1 /* Postprocess module symbol versions 2 * 3 * Copyright 2003 Kai Germaschewski 4 * Copyright 2002-2004 Rusty Russell, IBM Corporation 5 * Copyright 2006-2008 Sam Ravnborg 6 * Based in part on module-init-tools/depmod.c,file2alias 7 * 8 * This software may be used and distributed according to the terms 9 * of the GNU General Public License, incorporated herein by reference. 10 * 11 * Usage: modpost vmlinux module1.o module2.o ... 12 */ 13 14 #define _GNU_SOURCE 15 #include <elf.h> 16 #include <fnmatch.h> 17 #include <stdio.h> 18 #include <ctype.h> 19 #include <string.h> 20 #include <limits.h> 21 #include <stdbool.h> 22 #include <errno.h> 23 #include "modpost.h" 24 #include "../../include/linux/license.h" 25 26 /* Are we using CONFIG_MODVERSIONS? */ 27 static bool modversions; 28 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */ 29 static bool all_versions; 30 /* If we are modposting external module set to 1 */ 31 static bool external_module; 32 /* Only warn about unresolved symbols */ 33 static bool warn_unresolved; 34 35 static int sec_mismatch_count; 36 static bool sec_mismatch_warn_only = true; 37 /* ignore missing files */ 38 static bool ignore_missing_files; 39 /* If set to 1, only warn (instead of error) about missing ns imports */ 40 static bool allow_missing_ns_imports; 41 42 static bool error_occurred; 43 44 /* 45 * Cut off the warnings when there are too many. This typically occurs when 46 * vmlinux is missing. ('make modules' without building vmlinux.) 47 */ 48 #define MAX_UNRESOLVED_REPORTS 10 49 static unsigned int nr_unresolved; 50 51 /* In kernel, this size is defined in linux/module.h; 52 * here we use Elf_Addr instead of long for covering cross-compile 53 */ 54 55 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr)) 56 57 void __attribute__((format(printf, 2, 3))) 58 modpost_log(enum loglevel loglevel, const char *fmt, ...) 59 { 60 va_list arglist; 61 62 switch (loglevel) { 63 case LOG_WARN: 64 fprintf(stderr, "WARNING: "); 65 break; 66 case LOG_ERROR: 67 fprintf(stderr, "ERROR: "); 68 break; 69 case LOG_FATAL: 70 fprintf(stderr, "FATAL: "); 71 break; 72 default: /* invalid loglevel, ignore */ 73 break; 74 } 75 76 fprintf(stderr, "modpost: "); 77 78 va_start(arglist, fmt); 79 vfprintf(stderr, fmt, arglist); 80 va_end(arglist); 81 82 if (loglevel == LOG_FATAL) 83 exit(1); 84 if (loglevel == LOG_ERROR) 85 error_occurred = true; 86 } 87 88 static inline bool strends(const char *str, const char *postfix) 89 { 90 if (strlen(str) < strlen(postfix)) 91 return false; 92 93 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; 94 } 95 96 void *do_nofail(void *ptr, const char *expr) 97 { 98 if (!ptr) 99 fatal("Memory allocation failure: %s.\n", expr); 100 101 return ptr; 102 } 103 104 char *read_text_file(const char *filename) 105 { 106 struct stat st; 107 size_t nbytes; 108 int fd; 109 char *buf; 110 111 fd = open(filename, O_RDONLY); 112 if (fd < 0) { 113 perror(filename); 114 exit(1); 115 } 116 117 if (fstat(fd, &st) < 0) { 118 perror(filename); 119 exit(1); 120 } 121 122 buf = NOFAIL(malloc(st.st_size + 1)); 123 124 nbytes = st.st_size; 125 126 while (nbytes) { 127 ssize_t bytes_read; 128 129 bytes_read = read(fd, buf, nbytes); 130 if (bytes_read < 0) { 131 perror(filename); 132 exit(1); 133 } 134 135 nbytes -= bytes_read; 136 } 137 buf[st.st_size] = '\0'; 138 139 close(fd); 140 141 return buf; 142 } 143 144 char *get_line(char **stringp) 145 { 146 char *orig = *stringp, *next; 147 148 /* do not return the unwanted extra line at EOF */ 149 if (!orig || *orig == '\0') 150 return NULL; 151 152 /* don't use strsep here, it is not available everywhere */ 153 next = strchr(orig, '\n'); 154 if (next) 155 *next++ = '\0'; 156 157 *stringp = next; 158 159 return orig; 160 } 161 162 /* A list of all modules we processed */ 163 LIST_HEAD(modules); 164 165 static struct module *find_module(const char *modname) 166 { 167 struct module *mod; 168 169 list_for_each_entry(mod, &modules, list) { 170 if (strcmp(mod->name, modname) == 0) 171 return mod; 172 } 173 return NULL; 174 } 175 176 static struct module *new_module(const char *name, size_t namelen) 177 { 178 struct module *mod; 179 180 mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1)); 181 memset(mod, 0, sizeof(*mod)); 182 183 INIT_LIST_HEAD(&mod->exported_symbols); 184 INIT_LIST_HEAD(&mod->unresolved_symbols); 185 INIT_LIST_HEAD(&mod->missing_namespaces); 186 INIT_LIST_HEAD(&mod->imported_namespaces); 187 188 memcpy(mod->name, name, namelen); 189 mod->name[namelen] = '\0'; 190 mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0); 191 192 /* 193 * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE() 194 * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue 195 * modpost will exit wiht error anyway. 196 */ 197 mod->is_gpl_compatible = true; 198 199 list_add_tail(&mod->list, &modules); 200 201 return mod; 202 } 203 204 /* A hash of all exported symbols, 205 * struct symbol is also used for lists of unresolved symbols */ 206 207 #define SYMBOL_HASH_SIZE 1024 208 209 struct symbol { 210 struct symbol *next; 211 struct list_head list; /* link to module::exported_symbols or module::unresolved_symbols */ 212 struct module *module; 213 char *namespace; 214 unsigned int crc; 215 bool crc_valid; 216 bool weak; 217 bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */ 218 char name[]; 219 }; 220 221 static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; 222 223 /* This is based on the hash algorithm from gdbm, via tdb */ 224 static inline unsigned int tdb_hash(const char *name) 225 { 226 unsigned value; /* Used to compute the hash value. */ 227 unsigned i; /* Used to cycle through random values. */ 228 229 /* Set the initial value from the key size. */ 230 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++) 231 value = (value + (((unsigned char *)name)[i] << (i*5 % 24))); 232 233 return (1103515243 * value + 12345); 234 } 235 236 /** 237 * Allocate a new symbols for use in the hash of exported symbols or 238 * the list of unresolved symbols per module 239 **/ 240 static struct symbol *alloc_symbol(const char *name) 241 { 242 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); 243 244 memset(s, 0, sizeof(*s)); 245 strcpy(s->name, name); 246 247 return s; 248 } 249 250 /* For the hash of exported symbols */ 251 static void hash_add_symbol(struct symbol *sym) 252 { 253 unsigned int hash; 254 255 hash = tdb_hash(sym->name) % SYMBOL_HASH_SIZE; 256 sym->next = symbolhash[hash]; 257 symbolhash[hash] = sym; 258 } 259 260 static void sym_add_unresolved(const char *name, struct module *mod, bool weak) 261 { 262 struct symbol *sym; 263 264 sym = alloc_symbol(name); 265 sym->weak = weak; 266 267 list_add_tail(&sym->list, &mod->unresolved_symbols); 268 } 269 270 static struct symbol *sym_find_with_module(const char *name, struct module *mod) 271 { 272 struct symbol *s; 273 274 /* For our purposes, .foo matches foo. PPC64 needs this. */ 275 if (name[0] == '.') 276 name++; 277 278 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) { 279 if (strcmp(s->name, name) == 0 && (!mod || s->module == mod)) 280 return s; 281 } 282 return NULL; 283 } 284 285 static struct symbol *find_symbol(const char *name) 286 { 287 return sym_find_with_module(name, NULL); 288 } 289 290 struct namespace_list { 291 struct list_head list; 292 char namespace[]; 293 }; 294 295 static bool contains_namespace(struct list_head *head, const char *namespace) 296 { 297 struct namespace_list *list; 298 299 list_for_each_entry(list, head, list) { 300 if (!strcmp(list->namespace, namespace)) 301 return true; 302 } 303 304 return false; 305 } 306 307 static void add_namespace(struct list_head *head, const char *namespace) 308 { 309 struct namespace_list *ns_entry; 310 311 if (!contains_namespace(head, namespace)) { 312 ns_entry = NOFAIL(malloc(sizeof(*ns_entry) + 313 strlen(namespace) + 1)); 314 strcpy(ns_entry->namespace, namespace); 315 list_add_tail(&ns_entry->list, head); 316 } 317 } 318 319 static void *sym_get_data_by_offset(const struct elf_info *info, 320 unsigned int secindex, unsigned long offset) 321 { 322 Elf_Shdr *sechdr = &info->sechdrs[secindex]; 323 324 if (info->hdr->e_type != ET_REL) 325 offset -= sechdr->sh_addr; 326 327 return (void *)info->hdr + sechdr->sh_offset + offset; 328 } 329 330 static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym) 331 { 332 return sym_get_data_by_offset(info, get_secindex(info, sym), 333 sym->st_value); 334 } 335 336 static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr) 337 { 338 return sym_get_data_by_offset(info, info->secindex_strings, 339 sechdr->sh_name); 340 } 341 342 static const char *sec_name(const struct elf_info *info, int secindex) 343 { 344 return sech_name(info, &info->sechdrs[secindex]); 345 } 346 347 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) 348 349 static void sym_update_namespace(const char *symname, const char *namespace) 350 { 351 struct symbol *s = find_symbol(symname); 352 353 /* 354 * That symbol should have been created earlier and thus this is 355 * actually an assertion. 