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 desribe 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 0x8f00ffff 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 }; 284 285 static const char *btf_type_str(const struct btf_type *t) 286 { 287 return btf_kind_str[BTF_INFO_KIND(t->info)]; 288 } 289 290 /* Chunk size we use in safe copy of data to be shown. */ 291 #define BTF_SHOW_OBJ_SAFE_SIZE 32 292 293 /* 294 * This is the maximum size of a base type value (equivalent to a 295 * 128-bit int); if we are at the end of our safe buffer and have 296 * less than 16 bytes space we can't be assured of being able 297 * to copy the next type safely, so in such cases we will initiate 298 * a new copy. 299 */ 300 #define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16 301 302 /* Type name size */ 303 #define BTF_SHOW_NAME_SIZE 80 304 305 /* 306 * Common data to all BTF show operations. Private show functions can add 307 * their own data to a structure containing a struct btf_show and consult it 308 * in the show callback. See btf_type_show() below. 309 * 310 * One challenge with showing nested data is we want to skip 0-valued 311 * data, but in order to figure out whether a nested object is all zeros 312 * we need to walk through it. As a result, we need to make two passes 313 * when handling structs, unions and arrays; the first path simply looks 314 * for nonzero data, while the second actually does the display. The first 315 * pass is signalled by show->state.depth_check being set, and if we 316 * encounter a non-zero value we set show->state.depth_to_show to 317 * the depth at which we encountered it. When we have completed the 318 * first pass, we will know if anything needs to be displayed if 319 * depth_to_show > depth. See btf_[struct,array]_show() for the 320 * implementation of this. 321 * 322 * Another problem is we want to ensure the data for display is safe to 323 * access. To support this, the anonymous "struct {} obj" tracks the data 324 * object and our safe copy of it. We copy portions of the data needed 325 * to the object "copy" buffer, but because its size is limited to 326 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we 327 * traverse larger objects for display. 328 * 329 * The various data type show functions all start with a call to 330 * btf_show_start_type() which returns a pointer to the safe copy 331 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the 332 * raw data itself). btf_show_obj_safe() is responsible for 333 * using copy_from_kernel_nofault() to update the safe data if necessary 334 * as we traverse the object's data. skbuff-like semantics are 335 * used: 336 * 337 * - obj.head points to the start of the toplevel object for display 338 * - obj.size is the size of the toplevel object 339 * - obj.data points to the current point in the original data at 340 * which our safe data starts. obj.data will advance as we copy 341 * portions of the data. 342 * 343 * In most cases a single copy will suffice, but larger data structures 344 * such as "struct task_struct" will require many copies. The logic in 345 * btf_show_obj_safe() handles the logic that determines if a new 346 * copy_from_kernel_nofault() is needed. 347 */ 348 struct btf_show { 349 u64 flags; 350 void *target; /* target of show operation (seq file, buffer) */ 351 void (*showfn)(struct btf_show *show, const char *fmt, va_list args); 352 const struct btf *btf; 353 /* below are used during iteration */ 354 struct { 355 u8 depth; 356 u8 depth_to_show; 357 u8 depth_check; 358 u8 array_member:1, 359 array_terminated:1; 360 u16 array_encoding; 361 u32 type_id; 362 int status; /* non-zero for error */ 363 const struct btf_type *type; 364 const struct btf_member *member; 365 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */ 366 } state; 367 struct { 368 u32 size; 369 void *head; 370 void *data; 371 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE]; 372 } obj; 373 }; 374 375 struct btf_kind_operations { 376 s32 (*check_meta)(struct btf_verifier_env *env, 377 const struct btf_type *t, 378 u32 meta_left); 379 int (*resolve)(struct btf_verifier_env *env, 380 const struct resolve_vertex *v); 381 int (*check_member)(struct btf_verifier_env *env, 382 const struct btf_type *struct_type, 383 const struct btf_member *member, 384 const struct btf_type *member_type); 385 int (*check_kflag_member)(struct btf_verifier_env *env, 386 const struct btf_type *struct_type, 387 const struct btf_member *member, 388 const struct btf_type *member_type); 389 void (*log_details)(struct btf_verifier_env *env, 390 const struct btf_type *t); 391 void (*show)(const struct btf *btf, const struct btf_type *t, 392 u32 type_id, void *data, u8 bits_offsets, 393 struct btf_show *show); 394 }; 395 396 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS]; 397 static struct btf_type btf_void; 398 399 static int btf_resolve(struct btf_verifier_env *env, 400 const struct btf_type *t, u32 type_id); 401 402 static bool btf_type_is_modifier(const struct btf_type *t) 403 { 404 /* Some of them is not strictly a C modifier 405 * but they are grouped into the same bucket 406 * for BTF concern: 407 * A type (t) that refers to another 408 * type through t->type AND its size cannot 409 * be determined without following the t->type. 410 * 411 * ptr does not fall into this bucket 412 * because its size is always sizeof(void *). 413 */ 414 switch (BTF_INFO_KIND(t->info)) { 415 case BTF_KIND_TYPEDEF: 416 case BTF_KIND_VOLATILE: 417 case BTF_KIND_CONST: 418 case BTF_KIND_RESTRICT: 419 return true; 420 } 421 422 return false; 423 } 424 425 bool btf_type_is_void(const struct btf_type *t) 426 { 427 return t == &btf_void; 428 } 429 430 static bool btf_type_is_fwd(const struct btf_type *t) 431 { 432 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD; 433 } 434 435 static bool btf_type_nosize(const struct btf_type *t) 436 { 437 return btf_type_is_void(t) || btf_type_is_fwd(t) || 438 btf_type_is_func(t) || btf_type_is_func_proto(t); 439 } 440 441 static bool btf_type_nosize_or_null(const struct btf_type *t) 442 { 443 return !t || btf_type_nosize(t); 444 } 445 446 static bool __btf_type_is_struct(const struct btf_type *t) 447 { 448 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT; 449 } 450 451 static bool btf_type_is_array(const struct btf_type *t) 452 { 453 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY; 454 } 455 456 static bool btf_type_is_datasec(const struct btf_type *t) 457 { 458 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC; 459 } 460 461 u32 btf_nr_types(const struct btf *btf) 462 { 463 u32 total = 0; 464 465 while (btf) { 466 total += btf->nr_types; 467 btf = btf->base_btf; 468 } 469 470 return total; 471 } 472 473 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind) 474 { 475 const struct btf_type *t; 476 const char *tname; 477 u32 i, total; 478 479 total = btf_nr_types(btf); 480 for (i = 1; i < total; i++) { 481 t = btf_type_by_id(btf, i); 482 if (BTF_INFO_KIND(t->info) != kind) 483 continue; 484 485 tname = btf_name_by_offset(btf, t->name_off); 486 if (!strcmp(tname, name)) 487 return i; 488 } 489 490 return -ENOENT; 491 } 492 493 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf, 494 u32 id, u32 *res_id) 495 { 496 const struct btf_type *t = btf_type_by_id(btf, id); 497 498 while (btf_type_is_modifier(t)) { 499 id = t->type; 500 t = btf_type_by_id(btf, t->type); 501 } 502 503 if (res_id) 504 *res_id = id; 505 506 return t; 507 } 508 509 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf, 510 u32 id, u32 *res_id) 511 { 512 const struct btf_type *t; 513 514 t = btf_type_skip_modifiers(btf, id, NULL); 515 if (!btf_type_is_ptr(t)) 516 return NULL; 517 518 return btf_type_skip_modifiers(btf, t->type, res_id); 519 } 520 521 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf, 522 u32 id, u32 *res_id) 523 { 524 const struct btf_type *ptype; 525 526 ptype = btf_type_resolve_ptr(btf, id, res_id); 527 if (ptype && btf_type_is_func_proto(ptype)) 528 return ptype; 529 530 return NULL; 531 } 532 533 /* Types that act only as a source, not sink or intermediate 534 * type when resolving. 535 */ 536 static bool btf_type_is_resolve_source_only(const struct btf_type *t) 537 { 538 return btf_type_is_var(t) || 539 btf_type_is_datasec(t); 540 } 541 542 /* What types need to be resolved? 543 * 544 * btf_type_is_modifier() is an obvious one. 545 * 546 * btf_type_is_struct() because its member refers to 547 * another type (through member->type). 548 * 549 * btf_type_is_var() because the variable refers to 550 * another type. btf_type_is_datasec() holds multiple 551 * btf_type_is_var() types that need resolving. 552 * 553 * btf_type_is_array() because its element (array->type) 554 * refers to another type. Array can be thought of a 555 * special case of struct while array just has the same 556 * member-type repeated by array->nelems of times. 557 */ 558 static bool btf_type_needs_resolve(const struct btf_type *t) 559 { 560 return btf_type_is_modifier(t) || 561 btf_type_is_ptr(t) || 562 btf_type_is_struct(t) || 563 btf_type_is_array(t) || 564 btf_type_is_var(t) || 565 btf_type_is_datasec(t); 566 } 567 568 /* t->size can be used */ 569 static bool btf_type_has_size(const struct btf_type *t) 570 { 571 switch (BTF_INFO_KIND(t->info)) { 572 case BTF_KIND_INT: 573 case BTF_KIND_STRUCT: 574 case BTF_KIND_UNION: 575 case BTF_KIND_ENUM: 576 case BTF_KIND_DATASEC: 577 return true; 578 } 579 580 return false; 581 } 582 583 static const char *btf_int_encoding_str(u8 encoding) 584 { 585 if (encoding == 0) 586 return "(none)"; 587 else if (encoding == BTF_INT_SIGNED) 588 return "SIGNED"; 589 else if (encoding == BTF_INT_CHAR) 590 return "CHAR"; 591 else if (encoding == BTF_INT_BOOL) 592 return "BOOL"; 593 else 594 return "UNKN"; 595 } 596 597 static u32 btf_type_int(const struct btf_type *t) 598 { 599 return *(u32 *)(t + 1); 600 } 601 602 static const struct btf_array *btf_type_array(const struct btf_type *t) 603 { 604 return (const struct btf_array *)(t + 1); 605 } 606 607 static const struct btf_enum *btf_type_enum(const struct btf_type *t) 608 { 609 return (const struct btf_enum *)(t + 1); 610 } 611 612 static const struct btf_var *btf_type_var(const struct btf_type *t) 613 { 614 return (const struct btf_var *)(t + 1); 615 } 616 617 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t) 618 { 619 return kind_ops[BTF_INFO_KIND(t->info)]; 620 } 621 622 static bool btf_name_offset_valid(const struct btf *btf, u32 offset) 623 { 624 if (!BTF_STR_OFFSET_VALID(offset)) 625 return false; 626 627 while (offset < btf->start_str_off) 628 btf = btf->base_btf; 629 630 offset -= btf->start_str_off; 631 return offset < btf->hdr.str_len; 632 } 633 634 static bool __btf_name_char_ok(char c, bool first, bool dot_ok) 635 { 636 if ((first ? !isalpha(c) : 637 !isalnum(c)) && 638 c != '_' && 639 ((c == '.' && !dot_ok) || 640 c != '.')) 641 return false; 642 return true; 643 } 644 645 static const char *btf_str_by_offset(const struct btf *btf, u32 offset) 646 { 647 while (offset < btf->start_str_off) 648 btf = btf->base_btf; 649 650 offset -= btf->start_str_off; 651 if (offset < btf->hdr.str_len) 652 return &btf->strings[offset]; 653 654 return NULL; 655 } 656 657 static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok) 658 { 659 /* offset must be valid */ 660 const char *src = btf_str_by_offset(btf, offset); 661 const char *src_limit; 662 663 if (!__btf_name_char_ok(*src, true, dot_ok)) 664 return false; 665 666 /* set a limit on identifier length */ 667 src_limit = src + KSYM_NAME_LEN; 668 src++; 669 while (*src && src < src_limit) { 670 if (!__btf_name_char_ok(*src, false, dot_ok)) 671 return false; 672 src++; 673 } 674 675 return !*src; 676 } 677 678 /* Only C-style identifier is permitted. This can be relaxed if 679 * necessary. 680 */ 681 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset) 682 { 683 return __btf_name_valid(btf, offset, false); 684 } 685 686 static bool btf_name_valid_section(const struct btf *btf, u32 offset) 687 { 688 return __btf_name_valid(btf, offset, true); 689 } 690 691 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset) 692 { 693 const char *name; 694 695 if (!offset) 696 return "(anon)"; 697 698 name = btf_str_by_offset(btf, offset); 699 return name ?: "(invalid-name-offset)"; 700 } 701 702 const char *btf_name_by_offset(const struct btf *btf, u32 offset) 703 { 704 return btf_str_by_offset(btf, offset); 705 } 706 707 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) 708 { 709 while (type_id < btf->start_id) 710 btf = btf->base_btf; 711 712 type_id -= btf->start_id; 713 if (type_id >= btf->nr_types) 714 return NULL; 715 return btf->types[type_id]; 716 } 717 718 /* 719 * Regular int is not a bit field and it must be either 720 * u8/u16/u32/u64 or __int128. 721 */ 722 static bool btf_type_int_is_regular(const struct btf_type *t) 723 { 724 u8 nr_bits, nr_bytes; 725 u32 int_data; 726 727 int_data = btf_type_int(t); 728 nr_bits = BTF_INT_BITS(int_data); 729 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits); 730 if (BITS_PER_BYTE_MASKED(nr_bits) || 731 BTF_INT_OFFSET(int_data) || 732 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) && 733 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) && 734 nr_bytes != (2 * sizeof(u64)))) { 735 return false; 736 } 737 738 return true; 739 } 740 741 /* 742 * Check that given struct member is a regular int with expected 743 * offset and size. 744 */ 745 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s, 746 const struct btf_member *m, 747 u32 expected_offset, u32 expected_size) 748 { 749 const struct btf_type *t; 750 u32 id, int_data; 751 u8 nr_bits; 752 753 id = m->type; 754 t = btf_type_id_size(btf, &id, NULL); 755 if (!t || !btf_type_is_int(t)) 756 return false; 757 758 int_data = btf_type_int(t); 759 nr_bits = BTF_INT_BITS(int_data); 760 if (btf_type_kflag(s)) { 761 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset); 762 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset); 763 764 /* if kflag set, int should be a regular int and 765 * bit offset should be at byte boundary. 766 */ 767 return !bitfield_size && 768 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset && 769 BITS_ROUNDUP_BYTES(nr_bits) == expected_size; 770 } 771 772 if (BTF_INT_OFFSET(int_data) || 773 BITS_PER_BYTE_MASKED(m->offset) || 774 BITS_ROUNDUP_BYTES(m->offset) != expected_offset || 775 BITS_PER_BYTE_MASKED(nr_bits) || 776 BITS_ROUNDUP_BYTES(nr_bits) != expected_size) 777 return false; 778 779 return true; 780 } 781 782 /* Similar to btf_type_skip_modifiers() but does not skip typedefs. */ 783 static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf, 784 u32 id) 785 { 786 const struct btf_type *t = btf_type_by_id(btf, id); 787 788 while (btf_type_is_modifier(t) && 789 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) { 790 id = t->type; 791 t = btf_type_by_id(btf, t->type); 792 } 793 794 return t; 795 } 796 797 #define BTF_SHOW_MAX_ITER 10 798 799 #define BTF_KIND_BIT(kind) (1ULL << kind) 800 801 /* 802 * Populate show->state.name with type name information. 803 * Format of type name is 804 * 805 * [.member_name = ] (type_name) 806 */ 807 static const char *btf_show_name(struct btf_show *show) 808 { 809 /* BTF_MAX_ITER array suffixes "[]" */ 810 const char *array_suffixes = "[][][][][][][][][][]"; 811 const char *array_suffix = &array_suffixes[strlen(array_suffixes)]; 812 /* BTF_MAX_ITER pointer suffixes "*" */ 813 const char *ptr_suffixes = "**********"; 814 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)]; 815 const char *name = NULL, *prefix = "", *parens = ""; 816 const struct btf_member *m = show->state.member; 817 const struct btf_type *t = show->state.type; 818 const struct btf_array *array; 819 u32 id = show->state.type_id; 820 const char *member = NULL; 821 bool show_member = false; 822 u64 kinds = 0; 823 int i; 824 825 show->state.name[0] = '\0'; 826 827 /* 828 * Don't show type name if we're showing an array member; 829 * in that case we show the array type so don't need to repeat 830 * ourselves for each member. 831 */ 832 if (show->state.array_member) 833 return ""; 834 835 /* Retrieve member name, if any. */ 836 if (m) { 837 member = btf_name_by_offset(show->btf, m->name_off); 838 show_member = strlen(member) > 0; 839 id = m->type; 840 } 841 842 /* 843 * Start with type_id, as we have resolved the struct btf_type * 844 * via btf_modifier_show() past the parent typedef to the child 845 * struct, int etc it is defined as. In such cases, the type_id 846 * still represents the starting type while the struct btf_type * 847 * in our show->state points at the resolved type of the typedef. 848 */ 849 t = btf_type_by_id(show->btf, id); 850 if (!t) 851 return ""; 852 853 /* 854 * The goal here is to build up the right number of pointer and 855 * array suffixes while ensuring the type name for a typedef 856 * is represented. Along the way we accumulate a list of 857 * BTF kinds we have encountered, since these will inform later 858 * display; for example, pointer types will not require an 859 * opening "{" for struct, we will just display the pointer value. 860 * 861 * We also want to accumulate the right number of pointer or array 862 * indices in the format string while iterating until we get to 863 * the typedef/pointee/array member target type. 864 * 865 * We start by pointing at the end of pointer and array suffix 866 * strings; as we accumulate pointers and arrays we move the pointer 867 * or array string backwards so it will show the expected number of 868 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers 869 * and/or arrays and typedefs are supported as a precaution. 870 * 871 * We also want to get typedef name while proceeding to resolve 872 * type it points to so that we can add parentheses if it is a 873 * "typedef struct" etc. 874 */ 875 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) { 876 877 switch (BTF_INFO_KIND(t->info)) { 878 case BTF_KIND_TYPEDEF: 879 if (!name) 880 name = btf_name_by_offset(show->btf, 881 t->name_off); 882 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF); 883 id = t->type; 884 break; 885 case BTF_KIND_ARRAY: 886 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY); 887 parens = "["; 888 if (!t) 889 return ""; 890 array = btf_type_array(t); 891 if (array_suffix > array_suffixes) 892 array_suffix -= 2; 893 id = array->type; 894 break; 895 case BTF_KIND_PTR: 896 kinds |= BTF_KIND_BIT(BTF_KIND_PTR); 897 if (ptr_suffix > ptr_suffixes) 898 ptr_suffix -= 1; 899 id = t->type; 900 break; 901 default: 902 id = 0; 903 break; 904 } 905 if (!id) 906 break; 907 t = btf_type_skip_qualifiers(show->btf, id); 908 } 909 /* We may not be able to represent this type; bail to be safe */ 910 if (i == BTF_SHOW_MAX_ITER) 911 return ""; 912 913 if (!name) 914 name = btf_name_by_offset(show->btf, t->name_off); 915 916 switch (BTF_INFO_KIND(t->info)) { 917 case BTF_KIND_STRUCT: 918 case BTF_KIND_UNION: 919 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ? 920 "struct" : "union"; 921 /* if it's an array of struct/union, parens is already set */ 922 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY)))) 923 parens = "{"; 924 break; 925 case BTF_KIND_ENUM: 926 prefix = "enum"; 927 break; 928 default: 929 break; 930 } 931 932 /* pointer does not require parens */ 933 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR)) 934 parens = ""; 935 /* typedef does not require struct/union/enum prefix */ 936 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF)) 937 prefix = ""; 938 939 if (!name) 940 name = ""; 941 942 /* Even if we don't want type name info, we want parentheses etc */ 943 if (show->flags & BTF_SHOW_NONAME) 944 snprintf(show->state.name, sizeof(show->state.name), "%s", 945 parens); 946 else 947 snprintf(show->state.name, sizeof(show->state.name), 948 "%s%s%s(%s%s%s%s%s%s)%s", 949 /* first 3 strings comprise ".member = " */ 950 show_member ? "." : "", 951 show_member ? member : "", 952 show_member ? " = " : "", 953 /* ...next is our prefix (struct, enum, etc) */ 954 prefix, 955 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "", 956 /* ...this is the type name itself */ 957 name, 958 /* ...suffixed by the appropriate '*', '[]' suffixes */ 959 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix, 960 array_suffix, parens); 961 962 return show->state.name; 963 } 964 965 static const char *__btf_show_indent(struct btf_show *show) 966 { 967 const char *indents = " "; 968 const char *indent = &indents[strlen(indents)]; 969 970 if ((indent - show->state.depth) >= indents) 971 return indent - show->state.depth; 972 return indents; 973 } 974 975 static const char *btf_show_indent(struct btf_show *show) 976 { 977 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show); 978 } 979 980 static const char *btf_show_newline(struct btf_show *show) 981 { 982 return show->flags & BTF_SHOW_COMPACT ? "" : "\n"; 983 } 984 985 static const char *btf_show_delim(struct btf_show *show) 986 { 987 if (show->state.depth == 0) 988 return ""; 989 990 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type && 991 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION) 992 return "|"; 993 994 return ","; 995 } 996 997 __printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...) 