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1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* Copyright (c) 2018 Facebook */ | |
3 | ||
4 | #include <uapi/linux/btf.h> | |
5 | #include <uapi/linux/types.h> | |
b00b8dae | 6 | #include <linux/seq_file.h> |
69b693f0 MKL |
7 | #include <linux/compiler.h> |
8 | #include <linux/errno.h> | |
9 | #include <linux/slab.h> | |
f56a653c MKL |
10 | #include <linux/anon_inodes.h> |
11 | #include <linux/file.h> | |
69b693f0 MKL |
12 | #include <linux/uaccess.h> |
13 | #include <linux/kernel.h> | |
78958fca | 14 | #include <linux/idr.h> |
69b693f0 MKL |
15 | #include <linux/bpf_verifier.h> |
16 | #include <linux/btf.h> | |
17 | ||
18 | /* BTF (BPF Type Format) is the meta data format which describes | |
19 | * the data types of BPF program/map. Hence, it basically focus | |
20 | * on the C programming language which the modern BPF is primary | |
21 | * using. | |
22 | * | |
23 | * ELF Section: | |
24 | * ~~~~~~~~~~~ | |
25 | * The BTF data is stored under the ".BTF" ELF section | |
26 | * | |
27 | * struct btf_type: | |
28 | * ~~~~~~~~~~~~~~~ | |
29 | * Each 'struct btf_type' object describes a C data type. | |
30 | * Depending on the type it is describing, a 'struct btf_type' | |
31 | * object may be followed by more data. F.e. | |
32 | * To describe an array, 'struct btf_type' is followed by | |
33 | * 'struct btf_array'. | |
34 | * | |
35 | * 'struct btf_type' and any extra data following it are | |
36 | * 4 bytes aligned. | |
37 | * | |
38 | * Type section: | |
39 | * ~~~~~~~~~~~~~ | |
40 | * The BTF type section contains a list of 'struct btf_type' objects. | |
41 | * Each one describes a C type. Recall from the above section | |
42 | * that a 'struct btf_type' object could be immediately followed by extra | |
43 | * data in order to desribe some particular C types. | |
44 | * | |
45 | * type_id: | |
46 | * ~~~~~~~ | |
47 | * Each btf_type object is identified by a type_id. The type_id | |
48 | * is implicitly implied by the location of the btf_type object in | |
49 | * the BTF type section. The first one has type_id 1. The second | |
50 | * one has type_id 2...etc. Hence, an earlier btf_type has | |
51 | * a smaller type_id. | |
52 | * | |
53 | * A btf_type object may refer to another btf_type object by using | |
54 | * type_id (i.e. the "type" in the "struct btf_type"). | |
55 | * | |
56 | * NOTE that we cannot assume any reference-order. | |
57 | * A btf_type object can refer to an earlier btf_type object | |
58 | * but it can also refer to a later btf_type object. | |
59 | * | |
60 | * For example, to describe "const void *". A btf_type | |
61 | * object describing "const" may refer to another btf_type | |
62 | * object describing "void *". This type-reference is done | |
63 | * by specifying type_id: | |
64 | * | |
65 | * [1] CONST (anon) type_id=2 | |
66 | * [2] PTR (anon) type_id=0 | |
67 | * | |
68 | * The above is the btf_verifier debug log: | |
69 | * - Each line started with "[?]" is a btf_type object | |
70 | * - [?] is the type_id of the btf_type object. | |
71 | * - CONST/PTR is the BTF_KIND_XXX | |
72 | * - "(anon)" is the name of the type. It just | |
73 | * happens that CONST and PTR has no name. | |
74 | * - type_id=XXX is the 'u32 type' in btf_type | |
75 | * | |
76 | * NOTE: "void" has type_id 0 | |
77 | * | |
78 | * String section: | |
79 | * ~~~~~~~~~~~~~~ | |
80 | * The BTF string section contains the names used by the type section. | |
81 | * Each string is referred by an "offset" from the beginning of the | |
82 | * string section. | |
83 | * | |
84 | * Each string is '\0' terminated. | |
85 | * | |
86 | * The first character in the string section must be '\0' | |
87 | * which is used to mean 'anonymous'. Some btf_type may not | |
88 | * have a name. | |
89 | */ | |
90 | ||
91 | /* BTF verification: | |
92 | * | |
93 | * To verify BTF data, two passes are needed. | |
94 | * | |
95 | * Pass #1 | |
96 | * ~~~~~~~ | |
97 | * The first pass is to collect all btf_type objects to | |
98 | * an array: "btf->types". | |
99 | * | |
100 | * Depending on the C type that a btf_type is describing, | |
101 | * a btf_type may be followed by extra data. We don't know | |
102 | * how many btf_type is there, and more importantly we don't | |
103 | * know where each btf_type is located in the type section. | |
104 | * | |
105 | * Without knowing the location of each type_id, most verifications | |
106 | * cannot be done. e.g. an earlier btf_type may refer to a later | |
107 | * btf_type (recall the "const void *" above), so we cannot | |
108 | * check this type-reference in the first pass. | |
109 | * | |
110 | * In the first pass, it still does some verifications (e.g. | |
111 | * checking the name is a valid offset to the string section). | |
eb3f595d MKL |
112 | * |
113 | * Pass #2 | |
114 | * ~~~~~~~ | |
115 | * The main focus is to resolve a btf_type that is referring | |
116 | * to another type. | |
117 | * | |
118 | * We have to ensure the referring type: | |
119 | * 1) does exist in the BTF (i.e. in btf->types[]) | |
120 | * 2) does not cause a loop: | |
121 | * struct A { | |
122 | * struct B b; | |
123 | * }; | |
124 | * | |
125 | * struct B { | |
126 | * struct A a; | |
127 | * }; | |
128 | * | |
129 | * btf_type_needs_resolve() decides if a btf_type needs | |
130 | * to be resolved. | |
131 | * | |
132 | * The needs_resolve type implements the "resolve()" ops which | |
133 | * essentially does a DFS and detects backedge. | |
134 | * | |
135 | * During resolve (or DFS), different C types have different | |
136 | * "RESOLVED" conditions. | |
137 | * | |
138 | * When resolving a BTF_KIND_STRUCT, we need to resolve all its | |
139 | * members because a member is always referring to another | |
140 | * type. A struct's member can be treated as "RESOLVED" if | |
141 | * it is referring to a BTF_KIND_PTR. Otherwise, the | |
142 | * following valid C struct would be rejected: | |
143 | * | |
144 | * struct A { | |
145 | * int m; | |
146 | * struct A *a; | |
147 | * }; | |
148 | * | |
149 | * When resolving a BTF_KIND_PTR, it needs to keep resolving if | |
150 | * it is referring to another BTF_KIND_PTR. Otherwise, we cannot | |
151 | * detect a pointer loop, e.g.: | |
152 | * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR + | |
153 | * ^ | | |
154 | * +-----------------------------------------+ | |
155 | * | |
69b693f0 MKL |
156 | */ |
157 | ||
158 | #define BITS_PER_U64 (sizeof(u64) * BITS_PER_BYTE) | |
159 | #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1) | |
160 | #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK) | |
161 | #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3) | |
162 | #define BITS_ROUNDUP_BYTES(bits) \ | |
163 | (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits)) | |
164 | ||
165 | /* 16MB for 64k structs and each has 16 members and | |
166 | * a few MB spaces for the string section. | |
167 | * The hard limit is S32_MAX. | |
168 | */ | |
169 | #define BTF_MAX_SIZE (16 * 1024 * 1024) | |
170 | /* 64k. We can raise it later. The hard limit is S32_MAX. */ | |
171 | #define BTF_MAX_NR_TYPES 65535 | |
172 | ||
173 | #define for_each_member(i, struct_type, member) \ | |
174 | for (i = 0, member = btf_type_member(struct_type); \ | |
175 | i < btf_type_vlen(struct_type); \ | |
176 | i++, member++) | |
177 | ||
eb3f595d MKL |
178 | #define for_each_member_from(i, from, struct_type, member) \ |
179 | for (i = from, member = btf_type_member(struct_type) + from; \ | |
180 | i < btf_type_vlen(struct_type); \ | |
181 | i++, member++) | |
182 | ||
78958fca MKL |
183 | static DEFINE_IDR(btf_idr); |
184 | static DEFINE_SPINLOCK(btf_idr_lock); | |
185 | ||
69b693f0 MKL |
186 | struct btf { |
187 | union { | |
188 | struct btf_header *hdr; | |
189 | void *data; | |
190 | }; | |
191 | struct btf_type **types; | |
eb3f595d MKL |
192 | u32 *resolved_ids; |
193 | u32 *resolved_sizes; | |
69b693f0 MKL |
194 | const char *strings; |
195 | void *nohdr_data; | |
196 | u32 nr_types; | |
197 | u32 types_size; | |
198 | u32 data_size; | |
f56a653c | 199 | refcount_t refcnt; |
78958fca MKL |
200 | u32 id; |
201 | struct rcu_head rcu; | |
69b693f0 MKL |
202 | }; |
203 | ||
eb3f595d MKL |
204 | enum verifier_phase { |
205 | CHECK_META, | |
206 | CHECK_TYPE, | |
207 | }; | |
208 | ||
209 | struct resolve_vertex { | |
210 | const struct btf_type *t; | |
211 | u32 type_id; | |
212 | u16 next_member; | |
213 | }; | |
214 | ||
215 | enum visit_state { | |
216 | NOT_VISITED, | |
217 | VISITED, | |
218 | RESOLVED, | |
219 | }; | |
220 | ||
221 | enum resolve_mode { | |
222 | RESOLVE_TBD, /* To Be Determined */ | |
223 | RESOLVE_PTR, /* Resolving for Pointer */ | |
224 | RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union | |
225 | * or array | |
226 | */ | |
227 | }; | |
228 | ||
229 | #define MAX_RESOLVE_DEPTH 32 | |
230 | ||
69b693f0 MKL |
231 | struct btf_verifier_env { |
232 | struct btf *btf; | |
eb3f595d MKL |
233 | u8 *visit_states; |
234 | struct resolve_vertex stack[MAX_RESOLVE_DEPTH]; | |
69b693f0 MKL |
235 | struct bpf_verifier_log log; |
236 | u32 log_type_id; | |
eb3f595d MKL |
237 | u32 top_stack; |
238 | enum verifier_phase phase; | |
239 | enum resolve_mode resolve_mode; | |
69b693f0 MKL |
240 | }; |
241 | ||
242 | static const char * const btf_kind_str[NR_BTF_KINDS] = { | |
243 | [BTF_KIND_UNKN] = "UNKNOWN", | |
244 | [BTF_KIND_INT] = "INT", | |