356 */ 357 if (!s) { 358 error("Could not update namespace(%s) for symbol %s\n", 359 namespace, symname); 360 return; 361 } 362 363 free(s->namespace); 364 s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; 365 } 366 367 static struct symbol *sym_add_exported(const char *name, struct module *mod, 368 bool gpl_only) 369 { 370 struct symbol *s = find_symbol(name); 371 372 if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) { 373 error("%s: '%s' exported twice. Previous export was in %s%s\n", 374 mod->name, name, s->module->name, 375 s->module->is_vmlinux ? "" : ".ko"); 376 } 377 378 s = alloc_symbol(name); 379 s->module = mod; 380 s->is_gpl_only = gpl_only; 381 list_add_tail(&s->list, &mod->exported_symbols); 382 hash_add_symbol(s); 383 384 return s; 385 } 386 387 static void sym_set_crc(struct symbol *sym, unsigned int crc) 388 { 389 sym->crc = crc; 390 sym->crc_valid = true; 391 } 392 393 static void *grab_file(const char *filename, size_t *size) 394 { 395 struct stat st; 396 void *map = MAP_FAILED; 397 int fd; 398 399 fd = open(filename, O_RDONLY); 400 if (fd < 0) 401 return NULL; 402 if (fstat(fd, &st)) 403 goto failed; 404 405 *size = st.st_size; 406 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 407 408 failed: 409 close(fd); 410 if (map == MAP_FAILED) 411 return NULL; 412 return map; 413 } 414 415 static void release_file(void *file, size_t size) 416 { 417 munmap(file, size); 418 } 419 420 static int parse_elf(struct elf_info *info, const char *filename) 421 { 422 unsigned int i; 423 Elf_Ehdr *hdr; 424 Elf_Shdr *sechdrs; 425 Elf_Sym *sym; 426 const char *secstrings; 427 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U; 428 429 hdr = grab_file(filename, &info->size); 430 if (!hdr) { 431 if (ignore_missing_files) { 432 fprintf(stderr, "%s: %s (ignored)\n", filename, 433 strerror(errno)); 434 return 0; 435 } 436 perror(filename); 437 exit(1); 438 } 439 info->hdr = hdr; 440 if (info->size < sizeof(*hdr)) { 441 /* file too small, assume this is an empty .o file */ 442 return 0; 443 } 444 /* Is this a valid ELF file? */ 445 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) || 446 (hdr->e_ident[EI_MAG1] != ELFMAG1) || 447 (hdr->e_ident[EI_MAG2] != ELFMAG2) || 448 (hdr->e_ident[EI_MAG3] != ELFMAG3)) { 449 /* Not an ELF file - silently ignore it */ 450 return 0; 451 } 452 /* Fix endianness in ELF header */ 453 hdr->e_type = TO_NATIVE(hdr->e_type); 454 hdr->e_machine = TO_NATIVE(hdr->e_machine); 455 hdr->e_version = TO_NATIVE(hdr->e_version); 456 hdr->e_entry = TO_NATIVE(hdr->e_entry); 457 hdr->e_phoff = TO_NATIVE(hdr->e_phoff); 458 hdr->e_shoff = TO_NATIVE(hdr->e_shoff); 459 hdr->e_flags = TO_NATIVE(hdr->e_flags); 460 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize); 461 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize); 462 hdr->e_phnum = TO_NATIVE(hdr->e_phnum); 463 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize); 464 hdr->e_shnum = TO_NATIVE(hdr->e_shnum); 465 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); 466 sechdrs = (void *)hdr + hdr->e_shoff; 467 info->sechdrs = sechdrs; 468 469 /* Check if file offset is correct */ 470 if (hdr->e_shoff > info->size) { 471 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n", 472 (unsigned long)hdr->e_shoff, filename, info->size); 473 return 0; 474 } 475 476 if (hdr->e_shnum == SHN_UNDEF) { 477 /* 478 * There are more than 64k sections, 479 * read count from .sh_size. 480 */ 481 info->num_sections = TO_NATIVE(sechdrs[0].sh_size); 482 } 483 else { 484 info->num_sections = hdr->e_shnum; 485 } 486 if (hdr->e_shstrndx == SHN_XINDEX) { 487 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link); 488 } 489 else { 490 info->secindex_strings = hdr->e_shstrndx; 491 } 492 493 /* Fix endianness in section headers */ 494 for (i = 0; i < info->num_sections; i++) { 495 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); 496 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); 497 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags); 498 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr); 499 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); 500 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); 501 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); 502 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info); 503 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign); 504 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize); 505 } 506 /* Find symbol table. */ 507 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset; 508 for (i = 1; i < info->num_sections; i++) { 509 const char *secname; 510 int nobits = sechdrs[i].sh_type == SHT_NOBITS; 511 512 if (!nobits && sechdrs[i].sh_offset > info->size) { 513 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > " 514 "sizeof(*hrd)=%zu\n", filename, 515 (unsigned long)sechdrs[i].sh_offset, 516 sizeof(*hdr)); 517 return 0; 518 } 519 secname = secstrings + sechdrs[i].sh_name; 520 if (strcmp(secname, ".modinfo") == 0) { 521 if (nobits) 522 fatal("%s has NOBITS .modinfo\n", filename); 523 info->modinfo = (void *)hdr + sechdrs[i].sh_offset; 524 info->modinfo_len = sechdrs[i].sh_size; 525 } 526 527 if (sechdrs[i].sh_type == SHT_SYMTAB) { 528 unsigned int sh_link_idx; 529 symtab_idx = i; 530 info->symtab_start = (void *)hdr + 531 sechdrs[i].sh_offset; 532 info->symtab_stop = (void *)hdr + 533 sechdrs[i].sh_offset + sechdrs[i].sh_size; 534 sh_link_idx = sechdrs[i].sh_link; 535 info->strtab = (void *)hdr + 536 sechdrs[sh_link_idx].sh_offset; 537 } 538 539 /* 32bit section no. table? ("more than 64k sections") */ 540 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) { 541 symtab_shndx_idx = i; 542 info->symtab_shndx_start = (void *)hdr + 543 sechdrs[i].sh_offset; 544 info->symtab_shndx_stop = (void *)hdr + 545 sechdrs[i].sh_offset + sechdrs[i].sh_size; 546 } 547 } 548 if (!info->symtab_start) 549 fatal("%s has no symtab?\n", filename); 550 551 /* Fix endianness in symbols */ 552 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) { 553 sym->st_shndx = TO_NATIVE(sym->st_shndx); 554 sym->st_name = TO_NATIVE(sym->st_name); 555 sym->st_value = TO_NATIVE(sym->st_value); 556 sym->st_size = TO_NATIVE(sym->st_size); 557 } 558 559 if (symtab_shndx_idx != ~0U) { 560 Elf32_Word *p; 561 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link) 562 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n", 563 filename, sechdrs[symtab_shndx_idx].sh_link, 564 symtab_idx); 565 /* Fix endianness */ 566 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop; 567 p++) 568 *p = TO_NATIVE(*p); 569 } 570 571 return 1; 572 } 573 574 static void parse_elf_finish(struct elf_info *info) 575 { 576 release_file(info->hdr, info->size); 577 } 578 579 static int ignore_undef_symbol(struct elf_info *info, const char *symname) 580 { 581 /* ignore __this_module, it will be resolved shortly */ 582 if (strcmp(symname, "__this_module") == 0) 583 return 1; 584 /* ignore global offset table */ 585 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) 586 return 1; 587 if (info->hdr->e_machine == EM_PPC) 588 /* Special register function linked on all modules during final link of .ko */ 589 if (strstarts(symname, "_restgpr_") || 590 strstarts(symname, "_savegpr_") || 591 strstarts(symname, "_rest32gpr_") || 592 strstarts(symname, "_save32gpr_") || 593 strstarts(symname, "_restvr_") || 594 strstarts(symname, "_savevr_")) 595 return 1; 596 if (info->hdr->e_machine == EM_PPC64) 597 /* Special register function linked on all modules during final link of .ko */ 598 if (strstarts(symname, "_restgpr0_") || 599 strstarts(symname, "_savegpr0_") || 600 strstarts(symname, "_restvr_") || 601 strstarts(symname, "_savevr_") || 602 strcmp(symname, ".TOC.") == 0) 603 return 1; 604 605 if (info->hdr->e_machine == EM_S390) 606 /* Expoline thunks are linked on all kernel modules during final link of .ko */ 607 if (strstarts(symname, "__s390_indirect_jump_r")) 608 return 1; 609 /* Do not ignore this symbol */ 610 return 0; 611 } 612 613 static void handle_symbol(struct module *mod, struct elf_info *info, 614 const Elf_Sym *sym, const char *symname) 615 { 616 switch (sym->st_shndx) { 617 case SHN_COMMON: 618 if (strstarts(symname, "__gnu_lto_")) { 619 /* Should warn here, but modpost runs before the linker */ 620 } else 621 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); 622 break; 623 case SHN_UNDEF: 624 /* undefined symbol */ 625 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && 626 ELF_ST_BIND(sym->st_info) != STB_WEAK) 627 break; 628 if (ignore_undef_symbol(info, symname)) 629 break; 630 if (info->hdr->e_machine == EM_SPARC || 631 info->hdr->e_machine == EM_SPARCV9) { 632 /* Ignore register directives. */ 633 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER) 634 break; 635 if (symname[0] == '.') { 636 char *munged = NOFAIL(strdup(symname)); 637 munged[0] = '_'; 638 munged[1] = toupper(munged[1]); 639 symname = munged; 640 } 641 } 642 643 sym_add_unresolved(symname, mod, 644 ELF_ST_BIND(sym->st_info) == STB_WEAK); 645 break; 646 default: 647 /* All exported symbols */ 648 if (strstarts(symname, "__ksymtab_")) { 649 const char *name, *secname; 650 651 name = symname + strlen("__ksymtab_"); 652 secname = sec_name(info, get_secindex(info, sym)); 653 654 if (strstarts(secname, "___ksymtab_gpl+")) 655 sym_add_exported(name, mod, true); 656 else if (strstarts(secname, "___ksymtab+")) 657 sym_add_exported(name, mod, false); 658 } 659 if (strcmp(symname, "init_module") == 0) 660 mod->has_init = true; 661 if (strcmp(symname, "cleanup_module") == 0) 662 mod->has_cleanup = true; 663 break; 664 } 665 } 666 667 /** 668 * Parse tag=value strings from .modinfo section 669 **/ 670 static char *next_string(char *string, unsigned long *secsize) 671 { 672 /* Skip non-zero chars */ 673 while (string[0]) { 674 string++; 675 if ((*secsize)-- <= 1) 676 return NULL; 677 } 678 679 /* Skip any zero padding. */ 680 while (!string[0]) { 681 string++; 682 if ((*secsize)-- <= 1) 683 return NULL; 684 } 685 return string; 686 } 687 688 static char *get_next_modinfo(struct elf_info *info, const char *tag, 689 char *prev) 690 { 691 char *p; 692 unsigned int taglen = strlen(tag); 693 char *modinfo = info->modinfo; 694 unsigned long size = info->modinfo_len; 695 696 if (prev) { 697 size -= prev - modinfo; 698 modinfo = next_string(prev, &size); 699 } 700 701 for (p = modinfo; p; p = next_string(p, &size)) { 702 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') 703 return p + taglen + 1; 704 } 705 return NULL; 706 } 707 708 static char *get_modinfo(struct elf_info *info, const char *tag) 709 710 { 711 return get_next_modinfo(info, tag, NULL); 712 } 713 714 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym) 715 { 716 if (sym) 717 return elf->strtab + sym->st_name; 718 else 719 return "(unknown)"; 720 } 721 722 /* 723 * Check whether the 'string' argument matches one of the 'patterns', 724 * an array of shell wildcard patterns (glob). 