998 { 999 va_list args; 1000 1001 if (!show->state.depth_check) { 1002 va_start(args, fmt); 1003 show->showfn(show, fmt, args); 1004 va_end(args); 1005 } 1006 } 1007 1008 /* Macros are used here as btf_show_type_value[s]() prepends and appends 1009 * format specifiers to the format specifier passed in; these do the work of 1010 * adding indentation, delimiters etc while the caller simply has to specify 1011 * the type value(s) in the format specifier + value(s). 1012 */ 1013 #define btf_show_type_value(show, fmt, value) \ 1014 do { \ 1015 if ((value) != 0 || (show->flags & BTF_SHOW_ZERO) || \ 1016 show->state.depth == 0) { \ 1017 btf_show(show, "%s%s" fmt "%s%s", \ 1018 btf_show_indent(show), \ 1019 btf_show_name(show), \ 1020 value, btf_show_delim(show), \ 1021 btf_show_newline(show)); \ 1022 if (show->state.depth > show->state.depth_to_show) \ 1023 show->state.depth_to_show = show->state.depth; \ 1024 } \ 1025 } while (0) 1026 1027 #define btf_show_type_values(show, fmt, ...) \ 1028 do { \ 1029 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \ 1030 btf_show_name(show), \ 1031 __VA_ARGS__, btf_show_delim(show), \ 1032 btf_show_newline(show)); \ 1033 if (show->state.depth > show->state.depth_to_show) \ 1034 show->state.depth_to_show = show->state.depth; \ 1035 } while (0) 1036 1037 /* How much is left to copy to safe buffer after @data? */ 1038 static int btf_show_obj_size_left(struct btf_show *show, void *data) 1039 { 1040 return show->obj.head + show->obj.size - data; 1041 } 1042 1043 /* Is object pointed to by @data of @size already copied to our safe buffer? */ 1044 static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size) 1045 { 1046 return data >= show->obj.data && 1047 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE); 1048 } 1049 1050 /* 1051 * If object pointed to by @data of @size falls within our safe buffer, return 1052 * the equivalent pointer to the same safe data. Assumes 1053 * copy_from_kernel_nofault() has already happened and our safe buffer is 1054 * populated. 1055 */ 1056 static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size) 1057 { 1058 if (btf_show_obj_is_safe(show, data, size)) 1059 return show->obj.safe + (data - show->obj.data); 1060 return NULL; 1061 } 1062 1063 /* 1064 * Return a safe-to-access version of data pointed to by @data. 1065 * We do this by copying the relevant amount of information 1066 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault(). 1067 * 1068 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no 1069 * safe copy is needed. 1070 * 1071 * Otherwise we need to determine if we have the required amount 1072 * of data (determined by the @data pointer and the size of the 1073 * largest base type we can encounter (represented by 1074 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures 1075 * that we will be able to print some of the current object, 1076 * and if more is needed a copy will be triggered. 1077 * Some objects such as structs will not fit into the buffer; 1078 * in such cases additional copies when we iterate over their 1079 * members may be needed. 1080 * 1081 * btf_show_obj_safe() is used to return a safe buffer for 1082 * btf_show_start_type(); this ensures that as we recurse into 1083 * nested types we always have safe data for the given type. 1084 * This approach is somewhat wasteful; it's possible for example 1085 * that when iterating over a large union we'll end up copying the 1086 * same data repeatedly, but the goal is safety not performance. 1087 * We use stack data as opposed to per-CPU buffers because the 1088 * iteration over a type can take some time, and preemption handling 1089 * would greatly complicate use of the safe buffer. 1090 */ 1091 static void *btf_show_obj_safe(struct btf_show *show, 1092 const struct btf_type *t, 1093 void *data) 1094 { 1095 const struct btf_type *rt; 1096 int size_left, size; 1097 void *safe = NULL; 1098 1099 if (show->flags & BTF_SHOW_UNSAFE) 1100 return data; 1101 1102 rt = btf_resolve_size(show->btf, t, &size); 1103 if (IS_ERR(rt)) { 1104 show->state.status = PTR_ERR(rt); 1105 return NULL; 1106 } 1107 1108 /* 1109 * Is this toplevel object? If so, set total object size and 1110 * initialize pointers. Otherwise check if we still fall within 1111 * our safe object data. 1112 */ 1113 if (show->state.depth == 0) { 1114 show->obj.size = size; 1115 show->obj.head = data; 1116 } else { 1117 /* 1118 * If the size of the current object is > our remaining 1119 * safe buffer we _may_ need to do a new copy. However 1120 * consider the case of a nested struct; it's size pushes 1121 * us over the safe buffer limit, but showing any individual 1122 * struct members does not. In such cases, we don't need 1123 * to initiate a fresh copy yet; however we definitely need 1124 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left 1125 * in our buffer, regardless of the current object size. 1126 * The logic here is that as we resolve types we will 1127 * hit a base type at some point, and we need to be sure 1128 * the next chunk of data is safely available to display 1129 * that type info safely. We cannot rely on the size of 1130 * the current object here because it may be much larger 1131 * than our current buffer (e.g. task_struct is 8k). 1132 * All we want to do here is ensure that we can print the 1133 * next basic type, which we can if either 1134 * - the current type size is within the safe buffer; or 1135 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in 1136 * the safe buffer. 1137 */ 1138 safe = __btf_show_obj_safe(show, data, 1139 min(size, 1140 BTF_SHOW_OBJ_BASE_TYPE_SIZE)); 1141 } 1142 1143 /* 1144 * We need a new copy to our safe object, either because we haven't 1145 * yet copied and are intializing safe data, or because the data 1146 * we want falls outside the boundaries of the safe object. 1147 */ 1148 if (!safe) { 1149 size_left = btf_show_obj_size_left(show, data); 1150 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE) 1151 size_left = BTF_SHOW_OBJ_SAFE_SIZE; 1152 show->state.status = copy_from_kernel_nofault(show->obj.safe, 1153 data, size_left); 1154 if (!show->state.status) { 1155 show->obj.data = data; 1156 safe = show->obj.safe; 1157 } 1158 } 1159 1160 return safe; 1161 } 1162 1163 /* 1164 * Set the type we are starting to show and return a safe data pointer 1165 * to be used for showing the associated data. 1166 */ 1167 static void *btf_show_start_type(struct btf_show *show, 1168 const struct btf_type *t, 1169 u32 type_id, void *data) 1170 { 1171 show->state.type = t; 1172 show->state.type_id = type_id; 1173 show->state.name[0] = '\0'; 1174 1175 return btf_show_obj_safe(show, t, data); 1176 } 1177 1178 static void btf_show_end_type(struct btf_show *show) 1179 { 1180 show->state.type = NULL; 1181 show->state.type_id = 0; 1182 show->state.name[0] = '\0'; 1183 } 1184 1185 static void *btf_show_start_aggr_type(struct btf_show *show, 1186 const struct btf_type *t, 1187 u32 type_id, void *data) 1188 { 1189 void *safe_data = btf_show_start_type(show, t, type_id, data); 1190 1191 if (!safe_data) 1192 return safe_data; 1193 1194 btf_show(show, "%s%s%s", btf_show_indent(show), 1195 btf_show_name(show), 1196 btf_show_newline(show)); 1197 show->state.depth++; 1198 return safe_data; 1199 } 1200 1201 static void btf_show_end_aggr_type(struct btf_show *show, 1202 const char *suffix) 1203 { 1204 show->state.depth--; 1205 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix, 1206 btf_show_delim(show), btf_show_newline(show)); 1207 btf_show_end_type(show); 1208 } 1209 1210 static void btf_show_start_member(struct btf_show *show, 1211 const struct btf_member *m) 1212 { 1213 show->state.member = m; 1214 } 1215 1216 static void btf_show_start_array_member(struct btf_show *show) 1217 { 1218 show->state.array_member = 1; 1219 btf_show_start_member(show, NULL); 1220 } 1221 1222 static void btf_show_end_member(struct btf_show *show) 1223 { 1224 show->state.member = NULL; 1225 } 1226 1227 static void btf_show_end_array_member(struct btf_show *show) 1228 { 1229 show->state.array_member = 0; 1230 btf_show_end_member(show); 1231 } 1232 1233 static void *btf_show_start_array_type(struct btf_show *show, 1234 const struct btf_type *t, 1235 u32 type_id, 1236 u16 array_encoding, 1237 void *data) 1238 { 1239 show->state.array_encoding = array_encoding; 1240 show->state.array_terminated = 0; 1241 return btf_show_start_aggr_type(show, t, type_id, data); 1242 } 1243 1244 static void btf_show_end_array_type(struct btf_show *show) 1245 { 1246 show->state.array_encoding = 0; 1247 show->state.array_terminated = 0; 1248 btf_show_end_aggr_type(show, "]"); 1249 } 1250 1251 static void *btf_show_start_struct_type(struct btf_show *show, 1252 const struct btf_type *t, 1253 u32 type_id, 1254 void *data) 1255 { 1256 return btf_show_start_aggr_type(show, t, type_id, data); 1257 } 1258 1259 static void btf_show_end_struct_type(struct btf_show *show) 1260 { 1261 btf_show_end_aggr_type(show, "}"); 1262 } 1263 1264 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log, 1265 const char *fmt, ...) 1266 { 1267 va_list args; 1268 1269 va_start(args, fmt); 1270 bpf_verifier_vlog(log, fmt, args); 1271 va_end(args); 1272 } 1273 1274 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env, 1275 const char *fmt, ...) 1276 { 1277 struct bpf_verifier_log *log = &env->log; 1278 va_list args; 1279 1280 if (!bpf_verifier_log_needed(log)) 1281 return; 1282 1283 va_start(args, fmt); 1284 bpf_verifier_vlog(log, fmt, args); 1285 va_end(args); 1286 } 1287 1288 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env, 1289 const struct btf_type *t, 1290 bool log_details, 1291 const char *fmt, ...) 1292 { 1293 struct bpf_verifier_log *log = &env->log; 1294 u8 kind = BTF_INFO_KIND(t->info); 1295 struct btf *btf = env->btf; 1296 va_list args; 1297 1298 if (!bpf_verifier_log_needed(log)) 1299 return; 1300 1301 /* btf verifier prints all types it is processing via 1302 * btf_verifier_log_type(..., fmt = NULL). 1303 * Skip those prints for in-kernel BTF verification. 1304 */ 1305 if (log->level == BPF_LOG_KERNEL && !fmt) 1306 return; 1307 1308 __btf_verifier_log(log, "[%u] %s %s%s", 1309 env->log_type_id, 1310 btf_kind_str[kind], 1311 __btf_name_by_offset(btf, t->name_off), 1312 log_details ? " " : ""); 1313 1314 if (log_details) 1315 btf_type_ops(t)->log_details(env, t); 1316 1317 if (fmt && *fmt) { 1318 __btf_verifier_log(log, " "); 1319 va_start(args, fmt); 1320 bpf_verifier_vlog(log, fmt, args); 1321 va_end(args); 1322 } 1323 1324 __btf_verifier_log(log, "\n"); 1325 } 1326 1327 #define btf_verifier_log_type(env, t, ...) \ 1328 __btf_verifier_log_type((env), (t), true, __VA_ARGS__) 1329 #define btf_verifier_log_basic(env, t, ...) \ 1330 __btf_verifier_log_type((env), (t), false, __VA_ARGS__) 1331 1332 __printf(4, 5) 1333 static void btf_verifier_log_member(struct btf_verifier_env *env, 1334 const struct btf_type *struct_type, 1335 const struct btf_member *member, 1336 const char *fmt, ...) 1337 { 1338 struct bpf_verifier_log *log = &env->log; 1339 struct btf *btf = env->btf; 1340 va_list args; 1341 1342 if (!bpf_verifier_log_needed(log)) 1343 return; 1344 1345 if (log->level == BPF_LOG_KERNEL && !fmt) 1346 return; 1347 /* The CHECK_META phase already did a btf dump. 1348 * 1349 * If member is logged again, it must hit an error in 1350 * parsing this member. It is useful to print out which 1351 * struct this member belongs to. 1352 */ 1353 if (env->phase != CHECK_META) 1354 btf_verifier_log_type(env, struct_type, NULL); 1355 1356 if (btf_type_kflag(struct_type)) 1357 __btf_verifier_log(log, 1358 "\t%s type_id=%u bitfield_size=%u bits_offset=%u", 1359 __btf_name_by_offset(btf, member->name_off), 1360 member->type, 1361 BTF_MEMBER_BITFIELD_SIZE(member->offset), 1362 BTF_MEMBER_BIT_OFFSET(member->offset)); 1363 else 1364 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u", 1365 __btf_name_by_offset(btf, member->name_off), 1366 member->type, member->offset); 1367 1368 if (fmt && *fmt) { 1369 __btf_verifier_log(log, " "); 1370 va_start(args, fmt); 1371 bpf_verifier_vlog(log, fmt, args); 1372 va_end(args); 1373 } 1374 1375 __btf_verifier_log(log, "\n"); 1376 } 1377 1378 __printf(4, 5) 1379 static void btf_verifier_log_vsi(struct btf_verifier_env *env, 1380 const struct btf_type *datasec_type, 1381 const struct btf_var_secinfo *vsi, 1382 const char *fmt, ...) 1383 { 1384 struct bpf_verifier_log *log = &env->log; 1385 va_list args; 1386 1387 if (!bpf_verifier_log_needed(log)) 1388 return; 1389 if (log->level == BPF_LOG_KERNEL && !fmt) 1390 return; 1391 if (env->phase != CHECK_META) 1392 btf_verifier_log_type(env, datasec_type, NULL); 1393 1394 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u", 1395 vsi->type, vsi->offset, vsi->size); 1396 if (fmt && *fmt) { 1397 __btf_verifier_log(log, " "); 1398 va_start(args, fmt); 1399 bpf_verifier_vlog(log, fmt, args); 1400 va_end(args); 1401 } 1402 1403 __btf_verifier_log(log, "\n"); 1404 } 1405 1406 static void btf_verifier_log_hdr(struct btf_verifier_env *env, 1407 u32 btf_data_size) 1408 { 1409 struct bpf_verifier_log *log = &env->log; 1410 const struct btf *btf = env->btf; 1411 const struct btf_header *hdr; 1412 1413 if (!bpf_verifier_log_needed(log)) 1414 return; 1415 1416 if (log->level == BPF_LOG_KERNEL) 1417 return; 1418 hdr = &btf->hdr; 1419 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic); 1420 __btf_verifier_log(log, "version: %u\n", hdr->version); 1421 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags); 1422 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len); 1423 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off); 1424 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len); 1425 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off); 1426 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len); 1427 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size); 1428 } 1429 1430 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t) 1431 { 1432 struct btf *btf = env->btf; 1433 1434 if (btf->types_size == btf->nr_types) { 1435 /* Expand 'types' array */ 1436 1437 struct btf_type **new_types; 1438 u32 expand_by, new_size; 1439 1440 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) { 1441 btf_verifier_log(env, "Exceeded max num of types"); 1442 return -E2BIG; 1443 } 1444 1445 expand_by = max_t(u32, btf->types_size >> 2, 16); 1446 new_size = min_t(u32, BTF_MAX_TYPE, 1447 btf->types_size + expand_by); 1448 1449 new_types = kvcalloc(new_size, sizeof(*new_types), 1450 GFP_KERNEL | __GFP_NOWARN); 1451 if (!new_types) 1452 return -ENOMEM; 1453 1454 if (btf->nr_types == 0) { 1455 if (!btf->base_btf) { 1456 /* lazily init VOID type */ 1457 new_types[0] = &btf_void; 1458 btf->nr_types++; 1459 } 1460 } else { 1461 memcpy(new_types, btf->types, 1462 sizeof(*btf->types) * btf->nr_types); 1463 } 1464 1465 kvfree(btf->types); 1466 btf->types = new_types; 1467 btf->types_size = new_size; 1468 } 1469 1470 btf->types[btf->nr_types++] = t; 1471 1472 return 0; 1473 } 1474 1475 static int btf_alloc_id(struct btf *btf) 1476 { 1477 int id; 1478 1479 idr_preload(GFP_KERNEL); 1480 spin_lock_bh(&btf_idr_lock); 1481 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC); 1482 if (id > 0) 1483 btf->id = id; 1484 spin_unlock_bh(&btf_idr_lock); 1485 idr_preload_end(); 1486 1487 if (WARN_ON_ONCE(!id)) 1488 return -ENOSPC; 1489 1490 return id > 0 ? 0 : id; 1491 } 1492 1493 static void btf_free_id(struct btf *btf) 1494 { 1495 unsigned long flags; 1496 1497 /* 1498 * In map-in-map, calling map_delete_elem() on outer 1499 * map will call bpf_map_put on the inner map. 1500 * It will then eventually call btf_free_id() 1501 * on the inner map. Some of the map_delete_elem() 1502 * implementation may have irq disabled, so 1503 * we need to use the _irqsave() version instead 1504 * of the _bh() version. 1505 */ 1506 spin_lock_irqsave(&btf_idr_lock, flags); 1507 idr_remove(&btf_idr, btf->id); 1508 spin_unlock_irqrestore(&btf_idr_lock, flags); 1509 } 1510 1511 static void btf_free(struct btf *btf) 1512 { 1513 kvfree(btf->types); 1514 kvfree(btf->resolved_sizes); 1515 kvfree(btf->resolved_ids); 1516 kvfree(btf->data); 1517 kfree(btf); 1518 } 1519 1520 static void btf_free_rcu(struct rcu_head *rcu) 1521 { 1522 struct btf *btf = container_of(rcu, struct btf, rcu); 1523 1524 btf_free(btf); 1525 } 1526 1527 void btf_get(struct btf *btf) 1528 { 1529 refcount_inc(&btf->refcnt); 1530 } 1531 1532 void btf_put(struct btf *btf) 1533 { 1534 if (btf && refcount_dec_and_test(&btf->refcnt)) { 1535 btf_free_id(btf); 1536 call_rcu(&btf->rcu, btf_free_rcu); 1537 } 1538 } 1539 1540 static int env_resolve_init(struct btf_verifier_env *env) 1541 { 1542 struct btf *btf = env->btf; 1543 u32 nr_types = btf->nr_types; 1544 u32 *resolved_sizes = NULL; 1545 u32 *resolved_ids = NULL; 1546 u8 *visit_states = NULL; 1547 1548 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes), 1549 GFP_KERNEL | __GFP_NOWARN); 1550 if (!resolved_sizes) 1551 goto nomem; 1552 1553 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids), 1554 GFP_KERNEL | __GFP_NOWARN); 1555 if (!resolved_ids) 1556 goto nomem; 1557 1558 visit_states = kvcalloc(nr_types, sizeof(*visit_states), 1559 GFP_KERNEL | __GFP_NOWARN); 1560 if (!visit_states) 1561 goto nomem; 1562 1563 btf->resolved_sizes = resolved_sizes; 1564 btf->resolved_ids = resolved_ids; 1565 env->visit_states = visit_states; 1566 1567 return 0; 1568 1569 nomem: 1570 kvfree(resolved_sizes); 1571 kvfree(resolved_ids); 1572 kvfree(visit_states); 1573 return -ENOMEM; 1574 } 1575 1576 static void btf_verifier_env_free(struct btf_verifier_env *env) 1577 { 1578 kvfree(env->visit_states); 1579 kfree(env); 1580 } 1581 1582 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env, 1583 const struct btf_type *next_type) 1584 { 1585 switch (env->resolve_mode) { 1586 case RESOLVE_TBD: 1587 /* int, enum or void is a sink */ 1588 return !btf_type_needs_resolve(next_type); 1589 case RESOLVE_PTR: 1590 /* int, enum, void, struct, array, func or func_proto is a sink 1591 * for ptr 1592 */ 1593 return !btf_type_is_modifier(next_type) && 1594 !btf_type_is_ptr(next_type); 1595 case RESOLVE_STRUCT_OR_ARRAY: 1596 /* int, enum, void, ptr, func or func_proto is a sink 1597 * for struct and array 1598 */ 1599 return !btf_type_is_modifier(next_type) && 1600 !btf_type_is_array(next_type) && 1601 !btf_type_is_struct(next_type); 1602 default: 1603 BUG(); 1604 } 1605 } 1606 1607 static bool env_type_is_resolved(const struct btf_verifier_env *env, 1608 u32 type_id) 1609 { 1610 /* base BTF types should be resolved by now */ 1611 if (type_id < env->btf->start_id) 1612 return true; 1613 1614 return env->visit_states[type_id - env->btf->start_id] == RESOLVED; 1615 } 1616 1617 static int env_stack_push(struct btf_verifier_env *env, 1618 const struct btf_type *t, u32 type_id) 1619 { 1620 const struct btf *btf = env->btf; 1621 struct resolve_vertex *v; 1622 1623 if (env->top_stack == MAX_RESOLVE_DEPTH) 1624 return -E2BIG; 1625 1626 if (type_id < btf->start_id 1627 || env->visit_states[type_id - btf->start_id] != NOT_VISITED) 1628 return -EEXIST; 1629 1630 env->visit_states[type_id - btf->start_id] = VISITED; 1631 1632 v = &env->stack[env->top_stack++]; 1633 v->t = t; 1634 v->type_id = type_id; 1635 v->next_member = 0; 1636 1637 if (env->resolve_mode == RESOLVE_TBD) { 1638 if (btf_type_is_ptr(t)) 1639 env->resolve_mode = RESOLVE_PTR; 1640 else if (btf_type_is_struct(t) || btf_type_is_array(t)) 1641 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY; 