245 | [BTF_KIND_PTR] = "PTR", | |
246 | [BTF_KIND_ARRAY] = "ARRAY", | |
247 | [BTF_KIND_STRUCT] = "STRUCT", | |
248 | [BTF_KIND_UNION] = "UNION", | |
249 | [BTF_KIND_ENUM] = "ENUM", | |
250 | [BTF_KIND_FWD] = "FWD", | |
251 | [BTF_KIND_TYPEDEF] = "TYPEDEF", | |
252 | [BTF_KIND_VOLATILE] = "VOLATILE", | |
253 | [BTF_KIND_CONST] = "CONST", | |
254 | [BTF_KIND_RESTRICT] = "RESTRICT", | |
255 | }; | |
256 | ||
257 | struct btf_kind_operations { | |
258 | s32 (*check_meta)(struct btf_verifier_env *env, | |
259 | const struct btf_type *t, | |
260 | u32 meta_left); | |
eb3f595d MKL |
261 | int (*resolve)(struct btf_verifier_env *env, |
262 | const struct resolve_vertex *v); | |
179cde8c MKL |
263 | int (*check_member)(struct btf_verifier_env *env, |
264 | const struct btf_type *struct_type, | |
265 | const struct btf_member *member, | |
266 | const struct btf_type *member_type); | |
69b693f0 MKL |
267 | void (*log_details)(struct btf_verifier_env *env, |
268 | const struct btf_type *t); | |
b00b8dae MKL |
269 | void (*seq_show)(const struct btf *btf, const struct btf_type *t, |
270 | u32 type_id, void *data, u8 bits_offsets, | |
271 | struct seq_file *m); | |
69b693f0 MKL |
272 | }; |
273 | ||
274 | static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS]; | |
275 | static struct btf_type btf_void; | |
276 | ||
eb3f595d MKL |
277 | static bool btf_type_is_modifier(const struct btf_type *t) |
278 | { | |
279 | /* Some of them is not strictly a C modifier | |
280 | * but they are grouped into the same bucket | |
281 | * for BTF concern: | |
282 | * A type (t) that refers to another | |
283 | * type through t->type AND its size cannot | |
284 | * be determined without following the t->type. | |
285 | * | |
286 | * ptr does not fall into this bucket | |
287 | * because its size is always sizeof(void *). | |
288 | */ | |
289 | switch (BTF_INFO_KIND(t->info)) { | |
290 | case BTF_KIND_TYPEDEF: | |
291 | case BTF_KIND_VOLATILE: | |
292 | case BTF_KIND_CONST: | |
293 | case BTF_KIND_RESTRICT: | |
294 | return true; | |
295 | } | |
296 | ||
297 | return false; | |
298 | } | |
299 | ||
300 | static bool btf_type_is_void(const struct btf_type *t) | |
301 | { | |
302 | /* void => no type and size info. | |
303 | * Hence, FWD is also treated as void. | |
304 | */ | |
305 | return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD; | |
306 | } | |
307 | ||
308 | static bool btf_type_is_void_or_null(const struct btf_type *t) | |
309 | { | |
310 | return !t || btf_type_is_void(t); | |
311 | } | |
312 | ||
313 | /* union is only a special case of struct: | |
314 | * all its offsetof(member) == 0 | |
315 | */ | |
316 | static bool btf_type_is_struct(const struct btf_type *t) | |
317 | { | |
318 | u8 kind = BTF_INFO_KIND(t->info); | |
319 | ||
320 | return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; | |
321 | } | |
322 | ||
323 | static bool btf_type_is_array(const struct btf_type *t) | |
324 | { | |
325 | return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY; | |
326 | } | |
327 | ||
328 | static bool btf_type_is_ptr(const struct btf_type *t) | |
329 | { | |
330 | return BTF_INFO_KIND(t->info) == BTF_KIND_PTR; | |
331 | } | |
332 | ||
333 | static bool btf_type_is_int(const struct btf_type *t) | |
334 | { | |
335 | return BTF_INFO_KIND(t->info) == BTF_KIND_INT; | |
336 | } | |
337 | ||
338 | /* What types need to be resolved? | |
339 | * | |
340 | * btf_type_is_modifier() is an obvious one. | |
341 | * | |
342 | * btf_type_is_struct() because its member refers to | |
343 | * another type (through member->type). | |
344 | ||
345 | * btf_type_is_array() because its element (array->type) | |
346 | * refers to another type. Array can be thought of a | |
347 | * special case of struct while array just has the same | |
348 | * member-type repeated by array->nelems of times. | |
349 | */ | |
350 | static bool btf_type_needs_resolve(const struct btf_type *t) | |
351 | { | |
352 | return btf_type_is_modifier(t) || | |
353 | btf_type_is_ptr(t) || | |
354 | btf_type_is_struct(t) || | |
355 | btf_type_is_array(t); | |
356 | } | |
357 | ||
358 | /* t->size can be used */ | |
359 | static bool btf_type_has_size(const struct btf_type *t) | |
360 | { | |
361 | switch (BTF_INFO_KIND(t->info)) { | |
362 | case BTF_KIND_INT: | |
363 | case BTF_KIND_STRUCT: | |
364 | case BTF_KIND_UNION: | |
365 | case BTF_KIND_ENUM: | |
366 | return true; | |
367 | } | |
368 | ||
369 | return false; | |
370 | } | |
371 | ||
69b693f0 MKL |
372 | static const char *btf_int_encoding_str(u8 encoding) |
373 | { | |
374 | if (encoding == 0) | |
375 | return "(none)"; | |
376 | else if (encoding == BTF_INT_SIGNED) | |
377 | return "SIGNED"; | |
378 | else if (encoding == BTF_INT_CHAR) | |
379 | return "CHAR"; | |
380 | else if (encoding == BTF_INT_BOOL) | |
381 | return "BOOL"; | |
382 | else if (encoding == BTF_INT_VARARGS) | |
383 | return "VARARGS"; | |
384 | else | |
385 | return "UNKN"; | |
386 | } | |
387 | ||
388 | static u16 btf_type_vlen(const struct btf_type *t) | |
389 | { | |
390 | return BTF_INFO_VLEN(t->info); | |
391 | } | |
392 | ||
393 | static u32 btf_type_int(const struct btf_type *t) | |
394 | { | |
395 | return *(u32 *)(t + 1); | |
396 | } | |
397 | ||
398 | static const struct btf_array *btf_type_array(const struct btf_type *t) | |
399 | { | |
400 | return (const struct btf_array *)(t + 1); | |
401 | } | |
402 | ||
403 | static const struct btf_member *btf_type_member(const struct btf_type *t) | |
404 | { | |
405 | return (const struct btf_member *)(t + 1); | |
406 | } | |
407 | ||
408 | static const struct btf_enum *btf_type_enum(const struct btf_type *t) | |
409 | { | |
410 | return (const struct btf_enum *)(t + 1); | |
411 | } | |
412 | ||
413 | static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t) | |
414 | { | |
415 | return kind_ops[BTF_INFO_KIND(t->info)]; | |
416 | } | |
417 | ||
418 | static bool btf_name_offset_valid(const struct btf *btf, u32 offset) | |
419 | { | |
420 | return !BTF_STR_TBL_ELF_ID(offset) && | |
421 | BTF_STR_OFFSET(offset) < btf->hdr->str_len; | |
422 | } | |
423 | ||
424 | static const char *btf_name_by_offset(const struct btf *btf, u32 offset) | |
425 | { | |
426 | if (!BTF_STR_OFFSET(offset)) | |
427 | return "(anon)"; | |
428 | else if (BTF_STR_OFFSET(offset) < btf->hdr->str_len) | |
429 | return &btf->strings[BTF_STR_OFFSET(offset)]; | |
430 | else | |
431 | return "(invalid-name-offset)"; | |
432 | } | |
433 | ||
eb3f595d MKL |
434 | static const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) |
435 | { | |
436 | if (type_id > btf->nr_types) | |
437 | return NULL; | |
438 | ||
439 | return btf->types[type_id]; | |
440 | } | |
441 | ||
69b693f0 MKL |
442 | __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log, |
443 | const char *fmt, ...) | |
444 | { | |
445 | va_list args; | |
446 | ||
447 | va_start(args, fmt); | |
448 | bpf_verifier_vlog(log, fmt, args); | |
449 | va_end(args); | |
450 | } | |
451 | ||
452 | __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env, | |
453 | const char *fmt, ...) | |
454 | { | |
455 | struct bpf_verifier_log *log = &env->log; | |
456 | va_list args; | |
457 | ||
458 | if (!bpf_verifier_log_needed(log)) | |
459 | return; | |
460 | ||
461 | va_start(args, fmt); | |
462 | bpf_verifier_vlog(log, fmt, args); | |
463 | va_end(args); | |
464 | } | |
465 | ||
466 | __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env, | |
467 | const struct btf_type *t, | |
468 | bool log_details, | |
469 | const char *fmt, ...) | |
470 | { | |
471 | struct bpf_verifier_log *log = &env->log; | |
472 | u8 kind = BTF_INFO_KIND(t->info); | |
473 | struct btf *btf = env->btf; | |
474 | va_list args; | |
475 | ||
476 | if (!bpf_verifier_log_needed(log)) | |
477 | return; | |
478 | ||
479 | __btf_verifier_log(log, "[%u] %s %s%s", | |
480 | env->log_type_id, | |
481 | btf_kind_str[kind], | |
fbcf93eb | 482 | btf_name_by_offset(btf, t->name_off), |
69b693f0 MKL |
483 | log_details ? " " : ""); |
484 | ||
485 | if (log_details) | |
486 | btf_type_ops(t)->log_details(env, t); | |
487 | ||
488 | if (fmt && *fmt) { | |
489 | __btf_verifier_log(log, " "); | |
490 | va_start(args, fmt); | |
491 | bpf_verifier_vlog(log, fmt, args); | |
492 | va_end(args); | |
493 | } | |
494 | ||
495 | __btf_verifier_log(log, "\n"); | |
496 | } | |
497 | ||
498 | #define btf_verifier_log_type(env, t, ...) \ | |
499 | __btf_verifier_log_type((env), (t), true, __VA_ARGS__) | |
500 | #define btf_verifier_log_basic(env, t, ...) \ | |
501 | __btf_verifier_log_type((env), (t), false, __VA_ARGS__) | |
502 | ||
503 | __printf(4, 5) | |
504 | static void btf_verifier_log_member(struct btf_verifier_env *env, | |
505 | const struct btf_type *struct_type, | |
506 | const struct btf_member *member, | |
507 | const char *fmt, ...) | |
508 | { | |
509 | struct bpf_verifier_log *log = &env->log; | |
510 | struct btf *btf = env->btf; | |
511 | va_list args; | |
512 | ||
513 | if (!bpf_verifier_log_needed(log)) | |
514 | return; | |
515 | ||
eb3f595d MKL |
516 | /* The CHECK_META phase already did a btf dump. |
517 | * | |
518 | * If member is logged again, it must hit an error in | |
519 | * parsing this member. It is useful to print out which | |
520 | * struct this member belongs to. | |
521 | */ | |
522 | if (env->phase != CHECK_META) | |
523 | btf_verifier_log_type(env, struct_type, NULL); | |
524 | ||
69b693f0 | 525 | __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u", |
