1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* Copyright (c) 2018 Facebook */ 3 4 #include <uapi/linux/btf.h> 5 #include <uapi/linux/bpf.h> 6 #include <uapi/linux/bpf_perf_event.h> 7 #include <uapi/linux/types.h> 8 #include <linux/seq_file.h> 9 #include <linux/compiler.h> 10 #include <linux/ctype.h> 11 #include <linux/errno.h> 12 #include <linux/slab.h> 13 #include <linux/anon_inodes.h> 14 #include <linux/file.h> 15 #include <linux/uaccess.h> 16 #include <linux/kernel.h> 17 #include <linux/idr.h> 18 #include <linux/sort.h> 19 #include <linux/bpf_verifier.h> 20 #include <linux/btf.h> 21 #include <linux/btf_ids.h> 22 #include <linux/skmsg.h> 23 #include <linux/perf_event.h> 24 #include <linux/bsearch.h> 25 #include <linux/kobject.h> 26 #include <linux/sysfs.h> 27 #include <net/sock.h> 28 29 /* BTF (BPF Type Format) is the meta data format which describes 30 * the data types of BPF program/map. Hence, it basically focus 31 * on the C programming language which the modern BPF is primary 32 * using. 33 * 34 * ELF Section: 35 * ~~~~~~~~~~~ 36 * The BTF data is stored under the ".BTF" ELF section 37 * 38 * struct btf_type: 39 * ~~~~~~~~~~~~~~~ 40 * Each 'struct btf_type' object describes a C data type. 41 * Depending on the type it is describing, a 'struct btf_type' 42 * object may be followed by more data. F.e. 43 * To describe an array, 'struct btf_type' is followed by 44 * 'struct btf_array'. 45 * 46 * 'struct btf_type' and any extra data following it are 47 * 4 bytes aligned. 48 * 49 * Type section: 50 * ~~~~~~~~~~~~~ 51 * The BTF type section contains a list of 'struct btf_type' objects. 52 * Each one describes a C type. Recall from the above section 53 * that a 'struct btf_type' object could be immediately followed by extra 54 * data in order to describe some particular C types. 55 * 56 * type_id: 57 * ~~~~~~~ 58 * Each btf_type object is identified by a type_id. The type_id 59 * is implicitly implied by the location of the btf_type object in 60 * the BTF type section. The first one has type_id 1. The second 61 * one has type_id 2...etc. Hence, an earlier btf_type has 62 * a smaller type_id. 63 * 64 * A btf_type object may refer to another btf_type object by using 65 * type_id (i.e. the "type" in the "struct btf_type"). 66 * 67 * NOTE that we cannot assume any reference-order. 68 * A btf_type object can refer to an earlier btf_type object 69 * but it can also refer to a later btf_type object. 70 * 71 * For example, to describe "const void *". A btf_type 72 * object describing "const" may refer to another btf_type 73 * object describing "void *". This type-reference is done 74 * by specifying type_id: 75 * 76 * [1] CONST (anon) type_id=2 77 * [2] PTR (anon) type_id=0 78 * 79 * The above is the btf_verifier debug log: 80 * - Each line started with "[?]" is a btf_type object 81 * - [?] is the type_id of the btf_type object. 82 * - CONST/PTR is the BTF_KIND_XXX 83 * - "(anon)" is the name of the type. It just 84 * happens that CONST and PTR has no name. 85 * - type_id=XXX is the 'u32 type' in btf_type 86 * 87 * NOTE: "void" has type_id 0 88 * 89 * String section: 90 * ~~~~~~~~~~~~~~ 91 * The BTF string section contains the names used by the type section. 92 * Each string is referred by an "offset" from the beginning of the 93 * string section. 94 * 95 * Each string is '\0' terminated. 96 * 97 * The first character in the string section must be '\0' 98 * which is used to mean 'anonymous'. Some btf_type may not 99 * have a name. 100 */ 101 102 /* BTF verification: 103 * 104 * To verify BTF data, two passes are needed. 105 * 106 * Pass #1 107 * ~~~~~~~ 108 * The first pass is to collect all btf_type objects to 109 * an array: "btf->types". 110 * 111 * Depending on the C type that a btf_type is describing, 112 * a btf_type may be followed by extra data. We don't know 113 * how many btf_type is there, and more importantly we don't 114 * know where each btf_type is located in the type section. 115 * 116 * Without knowing the location of each type_id, most verifications 117 * cannot be done. e.g. an earlier btf_type may refer to a later 118 * btf_type (recall the "const void *" above), so we cannot 119 * check this type-reference in the first pass. 120 * 121 * In the first pass, it still does some verifications (e.g. 122 * checking the name is a valid offset to the string section). 123 * 124 * Pass #2 125 * ~~~~~~~ 126 * The main focus is to resolve a btf_type that is referring 127 * to another type. 128 * 129 * We have to ensure the referring type: 130 * 1) does exist in the BTF (i.e. in btf->types[]) 131 * 2) does not cause a loop: 132 * struct A { 133 * struct B b; 134 * }; 135 * 136 * struct B { 137 * struct A a; 138 * }; 139 * 140 * btf_type_needs_resolve() decides if a btf_type needs 141 * to be resolved. 142 * 143 * The needs_resolve type implements the "resolve()" ops which 144 * essentially does a DFS and detects backedge. 145 * 146 * During resolve (or DFS), different C types have different 147 * "RESOLVED" conditions. 148 * 149 * When resolving a BTF_KIND_STRUCT, we need to resolve all its 150 * members because a member is always referring to another 151 * type. A struct's member can be treated as "RESOLVED" if 152 * it is referring to a BTF_KIND_PTR. Otherwise, the 153 * following valid C struct would be rejected: 154 * 155 * struct A { 156 * int m; 157 * struct A *a; 158 * }; 159 * 160 * When resolving a BTF_KIND_PTR, it needs to keep resolving if 161 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot 162 * detect a pointer loop, e.g.: 163 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR + 164 * ^ | 165 * +-----------------------------------------+ 166 * 167 */ 168 169 #define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2) 170 #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1) 171 #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK) 172 #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3) 173 #define BITS_ROUNDUP_BYTES(bits) \ 174 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits)) 175 176 #define BTF_INFO_MASK 0x9f00ffff 177 #define BTF_INT_MASK 0x0fffffff 178 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE) 179 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET) 180 181 /* 16MB for 64k structs and each has 16 members and 182 * a few MB spaces for the string section. 183 * The hard limit is S32_MAX. 184 */ 185 #define BTF_MAX_SIZE (16 * 1024 * 1024) 186 187 #define for_each_member_from(i, from, struct_type, member) \ 188 for (i = from, member = btf_type_member(struct_type) + from; \ 189 i < btf_type_vlen(struct_type); \ 190 i++, member++) 191 192 #define for_each_vsi_from(i, from, struct_type, member) \ 193 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \ 194 i < btf_type_vlen(struct_type); \ 195 i++, member++) 196 197 DEFINE_IDR(btf_idr); 198 DEFINE_SPINLOCK(btf_idr_lock); 199 200 struct btf { 201 void *data; 202 struct btf_type **types; 203 u32 *resolved_ids; 204 u32 *resolved_sizes; 205 const char *strings; 206 void *nohdr_data; 207 struct btf_header hdr; 208 u32 nr_types; /* includes VOID for base BTF */ 209 u32 types_size; 210 u32 data_size; 211 refcount_t refcnt; 212 u32 id; 213 struct rcu_head rcu; 214 215 /* split BTF support */ 216 struct btf *base_btf; 217 u32 start_id; /* first type ID in this BTF (0 for base BTF) */ 218 u32 start_str_off; /* first string offset (0 for base BTF) */ 219 char name[MODULE_NAME_LEN]; 220 bool kernel_btf; 221 }; 222 223 enum verifier_phase { 224 CHECK_META, 225 CHECK_TYPE, 226 }; 227 228 struct resolve_vertex { 229 const struct btf_type *t; 230 u32 type_id; 231 u16 next_member; 232 }; 233 234 enum visit_state { 235 NOT_VISITED, 236 VISITED, 237 RESOLVED, 238 }; 239 240 enum resolve_mode { 241 RESOLVE_TBD, /* To Be Determined */ 242 RESOLVE_PTR, /* Resolving for Pointer */ 243 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union 244 * or array 245 */ 246 }; 247 248 #define MAX_RESOLVE_DEPTH 32 249 250 struct btf_sec_info { 251 u32 off; 252 u32 len; 253 }; 254 255 struct btf_verifier_env { 256 struct btf *btf; 257 u8 *visit_states; 258 struct resolve_vertex stack[MAX_RESOLVE_DEPTH]; 259 struct bpf_verifier_log log; 260 u32 log_type_id; 261 u32 top_stack; 262 enum verifier_phase phase; 263 enum resolve_mode resolve_mode; 264 }; 265 266 static const char * const btf_kind_str[NR_BTF_KINDS] = { 267 [BTF_KIND_UNKN] = "UNKNOWN", 268 [BTF_KIND_INT] = "INT", 269 [BTF_KIND_PTR] = "PTR", 270 [BTF_KIND_ARRAY] = "ARRAY", 271 [BTF_KIND_STRUCT] = "STRUCT", 272 [BTF_KIND_UNION] = "UNION", 273 [BTF_KIND_ENUM] = "ENUM", 274 [BTF_KIND_FWD] = "FWD", 275 [BTF_KIND_TYPEDEF] = "TYPEDEF", 276 [BTF_KIND_VOLATILE] = "VOLATILE", 277 [BTF_KIND_CONST] = "CONST", 278 [BTF_KIND_RESTRICT] = "RESTRICT", 279 [BTF_KIND_FUNC] = "FUNC", 280 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO", 281 [BTF_KIND_VAR] = "VAR", 282 [BTF_KIND_DATASEC] = "DATASEC", 283 [BTF_KIND_FLOAT] = "FLOAT", 284 }; 285 286 const char *btf_type_str(const struct btf_type *t) 287 { 288 return btf_kind_str[BTF_INFO_KIND(t->info)]; 289 } 290 291 /* Chunk size we use in safe copy of data to be shown. */ 292 #define BTF_SHOW_OBJ_SAFE_SIZE 32 293 294 /* 295 * This is the maximum size of a base type value (equivalent to a 296 * 128-bit int); if we are at the end of our safe buffer and have 297 * less than 16 bytes space we can't be assured of being able 298 * to copy the next type safely, so in such cases we will initiate 299 * a new copy. 300 */ 301 #define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16 302 303 /* Type name size */ 304 #define BTF_SHOW_NAME_SIZE 80 305 306 /* 307 * Common data to all BTF show operations. Private show functions can add 308 * their own data to a structure containing a struct btf_show and consult it 309 * in the show callback. See btf_type_show() below. 310 * 311 * One challenge with showing nested data is we want to skip 0-valued 312 * data, but in order to figure out whether a nested object is all zeros 313 * we need to walk through it. As a result, we need to make two passes 314 * when handling structs, unions and arrays; the first path simply looks 315 * for nonzero data, while the second actually does the display. The first 316 * pass is signalled by show->state.depth_check being set, and if we 317 * encounter a non-zero value we set show->state.depth_to_show to 318 * the depth at which we encountered it. When we have completed the 319 * first pass, we will know if anything needs to be displayed if 320 * depth_to_show > depth. See btf_[struct,array]_show() for the 321 * implementation of this. 322 * 323 * Another problem is we want to ensure the data for display is safe to 324 * access. To support this, the anonymous "struct {} obj" tracks the data 325 * object and our safe copy of it. We copy portions of the data needed 326 * to the object "copy" buffer, but because its size is limited to 327 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we 328 * traverse larger objects for display. 329 * 330 * The various data type show functions all start with a call to 331 * btf_show_start_type() which returns a pointer to the safe copy 332 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the 333 * raw data itself). btf_show_obj_safe() is responsible for 334 * using copy_from_kernel_nofault() to update the safe data if necessary 335 * as we traverse the object's data. skbuff-like semantics are 336 * used: 337 * 338 * - obj.head points to the start of the toplevel object for display 339 * - obj.size is the size of the toplevel object 340 * - obj.data points to the current point in the original data at 341 * which our safe data starts. obj.data will advance as we copy 342 * portions of the data. 343 * 344 * In most cases a single copy will suffice, but larger data structures 345 * such as "struct task_struct" will require many copies. The logic in 346 * btf_show_obj_safe() handles the logic that determines if a new 347 * copy_from_kernel_nofault() is needed. 348 */ 349 struct btf_show { 350 u64 flags; 351 void *target; /* target of show operation (seq file, buffer) */ 352 void (*showfn)(struct btf_show *show, const char *fmt, va_list args); 353 const struct btf *btf; 354 /* below are used during iteration */ 355 struct { 356 u8 depth; 357 u8 depth_to_show; 358 u8 depth_check; 359 u8 array_member:1, 360 array_terminated:1; 361 u16 array_encoding; 362 u32 type_id; 363 int status; /* non-zero for error */ 364 const struct btf_type *type; 365 const struct btf_member *member; 366 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */ 367 } state; 368 struct { 369 u32 size; 370 void *head; 371 void *data; 372 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE]; 373 } obj; 374 }; 375 376 struct btf_kind_operations { 377 s32 (*check_meta)(struct btf_verifier_env *env, 378 const struct btf_type *t, 379 u32 meta_left); 380 int (*resolve)(struct btf_verifier_env *env, 381 const struct resolve_vertex *v); 382 int (*check_member)(struct btf_verifier_env *env, 383 const struct btf_type *struct_type, 384 const struct btf_member *member, 385 const struct btf_type *member_type); 386 int (*check_kflag_member)(struct btf_verifier_env *env, 387 const struct btf_type *struct_type, 388 const struct btf_member *member, 389 const struct btf_type *member_type); 390 void (*log_details)(struct btf_verifier_env *env, 391 const struct btf_type *t); 392 void (*show)(const struct btf *btf, const struct btf_type *t, 393 u32 type_id, void *data, u8 bits_offsets, 394 struct btf_show *show); 395 }; 396 397 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS]; 398 static struct btf_type btf_void; 399 400 static int btf_resolve(struct btf_verifier_env *env, 401 const struct btf_type *t, u32 type_id); 402 403 static bool btf_type_is_modifier(const struct btf_type *t) 404 { 405 /* Some of them is not strictly a C modifier 406 * but they are grouped into the same bucket 407 * for BTF concern: 408 * A type (t) that refers to another 409 * type through t->type AND its size cannot 410 * be determined without following the t->type. 411 * 412 * ptr does not fall into this bucket 413 * because its size is always sizeof(void *). 414 */ 415 switch (BTF_INFO_KIND(t->info)) { 416 case BTF_KIND_TYPEDEF: 417 case BTF_KIND_VOLATILE: 418 case BTF_KIND_CONST: 419 case BTF_KIND_RESTRICT: 420 return true; 421 } 422 423 return false; 424 } 425 426 bool btf_type_is_void(const struct btf_type *t) 427 { 428 return t == &btf_void; 429 } 430 431 static bool btf_type_is_fwd(const struct btf_type *t) 432 { 433 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD; 434 } 435 436 static bool btf_type_nosize(const struct btf_type *t) 437 { 438 return btf_type_is_void(t) || btf_type_is_fwd(t) || 439 btf_type_is_func(t) || btf_type_is_func_proto(t); 440 } 441 442 static bool btf_type_nosize_or_null(const struct btf_type *t) 443 { 444 return !t || btf_type_nosize(t); 445 } 446 447 static bool __btf_type_is_struct(const struct btf_type *t) 448 { 449 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT; 450 } 451 452 static bool btf_type_is_array(const struct btf_type *t) 453 { 454 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY; 455 } 456 457 static bool btf_type_is_datasec(const struct btf_type *t) 458 { 459 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC; 460 } 461 462 u32 btf_nr_types(const struct btf *btf) 463 { 464 u32 total = 0; 465 466 while (btf) { 467 total += btf->nr_types; 468 btf = btf->base_btf; 469 } 470 471 return total; 472 } 473 474 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind) 475 { 476 const struct btf_type *t; 477 const char *tname; 478 u32 i, total; 479 480 total = btf_nr_types(btf); 481 for (i = 1; i < total; i++) { 482 t = btf_type_by_id(btf, i); 483 if (BTF_INFO_KIND(t->info) != kind) 484 continue; 485 486 tname = btf_name_by_offset(btf, t->name_off); 487 if (!strcmp(tname, name)) 488 return i; 489 } 490 491 return -ENOENT; 492 } 493 494 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf, 495 u32 id, u32 *res_id) 496 { 497 const struct btf_type *t = btf_type_by_id(btf, id); 498 499 while (btf_type_is_modifier(t)) { 500 id = t->type; 501 t = btf_type_by_id(btf, t->type); 502 } 503 504 if (res_id) 505 *res_id = id; 506 507 return t; 508 } 509 510 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf, 511 u32 id, u32 *res_id) 512 { 513 const struct btf_type *t; 514 515 t = btf_type_skip_modifiers(btf, id, NULL); 516 if (!btf_type_is_ptr(t)) 517 return NULL; 518 519 return btf_type_skip_modifiers(btf, t->type, res_id); 520 } 521 522 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf, 523 u32 id, u32 *res_id) 524 { 525 const struct btf_type *ptype; 526 527 ptype = btf_type_resolve_ptr(btf, id, res_id); 528 if (ptype && btf_type_is_func_proto(ptype)) 529 return ptype; 530 531 return NULL; 532 } 533 534 /* Types that act only as a source, not sink or intermediate 535 * type when resolving. 536 */ 537 static bool btf_type_is_resolve_source_only(const struct btf_type *t) 538 { 539 return btf_type_is_var(t) || 540 btf_type_is_datasec(t); 541 } 542 543 /* What types need to be resolved? 544 * 545 * btf_type_is_modifier() is an obvious one. 546 * 547 * btf_type_is_struct() because its member refers to 548 * another type (through member->type). 549 * 550 * btf_type_is_var() because the variable refers to 551 * another type. btf_type_is_datasec() holds multiple 552 * btf_type_is_var() types that need resolving. 553 * 554 * btf_type_is_array() because its element (array->type) 555 * refers to another type. Array can be thought of a 556 * special case of struct while array just has the same 557 * member-type repeated by array->nelems of times. 558 */ 559 static bool btf_type_needs_resolve(const struct btf_type *t) 560 { 561 return btf_type_is_modifier(t) || 562 btf_type_is_ptr(t) || 563 btf_type_is_struct(t) || 564 btf_type_is_array(t) || 565 btf_type_is_var(t) || 566 btf_type_is_datasec(t); 567 } 568 569 /* t->size can be used */ 570 static bool btf_type_has_size(const struct btf_type *t) 571 { 572 switch (BTF_INFO_KIND(t->info)) { 573 case BTF_KIND_INT: 574 case BTF_KIND_STRUCT: 575 case BTF_KIND_UNION: 576 case BTF_KIND_ENUM: 577 case BTF_KIND_DATASEC: 578 case BTF_KIND_FLOAT: 579 return true; 580 } 581 582 return false; 583 } 584 585 static const char *btf_int_encoding_str(u8 encoding) 586 { 587 if (encoding == 0) 588 return "(none)"; 589 else if (encoding == BTF_INT_SIGNED) 590 return "SIGNED"; 591 else if (encoding == BTF_INT_CHAR) 592 return "CHAR"; 593 else if (encoding == BTF_INT_BOOL) 594 return "BOOL"; 595 else 596 return "UNKN"; 597 } 598 599 static u32 btf_type_int(const struct btf_type *t) 600 { 601 return *(u32 *)(t + 1); 602 } 603 604 static const struct btf_array *btf_type_array(const struct btf_type *t) 605 { 606 return (const struct btf_array *)(t + 1); 607 } 608 609 static const struct btf_enum *btf_type_enum(const struct btf_type *t) 610 { 611 return (const struct btf_enum *)(t + 1); 612 } 613 614 static const struct btf_var *btf_type_var(const struct btf_type *t) 615 { 616 return (const struct btf_var *)(t + 1); 617 } 618 619 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t) 620 { 621 return kind_ops[BTF_INFO_KIND(t->info)]; 622 } 623 624 static bool btf_name_offset_valid(const struct btf *btf, u32 offset) 625 { 626 if (!BTF_STR_OFFSET_VALID(offset)) 627 return false; 628 629 while (offset < btf->start_str_off) 630 btf = btf->base_btf; 631 632 offset -= btf->start_str_off; 633 return offset < btf->hdr.str_len; 634 } 635 636 static bool __btf_name_char_ok(char c, bool first, bool dot_ok) 637 { 638 if ((first ? !isalpha(c) : 639 !isalnum(c)) && 640 c != '_' && 641 ((c == '.' && !dot_ok) || 642 c != '.')) 643 return false; 644 return true; 645 } 646 647 static const char *btf_str_by_offset(const struct btf *btf, u32 offset) 648 { 649 while (offset < btf->start_str_off) 650 btf = btf->base_btf; 651 652 offset -= btf->start_str_off; 653 if (offset < btf->hdr.str_len) 654 return &btf->strings[offset]; 655 656 return NULL; 657 } 658 659 static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok) 660 { 661 /* offset must be valid */ 662 const char *src = btf_str_by_offset(btf, offset); 663 const char *src_limit; 664 665 if (!__btf_name_char_ok(*src, true, dot_ok)) 666 return false; 667 668 /* set a limit on identifier length */ 669 src_limit = src + KSYM_NAME_LEN; 670 src++; 671 while (*src && src < src_limit) { 672 if (!__btf_name_char_ok(*src, false, dot_ok)) 673 return false; 674 src++; 675 } 676 677 return !*src; 678 } 679 680 /* Only C-style identifier is permitted. This can be relaxed if 681 * necessary. 682 */ 683 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset) 684 { 685 return __btf_name_valid(btf, offset, false); 686 } 687 688 static bool btf_name_valid_section(const struct btf *btf, u32 offset) 689 { 690 return __btf_name_valid(btf, offset, true); 691 } 692 693 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset) 694 { 695 const char *name; 696 697 if (!offset) 698 return "(anon)"; 699 700 name = btf_str_by_offset(btf, offset); 701 return name ?: "(invalid-name-offset)"; 702 } 703 704 const char *btf_name_by_offset(const struct btf *btf, u32 offset) 705 { 706 return btf_str_by_offset(btf, offset); 707 } 708 709 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) 710 { 711 while (type_id < btf->start_id) 712 btf = btf->base_btf; 713 714 type_id -= btf->start_id; 715 if (type_id >= btf->nr_types) 716 return NULL; 717 return btf->types[type_id]; 718 } 719 720 /* 721 * Regular int is not a bit field and it must be either 722 * u8/u16/u32/u64 or __int128. 723 */ 724 static bool btf_type_int_is_regular(const struct btf_type *t) 725 { 726 u8 nr_bits, nr_bytes; 727 u32 int_data; 728 729 int_data = btf_type_int(t); 730 nr_bits = BTF_INT_BITS(int_data); 731 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits); 732 if (BITS_PER_BYTE_MASKED(nr_bits) || 733 BTF_INT_OFFSET(int_data) || 734 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) && 735 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) && 736 nr_bytes != (2 * sizeof(u64)))) { 737 return false; 738 } 739 740 return true; 741 } 742 743 /* 744 * Check that given struct member is a regular int with expected 745 * offset and size. 746 */ 747 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s, 748 const struct btf_member *m, 749 u32 expected_offset, u32 expected_size) 750 { 751 const struct btf_type *t; 752 u32 id, int_data; 753 u8 nr_bits; 754 755 id = m->type; 756 t = btf_type_id_size(btf, &id, NULL); 757 if (!t || !btf_type_is_int(t)) 758 return false; 759 760 int_data = btf_type_int(t); 761 nr_bits = BTF_INT_BITS(int_data); 762 if (btf_type_kflag(s)) { 763 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset); 764 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset); 765 766 /* if kflag set, int should be a regular int and 767 * bit offset should be at byte boundary. 