1642 } 1643 1644 return 0; 1645 } 1646 1647 static void env_stack_set_next_member(struct btf_verifier_env *env, 1648 u16 next_member) 1649 { 1650 env->stack[env->top_stack - 1].next_member = next_member; 1651 } 1652 1653 static void env_stack_pop_resolved(struct btf_verifier_env *env, 1654 u32 resolved_type_id, 1655 u32 resolved_size) 1656 { 1657 u32 type_id = env->stack[--(env->top_stack)].type_id; 1658 struct btf *btf = env->btf; 1659 1660 type_id -= btf->start_id; /* adjust to local type id */ 1661 btf->resolved_sizes[type_id] = resolved_size; 1662 btf->resolved_ids[type_id] = resolved_type_id; 1663 env->visit_states[type_id] = RESOLVED; 1664 } 1665 1666 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env) 1667 { 1668 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL; 1669 } 1670 1671 /* Resolve the size of a passed-in "type" 1672 * 1673 * type: is an array (e.g. u32 array[x][y]) 1674 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY, 1675 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always 1676 * corresponds to the return type. 1677 * *elem_type: u32 1678 * *elem_id: id of u32 1679 * *total_nelems: (x * y). Hence, individual elem size is 1680 * (*type_size / *total_nelems) 1681 * *type_id: id of type if it's changed within the function, 0 if not 1682 * 1683 * type: is not an array (e.g. const struct X) 1684 * return type: type "struct X" 1685 * *type_size: sizeof(struct X) 1686 * *elem_type: same as return type ("struct X") 1687 * *elem_id: 0 1688 * *total_nelems: 1 1689 * *type_id: id of type if it's changed within the function, 0 if not 1690 */ 1691 static const struct btf_type * 1692 __btf_resolve_size(const struct btf *btf, const struct btf_type *type, 1693 u32 *type_size, const struct btf_type **elem_type, 1694 u32 *elem_id, u32 *total_nelems, u32 *type_id) 1695 { 1696 const struct btf_type *array_type = NULL; 1697 const struct btf_array *array = NULL; 1698 u32 i, size, nelems = 1, id = 0; 1699 1700 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) { 1701 switch (BTF_INFO_KIND(type->info)) { 1702 /* type->size can be used */ 1703 case BTF_KIND_INT: 1704 case BTF_KIND_STRUCT: 1705 case BTF_KIND_UNION: 1706 case BTF_KIND_ENUM: 1707 size = type->size; 1708 goto resolved; 1709 1710 case BTF_KIND_PTR: 1711 size = sizeof(void *); 1712 goto resolved; 1713 1714 /* Modifiers */ 1715 case BTF_KIND_TYPEDEF: 1716 case BTF_KIND_VOLATILE: 1717 case BTF_KIND_CONST: 1718 case BTF_KIND_RESTRICT: 1719 id = type->type; 1720 type = btf_type_by_id(btf, type->type); 1721 break; 1722 1723 case BTF_KIND_ARRAY: 1724 if (!array_type) 1725 array_type = type; 1726 array = btf_type_array(type); 1727 if (nelems && array->nelems > U32_MAX / nelems) 1728 return ERR_PTR(-EINVAL); 1729 nelems *= array->nelems; 1730 type = btf_type_by_id(btf, array->type); 1731 break; 1732 1733 /* type without size */ 1734 default: 1735 return ERR_PTR(-EINVAL); 1736 } 1737 } 1738 1739 return ERR_PTR(-EINVAL); 1740 1741 resolved: 1742 if (nelems && size > U32_MAX / nelems) 1743 return ERR_PTR(-EINVAL); 1744 1745 *type_size = nelems * size; 1746 if (total_nelems) 1747 *total_nelems = nelems; 1748 if (elem_type) 1749 *elem_type = type; 1750 if (elem_id) 1751 *elem_id = array ? array->type : 0; 1752 if (type_id && id) 1753 *type_id = id; 1754 1755 return array_type ? : type; 1756 } 1757 1758 const struct btf_type * 1759 btf_resolve_size(const struct btf *btf, const struct btf_type *type, 1760 u32 *type_size) 1761 { 1762 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL); 1763 } 1764 1765 static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id) 1766 { 1767 while (type_id < btf->start_id) 1768 btf = btf->base_btf; 1769 1770 return btf->resolved_ids[type_id - btf->start_id]; 1771 } 1772 1773 /* The input param "type_id" must point to a needs_resolve type */ 1774 static const struct btf_type *btf_type_id_resolve(const struct btf *btf, 1775 u32 *type_id) 1776 { 1777 *type_id = btf_resolved_type_id(btf, *type_id); 1778 return btf_type_by_id(btf, *type_id); 1779 } 1780 1781 static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id) 1782 { 1783 while (type_id < btf->start_id) 1784 btf = btf->base_btf; 1785 1786 return btf->resolved_sizes[type_id - btf->start_id]; 1787 } 1788 1789 const struct btf_type *btf_type_id_size(const struct btf *btf, 1790 u32 *type_id, u32 *ret_size) 1791 { 1792 const struct btf_type *size_type; 1793 u32 size_type_id = *type_id; 1794 u32 size = 0; 1795 1796 size_type = btf_type_by_id(btf, size_type_id); 1797 if (btf_type_nosize_or_null(size_type)) 1798 return NULL; 1799 1800 if (btf_type_has_size(size_type)) { 1801 size = size_type->size; 1802 } else if (btf_type_is_array(size_type)) { 1803 size = btf_resolved_type_size(btf, size_type_id); 1804 } else if (btf_type_is_ptr(size_type)) { 1805 size = sizeof(void *); 1806 } else { 1807 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) && 1808 !btf_type_is_var(size_type))) 1809 return NULL; 1810 1811 size_type_id = btf_resolved_type_id(btf, size_type_id); 1812 size_type = btf_type_by_id(btf, size_type_id); 1813 if (btf_type_nosize_or_null(size_type)) 1814 return NULL; 1815 else if (btf_type_has_size(size_type)) 1816 size = size_type->size; 1817 else if (btf_type_is_array(size_type)) 1818 size = btf_resolved_type_size(btf, size_type_id); 1819 else if (btf_type_is_ptr(size_type)) 1820 size = sizeof(void *); 1821 else 1822 return NULL; 1823 } 1824 1825 *type_id = size_type_id; 1826 if (ret_size) 1827 *ret_size = size; 1828 1829 return size_type; 1830 } 1831 1832 static int btf_df_check_member(struct btf_verifier_env *env, 1833 const struct btf_type *struct_type, 1834 const struct btf_member *member, 1835 const struct btf_type *member_type) 1836 { 1837 btf_verifier_log_basic(env, struct_type, 1838 "Unsupported check_member"); 1839 return -EINVAL; 1840 } 1841 1842 static int btf_df_check_kflag_member(struct btf_verifier_env *env, 1843 const struct btf_type *struct_type, 1844 const struct btf_member *member, 1845 const struct btf_type *member_type) 1846 { 1847 btf_verifier_log_basic(env, struct_type, 1848 "Unsupported check_kflag_member"); 1849 return -EINVAL; 1850 } 1851 1852 /* Used for ptr, array and struct/union type members. 1853 * int, enum and modifier types have their specific callback functions. 1854 */ 1855 static int btf_generic_check_kflag_member(struct btf_verifier_env *env, 1856 const struct btf_type *struct_type, 1857 const struct btf_member *member, 1858 const struct btf_type *member_type) 1859 { 1860 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) { 1861 btf_verifier_log_member(env, struct_type, member, 1862 "Invalid member bitfield_size"); 1863 return -EINVAL; 1864 } 1865 1866 /* bitfield size is 0, so member->offset represents bit offset only. 1867 * It is safe to call non kflag check_member variants. 1868 */ 1869 return btf_type_ops(member_type)->check_member(env, struct_type, 1870 member, 1871 member_type); 1872 } 1873 1874 static int btf_df_resolve(struct btf_verifier_env *env, 1875 const struct resolve_vertex *v) 1876 { 1877 btf_verifier_log_basic(env, v->t, "Unsupported resolve"); 1878 return -EINVAL; 1879 } 1880 1881 static void btf_df_show(const struct btf *btf, const struct btf_type *t, 1882 u32 type_id, void *data, u8 bits_offsets, 1883 struct btf_show *show) 1884 { 1885 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info)); 1886 } 1887 1888 static int btf_int_check_member(struct btf_verifier_env *env, 1889 const struct btf_type *struct_type, 1890 const struct btf_member *member, 1891 const struct btf_type *member_type) 1892 { 1893 u32 int_data = btf_type_int(member_type); 1894 u32 struct_bits_off = member->offset; 1895 u32 struct_size = struct_type->size; 1896 u32 nr_copy_bits; 1897 u32 bytes_offset; 1898 1899 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) { 1900 btf_verifier_log_member(env, struct_type, member, 1901 "bits_offset exceeds U32_MAX"); 1902 return -EINVAL; 1903 } 1904 1905 struct_bits_off += BTF_INT_OFFSET(int_data); 1906 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 1907 nr_copy_bits = BTF_INT_BITS(int_data) + 1908 BITS_PER_BYTE_MASKED(struct_bits_off); 1909 1910 if (nr_copy_bits > BITS_PER_U128) { 1911 btf_verifier_log_member(env, struct_type, member, 1912 "nr_copy_bits exceeds 128"); 1913 return -EINVAL; 1914 } 1915 1916 if (struct_size < bytes_offset || 1917 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) { 1918 btf_verifier_log_member(env, struct_type, member, 1919 "Member exceeds struct_size"); 1920 return -EINVAL; 1921 } 1922 1923 return 0; 1924 } 1925 1926 static int btf_int_check_kflag_member(struct btf_verifier_env *env, 1927 const struct btf_type *struct_type, 1928 const struct btf_member *member, 1929 const struct btf_type *member_type) 1930 { 1931 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset; 1932 u32 int_data = btf_type_int(member_type); 1933 u32 struct_size = struct_type->size; 1934 u32 nr_copy_bits; 1935 1936 /* a regular int type is required for the kflag int member */ 1937 if (!btf_type_int_is_regular(member_type)) { 1938 btf_verifier_log_member(env, struct_type, member, 1939 "Invalid member base type"); 1940 return -EINVAL; 1941 } 1942 1943 /* check sanity of bitfield size */ 1944 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset); 1945 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset); 1946 nr_int_data_bits = BTF_INT_BITS(int_data); 1947 if (!nr_bits) { 1948 /* Not a bitfield member, member offset must be at byte 1949 * boundary. 1950 */ 1951 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 1952 btf_verifier_log_member(env, struct_type, member, 1953 "Invalid member offset"); 1954 return -EINVAL; 1955 } 1956 1957 nr_bits = nr_int_data_bits; 1958 } else if (nr_bits > nr_int_data_bits) { 1959 btf_verifier_log_member(env, struct_type, member, 1960 "Invalid member bitfield_size"); 1961 return -EINVAL; 1962 } 1963 1964 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 1965 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off); 1966 if (nr_copy_bits > BITS_PER_U128) { 1967 btf_verifier_log_member(env, struct_type, member, 1968 "nr_copy_bits exceeds 128"); 1969 return -EINVAL; 1970 } 1971 1972 if (struct_size < bytes_offset || 1973 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) { 1974 btf_verifier_log_member(env, struct_type, member, 1975 "Member exceeds struct_size"); 1976 return -EINVAL; 1977 } 1978 1979 return 0; 1980 } 1981 1982 static s32 btf_int_check_meta(struct btf_verifier_env *env, 1983 const struct btf_type *t, 1984 u32 meta_left) 1985 { 1986 u32 int_data, nr_bits, meta_needed = sizeof(int_data); 1987 u16 encoding; 1988 1989 if (meta_left < meta_needed) { 1990 btf_verifier_log_basic(env, t, 1991 "meta_left:%u meta_needed:%u", 1992 meta_left, meta_needed); 1993 return -EINVAL; 1994 } 1995 1996 if (btf_type_vlen(t)) { 1997 btf_verifier_log_type(env, t, "vlen != 0"); 1998 return -EINVAL; 1999 } 2000 2001 if (btf_type_kflag(t)) { 2002 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 2003 return -EINVAL; 2004 } 2005 2006 int_data = btf_type_int(t); 2007 if (int_data & ~BTF_INT_MASK) { 2008 btf_verifier_log_basic(env, t, "Invalid int_data:%x", 2009 int_data); 2010 return -EINVAL; 2011 } 2012 2013 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data); 2014 2015 if (nr_bits > BITS_PER_U128) { 2016 btf_verifier_log_type(env, t, "nr_bits exceeds %zu", 2017 BITS_PER_U128); 2018 return -EINVAL; 2019 } 2020 2021 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) { 2022 btf_verifier_log_type(env, t, "nr_bits exceeds type_size"); 2023 return -EINVAL; 2024 } 2025 2026 /* 2027 * Only one of the encoding bits is allowed and it 2028 * should be sufficient for the pretty print purpose (i.e. decoding). 2029 * Multiple bits can be allowed later if it is found 2030 * to be insufficient. 2031 */ 2032 encoding = BTF_INT_ENCODING(int_data); 2033 if (encoding && 2034 encoding != BTF_INT_SIGNED && 2035 encoding != BTF_INT_CHAR && 2036 encoding != BTF_INT_BOOL) { 2037 btf_verifier_log_type(env, t, "Unsupported encoding"); 2038 return -ENOTSUPP; 2039 } 2040 2041 btf_verifier_log_type(env, t, NULL); 2042 2043 return meta_needed; 2044 } 2045 2046 static void btf_int_log(struct btf_verifier_env *env, 2047 const struct btf_type *t) 2048 { 2049 int int_data = btf_type_int(t); 2050 2051 btf_verifier_log(env, 2052 "size=%u bits_offset=%u nr_bits=%u encoding=%s", 2053 t->size, BTF_INT_OFFSET(int_data), 2054 BTF_INT_BITS(int_data), 2055 btf_int_encoding_str(BTF_INT_ENCODING(int_data))); 2056 } 2057 2058 static void btf_int128_print(struct btf_show *show, void *data) 2059 { 2060 /* data points to a __int128 number. 2061 * Suppose 2062 * int128_num = *(__int128 *)data; 2063 * The below formulas shows what upper_num and lower_num represents: 2064 * upper_num = int128_num >> 64; 2065 * lower_num = int128_num & 0xffffffffFFFFFFFFULL; 2066 */ 2067 u64 upper_num, lower_num; 2068 2069 #ifdef __BIG_ENDIAN_BITFIELD 2070 upper_num = *(u64 *)data; 2071 lower_num = *(u64 *)(data + 8); 2072 #else 2073 upper_num = *(u64 *)(data + 8); 2074 lower_num = *(u64 *)data; 2075 #endif 2076 if (upper_num == 0) 2077 btf_show_type_value(show, "0x%llx", lower_num); 2078 else 2079 btf_show_type_values(show, "0x%llx%016llx", upper_num, 2080 lower_num); 2081 } 2082 2083 static void btf_int128_shift(u64 *print_num, u16 left_shift_bits, 2084 u16 right_shift_bits) 2085 { 2086 u64 upper_num, lower_num; 2087 2088 #ifdef __BIG_ENDIAN_BITFIELD 2089 upper_num = print_num[0]; 2090 lower_num = print_num[1]; 2091 #else 2092 upper_num = print_num[1]; 2093 lower_num = print_num[0]; 2094 #endif 2095 2096 /* shake out un-needed bits by shift/or operations */ 2097 if (left_shift_bits >= 64) { 2098 upper_num = lower_num << (left_shift_bits - 64); 2099 lower_num = 0; 2100 } else { 2101 upper_num = (upper_num << left_shift_bits) | 2102 (lower_num >> (64 - left_shift_bits)); 2103 lower_num = lower_num << left_shift_bits; 2104 } 2105 2106 if (right_shift_bits >= 64) { 2107 lower_num = upper_num >> (right_shift_bits - 64); 2108 upper_num = 0; 2109 } else { 2110 lower_num = (lower_num >> right_shift_bits) | 2111 (upper_num << (64 - right_shift_bits)); 2112 upper_num = upper_num >> right_shift_bits; 2113 } 2114 2115 #ifdef __BIG_ENDIAN_BITFIELD 2116 print_num[0] = upper_num; 2117 print_num[1] = lower_num; 2118 #else 2119 print_num[0] = lower_num; 2120 print_num[1] = upper_num; 2121 #endif 2122 } 2123 2124 static void btf_bitfield_show(void *data, u8 bits_offset, 2125 u8 nr_bits, struct btf_show *show) 2126 { 2127 u16 left_shift_bits, right_shift_bits; 2128 u8 nr_copy_bytes; 2129 u8 nr_copy_bits; 2130 u64 print_num[2] = {}; 2131 2132 nr_copy_bits = nr_bits + bits_offset; 2133 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits); 2134 2135 memcpy(print_num, data, nr_copy_bytes); 2136 2137 #ifdef __BIG_ENDIAN_BITFIELD 2138 left_shift_bits = bits_offset; 2139 #else 2140 left_shift_bits = BITS_PER_U128 - nr_copy_bits; 2141 #endif 2142 right_shift_bits = BITS_PER_U128 - nr_bits; 2143 2144 btf_int128_shift(print_num, left_shift_bits, right_shift_bits); 2145 btf_int128_print(show, print_num); 2146 } 2147 2148 2149 static void btf_int_bits_show(const struct btf *btf, 2150 const struct btf_type *t, 2151 void *data, u8 bits_offset, 2152 struct btf_show *show) 2153 { 2154 u32 int_data = btf_type_int(t); 2155 u8 nr_bits = BTF_INT_BITS(int_data); 2156 u8 total_bits_offset; 2157 2158 /* 2159 * bits_offset is at most 7. 2160 * BTF_INT_OFFSET() cannot exceed 128 bits. 2161 */ 2162 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data); 2163 data += BITS_ROUNDDOWN_BYTES(total_bits_offset); 2164 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset); 2165 btf_bitfield_show(data, bits_offset, nr_bits, show); 2166 } 2167 2168 static void btf_int_show(const struct btf *btf, const struct btf_type *t, 2169 u32 type_id, void *data, u8 bits_offset, 2170 struct btf_show *show) 2171 { 2172 u32 int_data = btf_type_int(t); 2173 u8 encoding = BTF_INT_ENCODING(int_data); 2174 bool sign = encoding & BTF_INT_SIGNED; 2175 u8 nr_bits = BTF_INT_BITS(int_data); 2176 void *safe_data; 2177 2178 safe_data = btf_show_start_type(show, t, type_id, data); 2179 if (!safe_data) 2180 return; 2181 2182 if (bits_offset || BTF_INT_OFFSET(int_data) || 2183 BITS_PER_BYTE_MASKED(nr_bits)) { 2184 btf_int_bits_show(btf, t, safe_data, bits_offset, show); 2185 goto out; 2186 } 2187 2188 switch (nr_bits) { 2189 case 128: 2190 btf_int128_print(show, safe_data); 2191 break; 2192 case 64: 2193 if (sign) 2194 btf_show_type_value(show, "%lld", *(s64 *)safe_data); 2195 else 2196 btf_show_type_value(show, "%llu", *(u64 *)safe_data); 2197 break; 2198 case 32: 2199 if (sign) 2200 btf_show_type_value(show, "%d", *(s32 *)safe_data); 2201 else 2202 btf_show_type_value(show, "%u", *(u32 *)safe_data); 2203 break; 2204 case 16: 2205 if (sign) 2206 btf_show_type_value(show, "%d", *(s16 *)safe_data); 2207 else 2208 btf_show_type_value(show, "%u", *(u16 *)safe_data); 2209 break; 2210 case 8: 2211 if (show->state.array_encoding == BTF_INT_CHAR) { 2212 /* check for null terminator */ 2213 if (show->state.array_terminated) 2214 break; 2215 if (*(char *)data == '\0') { 2216 show->state.array_terminated = 1; 2217 break; 2218 } 2219 if (isprint(*(char *)data)) { 2220 btf_show_type_value(show, "'%c'", 2221 *(char *)safe_data); 2222 break; 2223 } 2224 } 2225 if (sign) 2226 btf_show_type_value(show, "%d", *(s8 *)safe_data); 2227 else 2228 btf_show_type_value(show, "%u", *(u8 *)safe_data); 2229 break; 2230 default: 2231 btf_int_bits_show(btf, t, safe_data, bits_offset, show); 2232 break; 2233 } 2234 out: 2235 btf_show_end_type(show); 2236 } 2237 2238 static const struct btf_kind_operations int_ops = { 2239 .check_meta = btf_int_check_meta, 2240 .resolve = btf_df_resolve, 2241 .check_member = btf_int_check_member, 2242 .check_kflag_member = btf_int_check_kflag_member, 2243 .log_details = btf_int_log, 2244 .show = btf_int_show, 2245 }; 2246 2247 static int btf_modifier_check_member(struct btf_verifier_env *env, 2248 const struct btf_type *struct_type, 2249 const struct btf_member *member, 2250 const struct btf_type *member_type) 2251 { 2252 const struct btf_type *resolved_type; 2253 u32 resolved_type_id = member->type; 2254 struct btf_member resolved_member; 2255 struct btf *btf = env->btf; 2256 2257 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL); 2258 if (!resolved_type) { 2259 btf_verifier_log_member(env, struct_type, member, 2260 "Invalid member"); 2261 return -EINVAL; 2262 } 2263 2264 resolved_member = *member; 2265 resolved_member.type = resolved_type_id; 2266 2267 return btf_type_ops(resolved_type)->check_member(env, struct_type, 2268 &resolved_member, 2269 resolved_type); 2270 } 2271 2272 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env, 2273 const struct btf_type *struct_type, 2274 const struct btf_member *member, 2275 const struct btf_type *member_type) 2276 { 2277 const struct btf_type *resolved_type; 2278 u32 resolved_type_id = member->type; 2279 struct btf_member resolved_member; 2280 struct btf *btf = env->btf; 2281 2282 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL); 2283 if (!resolved_type) { 2284 btf_verifier_log_member(env, struct_type, member, 2285 "Invalid member"); 2286 return -EINVAL; 2287 } 2288 2289 resolved_member = *member; 2290 resolved_member.type = resolved_type_id; 2291 2292 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type, 2293 &resolved_member, 2294 resolved_type); 2295 } 2296 2297 static int btf_ptr_check_member(struct btf_verifier_env *env, 2298 const struct btf_type *struct_type, 2299 const struct btf_member *member, 2300 const struct btf_type *member_type) 2301 { 2302 u32 struct_size, struct_bits_off, bytes_offset; 2303 2304 struct_size = struct_type->size; 2305 struct_bits_off = member->offset; 2306 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 2307 2308 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 2309 btf_verifier_log_member(env, struct_type, member, 2310 "Member is not byte aligned"); 2311 return -EINVAL; 2312 } 2313 2314 if (struct_size - bytes_offset < sizeof(void *)) { 2315 btf_verifier_log_member(env, struct_type, member, 2316 "Member exceeds struct_size"); 2317 return -EINVAL; 2318 } 2319 2320 return 0; 2321 } 2322 2323 static int btf_ref_type_check_meta(struct btf_verifier_env *env, 2324 const struct btf_type *t, 2325 u32 meta_left) 2326 { 2327 if (btf_type_vlen(t)) { 2328 btf_verifier_log_type(env, t, "vlen != 0"); 2329 return -EINVAL; 2330 } 2331 2332 if (btf_type_kflag(t)) { 2333 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 2334 return -EINVAL; 2335 } 2336 2337 if (!BTF_TYPE_ID_VALID(t->type)) { 2338 btf_verifier_log_type(env, t, "Invalid type_id"); 2339 return -EINVAL; 2340 } 2341 2342 /* typedef type must have a valid name, and other ref types, 2343 * volatile, const, restrict, should have a null name. 2344 */ 2345 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) { 2346 if (!t->name_off || 2347 !btf_name_valid_identifier(env->btf, t->name_off)) { 2348 btf_verifier_log_type(env, t, "Invalid name"); 2349 return -EINVAL; 2350 } 2351 } else { 2352 if (t->name_off) { 2353 btf_verifier_log_type(env, t, "Invalid name"); 2354 return -EINVAL; 2355 } 2356 } 2357 2358 btf_verifier_log_type(env, t, NULL); 2359 2360 return 0; 2361 } 2362 2363 static int btf_modifier_resolve(struct btf_verifier_env *env, 2364 const struct resolve_vertex *v) 2365 { 2366 const struct btf_type *t = v->t; 2367 const struct btf_type *next_type; 2368 u32 next_type_id = t->type; 2369 struct btf *btf = env->btf; 2370 2371 next_type = btf_type_by_id(btf, next_type_id); 2372 if (!next_type || btf_type_is_resolve_source_only(next_type)) { 2373 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2374 return -EINVAL; 2375 } 2376 2377 if (!env_type_is_resolve_sink(env, next_type) && 2378 !env_type_is_resolved(env, next_type_id)) 2379 return env_stack_push(env, next_type, next_type_id); 2380 2381 /* Figure out the resolved next_type_id with size. 2382 * They will be stored in the current modifier's 2383 * resolved_ids and resolved_sizes such that it can 2384 * save us a few type-following when we use it later (e.g. in 2385 * pretty print). 