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 <stdio.h> 16 #include <ctype.h> 17 #include <string.h> 18 #include <limits.h> 19 #include <stdbool.h> 20 #include <errno.h> 21 #include "modpost.h" 22 #include "../../include/generated/autoconf.h" 23 #include "../../include/linux/license.h" 24 #include "../../include/linux/export.h" 25 26 /* Are we using CONFIG_MODVERSIONS? */ 27 static int modversions = 0; 28 /* Warn about undefined symbols? (do so if we have vmlinux) */ 29 static int have_vmlinux = 0; 30 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */ 31 static int all_versions = 0; 32 /* If we are modposting external module set to 1 */ 33 static int external_module = 0; 34 /* Warn about section mismatch in vmlinux if set to 1 */ 35 static int vmlinux_section_warnings = 1; 36 /* Only warn about unresolved symbols */ 37 static int warn_unresolved = 0; 38 /* How a symbol is exported */ 39 static int sec_mismatch_count = 0; 40 static int sec_mismatch_verbose = 1; 41 static int sec_mismatch_fatal = 0; 42 /* ignore missing files */ 43 static int ignore_missing_files; 44 45 enum export { 46 export_plain, export_unused, export_gpl, 47 export_unused_gpl, export_gpl_future, export_unknown 48 }; 49 50 /* In kernel, this size is defined in linux/module.h; 51 * here we use Elf_Addr instead of long for covering cross-compile 52 */ 53 54 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr)) 55 56 #define PRINTF __attribute__ ((format (printf, 1, 2))) 57 58 PRINTF void fatal(const char *fmt, ...) 59 { 60 va_list arglist; 61 62 fprintf(stderr, "FATAL: "); 63 64 va_start(arglist, fmt); 65 vfprintf(stderr, fmt, arglist); 66 va_end(arglist); 67 68 exit(1); 69 } 70 71 PRINTF void warn(const char *fmt, ...) 72 { 73 va_list arglist; 74 75 fprintf(stderr, "WARNING: "); 76 77 va_start(arglist, fmt); 78 vfprintf(stderr, fmt, arglist); 79 va_end(arglist); 80 } 81 82 PRINTF void merror(const char *fmt, ...) 83 { 84 va_list arglist; 85 86 fprintf(stderr, "ERROR: "); 87 88 va_start(arglist, fmt); 89 vfprintf(stderr, fmt, arglist); 90 va_end(arglist); 91 } 92 93 static inline bool strends(const char *str, const char *postfix) 94 { 95 if (strlen(str) < strlen(postfix)) 96 return false; 97 98 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; 99 } 100 101 static int is_vmlinux(const char *modname) 102 { 103 const char *myname; 104 105 myname = strrchr(modname, '/'); 106 if (myname) 107 myname++; 108 else 109 myname = modname; 110 111 return (strcmp(myname, "vmlinux") == 0) || 112 (strcmp(myname, "vmlinux.o") == 0); 113 } 114 115 void *do_nofail(void *ptr, const char *expr) 116 { 117 if (!ptr) 118 fatal("modpost: Memory allocation failure: %s.\n", expr); 119 120 return ptr; 121 } 122 123 /* A list of all modules we processed */ 124 static struct module *modules; 125 126 static struct module *find_module(char *modname) 127 { 128 struct module *mod; 129 130 for (mod = modules; mod; mod = mod->next) 131 if (strcmp(mod->name, modname) == 0) 132 break; 133 return mod; 134 } 135 136 static struct module *new_module(const char *modname) 137 { 138 struct module *mod; 139 char *p; 140 141 mod = NOFAIL(malloc(sizeof(*mod))); 142 memset(mod, 0, sizeof(*mod)); 143 p = NOFAIL(strdup(modname)); 144 145 /* strip trailing .o */ 146 if (strends(p, ".o")) { 147 p[strlen(p) - 2] = '\0'; 148 mod->is_dot_o = 1; 149 } 150 151 /* add to list */ 152 mod->name = p; 153 mod->gpl_compatible = -1; 154 mod->next = modules; 155 modules = mod; 156 157 return mod; 158 } 159 160 /* A hash of all exported symbols, 161 * struct symbol is also used for lists of unresolved symbols */ 162 163 #define SYMBOL_HASH_SIZE 1024 164 165 struct symbol { 166 struct symbol *next; 167 struct module *module; 168 unsigned int crc; 169 int crc_valid; 170 unsigned int weak:1; 171 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */ 172 unsigned int kernel:1; /* 1 if symbol is from kernel 173 * (only for external modules) **/ 174 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */ 175 enum export export; /* Type of export */ 176 char name[0]; 177 }; 178 179 static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; 180 181 /* This is based on the hash agorithm from gdbm, via tdb */ 182 static inline unsigned int tdb_hash(const char *name) 183 { 184 unsigned value; /* Used to compute the hash value. */ 185 unsigned i; /* Used to cycle through random values. */ 186 187 /* Set the initial value from the key size. */ 188 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++) 189 value = (value + (((unsigned char *)name)[i] << (i*5 % 24))); 190 191 return (1103515243 * value + 12345); 192 } 193 194 /** 195 * Allocate a new symbols for use in the hash of exported symbols or 196 * the list of unresolved symbols per module 197 **/ 198 static struct symbol *alloc_symbol(const char *name, unsigned int weak, 199 struct symbol *next) 200 { 201 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); 202 203 memset(s, 0, sizeof(*s)); 204 strcpy(s->name, name); 205 s->weak = weak; 206 s->next = next; 207 return s; 208 } 209 210 /* For the hash of exported symbols */ 211 static struct symbol *new_symbol(const char *name, struct module *module, 212 enum export export) 213 { 214 unsigned int hash; 215 struct symbol *new; 216 217 hash = tdb_hash(name) % SYMBOL_HASH_SIZE; 218 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]); 219 new->module = module; 220 new->export = export; 221 return new; 222 } 223 224 static struct symbol *find_symbol(const char *name) 225 { 226 struct symbol *s; 227 228 /* For our purposes, .foo matches foo. PPC64 needs this. */ 229 if (name[0] == '.') 230 name++; 231 232 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) { 233 if (strcmp(s->name, name) == 0) 234 return s; 235 } 236 return NULL; 237 } 238 239 static const struct { 240 const char *str; 241 enum export export; 242 } export_list[] = { 243 { .str = "EXPORT_SYMBOL", .export = export_plain }, 244 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused }, 245 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl }, 246 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl }, 247 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future }, 248 { .str = "(unknown)", .export = export_unknown }, 249 }; 250 251 252 static const char *export_str(enum export ex) 253 { 254 return export_list[ex].str; 255 } 256 257 static enum export export_no(const char *s) 258 { 259 int i; 260 261 if (!s) 262 return export_unknown; 263 for (i = 0; export_list[i].export != export_unknown; i++) { 264 if (strcmp(export_list[i].str, s) == 0) 265 return export_list[i].export; 266 } 267 return export_unknown; 268 } 269 270 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr) 271 { 272 return (void *)elf->hdr + 273 elf->sechdrs[elf->secindex_strings].sh_offset + 274 sechdr->sh_name; 275 } 276 277 static const char *sec_name(struct elf_info *elf, int secindex) 278 { 279 return sech_name(elf, &elf->sechdrs[secindex]); 280 } 281 282 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) 283 284 static enum export export_from_secname(struct elf_info *elf, unsigned int sec) 285 { 286 const char *secname = sec_name(elf, sec); 287 288 if (strstarts(secname, "___ksymtab+")) 289 return export_plain; 290 else if (strstarts(secname, "___ksymtab_unused+")) 291 return export_unused; 292 else if (strstarts(secname, "___ksymtab_gpl+")) 293 return export_gpl; 294 else if (strstarts(secname, "___ksymtab_unused_gpl+")) 295 return export_unused_gpl; 296 else if (strstarts(secname, "___ksymtab_gpl_future+")) 297 return export_gpl_future; 298 else 299 return export_unknown; 300 } 301 302 static enum export export_from_sec(struct elf_info *elf, unsigned int sec) 303 { 304 if (sec == elf->export_sec) 305 return export_plain; 306 else if (sec == elf->export_unused_sec) 307 return export_unused; 308 else if (sec == elf->export_gpl_sec) 309 return export_gpl; 310 else if (sec == elf->export_unused_gpl_sec) 311 return export_unused_gpl; 312 else if (sec == elf->export_gpl_future_sec) 313 return export_gpl_future; 314 else 315 return export_unknown; 316 } 317 318 /** 319 * Add an exported symbol - it may have already been added without a 320 * CRC, in this case just update the CRC 321 **/ 322 static struct symbol *sym_add_exported(const char *name, struct module *mod, 323 enum export export) 324 { 325 struct symbol *s = find_symbol(name); 326 327 if (!s) { 328 s = new_symbol(name, mod, export); 329 } else { 330 if (!s->preloaded) { 331 warn("%s: '%s' exported twice. Previous export " 332 "was in %s%s\n", mod->name, name, 333 s->module->name, 334 is_vmlinux(s->module->name) ?"":".ko"); 335 } else { 336 /* In case Module.symvers was out of date */ 337 s->module = mod; 338 } 339 } 340 s->preloaded = 0; 341 s->vmlinux = is_vmlinux(mod->name); 342 s->kernel = 0; 343 s->export = export; 344 return s; 345 } 346 347 static void sym_update_crc(const char *name, struct module *mod, 348 unsigned int crc, enum export export) 349 { 350 struct symbol *s = find_symbol(name); 351 352 if (!s) { 353 s = new_symbol(name, mod, export); 354 /* Don't complain when we find it later. */ 355 s->preloaded = 1; 356 } 357 s->crc = crc; 358 s->crc_valid = 1; 359 } 360 361 void *grab_file(const char *filename, unsigned long *size) 362 { 363 struct stat st; 364 void *map = MAP_FAILED; 365 int fd; 366 367 fd = open(filename, O_RDONLY); 368 if (fd < 0) 369 return NULL; 370 if (fstat(fd, &st)) 371 goto failed; 372 373 *size = st.st_size; 374 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 375 376 failed: 377 close(fd); 378 if (map == MAP_FAILED) 379 return NULL; 380 return map; 381 } 382 383 /** 384 * Return a copy of the next line in a mmap'ed file. 385 * spaces in the beginning of the line is trimmed away. 386 * Return a pointer to a static buffer. 