768 */ 769 return !bitfield_size && 770 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset && 771 BITS_ROUNDUP_BYTES(nr_bits) == expected_size; 772 } 773 774 if (BTF_INT_OFFSET(int_data) || 775 BITS_PER_BYTE_MASKED(m->offset) || 776 BITS_ROUNDUP_BYTES(m->offset) != expected_offset || 777 BITS_PER_BYTE_MASKED(nr_bits) || 778 BITS_ROUNDUP_BYTES(nr_bits) != expected_size) 779 return false; 780 781 return true; 782 } 783 784 /* Similar to btf_type_skip_modifiers() but does not skip typedefs. */ 785 static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf, 786 u32 id) 787 { 788 const struct btf_type *t = btf_type_by_id(btf, id); 789 790 while (btf_type_is_modifier(t) && 791 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) { 792 t = btf_type_by_id(btf, t->type); 793 } 794 795 return t; 796 } 797 798 #define BTF_SHOW_MAX_ITER 10 799 800 #define BTF_KIND_BIT(kind) (1ULL << kind) 801 802 /* 803 * Populate show->state.name with type name information. 804 * Format of type name is 805 * 806 * [.member_name = ] (type_name) 807 */ 808 static const char *btf_show_name(struct btf_show *show) 809 { 810 /* BTF_MAX_ITER array suffixes "[]" */ 811 const char *array_suffixes = "[][][][][][][][][][]"; 812 const char *array_suffix = &array_suffixes[strlen(array_suffixes)]; 813 /* BTF_MAX_ITER pointer suffixes "*" */ 814 const char *ptr_suffixes = "**********"; 815 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)]; 816 const char *name = NULL, *prefix = "", *parens = ""; 817 const struct btf_member *m = show->state.member; 818 const struct btf_type *t = show->state.type; 819 const struct btf_array *array; 820 u32 id = show->state.type_id; 821 const char *member = NULL; 822 bool show_member = false; 823 u64 kinds = 0; 824 int i; 825 826 show->state.name[0] = '\0'; 827 828 /* 829 * Don't show type name if we're showing an array member; 830 * in that case we show the array type so don't need to repeat 831 * ourselves for each member. 832 */ 833 if (show->state.array_member) 834 return ""; 835 836 /* Retrieve member name, if any. */ 837 if (m) { 838 member = btf_name_by_offset(show->btf, m->name_off); 839 show_member = strlen(member) > 0; 840 id = m->type; 841 } 842 843 /* 844 * Start with type_id, as we have resolved the struct btf_type * 845 * via btf_modifier_show() past the parent typedef to the child 846 * struct, int etc it is defined as. In such cases, the type_id 847 * still represents the starting type while the struct btf_type * 848 * in our show->state points at the resolved type of the typedef. 849 */ 850 t = btf_type_by_id(show->btf, id); 851 if (!t) 852 return ""; 853 854 /* 855 * The goal here is to build up the right number of pointer and 856 * array suffixes while ensuring the type name for a typedef 857 * is represented. Along the way we accumulate a list of 858 * BTF kinds we have encountered, since these will inform later 859 * display; for example, pointer types will not require an 860 * opening "{" for struct, we will just display the pointer value. 861 * 862 * We also want to accumulate the right number of pointer or array 863 * indices in the format string while iterating until we get to 864 * the typedef/pointee/array member target type. 865 * 866 * We start by pointing at the end of pointer and array suffix 867 * strings; as we accumulate pointers and arrays we move the pointer 868 * or array string backwards so it will show the expected number of 869 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers 870 * and/or arrays and typedefs are supported as a precaution. 871 * 872 * We also want to get typedef name while proceeding to resolve 873 * type it points to so that we can add parentheses if it is a 874 * "typedef struct" etc. 875 */ 876 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) { 877 878 switch (BTF_INFO_KIND(t->info)) { 879 case BTF_KIND_TYPEDEF: 880 if (!name) 881 name = btf_name_by_offset(show->btf, 882 t->name_off); 883 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF); 884 id = t->type; 885 break; 886 case BTF_KIND_ARRAY: 887 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY); 888 parens = "["; 889 if (!t) 890 return ""; 891 array = btf_type_array(t); 892 if (array_suffix > array_suffixes) 893 array_suffix -= 2; 894 id = array->type; 895 break; 896 case BTF_KIND_PTR: 897 kinds |= BTF_KIND_BIT(BTF_KIND_PTR); 898 if (ptr_suffix > ptr_suffixes) 899 ptr_suffix -= 1; 900 id = t->type; 901 break; 902 default: 903 id = 0; 904 break; 905 } 906 if (!id) 907 break; 908 t = btf_type_skip_qualifiers(show->btf, id); 909 } 910 /* We may not be able to represent this type; bail to be safe */ 911 if (i == BTF_SHOW_MAX_ITER) 912 return ""; 913 914 if (!name) 915 name = btf_name_by_offset(show->btf, t->name_off); 916 917 switch (BTF_INFO_KIND(t->info)) { 918 case BTF_KIND_STRUCT: 919 case BTF_KIND_UNION: 920 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ? 921 "struct" : "union"; 922 /* if it's an array of struct/union, parens is already set */ 923 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY)))) 924 parens = "{"; 925 break; 926 case BTF_KIND_ENUM: 927 prefix = "enum"; 928 break; 929 default: 930 break; 931 } 932 933 /* pointer does not require parens */ 934 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR)) 935 parens = ""; 936 /* typedef does not require struct/union/enum prefix */ 937 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF)) 938 prefix = ""; 939 940 if (!name) 941 name = ""; 942 943 /* Even if we don't want type name info, we want parentheses etc */ 944 if (show->flags & BTF_SHOW_NONAME) 945 snprintf(show->state.name, sizeof(show->state.name), "%s", 946 parens); 947 else 948 snprintf(show->state.name, sizeof(show->state.name), 949 "%s%s%s(%s%s%s%s%s%s)%s", 950 /* first 3 strings comprise ".member = " */ 951 show_member ? "." : "", 952 show_member ? member : "", 953 show_member ? " = " : "", 954 /* ...next is our prefix (struct, enum, etc) */ 955 prefix, 956 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "", 957 /* ...this is the type name itself */ 958 name, 959 /* ...suffixed by the appropriate '*', '[]' suffixes */ 960 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix, 961 array_suffix, parens); 962 963 return show->state.name; 964 } 965 966 static const char *__btf_show_indent(struct btf_show *show) 967 { 968 const char *indents = " "; 969 const char *indent = &indents[strlen(indents)]; 970 971 if ((indent - show->state.depth) >= indents) 972 return indent - show->state.depth; 973 return indents; 974 } 975 976 static const char *btf_show_indent(struct btf_show *show) 977 { 978 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show); 979 } 980 981 static const char *btf_show_newline(struct btf_show *show) 982 { 983 return show->flags & BTF_SHOW_COMPACT ? "" : "\n"; 984 } 985 986 static const char *btf_show_delim(struct btf_show *show) 987 { 988 if (show->state.depth == 0) 989 return ""; 990 991 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type && 992 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION) 993 return "|"; 994 995 return ","; 996 } 997 998 __printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...) 999 { 1000 va_list args; 1001 1002 if (!show->state.depth_check) { 1003 va_start(args, fmt); 1004 show->showfn(show, fmt, args); 1005 va_end(args); 1006 } 1007 } 1008 1009 /* Macros are used here as btf_show_type_value[s]() prepends and appends 1010 * format specifiers to the format specifier passed in; these do the work of 1011 * adding indentation, delimiters etc while the caller simply has to specify 1012 * the type value(s) in the format specifier + value(s). 1013 */ 1014 #define btf_show_type_value(show, fmt, value) \ 1015 do { \ 1016 if ((value) != 0 || (show->flags & BTF_SHOW_ZERO) || \ 1017 show->state.depth == 0) { \ 1018 btf_show(show, "%s%s" fmt "%s%s", \ 1019 btf_show_indent(show), \ 1020 btf_show_name(show), \ 1021 value, btf_show_delim(show), \ 1022 btf_show_newline(show)); \ 1023 if (show->state.depth > show->state.depth_to_show) \ 1024 show->state.depth_to_show = show->state.depth; \ 1025 } \ 1026 } while (0) 1027 1028 #define btf_show_type_values(show, fmt, ...) \ 1029 do { \ 1030 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \ 1031 btf_show_name(show), \ 1032 __VA_ARGS__, btf_show_delim(show), \ 1033 btf_show_newline(show)); \ 1034 if (show->state.depth > show->state.depth_to_show) \ 1035 show->state.depth_to_show = show->state.depth; \ 1036 } while (0) 1037 1038 /* How much is left to copy to safe buffer after @data? */ 1039 static int btf_show_obj_size_left(struct btf_show *show, void *data) 1040 { 1041 return show->obj.head + show->obj.size - data; 1042 } 1043 1044 /* Is object pointed to by @data of @size already copied to our safe buffer? */ 1045 static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size) 1046 { 1047 return data >= show->obj.data && 1048 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE); 1049 } 1050 1051 /* 1052 * If object pointed to by @data of @size falls within our safe buffer, return 1053 * the equivalent pointer to the same safe data. Assumes 1054 * copy_from_kernel_nofault() has already happened and our safe buffer is 1055 * populated. 1056 */ 1057 static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size) 1058 { 1059 if (btf_show_obj_is_safe(show, data, size)) 1060 return show->obj.safe + (data - show->obj.data); 1061 return NULL; 1062 } 1063 1064 /* 1065 * Return a safe-to-access version of data pointed to by @data. 1066 * We do this by copying the relevant amount of information 1067 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault(). 1068 * 1069 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no 1070 * safe copy is needed. 1071 * 1072 * Otherwise we need to determine if we have the required amount 1073 * of data (determined by the @data pointer and the size of the 1074 * largest base type we can encounter (represented by 1075 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures 1076 * that we will be able to print some of the current object, 1077 * and if more is needed a copy will be triggered. 1078 * Some objects such as structs will not fit into the buffer; 1079 * in such cases additional copies when we iterate over their 1080 * members may be needed. 1081 * 1082 * btf_show_obj_safe() is used to return a safe buffer for 1083 * btf_show_start_type(); this ensures that as we recurse into 1084 * nested types we always have safe data for the given type. 1085 * This approach is somewhat wasteful; it's possible for example 1086 * that when iterating over a large union we'll end up copying the 1087 * same data repeatedly, but the goal is safety not performance. 1088 * We use stack data as opposed to per-CPU buffers because the 1089 * iteration over a type can take some time, and preemption handling 1090 * would greatly complicate use of the safe buffer. 1091 */ 1092 static void *btf_show_obj_safe(struct btf_show *show, 1093 const struct btf_type *t, 1094 void *data) 1095 { 1096 const struct btf_type *rt; 1097 int size_left, size; 1098 void *safe = NULL; 1099 1100 if (show->flags & BTF_SHOW_UNSAFE) 1101 return data; 1102 1103 rt = btf_resolve_size(show->btf, t, &size); 1104 if (IS_ERR(rt)) { 1105 show->state.status = PTR_ERR(rt); 1106 return NULL; 1107 } 1108 1109 /* 1110 * Is this toplevel object? If so, set total object size and 1111 * initialize pointers. Otherwise check if we still fall within 1112 * our safe object data. 1113 */ 1114 if (show->state.depth == 0) { 1115 show->obj.size = size; 1116 show->obj.head = data; 1117 } else { 1118 /* 1119 * If the size of the current object is > our remaining 1120 * safe buffer we _may_ need to do a new copy. However 1121 * consider the case of a nested struct; it's size pushes 1122 * us over the safe buffer limit, but showing any individual 1123 * struct members does not. In such cases, we don't need 1124 * to initiate a fresh copy yet; however we definitely need 1125 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left 1126 * in our buffer, regardless of the current object size. 1127 * The logic here is that as we resolve types we will 1128 * hit a base type at some point, and we need to be sure 1129 * the next chunk of data is safely available to display 1130 * that type info safely. We cannot rely on the size of 1131 * the current object here because it may be much larger 1132 * than our current buffer (e.g. task_struct is 8k). 1133 * All we want to do here is ensure that we can print the 1134 * next basic type, which we can if either 1135 * - the current type size is within the safe buffer; or 1136 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in 1137 * the safe buffer. 1138 */ 1139 safe = __btf_show_obj_safe(show, data, 1140 min(size, 1141 BTF_SHOW_OBJ_BASE_TYPE_SIZE)); 1142 } 1143 1144 /* 1145 * We need a new copy to our safe object, either because we haven't 1146 * yet copied and are initializing safe data, or because the data 1147 * we want falls outside the boundaries of the safe object. 1148 */ 1149 if (!safe) { 1150 size_left = btf_show_obj_size_left(show, data); 1151 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE) 1152 size_left = BTF_SHOW_OBJ_SAFE_SIZE; 1153 show->state.status = copy_from_kernel_nofault(show->obj.safe, 1154 data, size_left); 1155 if (!show->state.status) { 1156 show->obj.data = data; 1157 safe = show->obj.safe; 1158 } 1159 } 1160 1161 return safe; 1162 } 1163 1164 /* 1165 * Set the type we are starting to show and return a safe data pointer 1166 * to be used for showing the associated data. 1167 */ 1168 static void *btf_show_start_type(struct btf_show *show, 1169 const struct btf_type *t, 1170 u32 type_id, void *data) 1171 { 1172 show->state.type = t; 1173 show->state.type_id = type_id; 1174 show->state.name[0] = '\0'; 1175 1176 return btf_show_obj_safe(show, t, data); 1177 } 1178 1179 static void btf_show_end_type(struct btf_show *show) 1180 { 1181 show->state.type = NULL; 1182 show->state.type_id = 0; 1183 show->state.name[0] = '\0'; 1184 } 1185 1186 static void *btf_show_start_aggr_type(struct btf_show *show, 1187 const struct btf_type *t, 1188 u32 type_id, void *data) 1189 { 1190 void *safe_data = btf_show_start_type(show, t, type_id, data); 1191 1192 if (!safe_data) 1193 return safe_data; 1194 1195 btf_show(show, "%s%s%s", btf_show_indent(show), 1196 btf_show_name(show), 1197 btf_show_newline(show)); 1198 show->state.depth++; 1199 return safe_data; 1200 } 1201 1202 static void btf_show_end_aggr_type(struct btf_show *show, 1203 const char *suffix) 1204 { 1205 show->state.depth--; 1206 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix, 1207 btf_show_delim(show), btf_show_newline(show)); 1208 btf_show_end_type(show); 1209 } 1210 1211 static void btf_show_start_member(struct btf_show *show, 1212 const struct btf_member *m) 1213 { 1214 show->state.member = m; 1215 } 1216 1217 static void btf_show_start_array_member(struct btf_show *show) 1218 { 1219 show->state.array_member = 1; 1220 btf_show_start_member(show, NULL); 1221 } 1222 1223 static void btf_show_end_member(struct btf_show *show) 1224 { 1225 show->state.member = NULL; 1226 } 1227 1228 static void btf_show_end_array_member(struct btf_show *show) 1229 { 1230 show->state.array_member = 0; 1231 btf_show_end_member(show); 1232 } 1233 1234 static void *btf_show_start_array_type(struct btf_show *show, 1235 const struct btf_type *t, 1236 u32 type_id, 1237 u16 array_encoding, 1238 void *data) 1239 { 1240 show->state.array_encoding = array_encoding; 1241 show->state.array_terminated = 0; 1242 return btf_show_start_aggr_type(show, t, type_id, data); 1243 } 1244 1245 static void btf_show_end_array_type(struct btf_show *show) 1246 { 1247 show->state.array_encoding = 0; 1248 show->state.array_terminated = 0; 1249 btf_show_end_aggr_type(show, "]"); 1250 } 1251 1252 static void *btf_show_start_struct_type(struct btf_show *show, 1253 const struct btf_type *t, 1254 u32 type_id, 1255 void *data) 1256 { 1257 return btf_show_start_aggr_type(show, t, type_id, data); 1258 } 1259 1260 static void btf_show_end_struct_type(struct btf_show *show) 1261 { 1262 btf_show_end_aggr_type(show, "}"); 1263 } 1264 1265 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log, 1266 const char *fmt, ...) 1267 { 1268 va_list args; 1269 1270 va_start(args, fmt); 1271 bpf_verifier_vlog(log, fmt, args); 1272 va_end(args); 1273 } 1274 1275 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env, 1276 const char *fmt, ...) 1277 { 1278 struct bpf_verifier_log *log = &env->log; 1279 va_list args; 1280 1281 if (!bpf_verifier_log_needed(log)) 1282 return; 1283 1284 va_start(args, fmt); 1285 bpf_verifier_vlog(log, fmt, args); 1286 va_end(args); 1287 } 1288 1289 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env, 1290 const struct btf_type *t, 1291 bool log_details, 1292 const char *fmt, ...) 1293 { 1294 struct bpf_verifier_log *log = &env->log; 1295 u8 kind = BTF_INFO_KIND(t->info); 1296 struct btf *btf = env->btf; 1297 va_list args; 1298 1299 if (!bpf_verifier_log_needed(log)) 1300 return; 1301 1302 /* btf verifier prints all types it is processing via 1303 * btf_verifier_log_type(..., fmt = NULL). 1304 * Skip those prints for in-kernel BTF verification. 1305 */ 1306 if (log->level == BPF_LOG_KERNEL && !fmt) 1307 return; 1308 1309 __btf_verifier_log(log, "[%u] %s %s%s", 1310 env->log_type_id, 1311 btf_kind_str[kind], 1312 __btf_name_by_offset(btf, t->name_off), 1313 log_details ? " " : ""); 1314 1315 if (log_details) 1316 btf_type_ops(t)->log_details(env, t); 1317 1318 if (fmt && *fmt) { 1319 __btf_verifier_log(log, " "); 1320 va_start(args, fmt); 1321 bpf_verifier_vlog(log, fmt, args); 1322 va_end(args); 1323 } 1324 1325 __btf_verifier_log(log, "\n"); 1326 } 1327 1328 #define btf_verifier_log_type(env, t, ...) \ 1329 __btf_verifier_log_type((env), (t), true, __VA_ARGS__) 1330 #define btf_verifier_log_basic(env, t, ...) \ 1331 __btf_verifier_log_type((env), (t), false, __VA_ARGS__) 1332 1333 __printf(4, 5) 1334 static void btf_verifier_log_member(struct btf_verifier_env *env, 1335 const struct btf_type *struct_type, 1336 const struct btf_member *member, 1337 const char *fmt, ...) 1338 { 1339 struct bpf_verifier_log *log = &env->log; 1340 struct btf *btf = env->btf; 1341 va_list args; 1342 1343 if (!bpf_verifier_log_needed(log)) 1344 return; 1345 1346 if (log->level == BPF_LOG_KERNEL && !fmt) 1347 return; 1348 /* The CHECK_META phase already did a btf dump. 1349 * 1350 * If member is logged again, it must hit an error in 1351 * parsing this member. It is useful to print out which 1352 * struct this member belongs to. 1353 */ 1354 if (env->phase != CHECK_META) 1355 btf_verifier_log_type(env, struct_type, NULL); 1356 1357 if (btf_type_kflag(struct_type)) 1358 __btf_verifier_log(log, 1359 "\t%s type_id=%u bitfield_size=%u bits_offset=%u", 1360 __btf_name_by_offset(btf, member->name_off), 1361 member->type, 1362 BTF_MEMBER_BITFIELD_SIZE(member->offset), 1363 BTF_MEMBER_BIT_OFFSET(member->offset)); 1364 else 1365 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u", 1366 __btf_name_by_offset(btf, member->name_off), 1367 member->type, member->offset); 1368 1369 if (fmt && *fmt) { 1370 __btf_verifier_log(log, " "); 1371 va_start(args, fmt); 1372 bpf_verifier_vlog(log, fmt, args); 1373 va_end(args); 1374 } 1375 1376 __btf_verifier_log(log, "\n"); 1377 } 1378 1379 __printf(4, 5) 1380 static void btf_verifier_log_vsi(struct btf_verifier_env *env, 1381 const struct btf_type *datasec_type, 1382 const struct btf_var_secinfo *vsi, 1383 const char *fmt, ...) 1384 { 1385 struct bpf_verifier_log *log = &env->log; 1386 va_list args; 1387 1388 if (!bpf_verifier_log_needed(log)) 1389 return; 1390 if (log->level == BPF_LOG_KERNEL && !fmt) 1391 return; 1392 if (env->phase != CHECK_META) 1393 btf_verifier_log_type(env, datasec_type, NULL); 1394 1395 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u", 1396 vsi->type, vsi->offset, vsi->size); 1397 if (fmt && *fmt) { 1398 __btf_verifier_log(log, " "); 1399 va_start(args, fmt); 1400 bpf_verifier_vlog(log, fmt, args); 1401 va_end(args); 1402 } 1403 1404 __btf_verifier_log(log, "\n"); 1405 } 1406 1407 static void btf_verifier_log_hdr(struct btf_verifier_env *env, 1408 u32 btf_data_size) 1409 { 1410 struct bpf_verifier_log *log = &env->log; 1411 const struct btf *btf = env->btf; 1412 const struct btf_header *hdr; 1413 1414 if (!bpf_verifier_log_needed(log)) 1415 return; 1416 1417 if (log->level == BPF_LOG_KERNEL) 1418 return; 1419 hdr = &btf->hdr; 1420 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic); 1421 __btf_verifier_log(log, "version: %u\n", hdr->version); 1422 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags); 1423 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len); 1424 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off); 1425 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len); 1426 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off); 1427 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len); 1428 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size); 1429 } 1430 1431 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t) 1432 { 1433 struct btf *btf = env->btf; 1434 1435 if (btf->types_size == btf->nr_types) { 1436 /* Expand 'types' array */ 1437 1438 struct btf_type **new_types; 1439 u32 expand_by, new_size; 1440 1441 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) { 1442 btf_verifier_log(env, "Exceeded max num of types"); 1443 return -E2BIG; 1444 } 1445 1446 expand_by = max_t(u32, btf->types_size >> 2, 16); 1447 new_size = min_t(u32, BTF_MAX_TYPE, 1448 btf->types_size + expand_by); 1449 1450 new_types = kvcalloc(new_size, sizeof(*new_types), 1451 GFP_KERNEL | __GFP_NOWARN); 1452 if (!new_types) 1453 return -ENOMEM; 1454 1455 if (btf->nr_types == 0) { 1456 if (!btf->base_btf) { 1457 /* lazily init VOID type */ 1458 new_types[0] = &btf_void; 1459 btf->nr_types++; 1460 } 1461 } else { 1462 memcpy(new_types, btf->types, 1463 sizeof(*btf->types) * btf->nr_types); 1464 } 1465 1466 kvfree(btf->types); 1467 btf->types = new_types; 1468 btf->types_size = new_size; 1469 } 1470 1471 btf->types[btf->nr_types++] = t; 1472 1473 return 0; 1474 } 1475 1476 static int btf_alloc_id(struct btf *btf) 1477 { 1478 int id; 1479 1480 idr_preload(GFP_KERNEL); 1481 spin_lock_bh(&btf_idr_lock); 1482 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC); 1483 if (id > 0) 1484 btf->id = id; 1485 spin_unlock_bh(&btf_idr_lock); 1486 idr_preload_end(); 1487 1488 if (WARN_ON_ONCE(!id)) 1489 return -ENOSPC; 1490 1491 return id > 0 ? 