our show->state points at the resolved type of the typedef.
992 */
993 t = btf_type_by_id(show->btf, id);
994 if (!t)
995 return "";
996
997 /*
998 * The goal here is to build up the right number of pointer and
999 * array suffixes while ensuring the type name for a typedef
1000 * is represented. Along the way we accumulate a list of
1001 * BTF kinds we have encountered, since these will inform later
1002 * display; for example, pointer types will not require an
1003 * opening "{" for struct, we will just display the pointer value.
1004 *
1005 * We also want to accumulate the right number of pointer or array
1006 * indices in the format string while iterating until we get to
1007 * the typedef/pointee/array member target type.
1008 *
1009 * We start by pointing at the end of pointer and array suffix
1010 * strings; as we accumulate pointers and arrays we move the pointer
1011 * or array string backwards so it will show the expected number of
1012 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
1013 * and/or arrays and typedefs are supported as a precaution.
1014 *
1015 * We also want to get typedef name while proceeding to resolve
1016 * type it points to so that we can add parentheses if it is a
1017 * "typedef struct" etc.
1018 */
1019 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
1020
1021 switch (BTF_INFO_KIND(t->info)) {
1022 case BTF_KIND_TYPEDEF:
1023 if (!name)
1024 name = btf_name_by_offset(show->btf,
1025 t->name_off);
1026 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
1027 id = t->type;
1028 break;
1029 case BTF_KIND_ARRAY:
1030 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
1031 parens = "[";
1032 if (!t)
1033 return "";
1034 array = btf_type_array(t);
1035 if (array_suffix > array_suffixes)
1036 array_suffix -= 2;
1037 id = array->type;
1038 break;
1039 case BTF_KIND_PTR:
1040 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
1041 if (ptr_suffix > ptr_suffixes)
1042 ptr_suffix -= 1;
1043 id = t->type;
1044 break;
1045 default:
1046 id = 0;
1047 break;
1048 }
1049 if (!id)
1050 break;
1051 t = btf_type_skip_qualifiers(show->btf, id);
1052 }
1053 /* We may not be able to represent this type; bail to be safe */
1054 if (i == BTF_SHOW_MAX_ITER)
1055 return "";
1056
1057 if (!name)
1058 name = btf_name_by_offset(show->btf, t->name_off);
1059
1060 switch (BTF_INFO_KIND(t->info)) {
1061 case BTF_KIND_STRUCT:
1062 case BTF_KIND_UNION:
1063 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1064 "struct" : "union";
1065 /* if it's an array of struct/union, parens is already set */
1066 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1067 parens = "{";
1068 break;
1069 case BTF_KIND_ENUM:
1070 case BTF_KIND_ENUM64:
1071 prefix = "enum";
1072 break;
1073 default:
1074 break;
1075 }
1076
1077 /* pointer does not require parens */
1078 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1079 parens = "";
1080 /* typedef does not require struct/union/enum prefix */
1081 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1082 prefix = "";
1083
1084 if (!name)
1085 name = "";
1086
1087 /* Even if we don't want type name info, we want parentheses etc */
1088 if (show->flags & BTF_SHOW_NONAME)
1089 snprintf(show->state.name, sizeof(show->state.name), "%s",
1090 parens);
1091 else
1092 snprintf(show->state.name, sizeof(show->state.name),
1093 "%s%s%s(%s%s%s%s%s%s)%s",
1094 /* first 3 strings comprise ".member = " */
1095 show_member ? "." : "",
1096 show_member ? member : "",
1097 show_member ? " = " : "",
1098 /* ...next is our prefix (struct, enum, etc) */
1099 prefix,
1100 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1101 /* ...this is the type name itself */
1102 name,
1103 /* ...suffixed by the appropriate '*', '[]' suffixes */
1104 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1105 array_suffix, parens);
1106
1107 return show->state.name;
1108 }
1109
__btf_show_indent(struct btf_show * show)1110 static const char *__btf_show_indent(struct btf_show *show)
1111 {
1112 const char *indents = " ";
1113 const char *indent = &indents[strlen(indents)];
1114
1115 if ((indent - show->state.depth) >= indents)
1116 return indent - show->state.depth;
1117 return indents;
1118 }
1119
btf_show_indent(struct btf_show * show)1120 static const char *btf_show_indent(struct btf_show *show)
1121 {
1122 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1123 }
1124
btf_show_newline(struct btf_show * show)1125 static const char *btf_show_newline(struct btf_show *show)
1126 {
1127 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1128 }
1129
btf_show_delim(struct btf_show * show)1130 static const char *btf_show_delim(struct btf_show *show)
1131 {
1132 if (show->state.depth == 0)
1133 return "";
1134
1135 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1136 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1137 return "|";
1138
1139 return ",";
1140 }
1141
btf_show(struct btf_show * show,const char * fmt,...)1142 __printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1143 {
1144 va_list args;
1145
1146 if (!show->state.depth_check) {
1147 va_start(args, fmt);
1148 show->showfn(show, fmt, args);
1149 va_end(args);
1150 }
1151 }
1152
1153 /* Macros are used here as btf_show_type_value[s]() prepends and appends
1154 * format specifiers to the format specifier passed in; these do the work of
1155 * adding indentation, delimiters etc while the caller simply has to specify
1156 * the type value(s) in the format specifier + value(s).
1157 */
1158 #define btf_show_type_value(show, fmt, value) \
1159 do { \
1160 if ((value) != (__typeof__(value))0 || \
1161 (show->flags & BTF_SHOW_ZERO) || \
1162 show->state.depth == 0) { \
1163 btf_show(show, "%s%s" fmt "%s%s", \
1164 btf_show_indent(show), \
1165 btf_show_name(show), \
1166 value, btf_show_delim(show), \
1167 btf_show_newline(show)); \
1168 if (show->state.depth > show->state.depth_to_show) \
1169 show->state.depth_to_show = show->state.depth; \
1170 } \
1171 } while (0)
1172
1173 #define btf_show_type_values(show, fmt, ...) \
1174 do { \
1175 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1176 btf_show_name(show), \
1177 __VA_ARGS__, btf_show_delim(show), \
1178 btf_show_newline(show)); \
1179 if (show->state.depth > show->state.depth_to_show) \
1180 show->state.depth_to_show = show->state.depth; \
1181 } while (0)
1182
1183 /* How much is left to copy to safe buffer after @data? */
btf_show_obj_size_left(struct btf_show * show,void * data)1184 static int btf_show_obj_size_left(struct btf_show *show, void *data)
1185 {
1186 return show->obj.head + show->obj.size - data;
1187 }
1188
1189 /* Is object pointed to by @data of @size already copied to our safe buffer? */
btf_show_obj_is_safe(struct btf_show * show,void * data,int size)1190 static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1191 {
1192 return data >= show->obj.data &&
1193 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1194 }
1195
1196 /*
1197 * If object pointed to by @data of @size falls within our safe buffer, return
1198 * the equivalent pointer to the same safe data. Assumes
1199 * copy_from_kernel_nofault() has already happened and our safe buffer is
1200 * populated.
1201 */
__btf_show_obj_safe(struct btf_show * show,void * data,int size)1202 static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1203 {
1204 if (btf_show_obj_is_safe(show, data, size))
1205 return show->obj.safe + (data - show->obj.data);
1206 return NULL;
1207 }
1208
1209 /*
1210 * Return a safe-to-access version of data pointed to by @data.
1211 * We do this by copying the relevant amount of information
1212 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1213 *
1214 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1215 * safe copy is needed.
1216 *
1217 * Otherwise we need to determine if we have the required amount
1218 * of data (determined by the @data pointer and the size of the
1219 * largest base type we can encounter (represented by
1220 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1221 * that we will be able to print some of the current object,
1222 * and if more is needed a copy will be triggered.
1223 * Some objects such as structs will not fit into the buffer;
1224 * in such cases additional copies when we iterate over their
1225 * members may be needed.
1226 *
1227 * btf_show_obj_safe() is used to return a safe buffer for
1228 * btf_show_start_type(); this ensures that as we recurse into
1229 * nested types we always have safe data for the given type.
1230 * This approach is somewhat wasteful; it's possible for example
1231 * that when iterating over a large union we'll end up copying the
1232 * same data repeatedly, but the goal is safety not performance.
1233 * We use stack data as opposed to per-CPU buffers because the
1234 * iteration over a type can take some time, and preemption handling
1235 * would greatly complicate use of the safe buffer.
1236 */
btf_show_obj_safe(struct btf_show * show,const struct btf_type * t,void * data)1237 static void *btf_show_obj_safe(struct btf_show *show,
1238 const struct btf_type *t,
1239 void *data)
1240 {
1241 const struct btf_type *rt;
1242 int size_left, size;
1243 void *safe = NULL;
1244
1245 if (show->flags & BTF_SHOW_UNSAFE)
1246 return data;
1247
1248 rt = btf_resolve_size(show->btf, t, &size);
1249 if (IS_ERR(rt)) {
1250 show->state.status = PTR_ERR(rt);
1251 return NULL;
1252 }
1253
1254 /*
1255 * Is this toplevel object? If so, set total object size and
1256 * initialize pointers. Otherwise check if we still fall within
1257 * our safe object data.
1258 */
1259 if (show->state.depth == 0) {
1260 show->obj.size = size;
1261 show->obj.head = data;
1262 } else {
1263 /*
1264 * If the size of the current object is > our remaining
1265 * safe buffer we _may_ need to do a new copy. However
1266 * consider the case of a nested struct; it's size pushes
1267 * us over the safe buffer limit, but showing any individual
1268 * struct members does not. In such cases, we don't need
1269 * to initiate a fresh copy yet; however we definitely need
1270 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1271 * in our buffer, regardless of the current object size.
1272 * The logic here is that as we resolve types we will
1273 * hit a base type at some point, and we need to be sure
1274 * the next chunk of data is safely available to display
1275 * that type info safely. We cannot rely on the size of
1276 * the current object here because it may be much larger
1277 * than our current buffer (e.g. task_struct is 8k).
1278 * All we want to do here is ensure that we can print the
1279 * next basic type, which we can if either
1280 * - the current type size is within the safe buffer; or
1281 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1282 * the safe buffer.
1283 */
1284 safe = __btf_show_obj_safe(show, data,
1285 min(size,
1286 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1287 }
1288
1289 /*
1290 * We need a new copy to our safe object, either because we haven't
1291 * yet copied and are initializing safe data, or because the data
1292 * we want falls outside the boundaries of the safe object.
1293 */
1294 if (!safe) {
1295 size_left = btf_show_obj_size_left(show, data);
1296 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1297 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1298 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1299 data, size_left);
1300 if (!show->state.status) {
1301 show->obj.data = data;
1302 safe = show->obj.safe;
1303 }
1304 }
1305
1306 return safe;
1307 }
1308
1309 /*
1310 * Set the type we are starting to show and return a safe data pointer
1311 * to be used for showing the associated data.
1312 */
btf_show_start_type(struct btf_show * show,const struct btf_type * t,u32 type_id,void * data)1313 static void *btf_show_start_type(struct btf_show *show,
1314 const struct btf_type *t,
1315 u32 type_id, void *data)
1316 {
1317 show->state.type = t;
1318 show->state.type_id = type_id;
1319 show->state.name[0] = '\0';
1320
1321 return btf_show_obj_safe(show, t, data);
1322 }
1323
btf_show_end_type(struct btf_show * show)1324 static void btf_show_end_type(struct btf_show *show)
1325 {
1326 show->state.type = NULL;
1327 show->state.type_id = 0;
1328 show->state.name[0] = '\0';
1329 }
1330
btf_show_start_aggr_type(struct btf_show * show,const struct btf_type * t,u32 type_id,void * data)1331 static void *btf_show_start_aggr_type(struct btf_show *show,
1332 const struct btf_type *t,
1333 u32 type_id, void *data)
1334 {
1335 void *safe_data = btf_show_start_type(show, t, type_id, data);
1336
1337 if (!safe_data)
1338 return safe_data;
1339
1340 btf_show(show, "%s%s%s", btf_show_indent(show),
1341 btf_show_name(show),
1342 btf_show_newline(show));
1343 show->state.depth++;
1344 return safe_data;
1345 }
1346
btf_show_end_aggr_type(struct btf_show * show,const char * suffix)1347 static void btf_show_end_aggr_type(struct btf_show *show,
1348 const char *suffix)
1349 {
1350 show->state.depth--;
1351 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1352 btf_show_delim(show), btf_show_newline(show));
1353 btf_show_end_type(show);
1354 }
1355
btf_show_start_member(struct btf_show * show,const struct btf_member * m)1356 static void btf_show_start_member(struct btf_show *show,
1357 const struct btf_member *m)
1358 {
1359 show->state.member = m;
1360 }
1361
btf_show_start_array_member(struct btf_show * show)1362 static void btf_show_start_array_member(struct btf_show *show)
1363 {
1364 show->state.array_member = 1;
1365 btf_show_start_member(show, NULL);
1366 }
1367
btf_show_end_member(struct btf_show * show)1368 static void btf_show_end_member(struct btf_show *show)
1369 {
1370 show->state.member = NULL;
1371 }
1372
btf_show_end_array_member(struct btf_show * show)1373 static void btf_show_end_array_member(struct btf_show *show)
1374 {
1375 show->state.array_member = 0;
1376 btf_show_end_member(show);
1377 }
1378
btf_show_start_array_type(struct btf_show * show,const struct btf_type * t,u32 type_id,u16 array_encoding,void * data)1379 static void *btf_show_start_array_type(struct btf_show *show,
1380 const struct btf_type *t,
1381 u32 type_id,
1382 u16 array_encoding,
1383 void *data)
1384 {
1385 show->state.array_encoding = array_encoding;
1386 show->state.array_terminated = 0;
1387 return btf_show_start_aggr_type(show, t, type_id, data);
1388 }
1389
btf_show_end_array_type(struct btf_show * show)1390 static void btf_show_end_array_type(struct btf_show *show)
1391 {
1392 show->state.array_encoding = 0;
1393 show->state.array_terminated = 0;
1394 btf_show_end_aggr_type(show, "]");
1395 }
1396
btf_show_start_struct_type(struct btf_show * show,const struct btf_type * t,u32 type_id,void * data)1397 static void *btf_show_start_struct_type(struct btf_show *show,
1398 const struct btf_type *t,
1399 u32 type_id,
1400 void *data)
1401 {
1402 return btf_show_start_aggr_type(show, t, type_id, data);
1403 }
1404
btf_show_end_struct_type(struct btf_show * show)1405 static void btf_show_end_struct_type(struct btf_show *show)
1406 {
1407 btf_show_end_aggr_type(show, "}");
1408 }
1409
__btf_verifier_log(struct bpf_verifier_log * log,const char * fmt,...)1410 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1411 const char *fmt, ...)
1412 {
1413 va_list args;
1414
1415 va_start(args, fmt);
1416 bpf_verifier_vlog(log, fmt, args);
1417 va_end(args);
1418 }
1419
btf_verifier_log(struct btf_verifier_env * env,const char * fmt,...)1420 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1421 const char *fmt, ...)
1422 {
1423 struct bpf_verifier_log *log = &env->log;
1424 va_list args;
1425
1426 if (!bpf_verifier_log_needed(log))
1427 return;
1428
1429 va_start(args, fmt);
1430 bpf_verifier_vlog(log, fmt, args);
1431 va_end(args);
1432 }
1433
__btf_verifier_log_type(struct btf_verifier_env * env,const struct btf_type * t,bool log_details,const char * fmt,...)1434 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1435 const struct btf_type *t,
1436 bool log_details,
1437 const char *fmt, ...)
1438 {
1439 struct bpf_verifier_log *log = &env->log;
1440 struct btf *btf = env->btf;
1441 va_list args;
1442
1443 if (!bpf_verifier_log_needed(log))
1444 return;
1445
1446 if (log->level == BPF_LOG_KERNEL) {
1447 /* btf verifier prints all types it is processing via
1448 * btf_verifier_log_type(..., fmt = NULL).
1449 * Skip those prints for in-kernel BTF verification.
1450 */
1451 if (!fmt)
1452 return;
1453
1454 /* Skip logging when loading module BTF with mismatches permitted */
1455 if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1456 return;
1457 }
1458
1459 __btf_verifier_log(log, "[%u] %s %s%s",
1460 env->log_type_id,
1461 btf_type_str(t),
1462 __btf_name_by_offset(btf, t->name_off),
1463 log_details ? " " : "");
1464
1465 if (log_details)
1466 btf_type_ops(t)->log_details(env, t);
1467
1468 if (fmt && *fmt) {
1469 __btf_verifier_log(log, " ");
1470 va_start(args, fmt);
1471 bpf_verifier_vlog(log, fmt, args);
1472 va_end(args);
1473 }
1474
1475 __btf_verifier_log(log, "\n");
1476 }
1477
1478 #define btf_verifier_log_type(env, t, ...) \
1479 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1480 #define btf_verifier_log_basic(env, t, ...) \
1481 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1482
1483 __printf(4, 5)
btf_verifier_log_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const char * fmt,...)1484 static void btf_verifier_log_member(struct btf_verifier_env *env,
1485 const struct btf_type *struct_type,
1486 const struct btf_member *member,
1487 const char *fmt, ...)
1488 {
1489 struct bpf_verifier_log *log = &env->log;
1490 struct btf *btf = env->btf;
1491 va_list args;
1492
1493 if (!bpf_verifier_log_needed(log))
1494 return;
1495
1496 if (log->level == BPF_LOG_KERNEL) {
1497 if (!fmt)
1498 return;
1499
1500 /* Skip logging when loading module BTF with mismatches permitted */
1501 if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1502 return;
1503 }
1504
1505 /* The CHECK_META phase already did a btf dump.
1506 *
1507 * If member is logged again, it must hit an error in
1508 * parsing this member. It is useful to print out which
1509 * struct this member belongs to.
1510 */
1511 if (env->phase != CHECK_META)
1512 btf_verifier_log_type(env, struct_type, NULL);
1513
1514 if (btf_type_kflag(struct_type))
1515 __btf_verifier_log(log,
1516 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1517 __btf_name_by_offset(btf, member->name_off),
1518 member->type,
1519 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1520 BTF_MEMBER_BIT_OFFSET(member->offset));
1521 else
1522 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1523 __btf_name_by_offset(btf, member->name_off),
1524 member->type, member->offset);
1525
1526 if (fmt && *fmt) {
1527 __btf_verifier_log(log, " ");
1528 va_start(args, fmt);
1529 bpf_verifier_vlog(log, fmt, args);
1530 va_end(args);
1531 }
1532
1533 __btf_verifier_log(log, "\n");
1534 }
1535
1536 __printf(4, 5)
btf_verifier_log_vsi(struct btf_verifier_env * env,const struct btf_type * datasec_type,const struct btf_var_secinfo * vsi,const char * fmt,...)1537 static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1538 const struct btf_type *datasec_type,
1539 const struct btf_var_secinfo *vsi,
1540 const char *fmt, ...)
1541 {
1542 struct bpf_verifier_log *log = &env->log;
1543 va_list args;
1544
1545 if (!bpf_verifier_log_needed(log))
1546 return;
1547 if (log->level == BPF_LOG_KERNEL && !fmt)
1548 return;
1549 if (env->phase != CHECK_META)
1550 btf_verifier_log_type(env, datasec_type, NULL);
1551
1552 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1553 vsi->type, vsi->offset, vsi->size);
1554 if (fmt && *fmt) {
1555 __btf_verifier_log(log, " ");
1556 va_start(args, fmt);
1557 bpf_verifier_vlog(log, fmt, args);
1558 va_end(args);
1559 }
1560
1561 __btf_verifier_log(log, "\n");
1562 }
1563
btf_verifier_log_hdr(struct btf_verifier_env * env,u32 btf_data_size)1564 static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1565 u32 btf_data_size)
1566 {
1567 struct bpf_verifier_log *log = &env->log;
1568 const struct btf *btf = env->btf;
1569 const struct btf_header *hdr;
1570
1571 if (!bpf_verifier_log_needed(log))
1572 return;
1573
1574 if (log->level == BPF_LOG_KERNEL)
1575 return;
1576 hdr = &btf->hdr;
1577 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1578 __btf_verifier_log(log, "version: %u\n", hdr->version);
1579 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1580 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1581 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1582 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1583 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1584 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1585 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1586 }
1587
btf_add_type(struct btf_verifier_env * env,struct btf_type * t)1588 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1589 {
1590 struct btf *btf = env->btf;
1591
1592 if (btf->types_size == btf->nr_types) {
1593 /* Expand 'types' array */
1594
1595 struct btf_type **new_types;
1596 u32 expand_by, new_size;
1597
1598 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1599 btf_verifier_log(env, "Exceeded max num of types");
1600 return -E2BIG;
1601 }
1602
1603 expand_by = max_t(u32, btf->types_size >> 2, 16);
1604 new_size = min_t(u32, BTF_MAX_TYPE,
1605 btf->types_size + expand_by);
1606
1607 new_types = kvcalloc(new_size, sizeof(*new_types),
1608 GFP_KERNEL | __GFP_NOWARN);
1609 if (!new_types)
1610 return -ENOMEM;
1611
1612 if (btf->nr_types == 0) {
1613 if (!btf->base_btf) {
1614 /* lazily init VOID type */
1615 new_types[0] = &btf_void;
1616 btf->nr_types++;
1617 }
1618 } else {
1619 memcpy(new_types, btf->types,
1620 sizeof(*btf->types) * btf->nr_types);
1621 }
1622
1623 kvfree(btf->types);
1624 btf->types = new_types;
1625 btf->types_size = new_size;
1626 }
1627
1628 btf->types[btf->nr_types++] = t;
1629
1630 return 0;
1631 }
1632
btf_alloc_id(struct btf * btf)1633 static int btf_alloc_id(struct btf *btf)
1634 {
1635 int id;
1636
1637 idr_preload(GFP_KERNEL);
1638 spin_lock_bh(&btf_idr_lock);
1639 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1640 if (id > 0)
1641 btf->id = id;
1642 spin_unlock_bh(&btf_idr_lock);
1643 idr_preload_end();
1644
1645 if (WARN_ON_ONCE(!id))
1646 return -ENOSPC;
1647
1648 return id > 0 ? 0 : id;
1649 }
1650
btf_free_id(struct btf * btf)1651 static void btf_free_id(struct btf *btf)
1652 {
1653 unsigned long flags;
1654
1655 /*
1656 * In map-in-map, calling map_delete_elem() on outer
1657 * map will call bpf_map_put on the inner map.
1658 * It will then eventually call btf_free_id()
1659 * on the inner map. Some of the map_delete_elem()
1660 * implementation may have irq disabled, so
1661 * we need to use the _irqsave() version instead
1662 * of the _bh() version.
1663 */
1664 spin_lock_irqsave(&btf_idr_lock, flags);
1665 idr_remove(&btf_idr, btf->id);
1666 spin_unlock_irqrestore(&btf_idr_lock, flags);
1667 }
1668
btf_free_kfunc_set_tab(struct btf * btf)1669 static void btf_free_kfunc_set_tab(struct btf *btf)
1670 {
1671 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1672 int hook;
1673
1674 if (!tab)
1675 return;
1676 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1677 kfree(tab->sets[hook]);
1678 kfree(tab);
1679 btf->kfunc_set_tab = NULL;
1680 }
1681
btf_free_dtor_kfunc_tab(struct btf * btf)1682 static void btf_free_dtor_kfunc_tab(struct btf *btf)
1683 {
1684 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1685
1686 if (!tab)
1687 return;
1688 kfree(tab);
1689 btf->dtor_kfunc_tab = NULL;
1690 }
1691
btf_struct_metas_free(struct btf_struct_metas * tab)1692 static void btf_struct_metas_free(struct btf_struct_metas *tab)
1693 {
1694 int i;
1695
1696 if (!tab)
1697 return;
1698 for (i = 0; i < tab->cnt; i++)
1699 btf_record_free(tab->types[i].record);
1700 kfree(tab);
1701 }
1702
btf_free_struct_meta_tab(struct btf * btf)1703 static void btf_free_struct_meta_tab(struct btf *btf)
1704 {
1705 struct btf_struct_metas *tab = btf->struct_meta_tab;
1706
1707 btf_struct_metas_free(tab);
1708 btf->struct_meta_tab = NULL;
1709 }
1710
btf_free_struct_ops_tab(struct btf * btf)1711 static void btf_free_struct_ops_tab(struct btf *btf)
1712 {
1713 struct btf_struct_ops_tab *tab = btf->struct_ops_tab;
1714 u32 i;
1715
1716 if (!tab)
1717 return;
1718
1719 for (i = 0; i < tab->cnt; i++)
1720 bpf_struct_ops_desc_release(&tab->ops[i]);
1721
1722 kfree(tab);
1723 btf->struct_ops_tab = NULL;
1724 }
1725
btf_free(struct btf * btf)1726 static void btf_free(struct btf *btf)
1727 {
1728 btf_free_struct_meta_tab(btf);
1729 btf_free_dtor_kfunc_tab(btf);
1730 btf_free_kfunc_set_tab(btf);
1731 btf_free_struct_ops_tab(btf);
1732 kvfree(btf->types);
1733 kvfree(btf->resolved_sizes);
1734 kvfree(btf->resolved_ids);
1735 /* vmlinux does not allocate btf->data, it simply points it at
1736 * __start_BTF.
1737 */
1738 if (!btf_is_vmlinux(btf))
1739 kvfree(btf->data);
1740 kvfree(btf->base_id_map);
1741 kfree(btf);
1742 }
1743
btf_free_rcu(struct rcu_head * rcu)1744 static void btf_free_rcu(struct rcu_head *rcu)
1745 {
1746 struct btf *btf = container_of(rcu, struct btf, rcu);
1747
1748 btf_free(btf);
1749 }
1750
btf_get_name(const struct btf * btf)1751 const char *btf_get_name(const struct btf *btf)
1752 {
1753 return btf->name;
1754 }
1755
btf_get(struct btf * btf)1756 void btf_get(struct btf *btf)
1757 {
1758 refcount_inc(&btf->refcnt);
1759 }
1760
btf_put(struct btf * btf)1761 void btf_put(struct btf *btf)
1762 {
1763 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1764 btf_free_id(btf);
1765 call_rcu(&btf->rcu, btf_free_rcu);
1766 }
1767 }
1768
btf_base_btf(const struct btf * btf)1769 struct btf *btf_base_btf(const struct btf *btf)
1770 {
1771 return btf->base_btf;
1772 }
1773
btf_header(const struct btf * btf)1774 const struct btf_header *btf_header(const struct btf *btf)
1775 {
1776 return &btf->hdr;
1777 }
1778
btf_set_base_btf(struct btf * btf,const struct btf * base_btf)1779 void btf_set_base_btf(struct btf *btf, const struct btf *base_btf)
1780 {
1781 btf->base_btf = (struct btf *)base_btf;
1782 btf->start_id = btf_nr_types(base_btf);
1783 btf->start_str_off = base_btf->hdr.str_len;
1784 }
1785
env_resolve_init(struct btf_verifier_env * env)1786 static int env_resolve_init(struct btf_verifier_env *env)
1787 {
1788 struct btf *btf = env->btf;
1789 u32 nr_types = btf->nr_types;
1790 u32 *resolved_sizes = NULL;
1791 u32 *resolved_ids = NULL;
1792 u8 *visit_states = NULL;
1793
1794 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1795 GFP_KERNEL | __GFP_NOWARN);
1796 if (!resolved_sizes)
1797 goto nomem;
1798
1799 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1800 GFP_KERNEL | __GFP_NOWARN);
1801 if (!resolved_ids)
1802 goto nomem;
1803
1804 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1805 GFP_KERNEL | __GFP_NOWARN);
1806 if (!visit_states)
1807 goto nomem;
1808
1809 btf->resolved_sizes = resolved_sizes;
1810 btf->resolved_ids = resolved_ids;
1811 env->visit_states = visit_states;
1812
1813 return 0;
1814
1815 nomem:
1816 kvfree(resolved_sizes);
1817 kvfree(resolved_ids);
1818 kvfree(visit_states);
1819 return -ENOMEM;
1820 }
1821
btf_verifier_env_free(struct btf_verifier_env * env)1822 static void btf_verifier_env_free(struct btf_verifier_env *env)
1823 {
1824 kvfree(env->visit_states);
1825 kfree(env);
1826 }
1827
env_type_is_resolve_sink(const struct btf_verifier_env * env,const struct btf_type * next_type)1828 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1829 const struct btf_type *next_type)
1830 {
1831 switch (env->resolve_mode) {
1832 case RESOLVE_TBD:
1833 /* int, enum or void is a sink */
1834 return !btf_type_needs_resolve(next_type);
1835 case RESOLVE_PTR:
1836 /* int, enum, void, struct, array, func or func_proto is a sink
1837 * for ptr
1838 */
1839 return !btf_type_is_modifier(next_type) &&
1840 !btf_type_is_ptr(next_type);
1841 case RESOLVE_STRUCT_OR_ARRAY:
1842 /* int, enum, void, ptr, func or func_proto is a sink
1843 * for struct and array
1844 */
1845 return !btf_type_is_modifier(next_type) &&
1846 !btf_type_is_array(next_type) &&
1847 !btf_type_is_struct(next_type);
1848 default:
1849 BUG();
1850 }
1851 }
1852
env_type_is_resolved(const struct btf_verifier_env * env,u32 type_id)1853 static bool env_type_is_resolved(const struct btf_verifier_env *env,
1854 u32 type_id)
1855 {
1856 /* base BTF types should be resolved by now */
1857 if (type_id < env->btf->start_id)
1858 return true;
1859
1860 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1861 }
1862
env_stack_push(struct btf_verifier_env * env,const struct btf_type * t,u32 type_id)1863 static int env_stack_push(struct btf_verifier_env *env,
1864 const struct btf_type *t, u32 type_id)
1865 {
1866 const struct btf *btf = env->btf;
1867 struct resolve_vertex *v;
1868
1869 if (env->top_stack == MAX_RESOLVE_DEPTH)
1870 return -E2BIG;
1871
1872 if (type_id < btf->start_id
1873 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1874 return -EEXIST;
1875
1876 env->visit_states[type_id - btf->start_id] = VISITED;
1877
1878 v = &env->stack[env->top_stack++];
1879 v->t = t;
1880 v->type_id = type_id;
1881 v->next_member = 0;
1882
1883 if (env->resolve_mode == RESOLVE_TBD) {
1884 if (btf_type_is_ptr(t))
1885 env->resolve_mode = RESOLVE_PTR;
1886 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1887 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1888 }
1889
1890 return 0;
1891 }
1892
env_stack_set_next_member(struct btf_verifier_env * env,u16 next_member)1893 static void env_stack_set_next_member(struct btf_verifier_env *env,
1894 u16 next_member)
1895 {
1896 env->stack[env->top_stack - 1].next_member = next_member;
1897 }
1898
env_stack_pop_resolved(struct btf_verifier_env * env,u32 resolved_type_id,u32 resolved_size)1899 static void env_stack_pop_resolved(struct btf_verifier_env *env,
1900 u32 resolved_type_id,
1901 u32 resolved_size)
1902 {
1903 u32 type_id = env->stack[--(env->top_stack)].type_id;
1904 struct btf *btf = env->btf;
1905
1906 type_id -= btf->start_id; /* adjust to local type id */
1907 btf->resolved_sizes[type_id] = resolved_size;
1908 btf->resolved_ids[type_id] = resolved_type_id;
1909 env->visit_states[type_id] = RESOLVED;
1910 }
1911
env_stack_peak(struct btf_verifier_env * env)1912 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1913 {
1914 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1915 }
1916
1917 /* Resolve the size of a passed-in "type"
1918 *
1919 * type: is an array (e.g. u32 array[x][y])
1920 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1921 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1922 * corresponds to the return type.
1923 * *elem_type: u32
1924 * *elem_id: id of u32
1925 * *total_nelems: (x * y). Hence, individual elem size is
1926 * (*type_size / *total_nelems)
1927 * *type_id: id of type if it's changed within the function, 0 if not
1928 *
1929 * type: is not an array (e.g. const struct X)
1930 * return type: type "struct X"
1931 * *type_size: sizeof(struct X)
1932 * *elem_type: same as return type ("struct X")
1933 * *elem_id: 0
1934 * *total_nelems: 1
1935 * *type_id: id of type if it's changed within the function, 0 if not
1936 */
1937 static const struct btf_type *
__btf_resolve_size(const struct btf * btf,const struct btf_type * type,u32 * type_size,const struct btf_type ** elem_type,u32 * elem_id,u32 * total_nelems,u32 * type_id)1938 __btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1939 u32 *type_size, const struct btf_type **elem_type,
1940 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1941 {
1942 const struct btf_type *array_type = NULL;
1943 const struct btf_array *array = NULL;
1944 u32 i, size, nelems = 1, id = 0;
1945
1946 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1947 switch (BTF_INFO_KIND(type->info)) {
1948 /* type->size can be used */
1949 case BTF_KIND_INT:
1950 case BTF_KIND_STRUCT:
1951 case BTF_KIND_UNION:
1952 case BTF_KIND_ENUM:
1953 case BTF_KIND_FLOAT:
1954 case BTF_KIND_ENUM64:
1955 size = type->size;
1956 goto resolved;
1957
1958 case BTF_KIND_PTR:
1959 size = sizeof(void *);
1960 goto resolved;
1961
1962 /* Modifiers */
1963 case BTF_KIND_TYPEDEF:
1964 case BTF_KIND_VOLATILE:
1965 case BTF_KIND_CONST:
1966 case BTF_KIND_RESTRICT:
1967 case BTF_KIND_TYPE_TAG:
1968 id = type->type;
1969 type = btf_type_by_id(btf, type->type);
1970 break;
1971
1972 case BTF_KIND_ARRAY:
1973 if (!array_type)
1974 array_type = type;
1975 array = btf_type_array(type);
1976 if (nelems && array->nelems > U32_MAX / nelems)
1977 return ERR_PTR(-EINVAL);
1978 nelems *= array->nelems;
1979 type = btf_type_by_id(btf, array->type);
1980 break;
1981
1982 /* type without size */
1983 default:
1984 return ERR_PTR(-EINVAL);
1985 }
1986 }
1987
1988 return ERR_PTR(-EINVAL);
1989
1990 resolved:
1991 if (nelems && size > U32_MAX / nelems)
1992 return ERR_PTR(-EINVAL);
1993
1994 *type_size = nelems * size;
1995 if (total_nelems)
1996 *total_nelems = nelems;
1997 if (elem_type)
1998 *elem_type = type;
1999 if (elem_id)
2000 *elem_id = array ? array->type : 0;
2001 if (type_id && id)
2002 *type_id = id;
2003
2004 return array_type ? : type;
2005 }
2006
2007 const struct btf_type *
btf_resolve_size(const struct btf * btf,const struct btf_type * type,u32 * type_size)2008 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
2009 u32 *type_size)
2010 {
2011 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
2012 }
2013
btf_resolved_type_id(const struct btf * btf,u32 type_id)2014 static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
2015 {
2016 while (type_id < btf->start_id)
2017 btf = btf->base_btf;
2018
2019 return btf->resolved_ids[type_id - btf->start_id];
2020 }
2021
2022 /* The input param "type_id" must point to a needs_resolve type */
btf_type_id_resolve(const struct btf * btf,u32 * type_id)2023 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
2024 u32 *type_id)
2025 {
2026 *type_id = btf_resolved_type_id(btf, *type_id);
2027 return btf_type_by_id(btf, *type_id);
2028 }
2029
btf_resolved_type_size(const struct btf * btf,u32 type_id)2030 static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
2031 {
2032 while (type_id < btf->start_id)
2033 btf = btf->base_btf;
2034
2035 return btf->resolved_sizes[type_id - btf->start_id];
2036 }
2037
btf_type_id_size(const struct btf * btf,u32 * type_id,u32 * ret_size)2038 const struct btf_type *btf_type_id_size(const struct btf *btf,
2039 u32 *type_id, u32 *ret_size)
2040 {
2041 const struct btf_type *size_type;
2042 u32 size_type_id = *type_id;
2043 u32 size = 0;
2044
2045 size_type = btf_type_by_id(btf, size_type_id);
2046 if (btf_type_nosize_or_null(size_type))
2047 return NULL;
2048
2049 if (btf_type_has_size(size_type)) {
2050 size = size_type->size;
2051 } else if (btf_type_is_array(size_type)) {
2052 size = btf_resolved_type_size(btf, size_type_id);
2053 } else if (btf_type_is_ptr(size_type)) {
2054 size = sizeof(void *);
2055 } else {
2056 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
2057 !btf_type_is_var(size_type)))
2058 return NULL;
2059
2060 size_type_id = btf_resolved_type_id(btf, size_type_id);
2061 size_type = btf_type_by_id(btf, size_type_id);
2062 if (btf_type_nosize_or_null(size_type))
2063 return NULL;
2064 else if (btf_type_has_size(size_type))
2065 size = size_type->size;
2066 else if (btf_type_is_array(size_type))
2067 size = btf_resolved_type_size(btf, size_type_id);
2068 else if (btf_type_is_ptr(size_type))
2069 size = sizeof(void *);
2070 else
2071 return NULL;
2072 }
2073
2074 *type_id = size_type_id;
2075 if (ret_size)
2076 *ret_size = size;
2077
2078 return size_type;
2079 }
2080
btf_df_check_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2081 static int btf_df_check_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 btf_verifier_log_basic(env, struct_type,
2087 "Unsupported check_member");
2088 return -EINVAL;
2089 }
2090
btf_df_check_kflag_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2091 static int btf_df_check_kflag_member(struct btf_verifier_env *env,
2092 const struct btf_type *struct_type,
2093 const struct btf_member *member,
2094 const struct btf_type *member_type)
2095 {
2096 btf_verifier_log_basic(env, struct_type,
2097 "Unsupported check_kflag_member");
2098 return -EINVAL;
2099 }
2100
2101 /* Used for ptr, array struct/union and float type members.