2386 */ 2387 if (!btf_type_id_size(btf, &next_type_id, NULL)) { 2388 if (env_type_is_resolved(env, next_type_id)) 2389 next_type = btf_type_id_resolve(btf, &next_type_id); 2390 2391 /* "typedef void new_void", "const void"...etc */ 2392 if (!btf_type_is_void(next_type) && 2393 !btf_type_is_fwd(next_type) && 2394 !btf_type_is_func_proto(next_type)) { 2395 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2396 return -EINVAL; 2397 } 2398 } 2399 2400 env_stack_pop_resolved(env, next_type_id, 0); 2401 2402 return 0; 2403 } 2404 2405 static int btf_var_resolve(struct btf_verifier_env *env, 2406 const struct resolve_vertex *v) 2407 { 2408 const struct btf_type *next_type; 2409 const struct btf_type *t = v->t; 2410 u32 next_type_id = t->type; 2411 struct btf *btf = env->btf; 2412 2413 next_type = btf_type_by_id(btf, next_type_id); 2414 if (!next_type || btf_type_is_resolve_source_only(next_type)) { 2415 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2416 return -EINVAL; 2417 } 2418 2419 if (!env_type_is_resolve_sink(env, next_type) && 2420 !env_type_is_resolved(env, next_type_id)) 2421 return env_stack_push(env, next_type, next_type_id); 2422 2423 if (btf_type_is_modifier(next_type)) { 2424 const struct btf_type *resolved_type; 2425 u32 resolved_type_id; 2426 2427 resolved_type_id = next_type_id; 2428 resolved_type = btf_type_id_resolve(btf, &resolved_type_id); 2429 2430 if (btf_type_is_ptr(resolved_type) && 2431 !env_type_is_resolve_sink(env, resolved_type) && 2432 !env_type_is_resolved(env, resolved_type_id)) 2433 return env_stack_push(env, resolved_type, 2434 resolved_type_id); 2435 } 2436 2437 /* We must resolve to something concrete at this point, no 2438 * forward types or similar that would resolve to size of 2439 * zero is allowed. 2440 */ 2441 if (!btf_type_id_size(btf, &next_type_id, NULL)) { 2442 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2443 return -EINVAL; 2444 } 2445 2446 env_stack_pop_resolved(env, next_type_id, 0); 2447 2448 return 0; 2449 } 2450 2451 static int btf_ptr_resolve(struct btf_verifier_env *env, 2452 const struct resolve_vertex *v) 2453 { 2454 const struct btf_type *next_type; 2455 const struct btf_type *t = v->t; 2456 u32 next_type_id = t->type; 2457 struct btf *btf = env->btf; 2458 2459 next_type = btf_type_by_id(btf, next_type_id); 2460 if (!next_type || btf_type_is_resolve_source_only(next_type)) { 2461 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2462 return -EINVAL; 2463 } 2464 2465 if (!env_type_is_resolve_sink(env, next_type) && 2466 !env_type_is_resolved(env, next_type_id)) 2467 return env_stack_push(env, next_type, next_type_id); 2468 2469 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY, 2470 * the modifier may have stopped resolving when it was resolved 2471 * to a ptr (last-resolved-ptr). 2472 * 2473 * We now need to continue from the last-resolved-ptr to 2474 * ensure the last-resolved-ptr will not referring back to 2475 * the currenct ptr (t). 2476 */ 2477 if (btf_type_is_modifier(next_type)) { 2478 const struct btf_type *resolved_type; 2479 u32 resolved_type_id; 2480 2481 resolved_type_id = next_type_id; 2482 resolved_type = btf_type_id_resolve(btf, &resolved_type_id); 2483 2484 if (btf_type_is_ptr(resolved_type) && 2485 !env_type_is_resolve_sink(env, resolved_type) && 2486 !env_type_is_resolved(env, resolved_type_id)) 2487 return env_stack_push(env, resolved_type, 2488 resolved_type_id); 2489 } 2490 2491 if (!btf_type_id_size(btf, &next_type_id, NULL)) { 2492 if (env_type_is_resolved(env, next_type_id)) 2493 next_type = btf_type_id_resolve(btf, &next_type_id); 2494 2495 if (!btf_type_is_void(next_type) && 2496 !btf_type_is_fwd(next_type) && 2497 !btf_type_is_func_proto(next_type)) { 2498 btf_verifier_log_type(env, v->t, "Invalid type_id"); 2499 return -EINVAL; 2500 } 2501 } 2502 2503 env_stack_pop_resolved(env, next_type_id, 0); 2504 2505 return 0; 2506 } 2507 2508 static void btf_modifier_show(const struct btf *btf, 2509 const struct btf_type *t, 2510 u32 type_id, void *data, 2511 u8 bits_offset, struct btf_show *show) 2512 { 2513 if (btf->resolved_ids) 2514 t = btf_type_id_resolve(btf, &type_id); 2515 else 2516 t = btf_type_skip_modifiers(btf, type_id, NULL); 2517 2518 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show); 2519 } 2520 2521 static void btf_var_show(const struct btf *btf, const struct btf_type *t, 2522 u32 type_id, void *data, u8 bits_offset, 2523 struct btf_show *show) 2524 { 2525 t = btf_type_id_resolve(btf, &type_id); 2526 2527 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show); 2528 } 2529 2530 static void btf_ptr_show(const struct btf *btf, const struct btf_type *t, 2531 u32 type_id, void *data, u8 bits_offset, 2532 struct btf_show *show) 2533 { 2534 void *safe_data; 2535 2536 safe_data = btf_show_start_type(show, t, type_id, data); 2537 if (!safe_data) 2538 return; 2539 2540 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */ 2541 if (show->flags & BTF_SHOW_PTR_RAW) 2542 btf_show_type_value(show, "0x%px", *(void **)safe_data); 2543 else 2544 btf_show_type_value(show, "0x%p", *(void **)safe_data); 2545 btf_show_end_type(show); 2546 } 2547 2548 static void btf_ref_type_log(struct btf_verifier_env *env, 2549 const struct btf_type *t) 2550 { 2551 btf_verifier_log(env, "type_id=%u", t->type); 2552 } 2553 2554 static struct btf_kind_operations modifier_ops = { 2555 .check_meta = btf_ref_type_check_meta, 2556 .resolve = btf_modifier_resolve, 2557 .check_member = btf_modifier_check_member, 2558 .check_kflag_member = btf_modifier_check_kflag_member, 2559 .log_details = btf_ref_type_log, 2560 .show = btf_modifier_show, 2561 }; 2562 2563 static struct btf_kind_operations ptr_ops = { 2564 .check_meta = btf_ref_type_check_meta, 2565 .resolve = btf_ptr_resolve, 2566 .check_member = btf_ptr_check_member, 2567 .check_kflag_member = btf_generic_check_kflag_member, 2568 .log_details = btf_ref_type_log, 2569 .show = btf_ptr_show, 2570 }; 2571 2572 static s32 btf_fwd_check_meta(struct btf_verifier_env *env, 2573 const struct btf_type *t, 2574 u32 meta_left) 2575 { 2576 if (btf_type_vlen(t)) { 2577 btf_verifier_log_type(env, t, "vlen != 0"); 2578 return -EINVAL; 2579 } 2580 2581 if (t->type) { 2582 btf_verifier_log_type(env, t, "type != 0"); 2583 return -EINVAL; 2584 } 2585 2586 /* fwd type must have a valid name */ 2587 if (!t->name_off || 2588 !btf_name_valid_identifier(env->btf, t->name_off)) { 2589 btf_verifier_log_type(env, t, "Invalid name"); 2590 return -EINVAL; 2591 } 2592 2593 btf_verifier_log_type(env, t, NULL); 2594 2595 return 0; 2596 } 2597 2598 static void btf_fwd_type_log(struct btf_verifier_env *env, 2599 const struct btf_type *t) 2600 { 2601 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct"); 2602 } 2603 2604 static struct btf_kind_operations fwd_ops = { 2605 .check_meta = btf_fwd_check_meta, 2606 .resolve = btf_df_resolve, 2607 .check_member = btf_df_check_member, 2608 .check_kflag_member = btf_df_check_kflag_member, 2609 .log_details = btf_fwd_type_log, 2610 .show = btf_df_show, 2611 }; 2612 2613 static int btf_array_check_member(struct btf_verifier_env *env, 2614 const struct btf_type *struct_type, 2615 const struct btf_member *member, 2616 const struct btf_type *member_type) 2617 { 2618 u32 struct_bits_off = member->offset; 2619 u32 struct_size, bytes_offset; 2620 u32 array_type_id, array_size; 2621 struct btf *btf = env->btf; 2622 2623 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 2624 btf_verifier_log_member(env, struct_type, member, 2625 "Member is not byte aligned"); 2626 return -EINVAL; 2627 } 2628 2629 array_type_id = member->type; 2630 btf_type_id_size(btf, &array_type_id, &array_size); 2631 struct_size = struct_type->size; 2632 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 2633 if (struct_size - bytes_offset < array_size) { 2634 btf_verifier_log_member(env, struct_type, member, 2635 "Member exceeds struct_size"); 2636 return -EINVAL; 2637 } 2638 2639 return 0; 2640 } 2641 2642 static s32 btf_array_check_meta(struct btf_verifier_env *env, 2643 const struct btf_type *t, 2644 u32 meta_left) 2645 { 2646 const struct btf_array *array = btf_type_array(t); 2647 u32 meta_needed = sizeof(*array); 2648 2649 if (meta_left < meta_needed) { 2650 btf_verifier_log_basic(env, t, 2651 "meta_left:%u meta_needed:%u", 2652 meta_left, meta_needed); 2653 return -EINVAL; 2654 } 2655 2656 /* array type should not have a name */ 2657 if (t->name_off) { 2658 btf_verifier_log_type(env, t, "Invalid name"); 2659 return -EINVAL; 2660 } 2661 2662 if (btf_type_vlen(t)) { 2663 btf_verifier_log_type(env, t, "vlen != 0"); 2664 return -EINVAL; 2665 } 2666 2667 if (btf_type_kflag(t)) { 2668 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 2669 return -EINVAL; 2670 } 2671 2672 if (t->size) { 2673 btf_verifier_log_type(env, t, "size != 0"); 2674 return -EINVAL; 2675 } 2676 2677 /* Array elem type and index type cannot be in type void, 2678 * so !array->type and !array->index_type are not allowed. 2679 */ 2680 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) { 2681 btf_verifier_log_type(env, t, "Invalid elem"); 2682 return -EINVAL; 2683 } 2684 2685 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) { 2686 btf_verifier_log_type(env, t, "Invalid index"); 2687 return -EINVAL; 2688 } 2689 2690 btf_verifier_log_type(env, t, NULL); 2691 2692 return meta_needed; 2693 } 2694 2695 static int btf_array_resolve(struct btf_verifier_env *env, 2696 const struct resolve_vertex *v) 2697 { 2698 const struct btf_array *array = btf_type_array(v->t); 2699 const struct btf_type *elem_type, *index_type; 2700 u32 elem_type_id, index_type_id; 2701 struct btf *btf = env->btf; 2702 u32 elem_size; 2703 2704 /* Check array->index_type */ 2705 index_type_id = array->index_type; 2706 index_type = btf_type_by_id(btf, index_type_id); 2707 if (btf_type_nosize_or_null(index_type) || 2708 btf_type_is_resolve_source_only(index_type)) { 2709 btf_verifier_log_type(env, v->t, "Invalid index"); 2710 return -EINVAL; 2711 } 2712 2713 if (!env_type_is_resolve_sink(env, index_type) && 2714 !env_type_is_resolved(env, index_type_id)) 2715 return env_stack_push(env, index_type, index_type_id); 2716 2717 index_type = btf_type_id_size(btf, &index_type_id, NULL); 2718 if (!index_type || !btf_type_is_int(index_type) || 2719 !btf_type_int_is_regular(index_type)) { 2720 btf_verifier_log_type(env, v->t, "Invalid index"); 2721 return -EINVAL; 2722 } 2723 2724 /* Check array->type */ 2725 elem_type_id = array->type; 2726 elem_type = btf_type_by_id(btf, elem_type_id); 2727 if (btf_type_nosize_or_null(elem_type) || 2728 btf_type_is_resolve_source_only(elem_type)) { 2729 btf_verifier_log_type(env, v->t, 2730 "Invalid elem"); 2731 return -EINVAL; 2732 } 2733 2734 if (!env_type_is_resolve_sink(env, elem_type) && 2735 !env_type_is_resolved(env, elem_type_id)) 2736 return env_stack_push(env, elem_type, elem_type_id); 2737 2738 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); 2739 if (!elem_type) { 2740 btf_verifier_log_type(env, v->t, "Invalid elem"); 2741 return -EINVAL; 2742 } 2743 2744 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) { 2745 btf_verifier_log_type(env, v->t, "Invalid array of int"); 2746 return -EINVAL; 2747 } 2748 2749 if (array->nelems && elem_size > U32_MAX / array->nelems) { 2750 btf_verifier_log_type(env, v->t, 2751 "Array size overflows U32_MAX"); 2752 return -EINVAL; 2753 } 2754 2755 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems); 2756 2757 return 0; 2758 } 2759 2760 static void btf_array_log(struct btf_verifier_env *env, 2761 const struct btf_type *t) 2762 { 2763 const struct btf_array *array = btf_type_array(t); 2764 2765 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u", 2766 array->type, array->index_type, array->nelems); 2767 } 2768 2769 static void __btf_array_show(const struct btf *btf, const struct btf_type *t, 2770 u32 type_id, void *data, u8 bits_offset, 2771 struct btf_show *show) 2772 { 2773 const struct btf_array *array = btf_type_array(t); 2774 const struct btf_kind_operations *elem_ops; 2775 const struct btf_type *elem_type; 2776 u32 i, elem_size = 0, elem_type_id; 2777 u16 encoding = 0; 2778 2779 elem_type_id = array->type; 2780 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL); 2781 if (elem_type && btf_type_has_size(elem_type)) 2782 elem_size = elem_type->size; 2783 2784 if (elem_type && btf_type_is_int(elem_type)) { 2785 u32 int_type = btf_type_int(elem_type); 2786 2787 encoding = BTF_INT_ENCODING(int_type); 2788 2789 /* 2790 * BTF_INT_CHAR encoding never seems to be set for 2791 * char arrays, so if size is 1 and element is 2792 * printable as a char, we'll do that. 2793 */ 2794 if (elem_size == 1) 2795 encoding = BTF_INT_CHAR; 2796 } 2797 2798 if (!btf_show_start_array_type(show, t, type_id, encoding, data)) 2799 return; 2800 2801 if (!elem_type) 2802 goto out; 2803 elem_ops = btf_type_ops(elem_type); 2804 2805 for (i = 0; i < array->nelems; i++) { 2806 2807 btf_show_start_array_member(show); 2808 2809 elem_ops->show(btf, elem_type, elem_type_id, data, 2810 bits_offset, show); 2811 data += elem_size; 2812 2813 btf_show_end_array_member(show); 2814 2815 if (show->state.array_terminated) 2816 break; 2817 } 2818 out: 2819 btf_show_end_array_type(show); 2820 } 2821 2822 static void btf_array_show(const struct btf *btf, const struct btf_type *t, 2823 u32 type_id, void *data, u8 bits_offset, 2824 struct btf_show *show) 2825 { 2826 const struct btf_member *m = show->state.member; 2827 2828 /* 2829 * First check if any members would be shown (are non-zero). 2830 * See comments above "struct btf_show" definition for more 2831 * details on how this works at a high-level. 2832 */ 2833 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) { 2834 if (!show->state.depth_check) { 2835 show->state.depth_check = show->state.depth + 1; 2836 show->state.depth_to_show = 0; 2837 } 2838 __btf_array_show(btf, t, type_id, data, bits_offset, show); 2839 show->state.member = m; 2840 2841 if (show->state.depth_check != show->state.depth + 1) 2842 return; 2843 show->state.depth_check = 0; 2844 2845 if (show->state.depth_to_show <= show->state.depth) 2846 return; 2847 /* 2848 * Reaching here indicates we have recursed and found 2849 * non-zero array member(s). 2850 */ 2851 } 2852 __btf_array_show(btf, t, type_id, data, bits_offset, show); 2853 } 2854 2855 static struct btf_kind_operations array_ops = { 2856 .check_meta = btf_array_check_meta, 2857 .resolve = btf_array_resolve, 2858 .check_member = btf_array_check_member, 2859 .check_kflag_member = btf_generic_check_kflag_member, 2860 .log_details = btf_array_log, 2861 .show = btf_array_show, 2862 }; 2863 2864 static int btf_struct_check_member(struct btf_verifier_env *env, 2865 const struct btf_type *struct_type, 2866 const struct btf_member *member, 2867 const struct btf_type *member_type) 2868 { 2869 u32 struct_bits_off = member->offset; 2870 u32 struct_size, bytes_offset; 2871 2872 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 2873 btf_verifier_log_member(env, struct_type, member, 2874 "Member is not byte aligned"); 2875 return -EINVAL; 2876 } 2877 2878 struct_size = struct_type->size; 2879 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 2880 if (struct_size - bytes_offset < member_type->size) { 2881 btf_verifier_log_member(env, struct_type, member, 2882 "Member exceeds struct_size"); 2883 return -EINVAL; 2884 } 2885 2886 return 0; 2887 } 2888 2889 static s32 btf_struct_check_meta(struct btf_verifier_env *env, 2890 const struct btf_type *t, 2891 u32 meta_left) 2892 { 2893 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION; 2894 const struct btf_member *member; 2895 u32 meta_needed, last_offset; 2896 struct btf *btf = env->btf; 2897 u32 struct_size = t->size; 2898 u32 offset; 2899 u16 i; 2900 2901 meta_needed = btf_type_vlen(t) * sizeof(*member); 2902 if (meta_left < meta_needed) { 2903 btf_verifier_log_basic(env, t, 2904 "meta_left:%u meta_needed:%u", 2905 meta_left, meta_needed); 2906 return -EINVAL; 2907 } 2908 2909 /* struct type either no name or a valid one */ 2910 if (t->name_off && 2911 !btf_name_valid_identifier(env->btf, t->name_off)) { 2912 btf_verifier_log_type(env, t, "Invalid name"); 2913 return -EINVAL; 2914 } 2915 2916 btf_verifier_log_type(env, t, NULL); 2917 2918 last_offset = 0; 2919 for_each_member(i, t, member) { 2920 if (!btf_name_offset_valid(btf, member->name_off)) { 2921 btf_verifier_log_member(env, t, member, 2922 "Invalid member name_offset:%u", 2923 member->name_off); 2924 return -EINVAL; 2925 } 2926 2927 /* struct member either no name or a valid one */ 2928 if (member->name_off && 2929 !btf_name_valid_identifier(btf, member->name_off)) { 2930 btf_verifier_log_member(env, t, member, "Invalid name"); 2931 return -EINVAL; 2932 } 2933 /* A member cannot be in type void */ 2934 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) { 2935 btf_verifier_log_member(env, t, member, 2936 "Invalid type_id"); 2937 return -EINVAL; 2938 } 2939 2940 offset = btf_member_bit_offset(t, member); 2941 if (is_union && offset) { 2942 btf_verifier_log_member(env, t, member, 2943 "Invalid member bits_offset"); 2944 return -EINVAL; 2945 } 2946 2947 /* 2948 * ">" instead of ">=" because the last member could be 2949 * "char a[0];" 2950 */ 2951 if (last_offset > offset) { 2952 btf_verifier_log_member(env, t, member, 2953 "Invalid member bits_offset"); 2954 return -EINVAL; 2955 } 2956 2957 if (BITS_ROUNDUP_BYTES(offset) > struct_size) { 2958 btf_verifier_log_member(env, t, member, 2959 "Member bits_offset exceeds its struct size"); 2960 return -EINVAL; 2961 } 2962 2963 btf_verifier_log_member(env, t, member, NULL); 2964 last_offset = offset; 2965 } 2966 2967 return meta_needed; 2968 } 2969 2970 static int btf_struct_resolve(struct btf_verifier_env *env, 2971 const struct resolve_vertex *v) 2972 { 2973 const struct btf_member *member; 2974 int err; 2975 u16 i; 2976 2977 /* Before continue resolving the next_member, 2978 * ensure the last member is indeed resolved to a 2979 * type with size info. 2980 */ 2981 if (v->next_member) { 2982 const struct btf_type *last_member_type; 2983 const struct btf_member *last_member; 2984 u16 last_member_type_id; 2985 2986 last_member = btf_type_member(v->t) + v->next_member - 1; 2987 last_member_type_id = last_member->type; 2988 if (WARN_ON_ONCE(!env_type_is_resolved(env, 2989 last_member_type_id))) 2990 return -EINVAL; 2991 2992 last_member_type = btf_type_by_id(env->btf, 2993 last_member_type_id); 2994 if (btf_type_kflag(v->t)) 2995 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t, 2996 last_member, 2997 last_member_type); 2998 else 2999 err = btf_type_ops(last_member_type)->check_member(env, v->t, 3000 last_member, 3001 last_member_type); 3002 if (err) 3003 return err; 3004 } 3005 3006 for_each_member_from(i, v->next_member, v->t, member) { 3007 u32 member_type_id = member->type; 3008 const struct btf_type *member_type = btf_type_by_id(env->btf, 3009 member_type_id); 3010 3011 if (btf_type_nosize_or_null(member_type) || 3012 btf_type_is_resolve_source_only(member_type)) { 3013 btf_verifier_log_member(env, v->t, member, 3014 "Invalid member"); 3015 return -EINVAL; 3016 } 3017 3018 if (!env_type_is_resolve_sink(env, member_type) && 3019 !env_type_is_resolved(env, member_type_id)) { 3020 env_stack_set_next_member(env, i + 1); 3021 return env_stack_push(env, member_type, member_type_id); 3022 } 3023 3024 if (btf_type_kflag(v->t)) 3025 err = btf_type_ops(member_type)->check_kflag_member(env, v->t, 3026 member, 3027 member_type); 3028 else 3029 err = btf_type_ops(member_type)->check_member(env, v->t, 3030 member, 3031 member_type); 3032 if (err) 3033 return err; 3034 } 3035 3036 env_stack_pop_resolved(env, 0, 0); 3037 3038 return 0; 3039 } 3040 3041 static void btf_struct_log(struct btf_verifier_env *env, 3042 const struct btf_type *t) 3043 { 3044 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); 3045 } 3046 3047 /* find 'struct bpf_spin_lock' in map value. 