0 : id; 1492 } 1493 1494 static void btf_free_id(struct btf *btf) 1495 { 1496 unsigned long flags; 1497 1498 /* 1499 * In map-in-map, calling map_delete_elem() on outer 1500 * map will call bpf_map_put on the inner map. 1501 * It will then eventually call btf_free_id() 1502 * on the inner map. Some of the map_delete_elem() 1503 * implementation may have irq disabled, so 1504 * we need to use the _irqsave() version instead 1505 * of the _bh() version. 1506 */ 1507 spin_lock_irqsave(&btf_idr_lock, flags); 1508 idr_remove(&btf_idr, btf->id); 1509 spin_unlock_irqrestore(&btf_idr_lock, flags); 1510 } 1511 1512 static void btf_free(struct btf *btf) 1513 { 1514 kvfree(btf->types); 1515 kvfree(btf->resolved_sizes); 1516 kvfree(btf->resolved_ids); 1517 kvfree(btf->data); 1518 kfree(btf); 1519 } 1520 1521 static void btf_free_rcu(struct rcu_head *rcu) 1522 { 1523 struct btf *btf = container_of(rcu, struct btf, rcu); 1524 1525 btf_free(btf); 1526 } 1527 1528 void btf_get(struct btf *btf) 1529 { 1530 refcount_inc(&btf->refcnt); 1531 } 1532 1533 void btf_put(struct btf *btf) 1534 { 1535 if (btf && refcount_dec_and_test(&btf->refcnt)) { 1536 btf_free_id(btf); 1537 call_rcu(&btf->rcu, btf_free_rcu); 1538 } 1539 } 1540 1541 static int env_resolve_init(struct btf_verifier_env *env) 1542 { 1543 struct btf *btf = env->btf; 1544 u32 nr_types = btf->nr_types; 1545 u32 *resolved_sizes = NULL; 1546 u32 *resolved_ids = NULL; 1547 u8 *visit_states = NULL; 1548 1549 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes), 1550 GFP_KERNEL | __GFP_NOWARN); 1551 if (!resolved_sizes) 1552 goto nomem; 1553 1554 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids), 1555 GFP_KERNEL | __GFP_NOWARN); 1556 if (!resolved_ids) 1557 goto nomem; 1558 1559 visit_states = kvcalloc(nr_types, sizeof(*visit_states), 1560 GFP_KERNEL | __GFP_NOWARN); 1561 if (!visit_states) 1562 goto nomem; 1563 1564 btf->resolved_sizes = resolved_sizes; 1565 btf->resolved_ids = resolved_ids; 1566 env->visit_states = visit_states; 1567 1568 return 0; 1569 1570 nomem: 1571 kvfree(resolved_sizes); 1572 kvfree(resolved_ids); 1573 kvfree(visit_states); 1574 return -ENOMEM; 1575 } 1576 1577 static void btf_verifier_env_free(struct btf_verifier_env *env) 1578 { 1579 kvfree(env->visit_states); 1580 kfree(env); 1581 } 1582 1583 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env, 1584 const struct btf_type *next_type) 1585 { 1586 switch (env->resolve_mode) { 1587 case RESOLVE_TBD: 1588 /* int, enum or void is a sink */ 1589 return !btf_type_needs_resolve(next_type); 1590 case RESOLVE_PTR: 1591 /* int, enum, void, struct, array, func or func_proto is a sink 1592 * for ptr 1593 */ 1594 return !btf_type_is_modifier(next_type) && 1595 !btf_type_is_ptr(next_type); 1596 case RESOLVE_STRUCT_OR_ARRAY: 1597 /* int, enum, void, ptr, func or func_proto is a sink 1598 * for struct and array 1599 */ 1600 return !btf_type_is_modifier(next_type) && 1601 !btf_type_is_array(next_type) && 1602 !btf_type_is_struct(next_type); 1603 default: 1604 BUG(); 1605 } 1606 } 1607 1608 static bool env_type_is_resolved(const struct btf_verifier_env *env, 1609 u32 type_id) 1610 { 1611 /* base BTF types should be resolved by now */ 1612 if (type_id < env->btf->start_id) 1613 return true; 1614 1615 return env->visit_states[type_id - env->btf->start_id] == RESOLVED; 1616 } 1617 1618 static int env_stack_push(struct btf_verifier_env *env, 1619 const struct btf_type *t, u32 type_id) 1620 { 1621 const struct btf *btf = env->btf; 1622 struct resolve_vertex *v; 1623 1624 if (env->top_stack == MAX_RESOLVE_DEPTH) 1625 return -E2BIG; 1626 1627 if (type_id < btf->start_id 1628 || env->visit_states[type_id - btf->start_id] != NOT_VISITED) 1629 return -EEXIST; 1630 1631 env->visit_states[type_id - btf->start_id] = VISITED; 1632 1633 v = &env->stack[env->top_stack++]; 1634 v->t = t; 1635 v->type_id = type_id; 1636 v->next_member = 0; 1637 1638 if (env->resolve_mode == RESOLVE_TBD) { 1639 if (btf_type_is_ptr(t)) 1640 env->resolve_mode = RESOLVE_PTR; 1641 else if (btf_type_is_struct(t) || btf_type_is_array(t)) 1642 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY; 1643 } 1644 1645 return 0; 1646 } 1647 1648 static void env_stack_set_next_member(struct btf_verifier_env *env, 1649 u16 next_member) 1650 { 1651 env->stack[env->top_stack - 1].next_member = next_member; 1652 } 1653 1654 static void env_stack_pop_resolved(struct btf_verifier_env *env, 1655 u32 resolved_type_id, 1656 u32 resolved_size) 1657 { 1658 u32 type_id = env->stack[--(env->top_stack)].type_id; 1659 struct btf *btf = env->btf; 1660 1661 type_id -= btf->start_id; /* adjust to local type id */ 1662 btf->resolved_sizes[type_id] = resolved_size; 1663 btf->resolved_ids[type_id] = resolved_type_id; 1664 env->visit_states[type_id] = RESOLVED; 1665 } 1666 1667 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env) 1668 { 1669 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL; 1670 } 1671 1672 /* Resolve the size of a passed-in "type" 1673 * 1674 * type: is an array (e.g. u32 array[x][y]) 1675 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY, 1676 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always 1677 * corresponds to the return type. 1678 * *elem_type: u32 1679 * *elem_id: id of u32 1680 * *total_nelems: (x * y). Hence, individual elem size is 1681 * (*type_size / *total_nelems) 1682 * *type_id: id of type if it's changed within the function, 0 if not 1683 * 1684 * type: is not an array (e.g. const struct X) 1685 * return type: type "struct X" 1686 * *type_size: sizeof(struct X) 1687 * *elem_type: same as return type ("struct X") 1688 * *elem_id: 0 1689 * *total_nelems: 1 1690 * *type_id: id of type if it's changed within the function, 0 if not 1691 */ 1692 static const struct btf_type * 1693 __btf_resolve_size(const struct btf *btf, const struct btf_type *type, 1694 u32 *type_size, const struct btf_type **elem_type, 1695 u32 *elem_id, u32 *total_nelems, u32 *type_id) 1696 { 1697 const struct btf_type *array_type = NULL; 1698 const struct btf_array *array = NULL; 1699 u32 i, size, nelems = 1, id = 0; 1700 1701 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) { 1702 switch (BTF_INFO_KIND(type->info)) { 1703 /* type->size can be used */ 1704 case BTF_KIND_INT: 1705 case BTF_KIND_STRUCT: 1706 case BTF_KIND_UNION: 1707 case BTF_KIND_ENUM: 1708 case BTF_KIND_FLOAT: 1709 size = type->size; 1710 goto resolved; 1711 1712 case BTF_KIND_PTR: 1713 size = sizeof(void *); 1714 goto resolved; 1715 1716 /* Modifiers */ 1717 case BTF_KIND_TYPEDEF: 1718 case BTF_KIND_VOLATILE: 1719 case BTF_KIND_CONST: 1720 case BTF_KIND_RESTRICT: 1721 id = type->type; 1722 type = btf_type_by_id(btf, type->type); 1723 break; 1724 1725 case BTF_KIND_ARRAY: 1726 if (!array_type) 1727 array_type = type; 1728 array = btf_type_array(type); 1729 if (nelems && array->nelems > U32_MAX / nelems) 1730 return ERR_PTR(-EINVAL); 1731 nelems *= array->nelems; 1732 type = btf_type_by_id(btf, array->type); 1733 break; 1734 1735 /* type without size */ 1736 default: 1737 return ERR_PTR(-EINVAL); 1738 } 1739 } 1740 1741 return ERR_PTR(-EINVAL); 1742 1743 resolved: 1744 if (nelems && size > U32_MAX / nelems) 1745 return ERR_PTR(-EINVAL); 1746 1747 *type_size = nelems * size; 1748 if (total_nelems) 1749 *total_nelems = nelems; 1750 if (elem_type) 1751 *elem_type = type; 1752 if (elem_id) 1753 *elem_id = array ? array->type : 0; 1754 if (type_id && id) 1755 *type_id = id; 1756 1757 return array_type ? : type; 1758 } 1759 1760 const struct btf_type * 1761 btf_resolve_size(const struct btf *btf, const struct btf_type *type, 1762 u32 *type_size) 1763 { 1764 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL); 1765 } 1766 1767 static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id) 1768 { 1769 while (type_id < btf->start_id) 1770 btf = btf->base_btf; 1771 1772 return btf->resolved_ids[type_id - btf->start_id]; 1773 } 1774 1775 /* The input param "type_id" must point to a needs_resolve type */ 1776 static const struct btf_type *btf_type_id_resolve(const struct btf *btf, 1777 u32 *type_id) 1778 { 1779 *type_id = btf_resolved_type_id(btf, *type_id); 1780 return btf_type_by_id(btf, *type_id); 1781 } 1782 1783 static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id) 1784 { 1785 while (type_id < btf->start_id) 1786 btf = btf->base_btf; 1787 1788 return btf->resolved_sizes[type_id - btf->start_id]; 1789 } 1790 1791 const struct btf_type *btf_type_id_size(const struct btf *btf, 1792 u32 *type_id, u32 *ret_size) 1793 { 1794 const struct btf_type *size_type; 1795 u32 size_type_id = *type_id; 1796 u32 size = 0; 1797 1798 size_type = btf_type_by_id(btf, size_type_id); 1799 if (btf_type_nosize_or_null(size_type)) 1800 return NULL; 1801 1802 if (btf_type_has_size(size_type)) { 1803 size = size_type->size; 1804 } else if (btf_type_is_array(size_type)) { 1805 size = btf_resolved_type_size(btf, size_type_id); 1806 } else if (btf_type_is_ptr(size_type)) { 1807 size = sizeof(void *); 1808 } else { 1809 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) && 1810 !btf_type_is_var(size_type))) 1811 return NULL; 1812 1813 size_type_id = btf_resolved_type_id(btf, size_type_id); 1814 size_type = btf_type_by_id(btf, size_type_id); 1815 if (btf_type_nosize_or_null(size_type)) 1816 return NULL; 1817 else if (btf_type_has_size(size_type)) 1818 size = size_type->size; 1819 else if (btf_type_is_array(size_type)) 1820 size = btf_resolved_type_size(btf, size_type_id); 1821 else if (btf_type_is_ptr(size_type)) 1822 size = sizeof(void *); 1823 else 1824 return NULL; 1825 } 1826 1827 *type_id = size_type_id; 1828 if (ret_size) 1829 *ret_size = size; 1830 1831 return size_type; 1832 } 1833 1834 static int btf_df_check_member(struct btf_verifier_env *env, 1835 const struct btf_type *struct_type, 1836 const struct btf_member *member, 1837 const struct btf_type *member_type) 1838 { 1839 btf_verifier_log_basic(env, struct_type, 1840 "Unsupported check_member"); 1841 return -EINVAL; 1842 } 1843 1844 static int btf_df_check_kflag_member(struct btf_verifier_env *env, 1845 const struct btf_type *struct_type, 1846 const struct btf_member *member, 1847 const struct btf_type *member_type) 1848 { 1849 btf_verifier_log_basic(env, struct_type, 1850 "Unsupported check_kflag_member"); 1851 return -EINVAL; 1852 } 1853 1854 /* Used for ptr, array struct/union and float type members. 1855 * int, enum and modifier types have their specific callback functions. 1856 */ 1857 static int btf_generic_check_kflag_member(struct btf_verifier_env *env, 1858 const struct btf_type *struct_type, 1859 const struct btf_member *member, 1860 const struct btf_type *member_type) 1861 { 1862 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) { 1863 btf_verifier_log_member(env, struct_type, member, 1864 "Invalid member bitfield_size"); 1865 return -EINVAL; 1866 } 1867 1868 /* bitfield size is 0, so member->offset represents bit offset only. 1869 * It is safe to call non kflag check_member variants. 1870 */ 1871 return btf_type_ops(member_type)->check_member(env, struct_type, 1872 member, 1873 member_type); 1874 } 1875 1876 static int btf_df_resolve(struct btf_verifier_env *env, 1877 const struct resolve_vertex *v) 1878 { 1879 btf_verifier_log_basic(env, v->t, "Unsupported resolve"); 1880 return -EINVAL; 1881 } 1882 1883 static void btf_df_show(const struct btf *btf, const struct btf_type *t, 1884 u32 type_id, void *data, u8 bits_offsets, 1885 struct btf_show *show) 1886 { 1887 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info)); 1888 } 1889 1890 static int btf_int_check_member(struct btf_verifier_env *env, 1891 const struct btf_type *struct_type, 1892 const struct btf_member *member, 1893 const struct btf_type *member_type) 1894 { 1895 u32 int_data = btf_type_int(member_type); 1896 u32 struct_bits_off = member->offset; 1897 u32 struct_size = struct_type->size; 1898 u32 nr_copy_bits; 1899 u32 bytes_offset; 1900 1901 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) { 1902 btf_verifier_log_member(env, struct_type, member, 1903 "bits_offset exceeds U32_MAX"); 1904 return -EINVAL; 1905 } 1906 1907 struct_bits_off += BTF_INT_OFFSET(int_data); 1908 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 1909 nr_copy_bits = BTF_INT_BITS(int_data) + 1910 BITS_PER_BYTE_MASKED(struct_bits_off); 1911 1912 if (nr_copy_bits > BITS_PER_U128) { 1913 btf_verifier_log_member(env, struct_type, member, 1914 "nr_copy_bits exceeds 128"); 1915 return -EINVAL; 1916 } 1917 1918 if (struct_size < bytes_offset || 1919 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) { 1920 btf_verifier_log_member(env, struct_type, member, 1921 "Member exceeds struct_size"); 1922 return -EINVAL; 1923 } 1924 1925 return 0; 1926 } 1927 1928 static int btf_int_check_kflag_member(struct btf_verifier_env *env, 1929 const struct btf_type *struct_type, 1930 const struct btf_member *member, 1931 const struct btf_type *member_type) 1932 { 1933 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset; 1934 u32 int_data = btf_type_int(member_type); 1935 u32 struct_size = struct_type->size; 1936 u32 nr_copy_bits; 1937 1938 /* a regular int type is required for the kflag int member */ 1939 if (!btf_type_int_is_regular(member_type)) { 1940 btf_verifier_log_member(env, struct_type, member, 1941 "Invalid member base type"); 1942 return -EINVAL; 1943 } 1944 1945 /* check sanity of bitfield size */ 1946 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset); 1947 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset); 1948 nr_int_data_bits = BTF_INT_BITS(int_data); 1949 if (!nr_bits) { 1950 /* Not a bitfield member, member offset must be at byte 1951 * boundary. 1952 */ 1953 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 1954 btf_verifier_log_member(env, struct_type, member, 1955 "Invalid member offset"); 1956 return -EINVAL; 1957 } 1958 1959 nr_bits = nr_int_data_bits; 1960 } else if (nr_bits > nr_int_data_bits) { 1961 btf_verifier_log_member(env, struct_type, member, 1962 "Invalid member bitfield_size"); 1963 return -EINVAL; 1964 } 1965 1966 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 1967 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off); 1968 if (nr_copy_bits > BITS_PER_U128) { 1969 btf_verifier_log_member(env, struct_type, member, 1970 "nr_copy_bits exceeds 128"); 1971 return -EINVAL; 1972 } 1973 1974 if (struct_size < bytes_offset || 1975 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) { 1976 btf_verifier_log_member(env, struct_type, member, 1977 "Member exceeds struct_size"); 1978 return -EINVAL; 1979 } 1980 1981 return 0; 1982 } 1983 1984 static s32 btf_int_check_meta(struct btf_verifier_env *env, 1985 const struct btf_type *t, 1986 u32 meta_left) 1987 { 1988 u32 int_data, nr_bits, meta_needed = sizeof(int_data); 1989 u16 encoding; 1990 1991 if (meta_left < meta_needed) { 1992 btf_verifier_log_basic(env, t, 1993 "meta_left:%u meta_needed:%u", 1994 meta_left, meta_needed); 1995 return -EINVAL; 1996 } 1997 1998 if (btf_type_vlen(t)) { 1999 btf_verifier_log_type(env, t, "vlen != 0"); 2000 return -EINVAL; 2001 } 2002 2003 if (btf_type_kflag(t)) { 2004 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 2005 return -EINVAL; 2006 } 2007 2008 int_data = btf_type_int(t); 2009 if (int_data & ~BTF_INT_MASK) { 2010 btf_verifier_log_basic(env, t, "Invalid int_data:%x", 2011 int_data); 2012 return -EINVAL; 2013 } 2014 2015 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data); 2016 2017 if (nr_bits > BITS_PER_U128) { 2018 btf_verifier_log_type(env, t, "nr_bits exceeds %zu", 2019 BITS_PER_U128); 2020 return -EINVAL; 2021 } 2022 2023 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) { 2024 btf_verifier_log_type(env, t, "nr_bits exceeds type_size"); 2025 return -EINVAL; 2026 } 2027 2028 /* 2029 * Only one of the encoding bits is allowed and it 2030 * should be sufficient for the pretty print purpose (i.e. decoding). 2031 * Multiple bits can be allowed later if it is found 2032 * to be insufficient. 2033 */ 2034 encoding = BTF_INT_ENCODING(int_data); 2035 if (encoding && 2036 encoding != BTF_INT_SIGNED && 2037 encoding != BTF_INT_CHAR && 2038 encoding != BTF_INT_BOOL) { 2039 btf_verifier_log_type(env, t, "Unsupported encoding"); 2040 return -ENOTSUPP; 2041 } 2042 2043 btf_verifier_log_type(env, t, NULL); 2044 2045 return meta_needed; 2046 } 2047 2048 static void btf_int_log(struct btf_verifier_env *env, 2049 const struct btf_type *t) 2050 { 2051 int int_data = btf_type_int(t); 2052 2053 btf_verifier_log(env, 2054 "size=%u bits_offset=%u nr_bits=%u encoding=%s", 2055 t->size, BTF_INT_OFFSET(int_data), 2056 BTF_INT_BITS(int_data), 2057 btf_int_encoding_str(BTF_INT_ENCODING(int_data))); 2058 } 2059 2060 static void btf_int128_print(struct btf_show *show, void *data) 2061 { 2062 /* data points to a __int128 number. 2063 * Suppose 2064 * int128_num = *(__int128 *)data; 2065 * The below formulas shows what upper_num and lower_num represents: 2066 * upper_num = int128_num >> 64; 2067 * lower_num = int128_num & 0xffffffffFFFFFFFFULL; 2068 */ 2069 u64 upper_num, lower_num; 2070 2071 #ifdef __BIG_ENDIAN_BITFIELD 2072 upper_num = *(u64 *)data; 2073 lower_num = *(u64 *)(data + 8); 2074 #else 2075 upper_num = *(u64 *)(data + 8); 2076 lower_num = *(u64 *)data; 2077 #endif 2078 if (upper_num == 0) 2079 btf_show_type_value(show, "0x%llx", lower_num); 2080 else 2081 btf_show_type_values(show, "0x%llx%016llx", upper_num, 2082 lower_num); 2083 } 2084 2085 static void btf_int128_shift(u64 *print_num, u16 left_shift_bits, 2086 u16 right_shift_bits) 2087 { 2088 u64 upper_num, lower_num; 2089 2090 #ifdef __BIG_ENDIAN_BITFIELD 2091 upper_num = print_num[0]; 2092 lower_num = print_num[1]; 2093 #else 2094 upper_num = print_num[1]; 2095 lower_num = print_num[0]; 2096 #endif 2097 2098 /* shake out un-needed bits by shift/or operations */ 2099 if (left_shift_bits >= 64) { 2100 upper_num = lower_num << (left_shift_bits - 64); 2101 lower_num = 0; 2102 } else { 2103 upper_num = (upper_num << left_shift_bits) | 2104 (lower_num >> (64 - left_shift_bits)); 2105 lower_num = lower_num << left_shift_bits; 2106 } 2107 2108 if (right_shift_bits >= 64) { 2109 lower_num = upper_num >> (right_shift_bits - 64); 2110 upper_num = 0; 2111 } else { 2112 lower_num = (lower_num >> right_shift_bits) | 2113 (upper_num << (64 - right_shift_bits)); 2114 upper_num = upper_num >> right_shift_bits; 2115 } 2116 2117 #ifdef __BIG_ENDIAN_BITFIELD 2118 print_num[0] = upper_num; 2119 print_num[1] = lower_num; 2120 #else 2121 print_num[0] = lower_num; 2122 print_num[1] = upper_num; 2123 #endif 2124 } 2125 2126 static void btf_bitfield_show(void *data, u8 bits_offset, 2127 u8 nr_bits, struct btf_show *show) 2128 { 2129 u16 left_shift_bits, right_shift_bits; 2130 u8 nr_copy_bytes; 2131 u8 nr_copy_bits; 2132 u64 print_num[2] = {}; 2133 2134 nr_copy_bits = nr_bits + bits_offset; 2135 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits); 2136 2137 memcpy(print_num, data, nr_copy_bytes); 2138 2139 #ifdef __BIG_ENDIAN_BITFIELD 2140 left_shift_bits = bits_offset; 2141 #else 2142 left_shift_bits = BITS_PER_U128 - nr_copy_bits; 2143 #endif 2144 right_shift_bits = BITS_PER_U128 - nr_bits; 2145 2146 btf_int128_shift(print_num, left_shift_bits, right_shift_bits); 2147 btf_int128_print(show, print_num); 2148 } 2149 2150 2151 static void btf_int_bits_show(const struct btf *btf, 2152 const struct btf_type *t, 2153 void *data, u8 bits_offset, 2154 struct btf_show *show) 2155 { 2156 u32 int_data = btf_type_int(t); 2157 u8 nr_bits = BTF_INT_BITS(int_data); 2158 u8 total_bits_offset; 2159 2160 /* 2161 * bits_offset is at most 7. 