2102 * int, enum and modifier types have their specific callback functions.
2103 */
btf_generic_check_kflag_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2104 static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
2105 const struct btf_type *struct_type,
2106 const struct btf_member *member,
2107 const struct btf_type *member_type)
2108 {
2109 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2110 btf_verifier_log_member(env, struct_type, member,
2111 "Invalid member bitfield_size");
2112 return -EINVAL;
2113 }
2114
2115 /* bitfield size is 0, so member->offset represents bit offset only.
2116 * It is safe to call non kflag check_member variants.
2117 */
2118 return btf_type_ops(member_type)->check_member(env, struct_type,
2119 member,
2120 member_type);
2121 }
2122
btf_df_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)2123 static int btf_df_resolve(struct btf_verifier_env *env,
2124 const struct resolve_vertex *v)
2125 {
2126 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2127 return -EINVAL;
2128 }
2129
btf_df_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offsets,struct btf_show * show)2130 static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2131 u32 type_id, void *data, u8 bits_offsets,
2132 struct btf_show *show)
2133 {
2134 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2135 }
2136
btf_int_check_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2137 static int btf_int_check_member(struct btf_verifier_env *env,
2138 const struct btf_type *struct_type,
2139 const struct btf_member *member,
2140 const struct btf_type *member_type)
2141 {
2142 u32 int_data = btf_type_int(member_type);
2143 u32 struct_bits_off = member->offset;
2144 u32 struct_size = struct_type->size;
2145 u32 nr_copy_bits;
2146 u32 bytes_offset;
2147
2148 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2149 btf_verifier_log_member(env, struct_type, member,
2150 "bits_offset exceeds U32_MAX");
2151 return -EINVAL;
2152 }
2153
2154 struct_bits_off += BTF_INT_OFFSET(int_data);
2155 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2156 nr_copy_bits = BTF_INT_BITS(int_data) +
2157 BITS_PER_BYTE_MASKED(struct_bits_off);
2158
2159 if (nr_copy_bits > BITS_PER_U128) {
2160 btf_verifier_log_member(env, struct_type, member,
2161 "nr_copy_bits exceeds 128");
2162 return -EINVAL;
2163 }
2164
2165 if (struct_size < bytes_offset ||
2166 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2167 btf_verifier_log_member(env, struct_type, member,
2168 "Member exceeds struct_size");
2169 return -EINVAL;
2170 }
2171
2172 return 0;
2173 }
2174
btf_int_check_kflag_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2175 static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2176 const struct btf_type *struct_type,
2177 const struct btf_member *member,
2178 const struct btf_type *member_type)
2179 {
2180 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2181 u32 int_data = btf_type_int(member_type);
2182 u32 struct_size = struct_type->size;
2183 u32 nr_copy_bits;
2184
2185 /* a regular int type is required for the kflag int member */
2186 if (!btf_type_int_is_regular(member_type)) {
2187 btf_verifier_log_member(env, struct_type, member,
2188 "Invalid member base type");
2189 return -EINVAL;
2190 }
2191
2192 /* check sanity of bitfield size */
2193 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2194 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2195 nr_int_data_bits = BTF_INT_BITS(int_data);
2196 if (!nr_bits) {
2197 /* Not a bitfield member, member offset must be at byte
2198 * boundary.
2199 */
2200 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2201 btf_verifier_log_member(env, struct_type, member,
2202 "Invalid member offset");
2203 return -EINVAL;
2204 }
2205
2206 nr_bits = nr_int_data_bits;
2207 } else if (nr_bits > nr_int_data_bits) {
2208 btf_verifier_log_member(env, struct_type, member,
2209 "Invalid member bitfield_size");
2210 return -EINVAL;
2211 }
2212
2213 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2214 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2215 if (nr_copy_bits > BITS_PER_U128) {
2216 btf_verifier_log_member(env, struct_type, member,
2217 "nr_copy_bits exceeds 128");
2218 return -EINVAL;
2219 }
2220
2221 if (struct_size < bytes_offset ||
2222 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2223 btf_verifier_log_member(env, struct_type, member,
2224 "Member exceeds struct_size");
2225 return -EINVAL;
2226 }
2227
2228 return 0;
2229 }
2230
btf_int_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)2231 static s32 btf_int_check_meta(struct btf_verifier_env *env,
2232 const struct btf_type *t,
2233 u32 meta_left)
2234 {
2235 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2236 u16 encoding;
2237
2238 if (meta_left < meta_needed) {
2239 btf_verifier_log_basic(env, t,
2240 "meta_left:%u meta_needed:%u",
2241 meta_left, meta_needed);
2242 return -EINVAL;
2243 }
2244
2245 if (btf_type_vlen(t)) {
2246 btf_verifier_log_type(env, t, "vlen != 0");
2247 return -EINVAL;
2248 }
2249
2250 if (btf_type_kflag(t)) {
2251 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2252 return -EINVAL;
2253 }
2254
2255 int_data = btf_type_int(t);
2256 if (int_data & ~BTF_INT_MASK) {
2257 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2258 int_data);
2259 return -EINVAL;
2260 }
2261
2262 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2263
2264 if (nr_bits > BITS_PER_U128) {
2265 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2266 BITS_PER_U128);
2267 return -EINVAL;
2268 }
2269
2270 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2271 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2272 return -EINVAL;
2273 }
2274
2275 /*
2276 * Only one of the encoding bits is allowed and it
2277 * should be sufficient for the pretty print purpose (i.e. decoding).
2278 * Multiple bits can be allowed later if it is found
2279 * to be insufficient.
2280 */
2281 encoding = BTF_INT_ENCODING(int_data);
2282 if (encoding &&
2283 encoding != BTF_INT_SIGNED &&
2284 encoding != BTF_INT_CHAR &&
2285 encoding != BTF_INT_BOOL) {
2286 btf_verifier_log_type(env, t, "Unsupported encoding");
2287 return -ENOTSUPP;
2288 }
2289
2290 btf_verifier_log_type(env, t, NULL);
2291
2292 return meta_needed;
2293 }
2294
btf_int_log(struct btf_verifier_env * env,const struct btf_type * t)2295 static void btf_int_log(struct btf_verifier_env *env,
2296 const struct btf_type *t)
2297 {
2298 int int_data = btf_type_int(t);
2299
2300 btf_verifier_log(env,
2301 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2302 t->size, BTF_INT_OFFSET(int_data),
2303 BTF_INT_BITS(int_data),
2304 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2305 }
2306
btf_int128_print(struct btf_show * show,void * data)2307 static void btf_int128_print(struct btf_show *show, void *data)
2308 {
2309 /* data points to a __int128 number.
2310 * Suppose
2311 * int128_num = *(__int128 *)data;
2312 * The below formulas shows what upper_num and lower_num represents:
2313 * upper_num = int128_num >> 64;
2314 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2315 */
2316 u64 upper_num, lower_num;
2317
2318 #ifdef __BIG_ENDIAN_BITFIELD
2319 upper_num = *(u64 *)data;
2320 lower_num = *(u64 *)(data + 8);
2321 #else
2322 upper_num = *(u64 *)(data + 8);
2323 lower_num = *(u64 *)data;
2324 #endif
2325 if (upper_num == 0)
2326 btf_show_type_value(show, "0x%llx", lower_num);
2327 else
2328 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2329 lower_num);
2330 }
2331
btf_int128_shift(u64 * print_num,u16 left_shift_bits,u16 right_shift_bits)2332 static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2333 u16 right_shift_bits)
2334 {
2335 u64 upper_num, lower_num;
2336
2337 #ifdef __BIG_ENDIAN_BITFIELD
2338 upper_num = print_num[0];
2339 lower_num = print_num[1];
2340 #else
2341 upper_num = print_num[1];
2342 lower_num = print_num[0];
2343 #endif
2344
2345 /* shake out un-needed bits by shift/or operations */
2346 if (left_shift_bits >= 64) {
2347 upper_num = lower_num << (left_shift_bits - 64);
2348 lower_num = 0;
2349 } else {
2350 upper_num = (upper_num << left_shift_bits) |
2351 (lower_num >> (64 - left_shift_bits));
2352 lower_num = lower_num << left_shift_bits;
2353 }
2354
2355 if (right_shift_bits >= 64) {
2356 lower_num = upper_num >> (right_shift_bits - 64);
2357 upper_num = 0;
2358 } else {
2359 lower_num = (lower_num >> right_shift_bits) |
2360 (upper_num << (64 - right_shift_bits));
2361 upper_num = upper_num >> right_shift_bits;
2362 }
2363
2364 #ifdef __BIG_ENDIAN_BITFIELD
2365 print_num[0] = upper_num;
2366 print_num[1] = lower_num;
2367 #else
2368 print_num[0] = lower_num;
2369 print_num[1] = upper_num;
2370 #endif
2371 }
2372
btf_bitfield_show(void * data,u8 bits_offset,u8 nr_bits,struct btf_show * show)2373 static void btf_bitfield_show(void *data, u8 bits_offset,
2374 u8 nr_bits, struct btf_show *show)
2375 {
2376 u16 left_shift_bits, right_shift_bits;
2377 u8 nr_copy_bytes;
2378 u8 nr_copy_bits;
2379 u64 print_num[2] = {};
2380
2381 nr_copy_bits = nr_bits + bits_offset;
2382 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2383
2384 memcpy(print_num, data, nr_copy_bytes);
2385
2386 #ifdef __BIG_ENDIAN_BITFIELD
2387 left_shift_bits = bits_offset;
2388 #else
2389 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2390 #endif
2391 right_shift_bits = BITS_PER_U128 - nr_bits;
2392
2393 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2394 btf_int128_print(show, print_num);
2395 }
2396
2397
btf_int_bits_show(const struct btf * btf,const struct btf_type * t,void * data,u8 bits_offset,struct btf_show * show)2398 static void btf_int_bits_show(const struct btf *btf,
2399 const struct btf_type *t,
2400 void *data, u8 bits_offset,
2401 struct btf_show *show)
2402 {
2403 u32 int_data = btf_type_int(t);
2404 u8 nr_bits = BTF_INT_BITS(int_data);
2405 u8 total_bits_offset;
2406
2407 /*
2408 * bits_offset is at most 7.
2409 * BTF_INT_OFFSET() cannot exceed 128 bits.
2410 */
2411 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2412 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2413 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2414 btf_bitfield_show(data, bits_offset, nr_bits, show);
2415 }
2416
btf_int_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)2417 static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2418 u32 type_id, void *data, u8 bits_offset,
2419 struct btf_show *show)
2420 {
2421 u32 int_data = btf_type_int(t);
2422 u8 encoding = BTF_INT_ENCODING(int_data);
2423 bool sign = encoding & BTF_INT_SIGNED;
2424 u8 nr_bits = BTF_INT_BITS(int_data);
2425 void *safe_data;
2426
2427 safe_data = btf_show_start_type(show, t, type_id, data);
2428 if (!safe_data)
2429 return;
2430
2431 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2432 BITS_PER_BYTE_MASKED(nr_bits)) {
2433 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2434 goto out;
2435 }
2436
2437 switch (nr_bits) {
2438 case 128:
2439 btf_int128_print(show, safe_data);
2440 break;
2441 case 64:
2442 if (sign)
2443 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2444 else
2445 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2446 break;
2447 case 32:
2448 if (sign)
2449 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2450 else
2451 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2452 break;
2453 case 16:
2454 if (sign)
2455 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2456 else
2457 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2458 break;
2459 case 8:
2460 if (show->state.array_encoding == BTF_INT_CHAR) {
2461 /* check for null terminator */
2462 if (show->state.array_terminated)
2463 break;
2464 if (*(char *)data == '\0') {
2465 show->state.array_terminated = 1;
2466 break;
2467 }
2468 if (isprint(*(char *)data)) {
2469 btf_show_type_value(show, "'%c'",
2470 *(char *)safe_data);
2471 break;
2472 }
2473 }
2474 if (sign)
2475 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2476 else
2477 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2478 break;
2479 default:
2480 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2481 break;
2482 }
2483 out:
2484 btf_show_end_type(show);
2485 }
2486
2487 static const struct btf_kind_operations int_ops = {
2488 .check_meta = btf_int_check_meta,
2489 .resolve = btf_df_resolve,
2490 .check_member = btf_int_check_member,
2491 .check_kflag_member = btf_int_check_kflag_member,
2492 .log_details = btf_int_log,
2493 .show = btf_int_show,
2494 };
2495
btf_modifier_check_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2496 static int btf_modifier_check_member(struct btf_verifier_env *env,
2497 const struct btf_type *struct_type,
2498 const struct btf_member *member,
2499 const struct btf_type *member_type)
2500 {
2501 const struct btf_type *resolved_type;
2502 u32 resolved_type_id = member->type;
2503 struct btf_member resolved_member;
2504 struct btf *btf = env->btf;
2505
2506 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2507 if (!resolved_type) {
2508 btf_verifier_log_member(env, struct_type, member,
2509 "Invalid member");
2510 return -EINVAL;
2511 }
2512
2513 resolved_member = *member;
2514 resolved_member.type = resolved_type_id;
2515
2516 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2517 &resolved_member,
2518 resolved_type);
2519 }
2520
btf_modifier_check_kflag_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2521 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2522 const struct btf_type *struct_type,
2523 const struct btf_member *member,
2524 const struct btf_type *member_type)
2525 {
2526 const struct btf_type *resolved_type;
2527 u32 resolved_type_id = member->type;
2528 struct btf_member resolved_member;
2529 struct btf *btf = env->btf;
2530
2531 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2532 if (!resolved_type) {
2533 btf_verifier_log_member(env, struct_type, member,
2534 "Invalid member");
2535 return -EINVAL;
2536 }
2537
2538 resolved_member = *member;
2539 resolved_member.type = resolved_type_id;
2540
2541 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2542 &resolved_member,
2543 resolved_type);
2544 }
2545
btf_ptr_check_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2546 static int btf_ptr_check_member(struct btf_verifier_env *env,
2547 const struct btf_type *struct_type,
2548 const struct btf_member *member,
2549 const struct btf_type *member_type)
2550 {
2551 u32 struct_size, struct_bits_off, bytes_offset;
2552
2553 struct_size = struct_type->size;
2554 struct_bits_off = member->offset;
2555 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2556
2557 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2558 btf_verifier_log_member(env, struct_type, member,
2559 "Member is not byte aligned");
2560 return -EINVAL;
2561 }
2562
2563 if (struct_size - bytes_offset < sizeof(void *)) {
2564 btf_verifier_log_member(env, struct_type, member,
2565 "Member exceeds struct_size");
2566 return -EINVAL;
2567 }
2568
2569 return 0;
2570 }
2571
btf_ref_type_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)2572 static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2573 const struct btf_type *t,
2574 u32 meta_left)
2575 {
2576 const char *value;
2577
2578 if (btf_type_vlen(t)) {
2579 btf_verifier_log_type(env, t, "vlen != 0");
2580 return -EINVAL;
2581 }
2582
2583 if (btf_type_kflag(t)) {
2584 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2585 return -EINVAL;
2586 }
2587
2588 if (!BTF_TYPE_ID_VALID(t->type)) {
2589 btf_verifier_log_type(env, t, "Invalid type_id");
2590 return -EINVAL;
2591 }
2592
2593 /* typedef/type_tag type must have a valid name, and other ref types,
2594 * volatile, const, restrict, should have a null name.
2595 */
2596 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2597 if (!t->name_off ||
2598 !btf_name_valid_identifier(env->btf, t->name_off)) {
2599 btf_verifier_log_type(env, t, "Invalid name");
2600 return -EINVAL;
2601 }
2602 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2603 value = btf_name_by_offset(env->btf, t->name_off);
2604 if (!value || !value[0]) {
2605 btf_verifier_log_type(env, t, "Invalid name");
2606 return -EINVAL;
2607 }
2608 } else {
2609 if (t->name_off) {
2610 btf_verifier_log_type(env, t, "Invalid name");
2611 return -EINVAL;
2612 }
2613 }
2614
2615 btf_verifier_log_type(env, t, NULL);
2616
2617 return 0;
2618 }
2619
btf_modifier_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)2620 static int btf_modifier_resolve(struct btf_verifier_env *env,
2621 const struct resolve_vertex *v)
2622 {
2623 const struct btf_type *t = v->t;
2624 const struct btf_type *next_type;
2625 u32 next_type_id = t->type;
2626 struct btf *btf = env->btf;
2627
2628 next_type = btf_type_by_id(btf, next_type_id);
2629 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2630 btf_verifier_log_type(env, v->t, "Invalid type_id");
2631 return -EINVAL;
2632 }
2633
2634 if (!env_type_is_resolve_sink(env, next_type) &&
2635 !env_type_is_resolved(env, next_type_id))
2636 return env_stack_push(env, next_type, next_type_id);
2637
2638 /* Figure out the resolved next_type_id with size.
2639 * They will be stored in the current modifier's
2640 * resolved_ids and resolved_sizes such that it can
2641 * save us a few type-following when we use it later (e.g. in
2642 * pretty print).
2643 */
2644 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2645 if (env_type_is_resolved(env, next_type_id))
2646 next_type = btf_type_id_resolve(btf, &next_type_id);
2647
2648 /* "typedef void new_void", "const void"...etc */
2649 if (!btf_type_is_void(next_type) &&
2650 !btf_type_is_fwd(next_type) &&
2651 !btf_type_is_func_proto(next_type)) {
2652 btf_verifier_log_type(env, v->t, "Invalid type_id");
2653 return -EINVAL;
2654 }
2655 }
2656
2657 env_stack_pop_resolved(env, next_type_id, 0);
2658
2659 return 0;
2660 }
2661
btf_var_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)2662 static int btf_var_resolve(struct btf_verifier_env *env,
2663 const struct resolve_vertex *v)
2664 {
2665 const struct btf_type *next_type;
2666 const struct btf_type *t = v->t;
2667 u32 next_type_id = t->type;
2668 struct btf *btf = env->btf;
2669
2670 next_type = btf_type_by_id(btf, next_type_id);
2671 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2672 btf_verifier_log_type(env, v->t, "Invalid type_id");
2673 return -EINVAL;
2674 }
2675
2676 if (!env_type_is_resolve_sink(env, next_type) &&
2677 !env_type_is_resolved(env, next_type_id))
2678 return env_stack_push(env, next_type, next_type_id);
2679
2680 if (btf_type_is_modifier(next_type)) {
2681 const struct btf_type *resolved_type;
2682 u32 resolved_type_id;
2683
2684 resolved_type_id = next_type_id;
2685 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2686
2687 if (btf_type_is_ptr(resolved_type) &&
2688 !env_type_is_resolve_sink(env, resolved_type) &&
2689 !env_type_is_resolved(env, resolved_type_id))
2690 return env_stack_push(env, resolved_type,
2691 resolved_type_id);
2692 }
2693
2694 /* We must resolve to something concrete at this point, no
2695 * forward types or similar that would resolve to size of
2696 * zero is allowed.
2697 */
2698 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2699 btf_verifier_log_type(env, v->t, "Invalid type_id");
2700 return -EINVAL;
2701 }
2702
2703 env_stack_pop_resolved(env, next_type_id, 0);
2704
2705 return 0;
2706 }
2707
btf_ptr_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)2708 static int btf_ptr_resolve(struct btf_verifier_env *env,
2709 const struct resolve_vertex *v)
2710 {
2711 const struct btf_type *next_type;
2712 const struct btf_type *t = v->t;
2713 u32 next_type_id = t->type;
2714 struct btf *btf = env->btf;
2715
2716 next_type = btf_type_by_id(btf, next_type_id);
2717 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2718 btf_verifier_log_type(env, v->t, "Invalid type_id");
2719 return -EINVAL;
2720 }
2721
2722 if (!env_type_is_resolve_sink(env, next_type) &&
2723 !env_type_is_resolved(env, next_type_id))
2724 return env_stack_push(env, next_type, next_type_id);
2725
2726 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2727 * the modifier may have stopped resolving when it was resolved
2728 * to a ptr (last-resolved-ptr).
2729 *
2730 * We now need to continue from the last-resolved-ptr to
2731 * ensure the last-resolved-ptr will not referring back to
2732 * the current ptr (t).
2733 */
2734 if (btf_type_is_modifier(next_type)) {
2735 const struct btf_type *resolved_type;
2736 u32 resolved_type_id;
2737
2738 resolved_type_id = next_type_id;
2739 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2740
2741 if (btf_type_is_ptr(resolved_type) &&
2742 !env_type_is_resolve_sink(env, resolved_type) &&
2743 !env_type_is_resolved(env, resolved_type_id))
2744 return env_stack_push(env, resolved_type,
2745 resolved_type_id);
2746 }
2747
2748 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2749 if (env_type_is_resolved(env, next_type_id))
2750 next_type = btf_type_id_resolve(btf, &next_type_id);
2751
2752 if (!btf_type_is_void(next_type) &&
2753 !btf_type_is_fwd(next_type) &&
2754 !btf_type_is_func_proto(next_type)) {
2755 btf_verifier_log_type(env, v->t, "Invalid type_id");
2756 return -EINVAL;
2757 }
2758 }
2759
2760 env_stack_pop_resolved(env, next_type_id, 0);
2761
2762 return 0;
2763 }
2764
btf_modifier_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)2765 static void btf_modifier_show(const struct btf *btf,
2766 const struct btf_type *t,
2767 u32 type_id, void *data,
2768 u8 bits_offset, struct btf_show *show)
2769 {
2770 if (btf->resolved_ids)
2771 t = btf_type_id_resolve(btf, &type_id);
2772 else
2773 t = btf_type_skip_modifiers(btf, type_id, NULL);
2774
2775 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2776 }
2777
btf_var_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)2778 static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2779 u32 type_id, void *data, u8 bits_offset,
2780 struct btf_show *show)
2781 {
2782 t = btf_type_id_resolve(btf, &type_id);
2783
2784 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2785 }
2786
btf_ptr_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)2787 static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2788 u32 type_id, void *data, u8 bits_offset,
2789 struct btf_show *show)
2790 {
2791 void *safe_data;
2792
2793 safe_data = btf_show_start_type(show, t, type_id, data);
2794 if (!safe_data)
2795 return;
2796
2797 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2798 if (show->flags & BTF_SHOW_PTR_RAW)
2799 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2800 else
2801 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2802 btf_show_end_type(show);
2803 }
2804
btf_ref_type_log(struct btf_verifier_env * env,const struct btf_type * t)2805 static void btf_ref_type_log(struct btf_verifier_env *env,
2806 const struct btf_type *t)
2807 {
2808 btf_verifier_log(env, "type_id=%u", t->type);
2809 }
2810
2811 static struct btf_kind_operations modifier_ops = {
2812 .check_meta = btf_ref_type_check_meta,
2813 .resolve = btf_modifier_resolve,
2814 .check_member = btf_modifier_check_member,
2815 .check_kflag_member = btf_modifier_check_kflag_member,
2816 .log_details = btf_ref_type_log,
2817 .show = btf_modifier_show,
2818 };
2819
2820 static struct btf_kind_operations ptr_ops = {
2821 .check_meta = btf_ref_type_check_meta,
2822 .resolve = btf_ptr_resolve,
2823 .check_member = btf_ptr_check_member,
2824 .check_kflag_member = btf_generic_check_kflag_member,
2825 .log_details = btf_ref_type_log,
2826 .show = btf_ptr_show,
2827 };
2828
btf_fwd_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)2829 static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2830 const struct btf_type *t,
2831 u32 meta_left)
2832 {
2833 if (btf_type_vlen(t)) {
2834 btf_verifier_log_type(env, t, "vlen != 0");
2835 return -EINVAL;
2836 }
2837
2838 if (t->type) {
2839 btf_verifier_log_type(env, t, "type != 0");
2840 return -EINVAL;
2841 }
2842
2843 /* fwd type must have a valid name */
2844 if (!t->name_off ||
2845 !btf_name_valid_identifier(env->btf, t->name_off)) {
2846 btf_verifier_log_type(env, t, "Invalid name");
2847 return -EINVAL;
2848 }
2849
2850 btf_verifier_log_type(env, t, NULL);
2851
2852 return 0;
2853 }
2854
btf_fwd_type_log(struct btf_verifier_env * env,const struct btf_type * t)2855 static void btf_fwd_type_log(struct btf_verifier_env *env,
2856 const struct btf_type *t)
2857 {
2858 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2859 }
2860
2861 static struct btf_kind_operations fwd_ops = {
2862 .check_meta = btf_fwd_check_meta,
2863 .resolve = btf_df_resolve,
2864 .check_member = btf_df_check_member,
2865 .check_kflag_member = btf_df_check_kflag_member,
2866 .log_details = btf_fwd_type_log,
2867 .show = btf_df_show,
2868 };
2869
btf_array_check_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)2870 static int btf_array_check_member(struct btf_verifier_env *env,
2871 const struct btf_type *struct_type,
2872 const struct btf_member *member,
2873 const struct btf_type *member_type)
2874 {
2875 u32 struct_bits_off = member->offset;
2876 u32 struct_size, bytes_offset;
2877 u32 array_type_id, array_size;
2878 struct btf *btf = env->btf;
2879
2880 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2881 btf_verifier_log_member(env, struct_type, member,
2882 "Member is not byte aligned");
2883 return -EINVAL;
2884 }
2885
2886 array_type_id = member->type;
2887 btf_type_id_size(btf, &array_type_id, &array_size);
2888 struct_size = struct_type->size;
2889 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2890 if (struct_size - bytes_offset < array_size) {
2891 btf_verifier_log_member(env, struct_type, member,
2892 "Member exceeds struct_size");
2893 return -EINVAL;
2894 }
2895
2896 return 0;
2897 }
2898
btf_array_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)2899 static s32 btf_array_check_meta(struct btf_verifier_env *env,
2900 const struct btf_type *t,
2901 u32 meta_left)
2902 {
2903 const struct btf_array *array = btf_type_array(t);
2904 u32 meta_needed = sizeof(*array);
2905
2906 if (meta_left < meta_needed) {
2907 btf_verifier_log_basic(env, t,
2908 "meta_left:%u meta_needed:%u",
2909 meta_left, meta_needed);
2910 return -EINVAL;
2911 }
2912
2913 /* array type should not have a name */
2914 if (t->name_off) {
2915 btf_verifier_log_type(env, t, "Invalid name");
2916 return -EINVAL;
2917 }
2918
2919 if (btf_type_vlen(t)) {
2920 btf_verifier_log_type(env, t, "vlen != 0");
2921 return -EINVAL;
2922 }
2923
2924 if (btf_type_kflag(t)) {
2925 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2926 return -EINVAL;
2927 }
2928
2929 if (t->size) {
2930 btf_verifier_log_type(env, t, "size != 0");
2931 return -EINVAL;
2932 }
2933
2934 /* Array elem type and index type cannot be in type void,
2935 * so !array->type and !array->index_type are not allowed.
2936 */
2937 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2938 btf_verifier_log_type(env, t, "Invalid elem");
2939 return -EINVAL;
2940 }
2941
2942 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2943 btf_verifier_log_type(env, t, "Invalid index");
2944 return -EINVAL;
2945 }
2946
2947 btf_verifier_log_type(env, t, NULL);
2948
2949 return meta_needed;
2950 }
2951
btf_array_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)2952 static int btf_array_resolve(struct btf_verifier_env *env,
2953 const struct resolve_vertex *v)
2954 {
2955 const struct btf_array *array = btf_type_array(v->t);
2956 const struct btf_type *elem_type, *index_type;
2957 u32 elem_type_id, index_type_id;
2958 struct btf *btf = env->btf;
2959 u32 elem_size;
2960
2961 /* Check array->index_type */
2962 index_type_id = array->index_type;
2963 index_type = btf_type_by_id(btf, index_type_id);
2964 if (btf_type_nosize_or_null(index_type) ||
2965 btf_type_is_resolve_source_only(index_type)) {
2966 btf_verifier_log_type(env, v->t, "Invalid index");
2967 return -EINVAL;
2968 }
2969
2970 if (!env_type_is_resolve_sink(env, index_type) &&
2971 !env_type_is_resolved(env, index_type_id))
2972 return env_stack_push(env, index_type, index_type_id);
2973
2974 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2975 if (!index_type || !btf_type_is_int(index_type) ||
2976 !btf_type_int_is_regular(index_type)) {
2977 btf_verifier_log_type(env, v->t, "Invalid index");
2978 return -EINVAL;
2979 }
2980
2981 /* Check array->type */
2982 elem_type_id = array->type;
2983 elem_type = btf_type_by_id(btf, elem_type_id);
2984 if (btf_type_nosize_or_null(elem_type) ||
2985 btf_type_is_resolve_source_only(elem_type)) {
2986 btf_verifier_log_type(env, v->t,
2987 "Invalid elem");
2988 return -EINVAL;
2989 }
2990
2991 if (!env_type_is_resolve_sink(env, elem_type) &&
2992 !env_type_is_resolved(env, elem_type_id))
2993 return env_stack_push(env, elem_type, elem_type_id);
2994
2995 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2996 if (!elem_type) {
2997 btf_verifier_log_type(env, v->t, "Invalid elem");
2998 return -EINVAL;
2999 }
3000
3001 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
3002 btf_verifier_log_type(env, v->t, "Invalid array of int");
3003 return -EINVAL;
3004 }
3005
3006 if (array->nelems && elem_size > U32_MAX / array->nelems) {
3007 btf_verifier_log_type(env, v->t,
3008 "Array size overflows U32_MAX");
3009 return -EINVAL;
3010 }
3011
3012 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
3013
3014 return 0;
3015 }
3016
btf_array_log(struct btf_verifier_env * env,const struct btf_type * t)3017 static void btf_array_log(struct btf_verifier_env *env,
3018 const struct btf_type *t)
3019 {
3020 const struct btf_array *array = btf_type_array(t);
3021
3022 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
3023 array->type, array->index_type, array->nelems);
3024 }
3025
__btf_array_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)3026 static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
3027 u32 type_id, void *data, u8 bits_offset,
3028 struct btf_show *show)
3029 {
3030 const struct btf_array *array = btf_type_array(t);
3031 const struct btf_kind_operations *elem_ops;
3032 const struct btf_type *elem_type;
3033 u32 i, elem_size = 0, elem_type_id;
3034 u16 encoding = 0;
3035
3036 elem_type_id = array->type;
3037 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
3038 if (elem_type && btf_type_has_size(elem_type))
3039 elem_size = elem_type->size;
3040
3041 if (elem_type && btf_type_is_int(elem_type)) {
3042 u32 int_type = btf_type_int(elem_type);
3043
3044 encoding = BTF_INT_ENCODING(int_type);
3045
3046 /*
3047 * BTF_INT_CHAR encoding never seems to be set for
3048 * char arrays, so if size is 1 and element is
3049 * printable as a char, we'll do that.
3050 */
3051 if (elem_size == 1)
3052 encoding = BTF_INT_CHAR;
3053 }
3054
3055 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
3056 return;
3057
3058 if (!elem_type)
3059 goto out;
3060 elem_ops = btf_type_ops(elem_type);
3061
3062 for (i = 0; i < array->nelems; i++) {
3063
3064 btf_show_start_array_member(show);
3065
3066 elem_ops->show(btf, elem_type, elem_type_id, data,
3067 bits_offset, show);
3068 data += elem_size;
3069
3070 btf_show_end_array_member(show);
3071
3072 if (show->state.array_terminated)
3073 break;
3074 }
3075 out:
3076 btf_show_end_array_type(show);
3077 }
3078
btf_array_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)3079 static void btf_array_show(const struct btf *btf, const struct btf_type *t,
3080 u32 type_id, void *data, u8 bits_offset,
3081 struct btf_show *show)
3082 {
3083 const struct btf_member *m = show->state.member;
3084
3085 /*
3086 * First check if any members would be shown (are non-zero).
3087 * See comments above "struct btf_show" definition for more
3088 * details on how this works at a high-level.
3089 */
3090 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3091 if (!show->state.depth_check) {
3092 show->state.depth_check = show->state.depth + 1;
3093 show->state.depth_to_show = 0;
3094 }
3095 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3096 show->state.member = m;
3097
3098 if (show->state.depth_check != show->state.depth + 1)
3099 return;
3100 show->state.depth_check = 0;
3101
3102 if (show->state.depth_to_show <= show->state.depth)
3103 return;
3104 /*
3105 * Reaching here indicates we have recursed and found
3106 * non-zero array member(s).