725 * 726 * Return true is there is a match. 727 */ 728 static bool match(const char *string, const char *const patterns[]) 729 { 730 const char *pattern; 731 732 while ((pattern = *patterns++)) { 733 if (!fnmatch(pattern, string, 0)) 734 return true; 735 } 736 737 return false; 738 } 739 740 /* sections that we do not want to do full section mismatch check on */ 741 static const char *const section_white_list[] = 742 { 743 ".comment*", 744 ".debug*", 745 ".cranges", /* sh64 */ 746 ".zdebug*", /* Compressed debug sections. */ 747 ".GCC.command.line", /* record-gcc-switches */ 748 ".mdebug*", /* alpha, score, mips etc. */ 749 ".pdr", /* alpha, score, mips etc. */ 750 ".stab*", 751 ".note*", 752 ".got*", 753 ".toc*", 754 ".xt.prop", /* xtensa */ 755 ".xt.lit", /* xtensa */ 756 ".arcextmap*", /* arc */ 757 ".gnu.linkonce.arcext*", /* arc : modules */ 758 ".cmem*", /* EZchip */ 759 ".fmt_slot*", /* EZchip */ 760 ".gnu.lto*", 761 ".discard.*", 762 NULL 763 }; 764 765 /* 766 * This is used to find sections missing the SHF_ALLOC flag. 767 * The cause of this is often a section specified in assembler 768 * without "ax" / "aw". 769 */ 770 static void check_section(const char *modname, struct elf_info *elf, 771 Elf_Shdr *sechdr) 772 { 773 const char *sec = sech_name(elf, sechdr); 774 775 if (sechdr->sh_type == SHT_PROGBITS && 776 !(sechdr->sh_flags & SHF_ALLOC) && 777 !match(sec, section_white_list)) { 778 warn("%s (%s): unexpected non-allocatable section.\n" 779 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n" 780 "Note that for example <linux/init.h> contains\n" 781 "section definitions for use in .S files.\n\n", 782 modname, sec); 783 } 784 } 785 786 787 788 #define ALL_INIT_DATA_SECTIONS \ 789 ".init.setup", ".init.rodata", ".meminit.rodata", \ 790 ".init.data", ".meminit.data" 791 #define ALL_EXIT_DATA_SECTIONS \ 792 ".exit.data", ".memexit.data" 793 794 #define ALL_INIT_TEXT_SECTIONS \ 795 ".init.text", ".meminit.text" 796 #define ALL_EXIT_TEXT_SECTIONS \ 797 ".exit.text", ".memexit.text" 798 799 #define ALL_PCI_INIT_SECTIONS \ 800 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \ 801 ".pci_fixup_enable", ".pci_fixup_resume", \ 802 ".pci_fixup_resume_early", ".pci_fixup_suspend" 803 804 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS 805 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS 806 807 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS 808 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS 809 810 #define DATA_SECTIONS ".data", ".data.rel" 811 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ 812 ".kprobes.text", ".cpuidle.text", ".noinstr.text" 813 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ 814 ".fixup", ".entry.text", ".exception.text", ".text.*", \ 815 ".coldtext", ".softirqentry.text" 816 817 #define INIT_SECTIONS ".init.*" 818 #define MEM_INIT_SECTIONS ".meminit.*" 819 820 #define EXIT_SECTIONS ".exit.*" 821 #define MEM_EXIT_SECTIONS ".memexit.*" 822 823 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \ 824 TEXT_SECTIONS, OTHER_TEXT_SECTIONS 825 826 /* init data sections */ 827 static const char *const init_data_sections[] = 828 { ALL_INIT_DATA_SECTIONS, NULL }; 829 830 /* all init sections */ 831 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL }; 832 833 /* All init and exit sections (code + data) */ 834 static const char *const init_exit_sections[] = 835 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }; 836 837 /* all text sections */ 838 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL }; 839 840 /* data section */ 841 static const char *const data_sections[] = { DATA_SECTIONS, NULL }; 842 843 844 /* symbols in .data that may refer to init/exit sections */ 845 #define DEFAULT_SYMBOL_WHITE_LIST \ 846 "*driver", \ 847 "*_template", /* scsi uses *_template a lot */ \ 848 "*_timer", /* arm uses ops structures named _timer a lot */ \ 849 "*_sht", /* scsi also used *_sht to some extent */ \ 850 "*_ops", \ 851 "*_probe", \ 852 "*_probe_one", \ 853 "*_console" 854 855 static const char *const head_sections[] = { ".head.text*", NULL }; 856 static const char *const linker_symbols[] = 857 { "__init_begin", "_sinittext", "_einittext", NULL }; 858 static const char *const optim_symbols[] = { "*.constprop.*", NULL }; 859 860 enum mismatch { 861 TEXT_TO_ANY_INIT, 862 DATA_TO_ANY_INIT, 863 TEXT_TO_ANY_EXIT, 864 DATA_TO_ANY_EXIT, 865 XXXINIT_TO_SOME_INIT, 866 XXXEXIT_TO_SOME_EXIT, 867 ANY_INIT_TO_ANY_EXIT, 868 ANY_EXIT_TO_ANY_INIT, 869 EXPORT_TO_INIT_EXIT, 870 EXTABLE_TO_NON_TEXT, 871 }; 872 873 /** 874 * Describe how to match sections on different criteria: 875 * 876 * @fromsec: Array of sections to be matched. 877 * 878 * @bad_tosec: Relocations applied to a section in @fromsec to a section in 879 * this array is forbidden (black-list). Can be empty. 880 * 881 * @good_tosec: Relocations applied to a section in @fromsec must be 882 * targeting sections in this array (white-list). Can be empty. 883 * 884 * @mismatch: Type of mismatch. 885 * 886 * @symbol_white_list: Do not match a relocation to a symbol in this list 887 * even if it is targeting a section in @bad_to_sec. 888 * 889 * @handler: Specific handler to call when a match is found. If NULL, 890 * default_mismatch_handler() will be called. 891 * 892 */ 893 struct sectioncheck { 894 const char *fromsec[20]; 895 const char *bad_tosec[20]; 896 const char *good_tosec[20]; 897 enum mismatch mismatch; 898 const char *symbol_white_list[20]; 899 void (*handler)(const char *modname, struct elf_info *elf, 900 const struct sectioncheck* const mismatch, 901 Elf_Rela *r, Elf_Sym *sym, const char *fromsec); 902 903 }; 904 905 static void extable_mismatch_handler(const char *modname, struct elf_info *elf, 906 const struct sectioncheck* const mismatch, 907 Elf_Rela *r, Elf_Sym *sym, 908 const char *fromsec); 909 910 static const struct sectioncheck sectioncheck[] = { 911 /* Do not reference init/exit code/data from 912 * normal code and data 913 */ 914 { 915 .fromsec = { TEXT_SECTIONS, NULL }, 916 .bad_tosec = { ALL_INIT_SECTIONS, NULL }, 917 .mismatch = TEXT_TO_ANY_INIT, 918 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 919 }, 920 { 921 .fromsec = { DATA_SECTIONS, NULL }, 922 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, 923 .mismatch = DATA_TO_ANY_INIT, 924 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 925 }, 926 { 927 .fromsec = { DATA_SECTIONS, NULL }, 928 .bad_tosec = { INIT_SECTIONS, NULL }, 929 .mismatch = DATA_TO_ANY_INIT, 930 .symbol_white_list = { 931 "*_template", "*_timer", "*_sht", "*_ops", 932 "*_probe", "*_probe_one", "*_console", NULL 933 }, 934 }, 935 { 936 .fromsec = { TEXT_SECTIONS, NULL }, 937 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 938 .mismatch = TEXT_TO_ANY_EXIT, 939 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 940 }, 941 { 942 .fromsec = { DATA_SECTIONS, NULL }, 943 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 944 .mismatch = DATA_TO_ANY_EXIT, 945 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 946 }, 947 /* Do not reference init code/data from meminit code/data */ 948 { 949 .fromsec = { ALL_XXXINIT_SECTIONS, NULL }, 950 .bad_tosec = { INIT_SECTIONS, NULL }, 951 .mismatch = XXXINIT_TO_SOME_INIT, 952 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 953 }, 954 /* Do not reference exit code/data from memexit code/data */ 955 { 956 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL }, 957 .bad_tosec = { EXIT_SECTIONS, NULL }, 958 .mismatch = XXXEXIT_TO_SOME_EXIT, 959 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 960 }, 961 /* Do not use exit code/data from init code */ 962 { 963 .fromsec = { ALL_INIT_SECTIONS, NULL }, 964 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 965 .mismatch = ANY_INIT_TO_ANY_EXIT, 966 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 967 }, 968 /* Do not use init code/data from exit code */ 969 { 970 .fromsec = { ALL_EXIT_SECTIONS, NULL }, 971 .bad_tosec = { ALL_INIT_SECTIONS, NULL }, 972 .mismatch = ANY_EXIT_TO_ANY_INIT, 973 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 974 }, 975 { 976 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL }, 977 .bad_tosec = { INIT_SECTIONS, NULL }, 978 .mismatch = ANY_INIT_TO_ANY_EXIT, 979 .symbol_white_list = { NULL }, 980 }, 981 /* Do not export init/exit functions or data */ 982 { 983 .fromsec = { "__ksymtab*", NULL }, 984 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, 985 .mismatch = EXPORT_TO_INIT_EXIT, 986 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 987 }, 988 { 989 .fromsec = { "__ex_table", NULL }, 990 /* If you're adding any new black-listed sections in here, consider 991 * adding a special 'printer' for them in scripts/check_extable. 