2162 * BTF_INT_OFFSET() cannot exceed 128 bits. 2163 */ 2164 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data); 2165 data += BITS_ROUNDDOWN_BYTES(total_bits_offset); 2166 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset); 2167 btf_bitfield_show(data, bits_offset, nr_bits, show); 2168 } 2169 2170 static void btf_int_show(const struct btf *btf, const struct btf_type *t, 2171 u32 type_id, void *data, u8 bits_offset, 2172 struct btf_show *show) 2173 { 2174 u32 int_data = btf_type_int(t); 2175 u8 encoding = BTF_INT_ENCODING(int_data); 2176 bool sign = encoding & BTF_INT_SIGNED; 2177 u8 nr_bits = BTF_INT_BITS(int_data); 2178 void *safe_data; 2179 2180 safe_data = btf_show_start_type(show, t, type_id, data); 2181 if (!safe_data) 2182 return; 2183 2184 if (bits_offset || BTF_INT_OFFSET(int_data) || 2185 BITS_PER_BYTE_MASKED(nr_bits)) { 2186 btf_int_bits_show(btf, t, safe_data, bits_offset, show); 2187 goto out; 2188 } 2189 2190 switch (nr_bits) { 2191 case 128: 2192 btf_int128_print(show, safe_data); 2193 break; 2194 case 64: 2195 if (sign) 2196 btf_show_type_value(show, "%lld", *(s64 *)safe_data); 2197 else 2198 btf_show_type_value(show, "%llu", *(u64 *)safe_data); 2199 break; 2200 case 32: 2201 if (sign) 2202 btf_show_type_value(show, "%d", *(s32 *)safe_data); 2203 else 2204 btf_show_type_value(show, "%u", *(u32 *)safe_data); 2205 break; 2206 case 16: 2207 if (sign) 2208 btf_show_type_value(show, "%d", *(s16 *)safe_data); 2209 else 2210 btf_show_type_value(show, "%u", *(u16 *)safe_data); 2211 break; 2212 case 8: 2213 if (show->state.array_encoding == BTF_INT_CHAR) { 2214 /* check for null terminator */ 2215 if (show->state.array_terminated) 2216 break; 2217 if (*(char *)data == '\0') { 2218 show->state.array_terminated = 1; 2219 break; 2220 } 2221 if (isprint(*(char *)data)) { 2222 btf_show_type_value(show, "'%c'", 2223 *(char *)safe_data); 2224 break; 2225 } 2226 } 2227 if (sign) 2228 btf_show_type_value(show, "%d", *(s8 *)safe_data); 2229 else 2230 btf_show_type_value(show, "%u", *(u8 *)safe_data); 2231 break; 2232 default: 2233 btf_int_bits_show(btf, t, safe_data, bits_offset, show); 2234 break; 2235 } 2236 out: 2237 btf_show_end_type(show); 2238 } 2239 2240 static const struct btf_kind_operations int_ops = { 2241 .check_meta = btf_int_check_meta, 2242 .resolve = btf_df_resolve, 2243 .check_member = btf_int_check_member, 2244 .check_kflag_member = btf_int_check_kflag_member, 2245 .log_details = btf_int_log, 2246 .show = btf_int_show, 2247 }; 2248 2249 static int btf_modifier_check_member(struct btf_verifier_env *env, 2250 const struct btf_type *struct_type, 2251 const struct btf_member *member, 2252 const struct btf_type *member_type) 2253 { 2254 const struct btf_type *resolved_type; 2255 u32 resolved_type_id = member->type; 2256 struct btf_member resolved_member; 2257 struct btf *btf = env->btf; 2258 2259 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL); 2260 if (!resolved_type) { 2261 btf_verifier_log_member(env, struct_type, member, 2262 "Invalid member"); 2263 return -EINVAL; 2264 } 2265 2266 resolved_member = *member; 2267 resolved_member.type = resolved_type_id; 2268 2269 return btf_type_ops(resolved_type)->check_member(env, struct_type, 2270 &resolved_member, 2271 resolved_type); 2272 } 2273 2274 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env, 2275 const struct btf_type *struct_type, 2276 const struct btf_member *member, 2277 const struct btf_type *member_type) 2278 { 2279 const struct btf_type *resolved_type; 2280 u32 resolved_type_id = member->type; 2281 struct btf_member resolved_member; 2282 struct btf *btf = env->btf; 2283 2284 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL); 2285 if (!resolved_type) { 2286 btf_verifier_log_member(env, struct_type, member, 2287 "Invalid member"); 2288 return -EINVAL; 2289 } 2290 2291 resolved_member = *member; 2292 resolved_member.type = resolved_type_id; 2293 2294 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type, 2295 &resolved_member, 2296 resolved_type); 2297 } 2298 2299 static int btf_ptr_check_member(struct btf_verifier_env *env, 2300 const struct btf_type *struct_type, 2301 const struct btf_member *member, 2302 const struct btf_type *member_type) 2303 { 2304 u32 struct_size, struct_bits_off, bytes_offset; 2305 2306 struct_size = struct_type->size; 2307 struct_bits_off = member->offset; 2308 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 2309 2310 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 2311 btf_verifier_log_member(env, struct_type, member, 2312 "Member is not byte aligned"); 2313 return -EINVAL; 2314 } 2315 2316 if (struct_size - bytes_offset < sizeof(void *)) { 2317 btf_verifier_log_member(env, struct_type, member, 2318 "Member exceeds struct_size"); 2319 return -EINVAL; 2320 } 2321 2322 return 0; 2323 } 2324 2325 static int btf_ref_type_check_meta(struct btf_verifier_env *env, 2326 const struct btf_type *t, 2327 u32 meta_left) 2328 { 2329 if (btf_type_vlen(t)) { 2330 btf_verifier_log_type(env, t, "vlen != 0"); 2331 return -EINVAL; 2332 } 2333 2334 if (btf_type_kflag(t)) { 2335 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 2336 return -EINVAL; 2337 } 2338 2339 if (!BTF_TYPE_ID_VALID(t->type)) { 2340 btf_verifier_log_type(env, t, "Invalid type_id"); 2341 return -EINVAL; 2342 } 2343 2344 /* typedef type must have a valid name, and other ref types, 2345 * volatile, const, restrict, should have a null name. 2346 */ 2347 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) { 2348 if (!t->name_off || 2349 !btf_name_valid_identifier(env->btf, t->name_off)) { 2350 btf_verifier_log_type(env, t, "Invalid name"); 2351 return -EINVAL; 2352 } 2353 } else { 2354 if (t->name_off) { 2355 btf_verifier_log_type(env, t, "Invalid name"); 2356 return -EINVAL; 2357 } 2358 } 2359 2360 btf_verifier_log_type(env, t, NULL); 2361 2362 return 0; 2363 } 2364 2365 static int btf_modifier_resolve(struct btf_verifier_env *env, 2366 const struct resolve_vertex *v) 2367 { 2368 const struct btf_type *t = v->t; 2369 const struct btf_type *next_type; 2370 u32 next_type_id = t->type; 2371 struct btf *btf = env->btf; 2372 2373 next_type = btf_type_by_id(btf, next_type_id); 2374 if (!next_type || btf_type_is_resolve_source_only(next_type)) { 2375 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2376 return -EINVAL; 2377 } 2378 2379 if (!env_type_is_resolve_sink(env, next_type) && 2380 !env_type_is_resolved(env, next_type_id)) 2381 return env_stack_push(env, next_type, next_type_id); 2382 2383 /* Figure out the resolved next_type_id with size. 2384 * They will be stored in the current modifier's 2385 * resolved_ids and resolved_sizes such that it can 2386 * save us a few type-following when we use it later (e.g. in 2387 * pretty print). 2388 */ 2389 if (!btf_type_id_size(btf, &next_type_id, NULL)) { 2390 if (env_type_is_resolved(env, next_type_id)) 2391 next_type = btf_type_id_resolve(btf, &next_type_id); 2392 2393 /* "typedef void new_void", "const void"...etc */ 2394 if (!btf_type_is_void(next_type) && 2395 !btf_type_is_fwd(next_type) && 2396 !btf_type_is_func_proto(next_type)) { 2397 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2398 return -EINVAL; 2399 } 2400 } 2401 2402 env_stack_pop_resolved(env, next_type_id, 0); 2403 2404 return 0; 2405 } 2406 2407 static int btf_var_resolve(struct btf_verifier_env *env, 2408 const struct resolve_vertex *v) 2409 { 2410 const struct btf_type *next_type; 2411 const struct btf_type *t = v->t; 2412 u32 next_type_id = t->type; 2413 struct btf *btf = env->btf; 2414 2415 next_type = btf_type_by_id(btf, next_type_id); 2416 if (!next_type || btf_type_is_resolve_source_only(next_type)) { 2417 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2418 return -EINVAL; 2419 } 2420 2421 if (!env_type_is_resolve_sink(env, next_type) && 2422 !env_type_is_resolved(env, next_type_id)) 2423 return env_stack_push(env, next_type, next_type_id); 2424 2425 if (btf_type_is_modifier(next_type)) { 2426 const struct btf_type *resolved_type; 2427 u32 resolved_type_id; 2428 2429 resolved_type_id = next_type_id; 2430 resolved_type = btf_type_id_resolve(btf, &resolved_type_id); 2431 2432 if (btf_type_is_ptr(resolved_type) && 2433 !env_type_is_resolve_sink(env, resolved_type) && 2434 !env_type_is_resolved(env, resolved_type_id)) 2435 return env_stack_push(env, resolved_type, 2436 resolved_type_id); 2437 } 2438 2439 /* We must resolve to something concrete at this point, no 2440 * forward types or similar that would resolve to size of 2441 * zero is allowed. 2442 */ 2443 if (!btf_type_id_size(btf, &next_type_id, NULL)) { 2444 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2445 return -EINVAL; 2446 } 2447 2448 env_stack_pop_resolved(env, next_type_id, 0); 2449 2450 return 0; 2451 } 2452 2453 static int btf_ptr_resolve(struct btf_verifier_env *env, 2454 const struct resolve_vertex *v) 2455 { 2456 const struct btf_type *next_type; 2457 const struct btf_type *t = v->t; 2458 u32 next_type_id = t->type; 2459 struct btf *btf = env->btf; 2460 2461 next_type = btf_type_by_id(btf, next_type_id); 2462 if (!next_type || btf_type_is_resolve_source_only(next_type)) { 2463 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2464 return -EINVAL; 2465 } 2466 2467 if (!env_type_is_resolve_sink(env, next_type) && 2468 !env_type_is_resolved(env, next_type_id)) 2469 return env_stack_push(env, next_type, next_type_id); 2470 2471 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY, 2472 * the modifier may have stopped resolving when it was resolved 2473 * to a ptr (last-resolved-ptr). 2474 * 2475 * We now need to continue from the last-resolved-ptr to 2476 * ensure the last-resolved-ptr will not referring back to 2477 * the currenct ptr (t). 2478 */ 2479 if (btf_type_is_modifier(next_type)) { 2480 const struct btf_type *resolved_type; 2481 u32 resolved_type_id; 2482 2483 resolved_type_id = next_type_id; 2484 resolved_type = btf_type_id_resolve(btf, &resolved_type_id); 2485 2486 if (btf_type_is_ptr(resolved_type) && 2487 !env_type_is_resolve_sink(env, resolved_type) && 2488 !env_type_is_resolved(env, resolved_type_id)) 2489 return env_stack_push(env, resolved_type, 2490 resolved_type_id); 2491 } 2492 2493 if (!btf_type_id_size(btf, &next_type_id, NULL)) { 2494 if (env_type_is_resolved(env, next_type_id)) 2495 next_type = btf_type_id_resolve(btf, &next_type_id); 2496 2497 if (!btf_type_is_void(next_type) && 2498 !btf_type_is_fwd(next_type) && 2499 !btf_type_is_func_proto(next_type)) { 2500 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2501 return -EINVAL; 2502 } 2503 } 2504 2505 env_stack_pop_resolved(env, next_type_id, 0); 2506 2507 return 0; 2508 } 2509 2510 static void btf_modifier_show(const struct btf *btf, 2511 const struct btf_type *t, 2512 u32 type_id, void *data, 2513 u8 bits_offset, struct btf_show *show) 2514 { 2515 if (btf->resolved_ids) 2516 t = btf_type_id_resolve(btf, &type_id); 2517 else 2518 t = btf_type_skip_modifiers(btf, type_id, NULL); 2519 2520 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show); 2521 } 2522 2523 static void btf_var_show(const struct btf *btf, const struct btf_type *t, 2524 u32 type_id, void *data, u8 bits_offset, 2525 struct btf_show *show) 2526 { 2527 t = btf_type_id_resolve(btf, &type_id); 2528 2529 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show); 2530 } 2531 2532 static void btf_ptr_show(const struct btf *btf, const struct btf_type *t, 2533 u32 type_id, void *data, u8 bits_offset, 2534 struct btf_show *show) 2535 { 2536 void *safe_data; 2537 2538 safe_data = btf_show_start_type(show, t, type_id, data); 2539 if (!safe_data) 2540 return; 2541 2542 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */ 2543 if (show->flags & BTF_SHOW_PTR_RAW) 2544 btf_show_type_value(show, "0x%px", *(void **)safe_data); 2545 else 2546 btf_show_type_value(show, "0x%p", *(void **)safe_data); 2547 btf_show_end_type(show); 2548 } 2549 2550 static void btf_ref_type_log(struct btf_verifier_env *env, 2551 const struct btf_type *t) 2552 { 2553 btf_verifier_log(env, "type_id=%u", t->type); 2554 } 2555 2556 static struct btf_kind_operations modifier_ops = { 2557 .check_meta = btf_ref_type_check_meta, 2558 .resolve = btf_modifier_resolve, 2559 .check_member = btf_modifier_check_member, 2560 .check_kflag_member = btf_modifier_check_kflag_member, 2561 .log_details = btf_ref_type_log, 2562 .show = btf_modifier_show, 2563 }; 2564 2565 static struct btf_kind_operations ptr_ops = { 2566 .check_meta = btf_ref_type_check_meta, 2567 .resolve = btf_ptr_resolve, 2568 .check_member = btf_ptr_check_member, 2569 .check_kflag_member = btf_generic_check_kflag_member, 2570 .log_details = btf_ref_type_log, 2571 .show = btf_ptr_show, 2572 }; 2573 2574 static s32 btf_fwd_check_meta(struct btf_verifier_env *env, 2575 const struct btf_type *t, 2576 u32 meta_left) 2577 { 2578 if (btf_type_vlen(t)) { 2579 btf_verifier_log_type(env, t, "vlen != 0"); 2580 return -EINVAL; 2581 } 2582 2583 if (t->type) { 2584 btf_verifier_log_type(env, t, "type != 0"); 2585 return -EINVAL; 2586 } 2587 2588 /* fwd type must have a valid name */ 2589 if (!t->name_off || 2590 !btf_name_valid_identifier(env->btf, t->name_off)) { 2591 btf_verifier_log_type(env, t, "Invalid name"); 2592 return -EINVAL; 2593 } 2594 2595 btf_verifier_log_type(env, t, NULL); 2596 2597 return 0; 2598 } 2599 2600 static void btf_fwd_type_log(struct btf_verifier_env *env, 2601 const struct btf_type *t) 2602 { 2603 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct"); 2604 } 2605 2606 static struct btf_kind_operations fwd_ops = { 2607 .check_meta = btf_fwd_check_meta, 2608 .resolve = btf_df_resolve, 2609 .check_member = btf_df_check_member, 2610 .check_kflag_member = btf_df_check_kflag_member, 2611 .log_details = btf_fwd_type_log, 2612 .show = btf_df_show, 2613 }; 2614 2615 static int btf_array_check_member(struct btf_verifier_env *env, 2616 const struct btf_type *struct_type, 2617 const struct btf_member *member, 2618 const struct btf_type *member_type) 2619 { 2620 u32 struct_bits_off = member->offset; 2621 u32 struct_size, bytes_offset; 2622 u32 array_type_id, array_size; 2623 struct btf *btf = env->btf; 2624 2625 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 2626 btf_verifier_log_member(env, struct_type, member, 2627 "Member is not byte aligned"); 2628 return -EINVAL; 2629 } 2630 2631 array_type_id = member->type; 2632 btf_type_id_size(btf, &array_type_id, &array_size); 2633 struct_size = struct_type->size; 2634 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 2635 if (struct_size - bytes_offset < array_size) { 2636 btf_verifier_log_member(env, struct_type, member, 2637 "Member exceeds struct_size"); 2638 return -EINVAL; 2639 } 2640 2641 return 0; 2642 } 2643 2644 static s32 btf_array_check_meta(struct btf_verifier_env *env, 2645 const struct btf_type *t, 2646 u32 meta_left) 2647 { 2648 const struct btf_array *array = btf_type_array(t); 2649 u32 meta_needed = sizeof(*array); 2650 2651 if (meta_left < meta_needed) { 2652 btf_verifier_log_basic(env, t, 2653 "meta_left:%u meta_needed:%u", 2654 meta_left, meta_needed); 2655 return -EINVAL; 2656 } 2657 2658 /* array type should not have a name */ 2659 if (t->name_off) { 2660 btf_verifier_log_type(env, t, "Invalid name"); 2661 return -EINVAL; 2662 } 2663 2664 if (btf_type_vlen(t)) { 2665 btf_verifier_log_type(env, t, "vlen != 0"); 2666 return -EINVAL; 2667 } 2668 2669 if (btf_type_kflag(t)) { 2670 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 2671 return -EINVAL; 2672 } 2673 2674 if (t->size) { 2675 btf_verifier_log_type(env, t, "size != 0"); 2676 return -EINVAL; 2677 } 2678 2679 /* Array elem type and index type cannot be in type void, 2680 * so !array->type and !array->index_type are not allowed. 2681 */ 2682 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) { 2683 btf_verifier_log_type(env, t, "Invalid elem"); 2684 return -EINVAL; 2685 } 2686 2687 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) { 2688 btf_verifier_log_type(env, t, "Invalid index"); 2689 return -EINVAL; 2690 } 2691 2692 btf_verifier_log_type(env, t, NULL); 2693 2694 return meta_needed; 2695 } 2696 2697 static int btf_array_resolve(struct btf_verifier_env *env, 2698 const struct resolve_vertex *v) 2699 { 2700 const struct btf_array *array = btf_type_array(v->t); 2701 const struct btf_type *elem_type, *index_type; 2702 u32 elem_type_id, index_type_id; 2703 struct btf *btf = env->btf; 2704 u32 elem_size; 2705 2706 /* Check array->index_type */ 2707 index_type_id = array->index_type; 2708 index_type = btf_type_by_id(btf, index_type_id); 2709 if (btf_type_nosize_or_null(index_type) || 2710 btf_type_is_resolve_source_only(index_type)) { 2711 btf_verifier_log_type(env, v->t, "Invalid index"); 2712 return -EINVAL; 2713 } 2714 2715 if (!env_type_is_resolve_sink(env, index_type) && 2716 !env_type_is_resolved(env, index_type_id)) 2717 return env_stack_push(env, index_type, index_type_id); 2718 2719 index_type = btf_type_id_size(btf, &index_type_id, NULL); 2720 if (!index_type || !btf_type_is_int(index_type) || 2721 !btf_type_int_is_regular(index_type)) { 2722 btf_verifier_log_type(env, v->t, "Invalid index"); 2723 return -EINVAL; 2724 } 2725 2726 /* Check array->type */ 2727 elem_type_id = array->type; 2728 elem_type = btf_type_by_id(btf, elem_type_id); 2729 if (btf_type_nosize_or_null(elem_type) || 2730 btf_type_is_resolve_source_only(elem_type)) { 2731 btf_verifier_log_type(env, v->t, 2732 "Invalid elem"); 2733 return -EINVAL; 2734 } 2735 2736 if (!env_type_is_resolve_sink(env, elem_type) && 2737 !env_type_is_resolved(env, elem_type_id)) 2738 return env_stack_push(env, elem_type, elem_type_id); 2739 2740 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); 2741 if (!elem_type) { 2742 btf_verifier_log_type(env, v->t, "Invalid elem"); 2743 return -EINVAL; 2744 } 2745 2746 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) { 2747 btf_verifier_log_type(env, v->t, "Invalid array of int"); 2748 return -EINVAL; 2749 } 2750 2751 if (array->nelems && elem_size > U32_MAX / array->nelems) { 2752 btf_verifier_log_type(env, v->t, 2753 "Array size overflows U32_MAX"); 2754 return -EINVAL; 2755 } 2756 2757 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems); 2758 2759 return 0; 2760 } 2761 2762 static void btf_array_log(struct btf_verifier_env *env, 2763 const struct btf_type *t) 2764 { 2765 const struct btf_array *array = btf_type_array(t); 2766 2767 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u", 2768 array->type, array->index_type, array->nelems); 2769 } 2770 2771 static void __btf_array_show(const struct btf *btf, const struct btf_type *t, 2772 u32 type_id, void *data, u8 bits_offset, 2773 struct btf_show *show) 2774 { 2775 const struct btf_array *array = btf_type_array(t); 2776 const struct btf_kind_operations *elem_ops; 2777 const struct btf_type *elem_type; 2778 u32 i, elem_size = 0, elem_type_id; 2779 u16 encoding = 0; 2780 2781 elem_type_id = array->type; 2782 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL); 2783 if (elem_type && btf_type_has_size(elem_type)) 2784 elem_size = elem_type->size; 2785 2786 if (elem_type && btf_type_is_int(elem_type)) { 2787 u32 int_type = btf_type_int(elem_type); 2788 2789 encoding = BTF_INT_ENCODING(int_type); 2790 2791 /* 2792 * BTF_INT_CHAR encoding never seems to be set for 2793 * char arrays, so if size is 1 and element is 2794 * printable as a char, we'll do that. 2795 */ 2796 if (elem_size == 1) 2797 encoding = BTF_INT_CHAR; 2798 } 2799 2800 if (!btf_show_start_array_type(show, t, type_id, encoding, data)) 2801 return; 2802 2803 if (!elem_type) 2804 goto out; 2805 elem_ops = btf_type_ops(elem_type); 2806 2807 for (i = 0; i < array->nelems; i++) { 2808 2809 btf_show_start_array_member(show); 2810 2811 elem_ops->show(btf, elem_type, elem_type_id, data, 2812 bits_offset, show); 2813 data += elem_size; 2814 2815 btf_show_end_array_member(show); 2816 2817 if (show->state.array_terminated) 2818 break; 2819 } 2820 out: 2821 btf_show_end_array_type(show); 2822 } 2823 2824 static void btf_array_show(const struct btf *btf, const struct btf_type *t, 2825 u32 type_id, void *data, u8 bits_offset, 2826 struct btf_show *show) 2827 { 2828 const struct btf_member *m = show->state.member; 2829 2830 /* 2831 * First check if any members would be shown (are non-zero). 2832 * See comments above "struct btf_show" definition for more 2833 * details on how this works at a high-level. 2834 */ 2835 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) { 2836 if (!show->state.depth_check) { 2837 show->state.depth_check = show->state.depth + 1; 2838 show->state.depth_to_show = 0; 2839 } 2840 __btf_array_show(btf, t, type_id, data, bits_offset, show); 2841 show->state.member = m; 2842 2843 if (show->state.depth_check != show->state.depth + 1) 2844 return; 2845 show->state.depth_check = 0; 2846 2847 if (show->state.depth_to_show <= show->state.depth) 2848 return; 2849 /* 2850 * Reaching here indicates we have recursed and found 2851 * non-zero array member(s). 2852 */ 2853 } 2854 __btf_array_show(btf, t, type_id, data, bits_offset, show); 2855 } 2856 2857 static struct btf_kind_operations array_ops = { 2858 .check_meta = btf_array_check_meta, 2859 .resolve = btf_array_resolve, 2860 .check_member = btf_array_check_member, 2861 .check_kflag_member = btf_generic_check_kflag_member, 2862 .log_details = btf_array_log, 2863 .show = btf_array_show, 2864 }; 2865 2866 static int btf_struct_check_member(struct btf_verifier_env *env, 2867 const struct btf_type *struct_type, 2868 const struct btf_member *member, 2869 const struct btf_type *member_type) 2870 { 2871 u32 struct_bits_off = member->offset; 2872 u32 struct_size, bytes_offset; 2873 2874 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 2875 btf_verifier_log_member(env, struct_type, member, 2876 "Member is not byte aligned"); 2877 return -EINVAL; 2878 } 2879 2880 struct_size = struct_type->size; 2881 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 2882 if (struct_size - bytes_offset < member_type->size) { 2883 btf_verifier_log_member(env, struct_type, member, 2884 "Member exceeds struct_size"); 2885 return -EINVAL; 2886 } 2887 2888 return 0; 2889 } 2890 2891 static s32 btf_struct_check_meta(struct btf_verifier_env *env, 2892 const struct btf_type *t, 2893 u32 meta_left) 2894 { 2895 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION; 2896 const struct btf_member *member; 2897 u32 meta_needed, last_offset; 2898 struct btf *btf = env->btf; 2899 u32 struct_size = t->size; 2900 u32 offset; 2901 u16 i; 2902 2903 meta_needed = btf_type_vlen(t) * sizeof(*member); 2904 if (meta_left < meta_needed) { 2905 btf_verifier_log_basic(env, t, 2906 "meta_left:%u meta_needed:%u", 2907 meta_left, meta_needed); 2908 return -EINVAL; 2909 } 2910 2911 /* struct type either no name or a valid one */ 2912 if (t->name_off && 2913 !btf_name_valid_identifier(env->btf, t->name_off)) { 2914 btf_verifier_log_type(env, t, "Invalid name"); 2915 return -EINVAL; 2916 } 2917 2918 btf_verifier_log_type(env, t, NULL); 2919 2920 last_offset = 0; 2921 for_each_member(i, t, member) { 2922 if (!btf_name_offset_valid(btf, member->name_off)) { 2923 btf_verifier_log_member(env, t, member, 2924 "Invalid member name_offset:%u", 2925 member->name_off); 2926 return -EINVAL; 2927 } 2928 2929 /* struct member either no name or a valid one */ 2930 if (member->name_off && 2931 !btf_name_valid_identifier(btf, member->name_off)) { 2932 btf_verifier_log_member(env, t, member, "Invalid name"); 2933 return -EINVAL; 2934 } 2935 /* A member cannot be in type void */ 2936 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) { 2937 btf_verifier_log_member(env, t, member, 2938 "Invalid type_id"); 2939 return -EINVAL; 2940 } 2941 2942 offset = btf_member_bit_offset(t, member); 2943 if (is_union && offset) { 2944 btf_verifier_log_member(env, t, member, 2945 "Invalid member bits_offset"); 2946 return -EINVAL; 2947 } 2948 2949 /* 2950 * ">" instead of ">=" because the last member could be 2951 * "char a[0];" 2952 */ 2953 if (last_offset > offset) { 2954 btf_verifier_log_member(env, t, member, 2955 "Invalid member bits_offset"); 2956 return -EINVAL; 2957 } 2958 2959 if (BITS_ROUNDUP_BYTES(offset) > struct_size) { 2960 btf_verifier_log_member(env, t, member, 2961 "Member bits_offset exceeds its struct size"); 2962 return -EINVAL; 2963 } 2964 2965 btf_verifier_log_member(env, t, member, NULL); 2966 last_offset = offset; 2967 } 2968 2969 return meta_needed; 2970 } 2971 2972 static int btf_struct_resolve(struct btf_verifier_env *env, 2973 const struct resolve_vertex *v) 2974 { 2975 const struct btf_member *member; 2976 int err; 2977 u16 i; 2978 2979 /* Before continue resolving the next_member, 2980 * ensure the last member is indeed resolved to a 2981 * type with size info. 2982 */ 2983 if (v->next_member) { 2984 const struct btf_type *last_member_type; 2985 const struct btf_member *last_member; 2986 u16 last_member_type_id; 2987 2988 last_member = btf_type_member(v->t) + v->next_member - 1; 2989 last_member_type_id = last_member->type; 2990 if (WARN_ON_ONCE(!env_type_is_resolved(env, 2991 last_member_type_id))) 2992 return -EINVAL; 2993 2994 last_member_type = btf_type_by_id(env->btf, 2995 last_member_type_id); 2996 if (btf_type_kflag(v->t)) 2997 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t, 2998 last_member, 2999 last_member_type); 3000 else 3001 err = btf_type_ops(last_member_type)->check_member(env, v->t, 3002 last_member, 3003 last_member_type); 3004 if (err) 3005 return err; 3006 } 3007 3008 for_each_member_from(i, v->next_member, v->t, member) { 3009 u32 member_type_id = member->type; 3010 const struct btf_type *member_type = btf_type_by_id(env->btf, 3011 member_type_id); 3012 3013 if (btf_type_nosize_or_null(member_type) || 3014 btf_type_is_resolve_source_only(member_type)) { 3015 btf_verifier_log_member(env, v->t, member, 3016 "Invalid member"); 3017 return -EINVAL; 3018 } 3019 3020 if (!env_type_is_resolve_sink(env, member_type) && 3021 !env_type_is_resolved(env, member_type_id)) { 3022 env_stack_set_next_member(env, i + 1); 3023 return env_stack_push(env, member_type, member_type_id); 3024 } 3025 3026 if (btf_type_kflag(v->t)) 3027 err = btf_type_ops(member_type)->check_kflag_member(env, v->t, 3028 member, 3029 member_type); 3030 else 3031 err = btf_type_ops(member_type)->check_member(env, v->t, 3032 member, 3033 member_type); 3034 if (err) 3035 return err; 3036 } 3037 3038 env_stack_pop_resolved(env, 0, 0); 3039 3040 return 0; 3041 } 3042 3043 static void btf_struct_log(struct btf_verifier_env *env, 3044 const struct btf_type *t) 3045 { 3046 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); 3047 } 3048 3049 static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t, 3050 const char *name, int sz, int align) 3051 { 3052 const struct btf_member *member; 3053 u32 i, off = -ENOENT; 3054 3055 for_each_member(i, t, member) { 3056 const struct btf_type *member_type = btf_type_by_id(btf, 3057 member->type); 3058 if (!