3107 */
3108 }
3109 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3110 }
3111
3112 static struct btf_kind_operations array_ops = {
3113 .check_meta = btf_array_check_meta,
3114 .resolve = btf_array_resolve,
3115 .check_member = btf_array_check_member,
3116 .check_kflag_member = btf_generic_check_kflag_member,
3117 .log_details = btf_array_log,
3118 .show = btf_array_show,
3119 };
3120
btf_struct_check_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)3121 static int btf_struct_check_member(struct btf_verifier_env *env,
3122 const struct btf_type *struct_type,
3123 const struct btf_member *member,
3124 const struct btf_type *member_type)
3125 {
3126 u32 struct_bits_off = member->offset;
3127 u32 struct_size, bytes_offset;
3128
3129 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3130 btf_verifier_log_member(env, struct_type, member,
3131 "Member is not byte aligned");
3132 return -EINVAL;
3133 }
3134
3135 struct_size = struct_type->size;
3136 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3137 if (struct_size - bytes_offset < member_type->size) {
3138 btf_verifier_log_member(env, struct_type, member,
3139 "Member exceeds struct_size");
3140 return -EINVAL;
3141 }
3142
3143 return 0;
3144 }
3145
btf_struct_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)3146 static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3147 const struct btf_type *t,
3148 u32 meta_left)
3149 {
3150 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3151 const struct btf_member *member;
3152 u32 meta_needed, last_offset;
3153 struct btf *btf = env->btf;
3154 u32 struct_size = t->size;
3155 u32 offset;
3156 u16 i;
3157
3158 meta_needed = btf_type_vlen(t) * sizeof(*member);
3159 if (meta_left < meta_needed) {
3160 btf_verifier_log_basic(env, t,
3161 "meta_left:%u meta_needed:%u",
3162 meta_left, meta_needed);
3163 return -EINVAL;
3164 }
3165
3166 /* struct type either no name or a valid one */
3167 if (t->name_off &&
3168 !btf_name_valid_identifier(env->btf, t->name_off)) {
3169 btf_verifier_log_type(env, t, "Invalid name");
3170 return -EINVAL;
3171 }
3172
3173 btf_verifier_log_type(env, t, NULL);
3174
3175 last_offset = 0;
3176 for_each_member(i, t, member) {
3177 if (!btf_name_offset_valid(btf, member->name_off)) {
3178 btf_verifier_log_member(env, t, member,
3179 "Invalid member name_offset:%u",
3180 member->name_off);
3181 return -EINVAL;
3182 }
3183
3184 /* struct member either no name or a valid one */
3185 if (member->name_off &&
3186 !btf_name_valid_identifier(btf, member->name_off)) {
3187 btf_verifier_log_member(env, t, member, "Invalid name");
3188 return -EINVAL;
3189 }
3190 /* A member cannot be in type void */
3191 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3192 btf_verifier_log_member(env, t, member,
3193 "Invalid type_id");
3194 return -EINVAL;
3195 }
3196
3197 offset = __btf_member_bit_offset(t, member);
3198 if (is_union && offset) {
3199 btf_verifier_log_member(env, t, member,
3200 "Invalid member bits_offset");
3201 return -EINVAL;
3202 }
3203
3204 /*
3205 * ">" instead of ">=" because the last member could be
3206 * "char a[0];"
3207 */
3208 if (last_offset > offset) {
3209 btf_verifier_log_member(env, t, member,
3210 "Invalid member bits_offset");
3211 return -EINVAL;
3212 }
3213
3214 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3215 btf_verifier_log_member(env, t, member,
3216 "Member bits_offset exceeds its struct size");
3217 return -EINVAL;
3218 }
3219
3220 btf_verifier_log_member(env, t, member, NULL);
3221 last_offset = offset;
3222 }
3223
3224 return meta_needed;
3225 }
3226
btf_struct_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)3227 static int btf_struct_resolve(struct btf_verifier_env *env,
3228 const struct resolve_vertex *v)
3229 {
3230 const struct btf_member *member;
3231 int err;
3232 u16 i;
3233
3234 /* Before continue resolving the next_member,
3235 * ensure the last member is indeed resolved to a
3236 * type with size info.
3237 */
3238 if (v->next_member) {
3239 const struct btf_type *last_member_type;
3240 const struct btf_member *last_member;
3241 u32 last_member_type_id;
3242
3243 last_member = btf_type_member(v->t) + v->next_member - 1;
3244 last_member_type_id = last_member->type;
3245 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3246 last_member_type_id)))
3247 return -EINVAL;
3248
3249 last_member_type = btf_type_by_id(env->btf,
3250 last_member_type_id);
3251 if (btf_type_kflag(v->t))
3252 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3253 last_member,
3254 last_member_type);
3255 else
3256 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3257 last_member,
3258 last_member_type);
3259 if (err)
3260 return err;
3261 }
3262
3263 for_each_member_from(i, v->next_member, v->t, member) {
3264 u32 member_type_id = member->type;
3265 const struct btf_type *member_type = btf_type_by_id(env->btf,
3266 member_type_id);
3267
3268 if (btf_type_nosize_or_null(member_type) ||
3269 btf_type_is_resolve_source_only(member_type)) {
3270 btf_verifier_log_member(env, v->t, member,
3271 "Invalid member");
3272 return -EINVAL;
3273 }
3274
3275 if (!env_type_is_resolve_sink(env, member_type) &&
3276 !env_type_is_resolved(env, member_type_id)) {
3277 env_stack_set_next_member(env, i + 1);
3278 return env_stack_push(env, member_type, member_type_id);
3279 }
3280
3281 if (btf_type_kflag(v->t))
3282 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3283 member,
3284 member_type);
3285 else
3286 err = btf_type_ops(member_type)->check_member(env, v->t,
3287 member,
3288 member_type);
3289 if (err)
3290 return err;
3291 }
3292
3293 env_stack_pop_resolved(env, 0, 0);
3294
3295 return 0;
3296 }
3297
btf_struct_log(struct btf_verifier_env * env,const struct btf_type * t)3298 static void btf_struct_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
3304 enum {
3305 BTF_FIELD_IGNORE = 0,
3306 BTF_FIELD_FOUND = 1,
3307 };
3308
3309 struct btf_field_info {
3310 enum btf_field_type type;
3311 u32 off;
3312 union {
3313 struct {
3314 u32 type_id;
3315 } kptr;
3316 struct {
3317 const char *node_name;
3318 u32 value_btf_id;
3319 } graph_root;
3320 };
3321 };
3322
btf_find_struct(const struct btf * btf,const struct btf_type * t,u32 off,int sz,enum btf_field_type field_type,struct btf_field_info * info)3323 static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3324 u32 off, int sz, enum btf_field_type field_type,
3325 struct btf_field_info *info)
3326 {
3327 if (!__btf_type_is_struct(t))
3328 return BTF_FIELD_IGNORE;
3329 if (t->size != sz)
3330 return BTF_FIELD_IGNORE;
3331 info->type = field_type;
3332 info->off = off;
3333 return BTF_FIELD_FOUND;
3334 }
3335
btf_find_kptr(const struct btf * btf,const struct btf_type * t,u32 off,int sz,struct btf_field_info * info)3336 static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3337 u32 off, int sz, struct btf_field_info *info)
3338 {
3339 enum btf_field_type type;
3340 u32 res_id;
3341
3342 /* Permit modifiers on the pointer itself */
3343 if (btf_type_is_volatile(t))
3344 t = btf_type_by_id(btf, t->type);
3345 /* For PTR, sz is always == 8 */
3346 if (!btf_type_is_ptr(t))
3347 return BTF_FIELD_IGNORE;
3348 t = btf_type_by_id(btf, t->type);
3349
3350 if (!btf_type_is_type_tag(t))
3351 return BTF_FIELD_IGNORE;
3352 /* Reject extra tags */
3353 if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3354 return -EINVAL;
3355 if (!strcmp("kptr_untrusted", __btf_name_by_offset(btf, t->name_off)))
3356 type = BPF_KPTR_UNREF;
3357 else if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3358 type = BPF_KPTR_REF;
3359 else if (!strcmp("percpu_kptr", __btf_name_by_offset(btf, t->name_off)))
3360 type = BPF_KPTR_PERCPU;
3361 else
3362 return -EINVAL;
3363
3364 /* Get the base type */
3365 t = btf_type_skip_modifiers(btf, t->type, &res_id);
3366 /* Only pointer to struct is allowed */
3367 if (!__btf_type_is_struct(t))
3368 return -EINVAL;
3369
3370 info->type = type;
3371 info->off = off;
3372 info->kptr.type_id = res_id;
3373 return BTF_FIELD_FOUND;
3374 }
3375
btf_find_next_decl_tag(const struct btf * btf,const struct btf_type * pt,int comp_idx,const char * tag_key,int last_id)3376 int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt,
3377 int comp_idx, const char *tag_key, int last_id)
3378 {
3379 int len = strlen(tag_key);
3380 int i, n;
3381
3382 for (i = last_id + 1, n = btf_nr_types(btf); i < n; i++) {
3383 const struct btf_type *t = btf_type_by_id(btf, i);
3384
3385 if (!btf_type_is_decl_tag(t))
3386 continue;
3387 if (pt != btf_type_by_id(btf, t->type))
3388 continue;
3389 if (btf_type_decl_tag(t)->component_idx != comp_idx)
3390 continue;
3391 if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
3392 continue;
3393 return i;
3394 }
3395 return -ENOENT;
3396 }
3397
btf_find_decl_tag_value(const struct btf * btf,const struct btf_type * pt,int comp_idx,const char * tag_key)3398 const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
3399 int comp_idx, const char *tag_key)
3400 {
3401 const char *value = NULL;
3402 const struct btf_type *t;
3403 int len, id;
3404
3405 id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, 0);
3406 if (id < 0)
3407 return ERR_PTR(id);
3408
3409 t = btf_type_by_id(btf, id);
3410 len = strlen(tag_key);
3411 value = __btf_name_by_offset(btf, t->name_off) + len;
3412
3413 /* Prevent duplicate entries for same type */
3414 id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, id);
3415 if (id >= 0)
3416 return ERR_PTR(-EEXIST);
3417
3418 return value;
3419 }
3420
3421 static int
btf_find_graph_root(const struct btf * btf,const struct btf_type * pt,const struct btf_type * t,int comp_idx,u32 off,int sz,struct btf_field_info * info,enum btf_field_type head_type)3422 btf_find_graph_root(const struct btf *btf, const struct btf_type *pt,
3423 const struct btf_type *t, int comp_idx, u32 off,
3424 int sz, struct btf_field_info *info,
3425 enum btf_field_type head_type)
3426 {
3427 const char *node_field_name;
3428 const char *value_type;
3429 s32 id;
3430
3431 if (!__btf_type_is_struct(t))
3432 return BTF_FIELD_IGNORE;
3433 if (t->size != sz)
3434 return BTF_FIELD_IGNORE;
3435 value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
3436 if (IS_ERR(value_type))
3437 return -EINVAL;
3438 node_field_name = strstr(value_type, ":");
3439 if (!node_field_name)
3440 return -EINVAL;
3441 value_type = kstrndup(value_type, node_field_name - value_type, GFP_KERNEL | __GFP_NOWARN);
3442 if (!value_type)
3443 return -ENOMEM;
3444 id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
3445 kfree(value_type);
3446 if (id < 0)
3447 return id;
3448 node_field_name++;
3449 if (str_is_empty(node_field_name))
3450 return -EINVAL;
3451 info->type = head_type;
3452 info->off = off;
3453 info->graph_root.value_btf_id = id;
3454 info->graph_root.node_name = node_field_name;
3455 return BTF_FIELD_FOUND;
3456 }
3457
3458 #define field_mask_test_name(field_type, field_type_str) \
3459 if (field_mask & field_type && !strcmp(name, field_type_str)) { \
3460 type = field_type; \
3461 goto end; \
3462 }
3463
btf_get_field_type(const struct btf * btf,const struct btf_type * var_type,u32 field_mask,u32 * seen_mask,int * align,int * sz)3464 static int btf_get_field_type(const struct btf *btf, const struct btf_type *var_type,
3465 u32 field_mask, u32 *seen_mask,
3466 int *align, int *sz)
3467 {
3468 int type = 0;
3469 const char *name = __btf_name_by_offset(btf, var_type->name_off);
3470
3471 if (field_mask & BPF_SPIN_LOCK) {
3472 if (!strcmp(name, "bpf_spin_lock")) {
3473 if (*seen_mask & BPF_SPIN_LOCK)
3474 return -E2BIG;
3475 *seen_mask |= BPF_SPIN_LOCK;
3476 type = BPF_SPIN_LOCK;
3477 goto end;
3478 }
3479 }
3480 if (field_mask & BPF_TIMER) {
3481 if (!strcmp(name, "bpf_timer")) {
3482 if (*seen_mask & BPF_TIMER)
3483 return -E2BIG;
3484 *seen_mask |= BPF_TIMER;
3485 type = BPF_TIMER;
3486 goto end;
3487 }
3488 }
3489 if (field_mask & BPF_WORKQUEUE) {
3490 if (!strcmp(name, "bpf_wq")) {
3491 if (*seen_mask & BPF_WORKQUEUE)
3492 return -E2BIG;
3493 *seen_mask |= BPF_WORKQUEUE;
3494 type = BPF_WORKQUEUE;
3495 goto end;
3496 }
3497 }
3498 field_mask_test_name(BPF_LIST_HEAD, "bpf_list_head");
3499 field_mask_test_name(BPF_LIST_NODE, "bpf_list_node");
3500 field_mask_test_name(BPF_RB_ROOT, "bpf_rb_root");
3501 field_mask_test_name(BPF_RB_NODE, "bpf_rb_node");
3502 field_mask_test_name(BPF_REFCOUNT, "bpf_refcount");
3503
3504 /* Only return BPF_KPTR when all other types with matchable names fail */
3505 if (field_mask & BPF_KPTR && !__btf_type_is_struct(var_type)) {
3506 type = BPF_KPTR_REF;
3507 goto end;
3508 }
3509 return 0;
3510 end:
3511 *sz = btf_field_type_size(type);
3512 *align = btf_field_type_align(type);
3513 return type;
3514 }
3515
3516 #undef field_mask_test_name
3517
3518 /* Repeat a number of fields for a specified number of times.
3519 *
3520 * Copy the fields starting from the first field and repeat them for
3521 * repeat_cnt times. The fields are repeated by adding the offset of each
3522 * field with
3523 * (i + 1) * elem_size
3524 * where i is the repeat index and elem_size is the size of an element.
3525 */
btf_repeat_fields(struct btf_field_info * info,u32 field_cnt,u32 repeat_cnt,u32 elem_size)3526 static int btf_repeat_fields(struct btf_field_info *info,
3527 u32 field_cnt, u32 repeat_cnt, u32 elem_size)
3528 {
3529 u32 i, j;
3530 u32 cur;
3531
3532 /* Ensure not repeating fields that should not be repeated. */
3533 for (i = 0; i < field_cnt; i++) {
3534 switch (info[i].type) {
3535 case BPF_KPTR_UNREF:
3536 case BPF_KPTR_REF:
3537 case BPF_KPTR_PERCPU:
3538 case BPF_LIST_HEAD:
3539 case BPF_RB_ROOT:
3540 break;
3541 default:
3542 return -EINVAL;
3543 }
3544 }
3545
3546 cur = field_cnt;
3547 for (i = 0; i < repeat_cnt; i++) {
3548 memcpy(&info[cur], &info[0], field_cnt * sizeof(info[0]));
3549 for (j = 0; j < field_cnt; j++)
3550 info[cur++].off += (i + 1) * elem_size;
3551 }
3552
3553 return 0;
3554 }
3555
3556 static int btf_find_struct_field(const struct btf *btf,
3557 const struct btf_type *t, u32 field_mask,
3558 struct btf_field_info *info, int info_cnt,
3559 u32 level);
3560
3561 /* Find special fields in the struct type of a field.
3562 *
3563 * This function is used to find fields of special types that is not a
3564 * global variable or a direct field of a struct type. It also handles the
3565 * repetition if it is the element type of an array.
3566 */
btf_find_nested_struct(const struct btf * btf,const struct btf_type * t,u32 off,u32 nelems,u32 field_mask,struct btf_field_info * info,int info_cnt,u32 level)3567 static int btf_find_nested_struct(const struct btf *btf, const struct btf_type *t,
3568 u32 off, u32 nelems,
3569 u32 field_mask, struct btf_field_info *info,
3570 int info_cnt, u32 level)
3571 {
3572 int ret, err, i;
3573
3574 level++;
3575 if (level >= MAX_RESOLVE_DEPTH)
3576 return -E2BIG;
3577
3578 ret = btf_find_struct_field(btf, t, field_mask, info, info_cnt, level);
3579
3580 if (ret <= 0)
3581 return ret;
3582
3583 /* Shift the offsets of the nested struct fields to the offsets
3584 * related to the container.
3585 */
3586 for (i = 0; i < ret; i++)
3587 info[i].off += off;
3588
3589 if (nelems > 1) {
3590 err = btf_repeat_fields(info, ret, nelems - 1, t->size);
3591 if (err == 0)
3592 ret *= nelems;
3593 else
3594 ret = err;
3595 }
3596
3597 return ret;
3598 }
3599
btf_find_field_one(const struct btf * btf,const struct btf_type * var,const struct btf_type * var_type,int var_idx,u32 off,u32 expected_size,u32 field_mask,u32 * seen_mask,struct btf_field_info * info,int info_cnt,u32 level)3600 static int btf_find_field_one(const struct btf *btf,
3601 const struct btf_type *var,
3602 const struct btf_type *var_type,
3603 int var_idx,
3604 u32 off, u32 expected_size,
3605 u32 field_mask, u32 *seen_mask,
3606 struct btf_field_info *info, int info_cnt,
3607 u32 level)
3608 {
3609 int ret, align, sz, field_type;
3610 struct btf_field_info tmp;
3611 const struct btf_array *array;
3612 u32 i, nelems = 1;
3613
3614 /* Walk into array types to find the element type and the number of
3615 * elements in the (flattened) array.
3616 */
3617 for (i = 0; i < MAX_RESOLVE_DEPTH && btf_type_is_array(var_type); i++) {
3618 array = btf_array(var_type);
3619 nelems *= array->nelems;
3620 var_type = btf_type_by_id(btf, array->type);
3621 }
3622 if (i == MAX_RESOLVE_DEPTH)
3623 return -E2BIG;
3624 if (nelems == 0)
3625 return 0;
3626
3627 field_type = btf_get_field_type(btf, var_type,
3628 field_mask, seen_mask, &align, &sz);
3629 /* Look into variables of struct types */
3630 if (!field_type && __btf_type_is_struct(var_type)) {
3631 sz = var_type->size;
3632 if (expected_size && expected_size != sz * nelems)
3633 return 0;
3634 ret = btf_find_nested_struct(btf, var_type, off, nelems, field_mask,
3635 &info[0], info_cnt, level);
3636 return ret;
3637 }
3638
3639 if (field_type == 0)
3640 return 0;
3641 if (field_type < 0)
3642 return field_type;
3643
3644 if (expected_size && expected_size != sz * nelems)
3645 return 0;
3646 if (off % align)
3647 return 0;
3648
3649 switch (field_type) {
3650 case BPF_SPIN_LOCK:
3651 case BPF_TIMER:
3652 case BPF_WORKQUEUE:
3653 case BPF_LIST_NODE:
3654 case BPF_RB_NODE:
3655 case BPF_REFCOUNT:
3656 ret = btf_find_struct(btf, var_type, off, sz, field_type,
3657 info_cnt ? &info[0] : &tmp);
3658 if (ret < 0)
3659 return ret;
3660 break;
3661 case BPF_KPTR_UNREF:
3662 case BPF_KPTR_REF:
3663 case BPF_KPTR_PERCPU:
3664 ret = btf_find_kptr(btf, var_type, off, sz,
3665 info_cnt ? &info[0] : &tmp);
3666 if (ret < 0)
3667 return ret;
3668 break;
3669 case BPF_LIST_HEAD:
3670 case BPF_RB_ROOT:
3671 ret = btf_find_graph_root(btf, var, var_type,
3672 var_idx, off, sz,
3673 info_cnt ? &info[0] : &tmp,
3674 field_type);
3675 if (ret < 0)
3676 return ret;
3677 break;
3678 default:
3679 return -EFAULT;
3680 }
3681
3682 if (ret == BTF_FIELD_IGNORE)
3683 return 0;
3684 if (nelems > info_cnt)
3685 return -E2BIG;
3686 if (nelems > 1) {
3687 ret = btf_repeat_fields(info, 1, nelems - 1, sz);
3688 if (ret < 0)
3689 return ret;
3690 }
3691 return nelems;
3692 }
3693
btf_find_struct_field(const struct btf * btf,const struct btf_type * t,u32 field_mask,struct btf_field_info * info,int info_cnt,u32 level)3694 static int btf_find_struct_field(const struct btf *btf,
3695 const struct btf_type *t, u32 field_mask,
3696 struct btf_field_info *info, int info_cnt,
3697 u32 level)
3698 {
3699 int ret, idx = 0;
3700 const struct btf_member *member;
3701 u32 i, off, seen_mask = 0;
3702
3703 for_each_member(i, t, member) {
3704 const struct btf_type *member_type = btf_type_by_id(btf,
3705 member->type);
3706
3707 off = __btf_member_bit_offset(t, member);
3708 if (off % 8)
3709 /* valid C code cannot generate such BTF */
3710 return -EINVAL;
3711 off /= 8;
3712
3713 ret = btf_find_field_one(btf, t, member_type, i,
3714 off, 0,
3715 field_mask, &seen_mask,
3716 &info[idx], info_cnt - idx, level);
3717 if (ret < 0)
3718 return ret;
3719 idx += ret;
3720 }
3721 return idx;
3722 }
3723
btf_find_datasec_var(const struct btf * btf,const struct btf_type * t,u32 field_mask,struct btf_field_info * info,int info_cnt,u32 level)3724 static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3725 u32 field_mask, struct btf_field_info *info,
3726 int info_cnt, u32 level)
3727 {
3728 int ret, idx = 0;
3729 const struct btf_var_secinfo *vsi;
3730 u32 i, off, seen_mask = 0;
3731
3732 for_each_vsi(i, t, vsi) {
3733 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3734 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3735
3736 off = vsi->offset;
3737 ret = btf_find_field_one(btf, var, var_type, -1, off, vsi->size,
3738 field_mask, &seen_mask,
3739 &info[idx], info_cnt - idx,
3740 level);
3741 if (ret < 0)
3742 return ret;
3743 idx += ret;
3744 }
3745 return idx;
3746 }
3747
btf_find_field(const struct btf * btf,const struct btf_type * t,u32 field_mask,struct btf_field_info * info,int info_cnt)3748 static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3749 u32 field_mask, struct btf_field_info *info,
3750 int info_cnt)
3751 {
3752 if (__btf_type_is_struct(t))
3753 return btf_find_struct_field(btf, t, field_mask, info, info_cnt, 0);
3754 else if (btf_type_is_datasec(t))
3755 return btf_find_datasec_var(btf, t, field_mask, info, info_cnt, 0);
3756 return -EINVAL;
3757 }
3758
3759 /* Callers have to ensure the life cycle of btf if it is program BTF */
btf_parse_kptr(const struct btf * btf,struct btf_field * field,struct btf_field_info * info)3760 static int btf_parse_kptr(const struct btf *btf, struct btf_field *field,
3761 struct btf_field_info *info)
3762 {
3763 struct module *mod = NULL;
3764 const struct btf_type *t;
3765 /* If a matching btf type is found in kernel or module BTFs, kptr_ref
3766 * is that BTF, otherwise it's program BTF
3767 */
3768 struct btf *kptr_btf;
3769 int ret;
3770 s32 id;
3771
3772 /* Find type in map BTF, and use it to look up the matching type
3773 * in vmlinux or module BTFs, by name and kind.
3774 */
3775 t = btf_type_by_id(btf, info->kptr.type_id);
3776 id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3777 &kptr_btf);
3778 if (id == -ENOENT) {
3779 /* btf_parse_kptr should only be called w/ btf = program BTF */
3780 WARN_ON_ONCE(btf_is_kernel(btf));
3781
3782 /* Type exists only in program BTF. Assume that it's a MEM_ALLOC
3783 * kptr allocated via bpf_obj_new
3784 */
3785 field->kptr.dtor = NULL;
3786 id = info->kptr.type_id;
3787 kptr_btf = (struct btf *)btf;
3788 goto found_dtor;
3789 }
3790 if (id < 0)
3791 return id;
3792
3793 /* Find and stash the function pointer for the destruction function that
3794 * needs to be eventually invoked from the map free path.
3795 */
3796 if (info->type == BPF_KPTR_REF) {
3797 const struct btf_type *dtor_func;
3798 const char *dtor_func_name;
3799 unsigned long addr;
3800 s32 dtor_btf_id;
3801
3802 /* This call also serves as a whitelist of allowed objects that
3803 * can be used as a referenced pointer and be stored in a map at
3804 * the same time.
3805 */
3806 dtor_btf_id = btf_find_dtor_kfunc(kptr_btf, id);
3807 if (dtor_btf_id < 0) {
3808 ret = dtor_btf_id;
3809 goto end_btf;
3810 }
3811
3812 dtor_func = btf_type_by_id(kptr_btf, dtor_btf_id);
3813 if (!dtor_func) {
3814 ret = -ENOENT;
3815 goto end_btf;
3816 }
3817
3818 if (btf_is_module(kptr_btf)) {
3819 mod = btf_try_get_module(kptr_btf);
3820 if (!mod) {
3821 ret = -ENXIO;
3822 goto end_btf;
3823 }
3824 }
3825
3826 /* We already verified dtor_func to be btf_type_is_func
3827 * in register_btf_id_dtor_kfuncs.
3828 */
3829 dtor_func_name = __btf_name_by_offset(kptr_btf, dtor_func->name_off);
3830 addr = kallsyms_lookup_name(dtor_func_name);
3831 if (!addr) {
3832 ret = -EINVAL;
3833 goto end_mod;
3834 }
3835 field->kptr.dtor = (void *)addr;
3836 }
3837
3838 found_dtor:
3839 field->kptr.btf_id = id;
3840 field->kptr.btf = kptr_btf;
3841 field->kptr.module = mod;
3842 return 0;
3843 end_mod:
3844 module_put(mod);
3845 end_btf:
3846 btf_put(kptr_btf);
3847 return ret;
3848 }
3849
btf_parse_graph_root(const struct btf * btf,struct btf_field * field,struct btf_field_info * info,const char * node_type_name,size_t node_type_align)3850 static int btf_parse_graph_root(const struct btf *btf,
3851 struct btf_field *field,
3852 struct btf_field_info *info,
3853 const char *node_type_name,
3854 size_t node_type_align)
3855 {
3856 const struct btf_type *t, *n = NULL;
3857 const struct btf_member *member;
3858 u32 offset;
3859 int i;
3860
3861 t = btf_type_by_id(btf, info->graph_root.value_btf_id);
3862 /* We've already checked that value_btf_id is a struct type. We
3863 * just need to figure out the offset of the list_node, and
3864 * verify its type.
3865 */
3866 for_each_member(i, t, member) {
3867 if (strcmp(info->graph_root.node_name,
3868 __btf_name_by_offset(btf, member->name_off)))
3869 continue;
3870 /* Invalid BTF, two members with same name */
3871 if (n)
3872 return -EINVAL;
3873 n = btf_type_by_id(btf, member->type);
3874 if (!__btf_type_is_struct(n))
3875 return -EINVAL;
3876 if (strcmp(node_type_name, __btf_name_by_offset(btf, n->name_off)))
3877 return -EINVAL;
3878 offset = __btf_member_bit_offset(n, member);
3879 if (offset % 8)
3880 return -EINVAL;
3881 offset /= 8;
3882 if (offset % node_type_align)
3883 return -EINVAL;
3884
3885 field->graph_root.btf = (struct btf *)btf;
3886 field->graph_root.value_btf_id = info->graph_root.value_btf_id;
3887 field->graph_root.node_offset = offset;
3888 }
3889 if (!n)
3890 return -ENOENT;
3891 return 0;
3892 }
3893
btf_parse_list_head(const struct btf * btf,struct btf_field * field,struct btf_field_info * info)3894 static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
3895 struct btf_field_info *info)
3896 {
3897 return btf_parse_graph_root(btf, field, info, "bpf_list_node",
3898 __alignof__(struct bpf_list_node));
3899 }
3900
btf_parse_rb_root(const struct btf * btf,struct btf_field * field,struct btf_field_info * info)3901 static int btf_parse_rb_root(const struct btf *btf, struct btf_field *field,
3902 struct btf_field_info *info)
3903 {
3904 return btf_parse_graph_root(btf, field, info, "bpf_rb_node",
3905 __alignof__(struct bpf_rb_node));
3906 }
3907
btf_field_cmp(const void * _a,const void * _b,const void * priv)3908 static int btf_field_cmp(const void *_a, const void *_b, const void *priv)
3909 {
3910 const struct btf_field *a = (const struct btf_field *)_a;
3911 const struct btf_field *b = (const struct btf_field *)_b;
3912
3913 if (a->offset < b->offset)
3914 return -1;
3915 else if (a->offset > b->offset)
3916 return 1;
3917 return 0;
3918 }
3919
btf_parse_fields(const struct btf * btf,const struct btf_type * t,u32 field_mask,u32 value_size)3920 struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
3921 u32 field_mask, u32 value_size)
3922 {
3923 struct btf_field_info info_arr[BTF_FIELDS_MAX];
3924 u32 next_off = 0, field_type_size;
3925 struct btf_record *rec;
3926 int ret, i, cnt;
3927
3928 ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
3929 if (ret < 0)
3930 return ERR_PTR(ret);
3931 if (!ret)
3932 return NULL;
3933
3934 cnt = ret;
3935 /* This needs to be kzalloc to zero out padding and unused fields, see
3936 * comment in btf_record_equal.
3937 */
3938 rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);
3939 if (!rec)
3940 return ERR_PTR(-ENOMEM);
3941
3942 rec->spin_lock_off = -EINVAL;
3943 rec->timer_off = -EINVAL;
3944 rec->wq_off = -EINVAL;
3945 rec->refcount_off = -EINVAL;
3946 for (i = 0; i < cnt; i++) {
3947 field_type_size = btf_field_type_size(info_arr[i].type);
3948 if (info_arr[i].off + field_type_size > value_size) {
3949 WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
3950 ret = -EFAULT;
3951 goto end;
3952 }
3953 if (info_arr[i].off < next_off) {
3954 ret = -EEXIST;
3955 goto end;
3956 }
3957 next_off = info_arr[i].off + field_type_size;
3958
3959 rec->field_mask |= info_arr[i].type;
3960 rec->fields[i].offset = info_arr[i].off;
3961 rec->fields[i].type = info_arr[i].type;
3962 rec->fields[i].size = field_type_size;
3963
3964 switch (info_arr[i].type) {
3965 case BPF_SPIN_LOCK:
3966 WARN_ON_ONCE(rec->spin_lock_off >= 0);
3967 /* Cache offset for faster lookup at runtime */
3968 rec->spin_lock_off = rec->fields[i].offset;
3969 break;
3970 case BPF_TIMER:
3971 WARN_ON_ONCE(rec->timer_off >= 0);
3972 /* Cache offset for faster lookup at runtime */
3973 rec->timer_off = rec->fields[i].offset;
3974 break;
3975 case BPF_WORKQUEUE:
3976 WARN_ON_ONCE(rec->wq_off >= 0);
3977 /* Cache offset for faster lookup at runtime */
3978 rec->wq_off = rec->fields[i].offset;
3979 break;
3980 case BPF_REFCOUNT:
3981 WARN_ON_ONCE(rec->refcount_off >= 0);
3982 /* Cache offset for faster lookup at runtime */
3983 rec->refcount_off = rec->fields[i].offset;
3984 break;
3985 case BPF_KPTR_UNREF:
3986 case BPF_KPTR_REF:
3987 case BPF_KPTR_PERCPU:
3988 ret = btf_parse_kptr(btf, &rec->fields[i], &info_arr[i]);
3989 if (ret < 0)
3990 goto end;
3991 break;
3992 case BPF_LIST_HEAD:
3993 ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
3994 if (ret < 0)
3995 goto end;
3996 break;
3997 case BPF_RB_ROOT:
3998 ret = btf_parse_rb_root(btf, &rec->fields[i], &info_arr[i]);
3999 if (ret < 0)
4000 goto end;
4001 break;
4002 case BPF_LIST_NODE:
4003 case BPF_RB_NODE:
4004 break;
4005 default:
4006 ret = -EFAULT;
4007 goto end;
4008 }
4009 rec->cnt++;
4010 }
4011
4012 /* bpf_{list_head, rb_node} require bpf_spin_lock */
4013 if ((btf_record_has_field(rec, BPF_LIST_HEAD) ||
4014 btf_record_has_field(rec, BPF_RB_ROOT)) && rec->spin_lock_off < 0) {
4015 ret = -EINVAL;
4016 goto end;
4017 }
4018
4019 if (rec->refcount_off < 0 &&
4020 btf_record_has_field(rec, BPF_LIST_NODE) &&
4021 btf_record_has_field(rec, BPF_RB_NODE)) {
4022 ret = -EINVAL;
4023 goto end;
4024 }
4025
4026 sort_r(rec->fields, rec->cnt, sizeof(struct btf_field), btf_field_cmp,
4027 NULL, rec);
4028
4029 return rec;
4030 end:
4031 btf_record_free(rec);
4032 return ERR_PTR(ret);
4033 }
4034
btf_check_and_fixup_fields(const struct btf * btf,struct btf_record * rec)4035 int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
4036 {
4037 int i;
4038
4039 /* There are three types that signify ownership of some other type:
4040 * kptr_ref, bpf_list_head, bpf_rb_root.
4041 * kptr_ref only supports storing kernel types, which can't store
4042 * references to program allocated local types.
4043 *
4044 * Hence we only need to ensure that bpf_{list_head,rb_root} ownership
4045 * does not form cycles.
4046 */
4047 if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & BPF_GRAPH_ROOT))
4048 return 0;
4049 for (i = 0; i < rec->cnt; i++) {
4050 struct btf_struct_meta *meta;
4051 u32 btf_id;
4052
4053 if (!(rec->fields[i].type & BPF_GRAPH_ROOT))
4054 continue;
4055 btf_id = rec->fields[i].graph_root.value_btf_id;
4056 meta = btf_find_struct_meta(btf, btf_id);
4057 if (!meta)
4058 return -EFAULT;
4059 rec->fields[i].graph_root.value_rec = meta->record;
4060
4061 /* We need to set value_rec for all root types, but no need
4062 * to check ownership cycle for a type unless it's also a
4063 * node type.
4064 */
4065 if (!(rec->field_mask & BPF_GRAPH_NODE))
4066 continue;
4067
4068 /* We need to ensure ownership acyclicity among all types. The
4069 * proper way to do it would be to topologically sort all BTF
4070 * IDs based on the ownership edges, since there can be multiple
4071 * bpf_{list_head,rb_node} in a type. Instead, we use the
4072 * following resaoning:
4073 *
4074 * - A type can only be owned by another type in user BTF if it
4075 * has a bpf_{list,rb}_node. Let's call these node types.
4076 * - A type can only _own_ another type in user BTF if it has a
4077 * bpf_{list_head,rb_root}. Let's call these root types.
4078 *
4079 * We ensure that if a type is both a root and node, its
4080 * element types cannot be root types.
4081 *
4082 * To ensure acyclicity:
4083 *
4084 * When A is an root type but not a node, its ownership
4085 * chain can be:
4086 * A -> B -> C
4087 * Where:
4088 * - A is an root, e.g. has bpf_rb_root.