992 */ 993 .bad_tosec = { ".altinstr_replacement", NULL }, 994 .good_tosec = {ALL_TEXT_SECTIONS , NULL}, 995 .mismatch = EXTABLE_TO_NON_TEXT, 996 .handler = extable_mismatch_handler, 997 } 998 }; 999 1000 static const struct sectioncheck *section_mismatch( 1001 const char *fromsec, const char *tosec) 1002 { 1003 int i; 1004 1005 /* 1006 * The target section could be the SHT_NUL section when we're 1007 * handling relocations to un-resolved symbols, trying to match it 1008 * doesn't make much sense and causes build failures on parisc 1009 * architectures. 1010 */ 1011 if (*tosec == '\0') 1012 return NULL; 1013 1014 for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) { 1015 const struct sectioncheck *check = §ioncheck[i]; 1016 1017 if (match(fromsec, check->fromsec)) { 1018 if (check->bad_tosec[0] && match(tosec, check->bad_tosec)) 1019 return check; 1020 if (check->good_tosec[0] && !match(tosec, check->good_tosec)) 1021 return check; 1022 } 1023 } 1024 return NULL; 1025 } 1026 1027 /** 1028 * Whitelist to allow certain references to pass with no warning. 1029 * 1030 * Pattern 1: 1031 * If a module parameter is declared __initdata and permissions=0 1032 * then this is legal despite the warning generated. 1033 * We cannot see value of permissions here, so just ignore 1034 * this pattern. 1035 * The pattern is identified by: 1036 * tosec = .init.data 1037 * fromsec = .data* 1038 * atsym =__param* 1039 * 1040 * Pattern 1a: 1041 * module_param_call() ops can refer to __init set function if permissions=0 1042 * The pattern is identified by: 1043 * tosec = .init.text 1044 * fromsec = .data* 1045 * atsym = __param_ops_* 1046 * 1047 * Pattern 2: 1048 * Many drivers utilise a *driver container with references to 1049 * add, remove, probe functions etc. 1050 * the pattern is identified by: 1051 * tosec = init or exit section 1052 * fromsec = data section 1053 * atsym = *driver, *_template, *_sht, *_ops, *_probe, 1054 * *probe_one, *_console, *_timer 1055 * 1056 * Pattern 3: 1057 * Whitelist all references from .head.text to any init section 1058 * 1059 * Pattern 4: 1060 * Some symbols belong to init section but still it is ok to reference 1061 * these from non-init sections as these symbols don't have any memory 1062 * allocated for them and symbol address and value are same. So even 1063 * if init section is freed, its ok to reference those symbols. 1064 * For ex. symbols marking the init section boundaries. 1065 * This pattern is identified by 1066 * refsymname = __init_begin, _sinittext, _einittext 1067 * 1068 * Pattern 5: 1069 * GCC may optimize static inlines when fed constant arg(s) resulting 1070 * in functions like cpumask_empty() -- generating an associated symbol 1071 * cpumask_empty.constprop.3 that appears in the audit. If the const that 1072 * is passed in comes from __init, like say nmi_ipi_mask, we get a 1073 * meaningless section warning. May need to add isra symbols too... 1074 * This pattern is identified by 1075 * tosec = init section 1076 * fromsec = text section 1077 * refsymname = *.constprop.* 1078 * 1079 * Pattern 6: 1080 * Hide section mismatch warnings for ELF local symbols. The goal 1081 * is to eliminate false positive modpost warnings caused by 1082 * compiler-generated ELF local symbol names such as ".LANCHOR1". 1083 * Autogenerated symbol names bypass modpost's "Pattern 2" 1084 * whitelisting, which relies on pattern-matching against symbol 1085 * names to work. (One situation where gcc can autogenerate ELF 1086 * local symbols is when "-fsection-anchors" is used.) 1087 **/ 1088 static int secref_whitelist(const struct sectioncheck *mismatch, 1089 const char *fromsec, const char *fromsym, 1090 const char *tosec, const char *tosym) 1091 { 1092 /* Check for pattern 1 */ 1093 if (match(tosec, init_data_sections) && 1094 match(fromsec, data_sections) && 1095 strstarts(fromsym, "__param")) 1096 return 0; 1097 1098 /* Check for pattern 1a */ 1099 if (strcmp(tosec, ".init.text") == 0 && 1100 match(fromsec, data_sections) && 1101 strstarts(fromsym, "__param_ops_")) 1102 return 0; 1103 1104 /* Check for pattern 2 */ 1105 if (match(tosec, init_exit_sections) && 1106 match(fromsec, data_sections) && 1107 match(fromsym, mismatch->symbol_white_list)) 1108 return 0; 1109 1110 /* Check for pattern 3 */ 1111 if (match(fromsec, head_sections) && 1112 match(tosec, init_sections)) 1113 return 0; 1114 1115 /* Check for pattern 4 */ 1116 if (match(tosym, linker_symbols)) 1117 return 0; 1118 1119 /* Check for pattern 5 */ 1120 if (match(fromsec, text_sections) && 1121 match(tosec, init_sections) && 1122 match(fromsym, optim_symbols)) 1123 return 0; 1124 1125 /* Check for pattern 6 */ 1126 if (strstarts(fromsym, ".L")) 1127 return 0; 1128 1129 return 1; 1130 } 1131 1132 static inline int is_arm_mapping_symbol(const char *str) 1133 { 1134 return str[0] == '$' && 1135 (str[1] == 'a' || str[1] == 'd' || str[1] == 't' || str[1] == 'x') 1136 && (str[2] == '\0' || str[2] == '.'); 1137 } 1138 1139 /* 1140 * If there's no name there, ignore it; likewise, ignore it if it's 1141 * one of the magic symbols emitted used by current ARM tools. 1142 * 1143 * Otherwise if find_symbols_between() returns those symbols, they'll 1144 * fail the whitelist tests and cause lots of false alarms ... fixable 1145 * only by merging __exit and __init sections into __text, bloating 1146 * the kernel (which is especially evil on embedded platforms). 1147 */ 1148 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) 1149 { 1150 const char *name = elf->strtab + sym->st_name; 1151 1152 if (!name || !strlen(name)) 1153 return 0; 1154 return !is_arm_mapping_symbol(name); 1155 } 1156 1157 /** 1158 * Find symbol based on relocation record info. 1159 * In some cases the symbol supplied is a valid symbol so 1160 * return refsym. If st_name != 0 we assume this is a valid symbol. 1161 * In other cases the symbol needs to be looked up in the symbol table 1162 * based on section and address. 1163 * **/ 1164 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, 1165 Elf_Sym *relsym) 1166 { 1167 Elf_Sym *sym; 1168 Elf_Sym *near = NULL; 1169 Elf64_Sword distance = 20; 1170 Elf64_Sword d; 1171 unsigned int relsym_secindex; 1172 1173 if (relsym->st_name != 0) 1174 return relsym; 1175 1176 relsym_secindex = get_secindex(elf, relsym); 1177 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1178 if (get_secindex(elf, sym) != relsym_secindex) 1179 continue; 1180 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) 1181 continue; 1182 if (!is_valid_name(elf, sym)) 1183 continue; 1184 if (sym->st_value == addr) 1185 return sym; 1186 /* Find a symbol nearby - addr are maybe negative */ 1187 d = sym->st_value - addr; 1188 if (d < 0) 1189 d = addr - sym->st_value; 1190 if (d < distance) { 1191 distance = d; 1192 near = sym; 1193 } 1194 } 1195 /* We need a close match */ 1196 if (distance < 20) 1197 return near; 1198 else 1199 return NULL; 1200 } 1201 1202 /* 1203 * Find symbols before or equal addr and after addr - in the section sec. 1204 * If we find two symbols with equal offset prefer one with a valid name. 1205 * The ELF format may have a better way to detect what type of symbol 1206 * it is, but this works for now. 1207 **/ 1208 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, 1209 const char *sec) 1210 { 1211 Elf_Sym *sym; 1212 Elf_Sym *near = NULL; 1213 Elf_Addr distance = ~0; 1214 1215 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1216 const char *symsec; 1217 1218 if (is_shndx_special(sym->st_shndx)) 1219 continue; 1220 symsec = sec_name(elf, get_secindex(elf, sym)); 1221 if (strcmp(symsec, sec) != 0) 1222 continue; 1223 if (!is_valid_name(elf, sym)) 1224 continue; 1225 if (sym->st_value <= addr && addr - sym->st_value <= distance) { 1226 distance = addr - sym->st_value; 1227 near = sym; 1228 } 1229 } 1230 return near; 1231 } 1232 1233 /* 1234 * Convert a section name to the function/data attribute 1235 * .init.text => __init 1236 * .memexitconst => __memconst 1237 * etc. 1238 * 1239 * The memory of returned value has been allocated on a heap. The user of this 1240 * method should free it after usage. 1241 */ 1242 static char *sec2annotation(const char *s) 1243 { 1244 if (match(s, init_exit_sections)) { 1245 char *p = NOFAIL(malloc(20)); 1246 char *r = p; 1247 1248 *p++ = '_'; 1249 *p++ = '_'; 1250 if (*s == '.') 1251 s++; 1252 while (*s && *s != '.') 1253 *p++ = *s++; 1254 *p = '\0'; 1255 if (*s == '.') 