387 **/ 388 char *get_next_line(unsigned long *pos, void *file, unsigned long size) 389 { 390 static char line[4096]; 391 int skip = 1; 392 size_t len = 0; 393 signed char *p = (signed char *)file + *pos; 394 char *s = line; 395 396 for (; *pos < size ; (*pos)++) { 397 if (skip && isspace(*p)) { 398 p++; 399 continue; 400 } 401 skip = 0; 402 if (*p != '\n' && (*pos < size)) { 403 len++; 404 *s++ = *p++; 405 if (len > 4095) 406 break; /* Too long, stop */ 407 } else { 408 /* End of string */ 409 *s = '\0'; 410 return line; 411 } 412 } 413 /* End of buffer */ 414 return NULL; 415 } 416 417 void release_file(void *file, unsigned long size) 418 { 419 munmap(file, size); 420 } 421 422 static int parse_elf(struct elf_info *info, const char *filename) 423 { 424 unsigned int i; 425 Elf_Ehdr *hdr; 426 Elf_Shdr *sechdrs; 427 Elf_Sym *sym; 428 const char *secstrings; 429 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U; 430 431 hdr = grab_file(filename, &info->size); 432 if (!hdr) { 433 if (ignore_missing_files) { 434 fprintf(stderr, "%s: %s (ignored)\n", filename, 435 strerror(errno)); 436 return 0; 437 } 438 perror(filename); 439 exit(1); 440 } 441 info->hdr = hdr; 442 if (info->size < sizeof(*hdr)) { 443 /* file too small, assume this is an empty .o file */ 444 return 0; 445 } 446 /* Is this a valid ELF file? */ 447 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) || 448 (hdr->e_ident[EI_MAG1] != ELFMAG1) || 449 (hdr->e_ident[EI_MAG2] != ELFMAG2) || 450 (hdr->e_ident[EI_MAG3] != ELFMAG3)) { 451 /* Not an ELF file - silently ignore it */ 452 return 0; 453 } 454 /* Fix endianness in ELF header */ 455 hdr->e_type = TO_NATIVE(hdr->e_type); 456 hdr->e_machine = TO_NATIVE(hdr->e_machine); 457 hdr->e_version = TO_NATIVE(hdr->e_version); 458 hdr->e_entry = TO_NATIVE(hdr->e_entry); 459 hdr->e_phoff = TO_NATIVE(hdr->e_phoff); 460 hdr->e_shoff = TO_NATIVE(hdr->e_shoff); 461 hdr->e_flags = TO_NATIVE(hdr->e_flags); 462 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize); 463 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize); 464 hdr->e_phnum = TO_NATIVE(hdr->e_phnum); 465 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize); 466 hdr->e_shnum = TO_NATIVE(hdr->e_shnum); 467 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); 468 sechdrs = (void *)hdr + hdr->e_shoff; 469 info->sechdrs = sechdrs; 470 471 /* Check if file offset is correct */ 472 if (hdr->e_shoff > info->size) { 473 fatal("section header offset=%lu in file '%s' is bigger than " 474 "filesize=%lu\n", (unsigned long)hdr->e_shoff, 475 filename, info->size); 476 return 0; 477 } 478 479 if (hdr->e_shnum == SHN_UNDEF) { 480 /* 481 * There are more than 64k sections, 482 * read count from .sh_size. 483 */ 484 info->num_sections = TO_NATIVE(sechdrs[0].sh_size); 485 } 486 else { 487 info->num_sections = hdr->e_shnum; 488 } 489 if (hdr->e_shstrndx == SHN_XINDEX) { 490 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link); 491 } 492 else { 493 info->secindex_strings = hdr->e_shstrndx; 494 } 495 496 /* Fix endianness in section headers */ 497 for (i = 0; i < info->num_sections; i++) { 498 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); 499 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); 500 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags); 501 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr); 502 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); 503 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); 504 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); 505 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info); 506 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign); 507 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize); 508 } 509 /* Find symbol table. */ 510 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset; 511 for (i = 1; i < info->num_sections; i++) { 512 const char *secname; 513 int nobits = sechdrs[i].sh_type == SHT_NOBITS; 514 515 if (!nobits && sechdrs[i].sh_offset > info->size) { 516 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > " 517 "sizeof(*hrd)=%zu\n", filename, 518 (unsigned long)sechdrs[i].sh_offset, 519 sizeof(*hdr)); 520 return 0; 521 } 522 secname = secstrings + sechdrs[i].sh_name; 523 if (strcmp(secname, ".modinfo") == 0) { 524 if (nobits) 525 fatal("%s has NOBITS .modinfo\n", filename); 526 info->modinfo = (void *)hdr + sechdrs[i].sh_offset; 527 info->modinfo_len = sechdrs[i].sh_size; 528 } else if (strcmp(secname, "__ksymtab") == 0) 529 info->export_sec = i; 530 else if (strcmp(secname, "__ksymtab_unused") == 0) 531 info->export_unused_sec = i; 532 else if (strcmp(secname, "__ksymtab_gpl") == 0) 533 info->export_gpl_sec = i; 534 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0) 535 info->export_unused_gpl_sec = i; 536 else if (strcmp(secname, "__ksymtab_gpl_future") == 0) 537 info->export_gpl_future_sec = i; 538 539 if (sechdrs[i].sh_type == SHT_SYMTAB) { 540 unsigned int sh_link_idx; 541 symtab_idx = i; 542 info->symtab_start = (void *)hdr + 543 sechdrs[i].sh_offset; 544 info->symtab_stop = (void *)hdr + 545 sechdrs[i].sh_offset + sechdrs[i].sh_size; 546 sh_link_idx = sechdrs[i].sh_link; 547 info->strtab = (void *)hdr + 548 sechdrs[sh_link_idx].sh_offset; 549 } 550 551 /* 32bit section no. table? ("more than 64k sections") */ 552 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) { 553 symtab_shndx_idx = i; 554 info->symtab_shndx_start = (void *)hdr + 555 sechdrs[i].sh_offset; 556 info->symtab_shndx_stop = (void *)hdr + 557 sechdrs[i].sh_offset + sechdrs[i].sh_size; 558 } 559 } 560 if (!info->symtab_start) 561 fatal("%s has no symtab?\n", filename); 562 563 /* Fix endianness in symbols */ 564 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) { 565 sym->st_shndx = TO_NATIVE(sym->st_shndx); 566 sym->st_name = TO_NATIVE(sym->st_name); 567 sym->st_value = TO_NATIVE(sym->st_value); 568 sym->st_size = TO_NATIVE(sym->st_size); 569 } 570 571 if (symtab_shndx_idx != ~0U) { 572 Elf32_Word *p; 573 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link) 574 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n", 575 filename, sechdrs[symtab_shndx_idx].sh_link, 576 symtab_idx); 577 /* Fix endianness */ 578 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop; 579 p++) 580 *p = TO_NATIVE(*p); 581 } 582 583 return 1; 584 } 585 586 static void parse_elf_finish(struct elf_info *info) 587 { 588 release_file(info->hdr, info->size); 589 } 590 591 static int ignore_undef_symbol(struct elf_info *info, const char *symname) 592 { 593 /* ignore __this_module, it will be resolved shortly */ 594 if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0) 595 return 1; 596 /* ignore global offset table */ 597 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) 598 return 1; 599 if (info->hdr->e_machine == EM_PPC) 600 /* Special register function linked on all modules during final link of .ko */ 601 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 || 602 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 || 603 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 || 604 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 || 605 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 || 606 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0) 607 return 1; 608 if (info->hdr->e_machine == EM_PPC64) 609 /* Special register function linked on all modules during final link of .ko */ 610 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 || 611 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 || 612 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 || 613 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0 || 614 strcmp(symname, ".TOC.") == 0) 615 return 1; 616 /* Do not ignore this symbol */ 617 return 0; 618 } 619 620 #define CRC_PFX VMLINUX_SYMBOL_STR(__crc_) 621 #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_) 622 623 static void handle_modversions(struct module *mod, struct elf_info *info, 624 Elf_Sym *sym, const char *symname) 625 { 626 unsigned int crc; 627 enum export export; 628 bool is_crc = false; 629 630 if ((!is_vmlinux(mod->name) || mod->is_dot_o) && 631 strncmp(symname, "__ksymtab", 9) == 0) 632 export = export_from_secname(info, get_secindex(info, sym)); 633 else 634 export = export_from_sec(info, get_secindex(info, sym)); 635 636 /* CRC'd symbol */ 637 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) { 638 is_crc = true; 639 crc = (unsigned int) sym->st_value; 640 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) { 641 unsigned int *crcp; 642 643 /* symbol points to the CRC in the ELF object */ 644 crcp = (void *)info->hdr + sym->st_value + 645 info->sechdrs[sym->st_shndx].sh_offset - 646 (info->hdr->e_type != ET_REL ? 