fbcf93eb | 526 | btf_name_by_offset(btf, member->name_off), |
69b693f0 MKL |
527 | member->type, member->offset); |
528 | ||
529 | if (fmt && *fmt) { | |
530 | __btf_verifier_log(log, " "); | |
531 | va_start(args, fmt); | |
532 | bpf_verifier_vlog(log, fmt, args); | |
533 | va_end(args); | |
534 | } | |
535 | ||
536 | __btf_verifier_log(log, "\n"); | |
537 | } | |
538 | ||
539 | static void btf_verifier_log_hdr(struct btf_verifier_env *env) | |
540 | { | |
541 | struct bpf_verifier_log *log = &env->log; | |
542 | const struct btf *btf = env->btf; | |
543 | const struct btf_header *hdr; | |
544 | ||
545 | if (!bpf_verifier_log_needed(log)) | |
546 | return; | |
547 | ||
548 | hdr = btf->hdr; | |
549 | __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic); | |
550 | __btf_verifier_log(log, "version: %u\n", hdr->version); | |
551 | __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags); | |
552 | __btf_verifier_log(log, "parent_label: %u\n", hdr->parent_label); | |
553 | __btf_verifier_log(log, "parent_name: %u\n", hdr->parent_name); | |
554 | __btf_verifier_log(log, "label_off: %u\n", hdr->label_off); | |
555 | __btf_verifier_log(log, "object_off: %u\n", hdr->object_off); | |
556 | __btf_verifier_log(log, "func_off: %u\n", hdr->func_off); | |
557 | __btf_verifier_log(log, "type_off: %u\n", hdr->type_off); | |
558 | __btf_verifier_log(log, "str_off: %u\n", hdr->str_off); | |
559 | __btf_verifier_log(log, "str_len: %u\n", hdr->str_len); | |
560 | __btf_verifier_log(log, "btf_total_size: %u\n", btf->data_size); | |
561 | } | |
562 | ||
563 | static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t) | |
564 | { | |
565 | struct btf *btf = env->btf; | |
566 | ||
567 | /* < 2 because +1 for btf_void which is always in btf->types[0]. | |
568 | * btf_void is not accounted in btf->nr_types because btf_void | |
569 | * does not come from the BTF file. | |
570 | */ | |
571 | if (btf->types_size - btf->nr_types < 2) { | |
572 | /* Expand 'types' array */ | |
573 | ||
574 | struct btf_type **new_types; | |
575 | u32 expand_by, new_size; | |
576 | ||
577 | if (btf->types_size == BTF_MAX_NR_TYPES) { | |
578 | btf_verifier_log(env, "Exceeded max num of types"); | |
579 | return -E2BIG; | |
580 | } | |
581 | ||
582 | expand_by = max_t(u32, btf->types_size >> 2, 16); | |
583 | new_size = min_t(u32, BTF_MAX_NR_TYPES, | |
584 | btf->types_size + expand_by); | |
585 | ||
586 | new_types = kvzalloc(new_size * sizeof(*new_types), | |
587 | GFP_KERNEL | __GFP_NOWARN); | |
588 | if (!new_types) | |
589 | return -ENOMEM; | |
590 | ||
591 | if (btf->nr_types == 0) | |
592 | new_types[0] = &btf_void; | |
593 | else | |
594 | memcpy(new_types, btf->types, | |
595 | sizeof(*btf->types) * (btf->nr_types + 1)); | |
596 | ||
597 | kvfree(btf->types); | |
598 | btf->types = new_types; | |
599 | btf->types_size = new_size; | |
600 | } | |
601 | ||
602 | btf->types[++(btf->nr_types)] = t; | |
603 | ||
604 | return 0; | |
605 | } | |
606 | ||
78958fca MKL |
607 | static int btf_alloc_id(struct btf *btf) |
608 | { | |
609 | int id; | |
610 | ||
611 | idr_preload(GFP_KERNEL); | |
612 | spin_lock_bh(&btf_idr_lock); | |
613 | id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC); | |
614 | if (id > 0) | |
615 | btf->id = id; | |
616 | spin_unlock_bh(&btf_idr_lock); | |
617 | idr_preload_end(); | |
618 | ||
619 | if (WARN_ON_ONCE(!id)) | |
620 | return -ENOSPC; | |
621 | ||
622 | return id > 0 ? 0 : id; | |
623 | } | |
624 | ||
625 | static void btf_free_id(struct btf *btf) | |
626 | { | |
627 | unsigned long flags; | |
628 | ||
629 | /* | |
630 | * In map-in-map, calling map_delete_elem() on outer | |
631 | * map will call bpf_map_put on the inner map. | |
632 | * It will then eventually call btf_free_id() | |
633 | * on the inner map. Some of the map_delete_elem() | |
634 | * implementation may have irq disabled, so | |
635 | * we need to use the _irqsave() version instead | |
636 | * of the _bh() version. | |
637 | */ | |
638 | spin_lock_irqsave(&btf_idr_lock, flags); | |
639 | idr_remove(&btf_idr, btf->id); | |
640 | spin_unlock_irqrestore(&btf_idr_lock, flags); | |
641 | } | |
642 | ||
69b693f0 MKL |
643 | static void btf_free(struct btf *btf) |
644 | { | |
645 | kvfree(btf->types); | |
eb3f595d MKL |
646 | kvfree(btf->resolved_sizes); |
647 | kvfree(btf->resolved_ids); | |
69b693f0 MKL |
648 | kvfree(btf->data); |
649 | kfree(btf); | |
650 | } | |
651 | ||
78958fca | 652 | static void btf_free_rcu(struct rcu_head *rcu) |
f56a653c | 653 | { |
78958fca MKL |
654 | struct btf *btf = container_of(rcu, struct btf, rcu); |
655 | ||
656 | btf_free(btf); | |
f56a653c MKL |
657 | } |
658 | ||
659 | void btf_put(struct btf *btf) | |
660 | { | |
78958fca MKL |
661 | if (btf && refcount_dec_and_test(&btf->refcnt)) { |
662 | btf_free_id(btf); | |
663 | call_rcu(&btf->rcu, btf_free_rcu); | |
664 | } | |
f56a653c MKL |
665 | } |
666 | ||
eb3f595d MKL |
667 | static int env_resolve_init(struct btf_verifier_env *env) |
668 | { | |
669 | struct btf *btf = env->btf; | |
670 | u32 nr_types = btf->nr_types; | |
671 | u32 *resolved_sizes = NULL; | |
672 | u32 *resolved_ids = NULL; | |
673 | u8 *visit_states = NULL; | |
674 | ||
675 | /* +1 for btf_void */ | |
676 | resolved_sizes = kvzalloc((nr_types + 1) * sizeof(*resolved_sizes), | |
677 | GFP_KERNEL | __GFP_NOWARN); | |
678 | if (!resolved_sizes) | |
679 | goto nomem; | |
680 | ||
681 | resolved_ids = kvzalloc((nr_types + 1) * sizeof(*resolved_ids), | |
682 | GFP_KERNEL | __GFP_NOWARN); | |
683 | if (!resolved_ids) | |
684 | goto nomem; | |
685 | ||
686 | visit_states = kvzalloc((nr_types + 1) * sizeof(*visit_states), | |
687 | GFP_KERNEL | __GFP_NOWARN); | |
688 | if (!visit_states) | |
689 | goto nomem; | |
690 | ||
691 | btf->resolved_sizes = resolved_sizes; | |
692 | btf->resolved_ids = resolved_ids; | |
693 | env->visit_states = visit_states; | |
694 | ||
695 | return 0; | |
696 | ||
697 | nomem: | |
698 | kvfree(resolved_sizes); | |
699 | kvfree(resolved_ids); | |
700 | kvfree(visit_states); | |
701 | return -ENOMEM; | |
702 | } | |
703 | ||
69b693f0 MKL |
704 | static void btf_verifier_env_free(struct btf_verifier_env *env) |
705 | { | |
eb3f595d | 706 | kvfree(env->visit_states); |
69b693f0 MKL |
707 | kfree(env); |
708 | } | |
709 | ||
eb3f595d MKL |
710 | static bool env_type_is_resolve_sink(const struct btf_verifier_env *env, |
711 | const struct btf_type *next_type) | |
712 | { | |
713 | switch (env->resolve_mode) { | |
714 | case RESOLVE_TBD: | |
715 | /* int, enum or void is a sink */ | |
716 | return !btf_type_needs_resolve(next_type); | |
717 | case RESOLVE_PTR: | |
718 | /* int, enum, void, struct or array is a sink for ptr */ | |
719 | return !btf_type_is_modifier(next_type) && | |
720 | !btf_type_is_ptr(next_type); | |
721 | case RESOLVE_STRUCT_OR_ARRAY: | |
722 | /* int, enum, void or ptr is a sink for struct and array */ | |
723 | return !btf_type_is_modifier(next_type) && | |
724 | !btf_type_is_array(next_type) && | |
725 | !btf_type_is_struct(next_type); | |
726 | default: | |
727 | BUG_ON(1); | |
728 | } | |
729 | } | |
730 | ||
731 | static bool env_type_is_resolved(const struct btf_verifier_env *env, | |
732 | u32 type_id) | |
733 | { | |
734 | return env->visit_states[type_id] == RESOLVED; | |
735 | } | |
736 | ||
737 | static int env_stack_push(struct btf_verifier_env *env, | |
738 | const struct btf_type *t, u32 type_id) | |
739 | { | |
740 | struct resolve_vertex *v; | |
741 | ||
742 | if (env->top_stack == MAX_RESOLVE_DEPTH) | |
743 | return -E2BIG; | |
744 | ||
745 | if (env->visit_states[type_id] != NOT_VISITED) | |
746 | return -EEXIST; | |
747 | ||
748 | env->visit_states[type_id] = VISITED; | |
749 | ||
750 | v = &env->stack[env->top_stack++]; | |
751 | v->t = t; | |
752 | v->type_id = type_id; | |
753 | v->next_member = 0; | |
754 | ||
755 | if (env->resolve_mode == RESOLVE_TBD) { | |
756 | if (btf_type_is_ptr(t)) | |
757 | env->resolve_mode = RESOLVE_PTR; | |
758 | else if (btf_type_is_struct(t) || btf_type_is_array(t)) | |
759 | env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY; | |
760 | } | |
761 | ||
762 | return 0; | |
763 | } | |
764 | ||
765 | static void env_stack_set_next_member(struct btf_verifier_env *env, | |
766 | u16 next_member) | |
767 | { | |
768 | env->stack[env->top_stack - 1].next_member = next_member; | |
769 | } | |
770 | ||
771 | static void env_stack_pop_resolved(struct btf_verifier_env *env, | |
772 | u32 resolved_type_id, | |
773 | u32 resolved_size) | |
774 | { | |
775 | u32 type_id = env->stack[--(env->top_stack)].type_id; | |
776 | struct btf *btf = env->btf; | |
777 | ||
778 | btf->resolved_sizes[type_id] = resolved_size; | |
779 | btf->resolved_ids[type_id] = resolved_type_id; | |
780 | env->visit_states[type_id] = RESOLVED; | |
781 | } | |
782 | ||
783 | static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env) | |
784 | { | |
785 | return env->top_stack ? &env->stack[env->top_stack - 1] : NULL; | |
786 | } | |
787 | ||
788 | /* The input param "type_id" must point to a needs_resolve type */ | |
789 | static const struct btf_type *btf_type_id_resolve(const struct btf *btf, | |
790 | u32 *type_id) | |
791 | { | |
792 | *type_id = btf->resolved_ids[*type_id]; | |
793 | return btf_type_by_id(btf, *type_id); | |
794 | } | |
795 | ||
796 | const struct btf_type *btf_type_id_size(const struct btf *btf, | |
797 | u32 *type_id, u32 *ret_size) | |