3048 * return >= 0 offset if found 3049 * and < 0 in case of error 3050 */ 3051 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t) 3052 { 3053 const struct btf_member *member; 3054 u32 i, off = -ENOENT; 3055 3056 if (!__btf_type_is_struct(t)) 3057 return -EINVAL; 3058 3059 for_each_member(i, t, member) { 3060 const struct btf_type *member_type = btf_type_by_id(btf, 3061 member->type); 3062 if (!__btf_type_is_struct(member_type)) 3063 continue; 3064 if (member_type->size != sizeof(struct bpf_spin_lock)) 3065 continue; 3066 if (strcmp(__btf_name_by_offset(btf, member_type->name_off), 3067 "bpf_spin_lock")) 3068 continue; 3069 if (off != -ENOENT) 3070 /* only one 'struct bpf_spin_lock' is allowed */ 3071 return -E2BIG; 3072 off = btf_member_bit_offset(t, member); 3073 if (off % 8) 3074 /* valid C code cannot generate such BTF */ 3075 return -EINVAL; 3076 off /= 8; 3077 if (off % __alignof__(struct bpf_spin_lock)) 3078 /* valid struct bpf_spin_lock will be 4 byte aligned */ 3079 return -EINVAL; 3080 } 3081 return off; 3082 } 3083 3084 static void __btf_struct_show(const struct btf *btf, const struct btf_type *t, 3085 u32 type_id, void *data, u8 bits_offset, 3086 struct btf_show *show) 3087 { 3088 const struct btf_member *member; 3089 void *safe_data; 3090 u32 i; 3091 3092 safe_data = btf_show_start_struct_type(show, t, type_id, data); 3093 if (!safe_data) 3094 return; 3095 3096 for_each_member(i, t, member) { 3097 const struct btf_type *member_type = btf_type_by_id(btf, 3098 member->type); 3099 const struct btf_kind_operations *ops; 3100 u32 member_offset, bitfield_size; 3101 u32 bytes_offset; 3102 u8 bits8_offset; 3103 3104 btf_show_start_member(show, member); 3105 3106 member_offset = btf_member_bit_offset(t, member); 3107 bitfield_size = btf_member_bitfield_size(t, member); 3108 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset); 3109 bits8_offset = BITS_PER_BYTE_MASKED(member_offset); 3110 if (bitfield_size) { 3111 safe_data = btf_show_start_type(show, member_type, 3112 member->type, 3113 data + bytes_offset); 3114 if (safe_data) 3115 btf_bitfield_show(safe_data, 3116 bits8_offset, 3117 bitfield_size, show); 3118 btf_show_end_type(show); 3119 } else { 3120 ops = btf_type_ops(member_type); 3121 ops->show(btf, member_type, member->type, 3122 data + bytes_offset, bits8_offset, show); 3123 } 3124 3125 btf_show_end_member(show); 3126 } 3127 3128 btf_show_end_struct_type(show); 3129 } 3130 3131 static void btf_struct_show(const struct btf *btf, const struct btf_type *t, 3132 u32 type_id, void *data, u8 bits_offset, 3133 struct btf_show *show) 3134 { 3135 const struct btf_member *m = show->state.member; 3136 3137 /* 3138 * First check if any members would be shown (are non-zero). 3139 * See comments above "struct btf_show" definition for more 3140 * details on how this works at a high-level. 3141 */ 3142 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) { 3143 if (!show->state.depth_check) { 3144 show->state.depth_check = show->state.depth + 1; 3145 show->state.depth_to_show = 0; 3146 } 3147 __btf_struct_show(btf, t, type_id, data, bits_offset, show); 3148 /* Restore saved member data here */ 3149 show->state.member = m; 3150 if (show->state.depth_check != show->state.depth + 1) 3151 return; 3152 show->state.depth_check = 0; 3153 3154 if (show->state.depth_to_show <= show->state.depth) 3155 return; 3156 /* 3157 * Reaching here indicates we have recursed and found 3158 * non-zero child values. 3159 */ 3160 } 3161 3162 __btf_struct_show(btf, t, type_id, data, bits_offset, show); 3163 } 3164 3165 static struct btf_kind_operations struct_ops = { 3166 .check_meta = btf_struct_check_meta, 3167 .resolve = btf_struct_resolve, 3168 .check_member = btf_struct_check_member, 3169 .check_kflag_member = btf_generic_check_kflag_member, 3170 .log_details = btf_struct_log, 3171 .show = btf_struct_show, 3172 }; 3173 3174 static int btf_enum_check_member(struct btf_verifier_env *env, 3175 const struct btf_type *struct_type, 3176 const struct btf_member *member, 3177 const struct btf_type *member_type) 3178 { 3179 u32 struct_bits_off = member->offset; 3180 u32 struct_size, bytes_offset; 3181 3182 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 3183 btf_verifier_log_member(env, struct_type, member, 3184 "Member is not byte aligned"); 3185 return -EINVAL; 3186 } 3187 3188 struct_size = struct_type->size; 3189 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); 3190 if (struct_size - bytes_offset < member_type->size) { 3191 btf_verifier_log_member(env, struct_type, member, 3192 "Member exceeds struct_size"); 3193 return -EINVAL; 3194 } 3195 3196 return 0; 3197 } 3198 3199 static int btf_enum_check_kflag_member(struct btf_verifier_env *env, 3200 const struct btf_type *struct_type, 3201 const struct btf_member *member, 3202 const struct btf_type *member_type) 3203 { 3204 u32 struct_bits_off, nr_bits, bytes_end, struct_size; 3205 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE; 3206 3207 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset); 3208 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset); 3209 if (!nr_bits) { 3210 if (BITS_PER_BYTE_MASKED(struct_bits_off)) { 3211 btf_verifier_log_member(env, struct_type, member, 3212 "Member is not byte aligned"); 3213 return -EINVAL; 3214 } 3215 3216 nr_bits = int_bitsize; 3217 } else if (nr_bits > int_bitsize) { 3218 btf_verifier_log_member(env, struct_type, member, 3219 "Invalid member bitfield_size"); 3220 return -EINVAL; 3221 } 3222 3223 struct_size = struct_type->size; 3224 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits); 3225 if (struct_size < bytes_end) { 3226 btf_verifier_log_member(env, struct_type, member, 3227 "Member exceeds struct_size"); 3228 return -EINVAL; 3229 } 3230 3231 return 0; 3232 } 3233 3234 static s32 btf_enum_check_meta(struct btf_verifier_env *env, 3235 const struct btf_type *t, 3236 u32 meta_left) 3237 { 3238 const struct btf_enum *enums = btf_type_enum(t); 3239 struct btf *btf = env->btf; 3240 u16 i, nr_enums; 3241 u32 meta_needed; 3242 3243 nr_enums = btf_type_vlen(t); 3244 meta_needed = nr_enums * sizeof(*enums); 3245 3246 if (meta_left < meta_needed) { 3247 btf_verifier_log_basic(env, t, 3248 "meta_left:%u meta_needed:%u", 3249 meta_left, meta_needed); 3250 return -EINVAL; 3251 } 3252 3253 if (btf_type_kflag(t)) { 3254 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3255 return -EINVAL; 3256 } 3257 3258 if (t->size > 8 || !is_power_of_2(t->size)) { 3259 btf_verifier_log_type(env, t, "Unexpected size"); 3260 return -EINVAL; 3261 } 3262 3263 /* enum type either no name or a valid one */ 3264 if (t->name_off && 3265 !btf_name_valid_identifier(env->btf, t->name_off)) { 3266 btf_verifier_log_type(env, t, "Invalid name"); 3267 return -EINVAL; 3268 } 3269 3270 btf_verifier_log_type(env, t, NULL); 3271 3272 for (i = 0; i < nr_enums; i++) { 3273 if (!btf_name_offset_valid(btf, enums[i].name_off)) { 3274 btf_verifier_log(env, "\tInvalid name_offset:%u", 3275 enums[i].name_off); 3276 return -EINVAL; 3277 } 3278 3279 /* enum member must have a valid name */ 3280 if (!enums[i].name_off || 3281 !btf_name_valid_identifier(btf, enums[i].name_off)) { 3282 btf_verifier_log_type(env, t, "Invalid name"); 3283 return -EINVAL; 3284 } 3285 3286 if (env->log.level == BPF_LOG_KERNEL) 3287 continue; 3288 btf_verifier_log(env, "\t%s val=%d\n", 3289 __btf_name_by_offset(btf, enums[i].name_off), 3290 enums[i].val); 3291 } 3292 3293 return meta_needed; 3294 } 3295 3296 static void btf_enum_log(struct btf_verifier_env *env, 3297 const struct btf_type *t) 3298 { 3299 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); 3300 } 3301 3302 static void btf_enum_show(const struct btf *btf, const struct btf_type *t, 3303 u32 type_id, void *data, u8 bits_offset, 3304 struct btf_show *show) 3305 { 3306 const struct btf_enum *enums = btf_type_enum(t); 3307 u32 i, nr_enums = btf_type_vlen(t); 3308 void *safe_data; 3309 int v; 3310 3311 safe_data = btf_show_start_type(show, t, type_id, data); 3312 if (!safe_data) 3313 return; 3314 3315 v = *(int *)safe_data; 3316 3317 for (i = 0; i < nr_enums; i++) { 3318 if (v != enums[i].val) 3319 continue; 3320 3321 btf_show_type_value(show, "%s", 3322 __btf_name_by_offset(btf, 3323 enums[i].name_off)); 3324 3325 btf_show_end_type(show); 3326 return; 3327 } 3328 3329 btf_show_type_value(show, "%d", v); 3330 btf_show_end_type(show); 3331 } 3332 3333 static struct btf_kind_operations enum_ops = { 3334 .check_meta = btf_enum_check_meta, 3335 .resolve = btf_df_resolve, 3336 .check_member = btf_enum_check_member, 3337 .check_kflag_member = btf_enum_check_kflag_member, 3338 .log_details = btf_enum_log, 3339 .show = btf_enum_show, 3340 }; 3341 3342 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env, 3343 const struct btf_type *t, 3344 u32 meta_left) 3345 { 3346 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param); 3347 3348 if (meta_left < meta_needed) { 3349 btf_verifier_log_basic(env, t, 3350 "meta_left:%u meta_needed:%u", 3351 meta_left, meta_needed); 3352 return -EINVAL; 3353 } 3354 3355 if (t->name_off) { 3356 btf_verifier_log_type(env, t, "Invalid name"); 3357 return -EINVAL; 3358 } 3359 3360 if (btf_type_kflag(t)) { 3361 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3362 return -EINVAL; 3363 } 3364 3365 btf_verifier_log_type(env, t, NULL); 3366 3367 return meta_needed; 3368 } 3369 3370 static void btf_func_proto_log(struct btf_verifier_env *env, 3371 const struct btf_type *t) 3372 { 3373 const struct btf_param *args = (const struct btf_param *)(t + 1); 3374 u16 nr_args = btf_type_vlen(t), i; 3375 3376 btf_verifier_log(env, "return=%u args=(", t->type); 3377 if (!nr_args) { 3378 btf_verifier_log(env, "void"); 3379 goto done; 3380 } 3381 3382 if (nr_args == 1 && !args[0].type) { 3383 /* Only one vararg */ 3384 btf_verifier_log(env, "vararg"); 3385 goto done; 3386 } 3387 3388 btf_verifier_log(env, "%u %s", args[0].type, 3389 __btf_name_by_offset(env->btf, 3390 args[0].name_off)); 3391 for (i = 1; i < nr_args - 1; i++) 3392 btf_verifier_log(env, ", %u %s", args[i].type, 3393 __btf_name_by_offset(env->btf, 3394 args[i].name_off)); 3395 3396 if (nr_args > 1) { 3397 const struct btf_param *last_arg = &args[nr_args - 1]; 3398 3399 if (last_arg->type) 3400 btf_verifier_log(env, ", %u %s", last_arg->type, 3401 __btf_name_by_offset(env->btf, 3402 last_arg->name_off)); 3403 else 3404 btf_verifier_log(env, ", vararg"); 3405 } 3406 3407 done: 3408 btf_verifier_log(env, ")"); 3409 } 3410 3411 static struct btf_kind_operations func_proto_ops = { 3412 .check_meta = btf_func_proto_check_meta, 3413 .resolve = btf_df_resolve, 3414 /* 3415 * BTF_KIND_FUNC_PROTO cannot be directly referred by 3416 * a struct's member. 3417 * 3418 * It should be a funciton pointer instead. 3419 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO) 3420 * 3421 * Hence, there is no btf_func_check_member(). 3422 */ 3423 .check_member = btf_df_check_member, 3424 .check_kflag_member = btf_df_check_kflag_member, 3425 .log_details = btf_func_proto_log, 3426 .show = btf_df_show, 3427 }; 3428 3429 static s32 btf_func_check_meta(struct btf_verifier_env *env, 3430 const struct btf_type *t, 3431 u32 meta_left) 3432 { 3433 if (!t->name_off || 3434 !btf_name_valid_identifier(env->btf, t->name_off)) { 3435 btf_verifier_log_type(env, t, "Invalid name"); 3436 return -EINVAL; 3437 } 3438 3439 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) { 3440 btf_verifier_log_type(env, t, "Invalid func linkage"); 3441 return -EINVAL; 3442 } 3443 3444 if (btf_type_kflag(t)) { 3445 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3446 return -EINVAL; 3447 } 3448 3449 btf_verifier_log_type(env, t, NULL); 3450 3451 return 0; 3452 } 3453 3454 static struct btf_kind_operations func_ops = { 3455 .check_meta = btf_func_check_meta, 3456 .resolve = btf_df_resolve, 3457 .check_member = btf_df_check_member, 3458 .check_kflag_member = btf_df_check_kflag_member, 3459 .log_details = btf_ref_type_log, 3460 .show = btf_df_show, 3461 }; 3462 3463 static s32 btf_var_check_meta(struct btf_verifier_env *env, 3464 const struct btf_type *t, 3465 u32 meta_left) 3466 { 3467 const struct btf_var *var; 3468 u32 meta_needed = sizeof(*var); 3469 3470 if (meta_left < meta_needed) { 3471 btf_verifier_log_basic(env, t, 3472 "meta_left:%u meta_needed:%u", 3473 meta_left, meta_needed); 3474 return -EINVAL; 3475 } 3476 3477 if (btf_type_vlen(t)) { 3478 btf_verifier_log_type(env, t, "vlen != 0"); 3479 return -EINVAL; 3480 } 3481 3482 if (btf_type_kflag(t)) { 3483 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3484 return -EINVAL; 3485 } 3486 3487 if (!t->name_off || 3488 !__btf_name_valid(env->btf, t->name_off, true)) { 3489 btf_verifier_log_type(env, t, "Invalid name"); 3490 return -EINVAL; 3491 } 3492 3493 /* A var cannot be in type void */ 3494 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) { 3495 btf_verifier_log_type(env, t, "Invalid type_id"); 3496 return -EINVAL; 3497 } 3498 3499 var = btf_type_var(t); 3500 if (var->linkage != BTF_VAR_STATIC && 3501 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) { 3502 btf_verifier_log_type(env, t, "Linkage not supported"); 3503 return -EINVAL; 3504 } 3505 3506 btf_verifier_log_type(env, t, NULL); 3507 3508 return meta_needed; 3509 } 3510 3511 static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t) 3512 { 3513 const struct btf_var *var = btf_type_var(t); 3514 3515 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage); 3516 } 3517 3518 static const struct btf_kind_operations var_ops = { 3519 .check_meta = btf_var_check_meta, 3520 .resolve = btf_var_resolve, 3521 .check_member = btf_df_check_member, 3522 .check_kflag_member = btf_df_check_kflag_member, 3523 .log_details = btf_var_log, 3524 .show = btf_var_show, 3525 }; 3526 3527 static s32 btf_datasec_check_meta(struct btf_verifier_env *env, 3528 const struct btf_type *t, 3529 u32 meta_left) 3530 { 3531 const struct btf_var_secinfo *vsi; 3532 u64 last_vsi_end_off = 0, sum = 0; 3533 u32 i, meta_needed; 3534 3535 meta_needed = btf_type_vlen(t) * sizeof(*vsi); 3536 if (meta_left < meta_needed) { 3537 btf_verifier_log_basic(env, t, 3538 "meta_left:%u meta_needed:%u", 3539 meta_left, meta_needed); 3540 return -EINVAL; 3541 } 3542 3543 if (!t->size) { 3544 btf_verifier_log_type(env, t, "size == 0"); 3545 return -EINVAL; 3546 } 3547 3548 if (btf_type_kflag(t)) { 3549 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); 3550 return -EINVAL; 3551 } 3552 3553 if (!t->name_off || 3554 !btf_name_valid_section(env->btf, t->name_off)) { 3555 btf_verifier_log_type(env, t, "Invalid name"); 3556 return -EINVAL; 3557 } 3558 3559 btf_verifier_log_type(env, t, NULL); 3560 3561 for_each_vsi(i, t, vsi) { 3562 /* A var cannot be in type void */ 3563 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) { 3564 btf_verifier_log_vsi(env, t, vsi, 3565 "Invalid type_id"); 3566 return -EINVAL; 3567 } 3568 3569 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) { 3570 btf_verifier_log_vsi(env, t, vsi, 3571 "Invalid offset"); 3572 return -EINVAL; 3573 } 3574 3575 if (!vsi->size || vsi->size > t->size) { 3576 btf_verifier_log_vsi(env, t, vsi, 3577 "Invalid size"); 3578 return -EINVAL; 3579 } 3580 3581 last_vsi_end_off = vsi->offset + vsi->size; 3582 if (last_vsi_end_off > t->size) { 3583 btf_verifier_log_vsi(env, t, vsi, 3584 "Invalid offset+size"); 3585 return -EINVAL; 3586 } 3587 3588 btf_verifier_log_vsi(env, t, vsi, NULL); 3589 sum += vsi->size; 3590 } 3591 3592 if (t->size < sum) { 3593 btf_verifier_log_type(env, t, "Invalid btf_info size"); 3594 return -EINVAL; 3595 } 3596 3597 return meta_needed; 3598 } 3599 3600 static int btf_datasec_resolve(struct btf_verifier_env *env, 3601 const struct resolve_vertex *v) 3602 { 3603 const struct btf_var_secinfo *vsi; 3604 struct btf *btf = env->btf; 3605 u16 i; 3606 3607 for_each_vsi_from(i, v->next_member, v->t, vsi) { 3608 u32 var_type_id = vsi->type, type_id, type_size = 0; 3609 const struct btf_type *var_type = btf_type_by_id(env->btf, 3610 var_type_id); 3611 if (!var_type || !btf_type_is_var(var_type)) { 3612 btf_verifier_log_vsi(env, v->t, vsi, 3613 "Not a VAR kind member"); 3614 return -EINVAL; 3615 } 3616 3617 if (!env_type_is_resolve_sink(env, var_type) && 3618 !env_type_is_resolved(env, var_type_id)) { 3619 env_stack_set_next_member(env, i + 1); 3620 return env_stack_push(env, var_type, var_type_id); 3621 } 3622 3623 type_id = var_type->type; 3624 if (!btf_type_id_size(btf, &type_id, &type_size)) { 3625 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type"); 3626 return -EINVAL; 3627 } 3628 3629 if (vsi->size < type_size) { 3630 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size"); 3631 return -EINVAL; 3632 } 3633 } 3634 3635 env_stack_pop_resolved(env, 0, 0); 3636 return 0; 3637 } 3638 3639 static void btf_datasec_log(struct btf_verifier_env *env, 3640 const struct btf_type *t) 3641 { 3642 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); 3643 } 3644 3645 static void btf_datasec_show(const struct btf *btf, 3646 const struct btf_type *t, u32 type_id, 3647 void *data, u8 bits_offset, 3648 struct btf_show *show) 3649 { 3650 const struct btf_var_secinfo *vsi; 3651 const struct btf_type *var; 3652 u32 i; 3653 3654 if (!btf_show_start_type(show, t, type_id, data)) 3655 return; 3656 3657 btf_show_type_value(show, "section (\"%s\") = {", 3658 __btf_name_by_offset(btf, t->name_off)); 3659 for_each_vsi(i, t, vsi) { 3660 var = btf_type_by_id(btf, vsi->type); 3661 if (i) 3662 btf_show(show, ","); 3663 btf_type_ops(var)->show(btf, var, vsi->type, 3664 data + vsi->offset, bits_offset, show); 3665 } 3666 btf_show_end_type(show); 3667 } 3668 3669 static const struct btf_kind_operations datasec_ops = { 3670 .check_meta = btf_datasec_check_meta, 3671 .resolve = btf_datasec_resolve, 3672 .check_member = btf_df_check_member, 3673 .check_kflag_member = btf_df_check_kflag_member, 3674 .log_details = btf_datasec_log, 3675 .show = btf_datasec_show, 3676 }; 3677 3678 static int btf_func_proto_check(struct btf_verifier_env *env, 3679 const struct btf_type *t) 3680 { 3681 const struct btf_type *ret_type; 3682 const struct btf_param *args; 3683 const struct btf *btf; 3684 u16 nr_args, i; 3685 int err; 3686 3687 btf = env->btf; 3688 args = (const struct btf_param *)(t + 1); 3689 nr_args = btf_type_vlen(t); 3690 3691 /* Check func return type which could be "void" (t->type == 0) */ 3692 if (t->type) { 3693 u32 ret_type_id = t->type; 3694 3695 ret_type = btf_type_by_id(btf, ret_type_id); 3696 if (!ret_type) { 3697 btf_verifier_log_type(env, t, "Invalid return type"); 3698 return -EINVAL; 3699 } 3700 3701 if (btf_type_needs_resolve(ret_type) && 3702 !env_type_is_resolved(env, ret_type_id)) { 3703 err = btf_resolve(env, ret_type, ret_type_id); 3704 if (err) 3705 return err; 3706 } 3707 3708 /* Ensure the return type is a type that has a size */ 3709 if (!btf_type_id_size(btf, &ret_type_id, NULL)) { 3710 btf_verifier_log_type(env, t, "Invalid return type"); 3711 return -EINVAL; 3712 } 3713 } 3714 3715 if (!nr_args) 3716 return 0; 3717 3718 /* Last func