647 info->sechdrs[sym->st_shndx].sh_addr : 0); 648 crc = *crcp; 649 } 650 sym_update_crc(symname + strlen(CRC_PFX), mod, crc, 651 export); 652 } 653 654 switch (sym->st_shndx) { 655 case SHN_COMMON: 656 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) { 657 /* Should warn here, but modpost runs before the linker */ 658 } else 659 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); 660 break; 661 case SHN_UNDEF: 662 /* undefined symbol */ 663 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && 664 ELF_ST_BIND(sym->st_info) != STB_WEAK) 665 break; 666 if (ignore_undef_symbol(info, symname)) 667 break; 668 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */ 669 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER) 670 /* add compatibility with older glibc */ 671 #ifndef STT_SPARC_REGISTER 672 #define STT_SPARC_REGISTER STT_REGISTER 673 #endif 674 if (info->hdr->e_machine == EM_SPARC || 675 info->hdr->e_machine == EM_SPARCV9) { 676 /* Ignore register directives. */ 677 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER) 678 break; 679 if (symname[0] == '.') { 680 char *munged = strdup(symname); 681 munged[0] = '_'; 682 munged[1] = toupper(munged[1]); 683 symname = munged; 684 } 685 } 686 #endif 687 688 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX 689 if (symname[0] != '_') 690 break; 691 else 692 symname++; 693 #endif 694 if (is_crc) { 695 const char *e = is_vmlinux(mod->name) ?"":".ko"; 696 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", symname + strlen(CRC_PFX), mod->name, e); 697 } 698 mod->unres = alloc_symbol(symname, 699 ELF_ST_BIND(sym->st_info) == STB_WEAK, 700 mod->unres); 701 break; 702 default: 703 /* All exported symbols */ 704 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) { 705 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod, 706 export); 707 } 708 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0) 709 mod->has_init = 1; 710 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0) 711 mod->has_cleanup = 1; 712 break; 713 } 714 } 715 716 /** 717 * Parse tag=value strings from .modinfo section 718 **/ 719 static char *next_string(char *string, unsigned long *secsize) 720 { 721 /* Skip non-zero chars */ 722 while (string[0]) { 723 string++; 724 if ((*secsize)-- <= 1) 725 return NULL; 726 } 727 728 /* Skip any zero padding. */ 729 while (!string[0]) { 730 string++; 731 if ((*secsize)-- <= 1) 732 return NULL; 733 } 734 return string; 735 } 736 737 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len, 738 const char *tag, char *info) 739 { 740 char *p; 741 unsigned int taglen = strlen(tag); 742 unsigned long size = modinfo_len; 743 744 if (info) { 745 size -= info - (char *)modinfo; 746 modinfo = next_string(info, &size); 747 } 748 749 for (p = modinfo; p; p = next_string(p, &size)) { 750 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') 751 return p + taglen + 1; 752 } 753 return NULL; 754 } 755 756 static char *get_modinfo(void *modinfo, unsigned long modinfo_len, 757 const char *tag) 758 759 { 760 return get_next_modinfo(modinfo, modinfo_len, tag, NULL); 761 } 762 763 /** 764 * Test if string s ends in string sub 765 * return 0 if match 766 **/ 767 static int strrcmp(const char *s, const char *sub) 768 { 769 int slen, sublen; 770 771 if (!s || !sub) 772 return 1; 773 774 slen = strlen(s); 775 sublen = strlen(sub); 776 777 if ((slen == 0) || (sublen == 0)) 778 return 1; 779 780 if (sublen > slen) 781 return 1; 782 783 return memcmp(s + slen - sublen, sub, sublen); 784 } 785 786 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym) 787 { 788 if (sym) 789 return elf->strtab + sym->st_name; 790 else 791 return "(unknown)"; 792 } 793 794 /* The pattern is an array of simple patterns. 795 * "foo" will match an exact string equal to "foo" 796 * "*foo" will match a string that ends with "foo" 797 * "foo*" will match a string that begins with "foo" 798 * "*foo*" will match a string that contains "foo" 799 */ 800 static int match(const char *sym, const char * const pat[]) 801 { 802 const char *p; 803 while (*pat) { 804 p = *pat++; 805 const char *endp = p + strlen(p) - 1; 806 807 /* "*foo*" */ 808 if (*p == '*' && *endp == '*') { 809 char *here, *bare = strndup(p + 1, strlen(p) - 2); 810 811 here = strstr(sym, bare); 812 free(bare); 813 if (here != NULL) 814 return 1; 815 } 816 /* "*foo" */ 817 else if (*p == '*') { 818 if (strrcmp(sym, p + 1) == 0) 819 return 1; 820 } 821 /* "foo*" */ 822 else if (*endp == '*') { 823 if (strncmp(sym, p, strlen(p) - 1) == 0) 824 return 1; 825 } 826 /* no wildcards */ 827 else { 828 if (strcmp(p, sym) == 0) 829 return 1; 830 } 831 } 832 /* no match */ 833 return 0; 834 } 835 836 /* sections that we do not want to do full section mismatch check on */ 837 static const char *const section_white_list[] = 838 { 839 ".comment*", 840 ".debug*", 841 ".cranges", /* sh64 */ 842 ".zdebug*", /* Compressed debug sections. */ 843 ".GCC.command.line", /* record-gcc-switches */ 844 ".mdebug*", /* alpha, score, mips etc. */ 845 ".pdr", /* alpha, score, mips etc. */ 846 ".stab*", 847 ".note*", 848 ".got*", 849 ".toc*", 850 ".xt.prop", /* xtensa */ 851 ".xt.lit", /* xtensa */ 852 ".arcextmap*", /* arc */ 853 ".gnu.linkonce.arcext*", /* arc : modules */ 854 ".cmem*", /* EZchip */ 855 ".fmt_slot*", /* EZchip */ 856 ".gnu.lto*", 857 ".discard.*", 858 NULL 859 }; 860 861 /* 862 * This is used to find sections missing the SHF_ALLOC flag. 863 * The cause of this is often a section specified in assembler 864 * without "ax" / "aw". 865 */ 866 static void check_section(const char *modname, struct elf_info *elf, 867 Elf_Shdr *sechdr) 868 { 869 const char *sec = sech_name(elf, sechdr); 870 871 if (sechdr->sh_type == SHT_PROGBITS && 872 !(sechdr->sh_flags & SHF_ALLOC) && 873 !match(sec, section_white_list)) { 874 warn("%s (%s): unexpected non-allocatable section.\n" 875 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n" 876 "Note that for example <linux/init.h> contains\n" 877 "section definitions for use in .S files.\n\n", 878 modname, sec); 879 } 880 } 881 882 883 884 #define ALL_INIT_DATA_SECTIONS \ 885 ".init.setup", ".init.rodata", ".meminit.rodata", \ 886 ".init.data", ".meminit.data" 887 #define ALL_EXIT_DATA_SECTIONS \ 888 ".exit.data", ".memexit.data" 889 890 #define ALL_INIT_TEXT_SECTIONS \ 891 ".init.text", ".meminit.text" 892 #define ALL_EXIT_TEXT_SECTIONS \ 893 ".exit.text", ".memexit.text" 894 895 #define ALL_PCI_INIT_SECTIONS \ 896 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \ 897 ".pci_fixup_enable", ".pci_fixup_resume", \ 898 ".pci_fixup_resume_early", ".pci_fixup_suspend" 899 900 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS 901 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS 902 903 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS 904 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS 905 906 #define DATA_SECTIONS ".data", ".data.rel" 907 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ 908 ".kprobes.text", ".cpuidle.text" 909 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ 910 ".fixup", ".entry.text", ".exception.text", ".text.*", \ 911 ".coldtext" 912 913 #define INIT_SECTIONS ".init.*" 914 #define MEM_INIT_SECTIONS ".meminit.*" 915 916 #define EXIT_SECTIONS ".exit.*" 917 #define MEM_EXIT_SECTIONS ".memexit.*" 918 919 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \ 920 TEXT_SECTIONS, OTHER_TEXT_SECTIONS 921 922 /* init data sections */ 923 static const char *const init_data_sections[] = 924 { ALL_INIT_DATA_SECTIONS, NULL }; 925 926 /* all init sections */ 927 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL }; 928 929 /* All init and exit sections (code + data) */ 930 static const char *const init_exit_sections[] = 931 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }; 932 933 /* all text sections */ 934 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL }; 935 936 /* data section */ 937 static const char *const data_sections[] = { DATA_SECTIONS, NULL }; 938 939 940 /* symbols in .data that may refer to init/exit sections */ 941 #define DEFAULT_SYMBOL_WHITE_LIST \ 942 "*driver", \ 943 "*_template", /* scsi uses *_template a lot */ \ 944 "*_timer", /* arm uses ops structures named _timer a lot */ \ 945 "*_sht", /* scsi also used *_sht to some extent */ \ 946 "*_ops", \ 947 "*_probe", \ 948 "*_probe_one", \ 949 "*_console" 950 951 static const char *const head_sections[] = { ".head.text*", NULL }; 952 static const char *const linker_symbols[] = 953 { "__init_begin", "_sinittext", "_einittext", NULL }; 954 static const char *const optim_symbols[] = { "*.constprop.*", NULL }; 955 956 enum mismatch { 957 TEXT_TO_ANY_INIT, 958 DATA_TO_ANY_INIT, 959 TEXT_TO_ANY_EXIT, 960 DATA_TO_ANY_EXIT, 961 XXXINIT_TO_SOME_INIT, 962 XXXEXIT_TO_SOME_EXIT, 963 ANY_INIT_TO_ANY_EXIT, 964 ANY_EXIT_TO_ANY_INIT, 965 EXPORT_TO_INIT_EXIT, 966 EXTABLE_TO_NON_TEXT, 967 }; 968 969 /** 970 * Describe how to match sections on different criterias: 971 * 972 * @fromsec: Array of sections to be matched. 973 * 974 * @bad_tosec: Relocations applied to a section in @fromsec to a section in 975 * this array is forbidden (black-list). Can be empty. 976 * 977 * @good_tosec: Relocations applied to a section in @fromsec must be 978 * targetting sections in this array (white-list). Can be empty. 979 * 980 * @mismatch: Type of mismatch. 