798 | { | |
799 | const struct btf_type *size_type; | |
800 | u32 size_type_id = *type_id; | |
801 | u32 size = 0; | |
802 | ||
803 | size_type = btf_type_by_id(btf, size_type_id); | |
804 | if (btf_type_is_void_or_null(size_type)) | |
805 | return NULL; | |
806 | ||
807 | if (btf_type_has_size(size_type)) { | |
808 | size = size_type->size; | |
809 | } else if (btf_type_is_array(size_type)) { | |
810 | size = btf->resolved_sizes[size_type_id]; | |
811 | } else if (btf_type_is_ptr(size_type)) { | |
812 | size = sizeof(void *); | |
813 | } else { | |
814 | if (WARN_ON_ONCE(!btf_type_is_modifier(size_type))) | |
815 | return NULL; | |
816 | ||
817 | size = btf->resolved_sizes[size_type_id]; | |
818 | size_type_id = btf->resolved_ids[size_type_id]; | |
819 | size_type = btf_type_by_id(btf, size_type_id); | |
820 | if (btf_type_is_void(size_type)) | |
821 | return NULL; | |
822 | } | |
823 | ||
824 | *type_id = size_type_id; | |
825 | if (ret_size) | |
826 | *ret_size = size; | |
827 | ||
828 | return size_type; | |
829 | } | |
830 | ||
179cde8c MKL |
831 | static int btf_df_check_member(struct btf_verifier_env *env, |
832 | const struct btf_type *struct_type, | |
833 | const struct btf_member *member, | |
834 | const struct btf_type *member_type) | |
835 | { | |
836 | btf_verifier_log_basic(env, struct_type, | |
837 | "Unsupported check_member"); | |
838 | return -EINVAL; | |
839 | } | |
840 | ||
eb3f595d MKL |
841 | static int btf_df_resolve(struct btf_verifier_env *env, |
842 | const struct resolve_vertex *v) | |
843 | { | |
844 | btf_verifier_log_basic(env, v->t, "Unsupported resolve"); | |
845 | return -EINVAL; | |
846 | } | |
847 | ||
b00b8dae MKL |
848 | static void btf_df_seq_show(const struct btf *btf, const struct btf_type *t, |
849 | u32 type_id, void *data, u8 bits_offsets, | |
850 | struct seq_file *m) | |
851 | { | |
852 | seq_printf(m, "<unsupported kind:%u>", BTF_INFO_KIND(t->info)); | |
853 | } | |
854 | ||
179cde8c MKL |
855 | static int btf_int_check_member(struct btf_verifier_env *env, |
856 | const struct btf_type *struct_type, | |
857 | const struct btf_member *member, | |
858 | const struct btf_type *member_type) | |
859 | { | |
860 | u32 int_data = btf_type_int(member_type); | |
861 | u32 struct_bits_off = member->offset; | |
862 | u32 struct_size = struct_type->size; | |
863 | u32 nr_copy_bits; | |
864 | u32 bytes_offset; | |
865 | ||
866 | if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) { | |
867 | btf_verifier_log_member(env, struct_type, member, | |
868 | "bits_offset exceeds U32_MAX"); | |
869 | return -EINVAL; | |
870 | } | |
871 | ||
872 | struct_bits_off += BTF_INT_OFFSET(int_data); | |
873 | bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); | |
874 | nr_copy_bits = BTF_INT_BITS(int_data) + | |
875 | BITS_PER_BYTE_MASKED(struct_bits_off); | |
876 | ||
877 | if (nr_copy_bits > BITS_PER_U64) { | |
878 | btf_verifier_log_member(env, struct_type, member, | |
879 | "nr_copy_bits exceeds 64"); | |
880 | return -EINVAL; | |
881 | } | |
882 | ||
883 | if (struct_size < bytes_offset || | |
884 | struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) { | |
885 | btf_verifier_log_member(env, struct_type, member, | |
886 | "Member exceeds struct_size"); | |
887 | return -EINVAL; | |
888 | } | |
889 | ||
890 | return 0; | |
891 | } | |
892 | ||
69b693f0 MKL |
893 | static s32 btf_int_check_meta(struct btf_verifier_env *env, |
894 | const struct btf_type *t, | |
895 | u32 meta_left) | |
896 | { | |
897 | u32 int_data, nr_bits, meta_needed = sizeof(int_data); | |
898 | u16 encoding; | |
899 | ||
900 | if (meta_left < meta_needed) { | |
901 | btf_verifier_log_basic(env, t, | |
902 | "meta_left:%u meta_needed:%u", | |
903 | meta_left, meta_needed); | |
904 | return -EINVAL; | |
905 | } | |
906 | ||
907 | if (btf_type_vlen(t)) { | |
908 | btf_verifier_log_type(env, t, "vlen != 0"); | |
909 | return -EINVAL; | |
910 | } | |
911 | ||
912 | int_data = btf_type_int(t); | |
913 | nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data); | |
914 | ||
915 | if (nr_bits > BITS_PER_U64) { | |
916 | btf_verifier_log_type(env, t, "nr_bits exceeds %zu", | |
917 | BITS_PER_U64); | |
918 | return -EINVAL; | |
919 | } | |
920 | ||
921 | if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) { | |
922 | btf_verifier_log_type(env, t, "nr_bits exceeds type_size"); | |
923 | return -EINVAL; | |
924 | } | |
925 | ||
926 | encoding = BTF_INT_ENCODING(int_data); | |
927 | if (encoding && | |
928 | encoding != BTF_INT_SIGNED && | |
929 | encoding != BTF_INT_CHAR && | |
930 | encoding != BTF_INT_BOOL && | |
931 | encoding != BTF_INT_VARARGS) { | |
932 | btf_verifier_log_type(env, t, "Unsupported encoding"); | |
933 | return -ENOTSUPP; | |
934 | } | |
935 | ||
936 | btf_verifier_log_type(env, t, NULL); | |
937 | ||
938 | return meta_needed; | |
939 | } | |
940 | ||
941 | static void btf_int_log(struct btf_verifier_env *env, | |
942 | const struct btf_type *t) | |
943 | { | |
944 | int int_data = btf_type_int(t); | |
945 | ||
946 | btf_verifier_log(env, | |
947 | "size=%u bits_offset=%u nr_bits=%u encoding=%s", | |
948 | t->size, BTF_INT_OFFSET(int_data), | |
949 | BTF_INT_BITS(int_data), | |
950 | btf_int_encoding_str(BTF_INT_ENCODING(int_data))); | |
951 | } | |
952 | ||
b00b8dae MKL |
953 | static void btf_int_bits_seq_show(const struct btf *btf, |
954 | const struct btf_type *t, | |
955 | void *data, u8 bits_offset, | |
956 | struct seq_file *m) | |
957 | { | |
958 | u32 int_data = btf_type_int(t); | |
959 | u16 nr_bits = BTF_INT_BITS(int_data); | |
960 | u16 total_bits_offset; | |
961 | u16 nr_copy_bytes; | |
962 | u16 nr_copy_bits; | |
963 | u8 nr_upper_bits; | |
964 | union { | |
965 | u64 u64_num; | |
966 | u8 u8_nums[8]; | |
967 | } print_num; | |
968 | ||
969 | total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data); | |
970 | data += BITS_ROUNDDOWN_BYTES(total_bits_offset); | |
971 | bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset); | |
972 | nr_copy_bits = nr_bits + bits_offset; | |
973 | nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits); | |
974 | ||
975 | print_num.u64_num = 0; | |
976 | memcpy(&print_num.u64_num, data, nr_copy_bytes); | |
977 | ||
978 | /* Ditch the higher order bits */ | |
979 | nr_upper_bits = BITS_PER_BYTE_MASKED(nr_copy_bits); | |
980 | if (nr_upper_bits) { | |
981 | /* We need to mask out some bits of the upper byte. */ | |
982 | u8 mask = (1 << nr_upper_bits) - 1; | |
983 | ||
984 | print_num.u8_nums[nr_copy_bytes - 1] &= mask; | |
985 | } | |
986 | ||
987 | print_num.u64_num >>= bits_offset; | |
988 | ||
989 | seq_printf(m, "0x%llx", print_num.u64_num); | |
990 | } | |
991 | ||
992 | static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t, | |
993 | u32 type_id, void *data, u8 bits_offset, | |
994 | struct seq_file *m) | |
995 | { | |
996 | u32 int_data = btf_type_int(t); | |
997 | u8 encoding = BTF_INT_ENCODING(int_data); | |
998 | bool sign = encoding & BTF_INT_SIGNED; | |
999 | u32 nr_bits = BTF_INT_BITS(int_data); | |
1000 | ||
1001 | if (bits_offset || BTF_INT_OFFSET(int_data) || | |
1002 | BITS_PER_BYTE_MASKED(nr_bits)) { | |
1003 | btf_int_bits_seq_show(btf, t, data, bits_offset, m); | |
1004 | return; | |
1005 | } | |
1006 | ||
1007 | switch (nr_bits) { | |
1008 | case 64: | |
1009 | if (sign) | |
1010 | seq_printf(m, "%lld", *(s64 *)data); | |
1011 | else | |
1012 | seq_printf(m, "%llu", *(u64 *)data); | |
1013 | break; | |
1014 | case 32: | |
1015 | if (sign) | |
1016 | seq_printf(m, "%d", *(s32 *)data); | |
1017 | else | |
1018 | seq_printf(m, "%u", *(u32 *)data); | |
1019 | break; | |
1020 | case 16: | |
1021 | if (sign) | |
1022 | seq_printf(m, "%d", *(s16 *)data); | |
1023 | else | |
1024 | seq_printf(m, "%u", *(u16 *)data); | |
1025 | break; | |
1026 | case 8: | |
1027 | if (sign) | |
1028 | seq_printf(m, "%d", *(s8 *)data); | |
1029 | else | |
1030 | seq_printf(m, "%u", *(u8 *)data); | |
1031 | break; | |
1032 | default: | |
1033 | btf_int_bits_seq_show(btf, t, data, bits_offset, m); | |
1034 | } | |
1035 | } | |
1036 | ||
69b693f0 MKL |
1037 | static const struct btf_kind_operations int_ops = { |
1038 | .check_meta = btf_int_check_meta, | |
eb3f595d | 1039 | .resolve = btf_df_resolve, |
179cde8c | 1040 | .check_member = btf_int_check_member, |
69b693f0 | 1041 | .log_details = btf_int_log, |
b00b8dae | 1042 | .seq_show = btf_int_seq_show, |
69b693f0 MKL |
1043 | }; |
1044 | ||
179cde8c MKL |
1045 | static int btf_modifier_check_member(struct btf_verifier_env *env, |
1046 | const struct btf_type *struct_type, | |
1047 | const struct btf_member *member, | |
1048 | const struct btf_type *member_type) | |
1049 | { | |
1050 | const struct btf_type *resolved_type; | |
1051 | u32 resolved_type_id = member->type; | |
1052 | struct btf_member resolved_member; | |
1053 | struct btf *btf = env->btf; | |
1054 | ||
1055 | resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL); | |
1056 | if (!resolved_type) { | |
1057 | btf_verifier_log_member(env, struct_type, member, | |
1058 | "Invalid member"); | |
1059 | return -EINVAL; | |
1060 | } | |
1061 | ||
1062 | resolved_member = *member; | |
1063 | resolved_member.type = resolved_type_id; | |
1064 | ||
1065 | return btf_type_ops(resolved_type)->check_member(env, struct_type, | |
1066 | &resolved_member, | |
1067 | resolved_type); | |
1068 | } | |
1069 | ||
1070 | static int btf_ptr_check_member(struct btf_verifier_env *env, | |