arg type_id could be 0 if it is a vararg */ 3719 if (!args[nr_args - 1].type) { 3720 if (args[nr_args - 1].name_off) { 3721 btf_verifier_log_type(env, t, "Invalid arg#%u", 3722 nr_args); 3723 return -EINVAL; 3724 } 3725 nr_args--; 3726 } 3727 3728 err = 0; 3729 for (i = 0; i < nr_args; i++) { 3730 const struct btf_type *arg_type; 3731 u32 arg_type_id; 3732 3733 arg_type_id = args[i].type; 3734 arg_type = btf_type_by_id(btf, arg_type_id); 3735 if (!arg_type) { 3736 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); 3737 err = -EINVAL; 3738 break; 3739 } 3740 3741 if (args[i].name_off && 3742 (!btf_name_offset_valid(btf, args[i].name_off) || 3743 !btf_name_valid_identifier(btf, args[i].name_off))) { 3744 btf_verifier_log_type(env, t, 3745 "Invalid arg#%u", i + 1); 3746 err = -EINVAL; 3747 break; 3748 } 3749 3750 if (btf_type_needs_resolve(arg_type) && 3751 !env_type_is_resolved(env, arg_type_id)) { 3752 err = btf_resolve(env, arg_type, arg_type_id); 3753 if (err) 3754 break; 3755 } 3756 3757 if (!btf_type_id_size(btf, &arg_type_id, NULL)) { 3758 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); 3759 err = -EINVAL; 3760 break; 3761 } 3762 } 3763 3764 return err; 3765 } 3766 3767 static int btf_func_check(struct btf_verifier_env *env, 3768 const struct btf_type *t) 3769 { 3770 const struct btf_type *proto_type; 3771 const struct btf_param *args; 3772 const struct btf *btf; 3773 u16 nr_args, i; 3774 3775 btf = env->btf; 3776 proto_type = btf_type_by_id(btf, t->type); 3777 3778 if (!proto_type || !btf_type_is_func_proto(proto_type)) { 3779 btf_verifier_log_type(env, t, "Invalid type_id"); 3780 return -EINVAL; 3781 } 3782 3783 args = (const struct btf_param *)(proto_type + 1); 3784 nr_args = btf_type_vlen(proto_type); 3785 for (i = 0; i < nr_args; i++) { 3786 if (!args[i].name_off && args[i].type) { 3787 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); 3788 return -EINVAL; 3789 } 3790 } 3791 3792 return 0; 3793 } 3794 3795 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = { 3796 [BTF_KIND_INT] = &int_ops, 3797 [BTF_KIND_PTR] = &ptr_ops, 3798 [BTF_KIND_ARRAY] = &array_ops, 3799 [BTF_KIND_STRUCT] = &struct_ops, 3800 [BTF_KIND_UNION] = &struct_ops, 3801 [BTF_KIND_ENUM] = &enum_ops, 3802 [BTF_KIND_FWD] = &fwd_ops, 3803 [BTF_KIND_TYPEDEF] = &modifier_ops, 3804 [BTF_KIND_VOLATILE] = &modifier_ops, 3805 [BTF_KIND_CONST] = &modifier_ops, 3806 [BTF_KIND_RESTRICT] = &modifier_ops, 3807 [BTF_KIND_FUNC] = &func_ops, 3808 [BTF_KIND_FUNC_PROTO] = &func_proto_ops, 3809 [BTF_KIND_VAR] = &var_ops, 3810 [BTF_KIND_DATASEC] = &datasec_ops, 3811 }; 3812 3813 static s32 btf_check_meta(struct btf_verifier_env *env, 3814 const struct btf_type *t, 3815 u32 meta_left) 3816 { 3817 u32 saved_meta_left = meta_left; 3818 s32 var_meta_size; 3819 3820 if (meta_left < sizeof(*t)) { 3821 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu", 3822 env->log_type_id, meta_left, sizeof(*t)); 3823 return -EINVAL; 3824 } 3825 meta_left -= sizeof(*t); 3826 3827 if (t->info & ~BTF_INFO_MASK) { 3828 btf_verifier_log(env, "[%u] Invalid btf_info:%x", 3829 env->log_type_id, t->info); 3830 return -EINVAL; 3831 } 3832 3833 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX || 3834 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) { 3835 btf_verifier_log(env, "[%u] Invalid kind:%u", 3836 env->log_type_id, BTF_INFO_KIND(t->info)); 3837 return -EINVAL; 3838 } 3839 3840 if (!btf_name_offset_valid(env->btf, t->name_off)) { 3841 btf_verifier_log(env, "[%u] Invalid name_offset:%u", 3842 env->log_type_id, t->name_off); 3843 return -EINVAL; 3844 } 3845 3846 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left); 3847 if (var_meta_size < 0) 3848 return var_meta_size; 3849 3850 meta_left -= var_meta_size; 3851 3852 return saved_meta_left - meta_left; 3853 } 3854 3855 static int btf_check_all_metas(struct btf_verifier_env *env) 3856 { 3857 struct btf *btf = env->btf; 3858 struct btf_header *hdr; 3859 void *cur, *end; 3860 3861 hdr = &btf->hdr; 3862 cur = btf->nohdr_data + hdr->type_off; 3863 end = cur + hdr->type_len; 3864 3865 env->log_type_id = btf->base_btf ? btf->start_id : 1; 3866 while (cur < end) { 3867 struct btf_type *t = cur; 3868 s32 meta_size; 3869 3870 meta_size = btf_check_meta(env, t, end - cur); 3871 if (meta_size < 0) 3872 return meta_size; 3873 3874 btf_add_type(env, t); 3875 cur += meta_size; 3876 env->log_type_id++; 3877 } 3878 3879 return 0; 3880 } 3881 3882 static bool btf_resolve_valid(struct btf_verifier_env *env, 3883 const struct btf_type *t, 3884 u32 type_id) 3885 { 3886 struct btf *btf = env->btf; 3887 3888 if (!env_type_is_resolved(env, type_id)) 3889 return false; 3890 3891 if (btf_type_is_struct(t) || btf_type_is_datasec(t)) 3892 return !btf_resolved_type_id(btf, type_id) && 3893 !btf_resolved_type_size(btf, type_id); 3894 3895 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) || 3896 btf_type_is_var(t)) { 3897 t = btf_type_id_resolve(btf, &type_id); 3898 return t && 3899 !btf_type_is_modifier(t) && 3900 !btf_type_is_var(t) && 3901 !btf_type_is_datasec(t); 3902 } 3903 3904 if (btf_type_is_array(t)) { 3905 const struct btf_array *array = btf_type_array(t); 3906 const struct btf_type *elem_type; 3907 u32 elem_type_id = array->type; 3908 u32 elem_size; 3909 3910 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); 3911 return elem_type && !btf_type_is_modifier(elem_type) && 3912 (array->nelems * elem_size == 3913 btf_resolved_type_size(btf, type_id)); 3914 } 3915 3916 return false; 3917 } 3918 3919 static int btf_resolve(struct btf_verifier_env *env, 3920 const struct btf_type *t, u32 type_id) 3921 { 3922 u32 save_log_type_id = env->log_type_id; 3923 const struct resolve_vertex *v; 3924 int err = 0; 3925 3926 env->resolve_mode = RESOLVE_TBD; 3927 env_stack_push(env, t, type_id); 3928 while (!err && (v = env_stack_peak(env))) { 3929 env->log_type_id = v->type_id; 3930 err = btf_type_ops(v->t)->resolve(env, v); 3931 } 3932 3933 env->log_type_id = type_id; 3934 if (err == -E2BIG) { 3935 btf_verifier_log_type(env, t, 3936 "Exceeded max resolving depth:%u", 3937 MAX_RESOLVE_DEPTH); 3938 } else if (err == -EEXIST) { 3939 btf_verifier_log_type(env, t, "Loop detected"); 3940 } 3941 3942 /* Final sanity check */ 3943 if (!err && !btf_resolve_valid(env, t, type_id)) { 3944 btf_verifier_log_type(env, t, "Invalid resolve state"); 3945 err = -EINVAL; 3946 } 3947 3948 env->log_type_id = save_log_type_id; 3949 return err; 3950 } 3951 3952 static int btf_check_all_types(struct btf_verifier_env *env) 3953 { 3954 struct btf *btf = env->btf; 3955 const struct btf_type *t; 3956 u32 type_id, i; 3957 int err; 3958 3959 err = env_resolve_init(env); 3960 if (err) 3961 return err; 3962 3963 env->phase++; 3964 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) { 3965 type_id = btf->start_id + i; 3966 t = btf_type_by_id(btf, type_id); 3967 3968 env->log_type_id = type_id; 3969 if (btf_type_needs_resolve(t) && 3970 !env_type_is_resolved(env, type_id)) { 3971 err = btf_resolve(env, t, type_id); 3972 if (err) 3973 return err; 3974 } 3975 3976 if (btf_type_is_func_proto(t)) { 3977 err = btf_func_proto_check(env, t); 3978 if (err) 3979 return err; 3980 } 3981 3982 if (btf_type_is_func(t)) { 3983 err = btf_func_check(env, t); 3984 if (err) 3985 return err; 3986 } 3987 } 3988 3989 return 0; 3990 } 3991 3992 static int btf_parse_type_sec(struct btf_verifier_env *env) 3993 { 3994 const struct btf_header *hdr = &env->btf->hdr; 3995 int err; 3996 3997 /* Type section must align to 4 bytes */ 3998 if (hdr->type_off & (sizeof(u32) - 1)) { 3999 btf_verifier_log(env, "Unaligned type_off"); 4000 return -EINVAL; 4001 } 4002 4003 if (!env->btf->base_btf && !hdr->type_len) { 4004 btf_verifier_log(env, "No type found"); 4005 return -EINVAL; 4006 } 4007 4008 err = btf_check_all_metas(env); 4009 if (err) 4010 return err; 4011 4012 return btf_check_all_types(env); 4013 } 4014 4015 static int btf_parse_str_sec(struct btf_verifier_env *env) 4016 { 4017 const struct btf_header *hdr; 4018 struct btf *btf = env->btf; 4019 const char *start, *end; 4020 4021 hdr = &btf->hdr; 4022 start = btf->nohdr_data + hdr->str_off; 4023 end = start + hdr->str_len; 4024 4025 if (end != btf->data + btf->data_size) { 4026 btf_verifier_log(env, "String section is not at the end"); 4027 return -EINVAL; 4028 } 4029 4030 btf->strings = start; 4031 4032 if (btf->base_btf && !hdr->str_len) 4033 return 0; 4034 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) { 4035 btf_verifier_log(env, "Invalid string section"); 4036 return -EINVAL; 4037 } 4038 if (!btf->base_btf && start[0]) { 4039 btf_verifier_log(env, "Invalid string section"); 4040 return -EINVAL; 4041 } 4042 4043 return 0; 4044 } 4045 4046 static const size_t btf_sec_info_offset[] = { 4047 offsetof(struct btf_header, type_off), 4048 offsetof(struct btf_header, str_off), 4049 }; 4050 4051 static int btf_sec_info_cmp(const void *a, const void *b) 4052 { 4053 const struct btf_sec_info *x = a; 4054 const struct btf_sec_info *y = b; 4055 4056 return (int)(x->off - y->off) ? : (int)(x->len - y->len); 4057 } 4058 4059 static int btf_check_sec_info(struct btf_verifier_env *env, 4060 u32 btf_data_size) 4061 { 4062 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)]; 4063 u32 total, expected_total, i; 4064 const struct btf_header *hdr; 4065 const struct btf *btf; 4066 4067 btf = env->btf; 4068 hdr = &btf->hdr; 4069 4070 /* Populate the secs from hdr */ 4071 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) 4072 secs[i] = *(struct btf_sec_info *)((void *)hdr + 4073 btf_sec_info_offset[i]); 4074 4075 sort(secs, ARRAY_SIZE(btf_sec_info_offset), 4076 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL); 4077 4078 /* Check for gaps and overlap among sections */ 4079 total = 0; 4080 expected_total = btf_data_size - hdr->hdr_len; 4081 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) { 4082 if (expected_total < secs[i].off) { 4083 btf_verifier_log(env, "Invalid section offset"); 4084 return -EINVAL; 4085 } 4086 if (total < secs[i].off) { 4087 /* gap */ 4088 btf_verifier_log(env, "Unsupported section found"); 4089 return -EINVAL; 4090 } 4091 if (total > secs[i].off) { 4092 btf_verifier_log(env, "Section overlap found"); 4093 return -EINVAL; 4094 } 4095 if (expected_total - total < secs[i].len) { 4096 btf_verifier_log(env, 4097 "Total section length too long"); 4098 return -EINVAL; 4099 } 4100 total += secs[i].len; 4101 } 4102 4103 /* There is data other than hdr and known sections */ 4104 if (expected_total != total) { 4105 btf_verifier_log(env, "Unsupported section found"); 4106 return -EINVAL; 4107 } 4108 4109 return 0; 4110 } 4111 4112 static int btf_parse_hdr(struct btf_verifier_env *env) 4113 { 4114 u32 hdr_len, hdr_copy, btf_data_size; 4115 const struct btf_header *hdr; 4116 struct btf *btf; 4117 int err; 4118 4119 btf = env->btf; 4120 btf_data_size = btf->data_size; 4121 4122 if (btf_data_size < 4123 offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) { 4124 btf_verifier_log(env, "hdr_len not found"); 4125 return -EINVAL; 4126 } 4127 4128 hdr = btf->data; 4129 hdr_len = hdr->hdr_len; 4130 if (btf_data_size < hdr_len) { 4131 btf_verifier_log(env, "btf_header not found"); 4132 return -EINVAL; 4133 } 4134 4135 /* Ensure the unsupported header fields are zero */ 4136 if (hdr_len > sizeof(btf->hdr)) { 4137 u8 *expected_zero = btf->data + sizeof(btf->hdr); 4138 u8 *end = btf->data + hdr_len; 4139 4140 for (; expected_zero < end; expected_zero++) { 4141 if (*expected_zero) { 4142 btf_verifier_log(env, "Unsupported btf_header"); 4143 return -E2BIG; 4144 } 4145 } 4146 } 4147 4148 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr)); 4149 memcpy(&btf->hdr, btf->data, hdr_copy); 4150 4151 hdr = &btf->hdr; 4152 4153 btf_verifier_log_hdr(env, btf_data_size); 4154 4155 if (hdr->magic != BTF_MAGIC) { 4156 btf_verifier_log(env, "Invalid magic"); 4157 return -EINVAL; 4158 } 4159 4160 if (hdr->version != BTF_VERSION) { 4161 btf_verifier_log(env, "Unsupported version"); 4162 return -ENOTSUPP; 4163 } 4164 4165 if (hdr->flags) { 4166 btf_verifier_log(env, "Unsupported flags"); 4167 return -ENOTSUPP; 4168 } 4169 4170 if (!btf->base_btf && btf_data_size == hdr->hdr_len) { 4171 btf_verifier_log(env, "No data"); 4172 return -EINVAL; 4173 } 4174 4175 err = btf_check_sec_info(env, btf_data_size); 4176 if (err) 4177 return err; 4178 4179 return 0; 4180 } 4181 4182 static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size, 4183 u32 log_level, char __user *log_ubuf, u32 log_size) 4184 { 4185 struct btf_verifier_env *env = NULL; 4186 struct bpf_verifier_log *log; 4187 struct btf *btf = NULL; 4188 u8 *data; 4189 int err; 4190 4191 if (btf_data_size > BTF_MAX_SIZE) 4192 return ERR_PTR(-E2BIG); 4193 4194 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); 4195 if (!env) 4196 return ERR_PTR(-ENOMEM); 4197 4198 log = &env->log; 4199 if (log_level || log_ubuf || log_size) { 4200 /* user requested verbose verifier output 4201 * and supplied buffer to store the verification trace 4202 */ 4203 log->level = log_level; 4204 log->ubuf = log_ubuf; 4205 log->len_total = log_size; 4206 4207 /* log attributes have to be sane */ 4208 if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 || 4209 !log->level || !log->ubuf) { 4210 err = -EINVAL; 4211 goto errout; 4212 } 4213 } 4214 4215 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); 4216 if (!btf) { 4217 err = -ENOMEM; 4218 goto errout; 4219 } 4220 env->btf = btf; 4221 4222 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN); 4223 if (!data) { 4224 err = -ENOMEM; 4225 goto errout; 4226 } 4227 4228 btf->data = data; 4229 btf->data_size = btf_data_size; 4230 4231 if (copy_from_user(data, btf_data, btf_data_size)) { 4232 err = -EFAULT; 4233 goto errout; 4234 } 4235 4236 err = btf_parse_hdr(env); 4237 if (err) 4238 goto errout; 4239 4240 btf->nohdr_data = btf->data + btf->hdr.hdr_len; 4241 4242 err = btf_parse_str_sec(env); 4243 if (err) 4244 goto errout; 4245 4246 err = btf_parse_type_sec(env); 4247 if (err) 4248 goto errout; 4249 4250 if (log->level && bpf_verifier_log_full(log)) { 4251 err = -ENOSPC; 4252 goto errout; 4253 } 4254 4255 btf_verifier_env_free(env); 4256 refcount_set(&btf->refcnt, 1); 4257 return btf; 4258 4259 errout: 4260 btf_verifier_env_free(env); 4261 if (btf) 4262 btf_free(btf); 4263 return ERR_PTR(err); 4264 } 4265 4266 extern char __weak __start_BTF[]; 4267 extern char __weak __stop_BTF[]; 4268 extern struct btf *btf_vmlinux; 4269 4270 #define BPF_MAP_TYPE(_id, _ops) 4271 #define BPF_LINK_TYPE(_id, _name) 4272 static union { 4273 struct bpf_ctx_convert { 4274 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ 4275 prog_ctx_type _id##_prog; \ 4276 kern_ctx_type _id##_kern; 4277 #include <linux/bpf_types.h> 4278 #undef BPF_PROG_TYPE 4279 } *__t; 4280 /* 't' is written once under lock. Read many times. */ 4281 const struct btf_type *t; 4282 } bpf_ctx_convert; 4283 enum { 4284 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ 4285 __ctx_convert##_id, 4286 #include <linux/bpf_types.h> 4287 #undef BPF_PROG_TYPE 4288 __ctx_convert_unused, /* to avoid empty enum in extreme .config */ 4289 }; 4290 static u8 bpf_ctx_convert_map[] = { 4291 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ 4292 [_id] = __ctx_convert##_id, 4293 #include <linux/bpf_types.h> 4294 #undef BPF_PROG_TYPE 4295 0, /* avoid empty array */ 4296 }; 4297 #undef BPF_MAP_TYPE 4298 #undef BPF_LINK_TYPE 4299 4300 static const struct btf_member * 4301 btf_get_prog_ctx_type(struct bpf_verifier_log *log, struct btf *btf, 4302 const struct btf_type *t, enum bpf_prog_type prog_type, 4303 int arg) 4304 { 4305 const struct btf_type *conv_struct; 4306 const struct btf_type *ctx_struct; 4307 const struct btf_member *ctx_type; 4308 const char *tname, *ctx_tname; 4309 4310 conv_struct = bpf_ctx_convert.t; 4311 if (!conv_struct) { 4312 bpf_log(log, "btf_vmlinux is malformed\n"); 4313 return NULL; 4314 } 4315 t = btf_type_by_id(btf, t->type); 4316 while (btf_type_is_modifier(t)) 4317 t = btf_type_by_id(btf, t->type); 4318 if (!btf_type_is_struct(t)) { 4319 /* Only pointer to struct is supported for now. 4320 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF 4321 * is not supported yet. 4322 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine. 4323 */ 4324 if (log->level & BPF_LOG_LEVEL) 4325 bpf_log(log, "arg#%d type is not a struct\n", arg); 4326 return NULL; 4327 } 4328 tname = btf_name_by_offset(btf, t->name_off); 4329 if (!tname) { 4330 bpf_log(log, "arg#%d struct doesn't have a name\n", arg); 4331 return NULL; 4332 } 4333 /* prog_type is valid bpf program type. No need for bounds check. */ 4334 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2; 4335 /* ctx_struct is a pointer to prog_ctx_type in vmlinux. 4336 * Like 'struct __sk_buff' 4337 */ 4338 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type); 4339 if (!ctx_struct) 4340 /* should not happen */ 4341 return NULL; 4342 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off); 4343 if (!ctx_tname) { 4344 /* should not happen */ 4345 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n"); 4346 return NULL; 4347 } 4348 /* only compare that prog's ctx type name is the same as 4349 * kernel expects. No need to compare field by field. 4350 * It's ok for bpf prog to do: 4351 * struct __sk_buff {}; 4352 * int socket_filter_bpf_prog(struct __sk_buff *skb) 4353 * { // no fields of skb are ever used } 4354 */ 4355 if (strcmp(ctx_tname, tname)) 4356 return NULL; 4357 return ctx_type; 4358 } 4359 4360 static const struct bpf_map_ops * const btf_vmlinux_map_ops[] = { 4361 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) 4362 #define BPF_LINK_TYPE(_id, _name) 4363 #define BPF_MAP_TYPE(_id, _ops) \ 4364 [_id] = &_ops, 4365 #include <linux/bpf_types.h> 4366 #undef BPF_PROG_TYPE 4367 #undef BPF_LINK_TYPE 4368 #undef BPF_MAP_TYPE 4369 }; 4370 4371 static int btf_vmlinux_map_ids_init(const struct btf *btf, 4372 struct bpf_verifier_log *log) 4373 { 4374 const struct bpf_map_ops *ops; 4375 int i, btf_id; 4376 4377 for (i = 0; i < ARRAY_SIZE(btf_vmlinux_map_ops); ++i) { 4378 ops = btf_vmlinux_map_ops[i]; 4379 if (!ops || (!ops->map_btf_name && !ops->map_btf_id)) 4380 continue; 4381 if (!ops->map_btf_name || !ops->map_btf_id) { 4382 bpf_log(log, "map type %d is misconfigured\n", i); 4383 return -EINVAL; 4384 } 4385 btf_id = btf_find_by_name_kind(btf, ops->map_btf_name, 4386 BTF_KIND_STRUCT); 4387 if (btf_id < 0) 4388 return btf_id; 4389 *ops->map_btf_id = btf_id; 4390 } 4391 4392 return 0; 4393 } 4394 4395 static int btf_translate_to_vmlinux(struct bpf_verifier_log *log, 4396 struct btf *btf, 4397 const struct btf_type *t, 4398 enum bpf_prog_type prog_type, 4399 int arg) 4400 { 4401 const struct btf_member *prog_ctx_type, *kern_ctx_type; 4402 4403 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg); 4404 if (!prog_ctx_type) 4405 return -ENOENT; 4406 kern_ctx_type = prog_ctx_type + 1; 4407 return kern_ctx_type->type; 4408 } 4409 4410 BTF_ID_LIST(bpf_ctx_convert_btf_id) 4411 BTF_ID(struct, bpf_ctx_convert) 4412 4413 struct btf *btf_parse_vmlinux(void) 4414 { 4415 struct btf_verifier_env *env = NULL; 4416 struct bpf_verifier_log *log; 4417 struct btf *btf = NULL; 4418 int err; 4419 4420 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); 4421 if (!env) 4422 return ERR_PTR(-ENOMEM); 4423 4424 log = &env->log; 4425 log->level = BPF_LOG_KERNEL; 4426 4427 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); 4428 if (!btf) { 4429 err = -ENOMEM; 4430 goto errout; 4431 } 4432 env->btf = btf; 4433 4434 btf->data = __start_BTF; 4435 btf->data_size = __stop_BTF - __start_BTF; 4436 btf->kernel_btf = true; 4437 snprintf(btf->name, sizeof(btf->name), "vmlinux"); 4438 4439 err = btf_parse_hdr(env); 4440 if (err) 4441 goto errout; 4442 4443 btf->nohdr_data = btf->data + btf->hdr.hdr_len; 4444 4445 err = btf_parse_str_sec(env); 4446 if (err) 4447 goto errout; 4448 4449 err = btf_check_all_metas(env); 4450 if (err) 4451 goto errout; 4452 4453 /* btf_parse_vmlinux() runs under bpf_verifier_lock */ 4454 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]); 4455 4456 /* find bpf map structs for map_ptr access checking */ 4457 err = btf_vmlinux_map_ids_init(btf, log); 4458 if (err < 0) 4459 goto errout; 4460 4461 bpf_struct_ops_init(btf, log); 4462 4463 refcount_set(&btf->refcnt, 1); 4464 4465 err = btf_alloc_id(btf); 4466 if (err) 4467 goto errout; 4468 