981 * 982 * @symbol_white_list: Do not match a relocation to a symbol in this list 983 * even if it is targetting a section in @bad_to_sec. 984 * 985 * @handler: Specific handler to call when a match is found. If NULL, 986 * default_mismatch_handler() will be called. 987 * 988 */ 989 struct sectioncheck { 990 const char *fromsec[20]; 991 const char *bad_tosec[20]; 992 const char *good_tosec[20]; 993 enum mismatch mismatch; 994 const char *symbol_white_list[20]; 995 void (*handler)(const char *modname, struct elf_info *elf, 996 const struct sectioncheck* const mismatch, 997 Elf_Rela *r, Elf_Sym *sym, const char *fromsec); 998 999 }; 1000 1001 static void extable_mismatch_handler(const char *modname, struct elf_info *elf, 1002 const struct sectioncheck* const mismatch, 1003 Elf_Rela *r, Elf_Sym *sym, 1004 const char *fromsec); 1005 1006 static const struct sectioncheck sectioncheck[] = { 1007 /* Do not reference init/exit code/data from 1008 * normal code and data 1009 */ 1010 { 1011 .fromsec = { TEXT_SECTIONS, NULL }, 1012 .bad_tosec = { ALL_INIT_SECTIONS, NULL }, 1013 .mismatch = TEXT_TO_ANY_INIT, 1014 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1015 }, 1016 { 1017 .fromsec = { DATA_SECTIONS, NULL }, 1018 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, 1019 .mismatch = DATA_TO_ANY_INIT, 1020 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1021 }, 1022 { 1023 .fromsec = { DATA_SECTIONS, NULL }, 1024 .bad_tosec = { INIT_SECTIONS, NULL }, 1025 .mismatch = DATA_TO_ANY_INIT, 1026 .symbol_white_list = { 1027 "*_template", "*_timer", "*_sht", "*_ops", 1028 "*_probe", "*_probe_one", "*_console", NULL 1029 }, 1030 }, 1031 { 1032 .fromsec = { TEXT_SECTIONS, NULL }, 1033 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 1034 .mismatch = TEXT_TO_ANY_EXIT, 1035 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1036 }, 1037 { 1038 .fromsec = { DATA_SECTIONS, NULL }, 1039 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 1040 .mismatch = DATA_TO_ANY_EXIT, 1041 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1042 }, 1043 /* Do not reference init code/data from meminit code/data */ 1044 { 1045 .fromsec = { ALL_XXXINIT_SECTIONS, NULL }, 1046 .bad_tosec = { INIT_SECTIONS, NULL }, 1047 .mismatch = XXXINIT_TO_SOME_INIT, 1048 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1049 }, 1050 /* Do not reference exit code/data from memexit code/data */ 1051 { 1052 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL }, 1053 .bad_tosec = { EXIT_SECTIONS, NULL }, 1054 .mismatch = XXXEXIT_TO_SOME_EXIT, 1055 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1056 }, 1057 /* Do not use exit code/data from init code */ 1058 { 1059 .fromsec = { ALL_INIT_SECTIONS, NULL }, 1060 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 1061 .mismatch = ANY_INIT_TO_ANY_EXIT, 1062 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1063 }, 1064 /* Do not use init code/data from exit code */ 1065 { 1066 .fromsec = { ALL_EXIT_SECTIONS, NULL }, 1067 .bad_tosec = { ALL_INIT_SECTIONS, NULL }, 1068 .mismatch = ANY_EXIT_TO_ANY_INIT, 1069 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1070 }, 1071 { 1072 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL }, 1073 .bad_tosec = { INIT_SECTIONS, NULL }, 1074 .mismatch = ANY_INIT_TO_ANY_EXIT, 1075 .symbol_white_list = { NULL }, 1076 }, 1077 /* Do not export init/exit functions or data */ 1078 { 1079 .fromsec = { "__ksymtab*", NULL }, 1080 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, 1081 .mismatch = EXPORT_TO_INIT_EXIT, 1082 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1083 }, 1084 { 1085 .fromsec = { "__ex_table", NULL }, 1086 /* If you're adding any new black-listed sections in here, consider 1087 * adding a special 'printer' for them in scripts/check_extable. 1088 */ 1089 .bad_tosec = { ".altinstr_replacement", NULL }, 1090 .good_tosec = {ALL_TEXT_SECTIONS , NULL}, 1091 .mismatch = EXTABLE_TO_NON_TEXT, 1092 .handler = extable_mismatch_handler, 1093 } 1094 }; 1095 1096 static const struct sectioncheck *section_mismatch( 1097 const char *fromsec, const char *tosec) 1098 { 1099 int i; 1100 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck); 1101 const struct sectioncheck *check = §ioncheck[0]; 1102 1103 /* 1104 * The target section could be the SHT_NUL section when we're 1105 * handling relocations to un-resolved symbols, trying to match it 1106 * doesn't make much sense and causes build failures on parisc 1107 * architectures. 1108 */ 1109 if (*tosec == '\0') 1110 return NULL; 1111 1112 for (i = 0; i < elems; i++) { 1113 if (match(fromsec, check->fromsec)) { 1114 if (check->bad_tosec[0] && match(tosec, check->bad_tosec)) 1115 return check; 1116 if (check->good_tosec[0] && !match(tosec, check->good_tosec)) 1117 return check; 1118 } 1119 check++; 1120 } 1121 return NULL; 1122 } 1123 1124 /** 1125 * Whitelist to allow certain references to pass with no warning. 1126 * 1127 * Pattern 1: 1128 * If a module parameter is declared __initdata and permissions=0 1129 * then this is legal despite the warning generated. 1130 * We cannot see value of permissions here, so just ignore 1131 * this pattern. 1132 * The pattern is identified by: 1133 * tosec = .init.data 1134 * fromsec = .data* 1135 * atsym =__param* 1136 * 1137 * Pattern 1a: 1138 * module_param_call() ops can refer to __init set function if permissions=0 1139 * The pattern is identified by: 1140 * tosec = .init.text 1141 * fromsec = .data* 1142 * atsym = __param_ops_* 1143 * 1144 * Pattern 2: 1145 * Many drivers utilise a *driver container with references to 1146 * add, remove, probe functions etc. 1147 * the pattern is identified by: 1148 * tosec = init or exit section 1149 * fromsec = data section 1150 * atsym = *driver, *_template, *_sht, *_ops, *_probe, 1151 * *probe_one, *_console, *_timer 1152 * 1153 * Pattern 3: 1154 * Whitelist all references from .head.text to any init section 1155 * 1156 * Pattern 4: 1157 * Some symbols belong to init section but still it is ok to reference 1158 * these from non-init sections as these symbols don't have any memory 1159 * allocated for them and symbol address and value are same. So even 1160 * if init section is freed, its ok to reference those symbols. 1161 * For ex. symbols marking the init section boundaries. 1162 * This pattern is identified by 1163 * refsymname = __init_begin, _sinittext, _einittext 1164 * 1165 * Pattern 5: 1166 * GCC may optimize static inlines when fed constant arg(s) resulting 1167 * in functions like cpumask_empty() -- generating an associated symbol 1168 * cpumask_empty.constprop.3 that appears in the audit. If the const that 1169 * is passed in comes from __init, like say nmi_ipi_mask, we get a 1170 * meaningless section warning. May need to add isra symbols too... 1171 * This pattern is identified by 1172 * tosec = init section 1173 * fromsec = text section 1174 * refsymname = *.constprop.* 1175 * 1176 **/ 1177 static int secref_whitelist(const struct sectioncheck *mismatch, 1178 const char *fromsec, const char *fromsym, 1179 const char *tosec, const char *tosym) 1180 { 1181 /* Check for pattern 1 */ 1182 if (match(tosec, init_data_sections) && 1183 match(fromsec, data_sections) && 1184 (strncmp(fromsym, "__param", strlen("__param")) == 0)) 1185 return 0; 1186 1187 /* Check for pattern 1a */ 1188 if (strcmp(tosec, ".init.text") == 0 && 1189 match(fromsec, data_sections) && 1190 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0)) 1191 return 0; 1192 1193 /* Check for pattern 2 */ 1194 if (match(tosec, init_exit_sections) && 1195 match(fromsec, data_sections) && 1196 match(fromsym, mismatch->symbol_white_list)) 1197 return 0; 1198 1199 /* Check for pattern 3 */ 1200 if (match(fromsec, head_sections) && 1201 match(tosec, init_sections)) 1202 return 0; 1203 1204 /* Check for pattern 4 */ 1205 if (match(tosym, linker_symbols)) 1206 return 0; 1207 1208 /* Check for pattern 5 */ 1209 if (match(fromsec, text_sections) && 1210 match(tosec, init_sections) && 1211 match(fromsym, optim_symbols)) 1212 return 0; 1213 1214 return 1; 1215 } 1216 1217 /** 1218 * Find symbol based on relocation record info. 1219 * In some cases the symbol supplied is a valid symbol so 1220 * return refsym. If st_name != 0 we assume this is a valid symbol. 1221 * In other cases the symbol needs to be looked up in the symbol table 1222 * based on section and address. 1223 * **/ 1224 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, 1225 Elf_Sym *relsym) 1226 { 1227 Elf_Sym *sym; 1228 Elf_Sym *near = NULL; 1229 Elf64_Sword distance = 20; 1230 Elf64_Sword d; 1231 unsigned int relsym_secindex; 1232 1233 if (relsym->st_name != 0) 1234 return relsym; 1235 1236 relsym_secindex = get_secindex(elf, relsym); 1237 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1238 if (get_secindex(elf, sym) != relsym_secindex) 1239 continue; 1240 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) 1241 continue; 1242 if (sym->st_value == addr) 1243 return sym; 1244 /* Find a symbol nearby - addr are maybe negative */ 1245 d = sym->st_value - addr; 1246 if (d < 0) 1247 d = addr - sym->st_value; 1248 if (d < distance) { 1249 distance = d; 1250 near = sym; 1251 } 1252 } 1253 /* We need a close match */ 1254 if (distance < 20) 1255 return near; 1256 else 1257 return NULL; 1258 } 1259 1260 static inline int is_arm_mapping_symbol(const char *str) 1261 { 1262 return str[0] == '$' && strchr("axtd", str[1]) 1263 && (str[2] == '\0' || str[2] == '.'); 1264 } 1265 1266 /* 1267 * If there's no name there, ignore it; likewise, ignore it if it's 1268 * one of the magic symbols emitted used by current ARM tools. 