1071 | const struct btf_type *struct_type, | |
1072 | const struct btf_member *member, | |
1073 | const struct btf_type *member_type) | |
1074 | { | |
1075 | u32 struct_size, struct_bits_off, bytes_offset; | |
1076 | ||
1077 | struct_size = struct_type->size; | |
1078 | struct_bits_off = member->offset; | |
1079 | bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); | |
1080 | ||
1081 | if (BITS_PER_BYTE_MASKED(struct_bits_off)) { | |
1082 | btf_verifier_log_member(env, struct_type, member, | |
1083 | "Member is not byte aligned"); | |
1084 | return -EINVAL; | |
1085 | } | |
1086 | ||
1087 | if (struct_size - bytes_offset < sizeof(void *)) { | |
1088 | btf_verifier_log_member(env, struct_type, member, | |
1089 | "Member exceeds struct_size"); | |
1090 | return -EINVAL; | |
1091 | } | |
1092 | ||
1093 | return 0; | |
1094 | } | |
1095 | ||
69b693f0 MKL |
1096 | static int btf_ref_type_check_meta(struct btf_verifier_env *env, |
1097 | const struct btf_type *t, | |
1098 | u32 meta_left) | |
1099 | { | |
1100 | if (btf_type_vlen(t)) { | |
1101 | btf_verifier_log_type(env, t, "vlen != 0"); | |
1102 | return -EINVAL; | |
1103 | } | |
1104 | ||
1105 | if (BTF_TYPE_PARENT(t->type)) { | |
1106 | btf_verifier_log_type(env, t, "Invalid type_id"); | |
1107 | return -EINVAL; | |
1108 | } | |
1109 | ||
1110 | btf_verifier_log_type(env, t, NULL); | |
1111 | ||
1112 | return 0; | |
1113 | } | |
1114 | ||
eb3f595d MKL |
1115 | static int btf_modifier_resolve(struct btf_verifier_env *env, |
1116 | const struct resolve_vertex *v) | |
1117 | { | |
1118 | const struct btf_type *t = v->t; | |
1119 | const struct btf_type *next_type; | |
1120 | u32 next_type_id = t->type; | |
1121 | struct btf *btf = env->btf; | |
1122 | u32 next_type_size = 0; | |
1123 | ||
1124 | next_type = btf_type_by_id(btf, next_type_id); | |
1125 | if (!next_type) { | |
1126 | btf_verifier_log_type(env, v->t, "Invalid type_id"); | |
1127 | return -EINVAL; | |
1128 | } | |
1129 | ||
1130 | /* "typedef void new_void", "const void"...etc */ | |
1131 | if (btf_type_is_void(next_type)) | |
1132 | goto resolved; | |
1133 | ||
1134 | if (!env_type_is_resolve_sink(env, next_type) && | |
1135 | !env_type_is_resolved(env, next_type_id)) | |
1136 | return env_stack_push(env, next_type, next_type_id); | |
1137 | ||
1138 | /* Figure out the resolved next_type_id with size. | |
1139 | * They will be stored in the current modifier's | |
1140 | * resolved_ids and resolved_sizes such that it can | |
1141 | * save us a few type-following when we use it later (e.g. in | |
1142 | * pretty print). | |
1143 | */ | |
1144 | if (!btf_type_id_size(btf, &next_type_id, &next_type_size) && | |
1145 | !btf_type_is_void(btf_type_id_resolve(btf, &next_type_id))) { | |
1146 | btf_verifier_log_type(env, v->t, "Invalid type_id"); | |
1147 | return -EINVAL; | |
1148 | } | |
1149 | ||
1150 | resolved: | |
1151 | env_stack_pop_resolved(env, next_type_id, next_type_size); | |
1152 | ||
1153 | return 0; | |
1154 | } | |
1155 | ||
1156 | static int btf_ptr_resolve(struct btf_verifier_env *env, | |
1157 | const struct resolve_vertex *v) | |
1158 | { | |
1159 | const struct btf_type *next_type; | |
1160 | const struct btf_type *t = v->t; | |
1161 | u32 next_type_id = t->type; | |
1162 | struct btf *btf = env->btf; | |
1163 | u32 next_type_size = 0; | |
1164 | ||
1165 | next_type = btf_type_by_id(btf, next_type_id); | |
1166 | if (!next_type) { | |
1167 | btf_verifier_log_type(env, v->t, "Invalid type_id"); | |
1168 | return -EINVAL; | |
1169 | } | |
1170 | ||
1171 | /* "void *" */ | |
1172 | if (btf_type_is_void(next_type)) | |
1173 | goto resolved; | |
1174 | ||
1175 | if (!env_type_is_resolve_sink(env, next_type) && | |
1176 | !env_type_is_resolved(env, next_type_id)) | |
1177 | return env_stack_push(env, next_type, next_type_id); | |
1178 | ||
1179 | /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY, | |
1180 | * the modifier may have stopped resolving when it was resolved | |
1181 | * to a ptr (last-resolved-ptr). | |
1182 | * | |
1183 | * We now need to continue from the last-resolved-ptr to | |
1184 | * ensure the last-resolved-ptr will not referring back to | |
1185 | * the currenct ptr (t). | |
1186 | */ | |
1187 | if (btf_type_is_modifier(next_type)) { | |
1188 | const struct btf_type *resolved_type; | |
1189 | u32 resolved_type_id; | |
1190 | ||
1191 | resolved_type_id = next_type_id; | |
1192 | resolved_type = btf_type_id_resolve(btf, &resolved_type_id); | |
1193 | ||
1194 | if (btf_type_is_ptr(resolved_type) && | |
1195 | !env_type_is_resolve_sink(env, resolved_type) && | |
1196 | !env_type_is_resolved(env, resolved_type_id)) | |
1197 | return env_stack_push(env, resolved_type, | |
1198 | resolved_type_id); | |
1199 | } | |
1200 | ||
1201 | if (!btf_type_id_size(btf, &next_type_id, &next_type_size) && | |
1202 | !btf_type_is_void(btf_type_id_resolve(btf, &next_type_id))) { | |
1203 | btf_verifier_log_type(env, v->t, "Invalid type_id"); | |
1204 | return -EINVAL; | |
1205 | } | |
1206 | ||
1207 | resolved: | |
1208 | env_stack_pop_resolved(env, next_type_id, 0); | |
1209 | ||
1210 | return 0; | |
1211 | } | |
1212 | ||
b00b8dae MKL |
1213 | static void btf_modifier_seq_show(const struct btf *btf, |
1214 | const struct btf_type *t, | |
1215 | u32 type_id, void *data, | |
1216 | u8 bits_offset, struct seq_file *m) | |
1217 | { | |
1218 | t = btf_type_id_resolve(btf, &type_id); | |
1219 | ||
1220 | btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m); | |
1221 | } | |
1222 | ||
1223 | static void btf_ptr_seq_show(const struct btf *btf, const struct btf_type *t, | |
1224 | u32 type_id, void *data, u8 bits_offset, | |
1225 | struct seq_file *m) | |
1226 | { | |
1227 | /* It is a hashed value */ | |
1228 | seq_printf(m, "%p", *(void **)data); | |
1229 | } | |
1230 | ||
69b693f0 MKL |
1231 | static void btf_ref_type_log(struct btf_verifier_env *env, |
1232 | const struct btf_type *t) | |
1233 | { | |
1234 | btf_verifier_log(env, "type_id=%u", t->type); | |
1235 | } | |
1236 | ||
1237 | static struct btf_kind_operations modifier_ops = { | |
1238 | .check_meta = btf_ref_type_check_meta, | |
eb3f595d | 1239 | .resolve = btf_modifier_resolve, |
179cde8c | 1240 | .check_member = btf_modifier_check_member, |
69b693f0 | 1241 | .log_details = btf_ref_type_log, |
b00b8dae | 1242 | .seq_show = btf_modifier_seq_show, |
69b693f0 MKL |
1243 | }; |
1244 | ||
1245 | static struct btf_kind_operations ptr_ops = { | |
1246 | .check_meta = btf_ref_type_check_meta, | |
eb3f595d | 1247 | .resolve = btf_ptr_resolve, |
179cde8c | 1248 | .check_member = btf_ptr_check_member, |
69b693f0 | 1249 | .log_details = btf_ref_type_log, |
b00b8dae | 1250 | .seq_show = btf_ptr_seq_show, |
69b693f0 MKL |
1251 | }; |
1252 | ||
1253 | static struct btf_kind_operations fwd_ops = { | |
1254 | .check_meta = btf_ref_type_check_meta, | |
eb3f595d | 1255 | .resolve = btf_df_resolve, |
179cde8c | 1256 | .check_member = btf_df_check_member, |
69b693f0 | 1257 | .log_details = btf_ref_type_log, |
b00b8dae | 1258 | .seq_show = btf_df_seq_show, |
69b693f0 MKL |
1259 | }; |
1260 | ||
179cde8c MKL |
1261 | static int btf_array_check_member(struct btf_verifier_env *env, |
1262 | const struct btf_type *struct_type, | |
1263 | const struct btf_member *member, | |
1264 | const struct btf_type *member_type) | |
1265 | { | |
1266 | u32 struct_bits_off = member->offset; | |
1267 | u32 struct_size, bytes_offset; | |
1268 | u32 array_type_id, array_size; | |
1269 | struct btf *btf = env->btf; | |
1270 | ||
1271 | if (BITS_PER_BYTE_MASKED(struct_bits_off)) { | |
1272 | btf_verifier_log_member(env, struct_type, member, | |
1273 | "Member is not byte aligned"); | |
1274 | return -EINVAL; | |
1275 | } | |
1276 | ||
1277 | array_type_id = member->type; | |
1278 | btf_type_id_size(btf, &array_type_id, &array_size); | |
1279 | struct_size = struct_type->size; | |
1280 | bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); | |
1281 | if (struct_size - bytes_offset < array_size) { | |
1282 | btf_verifier_log_member(env, struct_type, member, | |
1283 | "Member exceeds struct_size"); | |
1284 | return -EINVAL; | |
1285 | } | |
1286 | ||
1287 | return 0; | |
1288 | } | |
1289 | ||
69b693f0 MKL |
1290 | static s32 btf_array_check_meta(struct btf_verifier_env *env, |
1291 | const struct btf_type *t, | |
1292 | u32 meta_left) | |
1293 | { | |
1294 | const struct btf_array *array = btf_type_array(t); | |
1295 | u32 meta_needed = sizeof(*array); | |
1296 | ||
1297 | if (meta_left < meta_needed) { | |
1298 | btf_verifier_log_basic(env, t, | |
1299 | "meta_left:%u meta_needed:%u", | |
1300 | meta_left, meta_needed); | |
1301 | return -EINVAL; | |
1302 | } | |
1303 | ||
1304 | if (btf_type_vlen(t)) { | |
1305 | btf_verifier_log_type(env, t, "vlen != 0"); | |
1306 | return -EINVAL; | |
1307 | } | |
1308 | ||
1309 | /* We are a little forgiving on array->index_type since | |
1310 | * the kernel is not using it. | |
1311 | */ | |
1312 | /* Array elem cannot be in type void, | |
1313 | * so !array->type is not allowed. | |
1314 | */ | |
1315 | if (!array->type || BTF_TYPE_PARENT(array->type)) { | |
1316 | btf_verifier_log_type(env, t, "Invalid type_id"); | |
1317 | return -EINVAL; | |
1318 | } | |
1319 | ||
1320 | btf_verifier_log_type(env, t, NULL); | |
1321 | ||
1322 | return meta_needed; | |
1323 | } | |
1324 | ||
eb3f595d MKL |
1325 | static int btf_array_resolve(struct btf_verifier_env *env, |