1256 s++; 1257 if (strstr(s, "rodata") != NULL) 1258 strcat(p, "const "); 1259 else if (strstr(s, "data") != NULL) 1260 strcat(p, "data "); 1261 else 1262 strcat(p, " "); 1263 return r; 1264 } else { 1265 return NOFAIL(strdup("")); 1266 } 1267 } 1268 1269 static int is_function(Elf_Sym *sym) 1270 { 1271 if (sym) 1272 return ELF_ST_TYPE(sym->st_info) == STT_FUNC; 1273 else 1274 return -1; 1275 } 1276 1277 static void print_section_list(const char * const list[20]) 1278 { 1279 const char *const *s = list; 1280 1281 while (*s) { 1282 fprintf(stderr, "%s", *s); 1283 s++; 1284 if (*s) 1285 fprintf(stderr, ", "); 1286 } 1287 fprintf(stderr, "\n"); 1288 } 1289 1290 static inline void get_pretty_name(int is_func, const char** name, const char** name_p) 1291 { 1292 switch (is_func) { 1293 case 0: *name = "variable"; *name_p = ""; break; 1294 case 1: *name = "function"; *name_p = "()"; break; 1295 default: *name = "(unknown reference)"; *name_p = ""; break; 1296 } 1297 } 1298 1299 /* 1300 * Print a warning about a section mismatch. 1301 * Try to find symbols near it so user can find it. 1302 * Check whitelist before warning - it may be a false positive. 1303 */ 1304 static void report_sec_mismatch(const char *modname, 1305 const struct sectioncheck *mismatch, 1306 const char *fromsec, 1307 unsigned long long fromaddr, 1308 const char *fromsym, 1309 int from_is_func, 1310 const char *tosec, const char *tosym, 1311 int to_is_func) 1312 { 1313 const char *from, *from_p; 1314 const char *to, *to_p; 1315 char *prl_from; 1316 char *prl_to; 1317 1318 sec_mismatch_count++; 1319 1320 get_pretty_name(from_is_func, &from, &from_p); 1321 get_pretty_name(to_is_func, &to, &to_p); 1322 1323 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s " 1324 "to the %s %s:%s%s\n", 1325 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec, 1326 tosym, to_p); 1327 1328 switch (mismatch->mismatch) { 1329 case TEXT_TO_ANY_INIT: 1330 prl_from = sec2annotation(fromsec); 1331 prl_to = sec2annotation(tosec); 1332 fprintf(stderr, 1333 "The function %s%s() references\n" 1334 "the %s %s%s%s.\n" 1335 "This is often because %s lacks a %s\n" 1336 "annotation or the annotation of %s is wrong.\n", 1337 prl_from, fromsym, 1338 to, prl_to, tosym, to_p, 1339 fromsym, prl_to, tosym); 1340 free(prl_from); 1341 free(prl_to); 1342 break; 1343 case DATA_TO_ANY_INIT: { 1344 prl_to = sec2annotation(tosec); 1345 fprintf(stderr, 1346 "The variable %s references\n" 1347 "the %s %s%s%s\n" 1348 "If the reference is valid then annotate the\n" 1349 "variable with __init* or __refdata (see linux/init.h) " 1350 "or name the variable:\n", 1351 fromsym, to, prl_to, tosym, to_p); 1352 print_section_list(mismatch->symbol_white_list); 1353 free(prl_to); 1354 break; 1355 } 1356 case TEXT_TO_ANY_EXIT: 1357 prl_to = sec2annotation(tosec); 1358 fprintf(stderr, 1359 "The function %s() references a %s in an exit section.\n" 1360 "Often the %s %s%s has valid usage outside the exit section\n" 1361 "and the fix is to remove the %sannotation of %s.\n", 1362 fromsym, to, to, tosym, to_p, prl_to, tosym); 1363 free(prl_to); 1364 break; 1365 case DATA_TO_ANY_EXIT: { 1366 prl_to = sec2annotation(tosec); 1367 fprintf(stderr, 1368 "The variable %s references\n" 1369 "the %s %s%s%s\n" 1370 "If the reference is valid then annotate the\n" 1371 "variable with __exit* (see linux/init.h) or " 1372 "name the variable:\n", 1373 fromsym, to, prl_to, tosym, to_p); 1374 print_section_list(mismatch->symbol_white_list); 1375 free(prl_to); 1376 break; 1377 } 1378 case XXXINIT_TO_SOME_INIT: 1379 case XXXEXIT_TO_SOME_EXIT: 1380 prl_from = sec2annotation(fromsec); 1381 prl_to = sec2annotation(tosec); 1382 fprintf(stderr, 1383 "The %s %s%s%s references\n" 1384 "a %s %s%s%s.\n" 1385 "If %s is only used by %s then\n" 1386 "annotate %s with a matching annotation.\n", 1387 from, prl_from, fromsym, from_p, 1388 to, prl_to, tosym, to_p, 1389 tosym, fromsym, tosym); 1390 free(prl_from); 1391 free(prl_to); 1392 break; 1393 case ANY_INIT_TO_ANY_EXIT: 1394 prl_from = sec2annotation(fromsec); 1395 prl_to = sec2annotation(tosec); 1396 fprintf(stderr, 1397 "The %s %s%s%s references\n" 1398 "a %s %s%s%s.\n" 1399 "This is often seen when error handling " 1400 "in the init function\n" 1401 "uses functionality in the exit path.\n" 1402 "The fix is often to remove the %sannotation of\n" 1403 "%s%s so it may be used outside an exit section.\n", 1404 from, prl_from, fromsym, from_p, 1405 to, prl_to, tosym, to_p, 1406 prl_to, tosym, to_p); 1407 free(prl_from); 1408 free(prl_to); 1409 break; 1410 case ANY_EXIT_TO_ANY_INIT: 1411 prl_from = sec2annotation(fromsec); 1412 prl_to = sec2annotation(tosec); 1413 fprintf(stderr, 1414 "The %s %s%s%s references\n" 1415 "a %s %s%s%s.\n" 1416 "This is often seen when error handling " 1417 "in the exit function\n" 1418 "uses functionality in the init path.\n" 1419 "The fix is often to remove the %sannotation of\n" 1420 "%s%s so it may be used outside an init section.\n", 1421 from, prl_from, fromsym, from_p, 1422 to, prl_to, tosym, to_p, 1423 prl_to, tosym, to_p); 1424 free(prl_from); 1425 free(prl_to); 1426 break; 1427 case EXPORT_TO_INIT_EXIT: 1428 prl_to = sec2annotation(tosec); 1429 fprintf(stderr, 1430 "The symbol %s is exported and annotated %s\n" 1431 "Fix this by removing the %sannotation of %s " 1432 "or drop the export.\n", 1433 tosym, prl_to, prl_to, tosym); 1434 free(prl_to); 1435 break; 1436 case EXTABLE_TO_NON_TEXT: 1437 fatal("There's a special handler for this mismatch type, " 1438 "we should never get here."); 1439 break; 1440 } 1441 fprintf(stderr, "\n"); 1442 } 1443 1444 static void default_mismatch_handler(const char *modname, struct elf_info *elf, 1445 const struct sectioncheck* const mismatch, 1446 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1447 { 1448 const char *tosec; 1449 Elf_Sym *to; 1450 Elf_Sym *from; 1451 const char *tosym; 1452 const char *fromsym; 1453 1454 from = find_elf_symbol2(elf, r->r_offset, fromsec); 1455 fromsym = sym_name(elf, from); 1456 1457 if (strstarts(fromsym, "reference___initcall")) 1458 return; 1459 1460 tosec = sec_name(elf, get_secindex(elf, sym)); 1461 to = find_elf_symbol(elf, r->r_addend, sym); 1462 tosym = sym_name(elf, to); 1463 1464 /* check whitelist - we may ignore it */ 1465 if (secref_whitelist(mismatch, 1466 fromsec, fromsym, tosec, tosym)) { 1467 report_sec_mismatch(modname, mismatch, 1468 fromsec, r->r_offset, fromsym, 1469 is_function(from), tosec, tosym, 1470 is_function(to)); 1471 } 1472 } 1473 1474 static int is_executable_section(struct elf_info* elf, unsigned int section_index) 1475 { 1476 if (section_index > elf->num_sections) 1477 fatal("section_index is outside elf->num_sections!\n"); 1478 1479 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); 1480 } 1481 1482 /* 1483 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size() 1484 * to know the sizeof(struct exception_table_entry) for the target architecture. 1485 */ 1486 static unsigned int extable_entry_size = 0; 1487 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) 1488 { 1489 /* 1490 * If we're currently checking the second relocation within __ex_table, 1491 * that relocation offset tells us the offsetof(struct 1492 * exception_table_entry, fixup) which is equal to sizeof(struct 1493 * exception_table_entry) divided by two. We use that to our advantage 1494 * since there's no portable way to get that size as every architecture 1495 * seems to go with different sized types. Not pretty but better than 1496 * hard-coding the size for every architecture.. 1497 */ 1498 if (!extable_entry_size) 1499 extable_entry_size = r->r_offset * 2; 1500 } 1501 1502 static inline bool is_extable_fault_address(Elf_Rela *r) 1503 { 1504 /* 1505 * extable_entry_size is only discovered after we've handled the 1506 * _second_ relocation in __ex_table, so only abort when we're not 1507 * handling the first reloc and extable_entry_size is zero. 1508 */ 1509 if (r->r_offset && extable_entry_size == 0) 1510 fatal("extable_entry size hasn't been discovered!\n"); 1511 1512 return ((r->r_offset == 0) || 1513 (r->r_offset % extable_entry_size == 0)); 1514 } 1515 1516 #define is_second_extable_reloc(Start, Cur, Sec) \ 1517 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) 1518 1519 static void report_extable_warnings(const char* modname, struct elf_info* elf, 1520 const struct sectioncheck* const mismatch, 1521 Elf_Rela* r, Elf_Sym* sym, 1522 const char* fromsec, const char* tosec) 1523 { 1524 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec); 1525 const char* fromsym_name = sym_name(elf, fromsym); 1526 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); 1527 const char* tosym_name = sym_name(elf, tosym); 1528 const char* from_pretty_name; 1529 const char* from_pretty_name_p; 1530 const char* to_pretty_name; 1531 const char* to_pretty_name_p; 1532 1533 get_pretty_name(is_function(fromsym), 1534 &from_pretty_name, &from_pretty_name_p); 1535 get_pretty_name(is_function(tosym), 1536 &to_pretty_name, &to_pretty_name_p); 1537 1538 warn("%s(%s+0x%lx): Section mismatch in reference" 1539 " from the %s %s%s to the %s %s:%s%s\n", 1540 modname, fromsec, (long)r->r_offset, from_pretty_name, 1541 fromsym_name, from_pretty_name_p, 1542 to_pretty_name, tosec, tosym_name, to_pretty_name_p); 1543 1544 if (!match(tosec, mismatch->bad_tosec) && 1545 is_executable_section(elf, get_secindex(elf, sym))) 1546 fprintf(stderr, 1547 "The relocation at %s+0x%lx references\n" 1548 "section \"%s\" which is not in the list of\n" 1549 "authorized sections. If you're adding a new section\n" 1550 "and/or if this reference is valid, add \"%s\" to the\n" 1551 "list of authorized sections to jump to on fault.