1269 * 1270 * Otherwise if find_symbols_between() returns those symbols, they'll 1271 * fail the whitelist tests and cause lots of false alarms ... fixable 1272 * only by merging __exit and __init sections into __text, bloating 1273 * the kernel (which is especially evil on embedded platforms). 1274 */ 1275 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) 1276 { 1277 const char *name = elf->strtab + sym->st_name; 1278 1279 if (!name || !strlen(name)) 1280 return 0; 1281 return !is_arm_mapping_symbol(name); 1282 } 1283 1284 /* 1285 * Find symbols before or equal addr and after addr - in the section sec. 1286 * If we find two symbols with equal offset prefer one with a valid name. 1287 * The ELF format may have a better way to detect what type of symbol 1288 * it is, but this works for now. 1289 **/ 1290 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, 1291 const char *sec) 1292 { 1293 Elf_Sym *sym; 1294 Elf_Sym *near = NULL; 1295 Elf_Addr distance = ~0; 1296 1297 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1298 const char *symsec; 1299 1300 if (is_shndx_special(sym->st_shndx)) 1301 continue; 1302 symsec = sec_name(elf, get_secindex(elf, sym)); 1303 if (strcmp(symsec, sec) != 0) 1304 continue; 1305 if (!is_valid_name(elf, sym)) 1306 continue; 1307 if (sym->st_value <= addr) { 1308 if ((addr - sym->st_value) < distance) { 1309 distance = addr - sym->st_value; 1310 near = sym; 1311 } else if ((addr - sym->st_value) == distance) { 1312 near = sym; 1313 } 1314 } 1315 } 1316 return near; 1317 } 1318 1319 /* 1320 * Convert a section name to the function/data attribute 1321 * .init.text => __init 1322 * .memexitconst => __memconst 1323 * etc. 1324 * 1325 * The memory of returned value has been allocated on a heap. The user of this 1326 * method should free it after usage. 1327 */ 1328 static char *sec2annotation(const char *s) 1329 { 1330 if (match(s, init_exit_sections)) { 1331 char *p = malloc(20); 1332 char *r = p; 1333 1334 *p++ = '_'; 1335 *p++ = '_'; 1336 if (*s == '.') 1337 s++; 1338 while (*s && *s != '.') 1339 *p++ = *s++; 1340 *p = '\0'; 1341 if (*s == '.') 1342 s++; 1343 if (strstr(s, "rodata") != NULL) 1344 strcat(p, "const "); 1345 else if (strstr(s, "data") != NULL) 1346 strcat(p, "data "); 1347 else 1348 strcat(p, " "); 1349 return r; 1350 } else { 1351 return strdup(""); 1352 } 1353 } 1354 1355 static int is_function(Elf_Sym *sym) 1356 { 1357 if (sym) 1358 return ELF_ST_TYPE(sym->st_info) == STT_FUNC; 1359 else 1360 return -1; 1361 } 1362 1363 static void print_section_list(const char * const list[20]) 1364 { 1365 const char *const *s = list; 1366 1367 while (*s) { 1368 fprintf(stderr, "%s", *s); 1369 s++; 1370 if (*s) 1371 fprintf(stderr, ", "); 1372 } 1373 fprintf(stderr, "\n"); 1374 } 1375 1376 static inline void get_pretty_name(int is_func, const char** name, const char** name_p) 1377 { 1378 switch (is_func) { 1379 case 0: *name = "variable"; *name_p = ""; break; 1380 case 1: *name = "function"; *name_p = "()"; break; 1381 default: *name = "(unknown reference)"; *name_p = ""; break; 1382 } 1383 } 1384 1385 /* 1386 * Print a warning about a section mismatch. 1387 * Try to find symbols near it so user can find it. 1388 * Check whitelist before warning - it may be a false positive. 1389 */ 1390 static void report_sec_mismatch(const char *modname, 1391 const struct sectioncheck *mismatch, 1392 const char *fromsec, 1393 unsigned long long fromaddr, 1394 const char *fromsym, 1395 int from_is_func, 1396 const char *tosec, const char *tosym, 1397 int to_is_func) 1398 { 1399 const char *from, *from_p; 1400 const char *to, *to_p; 1401 char *prl_from; 1402 char *prl_to; 1403 1404 sec_mismatch_count++; 1405 if (!sec_mismatch_verbose) 1406 return; 1407 1408 get_pretty_name(from_is_func, &from, &from_p); 1409 get_pretty_name(to_is_func, &to, &to_p); 1410 1411 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s " 1412 "to the %s %s:%s%s\n", 1413 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec, 1414 tosym, to_p); 1415 1416 switch (mismatch->mismatch) { 1417 case TEXT_TO_ANY_INIT: 1418 prl_from = sec2annotation(fromsec); 1419 prl_to = sec2annotation(tosec); 1420 fprintf(stderr, 1421 "The function %s%s() references\n" 1422 "the %s %s%s%s.\n" 1423 "This is often because %s lacks a %s\n" 1424 "annotation or the annotation of %s is wrong.\n", 1425 prl_from, fromsym, 1426 to, prl_to, tosym, to_p, 1427 fromsym, prl_to, tosym); 1428 free(prl_from); 1429 free(prl_to); 1430 break; 1431 case DATA_TO_ANY_INIT: { 1432 prl_to = sec2annotation(tosec); 1433 fprintf(stderr, 1434 "The variable %s references\n" 1435 "the %s %s%s%s\n" 1436 "If the reference is valid then annotate the\n" 1437 "variable with __init* or __refdata (see linux/init.h) " 1438 "or name the variable:\n", 1439 fromsym, to, prl_to, tosym, to_p); 1440 print_section_list(mismatch->symbol_white_list); 1441 free(prl_to); 1442 break; 1443 } 1444 case TEXT_TO_ANY_EXIT: 1445 prl_to = sec2annotation(tosec); 1446 fprintf(stderr, 1447 "The function %s() references a %s in an exit section.\n" 1448 "Often the %s %s%s has valid usage outside the exit section\n" 1449 "and the fix is to remove the %sannotation of %s.\n", 1450 fromsym, to, to, tosym, to_p, prl_to, tosym); 1451 free(prl_to); 1452 break; 1453 case DATA_TO_ANY_EXIT: { 1454 prl_to = sec2annotation(tosec); 1455 fprintf(stderr, 1456 "The variable %s references\n" 1457 "the %s %s%s%s\n" 1458 "If the reference is valid then annotate the\n" 1459 "variable with __exit* (see linux/init.h) or " 1460 "name the variable:\n", 1461 fromsym, to, prl_to, tosym, to_p); 1462 print_section_list(mismatch->symbol_white_list); 1463 free(prl_to); 1464 break; 1465 } 1466 case XXXINIT_TO_SOME_INIT: 1467 case XXXEXIT_TO_SOME_EXIT: 1468 prl_from = sec2annotation(fromsec); 1469 prl_to = sec2annotation(tosec); 1470 fprintf(stderr, 1471 "The %s %s%s%s references\n" 1472 "a %s %s%s%s.\n" 1473 "If %s is only used by %s then\n" 1474 "annotate %s with a matching annotation.\n", 1475 from, prl_from, fromsym, from_p, 1476 to, prl_to, tosym, to_p, 1477 tosym, fromsym, tosym); 1478 free(prl_from); 1479 free(prl_to); 1480 break; 1481 case ANY_INIT_TO_ANY_EXIT: 1482 prl_from = sec2annotation(fromsec); 1483 prl_to = sec2annotation(tosec); 1484 fprintf(stderr, 1485 "The %s %s%s%s references\n" 1486 "a %s %s%s%s.\n" 1487 "This is often seen when error handling " 1488 "in the init function\n" 1489 "uses functionality in the exit path.\n" 1490 "The fix is often to remove the %sannotation of\n" 1491 "%s%s so it may be used outside an exit section.\n", 1492 from, prl_from, fromsym, from_p, 1493 to, prl_to, tosym, to_p, 1494 prl_to, tosym, to_p); 1495 free(prl_from); 1496 free(prl_to); 1497 break; 1498 case ANY_EXIT_TO_ANY_INIT: 1499 prl_from = sec2annotation(fromsec); 1500 prl_to = sec2annotation(tosec); 1501 fprintf(stderr, 1502 "The %s %s%s%s references\n" 1503 "a %s %s%s%s.\n" 1504 "This is often seen when error handling " 1505 "in the exit function\n" 1506 "uses functionality in the init path.\n" 1507 "The fix is often to remove the %sannotation of\n" 1508 "%s%s so it may be used outside an init section.\n", 1509 from, prl_from, fromsym, from_p, 1510 to, prl_to, tosym, to_p, 1511 prl_to, tosym, to_p); 1512 free(prl_from); 1513 free(prl_to); 1514 break; 1515 case EXPORT_TO_INIT_EXIT: 1516 prl_to = sec2annotation(tosec); 1517 fprintf(stderr, 1518 "The symbol %s is exported and annotated %s\n" 1519 "Fix this by removing the %sannotation of %s " 1520 "or drop the export.\n", 1521 tosym, prl_to, prl_to, tosym); 1522 free(prl_to); 1523 break; 1524 case EXTABLE_TO_NON_TEXT: 1525 fatal("There's a special handler for this mismatch type, " 1526 "we should never get here."); 1527 break; 1528 } 1529 fprintf(stderr, "\n"); 1530 } 1531 1532 static void default_mismatch_handler(const char *modname, struct elf_info *elf, 1533 const struct sectioncheck* const mismatch, 1534 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1535 { 1536 const char *tosec; 1537 Elf_Sym *to; 1538 Elf_Sym *from; 1539 const char *tosym; 1540 const char *fromsym; 1541 1542 from = find_elf_symbol2(elf, r->r_offset, fromsec); 1543 fromsym = sym_name(elf, from); 1544 1545 if (!strncmp(fromsym, "reference___initcall", 1546 sizeof("reference___initcall")-1)) 1547 return; 1548 1549 tosec = sec_name(elf, get_secindex(elf, sym)); 1550 to = find_elf_symbol(elf, r->r_addend, sym); 1551 tosym = sym_name(elf, to); 1552 1553 /* check whitelist - we may ignore it */ 1554 if (secref_whitelist(mismatch, 1555 fromsec, fromsym, tosec, tosym)) { 1556 report_sec_mismatch(modname, mismatch, 1557 fromsec, r->r_offset, fromsym, 1558 is_function(from), tosec, tosym, 1559 is_function(to)); 1560 } 1561 } 1562 1563 static int is_executable_section(struct elf_info* elf, unsigned int section_index) 1564 { 1565 if (section_index > elf->num_sections) 1566 fatal("section_index is outside elf->num_sections!