1326 | const struct resolve_vertex *v) | |
1327 | { | |
1328 | const struct btf_array *array = btf_type_array(v->t); | |
1329 | const struct btf_type *elem_type; | |
1330 | u32 elem_type_id = array->type; | |
1331 | struct btf *btf = env->btf; | |
1332 | u32 elem_size; | |
1333 | ||
1334 | elem_type = btf_type_by_id(btf, elem_type_id); | |
1335 | if (btf_type_is_void_or_null(elem_type)) { | |
1336 | btf_verifier_log_type(env, v->t, | |
1337 | "Invalid elem"); | |
1338 | return -EINVAL; | |
1339 | } | |
1340 | ||
1341 | if (!env_type_is_resolve_sink(env, elem_type) && | |
1342 | !env_type_is_resolved(env, elem_type_id)) | |
1343 | return env_stack_push(env, elem_type, elem_type_id); | |
1344 | ||
1345 | elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); | |
1346 | if (!elem_type) { | |
1347 | btf_verifier_log_type(env, v->t, "Invalid elem"); | |
1348 | return -EINVAL; | |
1349 | } | |
1350 | ||
1351 | if (btf_type_is_int(elem_type)) { | |
1352 | int int_type_data = btf_type_int(elem_type); | |
1353 | u16 nr_bits = BTF_INT_BITS(int_type_data); | |
1354 | u16 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits); | |
1355 | ||
1356 | /* Put more restriction on array of int. The int cannot | |
1357 | * be a bit field and it must be either u8/u16/u32/u64. | |
1358 | */ | |
1359 | if (BITS_PER_BYTE_MASKED(nr_bits) || | |
1360 | BTF_INT_OFFSET(int_type_data) || | |
1361 | (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) && | |
1362 | nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64))) { | |
1363 | btf_verifier_log_type(env, v->t, | |
1364 | "Invalid array of int"); | |
1365 | return -EINVAL; | |
1366 | } | |
1367 | } | |
1368 | ||
1369 | if (array->nelems && elem_size > U32_MAX / array->nelems) { | |
1370 | btf_verifier_log_type(env, v->t, | |
1371 | "Array size overflows U32_MAX"); | |
1372 | return -EINVAL; | |
1373 | } | |
1374 | ||
1375 | env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems); | |
1376 | ||
1377 | return 0; | |
1378 | } | |
1379 | ||
69b693f0 MKL |
1380 | static void btf_array_log(struct btf_verifier_env *env, |
1381 | const struct btf_type *t) | |
1382 | { | |
1383 | const struct btf_array *array = btf_type_array(t); | |
1384 | ||
1385 | btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u", | |
1386 | array->type, array->index_type, array->nelems); | |
1387 | } | |
1388 | ||
b00b8dae MKL |
1389 | static void btf_array_seq_show(const struct btf *btf, const struct btf_type *t, |
1390 | u32 type_id, void *data, u8 bits_offset, | |
1391 | struct seq_file *m) | |
1392 | { | |
1393 | const struct btf_array *array = btf_type_array(t); | |
1394 | const struct btf_kind_operations *elem_ops; | |
1395 | const struct btf_type *elem_type; | |
1396 | u32 i, elem_size, elem_type_id; | |
1397 | ||
1398 | elem_type_id = array->type; | |
1399 | elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); | |
1400 | elem_ops = btf_type_ops(elem_type); | |
1401 | seq_puts(m, "["); | |
1402 | for (i = 0; i < array->nelems; i++) { | |
1403 | if (i) | |
1404 | seq_puts(m, ","); | |
1405 | ||
1406 | elem_ops->seq_show(btf, elem_type, elem_type_id, data, | |
1407 | bits_offset, m); | |
1408 | data += elem_size; | |
1409 | } | |
1410 | seq_puts(m, "]"); | |
1411 | } | |
1412 | ||
69b693f0 MKL |
1413 | static struct btf_kind_operations array_ops = { |
1414 | .check_meta = btf_array_check_meta, | |
eb3f595d | 1415 | .resolve = btf_array_resolve, |
179cde8c | 1416 | .check_member = btf_array_check_member, |
69b693f0 | 1417 | .log_details = btf_array_log, |
b00b8dae | 1418 | .seq_show = btf_array_seq_show, |
69b693f0 MKL |
1419 | }; |
1420 | ||
179cde8c MKL |
1421 | static int btf_struct_check_member(struct btf_verifier_env *env, |
1422 | const struct btf_type *struct_type, | |
1423 | const struct btf_member *member, | |
1424 | const struct btf_type *member_type) | |
1425 | { | |
1426 | u32 struct_bits_off = member->offset; | |
1427 | u32 struct_size, bytes_offset; | |
1428 | ||
1429 | if (BITS_PER_BYTE_MASKED(struct_bits_off)) { | |
1430 | btf_verifier_log_member(env, struct_type, member, | |
1431 | "Member is not byte aligned"); | |
1432 | return -EINVAL; | |
1433 | } | |
1434 | ||
1435 | struct_size = struct_type->size; | |
1436 | bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); | |
1437 | if (struct_size - bytes_offset < member_type->size) { | |
1438 | btf_verifier_log_member(env, struct_type, member, | |
1439 | "Member exceeds struct_size"); | |
1440 | return -EINVAL; | |
1441 | } | |
1442 | ||
1443 | return 0; | |
1444 | } | |
1445 | ||
69b693f0 MKL |
1446 | static s32 btf_struct_check_meta(struct btf_verifier_env *env, |
1447 | const struct btf_type *t, | |
1448 | u32 meta_left) | |
1449 | { | |
1450 | bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION; | |
1451 | const struct btf_member *member; | |
1452 | struct btf *btf = env->btf; | |
1453 | u32 struct_size = t->size; | |
1454 | u32 meta_needed; | |
1455 | u16 i; | |
1456 | ||
1457 | meta_needed = btf_type_vlen(t) * sizeof(*member); | |
1458 | if (meta_left < meta_needed) { | |
1459 | btf_verifier_log_basic(env, t, | |
1460 | "meta_left:%u meta_needed:%u", | |
1461 | meta_left, meta_needed); | |
1462 | return -EINVAL; | |
1463 | } | |
1464 | ||
1465 | btf_verifier_log_type(env, t, NULL); | |
1466 | ||
1467 | for_each_member(i, t, member) { | |
fbcf93eb | 1468 | if (!btf_name_offset_valid(btf, member->name_off)) { |
69b693f0 MKL |
1469 | btf_verifier_log_member(env, t, member, |
1470 | "Invalid member name_offset:%u", | |
fbcf93eb | 1471 | member->name_off); |
69b693f0 MKL |
1472 | return -EINVAL; |
1473 | } | |
1474 | ||
1475 | /* A member cannot be in type void */ | |
1476 | if (!member->type || BTF_TYPE_PARENT(member->type)) { | |
1477 | btf_verifier_log_member(env, t, member, | |
1478 | "Invalid type_id"); | |
1479 | return -EINVAL; | |
1480 | } | |
1481 | ||
1482 | if (is_union && member->offset) { | |
1483 | btf_verifier_log_member(env, t, member, | |
1484 | "Invalid member bits_offset"); | |
1485 | return -EINVAL; | |
1486 | } | |
1487 | ||
1488 | if (BITS_ROUNDUP_BYTES(member->offset) > struct_size) { | |
1489 | btf_verifier_log_member(env, t, member, | |
1490 | "Memmber bits_offset exceeds its struct size"); | |
1491 | return -EINVAL; | |
1492 | } | |
1493 | ||
1494 | btf_verifier_log_member(env, t, member, NULL); | |
1495 | } | |
1496 | ||
1497 | return meta_needed; | |
1498 | } | |
1499 | ||
eb3f595d MKL |
1500 | static int btf_struct_resolve(struct btf_verifier_env *env, |
1501 | const struct resolve_vertex *v) | |
1502 | { | |
1503 | const struct btf_member *member; | |
179cde8c | 1504 | int err; |
eb3f595d MKL |
1505 | u16 i; |
1506 | ||
1507 | /* Before continue resolving the next_member, | |
1508 | * ensure the last member is indeed resolved to a | |
1509 | * type with size info. | |
1510 | */ | |
1511 | if (v->next_member) { | |
179cde8c | 1512 | const struct btf_type *last_member_type; |
eb3f595d MKL |
1513 | const struct btf_member *last_member; |
1514 | u16 last_member_type_id; | |
1515 | ||
1516 | last_member = btf_type_member(v->t) + v->next_member - 1; | |
1517 | last_member_type_id = last_member->type; | |
1518 | if (WARN_ON_ONCE(!env_type_is_resolved(env, | |
1519 | last_member_type_id))) | |
1520 | return -EINVAL; | |
179cde8c MKL |
1521 | |
1522 | last_member_type = btf_type_by_id(env->btf, | |
1523 | last_member_type_id); | |
1524 | err = btf_type_ops(last_member_type)->check_member(env, v->t, | |
1525 | last_member, | |
1526 | last_member_type); | |
1527 | if (err) | |
1528 | return err; | |
eb3f595d MKL |
1529 | } |
1530 | ||
1531 | for_each_member_from(i, v->next_member, v->t, member) { | |
1532 | u32 member_type_id = member->type; | |
1533 | const struct btf_type *member_type = btf_type_by_id(env->btf, | |
1534 | member_type_id); | |
1535 | ||
1536 | if (btf_type_is_void_or_null(member_type)) { | |
1537 | btf_verifier_log_member(env, v->t, member, | |
1538 | "Invalid member"); | |
1539 | return -EINVAL; | |
1540 | } | |
1541 | ||
1542 | if (!env_type_is_resolve_sink(env, member_type) && | |
1543 | !env_type_is_resolved(env, member_type_id)) { | |
1544 | env_stack_set_next_member(env, i + 1); | |
1545 | return env_stack_push(env, member_type, member_type_id); | |
1546 | } | |
179cde8c MKL |
1547 | |
1548 | err = btf_type_ops(member_type)->check_member(env, v->t, | |
1549 | member, | |
1550 | member_type); | |
1551 | if (err) | |
1552 | return err; | |
eb3f595d MKL |
1553 | } |
1554 | ||
1555 | env_stack_pop_resolved(env, 0, 0); | |
1556 | ||
1557 | return 0; | |
1558 | } | |
1559 | ||
69b693f0 MKL |
1560 | static void btf_struct_log(struct btf_verifier_env *env, |
1561 | const struct btf_type *t) | |
1562 | { | |
1563 | btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); | |
1564 | } | |
1565 | ||
b00b8dae MKL |
1566 | static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t, |
1567 | u32 type_id, void *data, u8 bits_offset, | |
1568 | struct seq_file *m) | |
1569 | { | |
1570 | const char *seq = BTF_INFO_KIND(t->info) == BTF_KIND_UNION ? "|" : ","; | |
1571 | const struct btf_member *member; | |
1572 | u32 i; | |
1573 | ||
1574 | seq_puts(m, "{"); | |
1575 | for_each_member(i, t, member) { | |
1576 | const struct btf_type *member_type = btf_type_by_id(btf, | |
1577 | member->type); | |
1578 | u32 member_offset = member->offset; | |
1579 | u32 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset); | |