4089 * - B is both a root and node, e.g. has bpf_rb_node and
4090 * bpf_list_head.
4091 * - C is only an root, e.g. has bpf_list_node
4092 *
4093 * When A is both a root and node, some other type already
4094 * owns it in the BTF domain, hence it can not own
4095 * another root type through any of the ownership edges.
4096 * A -> B
4097 * Where:
4098 * - A is both an root and node.
4099 * - B is only an node.
4100 */
4101 if (meta->record->field_mask & BPF_GRAPH_ROOT)
4102 return -ELOOP;
4103 }
4104 return 0;
4105 }
4106
__btf_struct_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)4107 static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
4108 u32 type_id, void *data, u8 bits_offset,
4109 struct btf_show *show)
4110 {
4111 const struct btf_member *member;
4112 void *safe_data;
4113 u32 i;
4114
4115 safe_data = btf_show_start_struct_type(show, t, type_id, data);
4116 if (!safe_data)
4117 return;
4118
4119 for_each_member(i, t, member) {
4120 const struct btf_type *member_type = btf_type_by_id(btf,
4121 member->type);
4122 const struct btf_kind_operations *ops;
4123 u32 member_offset, bitfield_size;
4124 u32 bytes_offset;
4125 u8 bits8_offset;
4126
4127 btf_show_start_member(show, member);
4128
4129 member_offset = __btf_member_bit_offset(t, member);
4130 bitfield_size = __btf_member_bitfield_size(t, member);
4131 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
4132 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
4133 if (bitfield_size) {
4134 safe_data = btf_show_start_type(show, member_type,
4135 member->type,
4136 data + bytes_offset);
4137 if (safe_data)
4138 btf_bitfield_show(safe_data,
4139 bits8_offset,
4140 bitfield_size, show);
4141 btf_show_end_type(show);
4142 } else {
4143 ops = btf_type_ops(member_type);
4144 ops->show(btf, member_type, member->type,
4145 data + bytes_offset, bits8_offset, show);
4146 }
4147
4148 btf_show_end_member(show);
4149 }
4150
4151 btf_show_end_struct_type(show);
4152 }
4153
btf_struct_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)4154 static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
4155 u32 type_id, void *data, u8 bits_offset,
4156 struct btf_show *show)
4157 {
4158 const struct btf_member *m = show->state.member;
4159
4160 /*
4161 * First check if any members would be shown (are non-zero).
4162 * See comments above "struct btf_show" definition for more
4163 * details on how this works at a high-level.
4164 */
4165 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
4166 if (!show->state.depth_check) {
4167 show->state.depth_check = show->state.depth + 1;
4168 show->state.depth_to_show = 0;
4169 }
4170 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
4171 /* Restore saved member data here */
4172 show->state.member = m;
4173 if (show->state.depth_check != show->state.depth + 1)
4174 return;
4175 show->state.depth_check = 0;
4176
4177 if (show->state.depth_to_show <= show->state.depth)
4178 return;
4179 /*
4180 * Reaching here indicates we have recursed and found
4181 * non-zero child values.
4182 */
4183 }
4184
4185 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
4186 }
4187
4188 static struct btf_kind_operations struct_ops = {
4189 .check_meta = btf_struct_check_meta,
4190 .resolve = btf_struct_resolve,
4191 .check_member = btf_struct_check_member,
4192 .check_kflag_member = btf_generic_check_kflag_member,
4193 .log_details = btf_struct_log,
4194 .show = btf_struct_show,
4195 };
4196
btf_enum_check_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)4197 static int btf_enum_check_member(struct btf_verifier_env *env,
4198 const struct btf_type *struct_type,
4199 const struct btf_member *member,
4200 const struct btf_type *member_type)
4201 {
4202 u32 struct_bits_off = member->offset;
4203 u32 struct_size, bytes_offset;
4204
4205 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4206 btf_verifier_log_member(env, struct_type, member,
4207 "Member is not byte aligned");
4208 return -EINVAL;
4209 }
4210
4211 struct_size = struct_type->size;
4212 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
4213 if (struct_size - bytes_offset < member_type->size) {
4214 btf_verifier_log_member(env, struct_type, member,
4215 "Member exceeds struct_size");
4216 return -EINVAL;
4217 }
4218
4219 return 0;
4220 }
4221
btf_enum_check_kflag_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)4222 static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
4223 const struct btf_type *struct_type,
4224 const struct btf_member *member,
4225 const struct btf_type *member_type)
4226 {
4227 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
4228 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
4229
4230 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
4231 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
4232 if (!nr_bits) {
4233 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4234 btf_verifier_log_member(env, struct_type, member,
4235 "Member is not byte aligned");
4236 return -EINVAL;
4237 }
4238
4239 nr_bits = int_bitsize;
4240 } else if (nr_bits > int_bitsize) {
4241 btf_verifier_log_member(env, struct_type, member,
4242 "Invalid member bitfield_size");
4243 return -EINVAL;
4244 }
4245
4246 struct_size = struct_type->size;
4247 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
4248 if (struct_size < bytes_end) {
4249 btf_verifier_log_member(env, struct_type, member,
4250 "Member exceeds struct_size");
4251 return -EINVAL;
4252 }
4253
4254 return 0;
4255 }
4256
btf_enum_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)4257 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
4258 const struct btf_type *t,
4259 u32 meta_left)
4260 {
4261 const struct btf_enum *enums = btf_type_enum(t);
4262 struct btf *btf = env->btf;
4263 const char *fmt_str;
4264 u16 i, nr_enums;
4265 u32 meta_needed;
4266
4267 nr_enums = btf_type_vlen(t);
4268 meta_needed = nr_enums * sizeof(*enums);
4269
4270 if (meta_left < meta_needed) {
4271 btf_verifier_log_basic(env, t,
4272 "meta_left:%u meta_needed:%u",
4273 meta_left, meta_needed);
4274 return -EINVAL;
4275 }
4276
4277 if (t->size > 8 || !is_power_of_2(t->size)) {
4278 btf_verifier_log_type(env, t, "Unexpected size");
4279 return -EINVAL;
4280 }
4281
4282 /* enum type either no name or a valid one */
4283 if (t->name_off &&
4284 !btf_name_valid_identifier(env->btf, t->name_off)) {
4285 btf_verifier_log_type(env, t, "Invalid name");
4286 return -EINVAL;
4287 }
4288
4289 btf_verifier_log_type(env, t, NULL);
4290
4291 for (i = 0; i < nr_enums; i++) {
4292 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4293 btf_verifier_log(env, "\tInvalid name_offset:%u",
4294 enums[i].name_off);
4295 return -EINVAL;
4296 }
4297
4298 /* enum member must have a valid name */
4299 if (!enums[i].name_off ||
4300 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4301 btf_verifier_log_type(env, t, "Invalid name");
4302 return -EINVAL;
4303 }
4304
4305 if (env->log.level == BPF_LOG_KERNEL)
4306 continue;
4307 fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
4308 btf_verifier_log(env, fmt_str,
4309 __btf_name_by_offset(btf, enums[i].name_off),
4310 enums[i].val);
4311 }
4312
4313 return meta_needed;
4314 }
4315
btf_enum_log(struct btf_verifier_env * env,const struct btf_type * t)4316 static void btf_enum_log(struct btf_verifier_env *env,
4317 const struct btf_type *t)
4318 {
4319 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4320 }
4321
btf_enum_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)4322 static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
4323 u32 type_id, void *data, u8 bits_offset,
4324 struct btf_show *show)
4325 {
4326 const struct btf_enum *enums = btf_type_enum(t);
4327 u32 i, nr_enums = btf_type_vlen(t);
4328 void *safe_data;
4329 int v;
4330
4331 safe_data = btf_show_start_type(show, t, type_id, data);
4332 if (!safe_data)
4333 return;
4334
4335 v = *(int *)safe_data;
4336
4337 for (i = 0; i < nr_enums; i++) {
4338 if (v != enums[i].val)
4339 continue;
4340
4341 btf_show_type_value(show, "%s",
4342 __btf_name_by_offset(btf,
4343 enums[i].name_off));
4344
4345 btf_show_end_type(show);
4346 return;
4347 }
4348
4349 if (btf_type_kflag(t))
4350 btf_show_type_value(show, "%d", v);
4351 else
4352 btf_show_type_value(show, "%u", v);
4353 btf_show_end_type(show);
4354 }
4355
4356 static struct btf_kind_operations enum_ops = {
4357 .check_meta = btf_enum_check_meta,
4358 .resolve = btf_df_resolve,
4359 .check_member = btf_enum_check_member,
4360 .check_kflag_member = btf_enum_check_kflag_member,
4361 .log_details = btf_enum_log,
4362 .show = btf_enum_show,
4363 };
4364
btf_enum64_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)4365 static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
4366 const struct btf_type *t,
4367 u32 meta_left)
4368 {
4369 const struct btf_enum64 *enums = btf_type_enum64(t);
4370 struct btf *btf = env->btf;
4371 const char *fmt_str;
4372 u16 i, nr_enums;
4373 u32 meta_needed;
4374
4375 nr_enums = btf_type_vlen(t);
4376 meta_needed = nr_enums * sizeof(*enums);
4377
4378 if (meta_left < meta_needed) {
4379 btf_verifier_log_basic(env, t,
4380 "meta_left:%u meta_needed:%u",
4381 meta_left, meta_needed);
4382 return -EINVAL;
4383 }
4384
4385 if (t->size > 8 || !is_power_of_2(t->size)) {
4386 btf_verifier_log_type(env, t, "Unexpected size");
4387 return -EINVAL;
4388 }
4389
4390 /* enum type either no name or a valid one */
4391 if (t->name_off &&
4392 !btf_name_valid_identifier(env->btf, t->name_off)) {
4393 btf_verifier_log_type(env, t, "Invalid name");
4394 return -EINVAL;
4395 }
4396
4397 btf_verifier_log_type(env, t, NULL);
4398
4399 for (i = 0; i < nr_enums; i++) {
4400 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4401 btf_verifier_log(env, "\tInvalid name_offset:%u",
4402 enums[i].name_off);
4403 return -EINVAL;
4404 }
4405
4406 /* enum member must have a valid name */
4407 if (!enums[i].name_off ||
4408 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4409 btf_verifier_log_type(env, t, "Invalid name");
4410 return -EINVAL;
4411 }
4412
4413 if (env->log.level == BPF_LOG_KERNEL)
4414 continue;
4415
4416 fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
4417 btf_verifier_log(env, fmt_str,
4418 __btf_name_by_offset(btf, enums[i].name_off),
4419 btf_enum64_value(enums + i));
4420 }
4421
4422 return meta_needed;
4423 }
4424
btf_enum64_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)4425 static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
4426 u32 type_id, void *data, u8 bits_offset,
4427 struct btf_show *show)
4428 {
4429 const struct btf_enum64 *enums = btf_type_enum64(t);
4430 u32 i, nr_enums = btf_type_vlen(t);
4431 void *safe_data;
4432 s64 v;
4433
4434 safe_data = btf_show_start_type(show, t, type_id, data);
4435 if (!safe_data)
4436 return;
4437
4438 v = *(u64 *)safe_data;
4439
4440 for (i = 0; i < nr_enums; i++) {
4441 if (v != btf_enum64_value(enums + i))
4442 continue;
4443
4444 btf_show_type_value(show, "%s",
4445 __btf_name_by_offset(btf,
4446 enums[i].name_off));
4447
4448 btf_show_end_type(show);
4449 return;
4450 }
4451
4452 if (btf_type_kflag(t))
4453 btf_show_type_value(show, "%lld", v);
4454 else
4455 btf_show_type_value(show, "%llu", v);
4456 btf_show_end_type(show);
4457 }
4458
4459 static struct btf_kind_operations enum64_ops = {
4460 .check_meta = btf_enum64_check_meta,
4461 .resolve = btf_df_resolve,
4462 .check_member = btf_enum_check_member,
4463 .check_kflag_member = btf_enum_check_kflag_member,
4464 .log_details = btf_enum_log,
4465 .show = btf_enum64_show,
4466 };
4467
btf_func_proto_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)4468 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
4469 const struct btf_type *t,
4470 u32 meta_left)
4471 {
4472 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
4473
4474 if (meta_left < meta_needed) {
4475 btf_verifier_log_basic(env, t,
4476 "meta_left:%u meta_needed:%u",
4477 meta_left, meta_needed);
4478 return -EINVAL;
4479 }
4480
4481 if (t->name_off) {
4482 btf_verifier_log_type(env, t, "Invalid name");
4483 return -EINVAL;
4484 }
4485
4486 if (btf_type_kflag(t)) {
4487 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4488 return -EINVAL;
4489 }
4490
4491 btf_verifier_log_type(env, t, NULL);
4492
4493 return meta_needed;
4494 }
4495
btf_func_proto_log(struct btf_verifier_env * env,const struct btf_type * t)4496 static void btf_func_proto_log(struct btf_verifier_env *env,
4497 const struct btf_type *t)
4498 {
4499 const struct btf_param *args = (const struct btf_param *)(t + 1);
4500 u16 nr_args = btf_type_vlen(t), i;
4501
4502 btf_verifier_log(env, "return=%u args=(", t->type);
4503 if (!nr_args) {
4504 btf_verifier_log(env, "void");
4505 goto done;
4506 }
4507
4508 if (nr_args == 1 && !args[0].type) {
4509 /* Only one vararg */
4510 btf_verifier_log(env, "vararg");
4511 goto done;
4512 }
4513
4514 btf_verifier_log(env, "%u %s", args[0].type,
4515 __btf_name_by_offset(env->btf,
4516 args[0].name_off));
4517 for (i = 1; i < nr_args - 1; i++)
4518 btf_verifier_log(env, ", %u %s", args[i].type,
4519 __btf_name_by_offset(env->btf,
4520 args[i].name_off));
4521
4522 if (nr_args > 1) {
4523 const struct btf_param *last_arg = &args[nr_args - 1];
4524
4525 if (last_arg->type)
4526 btf_verifier_log(env, ", %u %s", last_arg->type,
4527 __btf_name_by_offset(env->btf,
4528 last_arg->name_off));
4529 else
4530 btf_verifier_log(env, ", vararg");
4531 }
4532
4533 done:
4534 btf_verifier_log(env, ")");
4535 }
4536
4537 static struct btf_kind_operations func_proto_ops = {
4538 .check_meta = btf_func_proto_check_meta,
4539 .resolve = btf_df_resolve,
4540 /*
4541 * BTF_KIND_FUNC_PROTO cannot be directly referred by
4542 * a struct's member.
4543 *
4544 * It should be a function pointer instead.
4545 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
4546 *
4547 * Hence, there is no btf_func_check_member().
4548 */
4549 .check_member = btf_df_check_member,
4550 .check_kflag_member = btf_df_check_kflag_member,
4551 .log_details = btf_func_proto_log,
4552 .show = btf_df_show,
4553 };
4554
btf_func_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)4555 static s32 btf_func_check_meta(struct btf_verifier_env *env,
4556 const struct btf_type *t,
4557 u32 meta_left)
4558 {
4559 if (!t->name_off ||
4560 !btf_name_valid_identifier(env->btf, t->name_off)) {
4561 btf_verifier_log_type(env, t, "Invalid name");
4562 return -EINVAL;
4563 }
4564
4565 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
4566 btf_verifier_log_type(env, t, "Invalid func linkage");
4567 return -EINVAL;
4568 }
4569
4570 if (btf_type_kflag(t)) {
4571 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4572 return -EINVAL;
4573 }
4574
4575 btf_verifier_log_type(env, t, NULL);
4576
4577 return 0;
4578 }
4579
btf_func_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)4580 static int btf_func_resolve(struct btf_verifier_env *env,
4581 const struct resolve_vertex *v)
4582 {
4583 const struct btf_type *t = v->t;
4584 u32 next_type_id = t->type;
4585 int err;
4586
4587 err = btf_func_check(env, t);
4588 if (err)
4589 return err;
4590
4591 env_stack_pop_resolved(env, next_type_id, 0);
4592 return 0;
4593 }
4594
4595 static struct btf_kind_operations func_ops = {
4596 .check_meta = btf_func_check_meta,
4597 .resolve = btf_func_resolve,
4598 .check_member = btf_df_check_member,
4599 .check_kflag_member = btf_df_check_kflag_member,
4600 .log_details = btf_ref_type_log,
4601 .show = btf_df_show,
4602 };
4603
btf_var_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)4604 static s32 btf_var_check_meta(struct btf_verifier_env *env,
4605 const struct btf_type *t,
4606 u32 meta_left)
4607 {
4608 const struct btf_var *var;
4609 u32 meta_needed = sizeof(*var);
4610
4611 if (meta_left < meta_needed) {
4612 btf_verifier_log_basic(env, t,
4613 "meta_left:%u meta_needed:%u",
4614 meta_left, meta_needed);
4615 return -EINVAL;
4616 }
4617
4618 if (btf_type_vlen(t)) {
4619 btf_verifier_log_type(env, t, "vlen != 0");
4620 return -EINVAL;
4621 }
4622
4623 if (btf_type_kflag(t)) {
4624 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4625 return -EINVAL;
4626 }
4627
4628 if (!t->name_off ||
4629 !btf_name_valid_identifier(env->btf, t->name_off)) {
4630 btf_verifier_log_type(env, t, "Invalid name");
4631 return -EINVAL;
4632 }
4633
4634 /* A var cannot be in type void */
4635 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4636 btf_verifier_log_type(env, t, "Invalid type_id");
4637 return -EINVAL;
4638 }
4639
4640 var = btf_type_var(t);
4641 if (var->linkage != BTF_VAR_STATIC &&
4642 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4643 btf_verifier_log_type(env, t, "Linkage not supported");
4644 return -EINVAL;
4645 }
4646
4647 btf_verifier_log_type(env, t, NULL);
4648
4649 return meta_needed;
4650 }
4651
btf_var_log(struct btf_verifier_env * env,const struct btf_type * t)4652 static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4653 {
4654 const struct btf_var *var = btf_type_var(t);
4655
4656 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4657 }
4658
4659 static const struct btf_kind_operations var_ops = {
4660 .check_meta = btf_var_check_meta,
4661 .resolve = btf_var_resolve,
4662 .check_member = btf_df_check_member,
4663 .check_kflag_member = btf_df_check_kflag_member,
4664 .log_details = btf_var_log,
4665 .show = btf_var_show,
4666 };
4667
btf_datasec_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)4668 static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4669 const struct btf_type *t,
4670 u32 meta_left)
4671 {
4672 const struct btf_var_secinfo *vsi;
4673 u64 last_vsi_end_off = 0, sum = 0;
4674 u32 i, meta_needed;
4675
4676 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4677 if (meta_left < meta_needed) {
4678 btf_verifier_log_basic(env, t,
4679 "meta_left:%u meta_needed:%u",
4680 meta_left, meta_needed);
4681 return -EINVAL;
4682 }
4683
4684 if (!t->size) {
4685 btf_verifier_log_type(env, t, "size == 0");
4686 return -EINVAL;
4687 }
4688
4689 if (btf_type_kflag(t)) {
4690 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4691 return -EINVAL;
4692 }
4693
4694 if (!t->name_off ||
4695 !btf_name_valid_section(env->btf, t->name_off)) {
4696 btf_verifier_log_type(env, t, "Invalid name");
4697 return -EINVAL;
4698 }
4699
4700 btf_verifier_log_type(env, t, NULL);
4701
4702 for_each_vsi(i, t, vsi) {
4703 /* A var cannot be in type void */
4704 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4705 btf_verifier_log_vsi(env, t, vsi,
4706 "Invalid type_id");
4707 return -EINVAL;
4708 }
4709
4710 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4711 btf_verifier_log_vsi(env, t, vsi,
4712 "Invalid offset");
4713 return -EINVAL;
4714 }
4715
4716 if (!vsi->size || vsi->size > t->size) {
4717 btf_verifier_log_vsi(env, t, vsi,
4718 "Invalid size");
4719 return -EINVAL;
4720 }
4721
4722 last_vsi_end_off = vsi->offset + vsi->size;
4723 if (last_vsi_end_off > t->size) {
4724 btf_verifier_log_vsi(env, t, vsi,
4725 "Invalid offset+size");
4726 return -EINVAL;
4727 }
4728
4729 btf_verifier_log_vsi(env, t, vsi, NULL);
4730 sum += vsi->size;
4731 }
4732
4733 if (t->size < sum) {
4734 btf_verifier_log_type(env, t, "Invalid btf_info size");
4735 return -EINVAL;
4736 }
4737
4738 return meta_needed;
4739 }
4740
btf_datasec_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)4741 static int btf_datasec_resolve(struct btf_verifier_env *env,
4742 const struct resolve_vertex *v)
4743 {
4744 const struct btf_var_secinfo *vsi;
4745 struct btf *btf = env->btf;
4746 u16 i;
4747
4748 env->resolve_mode = RESOLVE_TBD;
4749 for_each_vsi_from(i, v->next_member, v->t, vsi) {
4750 u32 var_type_id = vsi->type, type_id, type_size = 0;
4751 const struct btf_type *var_type = btf_type_by_id(env->btf,
4752 var_type_id);
4753 if (!var_type || !btf_type_is_var(var_type)) {
4754 btf_verifier_log_vsi(env, v->t, vsi,
4755 "Not a VAR kind member");
4756 return -EINVAL;
4757 }
4758
4759 if (!env_type_is_resolve_sink(env, var_type) &&
4760 !env_type_is_resolved(env, var_type_id)) {
4761 env_stack_set_next_member(env, i + 1);
4762 return env_stack_push(env, var_type, var_type_id);
4763 }
4764
4765 type_id = var_type->type;
4766 if (!btf_type_id_size(btf, &type_id, &type_size)) {
4767 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4768 return -EINVAL;
4769 }
4770
4771 if (vsi->size < type_size) {
4772 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4773 return -EINVAL;
4774 }
4775 }
4776
4777 env_stack_pop_resolved(env, 0, 0);
4778 return 0;
4779 }
4780
btf_datasec_log(struct btf_verifier_env * env,const struct btf_type * t)4781 static void btf_datasec_log(struct btf_verifier_env *env,
4782 const struct btf_type *t)
4783 {
4784 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4785 }
4786
btf_datasec_show(const struct btf * btf,const struct btf_type * t,u32 type_id,void * data,u8 bits_offset,struct btf_show * show)4787 static void btf_datasec_show(const struct btf *btf,
4788 const struct btf_type *t, u32 type_id,
4789 void *data, u8 bits_offset,
4790 struct btf_show *show)
4791 {
4792 const struct btf_var_secinfo *vsi;
4793 const struct btf_type *var;
4794 u32 i;
4795
4796 if (!btf_show_start_type(show, t, type_id, data))
4797 return;
4798
4799 btf_show_type_value(show, "section (\"%s\") = {",
4800 __btf_name_by_offset(btf, t->name_off));
4801 for_each_vsi(i, t, vsi) {
4802 var = btf_type_by_id(btf, vsi->type);
4803 if (i)
4804 btf_show(show, ",");
4805 btf_type_ops(var)->show(btf, var, vsi->type,
4806 data + vsi->offset, bits_offset, show);
4807 }
4808 btf_show_end_type(show);
4809 }
4810
4811 static const struct btf_kind_operations datasec_ops = {
4812 .check_meta = btf_datasec_check_meta,
4813 .resolve = btf_datasec_resolve,
4814 .check_member = btf_df_check_member,
4815 .check_kflag_member = btf_df_check_kflag_member,
4816 .log_details = btf_datasec_log,
4817 .show = btf_datasec_show,
4818 };
4819
btf_float_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)4820 static s32 btf_float_check_meta(struct btf_verifier_env *env,
4821 const struct btf_type *t,
4822 u32 meta_left)
4823 {
4824 if (btf_type_vlen(t)) {
4825 btf_verifier_log_type(env, t, "vlen != 0");
4826 return -EINVAL;
4827 }
4828
4829 if (btf_type_kflag(t)) {
4830 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4831 return -EINVAL;
4832 }
4833
4834 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4835 t->size != 16) {
4836 btf_verifier_log_type(env, t, "Invalid type_size");
4837 return -EINVAL;
4838 }
4839
4840 btf_verifier_log_type(env, t, NULL);
4841
4842 return 0;
4843 }
4844
btf_float_check_member(struct btf_verifier_env * env,const struct btf_type * struct_type,const struct btf_member * member,const struct btf_type * member_type)4845 static int btf_float_check_member(struct btf_verifier_env *env,
4846 const struct btf_type *struct_type,
4847 const struct btf_member *member,
4848 const struct btf_type *member_type)
4849 {
4850 u64 start_offset_bytes;
4851 u64 end_offset_bytes;
4852 u64 misalign_bits;
4853 u64 align_bytes;
4854 u64 align_bits;
4855
4856 /* Different architectures have different alignment requirements, so
4857 * here we check only for the reasonable minimum. This way we ensure
4858 * that types after CO-RE can pass the kernel BTF verifier.