\n"); 1567 1568 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); 1569 } 1570 1571 /* 1572 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size() 1573 * to know the sizeof(struct exception_table_entry) for the target architecture. 1574 */ 1575 static unsigned int extable_entry_size = 0; 1576 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) 1577 { 1578 /* 1579 * If we're currently checking the second relocation within __ex_table, 1580 * that relocation offset tells us the offsetof(struct 1581 * exception_table_entry, fixup) which is equal to sizeof(struct 1582 * exception_table_entry) divided by two. We use that to our advantage 1583 * since there's no portable way to get that size as every architecture 1584 * seems to go with different sized types. Not pretty but better than 1585 * hard-coding the size for every architecture.. 1586 */ 1587 if (!extable_entry_size) 1588 extable_entry_size = r->r_offset * 2; 1589 } 1590 1591 static inline bool is_extable_fault_address(Elf_Rela *r) 1592 { 1593 /* 1594 * extable_entry_size is only discovered after we've handled the 1595 * _second_ relocation in __ex_table, so only abort when we're not 1596 * handling the first reloc and extable_entry_size is zero. 1597 */ 1598 if (r->r_offset && extable_entry_size == 0) 1599 fatal("extable_entry size hasn't been discovered!\n"); 1600 1601 return ((r->r_offset == 0) || 1602 (r->r_offset % extable_entry_size == 0)); 1603 } 1604 1605 #define is_second_extable_reloc(Start, Cur, Sec) \ 1606 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) 1607 1608 static void report_extable_warnings(const char* modname, struct elf_info* elf, 1609 const struct sectioncheck* const mismatch, 1610 Elf_Rela* r, Elf_Sym* sym, 1611 const char* fromsec, const char* tosec) 1612 { 1613 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec); 1614 const char* fromsym_name = sym_name(elf, fromsym); 1615 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); 1616 const char* tosym_name = sym_name(elf, tosym); 1617 const char* from_pretty_name; 1618 const char* from_pretty_name_p; 1619 const char* to_pretty_name; 1620 const char* to_pretty_name_p; 1621 1622 get_pretty_name(is_function(fromsym), 1623 &from_pretty_name, &from_pretty_name_p); 1624 get_pretty_name(is_function(tosym), 1625 &to_pretty_name, &to_pretty_name_p); 1626 1627 warn("%s(%s+0x%lx): Section mismatch in reference" 1628 " from the %s %s%s to the %s %s:%s%s\n", 1629 modname, fromsec, (long)r->r_offset, from_pretty_name, 1630 fromsym_name, from_pretty_name_p, 1631 to_pretty_name, tosec, tosym_name, to_pretty_name_p); 1632 1633 if (!match(tosec, mismatch->bad_tosec) && 1634 is_executable_section(elf, get_secindex(elf, sym))) 1635 fprintf(stderr, 1636 "The relocation at %s+0x%lx references\n" 1637 "section \"%s\" which is not in the list of\n" 1638 "authorized sections. If you're adding a new section\n" 1639 "and/or if this reference is valid, add \"%s\" to the\n" 1640 "list of authorized sections to jump to on fault.\n" 1641 "This can be achieved by adding \"%s\" to \n" 1642 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", 1643 fromsec, (long)r->r_offset, tosec, tosec, tosec); 1644 } 1645 1646 static void extable_mismatch_handler(const char* modname, struct elf_info *elf, 1647 const struct sectioncheck* const mismatch, 1648 Elf_Rela* r, Elf_Sym* sym, 1649 const char *fromsec) 1650 { 1651 const char* tosec = sec_name(elf, get_secindex(elf, sym)); 1652 1653 sec_mismatch_count++; 1654 1655 if (sec_mismatch_verbose) 1656 report_extable_warnings(modname, elf, mismatch, r, sym, 1657 fromsec, tosec); 1658 1659 if (match(tosec, mismatch->bad_tosec)) 1660 fatal("The relocation at %s+0x%lx references\n" 1661 "section \"%s\" which is black-listed.\n" 1662 "Something is seriously wrong and should be fixed.\n" 1663 "You might get more information about where this is\n" 1664 "coming from by using scripts/check_extable.sh %s\n", 1665 fromsec, (long)r->r_offset, tosec, modname); 1666 else if (!is_executable_section(elf, get_secindex(elf, sym))) { 1667 if (is_extable_fault_address(r)) 1668 fatal("The relocation at %s+0x%lx references\n" 1669 "section \"%s\" which is not executable, IOW\n" 1670 "it is not possible for the kernel to fault\n" 1671 "at that address. Something is seriously wrong\n" 1672 "and should be fixed.\n", 1673 fromsec, (long)r->r_offset, tosec); 1674 else 1675 fatal("The relocation at %s+0x%lx references\n" 1676 "section \"%s\" which is not executable, IOW\n" 1677 "the kernel will fault if it ever tries to\n" 1678 "jump to it. Something is seriously wrong\n" 1679 "and should be fixed.\n", 1680 fromsec, (long)r->r_offset, tosec); 1681 } 1682 } 1683 1684 static void check_section_mismatch(const char *modname, struct elf_info *elf, 1685 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1686 { 1687 const char *tosec = sec_name(elf, get_secindex(elf, sym)); 1688 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); 1689 1690 if (mismatch) { 1691 if (mismatch->handler) 1692 mismatch->handler(modname, elf, mismatch, 1693 r, sym, fromsec); 1694 else 1695 default_mismatch_handler(modname, elf, mismatch, 1696 r, sym, fromsec); 1697 } 1698 } 1699 1700 static unsigned int *reloc_location(struct elf_info *elf, 1701 Elf_Shdr *sechdr, Elf_Rela *r) 1702 { 1703 Elf_Shdr *sechdrs = elf->sechdrs; 1704 int section = sechdr->sh_info; 1705 1706 return (void *)elf->hdr + sechdrs[section].sh_offset + 1707 r->r_offset; 1708 } 1709 1710 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1711 { 1712 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1713 unsigned int *location = reloc_location(elf, sechdr, r); 1714 1715 switch (r_typ) { 1716 case R_386_32: 1717 r->r_addend = TO_NATIVE(*location); 1718 break; 1719 case R_386_PC32: 1720 r->r_addend = TO_NATIVE(*location) + 4; 1721 /* For CONFIG_RELOCATABLE=y */ 1722 if (elf->hdr->e_type == ET_EXEC) 1723 r->r_addend += r->r_offset; 1724 break; 1725 } 1726 return 0; 1727 } 1728 1729 #ifndef R_ARM_CALL 1730 #define R_ARM_CALL 28 1731 #endif 1732 #ifndef R_ARM_JUMP24 1733 #define R_ARM_JUMP24 29 1734 #endif 1735 1736 #ifndef R_ARM_THM_CALL 1737 #define R_ARM_THM_CALL 10 1738 #endif 1739 #ifndef R_ARM_THM_JUMP24 1740 #define R_ARM_THM_JUMP24 30 1741 #endif 1742 #ifndef R_ARM_THM_JUMP19 1743 #define R_ARM_THM_JUMP19 51 1744 #endif 1745 1746 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1747 { 1748 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1749 1750 switch (r_typ) { 1751 case R_ARM_ABS32: 1752 /* From ARM ABI: (S + A) | T */ 1753 r->r_addend = (int)(long) 1754 (elf->symtab_start + ELF_R_SYM(r->r_info)); 1755 break; 1756 case R_ARM_PC24: 1757 case R_ARM_CALL: 1758 case R_ARM_JUMP24: 1759 case R_ARM_THM_CALL: 1760 case R_ARM_THM_JUMP24: 1761 case R_ARM_THM_JUMP19: 1762 /* From ARM ABI: ((S + A) | T) - P */ 1763 r->r_addend = (int)(long)(elf->hdr + 1764 sechdr->sh_offset + 1765 (r->r_offset - sechdr->sh_addr)); 1766 break; 1767 default: 1768 return 1; 1769 } 1770 return 0; 1771 } 1772 1773 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1774 { 1775 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1776 unsigned int *location = reloc_location(elf, sechdr, r); 1777 unsigned int inst; 1778 1779 if (r_typ == R_MIPS_HI16) 1780 return 1; /* skip this */ 1781 inst = TO_NATIVE(*location); 1782 switch (r_typ) { 1783 case R_MIPS_LO16: 1784 r->r_addend = inst & 0xffff; 1785 break; 1786 case R_MIPS_26: 1787 r->r_addend = (inst & 0x03ffffff) << 2; 1788 break; 1789 case R_MIPS_32: 1790 r->r_addend = inst; 1791 break; 1792 } 1793 return 0; 1794 } 1795 1796 static void section_rela(const char *modname, struct elf_info *elf, 1797 Elf_Shdr *sechdr) 1798 { 1799 Elf_Sym *sym; 1800 Elf_Rela *rela; 1801 Elf_Rela r; 1802 unsigned int r_sym; 1803 const char *fromsec; 1804 1805 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; 1806 Elf_Rela *stop = (void *)start + sechdr->sh_size; 1807 1808 fromsec = sech_name(elf, sechdr); 1809 fromsec += strlen(".rela"); 1810 /* if from section (name) is know good then skip it */ 1811 if (match(fromsec, section_white_list)) 1812 return; 1813 1814 for (rela = start; rela < stop; rela++) { 1815 r.r_offset = TO_NATIVE(rela->r_offset); 1816 #if KERNEL_ELFCLASS == ELFCLASS64 1817 if (elf->hdr->e_machine == EM_MIPS) { 1818 unsigned int r_typ; 1819 r_sym = ELF64_MIPS_R_SYM(rela->r_info); 1820 r_sym = TO_NATIVE(r_sym); 1821 r_typ = ELF64_MIPS_R_TYPE(rela->r_info); 1822 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1823 } else { 1824 r.r_info = TO_NATIVE(rela->r_info); 1825 r_sym = ELF_R_SYM(r.r_info); 1826 } 1827 #else 1828 r.r_info = TO_NATIVE(rela->r_info); 1829 r_sym = ELF_R_SYM(r.r_info); 1830 #endif 1831 r.r_addend = TO_NATIVE(rela->r_addend); 1832 sym = elf->symtab_start + r_sym; 1833 /* Skip special sections */ 1834 if (is_shndx_special(sym->st_shndx)) 1835 continue; 1836 if (is_second_extable_reloc(start, rela, fromsec)) 1837 find_extable_entry_size(fromsec, &r); 1838 check_section_mismatch(modname, elf, &r, sym, fromsec); 1839 } 1840 } 1841 1842 static void section_rel(const char *modname, struct elf_info *elf, 1843 Elf_Shdr *sechdr) 1844 { 1845 Elf_Sym *sym; 1846 Elf_Rel *rel; 1847 Elf_Rela r; 1848 unsigned int r_sym; 1849 const char *fromsec; 1850 1851 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; 1852 Elf_Rel *stop = (void *)start + sechdr->sh_size; 1853 1854 fromsec = sech_name(elf, sechdr); 1855 fromsec += strlen(".rel"); 1856 /* if from section (name) is know good then skip it */ 1857 if (match(fromsec, section_white_list)) 1858 return; 1859 1860 for (rel = start; rel < stop; rel++) { 1861 r.r_offset = TO_NATIVE(rel->r_offset); 1862 #if KERNEL_ELFCLASS == ELFCLASS64 1863 if (elf->hdr->e_machine == EM_MIPS) { 1864 unsigned int r_typ; 1865 r_sym = ELF64_MIPS_R_SYM(rel->r_info); 1866 r_sym = TO_NATIVE(r_sym); 1867 r_typ = ELF64_MIPS_R_TYPE(rel->r_info); 1868 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1869 } else { 1870 r.r_info = TO_NATIVE(rel->r_info); 1871 r_sym = ELF_R_SYM(r.r_info); 1872 } 1873 #else 1874 r.r_info = TO_NATIVE(rel->r_info); 1875 r_sym = ELF_R_SYM(r.r_info); 1876 #endif 1877 r.r_addend = 0; 1878 switch (elf->hdr->e_machine) { 1879 case EM_386: 1880 if (addend_386_rel(elf, sechdr, &r)) 1881 continue; 1882 break; 1883 case EM_ARM: 1884 if (addend_arm_rel(elf, sechdr, &r)) 1885 continue; 1886 break; 1887 case EM_MIPS: 1888 if (addend_mips_rel(elf, sechdr, &r)) 1889 continue; 1890 break; 1891 } 1892 sym = elf->symtab_start + r_sym; 1893 /* Skip special sections */ 1894 if (is_shndx_special(sym->st_shndx)) 1895 continue; 1896 if (is_second_extable_reloc(start, rel, fromsec)) 1897 find_extable_entry_size(fromsec, &r); 1898 check_section_mismatch(modname, elf, &r, sym, fromsec); 1899 } 1900 } 1901 1902 /** 1903 * A module includes a number of sections that are discarded 1904 * either when loaded or when used as built-in. 1905 * For loaded modules all functions marked __init and all data 1906 * marked __initdata will be discarded when the module has been initialized. 1907 * Likewise for modules used built-in the sections marked __exit 1908 * are discarded because __exit marked function are supposed to be called 1909 * only when a module is unloaded which never happens for built-in modules. 1910 * The check_sec_ref() function traverses all relocation records 1911 * to find all references to a section that reference a section that will 1912 * be discarded and warns about it. 1913 **/ 1914 static void check_sec_ref(struct module *mod, const char *modname, 1915 struct elf_info *elf) 1916 { 1917 int i; 1918 Elf_Shdr *sechdrs = elf->sechdrs; 1919 1920 /* Walk through all sections */ 1921 for (i = 0; i < elf->num_sections; i++) { 1922 check_section(modname, elf, &elf->sechdrs[i]); 1923 /* We want to process only relocation sections and not .init */ 1924 if (sechdrs[i].sh_type == SHT_RELA) 1925 section_rela(modname, elf, &elf->sechdrs[i]); 1926 else if (sechdrs[i].sh_type == SHT_REL) 1927 section_rel(modname, elf, &elf->sechdrs[i]); 1928 } 1929 } 1930 1931 static char *remove_dot(char *s) 1932 { 1933 size_t n = strcspn(s, "."); 1934 1935 if (n && s[n]) { 1936 size_t m = strspn(s + n + 1, "0123456789"); 1937 if (m && (s[n + m] == '.' || s[n + m] == 0)) 1938 s[n] = 0; 1939 } 1940 return s; 1941 } 1942 1943 static void read_symbols(char *modname) 1944 { 1945 const char *symname; 1946 char *version; 1947 char *license; 1948 struct module *mod; 1949 struct elf_info info = { }; 1950 Elf_Sym *sym; 1951 1952 if (!parse_elf(&info, modname)) 1953 return; 1954 1955 mod = new_module(modname); 1956 1957 /* When there's no vmlinux, don't print warnings about 1958 * unresolved symbols (since there'll be too many ;) */ 1959 if (is_vmlinux(modname)) { 1960 have_vmlinux = 1; 1961 mod->skip = 1; 1962 } 1963 1964 license = get_modinfo(info.modinfo, info.modinfo_len, "license"); 1965 if (!license && !is_vmlinux(modname)) 1966 warn("modpost: missing MODULE_LICENSE() in %s\n" 1967 "see include/linux/module.h for " 1968 "more information\n", modname); 1969 while (license) { 1970 if (license_is_gpl_compatible(license)) 1971 mod->gpl_compatible = 1; 1972 else { 1973 mod->gpl_compatible = 0; 1974 break; 1975 } 1976 license = get_next_modinfo(info.modinfo, info.modinfo_len, 1977 "license", license); 1978 } 1979 1980 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 1981 symname = remove_dot(info.strtab + sym->st_name); 1982 1983 handle_modversions(mod, &info, sym, symname); 1984 handle_moddevtable(mod, &info, sym, symname); 1985 } 1986 if (!is_vmlinux(modname) || 1987 (is_vmlinux(modname) && vmlinux_section_warnings)) 1988 check_sec_ref(mod, modname, &info); 1989 1990 version = get_modinfo(info.modinfo, info.modinfo_len, "version"); 1991 if (version) 1992 maybe_frob_rcs_version(modname, version, info.modinfo, 1993 version - (char *)info.hdr); 1994 if (version || (all_versions && !is_vmlinux(modname))) 1995 get_src_version(modname, mod->srcversion, 1996 sizeof(mod->srcversion)-1); 1997 1998 parse_elf_finish(&info); 1999 2000 /* Our trick to get versioning for module struct etc. - it's 2001 * never passed as an argument to an exported function, so 2002 * the automatic versioning doesn't pick it up, but it's really 2003 * important anyhow */ 2004 if (modversions) 2005 mod->unres = alloc_symbol("module_layout", 0, mod->unres); 2006 } 2007 2008 static void read_symbols_from_files(const char *filename) 2009 { 2010 FILE *in = stdin; 2011 char fname[PATH_MAX]; 2012 2013 if (strcmp(filename, "-") != 0) { 2014 in = fopen(filename, "r"); 2015 if (!in) 2016 fatal("Can't open filenames file %s: %m", filename); 2017 } 2018 2019 while (fgets(fname, PATH_MAX, in) != NULL) { 2020 if (strends(fname, "\n")) 2021 fname[strlen(fname)-1] = '\0'; 2022 read_symbols(fname); 2023 } 2024 2025 if (in != stdin) 2026 fclose(in); 2027 } 2028 2029 #define SZ 500 2030 2031 /* We first write the generated file into memory using the 2032 * following helper, then compare to the file on disk and 2033 * only update the later if anything changed */ 2034 2035 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, 2036 const char *fmt, ...) 2037 { 2038 char tmp[SZ]; 2039 int len; 2040 va_list ap; 2041 2042 va_start(ap, fmt); 2043 len = vsnprintf(tmp, SZ, fmt, ap); 2044 buf_write(buf, tmp, len); 2045 va_end(ap); 2046 } 2047 2048 void buf_write(struct buffer *buf, const char *s, int len) 2049 { 2050 if (buf->size - buf->pos < len) { 2051 buf->size += len + SZ; 2052 buf->p = realloc(buf->p, buf->size); 2053 } 2054 strncpy(buf->p + buf->pos, s, len); 2055 buf->pos += len; 2056 } 2057 2058 static void check_for_gpl_usage(enum export exp, const char *m, const char *s) 2059 { 2060 const char *e = is_vmlinux(m) ?"":".ko"; 2061 2062 switch (exp) { 2063 case export_gpl: 2064 fatal("modpost: GPL-incompatible module %s%s " 2065 "uses GPL-only symbol '%s'\n", m, e, s); 2066 break; 2067 case export_unused_gpl: 2068 fatal("modpost: GPL-incompatible module %s%s " 2069 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s); 2070 break; 2071 case export_gpl_future: 2072 warn("modpost: GPL-incompatible module %s%s " 2073 "uses future GPL-only symbol '%s'\n", m, e, s); 2074 break; 2075 case export_plain: 2076 case export_unused: 2077 case export_unknown: 2078 /* ignore */ 2079 break; 2080 } 2081 } 2082 2083 static void check_for_unused(enum export exp, const char *m, const char *s) 2084 { 2085 const char *e = is_vmlinux(m) ?"":".ko"; 2086 2087 switch (exp) { 2088 case export_unused: 2089 case export_unused_gpl: 2090 warn("modpost: module %s%s " 2091 "uses symbol '%s' marked UNUSED\n", m, e, s); 2092 break; 2093 default: 2094 /* ignore */ 2095 break; 2096 } 2097 } 2098 2099 static void check_exports(struct module *mod) 2100 { 2101 struct symbol *s, *exp; 2102 2103 for (s = mod->unres; s; s = s->next) { 2104 const char *basename; 2105 exp = find_symbol(s->name); 2106 if (!exp || exp->module == mod) 2107 continue; 2108 basename = strrchr(mod->name, '/'); 2109 if (basename) 2110 basename++; 2111 else 2112 basename = mod->name; 2113 if (!mod->gpl_compatible) 2114 check_for_gpl_usage(exp->export, basename, exp->name); 2115 check_for_unused(exp->export, basename, exp->name); 2116 } 2117 } 2118 2119 static int check_modname_len(struct module *mod) 2120 { 2121 const char *mod_name; 2122 2123 mod_name = strrchr(mod->name, '/'); 2124 if (mod_name == NULL) 2125 mod_name = mod->name; 2126 else 2127 mod_name++; 2128 if (strlen(mod_name) >= MODULE_NAME_LEN) { 2129 merror("module name is too long [%s.ko]\n", mod->name); 2130 return 1; 2131 } 2132 2133 return 0; 2134 } 2135 2136 /** 2137 * Header for the generated file 2138 **/ 2139 static void add_header(struct buffer *b, struct module *mod) 2140 { 2141 buf_printf(b, "#include <linux/module.h>\n"); 2142 buf_printf(b, "#include <linux/vermagic.h>\n"); 2143 buf_printf(b, "#include <linux/compiler.h>\n"); 2144 buf_printf(b, "\n"); 2145 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); 2146 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n"); 2147 buf_printf(b, "\n"); 2148 buf_printf(b, "__visible struct module __this_module\n"); 2149 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n"); 2150 buf_printf(b, "\t.name = KBUILD_MODNAME,\n"); 2151 if (mod->has_init) 2152 buf_printf(b, "\t.init = init_module,\n"); 2153 if (mod->has_cleanup) 2154 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" 2155 "\t.exit = cleanup_module,\n" 2156 "#endif\n"); 2157 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n"); 2158 buf_printf(b, "};\n"); 2159 } 2160 2161 static void add_intree_flag(struct buffer *b, int is_intree) 2162 { 2163 if (is_intree) 2164 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); 2165 } 2166 2167 /* Cannot check for assembler */ 2168 static void add_retpoline(struct buffer *b) 2169 { 2170 buf_printf(b, "\n#ifdef RETPOLINE\n"); 2171 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n"); 2172 buf_printf(b, "#endif\n"); 2173 } 2174 2175 static void add_staging_flag(struct buffer *b, const char *name) 2176 { 2177 static const char *staging_dir = "drivers/staging"; 2178 2179 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0) 2180 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); 2181 } 2182 2183 /** 2184 * Record CRCs for unresolved symbols 2185 **/ 2186 static int add_versions(struct buffer *b, struct module *mod) 2187 { 2188 struct symbol *s, *exp; 2189 int err = 0; 2190 2191 for (s = mod->unres; s; s = s->next) { 2192 exp = find_symbol(s->name); 2193 if (!exp || exp->module == mod) { 2194 if (have_vmlinux && !s->weak) { 2195 if (warn_unresolved) { 2196 warn("\"%s\" [%s.ko] undefined!