1 /*- 2 * Copyright (c) 2004 Ian Dowse <iedowse@freebsd.org> 3 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org> 4 * Copyright (c) 1998 Peter Wemm <peter@freebsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/exec.h> 31 #include <sys/linker.h> 32 #include <sys/module.h> 33 #include <machine/elf.h> 34 #include <stand.h> 35 36 #include "bootstrap.h" 37 #include "modinfo.h" 38 39 #define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l) 40 41 #if defined(__i386__) && __ELF_WORD_SIZE == 64 42 #undef ELF_TARG_CLASS 43 #undef ELF_TARG_MACH 44 #define ELF_TARG_CLASS ELFCLASS64 45 #define ELF_TARG_MACH EM_X86_64 46 #endif 47 48 typedef struct elf_file { 49 Elf_Ehdr hdr; 50 Elf_Shdr *e_shdr; 51 52 int symtabindex; /* Index of symbol table */ 53 int shstrindex; /* Index of section name string table */ 54 55 int fd; 56 vm_offset_t off; 57 #ifdef LOADER_VERIEXEC_VECTX 58 struct vectx *vctx; 59 #endif 60 } *elf_file_t; 61 62 #ifdef LOADER_VERIEXEC_VECTX 63 #define VECTX_HANDLE(ef) (ef)->vctx 64 #else 65 #define VECTX_HANDLE(ef) (ef)->fd 66 #endif 67 68 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef, 69 uint64_t loadaddr); 70 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef, 71 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp); 72 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, 73 Elf_Addr p, void *val, size_t len); 74 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp, 75 elf_file_t ef); 76 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx); 77 78 /* 79 * Attempt to load the file (file) as an ELF module. It will be stored at 80 * (dest), and a pointer to a module structure describing the loaded object 81 * will be saved in (result). 82 */ 83 int 84 __elfN(obj_loadfile)(char *filename, uint64_t dest, 85 struct preloaded_file **result) 86 { 87 struct preloaded_file *fp, *kfp; 88 struct elf_file ef; 89 Elf_Ehdr *hdr; 90 int err; 91 ssize_t bytes_read; 92 93 fp = NULL; 94 bzero(&ef, sizeof(struct elf_file)); 95 96 /* 97 * Open the image, read and validate the ELF header 98 */ 99 if (filename == NULL) /* can't handle nameless */ 100 return(EFTYPE); 101 if ((ef.fd = open(filename, O_RDONLY)) == -1) 102 return(errno); 103 #ifdef LOADER_VERIEXEC_VECTX 104 { 105 int verror; 106 107 ef.vctx = vectx_open(ef.fd, filename, 0L, NULL, &verror, __func__); 108 if (verror) { 109 printf("Unverified %s: %s\n", filename, ve_error_get()); 110 close(ef.fd); 111 free(ef.vctx); 112 return (EAUTH); 113 } 114 } 115 #endif 116 117 hdr = &ef.hdr; 118 bytes_read = VECTX_READ(VECTX_HANDLE(&ef), hdr, sizeof(*hdr)); 119 if (bytes_read != sizeof(*hdr)) { 120 err = EFTYPE; /* could be EIO, but may be small file */ 121 goto oerr; 122 } 123 124 /* Is it ELF? */ 125 if (!IS_ELF(*hdr)) { 126 err = EFTYPE; 127 goto oerr; 128 } 129 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */ 130 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 131 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */ 132 hdr->e_version != EV_CURRENT || 133 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */ 134 hdr->e_type != ET_REL) { 135 err = EFTYPE; 136 goto oerr; 137 } 138 139 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 || 140 hdr->e_shentsize != sizeof(Elf_Shdr)) { 141 err = EFTYPE; 142 goto oerr; 143 } 144 145 #if defined(LOADER_VERIEXEC) && !defined(LOADER_VERIEXEC_VECTX) 