4859 */
4860 align_bytes = min_t(u64, sizeof(void *), member_type->size);
4861 align_bits = align_bytes * BITS_PER_BYTE;
4862 div64_u64_rem(member->offset, align_bits, &misalign_bits);
4863 if (misalign_bits) {
4864 btf_verifier_log_member(env, struct_type, member,
4865 "Member is not properly aligned");
4866 return -EINVAL;
4867 }
4868
4869 start_offset_bytes = member->offset / BITS_PER_BYTE;
4870 end_offset_bytes = start_offset_bytes + member_type->size;
4871 if (end_offset_bytes > struct_type->size) {
4872 btf_verifier_log_member(env, struct_type, member,
4873 "Member exceeds struct_size");
4874 return -EINVAL;
4875 }
4876
4877 return 0;
4878 }
4879
btf_float_log(struct btf_verifier_env * env,const struct btf_type * t)4880 static void btf_float_log(struct btf_verifier_env *env,
4881 const struct btf_type *t)
4882 {
4883 btf_verifier_log(env, "size=%u", t->size);
4884 }
4885
4886 static const struct btf_kind_operations float_ops = {
4887 .check_meta = btf_float_check_meta,
4888 .resolve = btf_df_resolve,
4889 .check_member = btf_float_check_member,
4890 .check_kflag_member = btf_generic_check_kflag_member,
4891 .log_details = btf_float_log,
4892 .show = btf_df_show,
4893 };
4894
btf_decl_tag_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)4895 static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4896 const struct btf_type *t,
4897 u32 meta_left)
4898 {
4899 const struct btf_decl_tag *tag;
4900 u32 meta_needed = sizeof(*tag);
4901 s32 component_idx;
4902 const char *value;
4903
4904 if (meta_left < meta_needed) {
4905 btf_verifier_log_basic(env, t,
4906 "meta_left:%u meta_needed:%u",
4907 meta_left, meta_needed);
4908 return -EINVAL;
4909 }
4910
4911 value = btf_name_by_offset(env->btf, t->name_off);
4912 if (!value || !value[0]) {
4913 btf_verifier_log_type(env, t, "Invalid value");
4914 return -EINVAL;
4915 }
4916
4917 if (btf_type_vlen(t)) {
4918 btf_verifier_log_type(env, t, "vlen != 0");
4919 return -EINVAL;
4920 }
4921
4922 if (btf_type_kflag(t)) {
4923 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4924 return -EINVAL;
4925 }
4926
4927 component_idx = btf_type_decl_tag(t)->component_idx;
4928 if (component_idx < -1) {
4929 btf_verifier_log_type(env, t, "Invalid component_idx");
4930 return -EINVAL;
4931 }
4932
4933 btf_verifier_log_type(env, t, NULL);
4934
4935 return meta_needed;
4936 }
4937
btf_decl_tag_resolve(struct btf_verifier_env * env,const struct resolve_vertex * v)4938 static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4939 const struct resolve_vertex *v)
4940 {
4941 const struct btf_type *next_type;
4942 const struct btf_type *t = v->t;
4943 u32 next_type_id = t->type;
4944 struct btf *btf = env->btf;
4945 s32 component_idx;
4946 u32 vlen;
4947
4948 next_type = btf_type_by_id(btf, next_type_id);
4949 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4950 btf_verifier_log_type(env, v->t, "Invalid type_id");
4951 return -EINVAL;
4952 }
4953
4954 if (!env_type_is_resolve_sink(env, next_type) &&
4955 !env_type_is_resolved(env, next_type_id))
4956 return env_stack_push(env, next_type, next_type_id);
4957
4958 component_idx = btf_type_decl_tag(t)->component_idx;
4959 if (component_idx != -1) {
4960 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4961 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4962 return -EINVAL;
4963 }
4964
4965 if (btf_type_is_struct(next_type)) {
4966 vlen = btf_type_vlen(next_type);
4967 } else {
4968 /* next_type should be a function */
4969 next_type = btf_type_by_id(btf, next_type->type);
4970 vlen = btf_type_vlen(next_type);
4971 }
4972
4973 if ((u32)component_idx >= vlen) {
4974 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4975 return -EINVAL;
4976 }
4977 }
4978
4979 env_stack_pop_resolved(env, next_type_id, 0);
4980
4981 return 0;
4982 }
4983
btf_decl_tag_log(struct btf_verifier_env * env,const struct btf_type * t)4984 static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
4985 {
4986 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
4987 btf_type_decl_tag(t)->component_idx);
4988 }
4989
4990 static const struct btf_kind_operations decl_tag_ops = {
4991 .check_meta = btf_decl_tag_check_meta,
4992 .resolve = btf_decl_tag_resolve,
4993 .check_member = btf_df_check_member,
4994 .check_kflag_member = btf_df_check_kflag_member,
4995 .log_details = btf_decl_tag_log,
4996 .show = btf_df_show,
4997 };
4998
btf_func_proto_check(struct btf_verifier_env * env,const struct btf_type * t)4999 static int btf_func_proto_check(struct btf_verifier_env *env,
5000 const struct btf_type *t)
5001 {
5002 const struct btf_type *ret_type;
5003 const struct btf_param *args;
5004 const struct btf *btf;
5005 u16 nr_args, i;
5006 int err;
5007
5008 btf = env->btf;
5009 args = (const struct btf_param *)(t + 1);
5010 nr_args = btf_type_vlen(t);
5011
5012 /* Check func return type which could be "void" (t->type == 0) */
5013 if (t->type) {
5014 u32 ret_type_id = t->type;
5015
5016 ret_type = btf_type_by_id(btf, ret_type_id);
5017 if (!ret_type) {
5018 btf_verifier_log_type(env, t, "Invalid return type");
5019 return -EINVAL;
5020 }
5021
5022 if (btf_type_is_resolve_source_only(ret_type)) {
5023 btf_verifier_log_type(env, t, "Invalid return type");
5024 return -EINVAL;
5025 }
5026
5027 if (btf_type_needs_resolve(ret_type) &&
5028 !env_type_is_resolved(env, ret_type_id)) {
5029 err = btf_resolve(env, ret_type, ret_type_id);
5030 if (err)
5031 return err;
5032 }
5033
5034 /* Ensure the return type is a type that has a size */
5035 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
5036 btf_verifier_log_type(env, t, "Invalid return type");
5037 return -EINVAL;
5038 }
5039 }
5040
5041 if (!nr_args)
5042 return 0;
5043
5044 /* Last func arg type_id could be 0 if it is a vararg */
5045 if (!args[nr_args - 1].type) {
5046 if (args[nr_args - 1].name_off) {
5047 btf_verifier_log_type(env, t, "Invalid arg#%u",
5048 nr_args);
5049 return -EINVAL;
5050 }
5051 nr_args--;
5052 }
5053
5054 for (i = 0; i < nr_args; i++) {
5055 const struct btf_type *arg_type;
5056 u32 arg_type_id;
5057
5058 arg_type_id = args[i].type;
5059 arg_type = btf_type_by_id(btf, arg_type_id);
5060 if (!arg_type) {
5061 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5062 return -EINVAL;
5063 }
5064
5065 if (btf_type_is_resolve_source_only(arg_type)) {
5066 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5067 return -EINVAL;
5068 }
5069
5070 if (args[i].name_off &&
5071 (!btf_name_offset_valid(btf, args[i].name_off) ||
5072 !btf_name_valid_identifier(btf, args[i].name_off))) {
5073 btf_verifier_log_type(env, t,
5074 "Invalid arg#%u", i + 1);
5075 return -EINVAL;
5076 }
5077
5078 if (btf_type_needs_resolve(arg_type) &&
5079 !env_type_is_resolved(env, arg_type_id)) {
5080 err = btf_resolve(env, arg_type, arg_type_id);
5081 if (err)
5082 return err;
5083 }
5084
5085 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
5086 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5087 return -EINVAL;
5088 }
5089 }
5090
5091 return 0;
5092 }
5093
btf_func_check(struct btf_verifier_env * env,const struct btf_type * t)5094 static int btf_func_check(struct btf_verifier_env *env,
5095 const struct btf_type *t)
5096 {
5097 const struct btf_type *proto_type;
5098 const struct btf_param *args;
5099 const struct btf *btf;
5100 u16 nr_args, i;
5101
5102 btf = env->btf;
5103 proto_type = btf_type_by_id(btf, t->type);
5104
5105 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
5106 btf_verifier_log_type(env, t, "Invalid type_id");
5107 return -EINVAL;
5108 }
5109
5110 args = (const struct btf_param *)(proto_type + 1);
5111 nr_args = btf_type_vlen(proto_type);
5112 for (i = 0; i < nr_args; i++) {
5113 if (!args[i].name_off && args[i].type) {
5114 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5115 return -EINVAL;
5116 }
5117 }
5118
5119 return 0;
5120 }
5121
5122 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
5123 [BTF_KIND_INT] = &int_ops,
5124 [BTF_KIND_PTR] = &ptr_ops,
5125 [BTF_KIND_ARRAY] = &array_ops,
5126 [BTF_KIND_STRUCT] = &struct_ops,
5127 [BTF_KIND_UNION] = &struct_ops,
5128 [BTF_KIND_ENUM] = &enum_ops,
5129 [BTF_KIND_FWD] = &fwd_ops,
5130 [BTF_KIND_TYPEDEF] = &modifier_ops,
5131 [BTF_KIND_VOLATILE] = &modifier_ops,
5132 [BTF_KIND_CONST] = &modifier_ops,
5133 [BTF_KIND_RESTRICT] = &modifier_ops,
5134 [BTF_KIND_FUNC] = &func_ops,
5135 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
5136 [BTF_KIND_VAR] = &var_ops,
5137 [BTF_KIND_DATASEC] = &datasec_ops,
5138 [BTF_KIND_FLOAT] = &float_ops,
5139 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
5140 [BTF_KIND_TYPE_TAG] = &modifier_ops,
5141 [BTF_KIND_ENUM64] = &enum64_ops,
5142 };
5143
btf_check_meta(struct btf_verifier_env * env,const struct btf_type * t,u32 meta_left)5144 static s32 btf_check_meta(struct btf_verifier_env *env,
5145 const struct btf_type *t,
5146 u32 meta_left)
5147 {
5148 u32 saved_meta_left = meta_left;
5149 s32 var_meta_size;
5150
5151 if (meta_left < sizeof(*t)) {
5152 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
5153 env->log_type_id, meta_left, sizeof(*t));
5154 return -EINVAL;
5155 }
5156 meta_left -= sizeof(*t);
5157
5158 if (t->info & ~BTF_INFO_MASK) {
5159 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
5160 env->log_type_id, t->info);
5161 return -EINVAL;
5162 }
5163
5164 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
5165 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
5166 btf_verifier_log(env, "[%u] Invalid kind:%u",
5167 env->log_type_id, BTF_INFO_KIND(t->info));
5168 return -EINVAL;
5169 }
5170
5171 if (!btf_name_offset_valid(env->btf, t->name_off)) {
5172 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
5173 env->log_type_id, t->name_off);
5174 return -EINVAL;
5175 }
5176
5177 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
5178 if (var_meta_size < 0)
5179 return var_meta_size;
5180
5181 meta_left -= var_meta_size;
5182
5183 return saved_meta_left - meta_left;
5184 }
5185
btf_check_all_metas(struct btf_verifier_env * env)5186 static int btf_check_all_metas(struct btf_verifier_env *env)
5187 {
5188 struct btf *btf = env->btf;
5189 struct btf_header *hdr;
5190 void *cur, *end;
5191
5192 hdr = &btf->hdr;
5193 cur = btf->nohdr_data + hdr->type_off;
5194 end = cur + hdr->type_len;
5195
5196 env->log_type_id = btf->base_btf ? btf->start_id : 1;
5197 while (cur < end) {
5198 struct btf_type *t = cur;
5199 s32 meta_size;
5200
5201 meta_size = btf_check_meta(env, t, end - cur);
5202 if (meta_size < 0)
5203 return meta_size;
5204
5205 btf_add_type(env, t);
5206 cur += meta_size;
5207 env->log_type_id++;
5208 }
5209
5210 return 0;
5211 }
5212
btf_resolve_valid(struct btf_verifier_env * env,const struct btf_type * t,u32 type_id)5213 static bool btf_resolve_valid(struct btf_verifier_env *env,
5214 const struct btf_type *t,
5215 u32 type_id)
5216 {
5217 struct btf *btf = env->btf;
5218
5219 if (!env_type_is_resolved(env, type_id))
5220 return false;
5221
5222 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
5223 return !btf_resolved_type_id(btf, type_id) &&
5224 !btf_resolved_type_size(btf, type_id);
5225
5226 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
5227 return btf_resolved_type_id(btf, type_id) &&
5228 !btf_resolved_type_size(btf, type_id);
5229
5230 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
5231 btf_type_is_var(t)) {
5232 t = btf_type_id_resolve(btf, &type_id);
5233 return t &&
5234 !btf_type_is_modifier(t) &&
5235 !btf_type_is_var(t) &&
5236 !btf_type_is_datasec(t);
5237 }
5238
5239 if (btf_type_is_array(t)) {
5240 const struct btf_array *array = btf_type_array(t);
5241 const struct btf_type *elem_type;
5242 u32 elem_type_id = array->type;
5243 u32 elem_size;
5244
5245 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
5246 return elem_type && !btf_type_is_modifier(elem_type) &&
5247 (array->nelems * elem_size ==
5248 btf_resolved_type_size(btf, type_id));
5249 }
5250
5251 return false;
5252 }
5253
btf_resolve(struct btf_verifier_env * env,const struct btf_type * t,u32 type_id)5254 static int btf_resolve(struct btf_verifier_env *env,
5255 const struct btf_type *t, u32 type_id)
5256 {
5257 u32 save_log_type_id = env->log_type_id;
5258 const struct resolve_vertex *v;
5259 int err = 0;
5260
5261 env->resolve_mode = RESOLVE_TBD;
5262 env_stack_push(env, t, type_id);
5263 while (!err && (v = env_stack_peak(env))) {
5264 env->log_type_id = v->type_id;
5265 err = btf_type_ops(v->t)->resolve(env, v);
5266 }
5267
5268 env->log_type_id = type_id;
5269 if (err == -E2BIG) {
5270 btf_verifier_log_type(env, t,
5271 "Exceeded max resolving depth:%u",
5272 MAX_RESOLVE_DEPTH);
5273 } else if (err == -EEXIST) {
5274 btf_verifier_log_type(env, t, "Loop detected");
5275 }
5276
5277 /* Final sanity check */
5278 if (!err && !btf_resolve_valid(env, t, type_id)) {
5279 btf_verifier_log_type(env, t, "Invalid resolve state");
5280 err = -EINVAL;
5281 }
5282
5283 env->log_type_id = save_log_type_id;
5284 return err;
5285 }
5286
btf_check_all_types(struct btf_verifier_env * env)5287 static int btf_check_all_types(struct btf_verifier_env *env)
5288 {
5289 struct btf *btf = env->btf;
5290 const struct btf_type *t;
5291 u32 type_id, i;
5292 int err;
5293
5294 err = env_resolve_init(env);
5295 if (err)
5296 return err;
5297
5298 env->phase++;
5299 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
5300 type_id = btf->start_id + i;
5301 t = btf_type_by_id(btf, type_id);
5302
5303 env->log_type_id = type_id;
5304 if (btf_type_needs_resolve(t) &&
5305 !env_type_is_resolved(env, type_id)) {
5306 err = btf_resolve(env, t, type_id);
5307 if (err)
5308 return err;
5309 }
5310
5311 if (btf_type_is_func_proto(t)) {
5312 err = btf_func_proto_check(env, t);
5313 if (err)
5314 return err;
5315 }
5316 }
5317
5318 return 0;
5319 }
5320
btf_parse_type_sec(struct btf_verifier_env * env)5321 static int btf_parse_type_sec(struct btf_verifier_env *env)
5322 {
5323 const struct btf_header *hdr = &env->btf->hdr;
5324 int err;
5325
5326 /* Type section must align to 4 bytes */
5327 if (hdr->type_off & (sizeof(u32) - 1)) {
5328 btf_verifier_log(env, "Unaligned type_off");
5329 return -EINVAL;
5330 }
5331
5332 if (!env->btf->base_btf && !hdr->type_len) {
5333 btf_verifier_log(env, "No type found");
5334 return -EINVAL;
5335 }
5336
5337 err = btf_check_all_metas(env);
5338 if (err)
5339 return err;
5340
5341 return btf_check_all_types(env);
5342 }
5343
btf_parse_str_sec(struct btf_verifier_env * env)5344 static int btf_parse_str_sec(struct btf_verifier_env *env)
5345 {
5346 const struct btf_header *hdr;
5347 struct btf *btf = env->btf;
5348 const char *start, *end;
5349
5350 hdr = &btf->hdr;
5351 start = btf->nohdr_data + hdr->str_off;
5352 end = start + hdr->str_len;
5353
5354 if (end != btf->data + btf->data_size) {
5355 btf_verifier_log(env, "String section is not at the end");
5356 return -EINVAL;
5357 }
5358
5359 btf->strings = start;
5360
5361 if (btf->base_btf && !hdr->str_len)
5362 return 0;
5363 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
5364 btf_verifier_log(env, "Invalid string section");
5365 return -EINVAL;
5366 }
5367 if (!btf->base_btf && start[0]) {
5368 btf_verifier_log(env, "Invalid string section");
5369 return -EINVAL;
5370 }
5371
5372 return 0;
5373 }
5374
5375 static const size_t btf_sec_info_offset[] = {
5376 offsetof(struct btf_header, type_off),
5377 offsetof(struct btf_header, str_off),
5378 };
5379
btf_sec_info_cmp(const void * a,const void * b)5380 static int btf_sec_info_cmp(const void *a, const void *b)
5381 {
5382 const struct btf_sec_info *x = a;
5383 const struct btf_sec_info *y = b;
5384
5385 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
5386 }
5387
btf_check_sec_info(struct btf_verifier_env * env,u32 btf_data_size)5388 static int btf_check_sec_info(struct btf_verifier_env *env,
5389 u32 btf_data_size)
5390 {
5391 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
5392 u32 total, expected_total, i;
5393 const struct btf_header *hdr;
5394 const struct btf *btf;
5395
5396 btf = env->btf;
5397 hdr = &btf->hdr;
5398
5399 /* Populate the secs from hdr */
5400 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
5401 secs[i] = *(struct btf_sec_info *)((void *)hdr +
5402 btf_sec_info_offset[i]);
5403
5404 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
5405 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
5406
5407 /* Check for gaps and overlap among sections */
5408 total = 0;
5409 expected_total = btf_data_size - hdr->hdr_len;
5410 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
5411 if (expected_total < secs[i].off) {
5412 btf_verifier_log(env, "Invalid section offset");
5413 return -EINVAL;
5414 }
5415 if (total < secs[i].off) {
5416 /* gap */
5417 btf_verifier_log(env, "Unsupported section found");
5418 return -EINVAL;
5419 }
5420 if (total > secs[i].off) {
5421 btf_verifier_log(env, "Section overlap found");
5422 return -EINVAL;
5423 }
5424 if (expected_total - total < secs[i].len) {
5425 btf_verifier_log(env,
5426 "Total section length too long");
5427 return -EINVAL;
5428 }
5429 total += secs[i].len;
5430 }
5431
5432 /* There is data other than hdr and known sections */
5433 if (expected_total != total) {
5434 btf_verifier_log(env, "Unsupported section found");
5435 return -EINVAL;
5436 }
5437
5438 return 0;
5439 }
5440
btf_parse_hdr(struct btf_verifier_env * env)5441 static int btf_parse_hdr(struct btf_verifier_env *env)
5442 {
5443 u32 hdr_len, hdr_copy, btf_data_size;
5444 const struct btf_header *hdr;
5445 struct btf *btf;
5446
5447 btf = env->btf;
5448 btf_data_size = btf->data_size;
5449
5450 if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
5451 btf_verifier_log(env, "hdr_len not found");
5452 return -EINVAL;
5453 }
5454
5455 hdr = btf->data;
5456 hdr_len = hdr->hdr_len;
5457 if (btf_data_size < hdr_len) {
5458 btf_verifier_log(env, "btf_header not found");
5459 return -EINVAL;
5460 }
5461
5462 /* Ensure the unsupported header fields are zero */
5463 if (hdr_len > sizeof(btf->hdr)) {
5464 u8 *expected_zero = btf->data + sizeof(btf->hdr);
5465 u8 *end = btf->data + hdr_len;
5466
5467 for (; expected_zero < end; expected_zero++) {
5468 if (*expected_zero) {
5469 btf_verifier_log(env, "Unsupported btf_header");
5470 return -E2BIG;
5471 }
5472 }
5473 }
5474
5475 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
5476 memcpy(&btf->hdr, btf->data, hdr_copy);
5477
5478 hdr = &btf->hdr;
5479
5480 btf_verifier_log_hdr(env, btf_data_size);
5481
5482 if (hdr->magic != BTF_MAGIC) {
5483 btf_verifier_log(env, "Invalid magic");
5484 return -EINVAL;
5485 }
5486
5487 if (hdr->version != BTF_VERSION) {
5488 btf_verifier_log(env, "Unsupported version");
5489 return -ENOTSUPP;
5490 }
5491
5492 if (hdr->flags) {
5493 btf_verifier_log(env, "Unsupported flags");
5494 return -ENOTSUPP;
5495 }
5496
5497 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
5498 btf_verifier_log(env, "No data");
5499 return -EINVAL;
5500 }
5501
5502 return btf_check_sec_info(env, btf_data_size);
5503 }
5504
5505 static const char *alloc_obj_fields[] = {
5506 "bpf_spin_lock",
5507 "bpf_list_head",
5508 "bpf_list_node",
5509 "bpf_rb_root",
5510 "bpf_rb_node",
5511 "bpf_refcount",
5512 };
5513
5514 static struct btf_struct_metas *
btf_parse_struct_metas(struct bpf_verifier_log * log,struct btf * btf)5515 btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
5516 {
5517 struct btf_struct_metas *tab = NULL;
5518 struct btf_id_set *aof;
5519 int i, n, id, ret;
5520
5521 BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
5522 BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
5523
5524 aof = kmalloc(sizeof(*aof), GFP_KERNEL | __GFP_NOWARN);
5525 if (!aof)
5526 return ERR_PTR(-ENOMEM);
5527 aof->cnt = 0;
5528
5529 for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
5530 /* Try to find whether this special type exists in user BTF, and
5531 * if so remember its ID so we can easily find it among members
5532 * of structs that we iterate in the next loop.
5533 */
5534 struct btf_id_set *new_aof;
5535
5536 id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
5537 if (id < 0)
5538 continue;
5539
5540 new_aof = krealloc(aof, offsetof(struct btf_id_set, ids[aof->cnt + 1]),
5541 GFP_KERNEL | __GFP_NOWARN);
5542 if (!new_aof) {
5543 ret = -ENOMEM;
5544 goto free_aof;
5545 }
5546 aof = new_aof;
5547 aof->ids[aof->cnt++] = id;
5548 }
5549
5550 n = btf_nr_types(btf);
5551 for (i = 1; i < n; i++) {
5552 /* Try to find if there are kptrs in user BTF and remember their ID */
5553 struct btf_id_set *new_aof;
5554 struct btf_field_info tmp;
5555 const struct btf_type *t;
5556
5557 t = btf_type_by_id(btf, i);
5558 if (!t) {
5559 ret = -EINVAL;
5560 goto free_aof;
5561 }
5562
5563 ret = btf_find_kptr(btf, t, 0, 0, &tmp);
5564 if (ret != BTF_FIELD_FOUND)
5565 continue;
5566
5567 new_aof = krealloc(aof, offsetof(struct btf_id_set, ids[aof->cnt + 1]),
5568 GFP_KERNEL | __GFP_NOWARN);
5569 if (!new_aof) {
5570 ret = -ENOMEM;
5571 goto free_aof;
5572 }
5573 aof = new_aof;
5574 aof->ids[aof->cnt++] = i;
5575 }
5576
5577 if (!aof->cnt) {
5578 kfree(aof);
5579 return NULL;
5580 }
5581 sort(&aof->ids, aof->cnt, sizeof(aof->ids[0]), btf_id_cmp_func, NULL);
5582
5583 for (i = 1; i < n; i++) {
5584 struct btf_struct_metas *new_tab;
5585 const struct btf_member *member;
5586 struct btf_struct_meta *type;
5587 struct btf_record *record;
5588 const struct btf_type *t;
5589 int j, tab_cnt;
5590
5591 t = btf_type_by_id(btf, i);
5592 if (!__btf_type_is_struct(t))
5593 continue;
5594
5595 cond_resched();
5596
5597 for_each_member(j, t, member) {
5598 if (btf_id_set_contains(aof, member->type))
5599 goto parse;
5600 }
5601 continue;
5602 parse:
5603 tab_cnt = tab ? tab->cnt : 0;
5604 new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),
5605 GFP_KERNEL | __GFP_NOWARN);
5606 if (!new_tab) {
5607 ret = -ENOMEM;
5608 goto free;
5609 }
5610 if (!tab)
5611 new_tab->cnt = 0;
5612 tab = new_tab;
5613
5614 type = &tab->types[tab->cnt];
5615 type->btf_id = i;
5616 record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE |
5617 BPF_RB_ROOT | BPF_RB_NODE | BPF_REFCOUNT |
5618 BPF_KPTR, t->size);
5619 /* The record cannot be unset, treat it as an error if so */
5620 if (IS_ERR_OR_NULL(record)) {
5621 ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
5622 goto free;
5623 }
5624 type->record = record;
5625 tab->cnt++;
5626 }
5627 kfree(aof);
5628 return tab;
5629 free:
5630 btf_struct_metas_free(tab);
5631 free_aof:
5632 kfree(aof);
5633 return ERR_PTR(ret);
5634 }
5635
btf_find_struct_meta(const struct btf * btf,u32 btf_id)5636 struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
5637 {
5638 struct btf_struct_metas *tab;
5639
5640 BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
5641 tab = btf->struct_meta_tab;
5642 if (!tab)
5643 return NULL;
5644 return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
5645 }
5646
btf_check_type_tags(struct btf_verifier_env * env,struct btf * btf,int start_id)5647 static int btf_check_type_tags(struct btf_verifier_env *env,
5648 struct btf *btf, int start_id)
5649 {
5650 int i, n, good_id = start_id - 1;
5651 bool in_tags;
5652
5653 n = btf_nr_types(btf);
5654 for (i = start_id; i < n; i++) {
5655 const struct btf_type *t;
5656 int chain_limit = 32;
5657 u32 cur_id = i;
5658
5659 t = btf_type_by_id(btf, i);
5660 if (!t)
5661 return -EINVAL;
5662 if (!btf_type_is_modifier(t))
5663 continue;
5664
5665 cond_resched();
5666
5667 in_tags = btf_type_is_type_tag(t);
5668 while (btf_type_is_modifier(t)) {
5669 if (!chain_limit--) {
5670 btf_verifier_log(env, "Max chain length or cycle detected");
5671 return -ELOOP;
5672 }
5673 if (btf_type_is_type_tag(t)) {
5674 if (!in_tags) {
5675 btf_verifier_log(env, "Type tags don't precede modifiers");
5676 return -EINVAL;
5677 }
5678 } else if (in_tags) {
5679 in_tags = false;
5680 }
5681 if (cur_id <= good_id)
5682 break;
5683 /* Move to next type */
5684 cur_id = t->type;
5685 t = btf_type_by_id(btf, cur_id);
5686 if (!t)
5687 return -EINVAL;
5688 }
5689 good_id = i;
5690 }
5691 return 0;
5692 }
5693
finalize_log(struct bpf_verifier_log * log,bpfptr_t uattr,u32 uattr_size)5694 static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
5695 {
5696 u32 log_true_size;
5697 int err;
5698
5699 err = bpf_vlog_finalize(log, &log_true_size);
5700
5701 if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
5702 copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
5703 &log_true_size, sizeof(log_true_size)))
5704 err = -EFAULT;
5705
5706 return err;
5707 }
5708
btf_parse(const union bpf_attr * attr,bpfptr_t uattr,u32 uattr_size)5709 static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
5710 {
5711 bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
5712 char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
5713 struct btf_struct_metas *struct_meta_tab;
5714 struct btf_verifier_env *env = NULL;
5715 struct btf *btf = NULL;
5716 u8 *data;
5717 int err, ret;
5718
5719 if (attr->btf_size > BTF_MAX_SIZE)
5720 return ERR_PTR(-E2BIG);
5721
5722 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5723 if (!env)
5724 return ERR_PTR(-ENOMEM);
5725
5726 /* user could have requested verbose verifier output
5727 * and supplied buffer to store the verification trace
5728 */
5729 err = bpf_vlog_init(&env->log, attr->btf_log_level,
5730 log_ubuf, attr->btf_log_size);
5731 if (err)
5732 goto errout_free;
5733
5734 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5735 if (!btf) {
5736 err = -ENOMEM;
5737 goto errout;
5738 }
5739 env->btf = btf;
5740
5741 data = kvmalloc(attr->btf_size, GFP_KERNEL | __GFP_NOWARN);
5742 if (!data) {
5743 err = -ENOMEM;
5744 goto errout;
5745 }
5746
5747 btf->data = data;
5748 btf->data_size = attr->btf_size;
5749
5750 if (copy_from_bpfptr(data, btf_data, attr->btf_size)) {
5751 err = -EFAULT;
5752 goto errout;
5753 }
5754
5755 err = btf_parse_hdr(env);
5756 if (err)
5757 goto errout;
5758
5759 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5760
5761 err = btf_parse_str_sec(env);
5762 if (err)
5763 goto errout;
5764
5765 err = btf_parse_type_sec(env);
5766 if (err)
5767 goto errout;
5768
5769 err = btf_check_type_tags(env, btf, 1);
5770 if (err)
5771 goto errout;
5772
5773 struct_meta_tab = btf_parse_struct_metas(&env->log, btf);
5774 if (IS_ERR(struct_meta_tab)) {
5775 err = PTR_ERR(struct_meta_tab);
5776 goto errout;
5777 }
5778 btf->struct_meta_tab = struct_meta_tab;
5779
5780 if (struct_meta_tab) {
5781 int i;
5782
5783 for (i = 0; i < struct_meta_tab->cnt; i++) {
5784 err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
5785 if (err < 0)
5786 goto errout_meta;
5787 }
5788 }
5789
5790 err = finalize_log(&env->log, uattr, uattr_size);
5791 if (err)
5792 goto errout_free;
5793
5794 btf_verifier_env_free(env);
5795 refcount_set(&btf->refcnt, 1);
5796 return btf;
5797
5798 errout_meta:
5799 btf_free_struct_meta_tab(btf);
5800 errout:
5801 /* overwrite err with -ENOSPC or -EFAULT */
5802 ret = finalize_log(&env->log, uattr, uattr_size);
5803 if (ret)
5804 err = ret;
5805 errout_free:
5806 btf_verifier_env_free(env);
5807 if (btf)
5808 btf_free(btf);
5809 return ERR_PTR(err);
5810 }
5811
5812 extern char __start_BTF[];
5813 extern char __stop_BTF[];
5814 extern struct btf *btf_vmlinux;
5815
5816 #define BPF_MAP_TYPE(_id, _ops)
5817 #define BPF_LINK_TYPE(_id, _name)
5818 static union {
5819 struct bpf_ctx_convert {
5820 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5821 prog_ctx_type _id##_prog; \
5822 kern_ctx_type _id##_kern;
5823 #include <linux/bpf_types.h>
5824 #undef BPF_PROG_TYPE
5825 } *__t;
5826 /* 't' is written once under lock. Read many times. */
5827 const struct btf_type *t;
5828 } bpf_ctx_convert;
5829 enum {
5830 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5831 __ctx_convert##_id,
5832 #include <linux/bpf_types.h>
5833 #undef BPF_PROG_TYPE
5834 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
5835 };
5836 static u8 bpf_ctx_convert_map[] = {
5837 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5838 [_id] = __ctx_convert##_id,
5839 #include <linux/bpf_types.h>
5840 #undef BPF_PROG_TYPE
5841 0, /* avoid empty array */
5842 };
5843 #undef BPF_MAP_TYPE
5844 #undef BPF_LINK_TYPE
5845
find_canonical_prog_ctx_type(enum bpf_prog_type prog_type)5846 static const struct btf_type *find_canonical_prog_ctx_type(enum bpf_prog_type prog_type)
5847 {
5848 const struct btf_type *conv_struct;
5849 const struct btf_member *ctx_type;
5850
5851 conv_struct = bpf_ctx_convert.t;
5852 if (!conv_struct)
5853 return NULL;
5854 /* prog_type is valid bpf program type. No need for bounds check. */
5855 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5856 /* ctx_type is a pointer to prog_ctx_type in vmlinux.
5857 * Like 'struct __sk_buff'
5858 */
5859 return btf_type_by_id(btf_vmlinux, ctx_type->type);
5860 }
5861
find_kern_ctx_type_id(enum bpf_prog_type prog_type)5862 static int find_kern_ctx_type_id(enum bpf_prog_type prog_type)
5863 {
5864 const struct btf_type *conv_struct;
5865 const struct btf_member *ctx_type;
5866
5867 conv_struct = bpf_ctx_convert.t;
5868 if (!conv_struct)
5869 return -EFAULT;
5870 /* prog_type is valid bpf program type. No need for bounds check. */
5871 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5872 /* ctx_type is a pointer to prog_ctx_type in vmlinux.
5873 * Like 'struct sk_buff'
5874 */
5875 return ctx_type->type;
5876 }
5877
btf_is_projection_of(const char * pname,const char * tname)5878 bool btf_is_projection_of(const char *pname, const char *tname)
5879 {
5880 if (strcmp(pname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0)
5881 return true;
5882 if (strcmp(pname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0)
5883 return true;
5884 return false;
5885 }
5886
btf_is_prog_ctx_type(struct bpf_verifier_log * log,const struct btf * btf,const struct btf_type * t,enum bpf_prog_type prog_type,int arg)5887 bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5888 const struct btf_type *t, enum bpf_prog_type prog_type,
5889 int arg)
5890 {
5891 const struct btf_type *ctx_type;
5892 const char *tname, *ctx_tname;
5893
5894 t = btf_type_by_id(btf, t->type);
5895
5896 /* KPROBE programs allow bpf_user_pt_regs_t typedef, which we need to
5897 * check before we skip all the typedef below.
5898 */
5899 if (prog_type == BPF_PROG_TYPE_KPROBE) {
5900 while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
5901 t = btf_type_by_id(btf, t->type);
5902
5903 if (btf_type_is_typedef(t)) {
5904 tname = btf_name_by_offset(btf, t->name_off);
5905 if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
5906 return true;
5907 }
5908 }
5909
5910 while (btf_type_is_modifier(t))
5911 t = btf_type_by_id(btf, t->type);
5912 if (!btf_type_is_struct(t)) {
5913 /* Only pointer to struct is supported for now.
5914 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5915 * is not supported yet.
5916 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5917 */
5918 return false;
5919 }
5920 tname = btf_name_by_offset(btf, t->name_off);
5921 if (!tname) {
5922 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5923 return false;
5924 }
5925
5926 ctx_type = find_canonical_prog_ctx_type(prog_type);
5927 if (!ctx_type) {
5928 bpf_log(log, "btf_vmlinux is malformed\n");
5929 /* should not happen */
5930 return false;
5931 }
5932 again:
5933 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5934 if (!ctx_tname) {
5935 /* should not happen */
5936 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
5937 return false;
5938 }
5939 /* program types without named context types work only with arg:ctx tag */
5940 if (ctx_tname[0] == '\0')
5941 return false;
5942 /* only compare that prog's ctx type name is the same as
5943 * kernel expects. No need to compare field by field.
5944 * It's ok for bpf prog to do:
5945 * struct __sk_buff {};
5946 * int socket_filter_bpf_prog(struct __sk_buff *skb)
5947 * { // no fields of skb are ever used }
5948 */
5949 if (btf_is_projection_of(ctx_tname, tname))
5950 return true;
5951 if (strcmp(ctx_tname, tname)) {
5952 /* bpf_user_pt_regs_t is a typedef, so resolve it to
5953 * underlying struct and check name again
5954 */
5955 if (!btf_type_is_modifier(ctx_type))
5956 return false;
5957 while (btf_type_is_modifier(ctx_type))
5958 ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
5959 goto again;
5960 }
5961 return true;
5962 }
5963
5964 /* forward declarations for arch-specific underlying types of
5965 * bpf_user_pt_regs_t; this avoids the need for arch-specific #ifdef
5966 * compilation guards below for BPF_PROG_TYPE_PERF_EVENT checks, but still
5967 * works correctly with __builtin_types_compatible_p() on respective
5968 * architectures
5969 */
5970 struct user_regs_struct;
5971 struct user_pt_regs;
5972
btf_validate_prog_ctx_type(struct bpf_verifier_log * log,const struct btf * btf,const struct btf_type * t,int arg,enum bpf_prog_type prog_type,enum bpf_attach_type attach_type)5973 static int btf_validate_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5974 const struct btf_type *t, int arg,
5975 enum bpf_prog_type prog_type,
5976 enum bpf_attach_type attach_type)
5977 {
5978 const struct btf_type *ctx_type;
5979 const char *tname, *ctx_tname;
5980
5981 if (!btf_is_ptr(t)) {
5982 bpf_log(log, "arg#%d type isn't a pointer\n", arg);
5983 return -EINVAL;
5984 }
5985 t = btf_type_by_id(btf, t->type);
5986
5987 /* KPROBE and PERF_EVENT programs allow bpf_user_pt_regs_t typedef */
5988 if (prog_type == BPF_PROG_TYPE_KPROBE || prog_type == BPF_PROG_TYPE_PERF_EVENT) {
5989 while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
5990 t = btf_type_by_id(btf, t->type);
5991
5992 if (btf_type_is_typedef(t)) {
5993 tname = btf_name_by_offset(btf, t->name_off);
5994 if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
5995 return 0;
5996 }
5997 }
5998
5999 /* all other program types don't use typedefs for context type */
6000 while (btf_type_is_modifier(t))
6001 t = btf_type_by_id(btf, t->type);
6002
6003 /* `void *ctx __arg_ctx` is always valid */
6004 if (btf_type_is_void(t))
6005 return 0;
6006
6007 tname = btf_name_by_offset(btf, t->name_off);
6008 if (str_is_empty(tname)) {
6009 bpf_log(log, "arg#%d type doesn't have a name\n", arg);
6010 return -EINVAL;
6011 }
6012
6013 /* special cases */
6014 switch (prog_type) {
6015 case BPF_PROG_TYPE_KPROBE:
6016 if (__btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
6017 return 0;
6018 break;
6019 case BPF_PROG_TYPE_PERF_EVENT:
6020 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) &&
6021 __btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
6022 return 0;
6023 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) &&
6024 __btf_type_is_struct(t) && strcmp(tname, "user_pt_regs") == 0)
6025 return 0;
6026 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) &&
6027 __btf_type_is_struct(t) && strcmp(tname, "user_regs_struct") == 0)
6028 return 0;
6029 break;
6030 case BPF_PROG_TYPE_RAW_TRACEPOINT:
6031 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
6032 /* allow u64* as ctx */
6033 if (btf_is_int(t) && t->size == 8)
6034 return 0;
6035 break;
6036 case BPF_PROG_TYPE_TRACING:
6037 switch (attach_type) {
6038 case BPF_TRACE_RAW_TP:
6039 /* tp_btf program is TRACING, so need special case here */
6040 if (__btf_type_is_struct(t) &&
6041 strcmp(tname, "bpf_raw_tracepoint_args") == 0)
6042 return 0;
6043 /* allow u64* as ctx */
6044 if (btf_is_int(t) && t->size == 8)
6045 return 0;
6046 break;
6047 case BPF_TRACE_ITER:
6048 /* allow struct bpf_iter__xxx types only */
6049 if (__btf_type_is_struct(t) &&
6050 strncmp(tname, "bpf_iter__", sizeof("bpf_iter__") - 1) == 0)
6051 return 0;
6052 break;
6053 case BPF_TRACE_FENTRY:
6054 case BPF_TRACE_FEXIT:
6055 case BPF_MODIFY_RETURN:
6056 /* allow u64* as ctx */
6057 if (btf_is_int(t) && t->size == 8)
6058 return 0;
6059 break;
6060 default:
6061 break;
6062 }
6063 break;
6064 case BPF_PROG_TYPE_LSM:
6065 case BPF_PROG_TYPE_STRUCT_OPS:
6066 /* allow u64* as ctx */
6067 if (btf_is_int(t) && t->size == 8)
6068 return 0;
6069 break;
6070 case BPF_PROG_TYPE_TRACEPOINT:
6071 case BPF_PROG_TYPE_SYSCALL:
6072 case BPF_PROG_TYPE_EXT:
6073 return 0; /* anything goes */
6074 default:
6075 break;
6076 }
6077
6078 ctx_type = find_canonical_prog_ctx_type(prog_type);
6079 if (!ctx_type) {
6080 /* should not happen */
6081 bpf_log(log, "btf_vmlinux is malformed\n");
6082 return -EINVAL;
6083 }
6084
6085 /* resolve typedefs and check that underlying structs are matching as well */
6086 while (btf_type_is_modifier(ctx_type))
6087 ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
6088
6089 /* if program type doesn't have distinctly named struct type for
6090 * context, then __arg_ctx argument can only be `void *`, which we
6091 * already checked above
6092 */
6093 if (!__btf_type_is_struct(ctx_type)) {
6094 bpf_log(log, "arg#%d should be void pointer\n", arg);
6095 return -EINVAL;
6096 }
6097
6098 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
6099 if (!__btf_type_is_struct(t) || strcmp(ctx_tname, tname) != 0) {
6100 bpf_log(log, "arg#%d should be `struct %s *`\n", arg, ctx_tname);
6101 return -EINVAL;
6102 }
6103
6104 return 0;
6105 }
6106
btf_translate_to_vmlinux(struct bpf_verifier_log * log,struct btf * btf,const struct btf_type * t,enum bpf_prog_type prog_type,int arg)6107 static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
6108 struct btf *btf,
6109 const struct btf_type *t,
6110 enum bpf_prog_type prog_type,
6111 int arg)
6112 {
6113 if (!btf_is_prog_ctx_type(log, btf, t, prog_type, arg))
6114 return -ENOENT;
6115 return find_kern_ctx_type_id(prog_type);
6116 }
6117
get_kern_ctx_btf_id(struct bpf_verifier_log * log,enum bpf_prog_type prog_type)6118 int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type)
6119 {
6120 const struct btf_member *kctx_member;
6121 const struct btf_type *conv_struct;
6122 const struct btf_type *kctx_type;
6123 u32 kctx_type_id;
6124
6125 conv_struct = bpf_ctx_convert.t;
6126 /* get member for kernel ctx type */
6127 kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
6128 kctx_type_id = kctx_member->type;
6129 kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id);
6130 if (!btf_type_is_struct(kctx_type)) {
6131 bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id);
6132 return -EINVAL;
6133 }
6134
6135 return kctx_type_id;
6136 }
6137
6138 BTF_ID_LIST(bpf_ctx_convert_btf_id)
BTF_ID(struct,bpf_ctx_convert)6139 BTF_ID(struct, bpf_ctx_convert)
6140
6141 static struct btf *btf_parse_base(struct btf_verifier_env *env, const char *name,
6142 void *data, unsigned int data_size)
6143 {
6144 struct btf *btf = NULL;
6145 int err;
6146
6147 if (!IS_ENABLED(CONFIG_DEBUG_INFO_BTF))
6148 return ERR_PTR(-ENOENT);
6149
6150 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
6151 if (!btf) {
6152 err = -ENOMEM;
6153 goto errout;
6154 }
6155 env->btf = btf;
6156
6157 btf->data = data;
6158 btf->data_size = data_size;
6159 btf->kernel_btf = true;
6160 snprintf(btf->name, sizeof(btf->name), "%s", name);
6161
6162 err = btf_parse_hdr(env);
6163 if (err)
6164 goto errout;
6165
6166 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6167
6168 err = btf_parse_str_sec(env);
6169 if (err)
6170 goto errout;
6171
6172 err = btf_check_all_metas(env);
6173 if (err)
6174 goto errout;
6175
6176 err = btf_check_type_tags(env, btf, 1);
6177 if (err)
6178 goto errout;
6179
6180 refcount_set(&btf->refcnt, 1);
6181
6182 return btf;
6183
6184 errout:
6185 if (btf) {
6186 kvfree(btf->types);
6187 kfree(btf);
6188 }
6189 return ERR_PTR(err);
6190 }
6191
btf_parse_vmlinux(void)6192 struct btf *btf_parse_vmlinux(void)
6193 {
6194 struct btf_verifier_env *env = NULL;
6195 struct bpf_verifier_log *log;
6196 struct btf *btf;
6197 int err;
6198
6199 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
6200 if (!env)
6201 return ERR_PTR(-ENOMEM);
6202
6203 log = &env->log;
6204 log->level = BPF_LOG_KERNEL;
6205 btf = btf_parse_base(env, "vmlinux", __start_BTF, __stop_BTF - __start_BTF);
6206 if (IS_ERR(btf))
6207 goto err_out;
6208
6209 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
6210 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
6211 err = btf_alloc_id(btf);
6212 if (err) {
6213 btf_free(btf);
6214 btf = ERR_PTR(err);
6215 }
6216 err_out:
6217 btf_verifier_env_free(env);
6218 return btf;
6219 }
6220
6221 /* If .BTF_ids section was created with distilled base BTF, both base and
6222 * split BTF ids will need to be mapped to actual base/split ids for
6223 * BTF now that it has been relocated.