\n" 1552 "This can be achieved by adding \"%s\" to \n" 1553 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", 1554 fromsec, (long)r->r_offset, tosec, tosec, tosec); 1555 } 1556 1557 static void extable_mismatch_handler(const char* modname, struct elf_info *elf, 1558 const struct sectioncheck* const mismatch, 1559 Elf_Rela* r, Elf_Sym* sym, 1560 const char *fromsec) 1561 { 1562 const char* tosec = sec_name(elf, get_secindex(elf, sym)); 1563 1564 sec_mismatch_count++; 1565 1566 report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec); 1567 1568 if (match(tosec, mismatch->bad_tosec)) 1569 fatal("The relocation at %s+0x%lx references\n" 1570 "section \"%s\" which is black-listed.\n" 1571 "Something is seriously wrong and should be fixed.\n" 1572 "You might get more information about where this is\n" 1573 "coming from by using scripts/check_extable.sh %s\n", 1574 fromsec, (long)r->r_offset, tosec, modname); 1575 else if (!is_executable_section(elf, get_secindex(elf, sym))) { 1576 if (is_extable_fault_address(r)) 1577 fatal("The relocation at %s+0x%lx references\n" 1578 "section \"%s\" which is not executable, IOW\n" 1579 "it is not possible for the kernel to fault\n" 1580 "at that address. Something is seriously wrong\n" 1581 "and should be fixed.\n", 1582 fromsec, (long)r->r_offset, tosec); 1583 else 1584 fatal("The relocation at %s+0x%lx references\n" 1585 "section \"%s\" which is not executable, IOW\n" 1586 "the kernel will fault if it ever tries to\n" 1587 "jump to it. Something is seriously wrong\n" 1588 "and should be fixed.\n", 1589 fromsec, (long)r->r_offset, tosec); 1590 } 1591 } 1592 1593 static void check_section_mismatch(const char *modname, struct elf_info *elf, 1594 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1595 { 1596 const char *tosec = sec_name(elf, get_secindex(elf, sym)); 1597 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); 1598 1599 if (mismatch) { 1600 if (mismatch->handler) 1601 mismatch->handler(modname, elf, mismatch, 1602 r, sym, fromsec); 1603 else 1604 default_mismatch_handler(modname, elf, mismatch, 1605 r, sym, fromsec); 1606 } 1607 } 1608 1609 static unsigned int *reloc_location(struct elf_info *elf, 1610 Elf_Shdr *sechdr, Elf_Rela *r) 1611 { 1612 return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset); 1613 } 1614 1615 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1616 { 1617 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1618 unsigned int *location = reloc_location(elf, sechdr, r); 1619 1620 switch (r_typ) { 1621 case R_386_32: 1622 r->r_addend = TO_NATIVE(*location); 1623 break; 1624 case R_386_PC32: 1625 r->r_addend = TO_NATIVE(*location) + 4; 1626 /* For CONFIG_RELOCATABLE=y */ 1627 if (elf->hdr->e_type == ET_EXEC) 1628 r->r_addend += r->r_offset; 1629 break; 1630 } 1631 return 0; 1632 } 1633 1634 #ifndef R_ARM_CALL 1635 #define R_ARM_CALL 28 1636 #endif 1637 #ifndef R_ARM_JUMP24 1638 #define R_ARM_JUMP24 29 1639 #endif 1640 1641 #ifndef R_ARM_THM_CALL 1642 #define R_ARM_THM_CALL 10 1643 #endif 1644 #ifndef R_ARM_THM_JUMP24 1645 #define R_ARM_THM_JUMP24 30 1646 #endif 1647 #ifndef R_ARM_THM_JUMP19 1648 #define R_ARM_THM_JUMP19 51 1649 #endif 1650 1651 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1652 { 1653 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1654 1655 switch (r_typ) { 1656 case R_ARM_ABS32: 1657 /* From ARM ABI: (S + A) | T */ 1658 r->r_addend = (int)(long) 1659 (elf->symtab_start + ELF_R_SYM(r->r_info)); 1660 break; 1661 case R_ARM_PC24: 1662 case R_ARM_CALL: 1663 case R_ARM_JUMP24: 1664 case R_ARM_THM_CALL: 1665 case R_ARM_THM_JUMP24: 1666 case R_ARM_THM_JUMP19: 1667 /* From ARM ABI: ((S + A) | T) - P */ 1668 r->r_addend = (int)(long)(elf->hdr + 1669 sechdr->sh_offset + 1670 (r->r_offset - sechdr->sh_addr)); 1671 break; 1672 default: 1673 return 1; 1674 } 1675 return 0; 1676 } 1677 1678 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1679 { 1680 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1681 unsigned int *location = reloc_location(elf, sechdr, r); 1682 unsigned int inst; 1683 1684 if (r_typ == R_MIPS_HI16) 1685 return 1; /* skip this */ 1686 inst = TO_NATIVE(*location); 1687 switch (r_typ) { 1688 case R_MIPS_LO16: 1689 r->r_addend = inst & 0xffff; 1690 break; 1691 case R_MIPS_26: 1692 r->r_addend = (inst & 0x03ffffff) << 2; 1693 break; 1694 case R_MIPS_32: 1695 r->r_addend = inst; 1696 break; 1697 } 1698 return 0; 1699 } 1700 1701 #ifndef EM_RISCV 1702 #define EM_RISCV 243 1703 #endif 1704 1705 #ifndef R_RISCV_SUB32 1706 #define R_RISCV_SUB32 39 1707 #endif 1708 1709 static void section_rela(const char *modname, struct elf_info *elf, 1710 Elf_Shdr *sechdr) 1711 { 1712 Elf_Sym *sym; 1713 Elf_Rela *rela; 1714 Elf_Rela r; 1715 unsigned int r_sym; 1716 const char *fromsec; 1717 1718 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; 1719 Elf_Rela *stop = (void *)start + sechdr->sh_size; 1720 1721 fromsec = sech_name(elf, sechdr); 1722 fromsec += strlen(".rela"); 1723 /* if from section (name) is know good then skip it */ 1724 if (match(fromsec, section_white_list)) 1725 return; 1726 1727 for (rela = start; rela < stop; rela++) { 1728 r.r_offset = TO_NATIVE(rela->r_offset); 1729 #if KERNEL_ELFCLASS == ELFCLASS64 1730 if (elf->hdr->e_machine == EM_MIPS) { 1731 unsigned int r_typ; 1732 r_sym = ELF64_MIPS_R_SYM(rela->r_info); 1733 r_sym = TO_NATIVE(r_sym); 1734 r_typ = ELF64_MIPS_R_TYPE(rela->r_info); 1735 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1736 } else { 1737 r.r_info = TO_NATIVE(rela->r_info); 1738 r_sym = ELF_R_SYM(r.r_info); 1739 } 1740 #else 1741 r.r_info = TO_NATIVE(rela->r_info); 1742 r_sym = ELF_R_SYM(r.r_info); 1743 #endif 1744 r.r_addend = TO_NATIVE(rela->r_addend); 1745 switch (elf->hdr->e_machine) { 1746 case EM_RISCV: 1747 if (!strcmp("__ex_table", fromsec) && 1748 ELF_R_TYPE(r.r_info) == R_RISCV_SUB32) 1749 continue; 1750 break; 1751 } 1752 sym = elf->symtab_start + r_sym; 1753 /* Skip special sections */ 1754 if (is_shndx_special(sym->st_shndx)) 1755 continue; 1756 if (is_second_extable_reloc(start, rela, fromsec)) 1757 find_extable_entry_size(fromsec, &r); 1758 check_section_mismatch(modname, elf, &r, sym, fromsec); 1759 } 1760 } 1761 1762 static void section_rel(const char *modname, struct elf_info *elf, 1763 Elf_Shdr *sechdr) 1764 { 1765 Elf_Sym *sym; 1766 Elf_Rel *rel; 1767 Elf_Rela r; 1768 unsigned int r_sym; 1769 const char *fromsec; 1770 1771 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; 1772 Elf_Rel *stop = (void *)start + sechdr->sh_size; 1773 1774 fromsec = sech_name(elf, sechdr); 1775 fromsec += strlen(".rel"); 1776 /* if from section (name) is know good then skip it */ 1777 if (match(fromsec, section_white_list)) 1778 return; 1779 1780 for (rel = start; rel < stop; rel++) { 1781 r.r_offset = TO_NATIVE(rel->r_offset); 1782 #if KERNEL_ELFCLASS == ELFCLASS64 1783 if (elf->hdr->e_machine == EM_MIPS) { 1784 unsigned int r_typ; 1785 r_sym = ELF64_MIPS_R_SYM(rel->r_info); 1786 r_sym = TO_NATIVE(r_sym); 1787 r_typ = ELF64_MIPS_R_TYPE(rel->r_info); 1788 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1789 } else { 1790 r.r_info = TO_NATIVE(rel->r_info); 1791 r_sym = ELF_R_SYM(r.r_info); 1792 } 1793 #else 1794 r.r_info = TO_NATIVE(rel->r_info); 1795 r_sym = ELF_R_SYM(r.r_info); 1796 #endif 1797 r.r_addend = 0; 1798 switch (elf->hdr->e_machine) { 1799 case EM_386: 1800 if (addend_386_rel(elf, sechdr, &r)) 1801 continue; 1802 break; 1803 case EM_ARM: 1804 if (addend_arm_rel(elf, sechdr, &r)) 1805 continue; 1806 break; 1807 case EM_MIPS: 1808 if (addend_mips_rel(elf, sechdr, &r)) 1809 continue; 1810 break; 1811 } 1812 sym = elf->symtab_start + r_sym; 1813 /* Skip special sections */ 1814 if (is_shndx_special(sym->st_shndx)) 1815 continue; 1816 if (is_second_extable_reloc(start, rel, fromsec)) 1817 find_extable_entry_size(fromsec, &r); 1818 check_section_mismatch(modname, elf, &r, sym, fromsec); 1819 } 1820 } 1821 1822 /** 1823 * A module includes a number of sections that are discarded 1824 * either when loaded or when used as built-in. 1825 * For loaded modules all functions marked __init and all data 1826 * marked __initdata will be discarded when the module has been initialized. 1827 * Likewise for modules used built-in the sections marked __exit 1828 * are discarded because __exit marked function are supposed to be called 1829 * only when a module is unloaded which never happens for built-in modules. 1830 * The check_sec_ref() function traverses all relocation records 1831 * to find all references to a section that reference a section that will 1832 * be discarded and warns about it. 1833 **/ 1834 static void check_sec_ref(const char *modname, struct elf_info *elf) 1835 { 1836 int i; 1837 Elf_Shdr *sechdrs = elf->sechdrs; 1838 1839 /* Walk through all sections */ 1840 for (i = 0; i < elf->num_sections; i++) { 1841 check_section(modname, elf, &elf->sechdrs[i]); 1842 /* We want to process only relocation sections and not .init */ 1843 if (sechdrs[i].sh_type == SHT_RELA) 1844 section_rela(modname, elf, &elf->sechdrs[i]); 1845 else if (sechdrs[i].sh_type == SHT_REL) 1846 section_rel(modname, elf, &elf->sechdrs[i]); 1847 } 1848 } 1849 1850 static char *remove_dot(char *s) 1851 { 1852 size_t n = strcspn(s, "."); 1853 1854 if (n && s[n]) { 1855 size_t m = strspn(s + n + 1, "0123456789"); 1856 if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0)) 1857 s[n] = 0; 1858 } 1859 return s; 1860 } 1861 1862 /* 1863 * The CRCs are recorded in .