4469 btf_verifier_env_free(env); 4470 return btf; 4471 4472 errout: 4473 btf_verifier_env_free(env); 4474 if (btf) { 4475 kvfree(btf->types); 4476 kfree(btf); 4477 } 4478 return ERR_PTR(err); 4479 } 4480 4481 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES 4482 4483 static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size) 4484 { 4485 struct btf_verifier_env *env = NULL; 4486 struct bpf_verifier_log *log; 4487 struct btf *btf = NULL, *base_btf; 4488 int err; 4489 4490 base_btf = bpf_get_btf_vmlinux(); 4491 if (IS_ERR(base_btf)) 4492 return base_btf; 4493 if (!base_btf) 4494 return ERR_PTR(-EINVAL); 4495 4496 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); 4497 if (!env) 4498 return ERR_PTR(-ENOMEM); 4499 4500 log = &env->log; 4501 log->level = BPF_LOG_KERNEL; 4502 4503 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); 4504 if (!btf) { 4505 err = -ENOMEM; 4506 goto errout; 4507 } 4508 env->btf = btf; 4509 4510 btf->base_btf = base_btf; 4511 btf->start_id = base_btf->nr_types; 4512 btf->start_str_off = base_btf->hdr.str_len; 4513 btf->kernel_btf = true; 4514 snprintf(btf->name, sizeof(btf->name), "%s", module_name); 4515 4516 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN); 4517 if (!btf->data) { 4518 err = -ENOMEM; 4519 goto errout; 4520 } 4521 memcpy(btf->data, data, data_size); 4522 btf->data_size = data_size; 4523 4524 err = btf_parse_hdr(env); 4525 if (err) 4526 goto errout; 4527 4528 btf->nohdr_data = btf->data + btf->hdr.hdr_len; 4529 4530 err = btf_parse_str_sec(env); 4531 if (err) 4532 goto errout; 4533 4534 err = btf_check_all_metas(env); 4535 if (err) 4536 goto errout; 4537 4538 btf_verifier_env_free(env); 4539 refcount_set(&btf->refcnt, 1); 4540 return btf; 4541 4542 errout: 4543 btf_verifier_env_free(env); 4544 if (btf) { 4545 kvfree(btf->data); 4546 kvfree(btf->types); 4547 kfree(btf); 4548 } 4549 return ERR_PTR(err); 4550 } 4551 4552 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */ 4553 4554 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog) 4555 { 4556 struct bpf_prog *tgt_prog = prog->aux->dst_prog; 4557 4558 if (tgt_prog) 4559 return tgt_prog->aux->btf; 4560 else 4561 return prog->aux->attach_btf; 4562 } 4563 4564 static bool is_string_ptr(struct btf *btf, const struct btf_type *t) 4565 { 4566 /* t comes in already as a pointer */ 4567 t = btf_type_by_id(btf, t->type); 4568 4569 /* allow const */ 4570 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST) 4571 t = btf_type_by_id(btf, t->type); 4572 4573 /* char, signed char, unsigned char */ 4574 return btf_type_is_int(t) && t->size == 1; 4575 } 4576 4577 bool btf_ctx_access(int off, int size, enum bpf_access_type type, 4578 const struct bpf_prog *prog, 4579 struct bpf_insn_access_aux *info) 4580 { 4581 const struct btf_type *t = prog->aux->attach_func_proto; 4582 struct bpf_prog *tgt_prog = prog->aux->dst_prog; 4583 struct btf *btf = bpf_prog_get_target_btf(prog); 4584 const char *tname = prog->aux->attach_func_name; 4585 struct bpf_verifier_log *log = info->log; 4586 const struct btf_param *args; 4587 u32 nr_args, arg; 4588 int i, ret; 4589 4590 if (off % 8) { 4591 bpf_log(log, "func '%s' offset %d is not multiple of 8\n", 4592 tname, off); 4593 return false; 4594 } 4595 arg = off / 8; 4596 args = (const struct btf_param *)(t + 1); 4597 /* if (t == NULL) Fall back to default BPF prog with 5 u64 arguments */ 4598 nr_args = t ? btf_type_vlen(t) : 5; 4599 if (prog->aux->attach_btf_trace) { 4600 /* skip first 'void *__data' argument in btf_trace_##name typedef */ 4601 args++; 4602 nr_args--; 4603 } 4604 4605 if (arg > nr_args) { 4606 bpf_log(log, "func '%s' doesn't have %d-th argument\n", 4607 tname, arg + 1); 4608 return false; 4609 } 4610 4611 if (arg == nr_args) { 4612 switch (prog->expected_attach_type) { 4613 case BPF_LSM_MAC: 4614 case BPF_TRACE_FEXIT: 4615 /* When LSM programs are attached to void LSM hooks 4616 * they use FEXIT trampolines and when attached to 4617 * int LSM hooks, they use MODIFY_RETURN trampolines. 4618 * 4619 * While the LSM programs are BPF_MODIFY_RETURN-like 4620 * the check: 4621 * 4622 * if (ret_type != 'int') 4623 * return -EINVAL; 4624 * 4625 * is _not_ done here. This is still safe as LSM hooks 4626 * have only void and int return types. 4627 */ 4628 if (!t) 4629 return true; 4630 t = btf_type_by_id(btf, t->type); 4631 break; 4632 case BPF_MODIFY_RETURN: 4633 /* For now the BPF_MODIFY_RETURN can only be attached to 4634 * functions that return an int. 4635 */ 4636 if (!t) 4637 return false; 4638 4639 t = btf_type_skip_modifiers(btf, t->type, NULL); 4640 if (!btf_type_is_small_int(t)) { 4641 bpf_log(log, 4642 "ret type %s not allowed for fmod_ret\n", 4643 btf_kind_str[BTF_INFO_KIND(t->info)]); 4644 return false; 4645 } 4646 break; 4647 default: 4648 bpf_log(log, "func '%s' doesn't have %d-th argument\n", 4649 tname, arg + 1); 4650 return false; 4651 } 4652 } else { 4653 if (!t) 4654 /* Default prog with 5 args */ 4655 return true; 4656 t = btf_type_by_id(btf, args[arg].type); 4657 } 4658 4659 /* skip modifiers */ 4660 while (btf_type_is_modifier(t)) 4661 t = btf_type_by_id(btf, t->type); 4662 if (btf_type_is_small_int(t) || btf_type_is_enum(t)) 4663 /* accessing a scalar */ 4664 return true; 4665 if (!btf_type_is_ptr(t)) { 4666 bpf_log(log, 4667 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n", 4668 tname, arg, 4669 __btf_name_by_offset(btf, t->name_off), 4670 btf_kind_str[BTF_INFO_KIND(t->info)]); 4671 return false; 4672 } 4673 4674 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */ 4675 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) { 4676 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i]; 4677 4678 if (ctx_arg_info->offset == off && 4679 (ctx_arg_info->reg_type == PTR_TO_RDONLY_BUF_OR_NULL || 4680 ctx_arg_info->reg_type == PTR_TO_RDWR_BUF_OR_NULL)) { 4681 info->reg_type = ctx_arg_info->reg_type; 4682 return true; 4683 } 4684 } 4685 4686 if (t->type == 0) 4687 /* This is a pointer to void. 4688 * It is the same as scalar from the verifier safety pov. 4689 * No further pointer walking is allowed. 4690 */ 4691 return true; 4692 4693 if (is_string_ptr(btf, t)) 4694 return true; 4695 4696 /* this is a pointer to another type */ 4697 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) { 4698 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i]; 4699 4700 if (ctx_arg_info->offset == off) { 4701 info->reg_type = ctx_arg_info->reg_type; 4702 info->btf = btf_vmlinux; 4703 info->btf_id = ctx_arg_info->btf_id; 4704 return true; 4705 } 4706 } 4707 4708 info->reg_type = PTR_TO_BTF_ID; 4709 if (tgt_prog) { 4710 enum bpf_prog_type tgt_type; 4711 4712 if (tgt_prog->type == BPF_PROG_TYPE_EXT) 4713 tgt_type = tgt_prog->aux->saved_dst_prog_type; 4714 else 4715 tgt_type = tgt_prog->type; 4716 4717 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg); 4718 if (ret > 0) { 4719 info->btf = btf_vmlinux; 4720 info->btf_id = ret; 4721 return true; 4722 } else { 4723 return false; 4724 } 4725 } 4726 4727 info->btf = btf; 4728 info->btf_id = t->type; 4729 t = btf_type_by_id(btf, t->type); 4730 /* skip modifiers */ 4731 while (btf_type_is_modifier(t)) { 4732 info->btf_id = t->type; 4733 t = btf_type_by_id(btf, t->type); 4734 } 4735 if (!btf_type_is_struct(t)) { 4736 bpf_log(log, 4737 "func '%s' arg%d type %s is not a struct\n", 4738 tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]); 4739 return false; 4740 } 4741 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n", 4742 tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)], 4743 __btf_name_by_offset(btf, t->name_off)); 4744 return true; 4745 } 4746 4747 enum bpf_struct_walk_result { 4748 /* < 0 error */ 4749 WALK_SCALAR = 0, 4750 WALK_PTR, 4751 WALK_STRUCT, 4752 }; 4753 4754 static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, 4755 const struct btf_type *t, int off, int size, 4756 u32 *next_btf_id) 4757 { 4758 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0; 4759 const struct btf_type *mtype, *elem_type = NULL; 4760 const struct btf_member *member; 4761 const char *tname, *mname; 4762 u32 vlen, elem_id, mid; 4763 4764 again: 4765 tname = __btf_name_by_offset(btf, t->name_off); 4766 if (!btf_type_is_struct(t)) { 4767 bpf_log(log, "Type '%s' is not a struct\n", tname); 4768 return -EINVAL; 4769 } 4770 4771 vlen = btf_type_vlen(t); 4772 if (off + size > t->size) { 4773 /* If the last element is a variable size array, we may 4774 * need to relax the rule. 4775 */ 4776 struct btf_array *array_elem; 4777 4778 if (vlen == 0) 4779 goto error; 4780 4781 member = btf_type_member(t) + vlen - 1; 4782 mtype = btf_type_skip_modifiers(btf, member->type, 4783 NULL); 4784 if (!btf_type_is_array(mtype)) 4785 goto error; 4786 4787 array_elem = (struct btf_array *)(mtype + 1); 4788 if (array_elem->nelems != 0) 4789 goto error; 4790 4791 moff = btf_member_bit_offset(t, member) / 8; 4792 if (off < moff) 4793 goto error; 4794 4795 /* Only allow structure for now, can be relaxed for 4796 * other types later. 4797 */ 4798 t = btf_type_skip_modifiers(btf, array_elem->type, 4799 NULL); 4800 if (!btf_type_is_struct(t)) 4801 goto error; 4802 4803 off = (off - moff) % t->size; 4804 goto again; 4805 4806 error: 4807 bpf_log(log, "access beyond struct %s at off %u size %u\n", 4808 tname, off, size); 4809 return -EACCES; 4810 } 4811 4812 for_each_member(i, t, member) { 4813 /* offset of the field in bytes */ 4814 moff = btf_member_bit_offset(t, member) / 8; 4815 if (off + size <= moff) 4816 /* won't find anything, field is already too far */ 4817 break; 4818 4819 if (btf_member_bitfield_size(t, member)) { 4820 u32 end_bit = btf_member_bit_offset(t, member) + 4821 btf_member_bitfield_size(t, member); 4822 4823 /* off <= moff instead of off == moff because clang 4824 * does not generate a BTF member for anonymous 4825 * bitfield like the ":16" here: 4826 * struct { 4827 * int :16; 4828 * int x:8; 4829 * }; 4830 */ 4831 if (off <= moff && 4832 BITS_ROUNDUP_BYTES(end_bit) <= off + size) 4833 return WALK_SCALAR; 4834 4835 /* off may be accessing a following member 4836 * 4837 * or 4838 * 4839 * Doing partial access at either end of this 4840 * bitfield. Continue on this case also to 4841 * treat it as not accessing this bitfield 4842 * and eventually error out as field not 4843 * found to keep it simple. 4844 * It could be relaxed if there was a legit 4845 * partial access case later. 4846 */ 4847 continue; 4848 } 4849 4850 /* In case of "off" is pointing to holes of a struct */ 4851 if (off < moff) 4852 break; 4853 4854 /* type of the field */ 4855 mid = member->type; 4856 mtype = btf_type_by_id(btf, member->type); 4857 mname = __btf_name_by_offset(btf, member->name_off); 4858 4859 mtype = __btf_resolve_size(btf, mtype, &msize, 4860 &elem_type, &elem_id, &total_nelems, 4861 &mid); 4862 if (IS_ERR(mtype)) { 4863 bpf_log(log, "field %s doesn't have size\n", mname); 4864 return -EFAULT; 4865 } 4866 4867 mtrue_end = moff + msize; 4868 if (off >= mtrue_end) 4869 /* no overlap with member, keep iterating */ 4870 continue; 4871 4872 if (btf_type_is_array(mtype)) { 4873 u32 elem_idx; 4874 4875 /* __btf_resolve_size() above helps to 4876 * linearize a multi-dimensional array. 4877 * 4878 * The logic here is treating an array 4879 * in a struct as the following way: 4880 * 4881 * struct outer { 4882 * struct inner array[2][2]; 4883 * }; 4884 * 4885 * looks like: 4886 * 4887 * struct outer { 4888 * struct inner array_elem0; 4889 * struct inner array_elem1; 4890 * struct inner array_elem2; 4891 * struct inner array_elem3; 4892 * }; 4893 * 4894 * When accessing outer->array[1][0], it moves 4895 * moff to "array_elem2", set mtype to 4896 * "struct inner", and msize also becomes 4897 * sizeof(struct inner). Then most of the 4898 * remaining logic will fall through without 4899 * caring the current member is an array or 4900 * not. 4901 * 4902 * Unlike mtype/msize/moff, mtrue_end does not 4903 * change. The naming difference ("_true") tells 4904 * that it is not always corresponding to 4905 * the current mtype/msize/moff. 4906 * It is the true end of the current 4907 * member (i.e. array in this case). That 4908 * will allow an int array to be accessed like 4909 * a scratch space, 4910 * i.e. allow access beyond the size of 4911 * the array's element as long as it is 4912 * within the mtrue_end boundary. 4913 */ 4914 4915 /* skip empty array */ 4916 if (moff == mtrue_end) 4917 continue; 4918 4919 msize /= total_nelems; 4920 elem_idx = (off - moff) / msize; 4921 moff += elem_idx * msize; 4922 mtype = elem_type; 4923 mid = elem_id; 4924 } 4925 4926 /* the 'off' we're looking for is either equal to start 4927 * of this field or inside of this struct 4928 */ 4929 if (btf_type_is_struct(mtype)) { 4930 /* our field must be inside that union or struct */ 4931 t = mtype; 4932 4933 /* return if the offset matches the member offset */ 4934 if (off == moff) { 4935 *next_btf_id = mid; 4936 return WALK_STRUCT; 4937 } 4938 4939 /* adjust offset we're looking for */ 4940 off -= moff; 4941 goto again; 4942 } 4943 4944 if (btf_type_is_ptr(mtype)) { 4945 const struct btf_type *stype; 4946 u32 id; 4947 4948 if (msize != size || off != moff) { 4949 bpf_log(log, 4950 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n", 4951 mname, moff, tname, off, size); 4952 return -EACCES; 4953 } 4954 stype = btf_type_skip_modifiers(btf, mtype->type, &id); 4955 if (btf_type_is_struct(stype)) { 4956 *next_btf_id = id; 4957 return WALK_PTR; 4958 } 4959 } 4960 4961 /* Allow more flexible access within an int as long as 4962 * it is within mtrue_end. 4963 * Since mtrue_end could be the end of an array, 4964 * that also allows using an array of int as a scratch 4965 * space. e.g. skb->cb[]. 4966 */ 4967 if (off + size > mtrue_end) { 4968 bpf_log(log, 4969 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n", 4970 mname, mtrue_end, tname, off, size); 4971 return -EACCES; 4972 } 4973 4974 return WALK_SCALAR; 4975 } 4976 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off); 4977 return -EINVAL; 4978 } 4979 4980 int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, 4981 const struct btf_type *t, int off, int size, 4982 enum bpf_access_type atype __maybe_unused, 4983 u32 *next_btf_id) 4984 { 4985 int err; 4986 u32 id; 4987 4988 do { 4989 err = btf_struct_walk(log, btf, t, off, size, &id); 4990 4991 switch (err) { 4992 case WALK_PTR: 4993 /* If we found the pointer or scalar on t+off, 4994 * we're done. 4995 */ 4996 *next_btf_id = id; 4997 return PTR_TO_BTF_ID; 4998 case WALK_SCALAR: 4999 return SCALAR_VALUE; 5000 case WALK_STRUCT: 5001 /* We found nested struct, so continue the search 5002 * by diving in it. At this point the offset is 5003 * aligned with the new type, so set it to 0. 5004 */ 5005 t = btf_type_by_id(btf, id); 5006 off = 0; 5007 break; 5008 default: 5009 /* It's either error or unknown return value.. 5010 * scream and leave. 5011 */ 5012 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value")) 5013 return -EINVAL; 5014 return err; 5015 } 5016 } while (t); 5017 5018 return -EINVAL; 5019 } 5020 5021 /* Check that two BTF types, each specified as an BTF object + id, are exactly 5022 * the same. Trivial ID check is not enough due to module BTFs, because we can 5023 * end up with two different module BTFs, but IDs point to the common type in 5024 * vmlinux BTF. 5025 */ 5026 static bool btf_types_are_same(const struct btf *btf1, u32 id1, 5027 const struct btf *btf2, u32 id2) 5028 { 5029 if (id1 != id2) 5030 return false; 5031 if (btf1 == btf2) 5032 return true; 5033 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2); 5034 } 5035 5036 bool btf_struct_ids_match(struct bpf_verifier_log *log, 5037 const struct btf *btf, u32 id, int off, 5038 const struct btf *need_btf, u32 need_type_id) 5039 { 5040 const struct btf_type *type; 5041 int err; 5042 5043 /* Are we already done? */ 5044 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id)) 5045 return true; 5046 5047 again: 5048 type = btf_type_by_id(btf, id); 5049 if (!type) 5050 return false; 5051 err = btf_struct_walk(log, btf, type, off, 1, &id); 5052 if (err != WALK_STRUCT) 5053 return false; 5054 5055 /* We found nested struct object. If it matches 5056 * the requested ID, we're done. Otherwise let's 5057 * continue the search with offset 0 in the new 5058 * type. 5059 */ 5060 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) { 5061 off = 0; 5062 goto again; 5063 } 5064 5065 return true; 5066 } 5067 5068 static int __get_type_size(struct btf *btf, u32 btf_id, 5069 const struct btf_type **bad_type) 5070 { 5071 const struct btf_type *t; 5072 5073 if (!btf_id) 5074 /* void */ 5075 return 0; 5076 t = btf_type_by_id(btf, btf_id); 5077 while (t && btf_type_is_modifier(t)) 5078 t = btf_type_by_id(btf, t->type); 5079 if (!t) { 5080 *bad_type = btf_type_by_id(btf, 0); 5081 return -EINVAL; 5082 } 5083 if (btf_type_is_ptr(t)) 5084 /* kernel size of pointer. Not BPF's size of pointer*/ 5085 return sizeof(void *); 5086 if (btf_type_is_int(t) || btf_type_is_enum(t)) 5087 return t->size; 5088 *bad_type = t; 5089 return -EINVAL; 5090 } 5091 5092 int btf_distill_func_proto(struct bpf_verifier_log *log, 5093 struct btf *btf, 5094 const struct btf_type *func, 5095 const char *tname, 5096 struct btf_func_model *m) 5097 { 5098 const struct btf_param *args; 5099 const struct btf_type *t; 5100 u32 i, nargs; 5101 int ret; 5102 5103 if (!func) { 5104 /* BTF function prototype doesn't match the verifier types. 5105 * Fall back to 5 u64 args. 5106 */ 5107 for (i = 0; i < 5; i++) 5108 m->arg_size[i] = 8; 5109 m->ret_size = 8; 5110 m->nr_args = 5; 5111 return 0; 5112 } 5113 args = (const struct btf_param *)(func + 1); 5114 nargs = btf_type_vlen(func); 5115 if (nargs >= MAX_BPF_FUNC_ARGS) { 5116 bpf_log(log, 5117 "The function %s has %d arguments. Too many.\n", 5118 tname, nargs); 5119 return -EINVAL; 5120 } 5121 ret = __get_type_size(btf, func->type, &t); 5122 if (ret < 0) { 5123 bpf_log(log, 5124 "The function %s return type %s is unsupported.\n", 5125 tname, btf_kind_str[BTF_INFO_KIND(t->info)]); 5126 return -EINVAL; 5127 } 5128 m->ret_size = ret; 5129 5130 for (i = 0; i < nargs; i++) { 5131 ret = __get_type_size(btf, args[i].type, &t); 5132 if (ret < 0) { 5133 bpf_log(log, 5134 "The function %s arg%d type %s is unsupported.\n", 5135 tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]); 5136 return -EINVAL; 5137 } 5138 m->arg_size[i] = ret; 5139 } 5140 m->nr_args = nargs; 5141 return 0; 5142 } 5143 5144 /* Compare BTFs of two functions assuming only scalars and pointers to context. 5145 * t1 points to BTF_KIND_FUNC in btf1 5146 * t2 points to BTF_KIND_FUNC in btf2 5147 * Returns: 5148 * EINVAL - function prototype mismatch 5149 * EFAULT - verifier bug 5150 * 0 - 99% match. The last 1% is validated by the verifier. 5151 */ 5152 static int btf_check_func_type_match(struct bpf_verifier_log *log, 5153 struct btf *btf1, const struct btf_type *t1, 5154 struct btf *btf2, const struct btf_type *t2) 5155 { 5156 const struct btf_param *args1, *args2; 5157 const char *fn1, *fn2, *s1, *s2; 5158 u32 nargs1, nargs2, i; 5159 5160 fn1 = btf_name_by_offset(btf1, t1->name_off); 5161 fn2 = btf_name_by_offset(btf2, t2->name_off); 5162 5163 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) { 5164 bpf_log(log, "%s() is not a global function\n", fn1); 5165 return -EINVAL; 5166 } 5167 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) { 5168 bpf_log(log, "%s() is not a global function\n", fn2); 5169 return -EINVAL; 5170 } 5171 5172 t1 = btf_type_by_id(btf1, t1->type); 5173 if (!t1 || !btf_type_is_func_proto(t1)) 5174 return -EFAULT; 5175 t2 = btf_type_by_id(btf2, t2->type); 5176 if (!t2 || !btf_type_is_func_proto(t2)) 5177 return -EFAULT; 5178 5179 args1 = (const struct btf_param *)(t1 + 1); 5180 nargs1 = btf_type_vlen(t1); 5181 args2 = (const struct btf_param *)(t2 + 1); 5182 nargs2 = btf_type_vlen(t2); 5183 5184 if (nargs1 != nargs2) { 5185 bpf_log(log, "%s() has %d args while %s() has %d args\n", 5186 fn1, nargs1, fn2, nargs2); 5187 return -EINVAL; 5188 } 5189 5190 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL); 5191 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL); 5192 if (t1->info != t2->info) { 5193 bpf_log(log, 5194 "Return type %s of %s() doesn't match type %s of %s()\n", 5195 btf_type_str(t1), fn1, 5196 btf_type_str(t2), fn2); 5197 return -EINVAL; 5198 } 5199 5200 for (i = 0; i < nargs1; i++) { 5201 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL); 5202 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL); 5203 5204 if (t1->info != t2->info) { 5205 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n", 5206 i, fn1, btf_type_str(t1), 5207 fn2, btf_type_str(t2)); 5208 return -EINVAL; 5209 } 5210 if (btf_type_has_size(t1) && t1->size != t2->size) { 5211 bpf_log(log, 5212 "arg%d in %s() has size %d while %s() has %d\n", 5213 i, fn1, t1->size, 5214 fn2, t2->size); 5215 return -EINVAL; 5216 } 5217 5218 /* global functions are validated with scalars and pointers 5219 * to context only. And only global functions can be replaced. 