6224 */
btf_relocate_id(const struct btf * btf,__u32 id)6225 static __u32 btf_relocate_id(const struct btf *btf, __u32 id)
6226 {
6227 if (!btf->base_btf || !btf->base_id_map)
6228 return id;
6229 return btf->base_id_map[id];
6230 }
6231
6232 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6233
btf_parse_module(const char * module_name,const void * data,unsigned int data_size,void * base_data,unsigned int base_data_size)6234 static struct btf *btf_parse_module(const char *module_name, const void *data,
6235 unsigned int data_size, void *base_data,
6236 unsigned int base_data_size)
6237 {
6238 struct btf *btf = NULL, *vmlinux_btf, *base_btf = NULL;
6239 struct btf_verifier_env *env = NULL;
6240 struct bpf_verifier_log *log;
6241 int err = 0;
6242
6243 vmlinux_btf = bpf_get_btf_vmlinux();
6244 if (IS_ERR(vmlinux_btf))
6245 return vmlinux_btf;
6246 if (!vmlinux_btf)
6247 return ERR_PTR(-EINVAL);
6248
6249 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
6250 if (!env)
6251 return ERR_PTR(-ENOMEM);
6252
6253 log = &env->log;
6254 log->level = BPF_LOG_KERNEL;
6255
6256 if (base_data) {
6257 base_btf = btf_parse_base(env, ".BTF.base", base_data, base_data_size);
6258 if (IS_ERR(base_btf)) {
6259 err = PTR_ERR(base_btf);
6260 goto errout;
6261 }
6262 } else {
6263 base_btf = vmlinux_btf;
6264 }
6265
6266 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
6267 if (!btf) {
6268 err = -ENOMEM;
6269 goto errout;
6270 }
6271 env->btf = btf;
6272
6273 btf->base_btf = base_btf;
6274 btf->start_id = base_btf->nr_types;
6275 btf->start_str_off = base_btf->hdr.str_len;
6276 btf->kernel_btf = true;
6277 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
6278
6279 btf->data = kvmemdup(data, data_size, GFP_KERNEL | __GFP_NOWARN);
6280 if (!btf->data) {
6281 err = -ENOMEM;
6282 goto errout;
6283 }
6284 btf->data_size = data_size;
6285
6286 err = btf_parse_hdr(env);
6287 if (err)
6288 goto errout;
6289
6290 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6291
6292 err = btf_parse_str_sec(env);
6293 if (err)
6294 goto errout;
6295
6296 err = btf_check_all_metas(env);
6297 if (err)
6298 goto errout;
6299
6300 err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
6301 if (err)
6302 goto errout;
6303
6304 if (base_btf != vmlinux_btf) {
6305 err = btf_relocate(btf, vmlinux_btf, &btf->base_id_map);
6306 if (err)
6307 goto errout;
6308 btf_free(base_btf);
6309 base_btf = vmlinux_btf;
6310 }
6311
6312 btf_verifier_env_free(env);
6313 refcount_set(&btf->refcnt, 1);
6314 return btf;
6315
6316 errout:
6317 btf_verifier_env_free(env);
6318 if (!IS_ERR(base_btf) && base_btf != vmlinux_btf)
6319 btf_free(base_btf);
6320 if (btf) {
6321 kvfree(btf->data);
6322 kvfree(btf->types);
6323 kfree(btf);
6324 }
6325 return ERR_PTR(err);
6326 }
6327
6328 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6329
bpf_prog_get_target_btf(const struct bpf_prog * prog)6330 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
6331 {
6332 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6333
6334 if (tgt_prog)
6335 return tgt_prog->aux->btf;
6336 else
6337 return prog->aux->attach_btf;
6338 }
6339
is_int_ptr(struct btf * btf,const struct btf_type * t)6340 static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
6341 {
6342 /* skip modifiers */
6343 t = btf_type_skip_modifiers(btf, t->type, NULL);
6344
6345 return btf_type_is_int(t);
6346 }
6347
get_ctx_arg_idx(struct btf * btf,const struct btf_type * func_proto,int off)6348 static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
6349 int off)
6350 {
6351 const struct btf_param *args;
6352 const struct btf_type *t;
6353 u32 offset = 0, nr_args;
6354 int i;
6355
6356 if (!func_proto)
6357 return off / 8;
6358
6359 nr_args = btf_type_vlen(func_proto);
6360 args = (const struct btf_param *)(func_proto + 1);
6361 for (i = 0; i < nr_args; i++) {
6362 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6363 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6364 if (off < offset)
6365 return i;
6366 }
6367
6368 t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
6369 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6370 if (off < offset)
6371 return nr_args;
6372
6373 return nr_args + 1;
6374 }
6375
prog_args_trusted(const struct bpf_prog * prog)6376 static bool prog_args_trusted(const struct bpf_prog *prog)
6377 {
6378 enum bpf_attach_type atype = prog->expected_attach_type;
6379
6380 switch (prog->type) {
6381 case BPF_PROG_TYPE_TRACING:
6382 return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER;
6383 case BPF_PROG_TYPE_LSM:
6384 return bpf_lsm_is_trusted(prog);
6385 case BPF_PROG_TYPE_STRUCT_OPS:
6386 return true;
6387 default:
6388 return false;
6389 }
6390 }
6391
btf_ctx_arg_offset(const struct btf * btf,const struct btf_type * func_proto,u32 arg_no)6392 int btf_ctx_arg_offset(const struct btf *btf, const struct btf_type *func_proto,
6393 u32 arg_no)
6394 {
6395 const struct btf_param *args;
6396 const struct btf_type *t;
6397 int off = 0, i;
6398 u32 sz;
6399
6400 args = btf_params(func_proto);
6401 for (i = 0; i < arg_no; i++) {
6402 t = btf_type_by_id(btf, args[i].type);
6403 t = btf_resolve_size(btf, t, &sz);
6404 if (IS_ERR(t))
6405 return PTR_ERR(t);
6406 off += roundup(sz, 8);
6407 }
6408
6409 return off;
6410 }
6411
btf_ctx_access(int off,int size,enum bpf_access_type type,const struct bpf_prog * prog,struct bpf_insn_access_aux * info)6412 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
6413 const struct bpf_prog *prog,
6414 struct bpf_insn_access_aux *info)
6415 {
6416 const struct btf_type *t = prog->aux->attach_func_proto;
6417 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6418 struct btf *btf = bpf_prog_get_target_btf(prog);
6419 const char *tname = prog->aux->attach_func_name;
6420 struct bpf_verifier_log *log = info->log;
6421 const struct btf_param *args;
6422 const char *tag_value;
6423 u32 nr_args, arg;
6424 int i, ret;
6425
6426 if (off % 8) {
6427 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
6428 tname, off);
6429 return false;
6430 }
6431 arg = get_ctx_arg_idx(btf, t, off);
6432 args = (const struct btf_param *)(t + 1);
6433 /* if (t == NULL) Fall back to default BPF prog with
6434 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
6435 */
6436 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
6437 if (prog->aux->attach_btf_trace) {
6438 /* skip first 'void *__data' argument in btf_trace_##name typedef */
6439 args++;
6440 nr_args--;
6441 }
6442
6443 if (arg > nr_args) {
6444 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6445 tname, arg + 1);
6446 return false;
6447 }
6448
6449 if (arg == nr_args) {
6450 switch (prog->expected_attach_type) {
6451 case BPF_LSM_MAC:
6452 /* mark we are accessing the return value */
6453 info->is_retval = true;
6454 fallthrough;
6455 case BPF_LSM_CGROUP:
6456 case BPF_TRACE_FEXIT:
6457 /* When LSM programs are attached to void LSM hooks
6458 * they use FEXIT trampolines and when attached to
6459 * int LSM hooks, they use MODIFY_RETURN trampolines.
6460 *
6461 * While the LSM programs are BPF_MODIFY_RETURN-like
6462 * the check:
6463 *
6464 * if (ret_type != 'int')
6465 * return -EINVAL;
6466 *
6467 * is _not_ done here. This is still safe as LSM hooks
6468 * have only void and int return types.
6469 */
6470 if (!t)
6471 return true;
6472 t = btf_type_by_id(btf, t->type);
6473 break;
6474 case BPF_MODIFY_RETURN:
6475 /* For now the BPF_MODIFY_RETURN can only be attached to
6476 * functions that return an int.
6477 */
6478 if (!t)
6479 return false;
6480
6481 t = btf_type_skip_modifiers(btf, t->type, NULL);
6482 if (!btf_type_is_small_int(t)) {
6483 bpf_log(log,
6484 "ret type %s not allowed for fmod_ret\n",
6485 btf_type_str(t));
6486 return false;
6487 }
6488 break;
6489 default:
6490 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6491 tname, arg + 1);
6492 return false;
6493 }
6494 } else {
6495 if (!t)
6496 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
6497 return true;
6498 t = btf_type_by_id(btf, args[arg].type);
6499 }
6500
6501 /* skip modifiers */
6502 while (btf_type_is_modifier(t))
6503 t = btf_type_by_id(btf, t->type);
6504 if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6505 /* accessing a scalar */
6506 return true;
6507 if (!btf_type_is_ptr(t)) {
6508 bpf_log(log,
6509 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
6510 tname, arg,
6511 __btf_name_by_offset(btf, t->name_off),
6512 btf_type_str(t));
6513 return false;
6514 }
6515
6516 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
6517 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6518 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6519 u32 type, flag;
6520
6521 type = base_type(ctx_arg_info->reg_type);
6522 flag = type_flag(ctx_arg_info->reg_type);
6523 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
6524 (flag & PTR_MAYBE_NULL)) {
6525 info->reg_type = ctx_arg_info->reg_type;
6526 return true;
6527 }
6528 }
6529
6530 if (t->type == 0)
6531 /* This is a pointer to void.
6532 * It is the same as scalar from the verifier safety pov.
6533 * No further pointer walking is allowed.
6534 */
6535 return true;
6536
6537 if (is_int_ptr(btf, t))
6538 return true;
6539
6540 /* this is a pointer to another type */
6541 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6542 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6543
6544 if (ctx_arg_info->offset == off) {
6545 if (!ctx_arg_info->btf_id) {
6546 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
6547 return false;
6548 }
6549
6550 info->reg_type = ctx_arg_info->reg_type;
6551 info->btf = ctx_arg_info->btf ? : btf_vmlinux;
6552 info->btf_id = ctx_arg_info->btf_id;
6553 return true;
6554 }
6555 }
6556
6557 info->reg_type = PTR_TO_BTF_ID;
6558 if (prog_args_trusted(prog))
6559 info->reg_type |= PTR_TRUSTED;
6560
6561 if (btf_param_match_suffix(btf, &args[arg], "__nullable"))
6562 info->reg_type |= PTR_MAYBE_NULL;
6563
6564 if (tgt_prog) {
6565 enum bpf_prog_type tgt_type;
6566
6567 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
6568 tgt_type = tgt_prog->aux->saved_dst_prog_type;
6569 else
6570 tgt_type = tgt_prog->type;
6571
6572 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
6573 if (ret > 0) {
6574 info->btf = btf_vmlinux;
6575 info->btf_id = ret;
6576 return true;
6577 } else {
6578 return false;
6579 }
6580 }
6581
6582 info->btf = btf;
6583 info->btf_id = t->type;
6584 t = btf_type_by_id(btf, t->type);
6585
6586 if (btf_type_is_type_tag(t)) {
6587 tag_value = __btf_name_by_offset(btf, t->name_off);
6588 if (strcmp(tag_value, "user") == 0)
6589 info->reg_type |= MEM_USER;
6590 if (strcmp(tag_value, "percpu") == 0)
6591 info->reg_type |= MEM_PERCPU;
6592 }
6593
6594 /* skip modifiers */
6595 while (btf_type_is_modifier(t)) {
6596 info->btf_id = t->type;
6597 t = btf_type_by_id(btf, t->type);
6598 }
6599 if (!btf_type_is_struct(t)) {
6600 bpf_log(log,
6601 "func '%s' arg%d type %s is not a struct\n",
6602 tname, arg, btf_type_str(t));
6603 return false;
6604 }
6605 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
6606 tname, arg, info->btf_id, btf_type_str(t),
6607 __btf_name_by_offset(btf, t->name_off));
6608 return true;
6609 }
6610 EXPORT_SYMBOL_GPL(btf_ctx_access);
6611
6612 enum bpf_struct_walk_result {
6613 /* < 0 error */
6614 WALK_SCALAR = 0,
6615 WALK_PTR,
6616 WALK_STRUCT,
6617 };
6618
btf_struct_walk(struct bpf_verifier_log * log,const struct btf * btf,const struct btf_type * t,int off,int size,u32 * next_btf_id,enum bpf_type_flag * flag,const char ** field_name)6619 static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
6620 const struct btf_type *t, int off, int size,
6621 u32 *next_btf_id, enum bpf_type_flag *flag,
6622 const char **field_name)
6623 {
6624 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
6625 const struct btf_type *mtype, *elem_type = NULL;
6626 const struct btf_member *member;
6627 const char *tname, *mname, *tag_value;
6628 u32 vlen, elem_id, mid;
6629
6630 again:
6631 if (btf_type_is_modifier(t))
6632 t = btf_type_skip_modifiers(btf, t->type, NULL);
6633 tname = __btf_name_by_offset(btf, t->name_off);
6634 if (!btf_type_is_struct(t)) {
6635 bpf_log(log, "Type '%s' is not a struct\n", tname);
6636 return -EINVAL;
6637 }
6638
6639 vlen = btf_type_vlen(t);
6640 if (BTF_INFO_KIND(t->info) == BTF_KIND_UNION && vlen != 1 && !(*flag & PTR_UNTRUSTED))
6641 /*
6642 * walking unions yields untrusted pointers
6643 * with exception of __bpf_md_ptr and other
6644 * unions with a single member
6645 */
6646 *flag |= PTR_UNTRUSTED;
6647
6648 if (off + size > t->size) {
6649 /* If the last element is a variable size array, we may
6650 * need to relax the rule.
6651 */
6652 struct btf_array *array_elem;
6653
6654 if (vlen == 0)
6655 goto error;
6656
6657 member = btf_type_member(t) + vlen - 1;
6658 mtype = btf_type_skip_modifiers(btf, member->type,
6659 NULL);
6660 if (!btf_type_is_array(mtype))
6661 goto error;
6662
6663 array_elem = (struct btf_array *)(mtype + 1);
6664 if (array_elem->nelems != 0)
6665 goto error;
6666
6667 moff = __btf_member_bit_offset(t, member) / 8;
6668 if (off < moff)
6669 goto error;
6670
6671 /* allow structure and integer */
6672 t = btf_type_skip_modifiers(btf, array_elem->type,
6673 NULL);
6674
6675 if (btf_type_is_int(t))
6676 return WALK_SCALAR;
6677
6678 if (!btf_type_is_struct(t))
6679 goto error;
6680
6681 off = (off - moff) % t->size;
6682 goto again;
6683
6684 error:
6685 bpf_log(log, "access beyond struct %s at off %u size %u\n",
6686 tname, off, size);
6687 return -EACCES;
6688 }
6689
6690 for_each_member(i, t, member) {
6691 /* offset of the field in bytes */
6692 moff = __btf_member_bit_offset(t, member) / 8;
6693 if (off + size <= moff)
6694 /* won't find anything, field is already too far */
6695 break;
6696
6697 if (__btf_member_bitfield_size(t, member)) {
6698 u32 end_bit = __btf_member_bit_offset(t, member) +
6699 __btf_member_bitfield_size(t, member);
6700
6701 /* off <= moff instead of off == moff because clang
6702 * does not generate a BTF member for anonymous
6703 * bitfield like the ":16" here:
6704 * struct {
6705 * int :16;
6706 * int x:8;
6707 * };
6708 */
6709 if (off <= moff &&
6710 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
6711 return WALK_SCALAR;
6712
6713 /* off may be accessing a following member
6714 *
6715 * or
6716 *
6717 * Doing partial access at either end of this
6718 * bitfield. Continue on this case also to
6719 * treat it as not accessing this bitfield
6720 * and eventually error out as field not
6721 * found to keep it simple.
6722 * It could be relaxed if there was a legit
6723 * partial access case later.
6724 */
6725 continue;
6726 }
6727
6728 /* In case of "off" is pointing to holes of a struct */
6729 if (off < moff)
6730 break;
6731
6732 /* type of the field */
6733 mid = member->type;
6734 mtype = btf_type_by_id(btf, member->type);
6735 mname = __btf_name_by_offset(btf, member->name_off);
6736
6737 mtype = __btf_resolve_size(btf, mtype, &msize,
6738 &elem_type, &elem_id, &total_nelems,
6739 &mid);
6740 if (IS_ERR(mtype)) {
6741 bpf_log(log, "field %s doesn't have size\n", mname);
6742 return -EFAULT;
6743 }
6744
6745 mtrue_end = moff + msize;
6746 if (off >= mtrue_end)
6747 /* no overlap with member, keep iterating */
6748 continue;
6749
6750 if (btf_type_is_array(mtype)) {
6751 u32 elem_idx;
6752
6753 /* __btf_resolve_size() above helps to
6754 * linearize a multi-dimensional array.
6755 *
6756 * The logic here is treating an array
6757 * in a struct as the following way:
6758 *
6759 * struct outer {
6760 * struct inner array[2][2];
6761 * };
6762 *
6763 * looks like:
6764 *
6765 * struct outer {
6766 * struct inner array_elem0;
6767 * struct inner array_elem1;
6768 * struct inner array_elem2;
6769 * struct inner array_elem3;
6770 * };
6771 *
6772 * When accessing outer->array[1][0], it moves
6773 * moff to "array_elem2", set mtype to
6774 * "struct inner", and msize also becomes
6775 * sizeof(struct inner). Then most of the
6776 * remaining logic will fall through without
6777 * caring the current member is an array or
6778 * not.
6779 *
6780 * Unlike mtype/msize/moff, mtrue_end does not
6781 * change. The naming difference ("_true") tells
6782 * that it is not always corresponding to
6783 * the current mtype/msize/moff.
6784 * It is the true end of the current
6785 * member (i.e. array in this case). That
6786 * will allow an int array to be accessed like
6787 * a scratch space,
6788 * i.e. allow access beyond the size of
6789 * the array's element as long as it is
6790 * within the mtrue_end boundary.
6791 */
6792
6793 /* skip empty array */
6794 if (moff == mtrue_end)
6795 continue;
6796
6797 msize /= total_nelems;
6798 elem_idx = (off - moff) / msize;
6799 moff += elem_idx * msize;
6800 mtype = elem_type;
6801 mid = elem_id;
6802 }
6803
6804 /* the 'off' we're looking for is either equal to start
6805 * of this field or inside of this struct
6806 */
6807 if (btf_type_is_struct(mtype)) {
6808 /* our field must be inside that union or struct */
6809 t = mtype;
6810
6811 /* return if the offset matches the member offset */
6812 if (off == moff) {
6813 *next_btf_id = mid;
6814 return WALK_STRUCT;
6815 }
6816
6817 /* adjust offset we're looking for */
6818 off -= moff;
6819 goto again;
6820 }
6821
6822 if (btf_type_is_ptr(mtype)) {
6823 const struct btf_type *stype, *t;
6824 enum bpf_type_flag tmp_flag = 0;
6825 u32 id;
6826
6827 if (msize != size || off != moff) {
6828 bpf_log(log,
6829 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
6830 mname, moff, tname, off, size);
6831 return -EACCES;
6832 }
6833
6834 /* check type tag */
6835 t = btf_type_by_id(btf, mtype->type);
6836 if (btf_type_is_type_tag(t)) {
6837 tag_value = __btf_name_by_offset(btf, t->name_off);
6838 /* check __user tag */
6839 if (strcmp(tag_value, "user") == 0)
6840 tmp_flag = MEM_USER;
6841 /* check __percpu tag */
6842 if (strcmp(tag_value, "percpu") == 0)
6843 tmp_flag = MEM_PERCPU;
6844 /* check __rcu tag */
6845 if (strcmp(tag_value, "rcu") == 0)
6846 tmp_flag = MEM_RCU;
6847 }
6848
6849 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
6850 if (btf_type_is_struct(stype)) {
6851 *next_btf_id = id;
6852 *flag |= tmp_flag;
6853 if (field_name)
6854 *field_name = mname;
6855 return WALK_PTR;
6856 }
6857 }
6858
6859 /* Allow more flexible access within an int as long as
6860 * it is within mtrue_end.
6861 * Since mtrue_end could be the end of an array,
6862 * that also allows using an array of int as a scratch
6863 * space. e.g. skb->cb[].
6864 */
6865 if (off + size > mtrue_end && !(*flag & PTR_UNTRUSTED)) {
6866 bpf_log(log,
6867 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
6868 mname, mtrue_end, tname, off, size);
6869 return -EACCES;
6870 }
6871
6872 return WALK_SCALAR;
6873 }
6874 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
6875 return -EINVAL;
6876 }
6877
btf_struct_access(struct bpf_verifier_log * log,const struct bpf_reg_state * reg,int off,int size,enum bpf_access_type atype __maybe_unused,u32 * next_btf_id,enum bpf_type_flag * flag,const char ** field_name)6878 int btf_struct_access(struct bpf_verifier_log *log,
6879 const struct bpf_reg_state *reg,
6880 int off, int size, enum bpf_access_type atype __maybe_unused,
6881 u32 *next_btf_id, enum bpf_type_flag *flag,
6882 const char **field_name)
6883 {
6884 const struct btf *btf = reg->btf;
6885 enum bpf_type_flag tmp_flag = 0;
6886 const struct btf_type *t;
6887 u32 id = reg->btf_id;
6888 int err;
6889
6890 while (type_is_alloc(reg->type)) {
6891 struct btf_struct_meta *meta;
6892 struct btf_record *rec;
6893 int i;
6894
6895 meta = btf_find_struct_meta(btf, id);
6896 if (!meta)
6897 break;
6898 rec = meta->record;
6899 for (i = 0; i < rec->cnt; i++) {
6900 struct btf_field *field = &rec->fields[i];
6901 u32 offset = field->offset;
6902 if (off < offset + field->size && offset < off + size) {
6903 bpf_log(log,
6904 "direct access to %s is disallowed\n",
6905 btf_field_type_name(field->type));
6906 return -EACCES;
6907 }
6908 }
6909 break;
6910 }
6911
6912 t = btf_type_by_id(btf, id);
6913 do {
6914 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag, field_name);
6915
6916 switch (err) {
6917 case WALK_PTR:
6918 /* For local types, the destination register cannot
6919 * become a pointer again.
6920 */
6921 if (type_is_alloc(reg->type))
6922 return SCALAR_VALUE;
6923 /* If we found the pointer or scalar on t+off,
6924 * we're done.
6925 */
6926 *next_btf_id = id;
6927 *flag = tmp_flag;
6928 return PTR_TO_BTF_ID;
6929 case WALK_SCALAR:
6930 return SCALAR_VALUE;
6931 case WALK_STRUCT:
6932 /* We found nested struct, so continue the search
6933 * by diving in it. At this point the offset is
6934 * aligned with the new type, so set it to 0.
6935 */
6936 t = btf_type_by_id(btf, id);
6937 off = 0;
6938 break;
6939 default:
6940 /* It's either error or unknown return value..
6941 * scream and leave.
6942 */
6943 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
6944 return -EINVAL;
6945 return err;
6946 }
6947 } while (t);
6948
6949 return -EINVAL;
6950 }
6951
6952 /* Check that two BTF types, each specified as an BTF object + id, are exactly
6953 * the same. Trivial ID check is not enough due to module BTFs, because we can
6954 * end up with two different module BTFs, but IDs point to the common type in
6955 * vmlinux BTF.
6956 */
btf_types_are_same(const struct btf * btf1,u32 id1,const struct btf * btf2,u32 id2)6957 bool btf_types_are_same(const struct btf *btf1, u32 id1,
6958 const struct btf *btf2, u32 id2)
6959 {
6960 if (id1 != id2)
6961 return false;
6962 if (btf1 == btf2)
6963 return true;
6964 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
6965 }
6966
btf_struct_ids_match(struct bpf_verifier_log * log,const struct btf * btf,u32 id,int off,const struct btf * need_btf,u32 need_type_id,bool strict)6967 bool btf_struct_ids_match(struct bpf_verifier_log *log,
6968 const struct btf *btf, u32 id, int off,
6969 const struct btf *need_btf, u32 need_type_id,
6970 bool strict)
6971 {
6972 const struct btf_type *type;
6973 enum bpf_type_flag flag = 0;
6974 int err;
6975
6976 /* Are we already done? */
6977 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
6978 return true;
6979 /* In case of strict type match, we do not walk struct, the top level
6980 * type match must succeed. When strict is true, off should have already
6981 * been 0.
6982 */
6983 if (strict)
6984 return false;
6985 again:
6986 type = btf_type_by_id(btf, id);
6987 if (!type)
6988 return false;
6989 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag, NULL);
6990 if (err != WALK_STRUCT)
6991 return false;
6992
6993 /* We found nested struct object. If it matches
6994 * the requested ID, we're done. Otherwise let's
6995 * continue the search with offset 0 in the new
6996 * type.
6997 */
6998 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
6999 off = 0;
7000 goto again;
7001 }
7002
7003 return true;
7004 }
7005
__get_type_size(struct btf * btf,u32 btf_id,const struct btf_type ** ret_type)7006 static int __get_type_size(struct btf *btf, u32 btf_id,
7007 const struct btf_type **ret_type)
7008 {
7009 const struct btf_type *t;
7010
7011 *ret_type = btf_type_by_id(btf, 0);
7012 if (!btf_id)
7013 /* void */
7014 return 0;
7015 t = btf_type_by_id(btf, btf_id);
7016 while (t && btf_type_is_modifier(t))
7017 t = btf_type_by_id(btf, t->type);
7018 if (!t)
7019 return -EINVAL;
7020 *ret_type = t;
7021 if (btf_type_is_ptr(t))
7022 /* kernel size of pointer. Not BPF's size of pointer*/
7023 return sizeof(void *);
7024 if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
7025 return t->size;
7026 return -EINVAL;
7027 }
7028
__get_type_fmodel_flags(const struct btf_type * t)7029 static u8 __get_type_fmodel_flags(const struct btf_type *t)
7030 {
7031 u8 flags = 0;
7032
7033 if (__btf_type_is_struct(t))
7034 flags |= BTF_FMODEL_STRUCT_ARG;
7035 if (btf_type_is_signed_int(t))
7036 flags |= BTF_FMODEL_SIGNED_ARG;
7037
7038 return flags;
7039 }
7040
btf_distill_func_proto(struct bpf_verifier_log * log,struct btf * btf,const struct btf_type * func,const char * tname,struct btf_func_model * m)7041 int btf_distill_func_proto(struct bpf_verifier_log *log,
7042 struct btf *btf,
7043 const struct btf_type *func,
7044 const char *tname,
7045 struct btf_func_model *m)
7046 {
7047 const struct btf_param *args;
7048 const struct btf_type *t;
7049 u32 i, nargs;
7050 int ret;
7051
7052 if (!func) {
7053 /* BTF function prototype doesn't match the verifier types.
7054 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
7055 */
7056 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
7057 m->arg_size[i] = 8;
7058 m->arg_flags[i] = 0;
7059 }
7060 m->ret_size = 8;
7061 m->ret_flags = 0;
7062 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
7063 return 0;
7064 }
7065 args = (const struct btf_param *)(func + 1);
7066 nargs = btf_type_vlen(func);
7067 if (nargs > MAX_BPF_FUNC_ARGS) {
7068 bpf_log(log,
7069 "The function %s has %d arguments. Too many.\n",
7070 tname, nargs);
7071 return -EINVAL;
7072 }
7073 ret = __get_type_size(btf, func->type, &t);
7074 if (ret < 0 || __btf_type_is_struct(t)) {
7075 bpf_log(log,
7076 "The function %s return type %s is unsupported.\n",
7077 tname, btf_type_str(t));
7078 return -EINVAL;
7079 }
7080 m->ret_size = ret;
7081 m->ret_flags = __get_type_fmodel_flags(t);
7082
7083 for (i = 0; i < nargs; i++) {
7084 if (i == nargs - 1 && args[i].type == 0) {
7085 bpf_log(log,
7086 "The function %s with variable args is unsupported.\n",
7087 tname);
7088 return -EINVAL;
7089 }
7090 ret = __get_type_size(btf, args[i].type, &t);
7091
7092 /* No support of struct argument size greater than 16 bytes */
7093 if (ret < 0 || ret > 16) {
7094 bpf_log(log,
7095 "The function %s arg%d type %s is unsupported.\n",
7096 tname, i, btf_type_str(t));
7097 return -EINVAL;
7098 }
7099 if (ret == 0) {
7100 bpf_log(log,
7101 "The function %s has malformed void argument.\n",
7102 tname);
7103 return -EINVAL;
7104 }
7105 m->arg_size[i] = ret;
7106 m->arg_flags[i] = __get_type_fmodel_flags(t);
7107 }
7108 m->nr_args = nargs;
7109 return 0;
7110 }
7111
7112 /* Compare BTFs of two functions assuming only scalars and pointers to context.
7113 * t1 points to BTF_KIND_FUNC in btf1
7114 * t2 points to BTF_KIND_FUNC in btf2
7115 * Returns:
7116 * EINVAL - function prototype mismatch
7117 * EFAULT - verifier bug
7118 * 0 - 99% match. The last 1% is validated by the verifier.
7119 */
btf_check_func_type_match(struct bpf_verifier_log * log,struct btf * btf1,const struct btf_type * t1,struct btf * btf2,const struct btf_type * t2)7120 static int btf_check_func_type_match(struct bpf_verifier_log *log,
7121 struct btf *btf1, const struct btf_type *t1,
7122 struct btf *btf2, const struct btf_type *t2)
7123 {
7124 const struct btf_param *args1, *args2;
7125 const char *fn1, *fn2, *s1, *s2;
7126 u32 nargs1, nargs2, i;
7127
7128 fn1 = btf_name_by_offset(btf1, t1->name_off);
7129 fn2 = btf_name_by_offset(btf2, t2->name_off);
7130
7131 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
7132 bpf_log(log, "%s() is not a global function\n", fn1);
7133 return -EINVAL;
7134 }
7135 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
7136 bpf_log(log, "%s() is not a global function\n", fn2);
7137 return -EINVAL;
7138 }
7139
7140 t1 = btf_type_by_id(btf1, t1->type);
7141 if (!t1 || !btf_type_is_func_proto(t1))
7142 return -EFAULT;
7143 t2 = btf_type_by_id(btf2, t2->type);
7144 if (!t2 || !btf_type_is_func_proto(t2))
7145 return -EFAULT;
7146
7147 args1 = (const struct btf_param *)(t1 + 1);
7148 nargs1 = btf_type_vlen(t1);
7149 args2 = (const struct btf_param *)(t2 + 1);
7150 nargs2 = btf_type_vlen(t2);
7151
7152 if (nargs1 != nargs2) {
7153 bpf_log(log, "%s() has %d args while %s() has %d args\n",
7154 fn1, nargs1, fn2, nargs2);
7155 return -EINVAL;
7156 }
7157
7158 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
7159 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
7160 if (t1->info != t2->info) {
7161 bpf_log(log,
7162 "Return type %s of %s() doesn't match type %s of %s()\n",
7163 btf_type_str(t1), fn1,
7164 btf_type_str(t2), fn2);
7165 return -EINVAL;
7166 }
7167
7168 for (i = 0; i < nargs1; i++) {
7169 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
7170 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
7171
7172 if (t1->info != t2->info) {
7173 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
7174 i, fn1, btf_type_str(t1),
7175 fn2, btf_type_str(t2));
7176 return -EINVAL;
7177 }
7178 if (btf_type_has_size(t1) && t1->size != t2->size) {
7179 bpf_log(log,
7180 "arg%d in %s() has size %d while %s() has %d\n",
7181 i, fn1, t1->size,
7182 fn2, t2->size);
7183 return -EINVAL;
7184 }
7185
7186 /* global functions are validated with scalars and pointers
7187 * to context only. And only global functions can be replaced.
7188 * Hence type check only those types.
7189 */
7190 if (btf_type_is_int(t1) || btf_is_any_enum(t1))
7191 continue;
7192 if (!btf_type_is_ptr(t1)) {
7193 bpf_log(log,
7194 "arg%d in %s() has unrecognized type\n",
7195 i, fn1);
7196 return -EINVAL;
7197 }
7198 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
7199 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
7200 if (!btf_type_is_struct(t1)) {
7201 bpf_log(log,
7202 "arg%d in %s() is not a pointer to context\n",
7203 i, fn1);
7204 return -EINVAL;
7205 }
7206 if (!btf_type_is_struct(t2)) {
7207 bpf_log(log,
7208 "arg%d in %s() is not a pointer to context\n",
7209 i, fn2);
7210 return -EINVAL;
7211 }
7212 /* This is an optional check to make program writing easier.
7213 * Compare names of structs and report an error to the user.
7214 * btf_prepare_func_args() already checked that t2 struct
7215 * is a context type. btf_prepare_func_args() will check
7216 * later that t1 struct is a context type as well.