*.cmd files in the form of: 1864 * #SYMVER <name> <crc> 1865 */ 1866 static void extract_crcs_for_object(const char *object, struct module *mod) 1867 { 1868 char cmd_file[PATH_MAX]; 1869 char *buf, *p; 1870 const char *base; 1871 int dirlen, ret; 1872 1873 base = strrchr(object, '/'); 1874 if (base) { 1875 base++; 1876 dirlen = base - object; 1877 } else { 1878 dirlen = 0; 1879 base = object; 1880 } 1881 1882 ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd", 1883 dirlen, object, base); 1884 if (ret >= sizeof(cmd_file)) { 1885 error("%s: too long path was truncated\n", cmd_file); 1886 return; 1887 } 1888 1889 buf = read_text_file(cmd_file); 1890 p = buf; 1891 1892 while ((p = strstr(p, "\n#SYMVER "))) { 1893 char *name; 1894 size_t namelen; 1895 unsigned int crc; 1896 struct symbol *sym; 1897 1898 name = p + strlen("\n#SYMVER "); 1899 1900 p = strchr(name, ' '); 1901 if (!p) 1902 break; 1903 1904 namelen = p - name; 1905 p++; 1906 1907 if (!isdigit(*p)) 1908 continue; /* skip this line */ 1909 1910 crc = strtol(p, &p, 0); 1911 if (*p != '\n') 1912 continue; /* skip this line */ 1913 1914 name[namelen] = '\0'; 1915 1916 /* 1917 * sym_find_with_module() may return NULL here. 1918 * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y. 1919 * Since commit e1327a127703, genksyms calculates CRCs of all 1920 * symbols, including trimmed ones. Ignore orphan CRCs. 1921 */ 1922 sym = sym_find_with_module(name, mod); 1923 if (sym) 1924 sym_set_crc(sym, crc); 1925 } 1926 1927 free(buf); 1928 } 1929 1930 /* 1931 * The symbol versions (CRC) are recorded in the .*.cmd files. 1932 * Parse them to retrieve CRCs for the current module. 1933 */ 1934 static void mod_set_crcs(struct module *mod) 1935 { 1936 char objlist[PATH_MAX]; 1937 char *buf, *p, *obj; 1938 int ret; 1939 1940 if (mod->is_vmlinux) { 1941 strcpy(objlist, ".vmlinux.objs"); 1942 } else { 1943 /* objects for a module are listed in the *.mod file. */ 1944 ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name); 1945 if (ret >= sizeof(objlist)) { 1946 error("%s: too long path was truncated\n", objlist); 1947 return; 1948 } 1949 } 1950 1951 buf = read_text_file(objlist); 1952 p = buf; 1953 1954 while ((obj = strsep(&p, "\n")) && obj[0]) 1955 extract_crcs_for_object(obj, mod); 1956 1957 free(buf); 1958 } 1959 1960 static void read_symbols(const char *modname) 1961 { 1962 const char *symname; 1963 char *version; 1964 char *license; 1965 char *namespace; 1966 struct module *mod; 1967 struct elf_info info = { }; 1968 Elf_Sym *sym; 1969 1970 if (!parse_elf(&info, modname)) 1971 return; 1972 1973 if (!strends(modname, ".o")) { 1974 error("%s: filename must be suffixed with .o\n", modname); 1975 return; 1976 } 1977 1978 /* strip trailing .o */ 1979 mod = new_module(modname, strlen(modname) - strlen(".o")); 1980 1981 if (!mod->is_vmlinux) { 1982 license = get_modinfo(&info, "license"); 1983 if (!license) 1984 error("missing MODULE_LICENSE() in %s\n", modname); 1985 while (license) { 1986 if (!license_is_gpl_compatible(license)) { 1987 mod->is_gpl_compatible = false; 1988 break; 1989 } 1990 license = get_next_modinfo(&info, "license", license); 1991 } 1992 1993 namespace = get_modinfo(&info, "import_ns"); 1994 while (namespace) { 1995 add_namespace(&mod->imported_namespaces, namespace); 1996 namespace = get_next_modinfo(&info, "import_ns", 1997 namespace); 1998 } 1999 } 2000 2001 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 2002 symname = remove_dot(info.strtab + sym->st_name); 2003 2004 handle_symbol(mod, &info, sym, symname); 2005 handle_moddevtable(mod, &info, sym, symname); 2006 } 2007 2008 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 2009 symname = remove_dot(info.strtab + sym->st_name); 2010 2011 /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */ 2012 if (strstarts(symname, "__kstrtabns_")) 2013 sym_update_namespace(symname + strlen("__kstrtabns_"), 2014 sym_get_data(&info, sym)); 2015 } 2016 2017 check_sec_ref(modname, &info); 2018 2019 if (!mod->is_vmlinux) { 2020 version = get_modinfo(&info, "version"); 2021 if (version || all_versions) 2022 get_src_version(mod->name, mod->srcversion, 2023 sizeof(mod->srcversion) - 1); 2024 } 2025 2026 parse_elf_finish(&info); 2027 2028 if (modversions) { 2029 /* 2030 * Our trick to get versioning for module struct etc. - it's 2031 * never passed as an argument to an exported function, so 2032 * the automatic versioning doesn't pick it up, but it's really 2033 * important anyhow. 2034 */ 2035 sym_add_unresolved("module_layout", mod, false); 2036 2037 mod_set_crcs(mod); 2038 } 2039 } 2040 2041 static void read_symbols_from_files(const char *filename) 2042 { 2043 FILE *in = stdin; 2044 char fname[PATH_MAX]; 2045 2046 if (strcmp(filename, "-") != 0) { 2047 in = fopen(filename, "r"); 2048 if (!in) 2049 fatal("Can't open filenames file %s: %m", filename); 2050 } 2051 2052 while (fgets(fname, PATH_MAX, in) != NULL) { 2053 if (strends(fname, "\n")) 2054 fname[strlen(fname)-1] = '\0'; 2055 read_symbols(fname); 2056 } 2057 2058 if (in != stdin) 2059 fclose(in); 2060 } 2061 2062 #define SZ 500 2063 2064 /* We first write the generated file into memory using the 2065 * following helper, then compare to the file on disk and 2066 * only update the later if anything changed */ 2067 2068 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, 2069 const char *fmt, ...) 2070 { 2071 char tmp[SZ]; 2072 int len; 2073 va_list ap; 2074 2075 va_start(ap, fmt); 2076 len = vsnprintf(tmp, SZ, fmt, ap); 2077 buf_write(buf, tmp, len); 2078 va_end(ap); 2079 } 2080 2081 void buf_write(struct buffer *buf, const char *s, int len) 2082 { 2083 if (buf->size - buf->pos < len) { 2084 buf->size += len + SZ; 2085 buf->p = NOFAIL(realloc(buf->p, buf->size)); 2086 } 2087 strncpy(buf->p + buf->pos, s, len); 2088 buf->pos += len; 2089 } 2090 2091 static void check_exports(struct module *mod) 2092 { 2093 struct symbol *s, *exp; 2094 2095 list_for_each_entry(s, &mod->unresolved_symbols, list) { 2096 const char *basename; 2097 exp = find_symbol(s->name); 2098 if (!exp) { 2099 if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS) 2100 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR, 2101 "\"%s\" [%s.ko] undefined!\n", 2102 s->name, mod->name); 2103 continue; 2104 } 2105 if (exp->module == mod) { 2106 error("\"%s\" [%s.ko] was exported without definition\n", 2107 s->name, mod->name); 2108 continue; 2109 } 2110 2111 s->module = exp->module; 2112 s->crc_valid = exp->crc_valid; 2113 s->crc = exp->crc; 2114 2115 basename = strrchr(mod->name, '/'); 2116 if (basename) 2117 basename++; 2118 else 2119 basename = mod->name; 2120 2121 if (exp->namespace && 2122 !contains_namespace(&mod->imported_namespaces, exp->namespace)) { 2123 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR, 2124 "module %s uses symbol %s from namespace %s, but does not import it.\n", 2125 basename, exp->name, exp->namespace); 2126 add_namespace(&mod->missing_namespaces, exp->namespace); 2127 } 2128 2129 if (!mod->is_gpl_compatible && exp->is_gpl_only) 2130 error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n", 2131 basename, exp->name); 2132 } 2133 } 2134 2135 static void check_modname_len(struct module *mod) 2136 { 2137 const char *mod_name; 2138 2139 mod_name = strrchr(mod->name, '/'); 2140 if (mod_name == NULL) 2141 mod_name = mod->name; 2142 else 2143 mod_name++; 2144 if (strlen(mod_name) >= MODULE_NAME_LEN) 2145 error("module name is too long [%s.ko]\n", mod->name); 2146 } 2147 2148 /** 2149 * Header for the generated file 2150 **/ 2151 static void add_header(struct buffer *b, struct module *mod) 2152 { 2153 buf_printf(b, "#include <linux/module.h>\n"); 2154 /* 2155 * Include build-salt.h after module.h in order to 2156 * inherit the definitions. 2157 */ 2158 buf_printf(b, "#define INCLUDE_VERMAGIC\n"); 2159 buf_printf(b, "#include <linux/build-salt.h>\n"); 2160 buf_printf(b, "#include <linux/elfnote-lto.h>\n"); 2161 buf_printf(b, "#include <linux/export-internal.h>\n"); 2162 buf_printf(b, "#include <linux/vermagic.h>\n"); 2163 buf_printf(b, "#include <linux/compiler.h>\n"); 2164 buf_printf(b, "\n"); 2165 buf_printf(b, "BUILD_SALT;\n"); 2166 buf_printf(b, "BUILD_LTO_INFO;\n"); 2167 buf_printf(b, "\n"); 2168 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); 2169 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n"); 2170 buf_printf(b, "\n"); 2171 buf_printf(b, "__visible struct module __this_module\n"); 2172 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n"); 2173 buf_printf(b, "\t.name = KBUILD_MODNAME,\n"); 2174 if (mod->has_init) 2175 buf_printf(b, "\t.init = init_module,\n"); 2176 if (mod->has_cleanup) 2177 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" 2178 "\t.exit = cleanup_module,\n" 2179 "#endif\n"); 2180 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n"); 2181 buf_printf(b, "};\n"); 2182 2183 if (!external_module) 2184 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); 2185 2186 buf_printf(b, 2187 "\n" 2188 "#ifdef CONFIG_RETPOLINE\n" 2189 "MODULE_INFO(retpoline, \"Y\");\n" 2190 "#endif\n"); 2191 2192 if (strstarts(mod->name, "drivers/staging")) 2193 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); 2194 } 2195 2196 static void add_exported_symbols(struct buffer *buf, struct module *mod) 2197 { 2198 struct symbol *sym; 2199 2200 if (!modversions) 2201 return; 2202 2203 /* record CRCs for exported symbols */ 2204 buf_printf(buf, "\n"); 2205 list_for_each_entry(sym, &mod->exported_symbols, list) { 2206 if (!sym->crc_valid) { 2207 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n" 2208 "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n", 2209 sym->name, mod->name, mod->is_vmlinux ? "" : ".ko", 2210 sym->name); 2211 continue; 2212 } 2213 2214 buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n", 2215 sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : ""); 2216 } 2217 } 2218 2219 /** 2220 * Record CRCs for unresolved symbols 2221 **/ 2222 static void add_versions(struct buffer *b, struct module *mod) 2223 { 2224 struct symbol *s; 2225 2226 if (!modversions) 2227 return; 2228 2229 buf_printf(b, "\n"); 2230 buf_printf(b, "static const struct modversion_info ____versions[]\n"); 2231 buf_printf(b, "__used __section(\"__versions\") = {\n"); 2232 2233 list_for_each_entry(s, &mod->unresolved_symbols, list) { 2234 if (!s->module) 2235 continue; 2236 if (!s->crc_valid) { 2237 warn("\"%s\" [%s.ko] has no CRC!