__btf_type_is_struct(member_type)) 3059 continue; 3060 if (member_type->size != sz) 3061 continue; 3062 if (strcmp(__btf_name_by_offset(btf, member_type->name_off), name)) 3063 continue; 3064 if (off != -ENOENT) 3065 /* only one such field is allowed */ 3066 return -E2BIG; 3067 off = btf_member_bit_offset(t, member); 3068 if (off % 8) 3069 /* valid C code cannot generate such BTF */ 3070 return -EINVAL; 3071 off /= 8; 3072 if (off % align) 3073 return -EINVAL; 3074 } 3075 return off; 3076 } 3077 3078 static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, 3079 const char *name, int sz, int align) 3080 { 3081 const struct btf_var_secinfo *vsi; 3082 u32 i, off = -ENOENT; 3083 3084 for_each_vsi(i, t, vsi) { 3085 const struct btf_type *var = btf_type_by_id(btf, vsi->type); 3086 const struct btf_type *var_type = btf_type_by_id(btf, var->type); 3087 3088 if (!__btf_type_is_struct(var_type)) 3089 continue; 3090 if (var_type->size != sz) 3091 continue; 3092 if (vsi->size != sz) 3093 continue; 3094 if (strcmp(__btf_name_by_offset(btf, var_type->name_off), name)) 3095 continue; 3096 if (off != -ENOENT) 3097 /* only one such field is allowed */ 3098 return -E2BIG; 3099 off = vsi->offset; 3100 if (off % align) 3101 return -EINVAL; 3102 } 3103 return off; 3104 } 3105 3106 static int btf_find_field(const struct btf *btf, const struct btf_type *t, 3107 const char *name, int sz, int align) 3108 { 3109 3110 if (__btf_type_is_struct(t)) 3111 return btf_find_struct_field(btf, t, name, sz, align); 3112 else if (btf_type_is_datasec(t)) 3113 return btf_find_datasec_var(btf, t, name, sz, align); 3114 return -EINVAL; 3115 } 3116 3117 /* find 'struct bpf_spin_lock' in map value. 3118 * return >= 0 offset if found 3119 * and < 0 in case of error 3120 */ 3121 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t) 3122 { 3123 return btf_find_field(btf, t, "bpf_spin_lock", 3124 sizeof(struct bpf_spin_lock), 3125 __alignof__(struct bpf_spin_lock)); 3126 } 3127 3128 int btf_find_timer(const struct btf *btf, const struct btf_type *t) 3129 { 3130 return btf_find_field(btf, t, "bpf_timer", 3131 sizeof(struct bpf_timer), 3132 __alignof__(struct bpf_timer)); 3133 } 3134 3135 static void __btf_struct_show(const struct btf *btf, const struct btf_type *t, 3136 u32 type_id, void *data, u8 bits_offset, 3137 struct btf_show *show) 3138 { 3139 const struct btf_member *member; 3140 void *safe_data; 3141 u32 i; 3142 3143 safe_data = btf_show_start_struct_type(show, t, type_id, data); 3144 if (!safe_data) 3145 return; 3146 3147 for_each_member(i, t, member) { 3148 const struct btf_type *member_type = btf_type_by_id(btf, 3149 member->type); 3150 const struct btf_kind_operations *ops; 3151 u32 member_offset, bitfield_size; 3152 u32 bytes_offset; 3153 u8 bits8_offset; 3154 3155 btf_show_start_member(show, member); 3156 3157 member_offset = btf_member_bit_offset(t, member); 3158 bitfield_size = btf_member_bitfield_size(t, member); 3159 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset); 3160 bits8_offset = BITS_PER_BYTE_MASKED(member_offset); 3161 if (bitfield_size) { 3162 safe_data = btf_show_start_type(show, member_type, 3163 member->type, 3164 data + bytes_offset); 3165 if (safe_data) 3166 btf_bitfield_show(safe_data, 3167 bits8_offset, 3168 bitfield_size, show); 3169 btf_show_end_type(show); 3170 } else { 3171 ops = btf_type_ops(member_type); 3172 ops->show(btf, member_type, member->type, 3173 data + bytes_offset, bits8_offset, show); 3174 } 3175 3176 btf_show_end_member(show); 3177 } 3178 3179 btf_show_end_struct_type(show); 3180 } 3181 3182 static void btf_struct_show(const struct btf *btf, const struct btf_type *t, 3183 u32 type_id, void *data, u8 bits_offset, 3184 struct btf_show *show) 3185 { 3186 const struct btf_member *m = show->state.member; 3187 3188 /* 3189 * First check if any members would be shown (are non-zero). 3190 * See comments above "struct btf_show" definition for more 3191 * details on how this works at a high-level. 3192 */ 3193 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) { 3194 if (!show->state.depth_check) { 3195 show->state.depth_check = show->state.depth + 1; 3196 show->state.depth_to_show = 0; 3197 } 3198 __btf_struct_show(btf, t, type_id, data, bits_offset, show); 3199 /* Restore saved member data here */ 3200 show->state.member = m; 3201 if (show->state.depth_check != show->state.depth + 1) 3202 return; 3203 show->state.depth_check = 0; 3204 3205 if (show->state.depth_to_show <= show->state.depth) 3206 return; 3207 /* 3208 * Reaching here indicates we have recursed and found 3209 * non-zero child values. 3210 */ 3211 } 3212 3213 __btf_struct_show(btf, t, type_id, data, bits_offset, show); 3214 } 3215 3216 static struct btf_kind_operations struct_ops = { 3217 .check_meta = btf_struct_check_meta, 3218 .resolve = btf_struct_resolve, 3219 .check_member = btf_struct_check_member, 3220 .check_kflag_member = btf_generic_check_kflag_member, 3221 .log_details = btf_struct_log, 3222 .show = btf_struct_show, 3223 }; 3224 3225 static int btf_enum_check_member(struct btf_verifier_env *env, 3226 const struct btf_type *struct_type, 3227 const struct btf_member *member, 3228 const struct btf_type *member_type) 3229 { 3230 u32 struct_bits_off = member->offset; 3231 u32 struct_size, bytes_offset; 3232 3233 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 3234 btf_verifier_log_member(env, struct_type, member, 3235 "Member is not byte aligned"); 3236 return -EINVAL; 3237 } 3238 3239 struct_size = struct_type->size; 3240 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 3241 if (struct_size - bytes_offset < member_type->size) { 3242 btf_verifier_log_member(env, struct_type, member, 3243 "Member exceeds struct_size"); 3244 return -EINVAL; 3245 } 3246 3247 return 0; 3248 } 3249 3250 static int btf_enum_check_kflag_member(struct btf_verifier_env *env, 3251 const struct btf_type *struct_type, 3252 const struct btf_member *member, 3253 const struct btf_type *member_type) 3254 { 3255 u32 struct_bits_off, nr_bits, bytes_end, struct_size; 3256 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE; 3257 3258 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset); 3259 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset); 3260 if (!nr_bits) { 3261 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 3262 btf_verifier_log_member(env, struct_type, member, 3263 "Member is not byte aligned"); 3264 return -EINVAL; 3265 } 3266 3267 nr_bits = int_bitsize; 3268 } else if (nr_bits > int_bitsize) { 3269 btf_verifier_log_member(env, struct_type, member, 3270 "Invalid member bitfield_size"); 3271 return -EINVAL; 3272 } 3273 3274 struct_size = struct_type->size; 3275 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits); 3276 if (struct_size < bytes_end) { 3277 btf_verifier_log_member(env, struct_type, member, 3278 "Member exceeds struct_size"); 3279 return -EINVAL; 3280 } 3281 3282 return 0; 3283 } 3284 3285 static s32 btf_enum_check_meta(struct btf_verifier_env *env, 3286 const struct btf_type *t, 3287 u32 meta_left) 3288 { 3289 const struct btf_enum *enums = btf_type_enum(t); 3290 struct btf *btf = env->btf; 3291 u16 i, nr_enums; 3292 u32 meta_needed; 3293 3294 nr_enums = btf_type_vlen(t); 3295 meta_needed = nr_enums * sizeof(*enums); 3296 3297 if (meta_left < meta_needed) { 3298 btf_verifier_log_basic(env, t, 3299 "meta_left:%u meta_needed:%u", 3300 meta_left, meta_needed); 3301 return -EINVAL; 3302 } 3303 3304 if (btf_type_kflag(t)) { 3305 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3306 return -EINVAL; 3307 } 3308 3309 if (t->size > 8 || !is_power_of_2(t->size)) { 3310 btf_verifier_log_type(env, t, "Unexpected size"); 3311 return -EINVAL; 3312 } 3313 3314 /* enum type either no name or a valid one */ 3315 if (t->name_off && 3316 !btf_name_valid_identifier(env->btf, t->name_off)) { 3317 btf_verifier_log_type(env, t, "Invalid name"); 3318 return -EINVAL; 3319 } 3320 3321 btf_verifier_log_type(env, t, NULL); 3322 3323 for (i = 0; i < nr_enums; i++) { 3324 if (!btf_name_offset_valid(btf, enums[i].name_off)) { 3325 btf_verifier_log(env, "\tInvalid name_offset:%u", 3326 enums[i].name_off); 3327 return -EINVAL; 3328 } 3329 3330 /* enum member must have a valid name */ 3331 if (!enums[i].name_off || 3332 !btf_name_valid_identifier(btf, enums[i].name_off)) { 3333 btf_verifier_log_type(env, t, "Invalid name"); 3334 return -EINVAL; 3335 } 3336 3337 if (env->log.level == BPF_LOG_KERNEL) 3338 continue; 3339 btf_verifier_log(env, "\t%s val=%d\n", 3340 __btf_name_by_offset(btf, enums[i].name_off), 3341 enums[i].val); 3342 } 3343 3344 return meta_needed; 3345 } 3346 3347 static void btf_enum_log(struct btf_verifier_env *env, 3348 const struct btf_type *t) 3349 { 3350 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); 3351 } 3352 3353 static void btf_enum_show(const struct btf *btf, const struct btf_type *t, 3354 u32 type_id, void *data, u8 bits_offset, 3355 struct btf_show *show) 3356 { 3357 const struct btf_enum *enums = btf_type_enum(t); 3358 u32 i, nr_enums = btf_type_vlen(t); 3359 void *safe_data; 3360 int v; 3361 3362 safe_data = btf_show_start_type(show, t, type_id, data); 3363 if (!safe_data) 3364 return; 3365 3366 v = *(int *)safe_data; 3367 3368 for (i = 0; i < nr_enums; i++) { 3369 if (v != enums[i].val) 3370 continue; 3371 3372 btf_show_type_value(show, "%s", 3373 __btf_name_by_offset(btf, 3374 enums[i].name_off)); 3375 3376 btf_show_end_type(show); 3377 return; 3378 } 3379 3380 btf_show_type_value(show, "%d", v); 3381 btf_show_end_type(show); 3382 } 3383 3384 static struct btf_kind_operations enum_ops = { 3385 .check_meta = btf_enum_check_meta, 3386 .resolve = btf_df_resolve, 3387 .check_member = btf_enum_check_member, 3388 .check_kflag_member = btf_enum_check_kflag_member, 3389 .log_details = btf_enum_log, 3390 .show = btf_enum_show, 3391 }; 3392 3393 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env, 3394 const struct btf_type *t, 3395 u32 meta_left) 3396 { 3397 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param); 3398 3399 if (meta_left < meta_needed) { 3400 btf_verifier_log_basic(env, t, 3401 "meta_left:%u meta_needed:%u", 3402 meta_left, meta_needed); 3403 return -EINVAL; 3404 } 3405 3406 if (t->name_off) { 3407 btf_verifier_log_type(env, t, "Invalid name"); 3408 return -EINVAL; 3409 } 3410 3411 if (btf_type_kflag(t)) { 3412 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3413 return -EINVAL; 3414 } 3415 3416 btf_verifier_log_type(env, t, NULL); 3417 3418 return meta_needed; 3419 } 3420 3421 static void btf_func_proto_log(struct btf_verifier_env *env, 3422 const struct btf_type *t) 3423 { 3424 const struct btf_param *args = (const struct btf_param *)(t + 1); 3425 u16 nr_args = btf_type_vlen(t), i; 3426 3427 btf_verifier_log(env, "return=%u args=(", t->type); 3428 if (!nr_args) { 3429 btf_verifier_log(env, "void"); 3430 goto done; 3431 } 3432 3433 if (nr_args == 1 && !args[0].type) { 3434 /* Only one vararg */ 3435 btf_verifier_log(env, "vararg"); 3436 goto done; 3437 } 3438 3439 btf_verifier_log(env, "%u %s", args[0].type, 3440 __btf_name_by_offset(env->btf, 3441 args[0].name_off)); 3442 for (i = 1; i < nr_args - 1; i++) 3443 btf_verifier_log(env, ", %u %s", args[i].type, 3444 __btf_name_by_offset(env->btf, 3445 args[i].name_off)); 3446 3447 if (nr_args > 1) { 3448 const struct btf_param *last_arg = &args[nr_args - 1]; 3449 3450 if (last_arg->type) 3451 btf_verifier_log(env, ", %u %s", last_arg->type, 3452 __btf_name_by_offset(env->btf, 3453 last_arg->name_off)); 3454 else 3455 btf_verifier_log(env, ", vararg"); 3456 } 3457 3458 done: 3459 btf_verifier_log(env, ")"); 3460 } 3461 3462 static struct btf_kind_operations func_proto_ops = { 3463 .check_meta = btf_func_proto_check_meta, 3464 .resolve = btf_df_resolve, 3465 /* 3466 * BTF_KIND_FUNC_PROTO cannot be directly referred by 3467 * a struct's member. 3468 * 3469 * It should be a function pointer instead. 3470 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO) 3471 * 3472 * Hence, there is no btf_func_check_member(). 3473 */ 3474 .check_member = btf_df_check_member, 3475 .check_kflag_member = btf_df_check_kflag_member, 3476 .log_details = btf_func_proto_log, 3477 .show = btf_df_show, 3478 }; 3479 3480 static s32 btf_func_check_meta(struct btf_verifier_env *env, 3481 const struct btf_type *t, 3482 u32 meta_left) 3483 { 3484 if (!t->name_off || 3485 !btf_name_valid_identifier(env->btf, t->name_off)) { 3486 btf_verifier_log_type(env, t, "Invalid name"); 3487 return -EINVAL; 3488 } 3489 3490 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) { 3491 btf_verifier_log_type(env, t, "Invalid func linkage"); 3492 return -EINVAL; 3493 } 3494 3495 if (btf_type_kflag(t)) { 3496 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3497 return -EINVAL; 3498 } 3499 3500 btf_verifier_log_type(env, t, NULL); 3501 3502 return 0; 3503 } 3504 3505 static struct btf_kind_operations func_ops = { 3506 .check_meta = btf_func_check_meta, 3507 .resolve = btf_df_resolve, 3508 .check_member = btf_df_check_member, 3509 .check_kflag_member = btf_df_check_kflag_member, 3510 .log_details = btf_ref_type_log, 3511 .show = btf_df_show, 3512 }; 3513 3514 static s32 btf_var_check_meta(struct btf_verifier_env *env, 3515 const struct btf_type *t, 3516 u32 meta_left) 3517 { 3518 const struct btf_var *var; 3519 u32 meta_needed = sizeof(*var); 3520 3521 if (meta_left < meta_needed) { 3522 btf_verifier_log_basic(env, t, 3523 "meta_left:%u meta_needed:%u", 3524 meta_left, meta_needed); 3525 return -EINVAL; 3526 } 3527 3528 if (btf_type_vlen(t)) { 3529 btf_verifier_log_type(env, t, "vlen != 0"); 3530 return -EINVAL; 3531 } 3532 3533 if (btf_type_kflag(t)) { 3534 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3535 return -EINVAL; 3536 } 3537 3538 if (!t->name_off || 3539 !__btf_name_valid(env->btf, t->name_off, true)) { 3540 btf_verifier_log_type(env, t, "Invalid name"); 3541 return -EINVAL; 3542 } 3543 3544 /* A var cannot be in type void */ 3545 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) { 3546 btf_verifier_log_type(env, t, "Invalid type_id"); 3547 return -EINVAL; 3548 } 3549 3550 var = btf_type_var(t); 3551 if (var->linkage != BTF_VAR_STATIC && 3552 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) { 3553 btf_verifier_log_type(env, t, "Linkage not supported"); 3554 return -EINVAL; 3555 } 3556 3557 btf_verifier_log_type(env, t, NULL); 3558 3559 return meta_needed; 3560 } 3561 3562 static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t) 3563 { 3564 const struct btf_var *var = btf_type_var(t); 3565 3566 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage); 3567 } 3568 3569 static const struct btf_kind_operations var_ops = { 3570 .check_meta = btf_var_check_meta, 3571 .resolve = btf_var_resolve, 3572 .check_member = btf_df_check_member, 3573 .check_kflag_member = btf_df_check_kflag_member, 3574 .log_details = btf_var_log, 3575 .show = btf_var_show, 3576 }; 3577 3578 static s32 btf_datasec_check_meta(struct btf_verifier_env *env, 3579 const struct btf_type *t, 3580 u32 meta_left) 3581 { 3582 const struct btf_var_secinfo *vsi; 3583 u64 last_vsi_end_off = 0, sum = 0; 3584 u32 i, meta_needed; 3585 3586 meta_needed = btf_type_vlen(t) * sizeof(*vsi); 3587 if (meta_left < meta_needed) { 3588 btf_verifier_log_basic(env, t, 3589 "meta_left:%u meta_needed:%u", 3590 meta_left, meta_needed); 3591 return -EINVAL; 3592 } 3593 3594 if (!t->size) { 3595 btf_verifier_log_type(env, t, "size == 0"); 3596 return -EINVAL; 3597 } 3598 3599 if (btf_type_kflag(t)) { 3600 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3601 return -EINVAL; 3602 } 3603 3604 if (!t->name_off || 3605 !btf_name_valid_section(env->btf, t->name_off)) { 3606 btf_verifier_log_type(env, t, "Invalid name"); 3607 return -EINVAL; 3608 } 3609 3610 btf_verifier_log_type(env, t, NULL); 3611 3612 for_each_vsi(i, t, vsi) { 3613 /* A var cannot be in type void */ 3614 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) { 3615 btf_verifier_log_vsi(env, t, vsi, 3616 "Invalid type_id"); 3617 return -EINVAL; 3618 } 3619 3620 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) { 3621 btf_verifier_log_vsi(env, t, vsi, 3622 "Invalid offset"); 3623 return -EINVAL; 3624 } 3625 3626 if (!vsi->size || vsi->size > t->size) { 3627 btf_verifier_log_vsi(env, t, vsi, 3628 "Invalid size"); 3629 return -EINVAL; 3630 } 3631 3632 last_vsi_end_off = vsi->offset + vsi->size; 3633 if (last_vsi_end_off > t->size) { 3634 btf_verifier_log_vsi(env, t, vsi, 3635 "Invalid offset+size"); 3636 return -EINVAL; 3637 } 3638 3639 btf_verifier_log_vsi(env, t, vsi, NULL); 3640 sum += vsi->size; 3641 } 3642 3643 if (t->size < sum) { 3644 btf_verifier_log_type(env, t, "Invalid btf_info size"); 3645 return -EINVAL; 3646 } 3647 3648 return meta_needed; 3649 } 3650 3651 static int btf_datasec_resolve(struct btf_verifier_env *env, 3652 const struct resolve_vertex *v) 3653 { 3654 const struct btf_var_secinfo *vsi; 3655 struct btf *btf = env->btf; 3656 u16 i; 3657 3658 for_each_vsi_from(i, v->next_member, v->t, vsi) { 3659 u32 var_type_id = vsi->type, type_id, type_size = 0; 3660 const struct btf_type *var_type = btf_type_by_id(env->btf, 3661 var_type_id); 3662 if (!var_type || !btf_type_is_var(var_type)) { 3663 btf_verifier_log_vsi(env, v->t, vsi, 3664 "Not a VAR kind member"); 3665 return -EINVAL; 3666 } 3667 3668 if (!env_type_is_resolve_sink(env, var_type) && 3669 !env_type_is_resolved(env, var_type_id)) { 3670 env_stack_set_next_member(env, i + 1); 3671 return env_stack_push(env, var_type, var_type_id); 3672 } 3673 3674 type_id = var_type->type; 3675 if (!btf_type_id_size(btf, &type_id, &type_size)) { 3676 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type"); 3677 return -EINVAL; 3678 } 3679 3680 if (vsi->size < type_size) { 3681 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size"); 3682 return -EINVAL; 3683 } 3684 } 3685 3686 env_stack_pop_resolved(env, 0, 0); 3687 return 0; 3688 } 3689 3690 static void btf_datasec_log(struct btf_verifier_env *env, 3691 const struct btf_type *t) 3692 { 3693 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); 3694 } 3695 3696 static void btf_datasec_show(const struct btf *btf, 3697 const struct btf_type *t, u32 type_id, 3698 void *data, u8 bits_offset, 3699 struct btf_show *show) 3700 { 3701 const struct btf_var_secinfo *vsi; 3702 const struct btf_type *var; 3703 u32 i; 3704 3705 if (!btf_show_start_type(show, t, type_id, data)) 3706 return; 3707 3708 btf_show_type_value(show, "section (\"%s\") = {", 3709 __btf_name_by_offset(btf, t->name_off)); 3710 for_each_vsi(i, t, vsi) { 3711 var = btf_type_by_id(btf, vsi->type); 3712 if (i) 3713 btf_show(show, ","); 3714 btf_type_ops(var)->show(btf, var, vsi->type, 3715 data + vsi->offset, bits_offset, show); 3716 } 3717 btf_show_end_type(show); 3718 } 3719 3720 static const struct btf_kind_operations datasec_ops = { 3721 .check_meta = btf_datasec_check_meta, 3722 .resolve = btf_datasec_resolve, 3723 .check_member = btf_df_check_member, 3724 .check_kflag_member = btf_df_check_kflag_member, 3725 .log_details = btf_datasec_log, 3726 .show = btf_datasec_show, 3727 }; 3728 3729 static s32 btf_float_check_meta(struct btf_verifier_env *env, 3730 const struct btf_type *t, 3731 u32 meta_left) 3732 { 3733 if (btf_type_vlen(t)) { 3734 btf_verifier_log_type(env, t, "vlen != 0"); 3735 return -EINVAL; 3736 } 3737 3738 if (btf_type_kflag(t)) { 3739 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3740 return -EINVAL; 3741 } 3742 3743 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 && 3744 t->size != 16) { 3745 btf_verifier_log_type(env, t, "Invalid type_size"); 3746 return -EINVAL; 3747 } 3748 3749 btf_verifier_log_type(env, t, NULL); 3750 3751 return 0; 3752 } 3753 3754 static int btf_float_check_member(struct btf_verifier_env *env, 3755 const struct btf_type *struct_type, 3756 const struct btf_member *member, 3757 const struct btf_type *member_type) 3758 { 3759 u64 start_offset_bytes; 3760 u64 end_offset_bytes; 3761 u64 misalign_bits; 3762 u64 align_bytes; 3763 u64 align_bits; 3764 3765 /* Different architectures have different alignment requirements, so 3766 * here we check only for the reasonable minimum. This way we ensure 3767 * that types after CO-RE can pass the kernel BTF verifier. 