\n", 2197 s->name, mod->name); 2198 } else { 2199 merror("\"%s\" [%s.ko] undefined!\n", 2200 s->name, mod->name); 2201 err = 1; 2202 } 2203 } 2204 continue; 2205 } 2206 s->module = exp->module; 2207 s->crc_valid = exp->crc_valid; 2208 s->crc = exp->crc; 2209 } 2210 2211 if (!modversions) 2212 return err; 2213 2214 buf_printf(b, "\n"); 2215 buf_printf(b, "static const struct modversion_info ____versions[]\n"); 2216 buf_printf(b, "__used\n"); 2217 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n"); 2218 2219 for (s = mod->unres; s; s = s->next) { 2220 if (!s->module) 2221 continue; 2222 if (!s->crc_valid) { 2223 warn("\"%s\" [%s.ko] has no CRC!\n", 2224 s->name, mod->name); 2225 continue; 2226 } 2227 if (strlen(s->name) >= MODULE_NAME_LEN) { 2228 merror("too long symbol \"%s\" [%s.ko]\n", 2229 s->name, mod->name); 2230 err = 1; 2231 break; 2232 } 2233 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n", 2234 s->crc, s->name); 2235 } 2236 2237 buf_printf(b, "};\n"); 2238 2239 return err; 2240 } 2241 2242 static void add_depends(struct buffer *b, struct module *mod, 2243 struct module *modules) 2244 { 2245 struct symbol *s; 2246 struct module *m; 2247 int first = 1; 2248 2249 for (m = modules; m; m = m->next) 2250 m->seen = is_vmlinux(m->name); 2251 2252 buf_printf(b, "\n"); 2253 buf_printf(b, "static const char __module_depends[]\n"); 2254 buf_printf(b, "__used\n"); 2255 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n"); 2256 buf_printf(b, "\"depends="); 2257 for (s = mod->unres; s; s = s->next) { 2258 const char *p; 2259 if (!s->module) 2260 continue; 2261 2262 if (s->module->seen) 2263 continue; 2264 2265 s->module->seen = 1; 2266 p = strrchr(s->module->name, '/'); 2267 if (p) 2268 p++; 2269 else 2270 p = s->module->name; 2271 buf_printf(b, "%s%s", first ? "" : ",", p); 2272 first = 0; 2273 } 2274 buf_printf(b, "\";\n"); 2275 } 2276 2277 static void add_srcversion(struct buffer *b, struct module *mod) 2278 { 2279 if (mod->srcversion[0]) { 2280 buf_printf(b, "\n"); 2281 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", 2282 mod->srcversion); 2283 } 2284 } 2285 2286 static void write_if_changed(struct buffer *b, const char *fname) 2287 { 2288 char *tmp; 2289 FILE *file; 2290 struct stat st; 2291 2292 file = fopen(fname, "r"); 2293 if (!file) 2294 goto write; 2295 2296 if (fstat(fileno(file), &st) < 0) 2297 goto close_write; 2298 2299 if (st.st_size != b->pos) 2300 goto close_write; 2301 2302 tmp = NOFAIL(malloc(b->pos)); 2303 if (fread(tmp, 1, b->pos, file) != b->pos) 2304 goto free_write; 2305 2306 if (memcmp(tmp, b->p, b->pos) != 0) 2307 goto free_write; 2308 2309 free(tmp); 2310 fclose(file); 2311 return; 2312 2313 free_write: 2314 free(tmp); 2315 close_write: 2316 fclose(file); 2317 write: 2318 file = fopen(fname, "w"); 2319 if (!file) { 2320 perror(fname); 2321 exit(1); 2322 } 2323 if (fwrite(b->p, 1, b->pos, file) != b->pos) { 2324 perror(fname); 2325 exit(1); 2326 } 2327 fclose(file); 2328 } 2329 2330 /* parse Module.symvers file. line format: 2331 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something] 2332 **/ 2333 static void read_dump(const char *fname, unsigned int kernel) 2334 { 2335 unsigned long size, pos = 0; 2336 void *file = grab_file(fname, &size); 2337 char *line; 2338 2339 if (!file) 2340 /* No symbol versions, silently ignore */ 2341 return; 2342 2343 while ((line = get_next_line(&pos, file, size))) { 2344 char *symname, *modname, *d, *export, *end; 2345 unsigned int crc; 2346 struct module *mod; 2347 struct symbol *s; 2348 2349 if (!(symname = strchr(line, '\t'))) 2350 goto fail; 2351 *symname++ = '\0'; 2352 if (!(modname = strchr(symname, '\t'))) 2353 goto fail; 2354 *modname++ = '\0'; 2355 if ((export = strchr(modname, '\t')) != NULL) 2356 *export++ = '\0'; 2357 if (export && ((end = strchr(export, '\t')) != NULL)) 2358 *end = '\0'; 2359 crc = strtoul(line, &d, 16); 2360 if (*symname == '\0' || *modname == '\0' || *d != '\0') 2361 goto fail; 2362 mod = find_module(modname); 2363 if (!mod) { 2364 if (is_vmlinux(modname)) 2365 have_vmlinux = 1; 2366 mod = new_module(modname); 2367 mod->skip = 1; 2368 } 2369 s = sym_add_exported(symname, mod, export_no(export)); 2370 s->kernel = kernel; 2371 s->preloaded = 1; 2372 sym_update_crc(symname, mod, crc, export_no(export)); 2373 } 2374 release_file(file, size); 2375 return; 2376 fail: 2377 release_file(file, size); 2378 fatal("parse error in symbol dump file\n"); 2379 } 2380 2381 /* For normal builds always dump all symbols. 2382 * For external modules only dump symbols 2383 * that are not read from kernel Module.symvers. 2384 **/ 2385 static int dump_sym(struct symbol *sym) 2386 { 2387 if (!external_module) 2388 return 1; 2389 if (sym->vmlinux || sym->kernel) 2390 return 0; 2391 return 1; 2392 } 2393 2394 static void write_dump(const char *fname) 2395 { 2396 struct buffer buf = { }; 2397 struct symbol *symbol; 2398 int n; 2399 2400 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { 2401 symbol = symbolhash[n]; 2402 while (symbol) { 2403 if (dump_sym(symbol)) 2404 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n", 2405 symbol->crc, symbol->name, 2406 symbol->module->name, 2407 export_str(symbol->export)); 2408 symbol = symbol->next; 2409 } 2410 } 2411 write_if_changed(&buf, fname); 2412 free(buf.p); 2413 } 2414 2415 struct ext_sym_list { 2416 struct ext_sym_list *next; 2417 const char *file; 2418 }; 2419 2420 int main(int argc, char **argv) 2421 { 2422 struct module *mod; 2423 struct buffer buf = { }; 2424 char *kernel_read = NULL, *module_read = NULL; 2425 char *dump_write = NULL, *files_source = NULL; 2426 int opt; 2427 int err; 2428 struct ext_sym_list *extsym_iter; 2429 struct ext_sym_list *extsym_start = NULL; 2430 2431 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) { 2432 switch (opt) { 2433 case 'i': 2434 kernel_read = optarg; 2435 break; 2436 case 'I': 2437 module_read = optarg; 2438 external_module = 1; 2439 break; 2440 case 'e': 2441 external_module = 1; 2442 extsym_iter = 2443 NOFAIL(malloc(sizeof(*extsym_iter))); 2444 extsym_iter->next = extsym_start; 2445 extsym_iter->file = optarg; 2446 extsym_start = extsym_iter; 2447 break; 2448 case 'm': 2449 modversions = 1; 2450 break; 2451 case 'n': 2452 ignore_missing_files = 1; 2453 break; 2454 case 'o': 2455 dump_write = optarg; 2456 break; 2457 case 'a': 2458 all_versions = 1; 2459 break; 2460 case 's': 2461 vmlinux_section_warnings = 0; 2462 break; 2463 case 'S': 2464 sec_mismatch_verbose = 0; 2465 break; 2466 case 'T': 2467 files_source = optarg; 2468 break; 2469 case 'w': 2470 warn_unresolved = 1; 2471 break; 2472 case 'E': 2473 sec_mismatch_fatal = 1; 2474 break; 2475 default: 2476 exit(1); 2477 } 2478 } 2479 2480 if (kernel_read) 2481 read_dump(kernel_read, 1); 2482 if (module_read) 2483 read_dump(module_read, 0); 2484 while (extsym_start) { 2485 read_dump(extsym_start->file, 0); 2486 extsym_iter = extsym_start->next; 2487 free(extsym_start); 2488 extsym_start = extsym_iter; 2489 } 2490 2491 while (optind < argc) 2492 read_symbols(argv[optind++]); 2493 2494 if (files_source) 2495 read_symbols_from_files(files_source); 2496 2497 for (mod = modules; mod; mod = mod->next) { 2498 if (mod->skip) 2499 continue; 2500 check_exports(mod); 2501 } 2502 2503 err = 0; 2504 2505 for (mod = modules; mod; mod = mod->next) { 2506 char fname[PATH_MAX]; 2507 2508 if (mod->skip) 2509 continue; 2510 2511 buf.pos = 0; 2512 2513 err |= check_modname_len(mod); 2514 add_header(&buf, mod); 2515 add_intree_flag(&buf, !external_module); 2516 add_retpoline(&buf); 2517 add_staging_flag(&buf, mod->name); 2518 err |= add_versions(&buf, mod); 2519 add_depends(&buf, mod, modules); 2520 add_moddevtable(&buf, mod); 2521 add_srcversion(&buf, mod); 2522 2523 sprintf(fname, "%s.mod.c", mod->name); 2524 write_if_changed(&buf, fname); 2525 } 2526 if (dump_write) 2527 write_dump(dump_write); 2528 if (sec_mismatch_count) { 2529 if (!sec_mismatch_verbose) { 2530 warn("modpost: Found %d section mismatch(es).\n" 2531 "To see full details build your kernel with:\n" 2532 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n", 2533 sec_mismatch_count); 2534 } 2535 if (sec_mismatch_fatal) { 2536 fatal("modpost: Section mismatches detected.\n" 2537 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); 2538 } 2539 } 2540 free(buf.p); 2541 2542 return err; 2543 } 2544