7217 */
7218 s1 = btf_name_by_offset(btf1, t1->name_off);
7219 s2 = btf_name_by_offset(btf2, t2->name_off);
7220 if (strcmp(s1, s2)) {
7221 bpf_log(log,
7222 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
7223 i, fn1, s1, fn2, s2);
7224 return -EINVAL;
7225 }
7226 }
7227 return 0;
7228 }
7229
7230 /* Compare BTFs of given program with BTF of target program */
btf_check_type_match(struct bpf_verifier_log * log,const struct bpf_prog * prog,struct btf * btf2,const struct btf_type * t2)7231 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
7232 struct btf *btf2, const struct btf_type *t2)
7233 {
7234 struct btf *btf1 = prog->aux->btf;
7235 const struct btf_type *t1;
7236 u32 btf_id = 0;
7237
7238 if (!prog->aux->func_info) {
7239 bpf_log(log, "Program extension requires BTF\n");
7240 return -EINVAL;
7241 }
7242
7243 btf_id = prog->aux->func_info[0].type_id;
7244 if (!btf_id)
7245 return -EFAULT;
7246
7247 t1 = btf_type_by_id(btf1, btf_id);
7248 if (!t1 || !btf_type_is_func(t1))
7249 return -EFAULT;
7250
7251 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
7252 }
7253
btf_is_dynptr_ptr(const struct btf * btf,const struct btf_type * t)7254 static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t)
7255 {
7256 const char *name;
7257
7258 t = btf_type_by_id(btf, t->type); /* skip PTR */
7259
7260 while (btf_type_is_modifier(t))
7261 t = btf_type_by_id(btf, t->type);
7262
7263 /* allow either struct or struct forward declaration */
7264 if (btf_type_is_struct(t) ||
7265 (btf_type_is_fwd(t) && btf_type_kflag(t) == 0)) {
7266 name = btf_str_by_offset(btf, t->name_off);
7267 return name && strcmp(name, "bpf_dynptr") == 0;
7268 }
7269
7270 return false;
7271 }
7272
7273 struct bpf_cand_cache {
7274 const char *name;
7275 u32 name_len;
7276 u16 kind;
7277 u16 cnt;
7278 struct {
7279 const struct btf *btf;
7280 u32 id;
7281 } cands[];
7282 };
7283
7284 static DEFINE_MUTEX(cand_cache_mutex);
7285
7286 static struct bpf_cand_cache *
7287 bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id);
7288
btf_get_ptr_to_btf_id(struct bpf_verifier_log * log,int arg_idx,const struct btf * btf,const struct btf_type * t)7289 static int btf_get_ptr_to_btf_id(struct bpf_verifier_log *log, int arg_idx,
7290 const struct btf *btf, const struct btf_type *t)
7291 {
7292 struct bpf_cand_cache *cc;
7293 struct bpf_core_ctx ctx = {
7294 .btf = btf,
7295 .log = log,
7296 };
7297 u32 kern_type_id, type_id;
7298 int err = 0;
7299
7300 /* skip PTR and modifiers */
7301 type_id = t->type;
7302 t = btf_type_by_id(btf, t->type);
7303 while (btf_type_is_modifier(t)) {
7304 type_id = t->type;
7305 t = btf_type_by_id(btf, t->type);
7306 }
7307
7308 mutex_lock(&cand_cache_mutex);
7309 cc = bpf_core_find_cands(&ctx, type_id);
7310 if (IS_ERR(cc)) {
7311 err = PTR_ERR(cc);
7312 bpf_log(log, "arg#%d reference type('%s %s') candidate matching error: %d\n",
7313 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off),
7314 err);
7315 goto cand_cache_unlock;
7316 }
7317 if (cc->cnt != 1) {
7318 bpf_log(log, "arg#%d reference type('%s %s') %s\n",
7319 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off),
7320 cc->cnt == 0 ? "has no matches" : "is ambiguous");
7321 err = cc->cnt == 0 ? -ENOENT : -ESRCH;
7322 goto cand_cache_unlock;
7323 }
7324 if (btf_is_module(cc->cands[0].btf)) {
7325 bpf_log(log, "arg#%d reference type('%s %s') points to kernel module type (unsupported)\n",
7326 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off));
7327 err = -EOPNOTSUPP;
7328 goto cand_cache_unlock;
7329 }
7330 kern_type_id = cc->cands[0].id;
7331
7332 cand_cache_unlock:
7333 mutex_unlock(&cand_cache_mutex);
7334 if (err)
7335 return err;
7336
7337 return kern_type_id;
7338 }
7339
7340 enum btf_arg_tag {
7341 ARG_TAG_CTX = BIT_ULL(0),
7342 ARG_TAG_NONNULL = BIT_ULL(1),
7343 ARG_TAG_TRUSTED = BIT_ULL(2),
7344 ARG_TAG_NULLABLE = BIT_ULL(3),
7345 ARG_TAG_ARENA = BIT_ULL(4),
7346 };
7347
7348 /* Process BTF of a function to produce high-level expectation of function
7349 * arguments (like ARG_PTR_TO_CTX, or ARG_PTR_TO_MEM, etc). This information
7350 * is cached in subprog info for reuse.
7351 * Returns:
7352 * EFAULT - there is a verifier bug. Abort verification.
7353 * EINVAL - cannot convert BTF.
7354 * 0 - Successfully processed BTF and constructed argument expectations.
7355 */
btf_prepare_func_args(struct bpf_verifier_env * env,int subprog)7356 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
7357 {
7358 bool is_global = subprog_aux(env, subprog)->linkage == BTF_FUNC_GLOBAL;
7359 struct bpf_subprog_info *sub = subprog_info(env, subprog);
7360 struct bpf_verifier_log *log = &env->log;
7361 struct bpf_prog *prog = env->prog;
7362 enum bpf_prog_type prog_type = prog->type;
7363 struct btf *btf = prog->aux->btf;
7364 const struct btf_param *args;
7365 const struct btf_type *t, *ref_t, *fn_t;
7366 u32 i, nargs, btf_id;
7367 const char *tname;
7368
7369 if (sub->args_cached)
7370 return 0;
7371
7372 if (!prog->aux->func_info) {
7373 bpf_log(log, "Verifier bug\n");
7374 return -EFAULT;
7375 }
7376
7377 btf_id = prog->aux->func_info[subprog].type_id;
7378 if (!btf_id) {
7379 if (!is_global) /* not fatal for static funcs */
7380 return -EINVAL;
7381 bpf_log(log, "Global functions need valid BTF\n");
7382 return -EFAULT;
7383 }
7384
7385 fn_t = btf_type_by_id(btf, btf_id);
7386 if (!fn_t || !btf_type_is_func(fn_t)) {
7387 /* These checks were already done by the verifier while loading
7388 * struct bpf_func_info
7389 */
7390 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
7391 subprog);
7392 return -EFAULT;
7393 }
7394 tname = btf_name_by_offset(btf, fn_t->name_off);
7395
7396 if (prog->aux->func_info_aux[subprog].unreliable) {
7397 bpf_log(log, "Verifier bug in function %s()\n", tname);
7398 return -EFAULT;
7399 }
7400 if (prog_type == BPF_PROG_TYPE_EXT)
7401 prog_type = prog->aux->dst_prog->type;
7402
7403 t = btf_type_by_id(btf, fn_t->type);
7404 if (!t || !btf_type_is_func_proto(t)) {
7405 bpf_log(log, "Invalid type of function %s()\n", tname);
7406 return -EFAULT;
7407 }
7408 args = (const struct btf_param *)(t + 1);
7409 nargs = btf_type_vlen(t);
7410 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
7411 if (!is_global)
7412 return -EINVAL;
7413 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
7414 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
7415 return -EINVAL;
7416 }
7417 /* check that function returns int, exception cb also requires this */
7418 t = btf_type_by_id(btf, t->type);
7419 while (btf_type_is_modifier(t))
7420 t = btf_type_by_id(btf, t->type);
7421 if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
7422 if (!is_global)
7423 return -EINVAL;
7424 bpf_log(log,
7425 "Global function %s() doesn't return scalar. Only those are supported.\n",
7426 tname);
7427 return -EINVAL;
7428 }
7429 /* Convert BTF function arguments into verifier types.
7430 * Only PTR_TO_CTX and SCALAR are supported atm.
7431 */
7432 for (i = 0; i < nargs; i++) {
7433 u32 tags = 0;
7434 int id = 0;
7435
7436 /* 'arg:<tag>' decl_tag takes precedence over derivation of
7437 * register type from BTF type itself
7438 */
7439 while ((id = btf_find_next_decl_tag(btf, fn_t, i, "arg:", id)) > 0) {
7440 const struct btf_type *tag_t = btf_type_by_id(btf, id);
7441 const char *tag = __btf_name_by_offset(btf, tag_t->name_off) + 4;
7442
7443 /* disallow arg tags in static subprogs */
7444 if (!is_global) {
7445 bpf_log(log, "arg#%d type tag is not supported in static functions\n", i);
7446 return -EOPNOTSUPP;
7447 }
7448
7449 if (strcmp(tag, "ctx") == 0) {
7450 tags |= ARG_TAG_CTX;
7451 } else if (strcmp(tag, "trusted") == 0) {
7452 tags |= ARG_TAG_TRUSTED;
7453 } else if (strcmp(tag, "nonnull") == 0) {
7454 tags |= ARG_TAG_NONNULL;
7455 } else if (strcmp(tag, "nullable") == 0) {
7456 tags |= ARG_TAG_NULLABLE;
7457 } else if (strcmp(tag, "arena") == 0) {
7458 tags |= ARG_TAG_ARENA;
7459 } else {
7460 bpf_log(log, "arg#%d has unsupported set of tags\n", i);
7461 return -EOPNOTSUPP;
7462 }
7463 }
7464 if (id != -ENOENT) {
7465 bpf_log(log, "arg#%d type tag fetching failure: %d\n", i, id);
7466 return id;
7467 }
7468
7469 t = btf_type_by_id(btf, args[i].type);
7470 while (btf_type_is_modifier(t))
7471 t = btf_type_by_id(btf, t->type);
7472 if (!btf_type_is_ptr(t))
7473 goto skip_pointer;
7474
7475 if ((tags & ARG_TAG_CTX) || btf_is_prog_ctx_type(log, btf, t, prog_type, i)) {
7476 if (tags & ~ARG_TAG_CTX) {
7477 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7478 return -EINVAL;
7479 }
7480 if ((tags & ARG_TAG_CTX) &&
7481 btf_validate_prog_ctx_type(log, btf, t, i, prog_type,
7482 prog->expected_attach_type))
7483 return -EINVAL;
7484 sub->args[i].arg_type = ARG_PTR_TO_CTX;
7485 continue;
7486 }
7487 if (btf_is_dynptr_ptr(btf, t)) {
7488 if (tags) {
7489 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7490 return -EINVAL;
7491 }
7492 sub->args[i].arg_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY;
7493 continue;
7494 }
7495 if (tags & ARG_TAG_TRUSTED) {
7496 int kern_type_id;
7497
7498 if (tags & ARG_TAG_NONNULL) {
7499 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7500 return -EINVAL;
7501 }
7502
7503 kern_type_id = btf_get_ptr_to_btf_id(log, i, btf, t);
7504 if (kern_type_id < 0)
7505 return kern_type_id;
7506
7507 sub->args[i].arg_type = ARG_PTR_TO_BTF_ID | PTR_TRUSTED;
7508 if (tags & ARG_TAG_NULLABLE)
7509 sub->args[i].arg_type |= PTR_MAYBE_NULL;
7510 sub->args[i].btf_id = kern_type_id;
7511 continue;
7512 }
7513 if (tags & ARG_TAG_ARENA) {
7514 if (tags & ~ARG_TAG_ARENA) {
7515 bpf_log(log, "arg#%d arena cannot be combined with any other tags\n", i);
7516 return -EINVAL;
7517 }
7518 sub->args[i].arg_type = ARG_PTR_TO_ARENA;
7519 continue;
7520 }
7521 if (is_global) { /* generic user data pointer */
7522 u32 mem_size;
7523
7524 if (tags & ARG_TAG_NULLABLE) {
7525 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7526 return -EINVAL;
7527 }
7528
7529 t = btf_type_skip_modifiers(btf, t->type, NULL);
7530 ref_t = btf_resolve_size(btf, t, &mem_size);
7531 if (IS_ERR(ref_t)) {
7532 bpf_log(log, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
7533 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
7534 PTR_ERR(ref_t));
7535 return -EINVAL;
7536 }
7537
7538 sub->args[i].arg_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL;
7539 if (tags & ARG_TAG_NONNULL)
7540 sub->args[i].arg_type &= ~PTR_MAYBE_NULL;
7541 sub->args[i].mem_size = mem_size;
7542 continue;
7543 }
7544
7545 skip_pointer:
7546 if (tags) {
7547 bpf_log(log, "arg#%d has pointer tag, but is not a pointer type\n", i);
7548 return -EINVAL;
7549 }
7550 if (btf_type_is_int(t) || btf_is_any_enum(t)) {
7551 sub->args[i].arg_type = ARG_ANYTHING;
7552 continue;
7553 }
7554 if (!is_global)
7555 return -EINVAL;
7556 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
7557 i, btf_type_str(t), tname);
7558 return -EINVAL;
7559 }
7560
7561 sub->arg_cnt = nargs;
7562 sub->args_cached = true;
7563
7564 return 0;
7565 }
7566
btf_type_show(const struct btf * btf,u32 type_id,void * obj,struct btf_show * show)7567 static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
7568 struct btf_show *show)
7569 {
7570 const struct btf_type *t = btf_type_by_id(btf, type_id);
7571
7572 show->btf = btf;
7573 memset(&show->state, 0, sizeof(show->state));
7574 memset(&show->obj, 0, sizeof(show->obj));
7575
7576 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
7577 }
7578
btf_seq_show(struct btf_show * show,const char * fmt,va_list args)7579 __printf(2, 0) static void btf_seq_show(struct btf_show *show, const char *fmt,
7580 va_list args)
7581 {
7582 seq_vprintf((struct seq_file *)show->target, fmt, args);
7583 }
7584
btf_type_seq_show_flags(const struct btf * btf,u32 type_id,void * obj,struct seq_file * m,u64 flags)7585 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
7586 void *obj, struct seq_file *m, u64 flags)
7587 {
7588 struct btf_show sseq;
7589
7590 sseq.target = m;
7591 sseq.showfn = btf_seq_show;
7592 sseq.flags = flags;
7593
7594 btf_type_show(btf, type_id, obj, &sseq);
7595
7596 return sseq.state.status;
7597 }
7598
btf_type_seq_show(const struct btf * btf,u32 type_id,void * obj,struct seq_file * m)7599 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
7600 struct seq_file *m)
7601 {
7602 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
7603 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
7604 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
7605 }
7606
7607 struct btf_show_snprintf {
7608 struct btf_show show;
7609 int len_left; /* space left in string */
7610 int len; /* length we would have written */
7611 };
7612
btf_snprintf_show(struct btf_show * show,const char * fmt,va_list args)7613 __printf(2, 0) static void btf_snprintf_show(struct btf_show *show, const char *fmt,
7614 va_list args)
7615 {
7616 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
7617 int len;
7618
7619 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
7620
7621 if (len < 0) {
7622 ssnprintf->len_left = 0;
7623 ssnprintf->len = len;
7624 } else if (len >= ssnprintf->len_left) {
7625 /* no space, drive on to get length we would have written */
7626 ssnprintf->len_left = 0;
7627 ssnprintf->len += len;
7628 } else {
7629 ssnprintf->len_left -= len;
7630 ssnprintf->len += len;
7631 show->target += len;
7632 }
7633 }
7634
btf_type_snprintf_show(const struct btf * btf,u32 type_id,void * obj,char * buf,int len,u64 flags)7635 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
7636 char *buf, int len, u64 flags)
7637 {
7638 struct btf_show_snprintf ssnprintf;
7639
7640 ssnprintf.show.target = buf;
7641 ssnprintf.show.flags = flags;
7642 ssnprintf.show.showfn = btf_snprintf_show;
7643 ssnprintf.len_left = len;
7644 ssnprintf.len = 0;
7645
7646 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
7647
7648 /* If we encountered an error, return it. */
7649 if (ssnprintf.show.state.status)
7650 return ssnprintf.show.state.status;
7651
7652 /* Otherwise return length we would have written */
7653 return ssnprintf.len;
7654 }
7655
7656 #ifdef CONFIG_PROC_FS
bpf_btf_show_fdinfo(struct seq_file * m,struct file * filp)7657 static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
7658 {
7659 const struct btf *btf = filp->private_data;
7660
7661 seq_printf(m, "btf_id:\t%u\n", btf->id);
7662 }
7663 #endif
7664
btf_release(struct inode * inode,struct file * filp)7665 static int btf_release(struct inode *inode, struct file *filp)
7666 {
7667 btf_put(filp->private_data);
7668 return 0;
7669 }
7670
7671 const struct file_operations btf_fops = {
7672 #ifdef CONFIG_PROC_FS
7673 .show_fdinfo = bpf_btf_show_fdinfo,
7674 #endif
7675 .release = btf_release,
7676 };
7677
__btf_new_fd(struct btf * btf)7678 static int __btf_new_fd(struct btf *btf)
7679 {
7680 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
7681 }
7682
btf_new_fd(const union bpf_attr * attr,bpfptr_t uattr,u32 uattr_size)7683 int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
7684 {
7685 struct btf *btf;
7686 int ret;
7687
7688 btf = btf_parse(attr, uattr, uattr_size);
7689 if (IS_ERR(btf))
7690 return PTR_ERR(btf);
7691
7692 ret = btf_alloc_id(btf);
7693 if (ret) {
7694 btf_free(btf);
7695 return ret;
7696 }
7697
7698 /*
7699 * The BTF ID is published to the userspace.
7700 * All BTF free must go through call_rcu() from
7701 * now on (i.e. free by calling btf_put()).
7702 */
7703
7704 ret = __btf_new_fd(btf);
7705 if (ret < 0)
7706 btf_put(btf);
7707
7708 return ret;
7709 }
7710
btf_get_by_fd(int fd)7711 struct btf *btf_get_by_fd(int fd)
7712 {
7713 struct btf *btf;
7714 CLASS(fd, f)(fd);
7715
7716 if (fd_empty(f))
7717 return ERR_PTR(-EBADF);
7718
7719 if (fd_file(f)->f_op != &btf_fops)
7720 return ERR_PTR(-EINVAL);
7721
7722 btf = fd_file(f)->private_data;
7723 refcount_inc(&btf->refcnt);
7724
7725 return btf;
7726 }
7727
btf_get_info_by_fd(const struct btf * btf,const union bpf_attr * attr,union bpf_attr __user * uattr)7728 int btf_get_info_by_fd(const struct btf *btf,
7729 const union bpf_attr *attr,
7730 union bpf_attr __user *uattr)
7731 {
7732 struct bpf_btf_info __user *uinfo;
7733 struct bpf_btf_info info;
7734 u32 info_copy, btf_copy;
7735 void __user *ubtf;
7736 char __user *uname;
7737 u32 uinfo_len, uname_len, name_len;
7738 int ret = 0;
7739
7740 uinfo = u64_to_user_ptr(attr->info.info);
7741 uinfo_len = attr->info.info_len;
7742
7743 info_copy = min_t(u32, uinfo_len, sizeof(info));
7744 memset(&info, 0, sizeof(info));
7745 if (copy_from_user(&info, uinfo, info_copy))
7746 return -EFAULT;
7747
7748 info.id = btf->id;
7749 ubtf = u64_to_user_ptr(info.btf);
7750 btf_copy = min_t(u32, btf->data_size, info.btf_size);
7751 if (copy_to_user(ubtf, btf->data, btf_copy))
7752 return -EFAULT;
7753 info.btf_size = btf->data_size;
7754
7755 info.kernel_btf = btf->kernel_btf;
7756
7757 uname = u64_to_user_ptr(info.name);
7758 uname_len = info.name_len;
7759 if (!uname ^ !uname_len)
7760 return -EINVAL;
7761
7762 name_len = strlen(btf->name);
7763 info.name_len = name_len;
7764
7765 if (uname) {
7766 if (uname_len >= name_len + 1) {
7767 if (copy_to_user(uname, btf->name, name_len + 1))
7768 return -EFAULT;
7769 } else {
7770 char zero = '\0';
7771
7772 if (copy_to_user(uname, btf->name, uname_len - 1))
7773 return -EFAULT;
7774 if (put_user(zero, uname + uname_len - 1))
7775 return -EFAULT;
7776 /* let user-space know about too short buffer */
7777 ret = -ENOSPC;
7778 }
7779 }
7780
7781 if (copy_to_user(uinfo, &info, info_copy) ||
7782 put_user(info_copy, &uattr->info.info_len))
7783 return -EFAULT;
7784
7785 return ret;
7786 }
7787
btf_get_fd_by_id(u32 id)7788 int btf_get_fd_by_id(u32 id)
7789 {
7790 struct btf *btf;
7791 int fd;
7792
7793 rcu_read_lock();
7794 btf = idr_find(&btf_idr, id);
7795 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
7796 btf = ERR_PTR(-ENOENT);
7797 rcu_read_unlock();
7798
7799 if (IS_ERR(btf))
7800 return PTR_ERR(btf);
7801
7802 fd = __btf_new_fd(btf);
7803 if (fd < 0)
7804 btf_put(btf);
7805
7806 return fd;
7807 }
7808
btf_obj_id(const struct btf * btf)7809 u32 btf_obj_id(const struct btf *btf)
7810 {
7811 return btf->id;
7812 }
7813
btf_is_kernel(const struct btf * btf)7814 bool btf_is_kernel(const struct btf *btf)
7815 {
7816 return btf->kernel_btf;
7817 }
7818
btf_is_module(const struct btf * btf)7819 bool btf_is_module(const struct btf *btf)
7820 {
7821 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
7822 }
7823
7824 enum {
7825 BTF_MODULE_F_LIVE = (1 << 0),
7826 };
7827
7828 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7829 struct btf_module {
7830 struct list_head list;
7831 struct module *module;
7832 struct btf *btf;
7833 struct bin_attribute *sysfs_attr;
7834 int flags;
7835 };
7836
7837 static LIST_HEAD(btf_modules);
7838 static DEFINE_MUTEX(btf_module_mutex);
7839
7840 static ssize_t
btf_module_read(struct file * file,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t len)7841 btf_module_read(struct file *file, struct kobject *kobj,
7842 struct bin_attribute *bin_attr,
7843 char *buf, loff_t off, size_t len)
7844 {
7845 const struct btf *btf = bin_attr->private;
7846
7847 memcpy(buf, btf->data + off, len);
7848 return len;
7849 }
7850
7851 static void purge_cand_cache(struct btf *btf);
7852
btf_module_notify(struct notifier_block * nb,unsigned long op,void * module)7853 static int btf_module_notify(struct notifier_block *nb, unsigned long op,
7854 void *module)
7855 {
7856 struct btf_module *btf_mod, *tmp;
7857 struct module *mod = module;
7858 struct btf *btf;
7859 int err = 0;
7860
7861 if (mod->btf_data_size == 0 ||
7862 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
7863 op != MODULE_STATE_GOING))
7864 goto out;
7865
7866 switch (op) {
7867 case MODULE_STATE_COMING:
7868 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
7869 if (!btf_mod) {
7870 err = -ENOMEM;
7871 goto out;
7872 }
7873 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size,
7874 mod->btf_base_data, mod->btf_base_data_size);
7875 if (IS_ERR(btf)) {
7876 kfree(btf_mod);
7877 if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH)) {
7878 pr_warn("failed to validate module [%s] BTF: %ld\n",
7879 mod->name, PTR_ERR(btf));
7880 err = PTR_ERR(btf);
7881 } else {
7882 pr_warn_once("Kernel module BTF mismatch detected, BTF debug info may be unavailable for some modules\n");
7883 }
7884 goto out;
7885 }
7886 err = btf_alloc_id(btf);
7887 if (err) {
7888 btf_free(btf);
7889 kfree(btf_mod);
7890 goto out;
7891 }
7892
7893 purge_cand_cache(NULL);
7894 mutex_lock(&btf_module_mutex);
7895 btf_mod->module = module;
7896 btf_mod->btf = btf;
7897 list_add(&btf_mod->list, &btf_modules);
7898 mutex_unlock(&btf_module_mutex);
7899
7900 if (IS_ENABLED(CONFIG_SYSFS)) {
7901 struct bin_attribute *attr;
7902
7903 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
7904 if (!attr)
7905 goto out;
7906
7907 sysfs_bin_attr_init(attr);
7908 attr->attr.name = btf->name;
7909 attr->attr.mode = 0444;
7910 attr->size = btf->data_size;
7911 attr->private = btf;
7912 attr->read = btf_module_read;
7913
7914 err = sysfs_create_bin_file(btf_kobj, attr);
7915 if (err) {
7916 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
7917 mod->name, err);
7918 kfree(attr);
7919 err = 0;
7920 goto out;
7921 }
7922
7923 btf_mod->sysfs_attr = attr;
7924 }
7925
7926 break;
7927 case MODULE_STATE_LIVE:
7928 mutex_lock(&btf_module_mutex);
7929 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7930 if (btf_mod->module != module)
7931 continue;
7932
7933 btf_mod->flags |= BTF_MODULE_F_LIVE;
7934 break;
7935 }
7936 mutex_unlock(&btf_module_mutex);
7937 break;
7938 case MODULE_STATE_GOING:
7939 mutex_lock(&btf_module_mutex);
7940 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7941 if (btf_mod->module != module)
7942 continue;
7943
7944 list_del(&btf_mod->list);
7945 if (btf_mod->sysfs_attr)
7946 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
7947 purge_cand_cache(btf_mod->btf);
7948 btf_put(btf_mod->btf);
7949 kfree(btf_mod->sysfs_attr);
7950 kfree(btf_mod);
7951 break;
7952 }
7953 mutex_unlock(&btf_module_mutex);
7954 break;
7955 }
7956 out:
7957 return notifier_from_errno(err);
7958 }
7959
7960 static struct notifier_block btf_module_nb = {
7961 .notifier_call = btf_module_notify,
7962 };
7963
btf_module_init(void)7964 static int __init btf_module_init(void)
7965 {
7966 register_module_notifier(&btf_module_nb);
7967 return 0;
7968 }
7969
7970 fs_initcall(btf_module_init);
7971 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
7972
btf_try_get_module(const struct btf * btf)7973 struct module *btf_try_get_module(const struct btf *btf)
7974 {
7975 struct module *res = NULL;
7976 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7977 struct btf_module *btf_mod, *tmp;
7978
7979 mutex_lock(&btf_module_mutex);
7980 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7981 if (btf_mod->btf != btf)
7982 continue;
7983
7984 /* We must only consider module whose __init routine has
7985 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
7986 * which is set from the notifier callback for
7987 * MODULE_STATE_LIVE.
7988 */
7989 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
7990 res = btf_mod->module;
7991
7992 break;
7993 }
7994 mutex_unlock(&btf_module_mutex);
7995 #endif
7996
7997 return res;
7998 }
7999
8000 /* Returns struct btf corresponding to the struct module.
8001 * This function can return NULL or ERR_PTR.
8002 */
btf_get_module_btf(const struct module * module)8003 static struct btf *btf_get_module_btf(const struct module *module)
8004 {
8005 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8006 struct btf_module *btf_mod, *tmp;
8007 #endif
8008 struct btf *btf = NULL;
8009
8010 if (!module) {
8011 btf = bpf_get_btf_vmlinux();
8012 if (!IS_ERR_OR_NULL(btf))
8013 btf_get(btf);
8014 return btf;
8015 }
8016
8017 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8018 mutex_lock(&btf_module_mutex);
8019 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8020 if (btf_mod->module != module)
8021 continue;
8022
8023 btf_get(btf_mod->btf);
8024 btf = btf_mod->btf;
8025 break;
8026 }
8027 mutex_unlock(&btf_module_mutex);
8028 #endif
8029
8030 return btf;
8031 }
8032
check_btf_kconfigs(const struct module * module,const char * feature)8033 static int check_btf_kconfigs(const struct module *module, const char *feature)
8034 {
8035 if (!module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
8036 pr_err("missing vmlinux BTF, cannot register %s\n", feature);
8037 return -ENOENT;
8038 }
8039 if (module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
8040 pr_warn("missing module BTF, cannot register %s\n", feature);
8041 return 0;
8042 }
8043
BPF_CALL_4(bpf_btf_find_by_name_kind,char *,name,int,name_sz,u32,kind,int,flags)8044 BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
8045 {
8046 struct btf *btf = NULL;
8047 int btf_obj_fd = 0;
8048 long ret;
8049
8050 if (flags)
8051 return -EINVAL;
8052
8053 if (name_sz <= 1 || name[name_sz - 1])
8054 return -EINVAL;
8055
8056 ret = bpf_find_btf_id(name, kind, &btf);
8057 if (ret > 0 && btf_is_module(btf)) {
8058 btf_obj_fd = __btf_new_fd(btf);
8059 if (btf_obj_fd < 0) {
8060 btf_put(btf);
8061 return btf_obj_fd;
8062 }
8063 return ret | (((u64)btf_obj_fd) << 32);
8064 }
8065 if (ret > 0)
8066 btf_put(btf);
8067 return ret;
8068 }
8069
8070 const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
8071 .func = bpf_btf_find_by_name_kind,
8072 .gpl_only = false,
8073 .ret_type = RET_INTEGER,
8074 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
8075 .arg2_type = ARG_CONST_SIZE,
8076 .arg3_type = ARG_ANYTHING,
8077 .arg4_type = ARG_ANYTHING,
8078 };
8079
BTF_ID_LIST_GLOBAL(btf_tracing_ids,MAX_BTF_TRACING_TYPE)8080 BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
8081 #define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
8082 BTF_TRACING_TYPE_xxx
8083 #undef BTF_TRACING_TYPE
8084
8085 /* Validate well-formedness of iter argument type.
8086 * On success, return positive BTF ID of iter state's STRUCT type.
8087 * On error, negative error is returned.
8088 */
8089 int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx)
8090 {
8091 const struct btf_param *arg;
8092 const struct btf_type *t;
8093 const char *name;
8094 int btf_id;
8095
8096 if (btf_type_vlen(func) <= arg_idx)
8097 return -EINVAL;
8098
8099 arg = &btf_params(func)[arg_idx];
8100 t = btf_type_skip_modifiers(btf, arg->type, NULL);
8101 if (!t || !btf_type_is_ptr(t))
8102 return -EINVAL;
8103 t = btf_type_skip_modifiers(btf, t->type, &btf_id);
8104 if (!t || !__btf_type_is_struct(t))
8105 return -EINVAL;
8106
8107 name = btf_name_by_offset(btf, t->name_off);
8108 if (!name || strncmp(name, ITER_PREFIX, sizeof(ITER_PREFIX) - 1))
8109 return -EINVAL;
8110
8111 return btf_id;
8112 }
8113
btf_check_iter_kfuncs(struct btf * btf,const char * func_name,const struct btf_type * func,u32 func_flags)8114 static int btf_check_iter_kfuncs(struct btf *btf, const char *func_name,
8115 const struct btf_type *func, u32 func_flags)
8116 {
8117 u32 flags = func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
8118 const char *sfx, *iter_name;
8119 const struct btf_type *t;
8120 char exp_name[128];
8121 u32 nr_args;
8122 int btf_id;
8123
8124 /* exactly one of KF_ITER_{NEW,NEXT,DESTROY} can be set */
8125 if (!flags || (flags & (flags - 1)))
8126 return -EINVAL;
8127
8128 /* any BPF iter kfunc should have `struct bpf_iter_<type> *` first arg */
8129 nr_args = btf_type_vlen(func);
8130 if (nr_args < 1)
8131 return -EINVAL;
8132
8133 btf_id = btf_check_iter_arg(btf, func, 0);
8134 if (btf_id < 0)
8135 return btf_id;
8136
8137 /* sizeof(struct bpf_iter_<type>) should be a multiple of 8 to
8138 * fit nicely in stack slots
8139 */
8140 t = btf_type_by_id(btf, btf_id);
8141 if (t->size == 0 || (t->size % 8))
8142 return -EINVAL;
8143
8144 /* validate bpf_iter_<type>_{new,next,destroy}(struct bpf_iter_<type> *)
8145 * naming pattern
8146 */
8147 iter_name = btf_name_by_offset(btf, t->name_off) + sizeof(ITER_PREFIX) - 1;
8148 if (flags & KF_ITER_NEW)
8149 sfx = "new";
8150 else if (flags & KF_ITER_NEXT)
8151 sfx = "next";
8152 else /* (flags & KF_ITER_DESTROY) */
8153 sfx = "destroy";
8154
8155 snprintf(exp_name, sizeof(exp_name), "bpf_iter_%s_%s", iter_name, sfx);
8156 if (strcmp(func_name, exp_name))
8157 return -EINVAL;
8158
8159 /* only iter constructor should have extra arguments */
8160 if (!(flags & KF_ITER_NEW) && nr_args != 1)
8161 return -EINVAL;
8162
8163 if (flags & KF_ITER_NEXT) {
8164 /* bpf_iter_<type>_next() should return pointer */
8165 t = btf_type_skip_modifiers(btf, func->type, NULL);
8166 if (!t || !btf_type_is_ptr(t))
8167 return -EINVAL;
8168 }
8169
8170 if (flags & KF_ITER_DESTROY) {
8171 /* bpf_iter_<type>_destroy() should return void */
8172 t = btf_type_by_id(btf, func->type);
8173 if (!t || !btf_type_is_void(t))
8174 return -EINVAL;
8175 }
8176
8177 return 0;
8178 }
8179
btf_check_kfunc_protos(struct btf * btf,u32 func_id,u32 func_flags)8180 static int btf_check_kfunc_protos(struct btf *btf, u32 func_id, u32 func_flags)
8181 {
8182 const struct btf_type *func;
8183 const char *func_name;
8184 int err;
8185
8186 /* any kfunc should be FUNC -> FUNC_PROTO */
8187 func = btf_type_by_id(btf, func_id);
8188 if (!func || !btf_type_is_func(func))
8189 return -EINVAL;
8190
8191 /* sanity check kfunc name */
8192 func_name = btf_name_by_offset(btf, func->name_off);
8193 if (!func_name || !func_name[0])
8194 return -EINVAL;
8195
8196 func = btf_type_by_id(btf, func->type);
8197 if (!func || !btf_type_is_func_proto(func))
8198 return -EINVAL;
8199
8200 if (func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY)) {
8201 err = btf_check_iter_kfuncs(btf, func_name, func, func_flags);
8202 if (err)
8203 return err;
8204 }
8205
8206 return 0;
8207 }
8208
8209 /* Kernel Function (kfunc) BTF ID set registration API */
8210
btf_populate_kfunc_set(struct btf * btf,enum btf_kfunc_hook hook,const struct btf_kfunc_id_set * kset)8211 static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
8212 const struct btf_kfunc_id_set *kset)
8213 {
8214 struct btf_kfunc_hook_filter *hook_filter;
8215 struct btf_id_set8 *add_set = kset->set;
8216 bool vmlinux_set = !btf_is_module(btf);
8217 bool add_filter = !!kset->filter;
8218 struct btf_kfunc_set_tab *tab;
8219 struct btf_id_set8 *set;
8220 u32 set_cnt, i;
8221 int ret;
8222
8223 if (hook >= BTF_KFUNC_HOOK_MAX) {
8224 ret = -EINVAL;
8225 goto end;
8226 }
8227
8228 if (!add_set->cnt)
8229 return 0;
8230
8231 tab = btf->kfunc_set_tab;
8232
8233 if (tab && add_filter) {
8234 u32 i;
8235
8236 hook_filter = &tab->hook_filters[hook];
8237 for (i = 0; i < hook_filter->nr_filters; i++) {
8238 if (hook_filter->filters[i] == kset->filter) {
8239 add_filter = false;
8240 break;
8241 }
8242 }
8243
8244 if (add_filter && hook_filter->nr_filters == BTF_KFUNC_FILTER_MAX_CNT) {
8245 ret = -E2BIG;
8246 goto end;
8247 }
8248 }
8249
8250 if (!tab) {
8251 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
8252 if (!tab)
8253 return -ENOMEM;
8254 btf->kfunc_set_tab = tab;
8255 }
8256
8257 set = tab->sets[hook];
8258 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
8259 * for module sets.
8260 */
8261 if (WARN_ON_ONCE(set && !vmlinux_set)) {
8262 ret = -EINVAL;
8263 goto end;
8264 }
8265
8266 /* In case of vmlinux sets, there may be more than one set being
8267 * registered per hook. To create a unified set, we allocate a new set
8268 * and concatenate all individual sets being registered. While each set
8269 * is individually sorted, they may become unsorted when concatenated,
8270 * hence re-sorting the final set again is required to make binary
8271 * searching the set using btf_id_set8_contains function work.
8272 *
8273 * For module sets, we need to allocate as we may need to relocate
8274 * BTF ids.