3768 */ 3769 align_bytes = min_t(u64, sizeof(void *), member_type->size); 3770 align_bits = align_bytes * BITS_PER_BYTE; 3771 div64_u64_rem(member->offset, align_bits, &misalign_bits); 3772 if (misalign_bits) { 3773 btf_verifier_log_member(env, struct_type, member, 3774 "Member is not properly aligned"); 3775 return -EINVAL; 3776 } 3777 3778 start_offset_bytes = member->offset / BITS_PER_BYTE; 3779 end_offset_bytes = start_offset_bytes + member_type->size; 3780 if (end_offset_bytes > struct_type->size) { 3781 btf_verifier_log_member(env, struct_type, member, 3782 "Member exceeds struct_size"); 3783 return -EINVAL; 3784 } 3785 3786 return 0; 3787 } 3788 3789 static void btf_float_log(struct btf_verifier_env *env, 3790 const struct btf_type *t) 3791 { 3792 btf_verifier_log(env, "size=%u", t->size); 3793 } 3794 3795 static const struct btf_kind_operations float_ops = { 3796 .check_meta = btf_float_check_meta, 3797 .resolve = btf_df_resolve, 3798 .check_member = btf_float_check_member, 3799 .check_kflag_member = btf_generic_check_kflag_member, 3800 .log_details = btf_float_log, 3801 .show = btf_df_show, 3802 }; 3803 3804 static int btf_func_proto_check(struct btf_verifier_env *env, 3805 const struct btf_type *t) 3806 { 3807 const struct btf_type *ret_type; 3808 const struct btf_param *args; 3809 const struct btf *btf; 3810 u16 nr_args, i; 3811 int err; 3812 3813 btf = env->btf; 3814 args = (const struct btf_param *)(t + 1); 3815 nr_args = btf_type_vlen(t); 3816 3817 /* Check func return type which could be "void" (t->type == 0) */ 3818 if (t->type) { 3819 u32 ret_type_id = t->type; 3820 3821 ret_type = btf_type_by_id(btf, ret_type_id); 3822 if (!ret_type) { 3823 btf_verifier_log_type(env, t, "Invalid return type"); 3824 return -EINVAL; 3825 } 3826 3827 if (btf_type_needs_resolve(ret_type) && 3828 !env_type_is_resolved(env, ret_type_id)) { 3829 err = btf_resolve(env, ret_type, ret_type_id); 3830 if (err) 3831 return err; 3832 } 3833 3834 /* Ensure the return type is a type that has a size */ 3835 if (!btf_type_id_size(btf, &ret_type_id, NULL)) { 3836 btf_verifier_log_type(env, t, "Invalid return type"); 3837 return -EINVAL; 3838 } 3839 } 3840 3841 if (!nr_args) 3842 return 0; 3843 3844 /* Last func arg type_id could be 0 if it is a vararg */ 3845 if (!args[nr_args - 1].type) { 3846 if (args[nr_args - 1].name_off) { 3847 btf_verifier_log_type(env, t, "Invalid arg#%u", 3848 nr_args); 3849 return -EINVAL; 3850 } 3851 nr_args--; 3852 } 3853 3854 err = 0; 3855 for (i = 0; i < nr_args; i++) { 3856 const struct btf_type *arg_type; 3857 u32 arg_type_id; 3858 3859 arg_type_id = args[i].type; 3860 arg_type = btf_type_by_id(btf, arg_type_id); 3861 if (!arg_type) { 3862 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); 3863 err = -EINVAL; 3864 break; 3865 } 3866 3867 if (args[i].name_off && 3868 (!btf_name_offset_valid(btf, args[i].name_off) || 3869 !btf_name_valid_identifier(btf, args[i].name_off))) { 3870 btf_verifier_log_type(env, t, 3871 "Invalid arg#%u", i + 1); 3872 err = -EINVAL; 3873 break; 3874 } 3875 3876 if (btf_type_needs_resolve(arg_type) && 3877 !env_type_is_resolved(env, arg_type_id)) { 3878 err = btf_resolve(env, arg_type, arg_type_id); 3879 if (err) 3880 break; 3881 } 3882 3883 if (!btf_type_id_size(btf, &arg_type_id, NULL)) { 3884 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); 3885 err = -EINVAL; 3886 break; 3887 } 3888 } 3889 3890 return err; 3891 } 3892 3893 static int btf_func_check(struct btf_verifier_env *env, 3894 const struct btf_type *t) 3895 { 3896 const struct btf_type *proto_type; 3897 const struct btf_param *args; 3898 const struct btf *btf; 3899 u16 nr_args, i; 3900 3901 btf = env->btf; 3902 proto_type = btf_type_by_id(btf, t->type); 3903 3904 if (!proto_type || !btf_type_is_func_proto(proto_type)) { 3905 btf_verifier_log_type(env, t, "Invalid type_id"); 3906 return -EINVAL; 3907 } 3908 3909 args = (const struct btf_param *)(proto_type + 1); 3910 nr_args = btf_type_vlen(proto_type); 3911 for (i = 0; i < nr_args; i++) { 3912 if (!args[i].name_off && args[i].type) { 3913 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); 3914 return -EINVAL; 3915 } 3916 } 3917 3918 return 0; 3919 } 3920 3921 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = { 3922 [BTF_KIND_INT] = &int_ops, 3923 [BTF_KIND_PTR] = &ptr_ops, 3924 [BTF_KIND_ARRAY] = &array_ops, 3925 [BTF_KIND_STRUCT] = &struct_ops, 3926 [BTF_KIND_UNION] = &struct_ops, 3927 [BTF_KIND_ENUM] = &enum_ops, 3928 [BTF_KIND_FWD] = &fwd_ops, 3929 [BTF_KIND_TYPEDEF] = &modifier_ops, 3930 [BTF_KIND_VOLATILE] = &modifier_ops, 3931 [BTF_KIND_CONST] = &modifier_ops, 3932 [BTF_KIND_RESTRICT] = &modifier_ops, 3933 [BTF_KIND_FUNC] = &func_ops, 3934 [BTF_KIND_FUNC_PROTO] = &func_proto_ops, 3935 [BTF_KIND_VAR] = &var_ops, 3936 [BTF_KIND_DATASEC] = &datasec_ops, 3937 [BTF_KIND_FLOAT] = &float_ops, 3938 }; 3939 3940 static s32 btf_check_meta(struct btf_verifier_env *env, 3941 const struct btf_type *t, 3942 u32 meta_left) 3943 { 3944 u32 saved_meta_left = meta_left; 3945 s32 var_meta_size; 3946 3947 if (meta_left < sizeof(*t)) { 3948 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu", 3949 env->log_type_id, meta_left, sizeof(*t)); 3950 return -EINVAL; 3951 } 3952 meta_left -= sizeof(*t); 3953 3954 if (t->info & ~BTF_INFO_MASK) { 3955 btf_verifier_log(env, "[%u] Invalid btf_info:%x", 3956 env->log_type_id, t->info); 3957 return -EINVAL; 3958 } 3959 3960 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX || 3961 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) { 3962 btf_verifier_log(env, "[%u] Invalid kind:%u", 3963 env->log_type_id, BTF_INFO_KIND(t->info)); 3964 return -EINVAL; 3965 } 3966 3967 if (!btf_name_offset_valid(env->btf, t->name_off)) { 3968 btf_verifier_log(env, "[%u] Invalid name_offset:%u", 3969 env->log_type_id, t->name_off); 3970 return -EINVAL; 3971 } 3972 3973 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left); 3974 if (var_meta_size < 0) 3975 return var_meta_size; 3976 3977 meta_left -= var_meta_size; 3978 3979 return saved_meta_left - meta_left; 3980 } 3981 3982 static int btf_check_all_metas(struct btf_verifier_env *env) 3983 { 3984 struct btf *btf = env->btf; 3985 struct btf_header *hdr; 3986 void *cur, *end; 3987 3988 hdr = &btf->hdr; 3989 cur = btf->nohdr_data + hdr->type_off; 3990 end = cur + hdr->type_len; 3991 3992 env->log_type_id = btf->base_btf ? btf->start_id : 1; 3993 while (cur < end) { 3994 struct btf_type *t = cur; 3995 s32 meta_size; 3996 3997 meta_size = btf_check_meta(env, t, end - cur); 3998 if (meta_size < 0) 3999 return meta_size; 4000 4001 btf_add_type(env, t); 4002 cur += meta_size; 4003 env->log_type_id++; 4004 } 4005 4006 return 0; 4007 } 4008 4009 static bool btf_resolve_valid(struct btf_verifier_env *env, 4010 const struct btf_type *t, 4011 u32 type_id) 4012 { 4013 struct btf *btf = env->btf; 4014 4015 if (!env_type_is_resolved(env, type_id)) 4016 return false; 4017 4018 if (btf_type_is_struct(t) || btf_type_is_datasec(t)) 4019 return !btf_resolved_type_id(btf, type_id) && 4020 !btf_resolved_type_size(btf, type_id); 4021 4022 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) || 4023 btf_type_is_var(t)) { 4024 t = btf_type_id_resolve(btf, &type_id); 4025 return t && 4026 !btf_type_is_modifier(t) && 4027 !btf_type_is_var(t) && 4028 !btf_type_is_datasec(t); 4029 } 4030 4031 if (btf_type_is_array(t)) { 4032 const struct btf_array *array = btf_type_array(t); 4033 const struct btf_type *elem_type; 4034 u32 elem_type_id = array->type; 4035 u32 elem_size; 4036 4037 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); 4038 return elem_type && !btf_type_is_modifier(elem_type) && 4039 (array->nelems * elem_size == 4040 btf_resolved_type_size(btf, type_id)); 4041 } 4042 4043 return false; 4044 } 4045 4046 static int btf_resolve(struct btf_verifier_env *env, 4047 const struct btf_type *t, u32 type_id) 4048 { 4049 u32 save_log_type_id = env->log_type_id; 4050 const struct resolve_vertex *v; 4051 int err = 0; 4052 4053 env->resolve_mode = RESOLVE_TBD; 4054 env_stack_push(env, t, type_id); 4055 while (!err && (v = env_stack_peak(env))) { 4056 env->log_type_id = v->type_id; 4057 err = btf_type_ops(v->t)->resolve(env, v); 4058 } 4059 4060 env->log_type_id = type_id; 4061 if (err == -E2BIG) { 4062 btf_verifier_log_type(env, t, 4063 "Exceeded max resolving depth:%u", 4064 MAX_RESOLVE_DEPTH); 4065 } else if (err == -EEXIST) { 4066 btf_verifier_log_type(env, t, "Loop detected"); 4067 } 4068 4069 /* Final sanity check */ 4070 if (!err && !btf_resolve_valid(env, t, type_id)) { 4071 btf_verifier_log_type(env, t, "Invalid resolve state"); 4072 err = -EINVAL; 4073 } 4074 4075 env->log_type_id = save_log_type_id; 4076 return err; 4077 } 4078 4079 static int btf_check_all_types(struct btf_verifier_env *env) 4080 { 4081 struct btf *btf = env->btf; 4082 const struct btf_type *t; 4083 u32 type_id, i; 4084 int err; 4085 4086 err = env_resolve_init(env); 4087 if (err) 4088 return err; 4089 4090 env->phase++; 4091 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) { 4092 type_id = btf->start_id + i; 4093 t = btf_type_by_id(btf, type_id); 4094 4095 env->log_type_id = type_id; 4096 if (btf_type_needs_resolve(t) && 4097 !env_type_is_resolved(env, type_id)) { 4098 err = btf_resolve(env, t, type_id); 4099 if (err) 4100 return err; 4101 } 4102 4103 if (btf_type_is_func_proto(t)) { 4104 err = btf_func_proto_check(env, t); 4105 if (err) 4106 return err; 4107 } 4108 4109 if (btf_type_is_func(t)) { 4110 err = btf_func_check(env, t); 4111 if (err) 4112 return err; 4113 } 4114 } 4115 4116 return 0; 4117 } 4118 4119 static int btf_parse_type_sec(struct btf_verifier_env *env) 4120 { 4121 const struct btf_header *hdr = &env->btf->hdr; 4122 int err; 4123 4124 /* Type section must align to 4 bytes */ 4125 if (hdr->type_off & (sizeof(u32) - 1)) { 4126 btf_verifier_log(env, "Unaligned type_off"); 4127 return -EINVAL; 4128 } 4129 4130 if (!env->btf->base_btf && !hdr->type_len) { 4131 btf_verifier_log(env, "No type found"); 4132 return -EINVAL; 4133 } 4134 4135 err = btf_check_all_metas(env); 4136 if (err) 4137 return err; 4138 4139 return btf_check_all_types(env); 4140 } 4141 4142 static int btf_parse_str_sec(struct btf_verifier_env *env) 4143 { 4144 const struct btf_header *hdr; 4145 struct btf *btf = env->btf; 4146 const char *start, *end; 4147 4148 hdr = &btf->hdr; 4149 start = btf->nohdr_data + hdr->str_off; 4150 end = start + hdr->str_len; 4151 4152 if (end != btf->data + btf->data_size) { 4153 btf_verifier_log(env, "String section is not at the end"); 4154 return -EINVAL; 4155 } 4156 4157 btf->strings = start; 4158 4159 if (btf->base_btf && !hdr->str_len) 4160 return 0; 4161 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) { 4162 btf_verifier_log(env, "Invalid string section"); 4163 return -EINVAL; 4164 } 4165 if (!btf->base_btf && start[0]) { 4166 btf_verifier_log(env, "Invalid string section"); 4167 return -EINVAL; 4168 } 4169 4170 return 0; 4171 } 4172 4173 static const size_t btf_sec_info_offset[] = { 4174 offsetof(struct btf_header, type_off), 4175 offsetof(struct btf_header, str_off), 4176 }; 4177 4178 static int btf_sec_info_cmp(const void *a, const void *b) 4179 { 4180 const struct btf_sec_info *x = a; 4181 const struct btf_sec_info *y = b; 4182 4183 return (int)(x->off - y->off) ? : (int)(x->len - y->len); 4184 } 4185 4186 static int btf_check_sec_info(struct btf_verifier_env *env, 4187 u32 btf_data_size) 4188 { 4189 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)]; 4190 u32 total, expected_total, i; 4191 const struct btf_header *hdr; 4192 const struct btf *btf; 4193 4194 btf = env->btf; 4195 hdr = &btf->hdr; 4196 4197 /* Populate the secs from hdr */ 4198 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) 4199 secs[i] = *(struct btf_sec_info *)((void *)hdr + 4200 btf_sec_info_offset[i]); 4201 4202 sort(secs, ARRAY_SIZE(btf_sec_info_offset), 4203 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL); 4204 4205 /* Check for gaps and overlap among sections */ 4206 total = 0; 4207 expected_total = btf_data_size - hdr->hdr_len; 4208 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) { 4209 if (expected_total < secs[i].off) { 4210 btf_verifier_log(env, "Invalid section offset"); 4211 return -EINVAL; 4212 } 4213 if (total < secs[i].off) { 4214 /* gap */ 4215 btf_verifier_log(env, "Unsupported section found"); 4216 return -EINVAL; 4217 } 4218 if (total > secs[i].off) { 4219 btf_verifier_log(env, "Section overlap found"); 4220 return -EINVAL; 4221 } 4222 if (expected_total - total < secs[i].len) { 4223 btf_verifier_log(env, 4224 "Total section length too long"); 4225 return -EINVAL; 4226 } 4227 total += secs[i].len; 4228 } 4229 4230 /* There is data other than hdr and known sections */ 4231 if (expected_total != total) { 4232 btf_verifier_log(env, "Unsupported section found"); 4233 return -EINVAL; 4234 } 4235 4236 return 0; 4237 } 4238 4239 static int btf_parse_hdr(struct btf_verifier_env *env) 4240 { 4241 u32 hdr_len, hdr_copy, btf_data_size; 4242 const struct btf_header *hdr; 4243 struct btf *btf; 4244 int err; 4245 4246 btf = env->btf; 4247 btf_data_size = btf->data_size; 4248 4249 if (btf_data_size < 4250 offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) { 4251 btf_verifier_log(env, "hdr_len not found"); 4252 return -EINVAL; 4253 } 4254 4255 hdr = btf->data; 4256 hdr_len = hdr->hdr_len; 4257 if (btf_data_size < hdr_len) { 4258 btf_verifier_log(env, "btf_header not found"); 4259 return -EINVAL; 4260 } 4261 4262 /* Ensure the unsupported header fields are zero */ 4263 if (hdr_len > sizeof(btf->hdr)) { 4264 u8 *expected_zero = btf->data + sizeof(btf->hdr); 4265 u8 *end = btf->data + hdr_len; 4266 4267 for (; expected_zero < end; expected_zero++) { 4268 if (*expected_zero) { 4269 btf_verifier_log(env, "Unsupported btf_header"); 4270 return -E2BIG; 4271 } 4272 } 4273 } 4274 4275 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr)); 4276 memcpy(&btf->hdr, btf->data, hdr_copy); 4277 4278 hdr = &btf->hdr; 4279 4280 btf_verifier_log_hdr(env, btf_data_size); 4281 4282 if (hdr->magic != BTF_MAGIC) { 4283 btf_verifier_log(env, "Invalid magic"); 4284 return -EINVAL; 4285 } 4286 4287 if (hdr->version != BTF_VERSION) { 4288 btf_verifier_log(env, "Unsupported version"); 4289 return -ENOTSUPP; 4290 } 4291 4292 if (hdr->flags) { 4293 btf_verifier_log(env, "Unsupported flags"); 4294 return -ENOTSUPP; 4295 } 4296 4297 if (!btf->base_btf && btf_data_size == hdr->hdr_len) { 4298 btf_verifier_log(env, "No data"); 4299 return -EINVAL; 4300 } 4301 4302 err = btf_check_sec_info(env, btf_data_size); 4303 if (err) 4304 return err; 4305 4306 return 0; 4307 } 4308 4309 static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size, 4310 u32 log_level, char __user *log_ubuf, u32 log_size) 4311 { 4312 struct btf_verifier_env *env = NULL; 4313 struct bpf_verifier_log *log; 4314 struct btf *btf = NULL; 4315 u8 *data; 4316 int err; 4317 4318 if (btf_data_size > BTF_MAX_SIZE) 4319 return ERR_PTR(-E2BIG); 4320 4321 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); 4322 if (!env) 4323 return ERR_PTR(-ENOMEM); 4324 4325 log = &env->log; 4326 if (log_level || log_ubuf || log_size) { 4327 /* user requested verbose verifier output 4328 * and supplied buffer to store the verification trace 4329 */ 4330 log->level = log_level; 4331 log->ubuf = log_ubuf; 4332 log->len_total = log_size; 4333 4334 /* log attributes have to be sane */ 4335 if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 || 4336 !log->level || !log->ubuf) { 4337 err = -EINVAL; 4338 goto errout; 4339 } 4340 } 4341 4342 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); 4343 if (!btf) { 4344 err = -ENOMEM; 4345 goto errout; 4346 } 4347 env->btf = btf; 4348 4349 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN); 4350 if (!data) { 4351 err = -ENOMEM; 4352 goto errout; 4353 } 4354 4355 btf->data = data; 4356 btf->data_size = btf_data_size; 4357 4358 if (copy_from_bpfptr(data, btf_data, btf_data_size)) { 4359 err = -EFAULT; 4360 goto errout; 4361 } 4362 4363 err = btf_parse_hdr(env); 4364 if (err) 4365 goto errout; 4366 4367 btf->nohdr_data = btf->data + btf->hdr.hdr_len; 4368 4369 err = btf_parse_str_sec(env); 4370 if (err) 4371 goto errout; 4372 4373 err = btf_parse_type_sec(env); 4374 if (err) 4375 goto errout; 4376 4377 if (log->level && bpf_verifier_log_full(log)) { 4378 err = -ENOSPC; 4379 goto errout; 4380 } 4381 4382 btf_verifier_env_free(env); 4383 refcount_set(&btf->refcnt, 1); 4384 return btf; 4385 4386 errout: 4387 btf_verifier_env_free(env); 4388 if (btf) 4389 btf_free(btf); 4390 return ERR_PTR(err); 4391 } 4392 4393 extern char __weak __start_BTF[]; 4394 extern char __weak __stop_BTF[]; 4395 extern struct btf *btf_vmlinux; 4396 4397 #define BPF_MAP_TYPE(_id, _ops) 4398 #define BPF_LINK_TYPE(_id, _name) 4399 static union { 4400 struct bpf_ctx_convert { 4401 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ 4402 prog_ctx_type _id##_prog; \ 4403 kern_ctx_type _id##_kern; 4404 #include <linux/bpf_types.h> 4405 #undef BPF_PROG_TYPE 4406 } *__t; 4407 /* 't' is written once under lock. Read many times. */ 4408 const struct btf_type *t; 4409 } bpf_ctx_convert; 4410 enum { 4411 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ 4412 __ctx_convert##_id, 4413 #include <linux/bpf_types.h> 4414 #undef BPF_PROG_TYPE 4415 __ctx_convert_unused, /* to avoid empty enum in extreme .config */ 4416 }; 4417 static u8 bpf_ctx_convert_map[] = { 4418 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ 4419 [_id] = __ctx_convert##_id, 4420 #include <linux/bpf_types.h> 4421 #undef BPF_PROG_TYPE 4422 0, /* avoid empty array */ 4423 }; 4424 #undef BPF_MAP_TYPE 4425 #undef BPF_LINK_TYPE 4426 4427 static const struct btf_member * 4428 btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, 4429 const struct btf_type *t, enum bpf_prog_type prog_type, 4430 int arg) 4431 { 4432 const struct btf_type *conv_struct; 4433 const struct btf_type *ctx_struct; 4434 const struct btf_member *ctx_type; 4435 const char *tname, *ctx_tname; 4436 4437 conv_struct = bpf_ctx_convert.t; 4438 if (!conv_struct) { 4439 bpf_log(log, "btf_vmlinux is malformed\n"); 4440 return NULL; 4441 } 4442 t = btf_type_by_id(btf, t->type); 4443 while (btf_type_is_modifier(t)) 4444 t = btf_type_by_id(btf, t->type); 4445 if (!btf_type_is_struct(t)) { 4446 /* Only pointer to struct is supported for now. 4447 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF 4448 * is not supported yet. 4449 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine. 4450 */ 4451 return NULL; 4452 } 4453 tname = btf_name_by_offset(btf, t->name_off); 4454 if (!tname) { 4455 bpf_log(log, "arg#%d struct doesn't have a name\n", arg); 4456 return NULL; 4457 } 4458 /* prog_type is valid bpf program type. No need for bounds check. */ 4459 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2; 4460 /* ctx_struct is a pointer to prog_ctx_type in vmlinux. 4461 * Like 'struct __sk_buff' 4462 */ 4463 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type); 4464 if (!ctx_struct) 4465 /* should not happen */ 4466 return NULL; 4467 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off); 4468 if (!ctx_tname) { 4469 /* should not happen */ 4470 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n"); 4471 return NULL; 4472 } 4473 /* only compare that prog's ctx type name is the same as 4474 * kernel expects. No need to compare field by field. 4475 * It's ok for bpf prog to do: 4476 * struct __sk_buff {}; 4477 * int socket_filter_bpf_prog(struct __sk_buff *skb) 4478 * { // no fields of skb are ever used } 4479 */ 4480 if (strcmp(ctx_tname, tname)) 4481 return NULL; 4482 return ctx_type; 4483 } 4484 4485 static const struct bpf_map_ops * const btf_vmlinux_map_ops[] = { 4486 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) 4487 #define BPF_LINK_TYPE(_id, _name) 4488 #define BPF_MAP_TYPE(_id, _ops) \ 4489 [_id] = &_ops, 4490 #include <linux/bpf_types.h> 4491 #undef BPF_PROG_TYPE 4492 #undef BPF_LINK_TYPE 4493 #undef BPF_MAP_TYPE 4494 }; 4495 4496 static int btf_vmlinux_map_ids_init(const struct btf *btf, 4497 struct bpf_verifier_log *log) 4498 { 4499 const struct bpf_map_ops *ops; 4500 int i, btf_id; 4501 4502 for (i = 0; i < ARRAY_SIZE(btf_vmlinux_map_ops); ++i) { 4503 ops = btf_vmlinux_map_ops[i]; 4504 if (!ops || (!ops->map_btf_name && !ops->map_btf_id)) 4505 continue; 4506 if (!ops->map_btf_name || !ops->map_btf_id) { 4507 bpf_log(log, "map type %d is misconfigured\n", i); 4508 return -EINVAL; 4509 } 4510 btf_id = btf_find_by_name_kind(btf, ops->map_btf_name, 4511 BTF_KIND_STRUCT); 4512 if (btf_id < 0) 4513 return btf_id; 4514 *ops->map_btf_id = btf_id; 4515 } 4516 4517 return 0; 4518 } 4519 4520 static int btf_translate_to_vmlinux(struct bpf_verifier_log *log, 4521 struct btf *btf, 4522 const struct btf_type *t, 4523 enum bpf_prog_type prog_type, 4524 int arg) 4525 { 4526 const struct btf_member *prog_ctx_type, *kern_ctx_type; 4527 4528 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg); 4529 if (!prog_ctx_type) 4530 return -ENOENT; 4531 kern_ctx_type = prog_ctx_type + 1; 4532 return kern_ctx_type->type; 4533 } 4534 4535 BTF_ID_LIST(bpf_ctx_convert_btf_id) 4536 BTF_ID(struct, bpf_ctx_convert) 4537 4538 struct btf *btf_parse_vmlinux(void) 4539 { 4540 struct btf_verifier_env *env = NULL; 4541 struct bpf_verifier_log *log; 4542 struct btf *btf = NULL; 4543 int err; 4544 4545 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); 4546 if (!env) 4547 return ERR_PTR(-ENOMEM); 4548 4549 log = &env->log; 4550 log->level = BPF_LOG_KERNEL; 4551 4552 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); 4553 if (!btf) { 4554 err = -ENOMEM; 4555 goto errout; 4556 } 4557 env->btf = btf; 4558 4559 btf->data = __start_BTF; 4560 btf->data_size = __stop_BTF - __start_BTF; 4561 btf->kernel_btf = true; 4562 snprintf(btf->name, sizeof(btf->name), "vmlinux"); 4563 4564 err = btf_parse_hdr(env); 4565 if (err) 4566 goto errout; 4567 4568 btf->nohdr_data = btf->data + btf->hdr.hdr_len; 4569 4570 err = btf_parse_str_sec(env); 4571 if (err) 4572 goto errout; 4573 4574 err = btf_check_all_metas(env); 4575 if (err) 4576 goto errout; 4577 4578 /* btf_parse_vmlinux() runs under bpf_verifier_lock */ 4579 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]); 4580 4581 /* find bpf map structs for map_ptr access checking */ 4582 err = btf_vmlinux_map_ids_init(btf, log); 4583 if (err < 0) 4584 goto errout; 4585 4586 bpf_struct_ops_init(btf, log); 4587 4588 refcount_set(&btf->refcnt, 1); 4589 4590 err = btf_alloc_id(btf); 4591 if (err) 4592 goto errout; 4593 4594 btf_verifier_env_free(env); 4595 return btf; 4596 4597 errout: 4598 btf_verifier_env_free(env); 4599 if (btf) { 4600 kvfree(btf->types); 4601 kfree(btf); 4602 } 4603 return ERR_PTR(err); 4604 } 4605 4606 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES 4607 4608 static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size) 4609 { 4610 struct btf_verifier_env *env = NULL; 4611 struct bpf_verifier_log *log; 4612 struct btf *btf = NULL, *base_btf; 4613 int err; 4614 4615 base_btf = bpf_get_btf_vmlinux(); 4616 if (IS_ERR(base_btf)) 4617 return base_btf; 4618 if (!base_btf) 4619 return ERR_PTR(-EINVAL); 4620 4621 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); 4622 if (!env) 4623 return ERR_PTR(-ENOMEM); 4624 4625 log = &env->log; 4626 log->level = BPF_LOG_KERNEL; 4627 4628 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); 4629 if (!btf) { 4630 err = -ENOMEM; 4631 goto errout; 4632 } 4633 env->btf = btf; 4634 4635 btf->base_btf = base_btf; 4636 btf->start_id = base_btf->nr_types; 4637 btf->start_str_off = base_btf->hdr.str_len; 4638 btf->kernel_btf = true; 4639 snprintf(btf->name, sizeof(btf->name), "%s", module_name); 4640 4641 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN); 4642 if (!btf->data) { 4643 err = -ENOMEM; 4644 goto errout; 4645 } 4646 memcpy(btf->data, data, data_size); 4647 btf->data_size = data_size; 4648 4649 err = btf_parse_hdr(env); 4650 if (err) 4651 goto errout; 4652 4653 btf->nohdr_data = btf->data + btf->hdr.hdr_len; 4654 4655 err = btf_parse_str_sec(env); 4656 if (err) 4657 goto errout; 4658 4659 err = btf_check_all_metas(env); 4660 if (err) 4661 goto errout; 4662 4663 btf_verifier_env_free(env); 4664 refcount_set(&btf->refcnt, 1); 4665 return btf; 4666 4667 errout: 4668 btf_verifier_env_free(env); 4669 if (btf) { 4670 kvfree(btf->data); 4671 kvfree(btf->types); 4672 kfree(btf); 4673 } 4674 return ERR_PTR(err); 4675 } 4676 4677 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */ 4678 4679 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog) 4680 { 4681 struct bpf_prog *tgt_prog = prog->aux->dst_prog; 4682 4683 if (tgt_prog) 4684 return tgt_prog->aux->btf; 4685 else 4686 return prog->aux->attach_btf; 4687 } 4688 4689 static bool is_string_ptr(struct btf *btf, const struct btf_type *t) 4690 { 4691 /* t comes in already as a pointer */ 4692 t = btf_type_by_id(btf, t->type); 4693 4694 /* allow const */ 4695 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST) 4696 t = btf_type_by_id(btf, t->type); 4697 4698 /* char, signed char, unsigned char */ 4699 return btf_type_is_int(t) && t->size == 1; 4700 } 4701 4702 bool btf_ctx_access(int off, int size, enum bpf_access_type type, 4703 const struct bpf_prog *prog, 4704 struct bpf_insn_access_aux *info) 4705 { 4706 const struct btf_type *t = prog->aux->attach_func_proto; 4707 struct bpf_prog *tgt_prog = prog->aux->dst_prog; 4708 struct btf *btf = bpf_prog_get_target_btf(prog); 4709 const char *tname = prog->aux->attach_func_name; 4710 struct bpf_verifier_log *log = info->log; 4711 const struct btf_param *args; 4712 u32 nr_args, arg; 4713 int i, ret; 4714 4715 if (off % 8) { 4716 bpf_log(log, "func '%s' offset %d is not multiple of 8\n", 4717 tname, off); 4718 return false; 4719 } 4720 arg = off / 8; 4721 args = (const struct btf_param *)(t + 1); 4722 /* if (t == NULL) Fall back to default BPF prog with 4723 * MAX_BPF_FUNC_REG_ARGS u64 arguments. 