1580 | u8 bits8_offset = BITS_PER_BYTE_MASKED(member_offset); | |
1581 | const struct btf_kind_operations *ops; | |
1582 | ||
1583 | if (i) | |
1584 | seq_puts(m, seq); | |
1585 | ||
1586 | ops = btf_type_ops(member_type); | |
1587 | ops->seq_show(btf, member_type, member->type, | |
1588 | data + bytes_offset, bits8_offset, m); | |
1589 | } | |
1590 | seq_puts(m, "}"); | |
1591 | } | |
1592 | ||
69b693f0 MKL |
1593 | static struct btf_kind_operations struct_ops = { |
1594 | .check_meta = btf_struct_check_meta, | |
eb3f595d | 1595 | .resolve = btf_struct_resolve, |
179cde8c | 1596 | .check_member = btf_struct_check_member, |
69b693f0 | 1597 | .log_details = btf_struct_log, |
b00b8dae | 1598 | .seq_show = btf_struct_seq_show, |
69b693f0 MKL |
1599 | }; |
1600 | ||
179cde8c MKL |
1601 | static int btf_enum_check_member(struct btf_verifier_env *env, |
1602 | const struct btf_type *struct_type, | |
1603 | const struct btf_member *member, | |
1604 | const struct btf_type *member_type) | |
1605 | { | |
1606 | u32 struct_bits_off = member->offset; | |
1607 | u32 struct_size, bytes_offset; | |
1608 | ||
1609 | if (BITS_PER_BYTE_MASKED(struct_bits_off)) { | |
1610 | btf_verifier_log_member(env, struct_type, member, | |
1611 | "Member is not byte aligned"); | |
1612 | return -EINVAL; | |
1613 | } | |
1614 | ||
1615 | struct_size = struct_type->size; | |
1616 | bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); | |
1617 | if (struct_size - bytes_offset < sizeof(int)) { | |
1618 | btf_verifier_log_member(env, struct_type, member, | |
1619 | "Member exceeds struct_size"); | |
1620 | return -EINVAL; | |
1621 | } | |
1622 | ||
1623 | return 0; | |
1624 | } | |
1625 | ||
69b693f0 MKL |
1626 | static s32 btf_enum_check_meta(struct btf_verifier_env *env, |
1627 | const struct btf_type *t, | |
1628 | u32 meta_left) | |
1629 | { | |
1630 | const struct btf_enum *enums = btf_type_enum(t); | |
1631 | struct btf *btf = env->btf; | |
1632 | u16 i, nr_enums; | |
1633 | u32 meta_needed; | |
1634 | ||
1635 | nr_enums = btf_type_vlen(t); | |
1636 | meta_needed = nr_enums * sizeof(*enums); | |
1637 | ||
1638 | if (meta_left < meta_needed) { | |
1639 | btf_verifier_log_basic(env, t, | |
1640 | "meta_left:%u meta_needed:%u", | |
1641 | meta_left, meta_needed); | |
1642 | return -EINVAL; | |
1643 | } | |
1644 | ||
1645 | if (t->size != sizeof(int)) { | |
1646 | btf_verifier_log_type(env, t, "Expected size:%zu", | |
1647 | sizeof(int)); | |
1648 | return -EINVAL; | |
1649 | } | |
1650 | ||
1651 | btf_verifier_log_type(env, t, NULL); | |
1652 | ||
1653 | for (i = 0; i < nr_enums; i++) { | |
fbcf93eb | 1654 | if (!btf_name_offset_valid(btf, enums[i].name_off)) { |
69b693f0 | 1655 | btf_verifier_log(env, "\tInvalid name_offset:%u", |
fbcf93eb | 1656 | enums[i].name_off); |
69b693f0 MKL |
1657 | return -EINVAL; |
1658 | } | |
1659 | ||
1660 | btf_verifier_log(env, "\t%s val=%d\n", | |
fbcf93eb | 1661 | btf_name_by_offset(btf, enums[i].name_off), |
69b693f0 MKL |
1662 | enums[i].val); |
1663 | } | |
1664 | ||
1665 | return meta_needed; | |
1666 | } | |
1667 | ||
1668 | static void btf_enum_log(struct btf_verifier_env *env, | |
1669 | const struct btf_type *t) | |
1670 | { | |
1671 | btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); | |
1672 | } | |
1673 | ||
b00b8dae MKL |
1674 | static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t, |
1675 | u32 type_id, void *data, u8 bits_offset, | |
1676 | struct seq_file *m) | |
1677 | { | |
1678 | const struct btf_enum *enums = btf_type_enum(t); | |
1679 | u32 i, nr_enums = btf_type_vlen(t); | |
1680 | int v = *(int *)data; | |
1681 | ||
1682 | for (i = 0; i < nr_enums; i++) { | |
1683 | if (v == enums[i].val) { | |
1684 | seq_printf(m, "%s", | |
fbcf93eb | 1685 | btf_name_by_offset(btf, enums[i].name_off)); |
b00b8dae MKL |
1686 | return; |
1687 | } | |
1688 | } | |
1689 | ||
1690 | seq_printf(m, "%d", v); | |
1691 | } | |
1692 | ||
69b693f0 MKL |
1693 | static struct btf_kind_operations enum_ops = { |
1694 | .check_meta = btf_enum_check_meta, | |
eb3f595d | 1695 | .resolve = btf_df_resolve, |
179cde8c | 1696 | .check_member = btf_enum_check_member, |
69b693f0 | 1697 | .log_details = btf_enum_log, |
b00b8dae | 1698 | .seq_show = btf_enum_seq_show, |
69b693f0 MKL |
1699 | }; |
1700 | ||
1701 | static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = { | |
1702 | [BTF_KIND_INT] = &int_ops, | |
1703 | [BTF_KIND_PTR] = &ptr_ops, | |
1704 | [BTF_KIND_ARRAY] = &array_ops, | |
1705 | [BTF_KIND_STRUCT] = &struct_ops, | |
1706 | [BTF_KIND_UNION] = &struct_ops, | |
1707 | [BTF_KIND_ENUM] = &enum_ops, | |
1708 | [BTF_KIND_FWD] = &fwd_ops, | |
1709 | [BTF_KIND_TYPEDEF] = &modifier_ops, | |
1710 | [BTF_KIND_VOLATILE] = &modifier_ops, | |
1711 | [BTF_KIND_CONST] = &modifier_ops, | |
1712 | [BTF_KIND_RESTRICT] = &modifier_ops, | |
1713 | }; | |
1714 | ||
1715 | static s32 btf_check_meta(struct btf_verifier_env *env, | |
1716 | const struct btf_type *t, | |
1717 | u32 meta_left) | |
1718 | { | |
1719 | u32 saved_meta_left = meta_left; | |
1720 | s32 var_meta_size; | |
1721 | ||
1722 | if (meta_left < sizeof(*t)) { | |
1723 | btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu", | |
1724 | env->log_type_id, meta_left, sizeof(*t)); | |
1725 | return -EINVAL; | |
1726 | } | |
1727 | meta_left -= sizeof(*t); | |
1728 | ||
1729 | if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX || | |
1730 | BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) { | |
1731 | btf_verifier_log(env, "[%u] Invalid kind:%u", | |
1732 | env->log_type_id, BTF_INFO_KIND(t->info)); | |
1733 | return -EINVAL; | |
1734 | } | |
1735 | ||
fbcf93eb | 1736 | if (!btf_name_offset_valid(env->btf, t->name_off)) { |
69b693f0 | 1737 | btf_verifier_log(env, "[%u] Invalid name_offset:%u", |
fbcf93eb | 1738 | env->log_type_id, t->name_off); |
69b693f0 MKL |
1739 | return -EINVAL; |
1740 | } | |
1741 | ||
1742 | var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left); | |
1743 | if (var_meta_size < 0) | |
1744 | return var_meta_size; | |
1745 | ||
1746 | meta_left -= var_meta_size; | |
1747 | ||
1748 | return saved_meta_left - meta_left; | |
1749 | } | |
1750 | ||
1751 | static int btf_check_all_metas(struct btf_verifier_env *env) | |
1752 | { | |
1753 | struct btf *btf = env->btf; | |
1754 | struct btf_header *hdr; | |
1755 | void *cur, *end; | |
1756 | ||
1757 | hdr = btf->hdr; | |
1758 | cur = btf->nohdr_data + hdr->type_off; | |
1759 | end = btf->nohdr_data + hdr->str_off; | |
1760 | ||
1761 | env->log_type_id = 1; | |
1762 | while (cur < end) { | |
1763 | struct btf_type *t = cur; | |
1764 | s32 meta_size; | |
1765 | ||
1766 | meta_size = btf_check_meta(env, t, end - cur); | |
1767 | if (meta_size < 0) | |
1768 | return meta_size; | |
1769 | ||
1770 | btf_add_type(env, t); | |
1771 | cur += meta_size; | |
1772 | env->log_type_id++; | |
1773 | } | |
1774 | ||
1775 | return 0; | |
1776 | } | |
1777 | ||
eb3f595d MKL |
1778 | static int btf_resolve(struct btf_verifier_env *env, |
1779 | const struct btf_type *t, u32 type_id) | |
1780 | { | |
1781 | const struct resolve_vertex *v; | |
1782 | int err = 0; | |
1783 | ||
1784 | env->resolve_mode = RESOLVE_TBD; | |
1785 | env_stack_push(env, t, type_id); | |
1786 | while (!err && (v = env_stack_peak(env))) { | |
1787 | env->log_type_id = v->type_id; | |
1788 | err = btf_type_ops(v->t)->resolve(env, v); | |
1789 | } | |
1790 | ||
1791 | env->log_type_id = type_id; | |
1792 | if (err == -E2BIG) | |
1793 | btf_verifier_log_type(env, t, | |
1794 | "Exceeded max resolving depth:%u", | |
1795 | MAX_RESOLVE_DEPTH); | |
1796 | else if (err == -EEXIST) | |
1797 | btf_verifier_log_type(env, t, "Loop detected"); | |
1798 | ||
1799 | return err; | |
1800 | } | |
1801 | ||
1802 | static bool btf_resolve_valid(struct btf_verifier_env *env, | |
1803 | const struct btf_type *t, | |
1804 | u32 type_id) | |
1805 | { | |
1806 | struct btf *btf = env->btf; | |
1807 | ||
1808 | if (!env_type_is_resolved(env, type_id)) | |
1809 | return false; | |
1810 | ||
1811 | if (btf_type_is_struct(t)) | |
1812 | return !btf->resolved_ids[type_id] && | |
1813 | !btf->resolved_sizes[type_id]; | |
1814 | ||
1815 | if (btf_type_is_modifier(t) || btf_type_is_ptr(t)) { | |
1816 | t = btf_type_id_resolve(btf, &type_id); | |
1817 | return t && !btf_type_is_modifier(t); | |
1818 | } | |
1819 | ||
1820 | if (btf_type_is_array(t)) { | |
1821 | const struct btf_array *array = btf_type_array(t); | |
1822 | const struct btf_type *elem_type; | |
1823 | u32 elem_type_id = array->type; | |
1824 | u32 elem_size; | |
1825 | ||
1826 | elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); | |
1827 | return elem_type && !btf_type_is_modifier(elem_type) && | |
1828 | (array->nelems * elem_size == | |
1829 | btf->resolved_sizes[type_id]); | |
1830 | } | |
1831 | ||
1832 | return false; | |
1833 | } | |
1834 | ||
1835 | static int btf_check_all_types(struct btf_verifier_env *env) | |
1836 | { | |
1837 | struct btf *btf = env->btf; | |
1838 | u32 type_id; | |
1839 | int err; | |
1840 | ||
1841 | err = env_resolve_init(env); | |
1842 | if (err) | |
1843 | return err; | |
1844 | ||
1845 | env->phase++; | |
1846 | for (type_id = 1; type_id <= btf->nr_types; type_id++) { | |
1847 | const struct btf_type *t = btf_type_by_id(btf, type_id); | |
1848 | ||
1849 | env->log_type_id = type_id; | |
1850 | if (btf_type_needs_resolve(t) && | |
1851 | !env_type_is_resolved(env, type_id)) { | |