5220 * Hence type check only those types. 5221 */ 5222 if (btf_type_is_int(t1) || btf_type_is_enum(t1)) 5223 continue; 5224 if (!btf_type_is_ptr(t1)) { 5225 bpf_log(log, 5226 "arg%d in %s() has unrecognized type\n", 5227 i, fn1); 5228 return -EINVAL; 5229 } 5230 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL); 5231 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL); 5232 if (!btf_type_is_struct(t1)) { 5233 bpf_log(log, 5234 "arg%d in %s() is not a pointer to context\n", 5235 i, fn1); 5236 return -EINVAL; 5237 } 5238 if (!btf_type_is_struct(t2)) { 5239 bpf_log(log, 5240 "arg%d in %s() is not a pointer to context\n", 5241 i, fn2); 5242 return -EINVAL; 5243 } 5244 /* This is an optional check to make program writing easier. 5245 * Compare names of structs and report an error to the user. 5246 * btf_prepare_func_args() already checked that t2 struct 5247 * is a context type. btf_prepare_func_args() will check 5248 * later that t1 struct is a context type as well. 5249 */ 5250 s1 = btf_name_by_offset(btf1, t1->name_off); 5251 s2 = btf_name_by_offset(btf2, t2->name_off); 5252 if (strcmp(s1, s2)) { 5253 bpf_log(log, 5254 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n", 5255 i, fn1, s1, fn2, s2); 5256 return -EINVAL; 5257 } 5258 } 5259 return 0; 5260 } 5261 5262 /* Compare BTFs of given program with BTF of target program */ 5263 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog, 5264 struct btf *btf2, const struct btf_type *t2) 5265 { 5266 struct btf *btf1 = prog->aux->btf; 5267 const struct btf_type *t1; 5268 u32 btf_id = 0; 5269 5270 if (!prog->aux->func_info) { 5271 bpf_log(log, "Program extension requires BTF\n"); 5272 return -EINVAL; 5273 } 5274 5275 btf_id = prog->aux->func_info[0].type_id; 5276 if (!btf_id) 5277 return -EFAULT; 5278 5279 t1 = btf_type_by_id(btf1, btf_id); 5280 if (!t1 || !btf_type_is_func(t1)) 5281 return -EFAULT; 5282 5283 return btf_check_func_type_match(log, btf1, t1, btf2, t2); 5284 } 5285 5286 /* Compare BTF of a function with given bpf_reg_state. 5287 * Returns: 5288 * EFAULT - there is a verifier bug. Abort verification. 5289 * EINVAL - there is a type mismatch or BTF is not available. 5290 * 0 - BTF matches with what bpf_reg_state expects. 5291 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized. 5292 */ 5293 int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, 5294 struct bpf_reg_state *regs) 5295 { 5296 struct bpf_verifier_log *log = &env->log; 5297 struct bpf_prog *prog = env->prog; 5298 struct btf *btf = prog->aux->btf; 5299 const struct btf_param *args; 5300 const struct btf_type *t, *ref_t; 5301 u32 i, nargs, btf_id, type_size; 5302 const char *tname; 5303 bool is_global; 5304 5305 if (!prog->aux->func_info) 5306 return -EINVAL; 5307 5308 btf_id = prog->aux->func_info[subprog].type_id; 5309 if (!btf_id) 5310 return -EFAULT; 5311 5312 if (prog->aux->func_info_aux[subprog].unreliable) 5313 return -EINVAL; 5314 5315 t = btf_type_by_id(btf, btf_id); 5316 if (!t || !btf_type_is_func(t)) { 5317 /* These checks were already done by the verifier while loading 5318 * struct bpf_func_info 5319 */ 5320 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n", 5321 subprog); 5322 return -EFAULT; 5323 } 5324 tname = btf_name_by_offset(btf, t->name_off); 5325 5326 t = btf_type_by_id(btf, t->type); 5327 if (!t || !btf_type_is_func_proto(t)) { 5328 bpf_log(log, "Invalid BTF of func %s\n", tname); 5329 return -EFAULT; 5330 } 5331 args = (const struct btf_param *)(t + 1); 5332 nargs = btf_type_vlen(t); 5333 if (nargs > 5) { 5334 bpf_log(log, "Function %s has %d > 5 args\n", tname, nargs); 5335 goto out; 5336 } 5337 5338 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; 5339 /* check that BTF function arguments match actual types that the 5340 * verifier sees. 5341 */ 5342 for (i = 0; i < nargs; i++) { 5343 struct bpf_reg_state *reg = ®s[i + 1]; 5344 5345 t = btf_type_by_id(btf, args[i].type); 5346 while (btf_type_is_modifier(t)) 5347 t = btf_type_by_id(btf, t->type); 5348 if (btf_type_is_int(t) || btf_type_is_enum(t)) { 5349 if (reg->type == SCALAR_VALUE) 5350 continue; 5351 bpf_log(log, "R%d is not a scalar\n", i + 1); 5352 goto out; 5353 } 5354 if (btf_type_is_ptr(t)) { 5355 /* If function expects ctx type in BTF check that caller 5356 * is passing PTR_TO_CTX. 5357 */ 5358 if (btf_get_prog_ctx_type(log, btf, t, prog->type, i)) { 5359 if (reg->type != PTR_TO_CTX) { 5360 bpf_log(log, 5361 "arg#%d expected pointer to ctx, but got %s\n", 5362 i, btf_kind_str[BTF_INFO_KIND(t->info)]); 5363 goto out; 5364 } 5365 if (check_ctx_reg(env, reg, i + 1)) 5366 goto out; 5367 continue; 5368 } 5369 5370 if (!is_global) 5371 goto out; 5372 5373 t = btf_type_skip_modifiers(btf, t->type, NULL); 5374 5375 ref_t = btf_resolve_size(btf, t, &type_size); 5376 if (IS_ERR(ref_t)) { 5377 bpf_log(log, 5378 "arg#%d reference type('%s %s') size cannot be determined: %ld\n", 5379 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off), 5380 PTR_ERR(ref_t)); 5381 goto out; 5382 } 5383 5384 if (check_mem_reg(env, reg, i + 1, type_size)) 5385 goto out; 5386 5387 continue; 5388 } 5389 bpf_log(log, "Unrecognized arg#%d type %s\n", 5390 i, btf_kind_str[BTF_INFO_KIND(t->info)]); 5391 goto out; 5392 } 5393 return 0; 5394 out: 5395 /* Compiler optimizations can remove arguments from static functions 5396 * or mismatched type can be passed into a global function. 5397 * In such cases mark the function as unreliable from BTF point of view. 5398 */ 5399 prog->aux->func_info_aux[subprog].unreliable = true; 5400 return -EINVAL; 5401 } 5402 5403 /* Convert BTF of a function into bpf_reg_state if possible 5404 * Returns: 5405 * EFAULT - there is a verifier bug. Abort verification. 5406 * EINVAL - cannot convert BTF. 5407 * 0 - Successfully converted BTF into bpf_reg_state 5408 * (either PTR_TO_CTX or SCALAR_VALUE). 5409 */ 5410 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, 5411 struct bpf_reg_state *regs) 5412 { 5413 struct bpf_verifier_log *log = &env->log; 5414 struct bpf_prog *prog = env->prog; 5415 enum bpf_prog_type prog_type = prog->type; 5416 struct btf *btf = prog->aux->btf; 5417 const struct btf_param *args; 5418 const struct btf_type *t, *ref_t; 5419 u32 i, nargs, btf_id; 5420 const char *tname; 5421 5422 if (!prog->aux->func_info || 5423 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) { 5424 bpf_log(log, "Verifier bug\n"); 5425 return -EFAULT; 5426 } 5427 5428 btf_id = prog->aux->func_info[subprog].type_id; 5429 if (!btf_id) { 5430 bpf_log(log, "Global functions need valid BTF\n"); 5431 return -EFAULT; 5432 } 5433 5434 t = btf_type_by_id(btf, btf_id); 5435 if (!t || !btf_type_is_func(t)) { 5436 /* These checks were already done by the verifier while loading 5437 * struct bpf_func_info 5438 */ 5439 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n", 5440 subprog); 5441 return -EFAULT; 5442 } 5443 tname = btf_name_by_offset(btf, t->name_off); 5444 5445 if (log->level & BPF_LOG_LEVEL) 5446 bpf_log(log, "Validating %s() func#%d...\n", 5447 tname, subprog); 5448 5449 if (prog->aux->func_info_aux[subprog].unreliable) { 5450 bpf_log(log, "Verifier bug in function %s()\n", tname); 5451 return -EFAULT; 5452 } 5453 if (prog_type == BPF_PROG_TYPE_EXT) 5454 prog_type = prog->aux->dst_prog->type; 5455 5456 t = btf_type_by_id(btf, t->type); 5457 if (!t || !btf_type_is_func_proto(t)) { 5458 bpf_log(log, "Invalid type of function %s()\n", tname); 5459 return -EFAULT; 5460 } 5461 args = (const struct btf_param *)(t + 1); 5462 nargs = btf_type_vlen(t); 5463 if (nargs > 5) { 5464 bpf_log(log, "Global function %s() with %d > 5 args. Buggy compiler.\n", 5465 tname, nargs); 5466 return -EINVAL; 5467 } 5468 /* check that function returns int */ 5469 t = btf_type_by_id(btf, t->type); 5470 while (btf_type_is_modifier(t)) 5471 t = btf_type_by_id(btf, t->type); 5472 if (!btf_type_is_int(t) && !btf_type_is_enum(t)) { 5473 bpf_log(log, 5474 "Global function %s() doesn't return scalar. Only those are supported.\n", 5475 tname); 5476 return -EINVAL; 5477 } 5478 /* Convert BTF function arguments into verifier types. 5479 * Only PTR_TO_CTX and SCALAR are supported atm. 5480 */ 5481 for (i = 0; i < nargs; i++) { 5482 struct bpf_reg_state *reg = ®s[i + 1]; 5483 5484 t = btf_type_by_id(btf, args[i].type); 5485 while (btf_type_is_modifier(t)) 5486 t = btf_type_by_id(btf, t->type); 5487 if (btf_type_is_int(t) || btf_type_is_enum(t)) { 5488 reg->type = SCALAR_VALUE; 5489 continue; 5490 } 5491 if (btf_type_is_ptr(t)) { 5492 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) { 5493 reg->type = PTR_TO_CTX; 5494 continue; 5495 } 5496 5497 t = btf_type_skip_modifiers(btf, t->type, NULL); 5498 5499 ref_t = btf_resolve_size(btf, t, ®->mem_size); 5500 if (IS_ERR(ref_t)) { 5501 bpf_log(log, 5502 "arg#%d reference type('%s %s') size cannot be determined: %ld\n", 5503 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off), 5504 PTR_ERR(ref_t)); 5505 return -EINVAL; 5506 } 5507 5508 reg->type = PTR_TO_MEM_OR_NULL; 5509 reg->id = ++env->id_gen; 5510 5511 continue; 5512 } 5513 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n", 5514 i, btf_kind_str[BTF_INFO_KIND(t->info)], tname); 5515 return -EINVAL; 5516 } 5517 return 0; 5518 } 5519 5520 static void btf_type_show(const struct btf *btf, u32 type_id, void *obj, 5521 struct btf_show *show) 5522 { 5523 const struct btf_type *t = btf_type_by_id(btf, type_id); 5524 5525 show->btf = btf; 5526 memset(&show->state, 0, sizeof(show->state)); 5527 memset(&show->obj, 0, sizeof(show->obj)); 5528 5529 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show); 5530 } 5531 5532 static void btf_seq_show(struct btf_show *show, const char *fmt, 5533 va_list args) 5534 { 5535 seq_vprintf((struct seq_file *)show->target, fmt, args); 5536 } 5537 5538 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id, 5539 void *obj, struct seq_file *m, u64 flags) 5540 { 5541 struct btf_show sseq; 5542 5543 sseq.target = m; 5544 sseq.showfn = btf_seq_show; 5545 sseq.flags = flags; 5546 5547 btf_type_show(btf, type_id, obj, &sseq); 5548 5549 return sseq.state.status; 5550 } 5551 5552 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj, 5553 struct seq_file *m) 5554 { 5555 (void) btf_type_seq_show_flags(btf, type_id, obj, m, 5556 BTF_SHOW_NONAME | BTF_SHOW_COMPACT | 5557 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE); 5558 } 5559 5560 struct btf_show_snprintf { 5561 struct btf_show show; 5562 int len_left; /* space left in string */ 5563 int len; /* length we would have written */ 5564 }; 5565 5566 static void btf_snprintf_show(struct btf_show *show, const char *fmt, 5567 va_list args) 5568 { 5569 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show; 5570 int len; 5571 5572 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args); 5573 5574 if (len < 0) { 5575 ssnprintf->len_left = 0; 5576 ssnprintf->len = len; 5577 } else if (len > ssnprintf->len_left) { 5578 /* no space, drive on to get length we would have written */ 5579 ssnprintf->len_left = 0; 5580 ssnprintf->len += len; 5581 } else { 5582 ssnprintf->len_left -= len; 5583 ssnprintf->len += len; 5584 show->target += len; 5585 } 5586 } 5587 5588 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj, 5589 char *buf, int len, u64 flags) 5590 { 5591 struct btf_show_snprintf ssnprintf; 5592 5593 ssnprintf.show.target = buf; 5594 ssnprintf.show.flags = flags; 5595 ssnprintf.show.showfn = btf_snprintf_show; 5596 ssnprintf.len_left = len; 5597 ssnprintf.len = 0; 5598 5599 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf); 5600 5601 /* If we encontered an error, return it. */ 5602 if (ssnprintf.show.state.status) 5603 return ssnprintf.show.state.status; 5604 5605 /* Otherwise return length we would have written */ 5606 return ssnprintf.len; 5607 } 5608 5609 #ifdef CONFIG_PROC_FS 5610 static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp) 5611 { 5612 const struct btf *btf = filp->private_data; 5613 5614 seq_printf(m, "btf_id:\t%u\n", btf->id); 5615 } 5616 #endif 5617 5618 static int btf_release(struct inode *inode, struct file *filp) 5619 { 5620 btf_put(filp->private_data); 5621 return 0; 5622 } 5623 5624 const struct file_operations btf_fops = { 5625 #ifdef CONFIG_PROC_FS 5626 .show_fdinfo = bpf_btf_show_fdinfo, 5627 #endif 5628 .release = btf_release, 5629 }; 5630 5631 static int __btf_new_fd(struct btf *btf) 5632 { 5633 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC); 5634 } 5635 5636 int btf_new_fd(const union bpf_attr *attr) 5637 { 5638 struct btf *btf; 5639 int ret; 5640 5641 btf = btf_parse(u64_to_user_ptr(attr->btf), 5642 attr->btf_size, attr->btf_log_level, 5643 u64_to_user_ptr(attr->btf_log_buf), 5644 attr->btf_log_size); 5645 if (IS_ERR(btf)) 5646 return PTR_ERR(btf); 5647 5648 ret = btf_alloc_id(btf); 5649 if (ret) { 5650 btf_free(btf); 5651 return ret; 5652 } 5653 5654 /* 5655 * The BTF ID is published to the userspace. 5656 * All BTF free must go through call_rcu() from 5657 * now on (i.e. free by calling btf_put()). 5658 */ 5659 5660 ret = __btf_new_fd(btf); 5661 if (ret < 0) 5662 btf_put(btf); 5663 5664 return ret; 5665 } 5666 5667 struct btf *btf_get_by_fd(int fd) 5668 { 5669 struct btf *btf; 5670 struct fd f; 5671 5672 f = fdget(fd); 5673 5674 if (!f.file) 5675 return ERR_PTR(-EBADF); 5676 5677 if (f.file->f_op != &btf_fops) { 5678 fdput(f); 5679 return ERR_PTR(-EINVAL); 5680 } 5681 5682 btf = f.file->private_data; 5683 refcount_inc(&btf->refcnt); 5684 fdput(f); 5685 5686 return btf; 5687 } 5688 5689 int btf_get_info_by_fd(const struct btf *btf, 5690 const union bpf_attr *attr, 5691 union bpf_attr __user *uattr) 5692 { 5693 struct bpf_btf_info __user *uinfo; 5694 struct bpf_btf_info info; 5695 u32 info_copy, btf_copy; 5696 void __user *ubtf; 5697 char __user *uname; 5698 u32 uinfo_len, uname_len, name_len; 5699 int ret = 0; 5700 5701 uinfo = u64_to_user_ptr(attr->info.info); 5702 uinfo_len = attr->info.info_len; 5703 5704 info_copy = min_t(u32, uinfo_len, sizeof(info)); 5705 memset(&info, 0, sizeof(info)); 5706 if (copy_from_user(&info, uinfo, info_copy)) 5707 return -EFAULT; 5708 5709 info.id = btf->id; 5710 ubtf = u64_to_user_ptr(info.btf); 5711 btf_copy = min_t(u32, btf->data_size, info.btf_size); 5712 if (copy_to_user(ubtf, btf->data, btf_copy)) 5713 return -EFAULT; 5714 info.btf_size = btf->data_size; 5715 5716 info.kernel_btf = btf->kernel_btf; 5717 5718 uname = u64_to_user_ptr(info.name); 5719 uname_len = info.name_len; 5720 if (!uname ^ !uname_len) 5721 return -EINVAL; 5722 5723 name_len = strlen(btf->name); 5724 info.name_len = name_len; 5725 5726 if (uname) { 5727 if (uname_len >= name_len + 1) { 5728 if (copy_to_user(uname, btf->name, name_len + 1)) 5729 return -EFAULT; 5730 } else { 5731 char zero = '\0'; 5732 5733 if (copy_to_user(uname, btf->name, uname_len - 1)) 5734 return -EFAULT; 5735 if (put_user(zero, uname + uname_len - 1)) 5736 return -EFAULT; 5737 /* let user-space know about too short buffer */ 5738 ret = -ENOSPC; 5739 } 5740 } 5741 5742 if (copy_to_user(uinfo, &info, info_copy) || 5743 put_user(info_copy, &uattr->info.info_len)) 5744 return -EFAULT; 5745 5746 return ret; 5747 } 5748 5749 int btf_get_fd_by_id(u32 id) 5750 { 5751 struct btf *btf; 5752 int fd; 5753 5754 rcu_read_lock(); 5755 btf = idr_find(&btf_idr, id); 5756 if (!btf || !refcount_inc_not_zero(&btf->refcnt)) 5757 btf = ERR_PTR(-ENOENT); 5758 rcu_read_unlock(); 5759 5760 if (IS_ERR(btf)) 5761 return PTR_ERR(btf); 5762 5763 fd = __btf_new_fd(btf); 5764 if (fd < 0) 5765 btf_put(btf); 5766 5767 return fd; 5768 } 5769 5770 u32 btf_obj_id(const struct btf *btf) 5771 { 5772 return btf->id; 5773 } 5774 5775 bool btf_is_kernel(const struct btf *btf) 5776 { 5777 return btf->kernel_btf; 5778 } 5779 5780 bool btf_is_module(const struct btf *btf) 5781 { 5782 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0; 5783 } 5784 5785 static int btf_id_cmp_func(const void *a, const void *b) 5786 { 5787 const int *pa = a, *pb = b; 5788 5789 return *pa - *pb; 5790 } 5791 5792 bool btf_id_set_contains(const struct btf_id_set *set, u32 id) 5793 { 5794 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL; 5795 } 5796 5797 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES 5798 struct btf_module { 5799 struct list_head list; 5800 struct module *module; 5801 struct btf *btf; 5802 struct bin_attribute *sysfs_attr; 5803 }; 5804 5805 static LIST_HEAD(btf_modules); 5806 static DEFINE_MUTEX(btf_module_mutex); 5807 5808 static ssize_t 5809 btf_module_read(struct file *file, struct kobject *kobj, 5810 struct bin_attribute *bin_attr, 5811 char *buf, loff_t off, size_t len) 5812 { 5813 const struct btf *btf = bin_attr->private; 5814 5815 memcpy(buf, btf->data + off, len); 5816 return len; 5817 } 5818 5819 static int btf_module_notify(struct notifier_block *nb, unsigned long op, 5820 void *module) 5821 { 5822 struct btf_module *btf_mod, *tmp; 5823 struct module *mod = module; 5824 struct btf *btf; 5825 int err = 0; 5826 5827 if (mod->btf_data_size == 0 || 5828 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) 5829 goto out; 5830 5831 switch (op) { 5832 case MODULE_STATE_COMING: 5833 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL); 5834 if (!btf_mod) { 5835 err = -ENOMEM; 5836 goto out; 5837 } 5838 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size); 5839 if (IS_ERR(btf)) { 5840 pr_warn("failed to validate module [%s] BTF: %ld\n", 5841 mod->name, PTR_ERR(btf)); 5842 kfree(btf_mod); 5843 err = PTR_ERR(btf); 5844 goto out; 5845 } 5846 err = btf_alloc_id(btf); 5847 if (err) { 5848 btf_free(btf); 5849 kfree(btf_mod); 5850 goto out; 5851 } 5852 5853 mutex_lock(&btf_module_mutex); 5854 btf_mod->module = module; 5855 btf_mod->btf = btf; 5856 list_add(&btf_mod->list, &btf_modules); 5857 mutex_unlock(&btf_module_mutex); 5858 5859 if (IS_ENABLED(CONFIG_SYSFS)) { 5860 struct bin_attribute *attr; 5861 5862 attr = kzalloc(sizeof(*attr), GFP_KERNEL); 5863 if (!attr) 5864 goto out; 5865 5866 sysfs_bin_attr_init(attr); 5867 attr->attr.name = btf->name; 5868 attr->attr.mode = 0444; 5869 attr->size = btf->data_size; 5870 attr->private = btf; 5871 attr->read = btf_module_read; 5872 5873 err = sysfs_create_bin_file(btf_kobj, attr); 5874 if (err) { 5875 pr_warn("failed to register module [%s] BTF in sysfs: %d\n", 5876 mod->name, err); 5877 kfree(attr); 5878 err = 0; 5879 goto out; 5880 } 5881 5882 btf_mod->sysfs_attr = attr; 5883 } 5884 5885 break; 5886 case MODULE_STATE_GOING: 5887 mutex_lock(&btf_module_mutex); 5888 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) { 5889 if (btf_mod->module != module) 5890 continue; 5891 5892 list_del(&btf_mod->list); 5893 if (btf_mod->sysfs_attr) 5894 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr); 5895 btf_put(btf_mod->btf); 5896 kfree(btf_mod->sysfs_attr); 5897 kfree(btf_mod); 5898 break; 5899 } 5900 mutex_unlock(&btf_module_mutex); 5901 break; 5902 } 5903 out: 5904 return notifier_from_errno(err); 5905 } 5906 5907 static struct notifier_block btf_module_nb = { 5908 .notifier_call = btf_module_notify, 5909 }; 5910 5911 static int __init btf_module_init(void) 5912 { 5913 register_module_notifier(&btf_module_nb); 5914 return 0; 5915 } 5916 5917 fs_initcall(btf_module_init); 5918 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */ 5919 5920 struct module *btf_try_get_module(const struct btf *btf) 5921 { 5922 struct module *res = NULL; 5923 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES 5924 struct btf_module *btf_mod, *tmp; 5925 5926 mutex_lock(&btf_module_mutex); 5927 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) { 5928 if (btf_mod->btf != btf) 5929 continue; 5930 5931 if (try_module_get(btf_mod->module)) 5932 res = btf_mod->module; 5933 5934 break; 5935 } 5936 mutex_unlock(&btf_module_mutex); 5937 #endif 5938 5939 return res; 5940 } 5941