4724 */ 4725 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS; 4726 if (prog->aux->attach_btf_trace) { 4727 /* skip first 'void *__data' argument in btf_trace_##name typedef */ 4728 args++; 4729 nr_args--; 4730 } 4731 4732 if (arg > nr_args) { 4733 bpf_log(log, "func '%s' doesn't have %d-th argument\n", 4734 tname, arg + 1); 4735 return false; 4736 } 4737 4738 if (arg == nr_args) { 4739 switch (prog->expected_attach_type) { 4740 case BPF_LSM_MAC: 4741 case BPF_TRACE_FEXIT: 4742 /* When LSM programs are attached to void LSM hooks 4743 * they use FEXIT trampolines and when attached to 4744 * int LSM hooks, they use MODIFY_RETURN trampolines. 4745 * 4746 * While the LSM programs are BPF_MODIFY_RETURN-like 4747 * the check: 4748 * 4749 * if (ret_type != 'int') 4750 * return -EINVAL; 4751 * 4752 * is _not_ done here. This is still safe as LSM hooks 4753 * have only void and int return types. 4754 */ 4755 if (!t) 4756 return true; 4757 t = btf_type_by_id(btf, t->type); 4758 break; 4759 case BPF_MODIFY_RETURN: 4760 /* For now the BPF_MODIFY_RETURN can only be attached to 4761 * functions that return an int. 4762 */ 4763 if (!t) 4764 return false; 4765 4766 t = btf_type_skip_modifiers(btf, t->type, NULL); 4767 if (!btf_type_is_small_int(t)) { 4768 bpf_log(log, 4769 "ret type %s not allowed for fmod_ret\n", 4770 btf_kind_str[BTF_INFO_KIND(t->info)]); 4771 return false; 4772 } 4773 break; 4774 default: 4775 bpf_log(log, "func '%s' doesn't have %d-th argument\n", 4776 tname, arg + 1); 4777 return false; 4778 } 4779 } else { 4780 if (!t) 4781 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */ 4782 return true; 4783 t = btf_type_by_id(btf, args[arg].type); 4784 } 4785 4786 /* skip modifiers */ 4787 while (btf_type_is_modifier(t)) 4788 t = btf_type_by_id(btf, t->type); 4789 if (btf_type_is_small_int(t) || btf_type_is_enum(t)) 4790 /* accessing a scalar */ 4791 return true; 4792 if (!btf_type_is_ptr(t)) { 4793 bpf_log(log, 4794 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n", 4795 tname, arg, 4796 __btf_name_by_offset(btf, t->name_off), 4797 btf_kind_str[BTF_INFO_KIND(t->info)]); 4798 return false; 4799 } 4800 4801 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */ 4802 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) { 4803 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i]; 4804 4805 if (ctx_arg_info->offset == off && 4806 (ctx_arg_info->reg_type == PTR_TO_RDONLY_BUF_OR_NULL || 4807 ctx_arg_info->reg_type == PTR_TO_RDWR_BUF_OR_NULL)) { 4808 info->reg_type = ctx_arg_info->reg_type; 4809 return true; 4810 } 4811 } 4812 4813 if (t->type == 0) 4814 /* This is a pointer to void. 4815 * It is the same as scalar from the verifier safety pov. 4816 * No further pointer walking is allowed. 4817 */ 4818 return true; 4819 4820 if (is_string_ptr(btf, t)) 4821 return true; 4822 4823 /* this is a pointer to another type */ 4824 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) { 4825 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i]; 4826 4827 if (ctx_arg_info->offset == off) { 4828 if (!ctx_arg_info->btf_id) { 4829 bpf_log(log,"invalid btf_id for context argument offset %u\n", off); 4830 return false; 4831 } 4832 4833 info->reg_type = ctx_arg_info->reg_type; 4834 info->btf = btf_vmlinux; 4835 info->btf_id = ctx_arg_info->btf_id; 4836 return true; 4837 } 4838 } 4839 4840 info->reg_type = PTR_TO_BTF_ID; 4841 if (tgt_prog) { 4842 enum bpf_prog_type tgt_type; 4843 4844 if (tgt_prog->type == BPF_PROG_TYPE_EXT) 4845 tgt_type = tgt_prog->aux->saved_dst_prog_type; 4846 else 4847 tgt_type = tgt_prog->type; 4848 4849 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg); 4850 if (ret > 0) { 4851 info->btf = btf_vmlinux; 4852 info->btf_id = ret; 4853 return true; 4854 } else { 4855 return false; 4856 } 4857 } 4858 4859 info->btf = btf; 4860 info->btf_id = t->type; 4861 t = btf_type_by_id(btf, t->type); 4862 /* skip modifiers */ 4863 while (btf_type_is_modifier(t)) { 4864 info->btf_id = t->type; 4865 t = btf_type_by_id(btf, t->type); 4866 } 4867 if (!btf_type_is_struct(t)) { 4868 bpf_log(log, 4869 "func '%s' arg%d type %s is not a struct\n", 4870 tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]); 4871 return false; 4872 } 4873 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n", 4874 tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)], 4875 __btf_name_by_offset(btf, t->name_off)); 4876 return true; 4877 } 4878 4879 enum bpf_struct_walk_result { 4880 /* < 0 error */ 4881 WALK_SCALAR = 0, 4882 WALK_PTR, 4883 WALK_STRUCT, 4884 }; 4885 4886 static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, 4887 const struct btf_type *t, int off, int size, 4888 u32 *next_btf_id) 4889 { 4890 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0; 4891 const struct btf_type *mtype, *elem_type = NULL; 4892 const struct btf_member *member; 4893 const char *tname, *mname; 4894 u32 vlen, elem_id, mid; 4895 4896 again: 4897 tname = __btf_name_by_offset(btf, t->name_off); 4898 if (!btf_type_is_struct(t)) { 4899 bpf_log(log, "Type '%s' is not a struct\n", tname); 4900 return -EINVAL; 4901 } 4902 4903 vlen = btf_type_vlen(t); 4904 if (off + size > t->size) { 4905 /* If the last element is a variable size array, we may 4906 * need to relax the rule. 4907 */ 4908 struct btf_array *array_elem; 4909 4910 if (vlen == 0) 4911 goto error; 4912 4913 member = btf_type_member(t) + vlen - 1; 4914 mtype = btf_type_skip_modifiers(btf, member->type, 4915 NULL); 4916 if (!btf_type_is_array(mtype)) 4917 goto error; 4918 4919 array_elem = (struct btf_array *)(mtype + 1); 4920 if (array_elem->nelems != 0) 4921 goto error; 4922 4923 moff = btf_member_bit_offset(t, member) / 8; 4924 if (off < moff) 4925 goto error; 4926 4927 /* Only allow structure for now, can be relaxed for 4928 * other types later. 4929 */ 4930 t = btf_type_skip_modifiers(btf, array_elem->type, 4931 NULL); 4932 if (!btf_type_is_struct(t)) 4933 goto error; 4934 4935 off = (off - moff) % t->size; 4936 goto again; 4937 4938 error: 4939 bpf_log(log, "access beyond struct %s at off %u size %u\n", 4940 tname, off, size); 4941 return -EACCES; 4942 } 4943 4944 for_each_member(i, t, member) { 4945 /* offset of the field in bytes */ 4946 moff = btf_member_bit_offset(t, member) / 8; 4947 if (off + size <= moff) 4948 /* won't find anything, field is already too far */ 4949 break; 4950 4951 if (btf_member_bitfield_size(t, member)) { 4952 u32 end_bit = btf_member_bit_offset(t, member) + 4953 btf_member_bitfield_size(t, member); 4954 4955 /* off <= moff instead of off == moff because clang 4956 * does not generate a BTF member for anonymous 4957 * bitfield like the ":16" here: 4958 * struct { 4959 * int :16; 4960 * int x:8; 4961 * }; 4962 */ 4963 if (off <= moff && 4964 BITS_ROUNDUP_BYTES(end_bit) <= off + size) 4965 return WALK_SCALAR; 4966 4967 /* off may be accessing a following member 4968 * 4969 * or 4970 * 4971 * Doing partial access at either end of this 4972 * bitfield. Continue on this case also to 4973 * treat it as not accessing this bitfield 4974 * and eventually error out as field not 4975 * found to keep it simple. 4976 * It could be relaxed if there was a legit 4977 * partial access case later. 4978 */ 4979 continue; 4980 } 4981 4982 /* In case of "off" is pointing to holes of a struct */ 4983 if (off < moff) 4984 break; 4985 4986 /* type of the field */ 4987 mid = member->type; 4988 mtype = btf_type_by_id(btf, member->type); 4989 mname = __btf_name_by_offset(btf, member->name_off); 4990 4991 mtype = __btf_resolve_size(btf, mtype, &msize, 4992 &elem_type, &elem_id, &total_nelems, 4993 &mid); 4994 if (IS_ERR(mtype)) { 4995 bpf_log(log, "field %s doesn't have size\n", mname); 4996 return -EFAULT; 4997 } 4998 4999 mtrue_end = moff + msize; 5000 if (off >= mtrue_end) 5001 /* no overlap with member, keep iterating */ 5002 continue; 5003 5004 if (btf_type_is_array(mtype)) { 5005 u32 elem_idx; 5006 5007 /* __btf_resolve_size() above helps to 5008 * linearize a multi-dimensional array. 5009 * 5010 * The logic here is treating an array 5011 * in a struct as the following way: 5012 * 5013 * struct outer { 5014 * struct inner array[2][2]; 5015 * }; 5016 * 5017 * looks like: 5018 * 5019 * struct outer { 5020 * struct inner array_elem0; 5021 * struct inner array_elem1; 5022 * struct inner array_elem2; 5023 * struct inner array_elem3; 5024 * }; 5025 * 5026 * When accessing outer->array[1][0], it moves 5027 * moff to "array_elem2", set mtype to 5028 * "struct inner", and msize also becomes 5029 * sizeof(struct inner). Then most of the 5030 * remaining logic will fall through without 5031 * caring the current member is an array or 5032 * not. 5033 * 5034 * Unlike mtype/msize/moff, mtrue_end does not 5035 * change. The naming difference ("_true") tells 5036 * that it is not always corresponding to 5037 * the current mtype/msize/moff. 5038 * It is the true end of the current 5039 * member (i.e. array in this case). That 5040 * will allow an int array to be accessed like 5041 * a scratch space, 5042 * i.e. allow access beyond the size of 5043 * the array's element as long as it is 5044 * within the mtrue_end boundary. 5045 */ 5046 5047 /* skip empty array */ 5048 if (moff == mtrue_end) 5049 continue; 5050 5051 msize /= total_nelems; 5052 elem_idx = (off - moff) / msize; 5053 moff += elem_idx * msize; 5054 mtype = elem_type; 5055 mid = elem_id; 5056 } 5057 5058 /* the 'off' we're looking for is either equal to start 5059 * of this field or inside of this struct 5060 */ 5061 if (btf_type_is_struct(mtype)) { 5062 /* our field must be inside that union or struct */ 5063 t = mtype; 5064 5065 /* return if the offset matches the member offset */ 5066 if (off == moff) { 5067 *next_btf_id = mid; 5068 return WALK_STRUCT; 5069 } 5070 5071 /* adjust offset we're looking for */ 5072 off -= moff; 5073 goto again; 5074 } 5075 5076 if (btf_type_is_ptr(mtype)) { 5077 const struct btf_type *stype; 5078 u32 id; 5079 5080 if (msize != size || off != moff) { 5081 bpf_log(log, 5082 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n", 5083 mname, moff, tname, off, size); 5084 return -EACCES; 5085 } 5086 stype = btf_type_skip_modifiers(btf, mtype->type, &id); 5087 if (btf_type_is_struct(stype)) { 5088 *next_btf_id = id; 5089 return WALK_PTR; 5090 } 5091 } 5092 5093 /* Allow more flexible access within an int as long as 5094 * it is within mtrue_end. 5095 * Since mtrue_end could be the end of an array, 5096 * that also allows using an array of int as a scratch 5097 * space. e.g. skb->cb[]. 5098 */ 5099 if (off + size > mtrue_end) { 5100 bpf_log(log, 5101 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n", 5102 mname, mtrue_end, tname, off, size); 5103 return -EACCES; 5104 } 5105 5106 return WALK_SCALAR; 5107 } 5108 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off); 5109 return -EINVAL; 5110 } 5111 5112 int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, 5113 const struct btf_type *t, int off, int size, 5114 enum bpf_access_type atype __maybe_unused, 5115 u32 *next_btf_id) 5116 { 5117 int err; 5118 u32 id; 5119 5120 do { 5121 err = btf_struct_walk(log, btf, t, off, size, &id); 5122 5123 switch (err) { 5124 case WALK_PTR: 5125 /* If we found the pointer or scalar on t+off, 5126 * we're done. 5127 */ 5128 *next_btf_id = id; 5129 return PTR_TO_BTF_ID; 5130 case WALK_SCALAR: 5131 return SCALAR_VALUE; 5132 case WALK_STRUCT: 5133 /* We found nested struct, so continue the search 5134 * by diving in it. At this point the offset is 5135 * aligned with the new type, so set it to 0. 5136 */ 5137 t = btf_type_by_id(btf, id); 5138 off = 0; 5139 break; 5140 default: 5141 /* It's either error or unknown return value.. 5142 * scream and leave. 5143 */ 5144 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value")) 5145 return -EINVAL; 5146 return err; 5147 } 5148 } while (t); 5149 5150 return -EINVAL; 5151 } 5152 5153 /* Check that two BTF types, each specified as an BTF object + id, are exactly 5154 * the same. Trivial ID check is not enough due to module BTFs, because we can 5155 * end up with two different module BTFs, but IDs point to the common type in 5156 * vmlinux BTF. 5157 */ 5158 static bool btf_types_are_same(const struct btf *btf1, u32 id1, 5159 const struct btf *btf2, u32 id2) 5160 { 5161 if (id1 != id2) 5162 return false; 5163 if (btf1 == btf2) 5164 return true; 5165 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2); 5166 } 5167 5168 bool btf_struct_ids_match(struct bpf_verifier_log *log, 5169 const struct btf *btf, u32 id, int off, 5170 const struct btf *need_btf, u32 need_type_id) 5171 { 5172 const struct btf_type *type; 5173 int err; 5174 5175 /* Are we already done? */ 5176 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id)) 5177 return true; 5178 5179 again: 5180 type = btf_type_by_id(btf, id); 5181 if (!type) 5182 return false; 5183 err = btf_struct_walk(log, btf, type, off, 1, &id); 5184 if (err != WALK_STRUCT) 5185 return false; 5186 5187 /* We found nested struct object. If it matches 5188 * the requested ID, we're done. Otherwise let's 5189 * continue the search with offset 0 in the new 5190 * type. 5191 */ 5192 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) { 5193 off = 0; 5194 goto again; 5195 } 5196 5197 return true; 5198 } 5199 5200 static int __get_type_size(struct btf *btf, u32 btf_id, 5201 const struct btf_type **bad_type) 5202 { 5203 const struct btf_type *t; 5204 5205 if (!btf_id) 5206 /* void */ 5207 return 0; 5208 t = btf_type_by_id(btf, btf_id); 5209 while (t && btf_type_is_modifier(t)) 5210 t = btf_type_by_id(btf, t->type); 5211 if (!t) { 5212 *bad_type = btf_type_by_id(btf, 0); 5213 return -EINVAL; 5214 } 5215 if (btf_type_is_ptr(t)) 5216 /* kernel size of pointer. Not BPF's size of pointer*/ 5217 return sizeof(void *); 5218 if (btf_type_is_int(t) || btf_type_is_enum(t)) 5219 return t->size; 5220 *bad_type = t; 5221 return -EINVAL; 5222 } 5223 5224 int btf_distill_func_proto(struct bpf_verifier_log *log, 5225 struct btf *btf, 5226 const struct btf_type *func, 5227 const char *tname, 5228 struct btf_func_model *m) 5229 { 5230 const struct btf_param *args; 5231 const struct btf_type *t; 5232 u32 i, nargs; 5233 int ret; 5234 5235 if (!func) { 5236 /* BTF function prototype doesn't match the verifier types. 5237 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args. 5238 */ 5239 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) 5240 m->arg_size[i] = 8; 5241 m->ret_size = 8; 5242 m->nr_args = MAX_BPF_FUNC_REG_ARGS; 5243 return 0; 5244 } 5245 args = (const struct btf_param *)(func + 1); 5246 nargs = btf_type_vlen(func); 5247 if (nargs >= MAX_BPF_FUNC_ARGS) { 5248 bpf_log(log, 5249 "The function %s has %d arguments. Too many.\n", 5250 tname, nargs); 5251 return -EINVAL; 5252 } 5253 ret = __get_type_size(btf, func->type, &t); 5254 if (ret < 0) { 5255 bpf_log(log, 5256 "The function %s return type %s is unsupported.\n", 5257 tname, btf_kind_str[BTF_INFO_KIND(t->info)]); 5258 return -EINVAL; 5259 } 5260 m->ret_size = ret; 5261 5262 for (i = 0; i < nargs; i++) { 5263 if (i == nargs - 1 && args[i].type == 0) { 5264 bpf_log(log, 5265 "The function %s with variable args is unsupported.\n", 5266 tname); 5267 return -EINVAL; 5268 } 5269 ret = __get_type_size(btf, args[i].type, &t); 5270 if (ret < 0) { 5271 bpf_log(log, 5272 "The function %s arg%d type %s is unsupported.\n", 5273 tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]); 5274 return -EINVAL; 5275 } 5276 if (ret == 0) { 5277 bpf_log(log, 5278 "The function %s has malformed void argument.\n", 5279 tname); 5280 return -EINVAL; 5281 } 5282 m->arg_size[i] = ret; 5283 } 5284 m->nr_args = nargs; 5285 return 0; 5286 } 5287 5288 /* Compare BTFs of two functions assuming only scalars and pointers to context. 5289 * t1 points to BTF_KIND_FUNC in btf1 5290 * t2 points to BTF_KIND_FUNC in btf2 5291 * Returns: 5292 * EINVAL - function prototype mismatch 5293 * EFAULT - verifier bug 5294 * 0 - 99% match. The last 1% is validated by the verifier. 5295 */ 5296 static int btf_check_func_type_match(struct bpf_verifier_log *log, 5297 struct btf *btf1, const struct btf_type *t1, 5298 struct btf *btf2, const struct btf_type *t2) 5299 { 5300 const struct btf_param *args1, *args2; 5301 const char *fn1, *fn2, *s1, *s2; 5302 u32 nargs1, nargs2, i; 5303 5304 fn1 = btf_name_by_offset(btf1, t1->name_off); 5305 fn2 = btf_name_by_offset(btf2, t2->name_off); 5306 5307 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) { 5308 bpf_log(log, "%s() is not a global function\n", fn1); 5309 return -EINVAL; 5310 } 5311 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) { 5312 bpf_log(log, "%s() is not a global function\n", fn2); 5313 return -EINVAL; 5314 } 5315 5316 t1 = btf_type_by_id(btf1, t1->type); 5317 if (!t1 || !btf_type_is_func_proto(t1)) 5318 return -EFAULT; 5319 t2 = btf_type_by_id(btf2, t2->type); 5320 if (!t2 || !btf_type_is_func_proto(t2)) 5321 return -EFAULT; 5322 5323 args1 = (const struct btf_param *)(t1 + 1); 5324 nargs1 = btf_type_vlen(t1); 5325 args2 = (const struct btf_param *)(t2 + 1); 5326 nargs2 = btf_type_vlen(t2); 5327 5328 if (nargs1 != nargs2) { 5329 bpf_log(log, "%s() has %d args while %s() has %d args\n", 5330 fn1, nargs1, fn2, nargs2); 5331 return -EINVAL; 5332 } 5333 5334 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL); 5335 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL); 5336 if (t1->info != t2->info) { 5337 bpf_log(log, 5338 "Return type %s of %s() doesn't match type %s of %s()\n", 5339 btf_type_str(t1), fn1, 5340 btf_type_str(t2), fn2); 5341 return -EINVAL; 5342 } 5343 5344 for (i = 0; i < nargs1; i++) { 5345 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL); 5346 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL); 5347 5348 if (t1->info != t2->info) { 5349 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n", 5350 i, fn1, btf_type_str(t1), 5351 fn2, btf_type_str(t2)); 5352 return -EINVAL; 5353 } 5354 if (btf_type_has_size(t1) && t1->size != t2->size) { 5355 bpf_log(log, 5356 "arg%d in %s() has size %d while %s() has %d\n", 5357 i, fn1, t1->size, 5358 fn2, t2->size); 5359 return -EINVAL; 5360 } 5361 5362 /* global functions are validated with scalars and pointers 5363 * to context only. And only global functions can be replaced. 5364 * Hence type check only those types. 5365 */ 5366 if (btf_type_is_int(t1) || btf_type_is_enum(t1)) 5367 continue; 5368 if (!btf_type_is_ptr(t1)) { 5369 bpf_log(log, 5370 "arg%d in %s() has unrecognized type\n", 5371 i, fn1); 5372 return -EINVAL; 5373 } 5374 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL); 5375 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL); 5376 if (!btf_type_is_struct(t1)) { 5377 bpf_log(log, 5378 "arg%d in %s() is not a pointer to context\n", 5379 i, fn1); 5380 return -EINVAL; 5381 } 5382 if (!btf_type_is_struct(t2)) { 5383 bpf_log(log, 5384 "arg%d in %s() is not a pointer to context\n", 5385 i, fn2); 5386 return -EINVAL; 5387 } 5388 /* This is an optional check to make program writing easier. 