1852 | err = btf_resolve(env, t, type_id); | |
1853 | if (err) | |
1854 | return err; | |
1855 | } | |
1856 | ||
1857 | if (btf_type_needs_resolve(t) && | |
1858 | !btf_resolve_valid(env, t, type_id)) { | |
1859 | btf_verifier_log_type(env, t, "Invalid resolve state"); | |
1860 | return -EINVAL; | |
1861 | } | |
1862 | } | |
1863 | ||
1864 | return 0; | |
1865 | } | |
1866 | ||
69b693f0 MKL |
1867 | static int btf_parse_type_sec(struct btf_verifier_env *env) |
1868 | { | |
eb3f595d MKL |
1869 | int err; |
1870 | ||
1871 | err = btf_check_all_metas(env); | |
1872 | if (err) | |
1873 | return err; | |
1874 | ||
1875 | return btf_check_all_types(env); | |
69b693f0 MKL |
1876 | } |
1877 | ||
1878 | static int btf_parse_str_sec(struct btf_verifier_env *env) | |
1879 | { | |
1880 | const struct btf_header *hdr; | |
1881 | struct btf *btf = env->btf; | |
1882 | const char *start, *end; | |
1883 | ||
1884 | hdr = btf->hdr; | |
1885 | start = btf->nohdr_data + hdr->str_off; | |
1886 | end = start + hdr->str_len; | |
1887 | ||
1888 | if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || | |
1889 | start[0] || end[-1]) { | |
1890 | btf_verifier_log(env, "Invalid string section"); | |
1891 | return -EINVAL; | |
1892 | } | |
1893 | ||
1894 | btf->strings = start; | |
1895 | ||
1896 | return 0; | |
1897 | } | |
1898 | ||
1899 | static int btf_parse_hdr(struct btf_verifier_env *env) | |
1900 | { | |
1901 | const struct btf_header *hdr; | |
1902 | struct btf *btf = env->btf; | |
1903 | u32 meta_left; | |
1904 | ||
1905 | if (btf->data_size < sizeof(*hdr)) { | |
1906 | btf_verifier_log(env, "btf_header not found"); | |
1907 | return -EINVAL; | |
1908 | } | |
1909 | ||
1910 | btf_verifier_log_hdr(env); | |
1911 | ||
1912 | hdr = btf->hdr; | |
1913 | if (hdr->magic != BTF_MAGIC) { | |
1914 | btf_verifier_log(env, "Invalid magic"); | |
1915 | return -EINVAL; | |
1916 | } | |
1917 | ||
1918 | if (hdr->version != BTF_VERSION) { | |
1919 | btf_verifier_log(env, "Unsupported version"); | |
1920 | return -ENOTSUPP; | |
1921 | } | |
1922 | ||
1923 | if (hdr->flags) { | |
1924 | btf_verifier_log(env, "Unsupported flags"); | |
1925 | return -ENOTSUPP; | |
1926 | } | |
1927 | ||
1928 | meta_left = btf->data_size - sizeof(*hdr); | |
1929 | if (!meta_left) { | |
1930 | btf_verifier_log(env, "No data"); | |
1931 | return -EINVAL; | |
1932 | } | |
1933 | ||
1934 | if (meta_left < hdr->type_off || hdr->str_off <= hdr->type_off || | |
1935 | /* Type section must align to 4 bytes */ | |
1936 | hdr->type_off & (sizeof(u32) - 1)) { | |
1937 | btf_verifier_log(env, "Invalid type_off"); | |
1938 | return -EINVAL; | |
1939 | } | |
1940 | ||
1941 | if (meta_left < hdr->str_off || | |
1942 | meta_left - hdr->str_off < hdr->str_len) { | |
1943 | btf_verifier_log(env, "Invalid str_off or str_len"); | |
1944 | return -EINVAL; | |
1945 | } | |
1946 | ||
1947 | btf->nohdr_data = btf->hdr + 1; | |
1948 | ||
1949 | return 0; | |
1950 | } | |
1951 | ||
1952 | static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size, | |
1953 | u32 log_level, char __user *log_ubuf, u32 log_size) | |
1954 | { | |
1955 | struct btf_verifier_env *env = NULL; | |
1956 | struct bpf_verifier_log *log; | |
1957 | struct btf *btf = NULL; | |
1958 | u8 *data; | |
1959 | int err; | |
1960 | ||
1961 | if (btf_data_size > BTF_MAX_SIZE) | |
1962 | return ERR_PTR(-E2BIG); | |
1963 | ||
1964 | env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); | |
1965 | if (!env) | |
1966 | return ERR_PTR(-ENOMEM); | |
1967 | ||
1968 | log = &env->log; | |
1969 | if (log_level || log_ubuf || log_size) { | |
1970 | /* user requested verbose verifier output | |
1971 | * and supplied buffer to store the verification trace | |
1972 | */ | |
1973 | log->level = log_level; | |
1974 | log->ubuf = log_ubuf; | |
1975 | log->len_total = log_size; | |
1976 | ||
1977 | /* log attributes have to be sane */ | |
1978 | if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 || | |
1979 | !log->level || !log->ubuf) { | |
1980 | err = -EINVAL; | |
1981 | goto errout; | |
1982 | } | |
1983 | } | |
1984 | ||
1985 | btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); | |
1986 | if (!btf) { | |
1987 | err = -ENOMEM; | |
1988 | goto errout; | |
1989 | } | |
1990 | ||
1991 | data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN); | |
1992 | if (!data) { | |
1993 | err = -ENOMEM; | |
1994 | goto errout; | |
1995 | } | |
1996 | ||
1997 | btf->data = data; | |
1998 | btf->data_size = btf_data_size; | |
1999 | ||
2000 | if (copy_from_user(data, btf_data, btf_data_size)) { | |
2001 | err = -EFAULT; | |
2002 | goto errout; | |
2003 | } | |
2004 | ||
2005 | env->btf = btf; | |
2006 | ||
2007 | err = btf_parse_hdr(env); | |
2008 | if (err) | |
2009 | goto errout; | |
2010 | ||
2011 | err = btf_parse_str_sec(env); | |
2012 | if (err) | |
2013 | goto errout; | |
2014 | ||
2015 | err = btf_parse_type_sec(env); | |
2016 | if (err) | |
2017 | goto errout; | |
2018 | ||
2019 | if (!err && log->level && bpf_verifier_log_full(log)) { | |
2020 | err = -ENOSPC; | |
2021 | goto errout; | |
2022 | } | |
2023 | ||
2024 | if (!err) { | |
2025 | btf_verifier_env_free(env); | |
82e96972 | 2026 | refcount_set(&btf->refcnt, 1); |
69b693f0 MKL |
2027 | return btf; |
2028 | } | |
2029 | ||
2030 | errout: | |
2031 | btf_verifier_env_free(env); | |
2032 | if (btf) | |
2033 | btf_free(btf); | |
2034 | return ERR_PTR(err); | |
2035 | } | |
b00b8dae MKL |
2036 | |
2037 | void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj, | |
2038 | struct seq_file *m) | |
2039 | { | |
2040 | const struct btf_type *t = btf_type_by_id(btf, type_id); | |
2041 | ||
2042 | btf_type_ops(t)->seq_show(btf, t, type_id, obj, 0, m); | |
2043 | } | |
f56a653c MKL |
2044 | |
2045 | static int btf_release(struct inode *inode, struct file *filp) | |
2046 | { | |
2047 | btf_put(filp->private_data); | |
2048 | return 0; | |
2049 | } | |
2050 | ||
60197cfb | 2051 | const struct file_operations btf_fops = { |
f56a653c MKL |
2052 | .release = btf_release, |
2053 | }; | |
2054 | ||
78958fca MKL |
2055 | static int __btf_new_fd(struct btf *btf) |
2056 | { | |
2057 | return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC); | |
2058 | } | |
2059 | ||
f56a653c MKL |
2060 | int btf_new_fd(const union bpf_attr *attr) |
2061 | { | |
2062 | struct btf *btf; | |
78958fca | 2063 | int ret; |
f56a653c MKL |
2064 | |
2065 | btf = btf_parse(u64_to_user_ptr(attr->btf), | |
2066 | attr->btf_size, attr->btf_log_level, | |
2067 | u64_to_user_ptr(attr->btf_log_buf), | |
2068 | attr->btf_log_size); | |
2069 | if (IS_ERR(btf)) | |
2070 | return PTR_ERR(btf); | |
2071 | ||
78958fca MKL |
2072 | ret = btf_alloc_id(btf); |
2073 | if (ret) { | |
2074 | btf_free(btf); | |
2075 | return ret; | |
2076 | } | |
2077 | ||
2078 | /* | |
2079 | * The BTF ID is published to the userspace. | |
2080 | * All BTF free must go through call_rcu() from | |
2081 | * now on (i.e. free by calling btf_put()). | |
2082 | */ | |
2083 | ||
2084 | ret = __btf_new_fd(btf); | |
2085 | if (ret < 0) | |
f56a653c MKL |
2086 | btf_put(btf); |
2087 | ||
78958fca | 2088 | return ret; |
f56a653c MKL |
2089 | } |
2090 | ||
2091 | struct btf *btf_get_by_fd(int fd) | |
2092 | { | |
2093 | struct btf *btf; | |
2094 | struct fd f; | |
2095 | ||
2096 | f = fdget(fd); | |
2097 | ||
2098 | if (!f.file) | |
2099 | return ERR_PTR(-EBADF); | |
2100 | ||
2101 | if (f.file->f_op != &btf_fops) { | |
2102 | fdput(f); | |
2103 | return ERR_PTR(-EINVAL); | |
2104 | } | |
2105 | ||
2106 | btf = f.file->private_data; | |
78958fca | 2107 | refcount_inc(&btf->refcnt); |
f56a653c MKL |
2108 | fdput(f); |
2109 | ||
2110 | return btf; | |
2111 | } | |
60197cfb MKL |
2112 | |
2113 | int btf_get_info_by_fd(const struct btf *btf, | |
2114 | const union bpf_attr *attr, | |
2115 | union bpf_attr __user *uattr) | |
2116 | { | |
62dab84c MKL |
2117 | struct bpf_btf_info __user *uinfo; |
2118 | struct bpf_btf_info info = {}; | |
2119 | u32 info_copy, btf_copy; | |
2120 | void __user *ubtf; | |
2121 | u32 uinfo_len; | |
60197cfb | 2122 | |
62dab84c MKL |
2123 | uinfo = u64_to_user_ptr(attr->info.info); |
2124 | uinfo_len = attr->info.info_len; | |
2125 | ||
2126 | info_copy = min_t(u32, uinfo_len, sizeof(info)); | |
2127 | if (copy_from_user(&info, uinfo, info_copy)) | |
2128 | return -EFAULT; | |
2129 | ||
2130 | info.id = btf->id; | |
2131 | ubtf = u64_to_user_ptr(info.btf); | |
2132 | btf_copy = min_t(u32, btf->data_size, info.btf_size); | |
2133 | if (copy_to_user(ubtf, btf->data, btf_copy)) | |
2134 | return -EFAULT; | |
2135 | info.btf_size = btf->data_size; | |
2136 | ||
2137 | if (copy_to_user(uinfo, &info, info_copy) || | |
2138 | put_user(info_copy, &uattr->info.info_len)) | |
60197cfb MKL |
2139 | return -EFAULT; |
2140 | ||
2141 | return 0; | |
2142 | } | |
78958fca MKL |
2143 | |
2144 | int btf_get_fd_by_id(u32 id) | |
2145 | { | |
2146 | struct btf *btf; | |
2147 | int fd; | |
2148 | ||
2149 | rcu_read_lock(); | |
2150 | btf = idr_find(&btf_idr, id); | |
2151 | if (!btf || !refcount_inc_not_zero(&btf->refcnt)) | |
2152 | btf = ERR_PTR(-ENOENT); | |
2153 | rcu_read_unlock(); | |
2154 | ||
2155 | if (IS_ERR(btf)) | |
2156 | return PTR_ERR(btf); | |
2157 | ||
2158 | fd = __btf_new_fd(btf); | |
2159 | if (fd < 0) | |
2160 | btf_put(btf); | |
2161 | ||
2162 | return fd; | |
2163 | } | |
2164 | ||
2165 | u32 btf_id(const struct btf *btf) | |
2166 | { | |
2167 | return btf->id; | |
2168 | } |