\n", 2238 s->name, mod->name); 2239 continue; 2240 } 2241 if (strlen(s->name) >= MODULE_NAME_LEN) { 2242 error("too long symbol \"%s\" [%s.ko]\n", 2243 s->name, mod->name); 2244 break; 2245 } 2246 buf_printf(b, "\t{ %#8x, \"%s\" },\n", 2247 s->crc, s->name); 2248 } 2249 2250 buf_printf(b, "};\n"); 2251 } 2252 2253 static void add_depends(struct buffer *b, struct module *mod) 2254 { 2255 struct symbol *s; 2256 int first = 1; 2257 2258 /* Clear ->seen flag of modules that own symbols needed by this. */ 2259 list_for_each_entry(s, &mod->unresolved_symbols, list) { 2260 if (s->module) 2261 s->module->seen = s->module->is_vmlinux; 2262 } 2263 2264 buf_printf(b, "\n"); 2265 buf_printf(b, "MODULE_INFO(depends, \""); 2266 list_for_each_entry(s, &mod->unresolved_symbols, list) { 2267 const char *p; 2268 if (!s->module) 2269 continue; 2270 2271 if (s->module->seen) 2272 continue; 2273 2274 s->module->seen = true; 2275 p = strrchr(s->module->name, '/'); 2276 if (p) 2277 p++; 2278 else 2279 p = s->module->name; 2280 buf_printf(b, "%s%s", first ? "" : ",", p); 2281 first = 0; 2282 } 2283 buf_printf(b, "\");\n"); 2284 } 2285 2286 static void add_srcversion(struct buffer *b, struct module *mod) 2287 { 2288 if (mod->srcversion[0]) { 2289 buf_printf(b, "\n"); 2290 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", 2291 mod->srcversion); 2292 } 2293 } 2294 2295 static void write_buf(struct buffer *b, const char *fname) 2296 { 2297 FILE *file; 2298 2299 if (error_occurred) 2300 return; 2301 2302 file = fopen(fname, "w"); 2303 if (!file) { 2304 perror(fname); 2305 exit(1); 2306 } 2307 if (fwrite(b->p, 1, b->pos, file) != b->pos) { 2308 perror(fname); 2309 exit(1); 2310 } 2311 if (fclose(file) != 0) { 2312 perror(fname); 2313 exit(1); 2314 } 2315 } 2316 2317 static void write_if_changed(struct buffer *b, const char *fname) 2318 { 2319 char *tmp; 2320 FILE *file; 2321 struct stat st; 2322 2323 file = fopen(fname, "r"); 2324 if (!file) 2325 goto write; 2326 2327 if (fstat(fileno(file), &st) < 0) 2328 goto close_write; 2329 2330 if (st.st_size != b->pos) 2331 goto close_write; 2332 2333 tmp = NOFAIL(malloc(b->pos)); 2334 if (fread(tmp, 1, b->pos, file) != b->pos) 2335 goto free_write; 2336 2337 if (memcmp(tmp, b->p, b->pos) != 0) 2338 goto free_write; 2339 2340 free(tmp); 2341 fclose(file); 2342 return; 2343 2344 free_write: 2345 free(tmp); 2346 close_write: 2347 fclose(file); 2348 write: 2349 write_buf(b, fname); 2350 } 2351 2352 static void write_vmlinux_export_c_file(struct module *mod) 2353 { 2354 struct buffer buf = { }; 2355 2356 buf_printf(&buf, 2357 "#include <linux/export-internal.h>\n"); 2358 2359 add_exported_symbols(&buf, mod); 2360 write_if_changed(&buf, ".vmlinux.export.c"); 2361 free(buf.p); 2362 } 2363 2364 /* do sanity checks, and generate *.mod.c file */ 2365 static void write_mod_c_file(struct module *mod) 2366 { 2367 struct buffer buf = { }; 2368 char fname[PATH_MAX]; 2369 int ret; 2370 2371 check_modname_len(mod); 2372 check_exports(mod); 2373 2374 add_header(&buf, mod); 2375 add_exported_symbols(&buf, mod); 2376 add_versions(&buf, mod); 2377 add_depends(&buf, mod); 2378 add_moddevtable(&buf, mod); 2379 add_srcversion(&buf, mod); 2380 2381 ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name); 2382 if (ret >= sizeof(fname)) { 2383 error("%s: too long path was truncated\n", fname); 2384 goto free; 2385 } 2386 2387 write_if_changed(&buf, fname); 2388 2389 free: 2390 free(buf.p); 2391 } 2392 2393 /* parse Module.symvers file. line format: 2394 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace 2395 **/ 2396 static void read_dump(const char *fname) 2397 { 2398 char *buf, *pos, *line; 2399 2400 buf = read_text_file(fname); 2401 if (!buf) 2402 /* No symbol versions, silently ignore */ 2403 return; 2404 2405 pos = buf; 2406 2407 while ((line = get_line(&pos))) { 2408 char *symname, *namespace, *modname, *d, *export; 2409 unsigned int crc; 2410 struct module *mod; 2411 struct symbol *s; 2412 bool gpl_only; 2413 2414 if (!(symname = strchr(line, '\t'))) 2415 goto fail; 2416 *symname++ = '\0'; 2417 if (!(modname = strchr(symname, '\t'))) 2418 goto fail; 2419 *modname++ = '\0'; 2420 if (!(export = strchr(modname, '\t'))) 2421 goto fail; 2422 *export++ = '\0'; 2423 if (!(namespace = strchr(export, '\t'))) 2424 goto fail; 2425 *namespace++ = '\0'; 2426 2427 crc = strtoul(line, &d, 16); 2428 if (*symname == '\0' || *modname == '\0' || *d != '\0') 2429 goto fail; 2430 2431 if (!strcmp(export, "EXPORT_SYMBOL_GPL")) { 2432 gpl_only = true; 2433 } else if (!strcmp(export, "EXPORT_SYMBOL")) { 2434 gpl_only = false; 2435 } else { 2436 error("%s: unknown license %s. skip", symname, export); 2437 continue; 2438 } 2439 2440 mod = find_module(modname); 2441 if (!mod) { 2442 mod = new_module(modname, strlen(modname)); 2443 mod->from_dump = true; 2444 } 2445 s = sym_add_exported(symname, mod, gpl_only); 2446 sym_set_crc(s, crc); 2447 sym_update_namespace(symname, namespace); 2448 } 2449 free(buf); 2450 return; 2451 fail: 2452 free(buf); 2453 fatal("parse error in symbol dump file\n"); 2454 } 2455 2456 static void write_dump(const char *fname) 2457 { 2458 struct buffer buf = { }; 2459 struct module *mod; 2460 struct symbol *sym; 2461 2462 list_for_each_entry(mod, &modules, list) { 2463 if (mod->from_dump) 2464 continue; 2465 list_for_each_entry(sym, &mod->exported_symbols, list) { 2466 buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n", 2467 sym->crc, sym->name, mod->name, 2468 sym->is_gpl_only ? "_GPL" : "", 2469 sym->namespace ?: ""); 2470 } 2471 } 2472 write_buf(&buf, fname); 2473 free(buf.p); 2474 } 2475 2476 static void write_namespace_deps_files(const char *fname) 2477 { 2478 struct module *mod; 2479 struct namespace_list *ns; 2480 struct buffer ns_deps_buf = {}; 2481 2482 list_for_each_entry(mod, &modules, list) { 2483 2484 if (mod->from_dump || list_empty(&mod->missing_namespaces)) 2485 continue; 2486 2487 buf_printf(&ns_deps_buf, "%s.ko:", mod->name); 2488 2489 list_for_each_entry(ns, &mod->missing_namespaces, list) 2490 buf_printf(&ns_deps_buf, " %s", ns->namespace); 2491 2492 buf_printf(&ns_deps_buf, "\n"); 2493 } 2494 2495 write_if_changed(&ns_deps_buf, fname); 2496 free(ns_deps_buf.p); 2497 } 2498 2499 struct dump_list { 2500 struct list_head list; 2501 const char *file; 2502 }; 2503 2504 int main(int argc, char **argv) 2505 { 2506 struct module *mod; 2507 char *missing_namespace_deps = NULL; 2508 char *dump_write = NULL, *files_source = NULL; 2509 int opt; 2510 LIST_HEAD(dump_lists); 2511 struct dump_list *dl, *dl2; 2512 2513 while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) { 2514 switch (opt) { 2515 case 'e': 2516 external_module = true; 2517 break; 2518 case 'i': 2519 dl = NOFAIL(malloc(sizeof(*dl))); 2520 dl->file = optarg; 2521 list_add_tail(&dl->list, &dump_lists); 2522 break; 2523 case 'm': 2524 modversions = true; 2525 break; 2526 case 'n': 2527 ignore_missing_files = true; 2528 break; 2529 case 'o': 2530 dump_write = optarg; 2531 break; 2532 case 'a': 2533 all_versions = true; 2534 break; 2535 case 'T': 2536 files_source = optarg; 2537 break; 2538 case 'w': 2539 warn_unresolved = true; 2540 break; 2541 case 'E': 2542 sec_mismatch_warn_only = false; 2543 break; 2544 case 'N': 2545 allow_missing_ns_imports = true; 2546 break; 2547 case 'd': 2548 missing_namespace_deps = optarg; 2549 break; 2550 default: 2551 exit(1); 2552 } 2553 } 2554 2555 list_for_each_entry_safe(dl, dl2, &dump_lists, list) { 2556 read_dump(dl->file); 2557 list_del(&dl->list); 2558 free(dl); 2559 } 2560 2561 while (optind < argc) 2562 read_symbols(argv[optind++]); 2563 2564 if (files_source) 2565 read_symbols_from_files(files_source); 2566 2567 list_for_each_entry(mod, &modules, list) { 2568 if (mod->from_dump) 2569 continue; 2570 2571 if (mod->is_vmlinux) 2572 write_vmlinux_export_c_file(mod); 2573 else 2574 write_mod_c_file(mod); 2575 } 2576 2577 if (missing_namespace_deps) 2578 write_namespace_deps_files(missing_namespace_deps); 2579 2580 if (dump_write) 2581 write_dump(dump_write); 2582 if (sec_mismatch_count && !sec_mismatch_warn_only) 2583 error("Section mismatches detected.\n" 2584 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); 2585 2586 if (nr_unresolved > MAX_UNRESOLVED_REPORTS) 2587 warn("suppressed %u unresolved symbol warnings because there were too many)\n", 2588 nr_unresolved - MAX_UNRESOLVED_REPORTS); 2589 2590 return error_occurred ? 1 : 0; 2591 } 2592