5389 * Compare names of structs and report an error to the user. 5390 * btf_prepare_func_args() already checked that t2 struct 5391 * is a context type. btf_prepare_func_args() will check 5392 * later that t1 struct is a context type as well. 5393 */ 5394 s1 = btf_name_by_offset(btf1, t1->name_off); 5395 s2 = btf_name_by_offset(btf2, t2->name_off); 5396 if (strcmp(s1, s2)) { 5397 bpf_log(log, 5398 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n", 5399 i, fn1, s1, fn2, s2); 5400 return -EINVAL; 5401 } 5402 } 5403 return 0; 5404 } 5405 5406 /* Compare BTFs of given program with BTF of target program */ 5407 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog, 5408 struct btf *btf2, const struct btf_type *t2) 5409 { 5410 struct btf *btf1 = prog->aux->btf; 5411 const struct btf_type *t1; 5412 u32 btf_id = 0; 5413 5414 if (!prog->aux->func_info) { 5415 bpf_log(log, "Program extension requires BTF\n"); 5416 return -EINVAL; 5417 } 5418 5419 btf_id = prog->aux->func_info[0].type_id; 5420 if (!btf_id) 5421 return -EFAULT; 5422 5423 t1 = btf_type_by_id(btf1, btf_id); 5424 if (!t1 || !btf_type_is_func(t1)) 5425 return -EFAULT; 5426 5427 return btf_check_func_type_match(log, btf1, t1, btf2, t2); 5428 } 5429 5430 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = { 5431 #ifdef CONFIG_NET 5432 [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK], 5433 [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], 5434 [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP], 5435 #endif 5436 }; 5437 5438 static int btf_check_func_arg_match(struct bpf_verifier_env *env, 5439 const struct btf *btf, u32 func_id, 5440 struct bpf_reg_state *regs, 5441 bool ptr_to_mem_ok) 5442 { 5443 struct bpf_verifier_log *log = &env->log; 5444 const char *func_name, *ref_tname; 5445 const struct btf_type *t, *ref_t; 5446 const struct btf_param *args; 5447 u32 i, nargs, ref_id; 5448 5449 t = btf_type_by_id(btf, func_id); 5450 if (!t || !btf_type_is_func(t)) { 5451 /* These checks were already done by the verifier while loading 5452 * struct bpf_func_info or in add_kfunc_call(). 5453 */ 5454 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n", 5455 func_id); 5456 return -EFAULT; 5457 } 5458 func_name = btf_name_by_offset(btf, t->name_off); 5459 5460 t = btf_type_by_id(btf, t->type); 5461 if (!t || !btf_type_is_func_proto(t)) { 5462 bpf_log(log, "Invalid BTF of func %s\n", func_name); 5463 return -EFAULT; 5464 } 5465 args = (const struct btf_param *)(t + 1); 5466 nargs = btf_type_vlen(t); 5467 if (nargs > MAX_BPF_FUNC_REG_ARGS) { 5468 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs, 5469 MAX_BPF_FUNC_REG_ARGS); 5470 return -EINVAL; 5471 } 5472 5473 /* check that BTF function arguments match actual types that the 5474 * verifier sees. 5475 */ 5476 for (i = 0; i < nargs; i++) { 5477 u32 regno = i + 1; 5478 struct bpf_reg_state *reg = ®s[regno]; 5479 5480 t = btf_type_skip_modifiers(btf, args[i].type, NULL); 5481 if (btf_type_is_scalar(t)) { 5482 if (reg->type == SCALAR_VALUE) 5483 continue; 5484 bpf_log(log, "R%d is not a scalar\n", regno); 5485 return -EINVAL; 5486 } 5487 5488 if (!btf_type_is_ptr(t)) { 5489 bpf_log(log, "Unrecognized arg#%d type %s\n", 5490 i, btf_type_str(t)); 5491 return -EINVAL; 5492 } 5493 5494 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id); 5495 ref_tname = btf_name_by_offset(btf, ref_t->name_off); 5496 if (btf_is_kernel(btf)) { 5497 const struct btf_type *reg_ref_t; 5498 const struct btf *reg_btf; 5499 const char *reg_ref_tname; 5500 u32 reg_ref_id; 5501 5502 if (!btf_type_is_struct(ref_t)) { 5503 bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n", 5504 func_name, i, btf_type_str(ref_t), 5505 ref_tname); 5506 return -EINVAL; 5507 } 5508 5509 if (reg->type == PTR_TO_BTF_ID) { 5510 reg_btf = reg->btf; 5511 reg_ref_id = reg->btf_id; 5512 } else if (reg2btf_ids[reg->type]) { 5513 reg_btf = btf_vmlinux; 5514 reg_ref_id = *reg2btf_ids[reg->type]; 5515 } else { 5516 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d is not a pointer to btf_id\n", 5517 func_name, i, 5518 btf_type_str(ref_t), ref_tname, regno); 5519 return -EINVAL; 5520 } 5521 5522 reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, 5523 ®_ref_id); 5524 reg_ref_tname = btf_name_by_offset(reg_btf, 5525 reg_ref_t->name_off); 5526 if (!btf_struct_ids_match(log, reg_btf, reg_ref_id, 5527 reg->off, btf, ref_id)) { 5528 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n", 5529 func_name, i, 5530 btf_type_str(ref_t), ref_tname, 5531 regno, btf_type_str(reg_ref_t), 5532 reg_ref_tname); 5533 return -EINVAL; 5534 } 5535 } else if (btf_get_prog_ctx_type(log, btf, t, 5536 env->prog->type, i)) { 5537 /* If function expects ctx type in BTF check that caller 5538 * is passing PTR_TO_CTX. 5539 */ 5540 if (reg->type != PTR_TO_CTX) { 5541 bpf_log(log, 5542 "arg#%d expected pointer to ctx, but got %s\n", 5543 i, btf_type_str(t)); 5544 return -EINVAL; 5545 } 5546 if (check_ctx_reg(env, reg, regno)) 5547 return -EINVAL; 5548 } else if (ptr_to_mem_ok) { 5549 const struct btf_type *resolve_ret; 5550 u32 type_size; 5551 5552 resolve_ret = btf_resolve_size(btf, ref_t, &type_size); 5553 if (IS_ERR(resolve_ret)) { 5554 bpf_log(log, 5555 "arg#%d reference type('%s %s') size cannot be determined: %ld\n", 5556 i, btf_type_str(ref_t), ref_tname, 5557 PTR_ERR(resolve_ret)); 5558 return -EINVAL; 5559 } 5560 5561 if (check_mem_reg(env, reg, regno, type_size)) 5562 return -EINVAL; 5563 } else { 5564 return -EINVAL; 5565 } 5566 } 5567 5568 return 0; 5569 } 5570 5571 /* Compare BTF of a function with given bpf_reg_state. 5572 * Returns: 5573 * EFAULT - there is a verifier bug. Abort verification. 5574 * EINVAL - there is a type mismatch or BTF is not available. 5575 * 0 - BTF matches with what bpf_reg_state expects. 5576 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized. 5577 */ 5578 int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog, 5579 struct bpf_reg_state *regs) 5580 { 5581 struct bpf_prog *prog = env->prog; 5582 struct btf *btf = prog->aux->btf; 5583 bool is_global; 5584 u32 btf_id; 5585 int err; 5586 5587 if (!prog->aux->func_info) 5588 return -EINVAL; 5589 5590 btf_id = prog->aux->func_info[subprog].type_id; 5591 if (!btf_id) 5592 return -EFAULT; 5593 5594 if (prog->aux->func_info_aux[subprog].unreliable) 5595 return -EINVAL; 5596 5597 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; 5598 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global); 5599 5600 /* Compiler optimizations can remove arguments from static functions 5601 * or mismatched type can be passed into a global function. 5602 * In such cases mark the function as unreliable from BTF point of view. 5603 */ 5604 if (err) 5605 prog->aux->func_info_aux[subprog].unreliable = true; 5606 return err; 5607 } 5608 5609 int btf_check_kfunc_arg_match(struct bpf_verifier_env *env, 5610 const struct btf *btf, u32 func_id, 5611 struct bpf_reg_state *regs) 5612 { 5613 return btf_check_func_arg_match(env, btf, func_id, regs, false); 5614 } 5615 5616 /* Convert BTF of a function into bpf_reg_state if possible 5617 * Returns: 5618 * EFAULT - there is a verifier bug. Abort verification. 5619 * EINVAL - cannot convert BTF. 5620 * 0 - Successfully converted BTF into bpf_reg_state 5621 * (either PTR_TO_CTX or SCALAR_VALUE). 5622 */ 5623 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, 5624 struct bpf_reg_state *regs) 5625 { 5626 struct bpf_verifier_log *log = &env->log; 5627 struct bpf_prog *prog = env->prog; 5628 enum bpf_prog_type prog_type = prog->type; 5629 struct btf *btf = prog->aux->btf; 5630 const struct btf_param *args; 5631 const struct btf_type *t, *ref_t; 5632 u32 i, nargs, btf_id; 5633 const char *tname; 5634 5635 if (!prog->aux->func_info || 5636 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) { 5637 bpf_log(log, "Verifier bug\n"); 5638 return -EFAULT; 5639 } 5640 5641 btf_id = prog->aux->func_info[subprog].type_id; 5642 if (!btf_id) { 5643 bpf_log(log, "Global functions need valid BTF\n"); 5644 return -EFAULT; 5645 } 5646 5647 t = btf_type_by_id(btf, btf_id); 5648 if (!t || !btf_type_is_func(t)) { 5649 /* These checks were already done by the verifier while loading 5650 * struct bpf_func_info 5651 */ 5652 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n", 5653 subprog); 5654 return -EFAULT; 5655 } 5656 tname = btf_name_by_offset(btf, t->name_off); 5657 5658 if (log->level & BPF_LOG_LEVEL) 5659 bpf_log(log, "Validating %s() func#%d...\n", 5660 tname, subprog); 5661 5662 if (prog->aux->func_info_aux[subprog].unreliable) { 5663 bpf_log(log, "Verifier bug in function %s()\n", tname); 5664 return -EFAULT; 5665 } 5666 if (prog_type == BPF_PROG_TYPE_EXT) 5667 prog_type = prog->aux->dst_prog->type; 5668 5669 t = btf_type_by_id(btf, t->type); 5670 if (!t || !btf_type_is_func_proto(t)) { 5671 bpf_log(log, "Invalid type of function %s()\n", tname); 5672 return -EFAULT; 5673 } 5674 args = (const struct btf_param *)(t + 1); 5675 nargs = btf_type_vlen(t); 5676 if (nargs > MAX_BPF_FUNC_REG_ARGS) { 5677 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n", 5678 tname, nargs, MAX_BPF_FUNC_REG_ARGS); 5679 return -EINVAL; 5680 } 5681 /* check that function returns int */ 5682 t = btf_type_by_id(btf, t->type); 5683 while (btf_type_is_modifier(t)) 5684 t = btf_type_by_id(btf, t->type); 5685 if (!btf_type_is_int(t) && !btf_type_is_enum(t)) { 5686 bpf_log(log, 5687 "Global function %s() doesn't return scalar. Only those are supported.\n", 5688 tname); 5689 return -EINVAL; 5690 } 5691 /* Convert BTF function arguments into verifier types. 5692 * Only PTR_TO_CTX and SCALAR are supported atm. 5693 */ 5694 for (i = 0; i < nargs; i++) { 5695 struct bpf_reg_state *reg = ®s[i + 1]; 5696 5697 t = btf_type_by_id(btf, args[i].type); 5698 while (btf_type_is_modifier(t)) 5699 t = btf_type_by_id(btf, t->type); 5700 if (btf_type_is_int(t) || btf_type_is_enum(t)) { 5701 reg->type = SCALAR_VALUE; 5702 continue; 5703 } 5704 if (btf_type_is_ptr(t)) { 5705 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) { 5706 reg->type = PTR_TO_CTX; 5707 continue; 5708 } 5709 5710 t = btf_type_skip_modifiers(btf, t->type, NULL); 5711 5712 ref_t = btf_resolve_size(btf, t, ®->mem_size); 5713 if (IS_ERR(ref_t)) { 5714 bpf_log(log, 5715 "arg#%d reference type('%s %s') size cannot be determined: %ld\n", 5716 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off), 5717 PTR_ERR(ref_t)); 5718 return -EINVAL; 5719 } 5720 5721 reg->type = PTR_TO_MEM_OR_NULL; 5722 reg->id = ++env->id_gen; 5723 5724 continue; 5725 } 5726 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n", 5727 i, btf_kind_str[BTF_INFO_KIND(t->info)], tname); 5728 return -EINVAL; 5729 } 5730 return 0; 5731 } 5732 5733 static void btf_type_show(const struct btf *btf, u32 type_id, void *obj, 5734 struct btf_show *show) 5735 { 5736 const struct btf_type *t = btf_type_by_id(btf, type_id); 5737 5738 show->btf = btf; 5739 memset(&show->state, 0, sizeof(show->state)); 5740 memset(&show->obj, 0, sizeof(show->obj)); 5741 5742 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show); 5743 } 5744 5745 static void btf_seq_show(struct btf_show *show, const char *fmt, 5746 va_list args) 5747 { 5748 seq_vprintf((struct seq_file *)show->target, fmt, args); 5749 } 5750 5751 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id, 5752 void *obj, struct seq_file *m, u64 flags) 5753 { 5754 struct btf_show sseq; 5755 5756 sseq.target = m; 5757 sseq.showfn = btf_seq_show; 5758 sseq.flags = flags; 5759 5760 btf_type_show(btf, type_id, obj, &sseq); 5761 5762 return sseq.state.status; 5763 } 5764 5765 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj, 5766 struct seq_file *m) 5767 { 5768 (void) btf_type_seq_show_flags(btf, type_id, obj, m, 5769 BTF_SHOW_NONAME | BTF_SHOW_COMPACT | 5770 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE); 5771 } 5772 5773 struct btf_show_snprintf { 5774 struct btf_show show; 5775 int len_left; /* space left in string */ 5776 int len; /* length we would have written */ 5777 }; 5778 5779 static void btf_snprintf_show(struct btf_show *show, const char *fmt, 5780 va_list args) 5781 { 5782 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show; 5783 int len; 5784 5785 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args); 5786 5787 if (len < 0) { 5788 ssnprintf->len_left = 0; 5789 ssnprintf->len = len; 5790 } else if (len > ssnprintf->len_left) { 5791 /* no space, drive on to get length we would have written */ 5792 ssnprintf->len_left = 0; 5793 ssnprintf->len += len; 5794 } else { 5795 ssnprintf->len_left -= len; 5796 ssnprintf->len += len; 5797 show->target += len; 5798 } 5799 } 5800 5801 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj, 5802 char *buf, int len, u64 flags) 5803 { 5804 struct btf_show_snprintf ssnprintf; 5805 5806 ssnprintf.show.target = buf; 5807 ssnprintf.show.flags = flags; 5808 ssnprintf.show.showfn = btf_snprintf_show; 5809 ssnprintf.len_left = len; 5810 ssnprintf.len = 0; 5811 5812 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf); 5813 5814 /* If we encontered an error, return it. */ 5815 if (ssnprintf.show.state.status) 5816 return ssnprintf.show.state.status; 5817 5818 /* Otherwise return length we would have written */ 5819 return ssnprintf.len; 5820 } 5821 5822 #ifdef CONFIG_PROC_FS 5823 static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp) 5824 { 5825 const struct btf *btf = filp->private_data; 5826 5827 seq_printf(m, "btf_id:\t%u\n", btf->id); 5828 } 5829 #endif 5830 5831 static int btf_release(struct inode *inode, struct file *filp) 5832 { 5833 btf_put(filp->private_data); 5834 return 0; 5835 } 5836 5837 const struct file_operations btf_fops = { 5838 #ifdef CONFIG_PROC_FS 5839 .show_fdinfo = bpf_btf_show_fdinfo, 5840 #endif 5841 .release = btf_release, 5842 }; 5843 5844 static int __btf_new_fd(struct btf *btf) 5845 { 5846 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC); 5847 } 5848 5849 int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr) 5850 { 5851 struct btf *btf; 5852 int ret; 5853 5854 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel), 5855 attr->btf_size, attr->btf_log_level, 5856 u64_to_user_ptr(attr->btf_log_buf), 5857 attr->btf_log_size); 5858 if (IS_ERR(btf)) 5859 return PTR_ERR(btf); 5860 5861 ret = btf_alloc_id(btf); 5862 if (ret) { 5863 btf_free(btf); 5864 return ret; 5865 } 5866 5867 /* 5868 * The BTF ID is published to the userspace. 5869 * All BTF free must go through call_rcu() from 5870 * now on (i.e. free by calling btf_put()). 5871 */ 5872 5873 ret = __btf_new_fd(btf); 5874 if (ret < 0) 5875 btf_put(btf); 5876 5877 return ret; 5878 } 5879 5880 struct btf *btf_get_by_fd(int fd) 5881 { 5882 struct btf *btf; 5883 struct fd f; 5884 5885 f = fdget(fd); 5886 5887 if (!f.file) 5888 return ERR_PTR(-EBADF); 5889 5890 if (f.file->f_op != &btf_fops) { 5891 fdput(f); 5892 return ERR_PTR(-EINVAL); 5893 } 5894 5895 btf = f.file->private_data; 5896 refcount_inc(&btf->refcnt); 5897 fdput(f); 5898 5899 return btf; 5900 } 5901 5902 int btf_get_info_by_fd(const struct btf *btf, 5903 const union bpf_attr *attr, 5904 union bpf_attr __user *uattr) 5905 { 5906 struct bpf_btf_info __user *uinfo; 5907 struct bpf_btf_info info; 5908 u32 info_copy, btf_copy; 5909 void __user *ubtf; 5910 char __user *uname; 5911 u32 uinfo_len, uname_len, name_len; 5912 int ret = 0; 5913 5914 uinfo = u64_to_user_ptr(attr->info.info); 5915 uinfo_len = attr->info.info_len; 5916 5917 info_copy = min_t(u32, uinfo_len, sizeof(info)); 5918 memset(&info, 0, sizeof(info)); 5919 if (copy_from_user(&info, uinfo, info_copy)) 5920 return -EFAULT; 5921 5922 info.id = btf->id; 5923 ubtf = u64_to_user_ptr(info.btf); 5924 btf_copy = min_t(u32, btf->data_size, info.btf_size); 5925 if (copy_to_user(ubtf, btf->data, btf_copy)) 5926 return -EFAULT; 5927 info.btf_size = btf->data_size; 5928 5929 info.kernel_btf = btf->kernel_btf; 5930 5931 uname = u64_to_user_ptr(info.name); 5932 uname_len = info.name_len; 5933 if (!uname ^ !uname_len) 5934 return -EINVAL; 5935 5936 name_len = strlen(btf->name); 5937 info.name_len = name_len; 5938 5939 if (uname) { 5940 if (uname_len >= name_len + 1) { 5941 if (copy_to_user(uname, btf->name, name_len + 1)) 5942 return -EFAULT; 5943 } else { 5944 char zero = '\0'; 5945 5946 if (copy_to_user(uname, btf->name, uname_len - 1)) 5947 return -EFAULT; 5948 if (put_user(zero, uname + uname_len - 1)) 5949 return -EFAULT; 5950 /* let user-space know about too short buffer */ 5951 ret = -ENOSPC; 5952 } 5953 } 5954 5955 if (copy_to_user(uinfo, &info, info_copy) || 5956 put_user(info_copy, &uattr->info.info_len)) 5957 return -EFAULT; 5958 5959 return ret; 5960 } 5961 5962 int btf_get_fd_by_id(u32 id) 5963 { 5964 struct btf *btf; 5965 int fd; 5966 5967 rcu_read_lock(); 5968 btf = idr_find(&btf_idr, id); 5969 if (!btf || !refcount_inc_not_zero(&btf->refcnt)) 5970 btf = ERR_PTR(-ENOENT); 5971 rcu_read_unlock(); 5972 5973 if (IS_ERR(btf)) 5974 return PTR_ERR(btf); 5975 5976 fd = __btf_new_fd(btf); 5977 if (fd < 0) 5978 btf_put(btf); 5979 5980 return fd; 5981 } 5982 5983 u32 btf_obj_id(const struct btf *btf) 5984 { 5985 return btf->id; 5986 } 5987 5988 bool btf_is_kernel(const struct btf *btf) 5989 { 5990 return btf->kernel_btf; 5991 } 5992 5993 bool btf_is_module(const struct btf *btf) 5994 { 5995 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0; 5996 } 5997 5998 static int btf_id_cmp_func(const void *a, const void *b) 5999 { 6000 const int *pa = a, *pb = b; 6001 6002 return *pa - *pb; 6003 } 6004 6005 bool btf_id_set_contains(const struct btf_id_set *set, u32 id) 6006 { 6007 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL; 6008 } 6009 6010 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES 6011 struct btf_module { 6012 struct list_head list; 6013 struct module *module; 6014 struct btf *btf; 6015 struct bin_attribute *sysfs_attr; 6016 }; 6017 6018 static LIST_HEAD(btf_modules); 6019 static DEFINE_MUTEX(btf_module_mutex); 6020 6021 static ssize_t 6022 btf_module_read(struct file *file, struct kobject *kobj, 6023 struct bin_attribute *bin_attr, 6024 char *buf, loff_t off, size_t len) 6025 { 6026 const struct btf *btf = bin_attr->private; 6027 6028 memcpy(buf, btf->data + off, len); 6029 return len; 6030 } 6031 6032 static int btf_module_notify(struct notifier_block *nb, unsigned long op, 6033 void *module) 6034 { 6035 struct btf_module *btf_mod, *tmp; 6036 struct module *mod = module; 6037 struct btf *btf; 6038 int err = 0; 6039 6040 if (mod->btf_data_size == 0 || 6041 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) 6042 goto out; 6043 6044 switch (op) { 6045 case MODULE_STATE_COMING: 6046 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL); 6047 if (!btf_mod) { 6048 err = -ENOMEM; 6049 goto out; 6050 } 6051 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size); 6052 if (IS_ERR(btf)) { 6053 pr_warn("failed to validate module [%s] BTF: %ld\n", 6054 mod->name, PTR_ERR(btf)); 6055 kfree(btf_mod); 6056 err = PTR_ERR(btf); 6057 goto out; 6058 } 6059 err = btf_alloc_id(btf); 6060 if (err) { 6061 btf_free(btf); 6062 kfree(btf_mod); 6063 goto out; 6064 } 6065 6066 mutex_lock(&btf_module_mutex); 6067 btf_mod->module = module; 6068 btf_mod->btf = btf; 6069 list_add(&btf_mod->list, &btf_modules); 6070 mutex_unlock(&btf_module_mutex); 6071 6072 if (IS_ENABLED(CONFIG_SYSFS)) { 6073 struct bin_attribute *attr; 6074 6075 attr = kzalloc(sizeof(*attr), GFP_KERNEL); 6076 if (!attr) 6077 goto out; 6078 6079 sysfs_bin_attr_init(attr); 6080 attr->attr.name = btf->name; 6081 attr->attr.mode = 0444; 6082 attr->size = btf->data_size; 6083 attr->private = btf; 6084 attr->read = btf_module_read; 6085 6086 err = sysfs_create_bin_file(btf_kobj, attr); 6087 if (err) { 6088 pr_warn("failed to register module [%s] BTF in sysfs: %d\n", 6089 mod->name, err); 6090 kfree(attr); 6091 err = 0; 6092 goto out; 6093 } 6094 6095 btf_mod->sysfs_attr = attr; 6096 } 6097 6098 break; 6099 case MODULE_STATE_GOING: 6100 mutex_lock(&btf_module_mutex); 6101 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) { 6102 if (btf_mod->module != module) 6103 continue; 6104 6105 list_del(&btf_mod->list); 6106 if (btf_mod->sysfs_attr) 6107 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr); 6108 btf_put(btf_mod->btf); 6109 kfree(btf_mod->sysfs_attr); 6110 kfree(btf_mod); 6111 break; 6112 } 6113 mutex_unlock(&btf_module_mutex); 6114 break; 6115 } 6116 out: 6117 return notifier_from_errno(err); 6118 } 6119 6120 static struct notifier_block btf_module_nb = { 6121 .notifier_call = btf_module_notify, 6122 }; 6123 6124 static int __init btf_module_init(void) 6125 { 6126 register_module_notifier(&btf_module_nb); 6127 return 0; 6128 } 6129 6130 fs_initcall(btf_module_init); 6131 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */ 6132 6133 struct module *btf_try_get_module(const struct btf *btf) 6134 { 6135 struct module *res = NULL; 6136 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES 6137 struct btf_module *btf_mod, *tmp; 6138 6139 mutex_lock(&btf_module_mutex); 6140 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) { 6141 if (btf_mod->btf != btf) 6142 continue; 6143 6144 if (try_module_get(btf_mod->module)) 6145 res = btf_mod->module; 6146 6147 break; 6148 } 6149 mutex_unlock(&btf_module_mutex); 6150 #endif 6151 6152 return res; 6153 } 6154 6155 BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags) 6156 { 6157 struct btf *btf; 6158 long ret; 6159 6160 if (flags) 6161 return -EINVAL; 6162 6163 if (name_sz <= 1 || name[name_sz - 1]) 6164 return -EINVAL; 6165 6166 btf = bpf_get_btf_vmlinux(); 6167 if (IS_ERR(btf)) 6168 return PTR_ERR(btf); 6169 6170 ret = btf_find_by_name_kind(btf, name, kind); 6171 /* ret is never zero, since btf_find_by_name_kind returns 6172 * positive btf_id or negative error. 6173 */ 6174 if (ret < 0) { 6175 struct btf *mod_btf; 6176 int id; 6177 6178 /* If name is not found in vmlinux's BTF then search in module's BTFs */ 6179 spin_lock_bh(&btf_idr_lock); 6180 idr_for_each_entry(&btf_idr, mod_btf, id) { 6181 if (!btf_is_module(mod_btf)) 6182 continue; 6183 /* linear search could be slow hence unlock/lock 6184 * the IDR to avoiding holding it for too long 6185 */ 6186 btf_get(mod_btf); 6187 spin_unlock_bh(&btf_idr_lock); 6188 ret = btf_find_by_name_kind(mod_btf, name, kind); 6189 if (ret > 0) { 6190 int btf_obj_fd; 6191 6192 btf_obj_fd = __btf_new_fd(mod_btf); 6193 if (btf_obj_fd < 0) { 6194 btf_put(mod_btf); 6195 return btf_obj_fd; 6196 } 6197 return ret | (((u64)btf_obj_fd) << 32); 6198 } 6199 spin_lock_bh(&btf_idr_lock); 6200 btf_put(mod_btf); 6201 } 6202 spin_unlock_bh(&btf_idr_lock); 6203 } 6204 return ret; 6205 } 6206 6207 const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = { 6208 .func = bpf_btf_find_by_name_kind, 6209 .gpl_only = false, 6210 .ret_type = RET_INTEGER, 6211 .arg1_type = ARG_PTR_TO_MEM, 6212 .arg2_type = ARG_CONST_SIZE, 6213 .arg3_type = ARG_ANYTHING, 6214 .arg4_type = ARG_ANYTHING, 6215 }; 6216