8275 */
8276 set_cnt = set ? set->cnt : 0;
8277
8278 if (set_cnt > U32_MAX - add_set->cnt) {
8279 ret = -EOVERFLOW;
8280 goto end;
8281 }
8282
8283 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
8284 ret = -E2BIG;
8285 goto end;
8286 }
8287
8288 /* Grow set */
8289 set = krealloc(tab->sets[hook],
8290 offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
8291 GFP_KERNEL | __GFP_NOWARN);
8292 if (!set) {
8293 ret = -ENOMEM;
8294 goto end;
8295 }
8296
8297 /* For newly allocated set, initialize set->cnt to 0 */
8298 if (!tab->sets[hook])
8299 set->cnt = 0;
8300 tab->sets[hook] = set;
8301
8302 /* Concatenate the two sets */
8303 memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
8304 /* Now that the set is copied, update with relocated BTF ids */
8305 for (i = set->cnt; i < set->cnt + add_set->cnt; i++)
8306 set->pairs[i].id = btf_relocate_id(btf, set->pairs[i].id);
8307
8308 set->cnt += add_set->cnt;
8309
8310 sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
8311
8312 if (add_filter) {
8313 hook_filter = &tab->hook_filters[hook];
8314 hook_filter->filters[hook_filter->nr_filters++] = kset->filter;
8315 }
8316 return 0;
8317 end:
8318 btf_free_kfunc_set_tab(btf);
8319 return ret;
8320 }
8321
__btf_kfunc_id_set_contains(const struct btf * btf,enum btf_kfunc_hook hook,u32 kfunc_btf_id,const struct bpf_prog * prog)8322 static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
8323 enum btf_kfunc_hook hook,
8324 u32 kfunc_btf_id,
8325 const struct bpf_prog *prog)
8326 {
8327 struct btf_kfunc_hook_filter *hook_filter;
8328 struct btf_id_set8 *set;
8329 u32 *id, i;
8330
8331 if (hook >= BTF_KFUNC_HOOK_MAX)
8332 return NULL;
8333 if (!btf->kfunc_set_tab)
8334 return NULL;
8335 hook_filter = &btf->kfunc_set_tab->hook_filters[hook];
8336 for (i = 0; i < hook_filter->nr_filters; i++) {
8337 if (hook_filter->filters[i](prog, kfunc_btf_id))
8338 return NULL;
8339 }
8340 set = btf->kfunc_set_tab->sets[hook];
8341 if (!set)
8342 return NULL;
8343 id = btf_id_set8_contains(set, kfunc_btf_id);
8344 if (!id)
8345 return NULL;
8346 /* The flags for BTF ID are located next to it */
8347 return id + 1;
8348 }
8349
bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)8350 static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
8351 {
8352 switch (prog_type) {
8353 case BPF_PROG_TYPE_UNSPEC:
8354 return BTF_KFUNC_HOOK_COMMON;
8355 case BPF_PROG_TYPE_XDP:
8356 return BTF_KFUNC_HOOK_XDP;
8357 case BPF_PROG_TYPE_SCHED_CLS:
8358 return BTF_KFUNC_HOOK_TC;
8359 case BPF_PROG_TYPE_STRUCT_OPS:
8360 return BTF_KFUNC_HOOK_STRUCT_OPS;
8361 case BPF_PROG_TYPE_TRACING:
8362 case BPF_PROG_TYPE_TRACEPOINT:
8363 case BPF_PROG_TYPE_PERF_EVENT:
8364 case BPF_PROG_TYPE_LSM:
8365 return BTF_KFUNC_HOOK_TRACING;
8366 case BPF_PROG_TYPE_SYSCALL:
8367 return BTF_KFUNC_HOOK_SYSCALL;
8368 case BPF_PROG_TYPE_CGROUP_SKB:
8369 case BPF_PROG_TYPE_CGROUP_SOCK:
8370 case BPF_PROG_TYPE_CGROUP_DEVICE:
8371 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
8372 case BPF_PROG_TYPE_CGROUP_SOCKOPT:
8373 case BPF_PROG_TYPE_CGROUP_SYSCTL:
8374 return BTF_KFUNC_HOOK_CGROUP;
8375 case BPF_PROG_TYPE_SCHED_ACT:
8376 return BTF_KFUNC_HOOK_SCHED_ACT;
8377 case BPF_PROG_TYPE_SK_SKB:
8378 return BTF_KFUNC_HOOK_SK_SKB;
8379 case BPF_PROG_TYPE_SOCKET_FILTER:
8380 return BTF_KFUNC_HOOK_SOCKET_FILTER;
8381 case BPF_PROG_TYPE_LWT_OUT:
8382 case BPF_PROG_TYPE_LWT_IN:
8383 case BPF_PROG_TYPE_LWT_XMIT:
8384 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
8385 return BTF_KFUNC_HOOK_LWT;
8386 case BPF_PROG_TYPE_NETFILTER:
8387 return BTF_KFUNC_HOOK_NETFILTER;
8388 case BPF_PROG_TYPE_KPROBE:
8389 return BTF_KFUNC_HOOK_KPROBE;
8390 default:
8391 return BTF_KFUNC_HOOK_MAX;
8392 }
8393 }
8394
8395 /* Caution:
8396 * Reference to the module (obtained using btf_try_get_module) corresponding to
8397 * the struct btf *MUST* be held when calling this function from verifier
8398 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
8399 * keeping the reference for the duration of the call provides the necessary
8400 * protection for looking up a well-formed btf->kfunc_set_tab.
8401 */
btf_kfunc_id_set_contains(const struct btf * btf,u32 kfunc_btf_id,const struct bpf_prog * prog)8402 u32 *btf_kfunc_id_set_contains(const struct btf *btf,
8403 u32 kfunc_btf_id,
8404 const struct bpf_prog *prog)
8405 {
8406 enum bpf_prog_type prog_type = resolve_prog_type(prog);
8407 enum btf_kfunc_hook hook;
8408 u32 *kfunc_flags;
8409
8410 kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id, prog);
8411 if (kfunc_flags)
8412 return kfunc_flags;
8413
8414 hook = bpf_prog_type_to_kfunc_hook(prog_type);
8415 return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id, prog);
8416 }
8417
btf_kfunc_is_modify_return(const struct btf * btf,u32 kfunc_btf_id,const struct bpf_prog * prog)8418 u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
8419 const struct bpf_prog *prog)
8420 {
8421 return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id, prog);
8422 }
8423
__register_btf_kfunc_id_set(enum btf_kfunc_hook hook,const struct btf_kfunc_id_set * kset)8424 static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
8425 const struct btf_kfunc_id_set *kset)
8426 {
8427 struct btf *btf;
8428 int ret, i;
8429
8430 btf = btf_get_module_btf(kset->owner);
8431 if (!btf)
8432 return check_btf_kconfigs(kset->owner, "kfunc");
8433 if (IS_ERR(btf))
8434 return PTR_ERR(btf);
8435
8436 for (i = 0; i < kset->set->cnt; i++) {
8437 ret = btf_check_kfunc_protos(btf, btf_relocate_id(btf, kset->set->pairs[i].id),
8438 kset->set->pairs[i].flags);
8439 if (ret)
8440 goto err_out;
8441 }
8442
8443 ret = btf_populate_kfunc_set(btf, hook, kset);
8444
8445 err_out:
8446 btf_put(btf);
8447 return ret;
8448 }
8449
8450 /* This function must be invoked only from initcalls/module init functions */
register_btf_kfunc_id_set(enum bpf_prog_type prog_type,const struct btf_kfunc_id_set * kset)8451 int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
8452 const struct btf_kfunc_id_set *kset)
8453 {
8454 enum btf_kfunc_hook hook;
8455
8456 /* All kfuncs need to be tagged as such in BTF.
8457 * WARN() for initcall registrations that do not check errors.
8458 */
8459 if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
8460 WARN_ON(!kset->owner);
8461 return -EINVAL;
8462 }
8463
8464 hook = bpf_prog_type_to_kfunc_hook(prog_type);
8465 return __register_btf_kfunc_id_set(hook, kset);
8466 }
8467 EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
8468
8469 /* This function must be invoked only from initcalls/module init functions */
register_btf_fmodret_id_set(const struct btf_kfunc_id_set * kset)8470 int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset)
8471 {
8472 return __register_btf_kfunc_id_set(BTF_KFUNC_HOOK_FMODRET, kset);
8473 }
8474 EXPORT_SYMBOL_GPL(register_btf_fmodret_id_set);
8475
btf_find_dtor_kfunc(struct btf * btf,u32 btf_id)8476 s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
8477 {
8478 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
8479 struct btf_id_dtor_kfunc *dtor;
8480
8481 if (!tab)
8482 return -ENOENT;
8483 /* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
8484 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
8485 */
8486 BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
8487 dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
8488 if (!dtor)
8489 return -ENOENT;
8490 return dtor->kfunc_btf_id;
8491 }
8492
btf_check_dtor_kfuncs(struct btf * btf,const struct btf_id_dtor_kfunc * dtors,u32 cnt)8493 static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
8494 {
8495 const struct btf_type *dtor_func, *dtor_func_proto, *t;
8496 const struct btf_param *args;
8497 s32 dtor_btf_id;
8498 u32 nr_args, i;
8499
8500 for (i = 0; i < cnt; i++) {
8501 dtor_btf_id = btf_relocate_id(btf, dtors[i].kfunc_btf_id);
8502
8503 dtor_func = btf_type_by_id(btf, dtor_btf_id);
8504 if (!dtor_func || !btf_type_is_func(dtor_func))
8505 return -EINVAL;
8506
8507 dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
8508 if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
8509 return -EINVAL;
8510
8511 /* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
8512 t = btf_type_by_id(btf, dtor_func_proto->type);
8513 if (!t || !btf_type_is_void(t))
8514 return -EINVAL;
8515
8516 nr_args = btf_type_vlen(dtor_func_proto);
8517 if (nr_args != 1)
8518 return -EINVAL;
8519 args = btf_params(dtor_func_proto);
8520 t = btf_type_by_id(btf, args[0].type);
8521 /* Allow any pointer type, as width on targets Linux supports
8522 * will be same for all pointer types (i.e. sizeof(void *))
8523 */
8524 if (!t || !btf_type_is_ptr(t))
8525 return -EINVAL;
8526 }
8527 return 0;
8528 }
8529
8530 /* This function must be invoked only from initcalls/module init functions */
register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc * dtors,u32 add_cnt,struct module * owner)8531 int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
8532 struct module *owner)
8533 {
8534 struct btf_id_dtor_kfunc_tab *tab;
8535 struct btf *btf;
8536 u32 tab_cnt, i;
8537 int ret;
8538
8539 btf = btf_get_module_btf(owner);
8540 if (!btf)
8541 return check_btf_kconfigs(owner, "dtor kfuncs");
8542 if (IS_ERR(btf))
8543 return PTR_ERR(btf);
8544
8545 if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8546 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8547 ret = -E2BIG;
8548 goto end;
8549 }
8550
8551 /* Ensure that the prototype of dtor kfuncs being registered is sane */
8552 ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
8553 if (ret < 0)
8554 goto end;
8555
8556 tab = btf->dtor_kfunc_tab;
8557 /* Only one call allowed for modules */
8558 if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
8559 ret = -EINVAL;
8560 goto end;
8561 }
8562
8563 tab_cnt = tab ? tab->cnt : 0;
8564 if (tab_cnt > U32_MAX - add_cnt) {
8565 ret = -EOVERFLOW;
8566 goto end;
8567 }
8568 if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8569 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8570 ret = -E2BIG;
8571 goto end;
8572 }
8573
8574 tab = krealloc(btf->dtor_kfunc_tab,
8575 offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
8576 GFP_KERNEL | __GFP_NOWARN);
8577 if (!tab) {
8578 ret = -ENOMEM;
8579 goto end;
8580 }
8581
8582 if (!btf->dtor_kfunc_tab)
8583 tab->cnt = 0;
8584 btf->dtor_kfunc_tab = tab;
8585
8586 memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
8587
8588 /* remap BTF ids based on BTF relocation (if any) */
8589 for (i = tab_cnt; i < tab_cnt + add_cnt; i++) {
8590 tab->dtors[i].btf_id = btf_relocate_id(btf, tab->dtors[i].btf_id);
8591 tab->dtors[i].kfunc_btf_id = btf_relocate_id(btf, tab->dtors[i].kfunc_btf_id);
8592 }
8593
8594 tab->cnt += add_cnt;
8595
8596 sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
8597
8598 end:
8599 if (ret)
8600 btf_free_dtor_kfunc_tab(btf);
8601 btf_put(btf);
8602 return ret;
8603 }
8604 EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
8605
8606 #define MAX_TYPES_ARE_COMPAT_DEPTH 2
8607
8608 /* Check local and target types for compatibility. This check is used for
8609 * type-based CO-RE relocations and follow slightly different rules than
8610 * field-based relocations. This function assumes that root types were already
8611 * checked for name match. Beyond that initial root-level name check, names
8612 * are completely ignored. Compatibility rules are as follows:
8613 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
8614 * kind should match for local and target types (i.e., STRUCT is not
8615 * compatible with UNION);
8616 * - for ENUMs/ENUM64s, the size is ignored;
8617 * - for INT, size and signedness are ignored;
8618 * - for ARRAY, dimensionality is ignored, element types are checked for
8619 * compatibility recursively;
8620 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
8621 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
8622 * - FUNC_PROTOs are compatible if they have compatible signature: same
8623 * number of input args and compatible return and argument types.
8624 * These rules are not set in stone and probably will be adjusted as we get
8625 * more experience with using BPF CO-RE relocations.
8626 */
bpf_core_types_are_compat(const struct btf * local_btf,__u32 local_id,const struct btf * targ_btf,__u32 targ_id)8627 int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
8628 const struct btf *targ_btf, __u32 targ_id)
8629 {
8630 return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
8631 MAX_TYPES_ARE_COMPAT_DEPTH);
8632 }
8633
8634 #define MAX_TYPES_MATCH_DEPTH 2
8635
bpf_core_types_match(const struct btf * local_btf,u32 local_id,const struct btf * targ_btf,u32 targ_id)8636 int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
8637 const struct btf *targ_btf, u32 targ_id)
8638 {
8639 return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
8640 MAX_TYPES_MATCH_DEPTH);
8641 }
8642
bpf_core_is_flavor_sep(const char * s)8643 static bool bpf_core_is_flavor_sep(const char *s)
8644 {
8645 /* check X___Y name pattern, where X and Y are not underscores */
8646 return s[0] != '_' && /* X */
8647 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
8648 s[4] != '_'; /* Y */
8649 }
8650
bpf_core_essential_name_len(const char * name)8651 size_t bpf_core_essential_name_len(const char *name)
8652 {
8653 size_t n = strlen(name);
8654 int i;
8655
8656 for (i = n - 5; i >= 0; i--) {
8657 if (bpf_core_is_flavor_sep(name + i))
8658 return i + 1;
8659 }
8660 return n;
8661 }
8662
bpf_free_cands(struct bpf_cand_cache * cands)8663 static void bpf_free_cands(struct bpf_cand_cache *cands)
8664 {
8665 if (!cands->cnt)
8666 /* empty candidate array was allocated on stack */
8667 return;
8668 kfree(cands);
8669 }
8670
bpf_free_cands_from_cache(struct bpf_cand_cache * cands)8671 static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
8672 {
8673 kfree(cands->name);
8674 kfree(cands);
8675 }
8676
8677 #define VMLINUX_CAND_CACHE_SIZE 31
8678 static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
8679
8680 #define MODULE_CAND_CACHE_SIZE 31
8681 static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
8682
__print_cand_cache(struct bpf_verifier_log * log,struct bpf_cand_cache ** cache,int cache_size)8683 static void __print_cand_cache(struct bpf_verifier_log *log,
8684 struct bpf_cand_cache **cache,
8685 int cache_size)
8686 {
8687 struct bpf_cand_cache *cc;
8688 int i, j;
8689
8690 for (i = 0; i < cache_size; i++) {
8691 cc = cache[i];
8692 if (!cc)
8693 continue;
8694 bpf_log(log, "[%d]%s(", i, cc->name);
8695 for (j = 0; j < cc->cnt; j++) {
8696 bpf_log(log, "%d", cc->cands[j].id);
8697 if (j < cc->cnt - 1)
8698 bpf_log(log, " ");
8699 }
8700 bpf_log(log, "), ");
8701 }
8702 }
8703
print_cand_cache(struct bpf_verifier_log * log)8704 static void print_cand_cache(struct bpf_verifier_log *log)
8705 {
8706 mutex_lock(&cand_cache_mutex);
8707 bpf_log(log, "vmlinux_cand_cache:");
8708 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8709 bpf_log(log, "\nmodule_cand_cache:");
8710 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8711 bpf_log(log, "\n");
8712 mutex_unlock(&cand_cache_mutex);
8713 }
8714
hash_cands(struct bpf_cand_cache * cands)8715 static u32 hash_cands(struct bpf_cand_cache *cands)
8716 {
8717 return jhash(cands->name, cands->name_len, 0);
8718 }
8719
check_cand_cache(struct bpf_cand_cache * cands,struct bpf_cand_cache ** cache,int cache_size)8720 static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
8721 struct bpf_cand_cache **cache,
8722 int cache_size)
8723 {
8724 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
8725
8726 if (cc && cc->name_len == cands->name_len &&
8727 !strncmp(cc->name, cands->name, cands->name_len))
8728 return cc;
8729 return NULL;
8730 }
8731
sizeof_cands(int cnt)8732 static size_t sizeof_cands(int cnt)
8733 {
8734 return offsetof(struct bpf_cand_cache, cands[cnt]);
8735 }
8736
populate_cand_cache(struct bpf_cand_cache * cands,struct bpf_cand_cache ** cache,int cache_size)8737 static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
8738 struct bpf_cand_cache **cache,
8739 int cache_size)
8740 {
8741 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
8742
8743 if (*cc) {
8744 bpf_free_cands_from_cache(*cc);
8745 *cc = NULL;
8746 }
8747 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
8748 if (!new_cands) {
8749 bpf_free_cands(cands);
8750 return ERR_PTR(-ENOMEM);
8751 }
8752 /* strdup the name, since it will stay in cache.
8753 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
8754 */
8755 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
8756 bpf_free_cands(cands);
8757 if (!new_cands->name) {
8758 kfree(new_cands);
8759 return ERR_PTR(-ENOMEM);
8760 }
8761 *cc = new_cands;
8762 return new_cands;
8763 }
8764
8765 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
__purge_cand_cache(struct btf * btf,struct bpf_cand_cache ** cache,int cache_size)8766 static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
8767 int cache_size)
8768 {
8769 struct bpf_cand_cache *cc;
8770 int i, j;
8771
8772 for (i = 0; i < cache_size; i++) {
8773 cc = cache[i];
8774 if (!cc)
8775 continue;
8776 if (!btf) {
8777 /* when new module is loaded purge all of module_cand_cache,
8778 * since new module might have candidates with the name
8779 * that matches cached cands.
8780 */
8781 bpf_free_cands_from_cache(cc);
8782 cache[i] = NULL;
8783 continue;
8784 }
8785 /* when module is unloaded purge cache entries
8786 * that match module's btf
8787 */
8788 for (j = 0; j < cc->cnt; j++)
8789 if (cc->cands[j].btf == btf) {
8790 bpf_free_cands_from_cache(cc);
8791 cache[i] = NULL;
8792 break;
8793 }
8794 }
8795
8796 }
8797
purge_cand_cache(struct btf * btf)8798 static void purge_cand_cache(struct btf *btf)
8799 {
8800 mutex_lock(&cand_cache_mutex);
8801 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8802 mutex_unlock(&cand_cache_mutex);
8803 }
8804 #endif
8805
8806 static struct bpf_cand_cache *
bpf_core_add_cands(struct bpf_cand_cache * cands,const struct btf * targ_btf,int targ_start_id)8807 bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
8808 int targ_start_id)
8809 {
8810 struct bpf_cand_cache *new_cands;
8811 const struct btf_type *t;
8812 const char *targ_name;
8813 size_t targ_essent_len;
8814 int n, i;
8815
8816 n = btf_nr_types(targ_btf);
8817 for (i = targ_start_id; i < n; i++) {
8818 t = btf_type_by_id(targ_btf, i);
8819 if (btf_kind(t) != cands->kind)
8820 continue;
8821
8822 targ_name = btf_name_by_offset(targ_btf, t->name_off);
8823 if (!targ_name)
8824 continue;
8825
8826 /* the resched point is before strncmp to make sure that search
8827 * for non-existing name will have a chance to schedule().
8828 */
8829 cond_resched();
8830
8831 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
8832 continue;
8833
8834 targ_essent_len = bpf_core_essential_name_len(targ_name);
8835 if (targ_essent_len != cands->name_len)
8836 continue;
8837
8838 /* most of the time there is only one candidate for a given kind+name pair */
8839 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
8840 if (!new_cands) {
8841 bpf_free_cands(cands);
8842 return ERR_PTR(-ENOMEM);
8843 }
8844
8845 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
8846 bpf_free_cands(cands);
8847 cands = new_cands;
8848 cands->cands[cands->cnt].btf = targ_btf;
8849 cands->cands[cands->cnt].id = i;
8850 cands->cnt++;
8851 }
8852 return cands;
8853 }
8854
8855 static struct bpf_cand_cache *
bpf_core_find_cands(struct bpf_core_ctx * ctx,u32 local_type_id)8856 bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
8857 {
8858 struct bpf_cand_cache *cands, *cc, local_cand = {};
8859 const struct btf *local_btf = ctx->btf;
8860 const struct btf_type *local_type;
8861 const struct btf *main_btf;
8862 size_t local_essent_len;
8863 struct btf *mod_btf;
8864 const char *name;
8865 int id;
8866
8867 main_btf = bpf_get_btf_vmlinux();
8868 if (IS_ERR(main_btf))
8869 return ERR_CAST(main_btf);
8870 if (!main_btf)
8871 return ERR_PTR(-EINVAL);
8872
8873 local_type = btf_type_by_id(local_btf, local_type_id);
8874 if (!local_type)
8875 return ERR_PTR(-EINVAL);
8876
8877 name = btf_name_by_offset(local_btf, local_type->name_off);
8878 if (str_is_empty(name))
8879 return ERR_PTR(-EINVAL);
8880 local_essent_len = bpf_core_essential_name_len(name);
8881
8882 cands = &local_cand;
8883 cands->name = name;
8884 cands->kind = btf_kind(local_type);
8885 cands->name_len = local_essent_len;
8886
8887 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8888 /* cands is a pointer to stack here */
8889 if (cc) {
8890 if (cc->cnt)
8891 return cc;
8892 goto check_modules;
8893 }
8894
8895 /* Attempt to find target candidates in vmlinux BTF first */
8896 cands = bpf_core_add_cands(cands, main_btf, 1);
8897 if (IS_ERR(cands))
8898 return ERR_CAST(cands);
8899
8900 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
8901
8902 /* populate cache even when cands->cnt == 0 */
8903 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8904 if (IS_ERR(cc))
8905 return ERR_CAST(cc);
8906
8907 /* if vmlinux BTF has any candidate, don't go for module BTFs */
8908 if (cc->cnt)
8909 return cc;
8910
8911 check_modules:
8912 /* cands is a pointer to stack here and cands->cnt == 0 */
8913 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8914 if (cc)
8915 /* if cache has it return it even if cc->cnt == 0 */
8916 return cc;
8917
8918 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
8919 spin_lock_bh(&btf_idr_lock);
8920 idr_for_each_entry(&btf_idr, mod_btf, id) {
8921 if (!btf_is_module(mod_btf))
8922 continue;
8923 /* linear search could be slow hence unlock/lock
8924 * the IDR to avoiding holding it for too long
8925 */
8926 btf_get(mod_btf);
8927 spin_unlock_bh(&btf_idr_lock);
8928 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
8929 btf_put(mod_btf);
8930 if (IS_ERR(cands))
8931 return ERR_CAST(cands);
8932 spin_lock_bh(&btf_idr_lock);
8933 }
8934 spin_unlock_bh(&btf_idr_lock);
8935 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
8936 * or pointer to stack if cands->cnd == 0.
8937 * Copy it into the cache even when cands->cnt == 0 and
8938 * return the result.
8939 */
8940 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8941 }
8942
bpf_core_apply(struct bpf_core_ctx * ctx,const struct bpf_core_relo * relo,int relo_idx,void * insn)8943 int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
8944 int relo_idx, void *insn)
8945 {
8946 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
8947 struct bpf_core_cand_list cands = {};
8948 struct bpf_core_relo_res targ_res;
8949 struct bpf_core_spec *specs;
8950 const struct btf_type *type;
8951 int err;
8952
8953 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
8954 * into arrays of btf_ids of struct fields and array indices.
8955 */
8956 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
8957 if (!specs)
8958 return -ENOMEM;
8959
8960 type = btf_type_by_id(ctx->btf, relo->type_id);
8961 if (!type) {
8962 bpf_log(ctx->log, "relo #%u: bad type id %u\n",
8963 relo_idx, relo->type_id);
8964 return -EINVAL;
8965 }
8966
8967 if (need_cands) {
8968 struct bpf_cand_cache *cc;
8969 int i;
8970
8971 mutex_lock(&cand_cache_mutex);
8972 cc = bpf_core_find_cands(ctx, relo->type_id);
8973 if (IS_ERR(cc)) {
8974 bpf_log(ctx->log, "target candidate search failed for %d\n",
8975 relo->type_id);
8976 err = PTR_ERR(cc);
8977 goto out;
8978 }
8979 if (cc->cnt) {
8980 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
8981 if (!cands.cands) {
8982 err = -ENOMEM;
8983 goto out;
8984 }
8985 }
8986 for (i = 0; i < cc->cnt; i++) {
8987 bpf_log(ctx->log,
8988 "CO-RE relocating %s %s: found target candidate [%d]\n",
8989 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
8990 cands.cands[i].btf = cc->cands[i].btf;
8991 cands.cands[i].id = cc->cands[i].id;
8992 }
8993 cands.len = cc->cnt;
8994 /* cand_cache_mutex needs to span the cache lookup and
8995 * copy of btf pointer into bpf_core_cand_list,
8996 * since module can be unloaded while bpf_core_calc_relo_insn
8997 * is working with module's btf.
8998 */
8999 }
9000
9001 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
9002 &targ_res);
9003 if (err)
9004 goto out;
9005
9006 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
9007 &targ_res);
9008
9009 out:
9010 kfree(specs);
9011 if (need_cands) {
9012 kfree(cands.cands);
9013 mutex_unlock(&cand_cache_mutex);
9014 if (ctx->log->level & BPF_LOG_LEVEL2)
9015 print_cand_cache(ctx->log);
9016 }
9017 return err;
9018 }
9019
btf_nested_type_is_trusted(struct bpf_verifier_log * log,const struct bpf_reg_state * reg,const char * field_name,u32 btf_id,const char * suffix)9020 bool btf_nested_type_is_trusted(struct bpf_verifier_log *log,
9021 const struct bpf_reg_state *reg,
9022 const char *field_name, u32 btf_id, const char *suffix)
9023 {
9024 struct btf *btf = reg->btf;
9025 const struct btf_type *walk_type, *safe_type;
9026 const char *tname;
9027 char safe_tname[64];
9028 long ret, safe_id;
9029 const struct btf_member *member;
9030 u32 i;
9031
9032 walk_type = btf_type_by_id(btf, reg->btf_id);
9033 if (!walk_type)
9034 return false;
9035
9036 tname = btf_name_by_offset(btf, walk_type->name_off);
9037
9038 ret = snprintf(safe_tname, sizeof(safe_tname), "%s%s", tname, suffix);
9039 if (ret >= sizeof(safe_tname))
9040 return false;
9041
9042 safe_id = btf_find_by_name_kind(btf, safe_tname, BTF_INFO_KIND(walk_type->info));
9043 if (safe_id < 0)
9044 return false;
9045
9046 safe_type = btf_type_by_id(btf, safe_id);
9047 if (!safe_type)
9048 return false;
9049
9050 for_each_member(i, safe_type, member) {
9051 const char *m_name = __btf_name_by_offset(btf, member->name_off);
9052 const struct btf_type *mtype = btf_type_by_id(btf, member->type);
9053 u32 id;
9054
9055 if (!btf_type_is_ptr(mtype))
9056 continue;
9057
9058 btf_type_skip_modifiers(btf, mtype->type, &id);
9059 /* If we match on both type and name, the field is considered trusted. */
9060 if (btf_id == id && !strcmp(field_name, m_name))
9061 return true;
9062 }
9063
9064 return false;
9065 }
9066
btf_type_ids_nocast_alias(struct bpf_verifier_log * log,const struct btf * reg_btf,u32 reg_id,const struct btf * arg_btf,u32 arg_id)9067 bool btf_type_ids_nocast_alias(struct bpf_verifier_log *log,
9068 const struct btf *reg_btf, u32 reg_id,
9069 const struct btf *arg_btf, u32 arg_id)
9070 {
9071 const char *reg_name, *arg_name, *search_needle;
9072 const struct btf_type *reg_type, *arg_type;
9073 int reg_len, arg_len, cmp_len;
9074 size_t pattern_len = sizeof(NOCAST_ALIAS_SUFFIX) - sizeof(char);
9075
9076 reg_type = btf_type_by_id(reg_btf, reg_id);
9077 if (!reg_type)
9078 return false;
9079
9080 arg_type = btf_type_by_id(arg_btf, arg_id);
9081 if (!arg_type)
9082 return false;
9083
9084 reg_name = btf_name_by_offset(reg_btf, reg_type->name_off);
9085 arg_name = btf_name_by_offset(arg_btf, arg_type->name_off);
9086
9087 reg_len = strlen(reg_name);
9088 arg_len = strlen(arg_name);
9089
9090 /* Exactly one of the two type names may be suffixed with ___init, so
9091 * if the strings are the same size, they can't possibly be no-cast
9092 * aliases of one another. If you have two of the same type names, e.g.
9093 * they're both nf_conn___init, it would be improper to return true
9094 * because they are _not_ no-cast aliases, they are the same type.
9095 */
9096 if (reg_len == arg_len)
9097 return false;
9098
9099 /* Either of the two names must be the other name, suffixed with ___init. */
9100 if ((reg_len != arg_len + pattern_len) &&
9101 (arg_len != reg_len + pattern_len))
9102 return false;
9103
9104 if (reg_len < arg_len) {
9105 search_needle = strstr(arg_name, NOCAST_ALIAS_SUFFIX);
9106 cmp_len = reg_len;
9107 } else {
9108 search_needle = strstr(reg_name, NOCAST_ALIAS_SUFFIX);
9109 cmp_len = arg_len;
9110 }
9111
9112 if (!search_needle)
9113 return false;
9114
9115 /* ___init suffix must come at the end of the name */
9116 if (*(search_needle + pattern_len) != '\0')
9117 return false;
9118
9119 return !strncmp(reg_name, arg_name, cmp_len);
9120 }
9121
9122 #ifdef CONFIG_BPF_JIT
9123 static int
btf_add_struct_ops(struct btf * btf,struct bpf_struct_ops * st_ops,struct bpf_verifier_log * log)9124 btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops,
9125 struct bpf_verifier_log *log)
9126 {
9127 struct btf_struct_ops_tab *tab, *new_tab;
9128 int i, err;
9129
9130 tab = btf->struct_ops_tab;
9131 if (!tab) {
9132 tab = kzalloc(offsetof(struct btf_struct_ops_tab, ops[4]),
9133 GFP_KERNEL);
9134 if (!tab)
9135 return -ENOMEM;
9136 tab->capacity = 4;
9137 btf->struct_ops_tab = tab;
9138 }
9139
9140 for (i = 0; i < tab->cnt; i++)
9141 if (tab->ops[i].st_ops == st_ops)
9142 return -EEXIST;
9143
9144 if (tab->cnt == tab->capacity) {
9145 new_tab = krealloc(tab,
9146 offsetof(struct btf_struct_ops_tab,
9147 ops[tab->capacity * 2]),
9148 GFP_KERNEL);
9149 if (!new_tab)
9150 return -ENOMEM;
9151 tab = new_tab;
9152 tab->capacity *= 2;
9153 btf->struct_ops_tab = tab;
9154 }
9155
9156 tab->ops[btf->struct_ops_tab->cnt].st_ops = st_ops;
9157
9158 err = bpf_struct_ops_desc_init(&tab->ops[btf->struct_ops_tab->cnt], btf, log);
9159 if (err)
9160 return err;
9161
9162 btf->struct_ops_tab->cnt++;
9163
9164 return 0;
9165 }
9166
9167 const struct bpf_struct_ops_desc *
bpf_struct_ops_find_value(struct btf * btf,u32 value_id)9168 bpf_struct_ops_find_value(struct btf *btf, u32 value_id)
9169 {
9170 const struct bpf_struct_ops_desc *st_ops_list;
9171 unsigned int i;
9172 u32 cnt;
9173
9174 if (!value_id)
9175 return NULL;
9176 if (!btf->struct_ops_tab)
9177 return NULL;
9178
9179 cnt = btf->struct_ops_tab->cnt;
9180 st_ops_list = btf->struct_ops_tab->ops;
9181 for (i = 0; i < cnt; i++) {
9182 if (st_ops_list[i].value_id == value_id)
9183 return &st_ops_list[i];
9184 }
9185
9186 return NULL;
9187 }
9188
9189 const struct bpf_struct_ops_desc *
bpf_struct_ops_find(struct btf * btf,u32 type_id)9190 bpf_struct_ops_find(struct btf *btf, u32 type_id)
9191 {
9192 const struct bpf_struct_ops_desc *st_ops_list;
9193 unsigned int i;
9194 u32 cnt;
9195
9196 if (!type_id)
9197 return NULL;
9198 if (!btf->struct_ops_tab)
9199 return NULL;
9200
9201 cnt = btf->struct_ops_tab->cnt;
9202 st_ops_list = btf->struct_ops_tab->ops;
9203 for (i = 0; i < cnt; i++) {
9204 if (st_ops_list[i].type_id == type_id)
9205 return &st_ops_list[i];
9206 }
9207
9208 return NULL;
9209 }
9210
__register_bpf_struct_ops(struct bpf_struct_ops * st_ops)9211 int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops)
9212 {
9213 struct bpf_verifier_log *log;
9214 struct btf *btf;
9215 int err = 0;
9216
9217 btf = btf_get_module_btf(st_ops->owner);
9218 if (!btf)
9219 return check_btf_kconfigs(st_ops->owner, "struct_ops");
9220 if (IS_ERR(btf))
9221 return PTR_ERR(btf);
9222
9223 log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN);
9224 if (!log) {
9225 err = -ENOMEM;
9226 goto errout;
9227 }
9228
9229 log->level = BPF_LOG_KERNEL;
9230
9231 err = btf_add_struct_ops(btf, st_ops, log);
9232
9233 errout:
9234 kfree(log);
9235 btf_put(btf);
9236
9237 return err;
9238 }
9239 EXPORT_SYMBOL_GPL(__register_bpf_struct_ops);
9240 #endif
9241
btf_param_match_suffix(const struct btf * btf,const struct btf_param * arg,const char * suffix)9242 bool btf_param_match_suffix(const struct btf *btf,
9243 const struct btf_param *arg,
9244 const char *suffix)
9245 {
9246 int suffix_len = strlen(suffix), len;
9247 const char *param_name;
9248
9249 /* In the future, this can be ported to use BTF tagging */
9250 param_name = btf_name_by_offset(btf, arg->name_off);
9251 if (str_is_empty(param_name))
9252 return false;
9253 len = strlen(param_name);
9254 if (len <= suffix_len)
9255 return false;
9256 param_name += len - suffix_len;
9257 return !strncmp(param_name, suffix, suffix_len);
9258 }
9259