146 if (verify_file(ef.fd, filename, bytes_read, VE_MUST, __func__) < 0) { 147 err = EAUTH; 148 goto oerr; 149 } 150 #endif 151 152 kfp = file_findfile(NULL, md_kerntype); 153 if (kfp == NULL) { 154 printf("elf" __XSTRING(__ELF_WORD_SIZE) 155 "_obj_loadfile: can't load module before kernel\n"); 156 err = EPERM; 157 goto oerr; 158 } 159 160 if (archsw.arch_loadaddr != NULL) 161 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest); 162 else 163 dest = roundup(dest, PAGE_SIZE); 164 165 /* 166 * Ok, we think we should handle this. 167 */ 168 fp = file_alloc(); 169 if (fp == NULL) { 170 printf("elf" __XSTRING(__ELF_WORD_SIZE) 171 "_obj_loadfile: cannot allocate module info\n"); 172 err = EPERM; 173 goto out; 174 } 175 fp->f_name = strdup(filename); 176 fp->f_type = strdup(md_modtype_obj); 177 178 if (module_verbose > MODULE_VERBOSE_SILENT) 179 printf("%s ", filename); 180 181 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest); 182 if (fp->f_size == 0 || fp->f_addr == 0) 183 goto ioerr; 184 185 /* save exec header as metadata */ 186 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr); 187 188 /* Load OK, return module pointer */ 189 *result = (struct preloaded_file *)fp; 190 err = 0; 191 goto out; 192 193 ioerr: 194 err = EIO; 195 oerr: 196 file_discard(fp); 197 out: 198 #ifdef LOADER_VERIEXEC_VECTX 199 if (!err && ef.vctx) { 200 int verror; 201 202 verror = vectx_close(ef.vctx, VE_MUST, __func__); 203 if (verror) { 204 err = EAUTH; 205 file_discard(fp); 206 } 207 } 208 #endif 209 close(ef.fd); 210 if (ef.e_shdr != NULL) 211 free(ef.e_shdr); 212 213 return(err); 214 } 215 216 /* 217 * With the file (fd) open on the image, and (ehdr) containing 218 * the Elf header, load the image at (off) 219 */ 220 static int 221 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off) 222 { 223 Elf_Ehdr *hdr; 224 Elf_Shdr *shdr, *cshdr, *lshdr; 225 vm_offset_t firstaddr, lastaddr; 226 int i, nsym, res, ret, shdrbytes, symstrindex; 227 228 ret = 0; 229 firstaddr = lastaddr = (vm_offset_t)off; 230 hdr = &ef->hdr; 231 ef->off = (vm_offset_t)off; 232 233 /* Read in the section headers. */ 234 shdrbytes = hdr->e_shnum * hdr->e_shentsize; 235 shdr = alloc_pread(VECTX_HANDLE(ef), (off_t)hdr->e_shoff, shdrbytes); 236 if (shdr == NULL) { 237 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 238 "_obj_loadimage: read section headers failed\n"); 239 goto out; 240 } 241 ef->e_shdr = shdr; 242 243 /* 244 * Decide where to load everything, but don't read it yet. 245 * We store the load address as a non-zero sh_addr value. 246 * Start with the code/data and bss. 247 */ 248 for (i = 0; i < hdr->e_shnum; i++) 249 shdr[i].sh_addr = 0; 250 for (i = 0; i < hdr->e_shnum; i++) { 251 if (shdr[i].sh_size == 0) 252 continue; 253 switch (shdr[i].sh_type) { 254 case SHT_PROGBITS: 255 case SHT_NOBITS: 256 #if defined(__i386__) || defined(__amd64__) 257 case SHT_X86_64_UNWIND: 258 #endif 259 case SHT_INIT_ARRAY: 260 case SHT_FINI_ARRAY: 261 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 262 break; 263 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 264 shdr[i].sh_addr = (Elf_Addr)lastaddr; 265 lastaddr += shdr[i].sh_size; 266 break; 267 } 268 } 269 270 /* Symbols. */ 271 nsym = 0; 272 for (i = 0; i < hdr->e_shnum; i++) { 273 switch (shdr[i].sh_type) { 274 case SHT_SYMTAB: 275 nsym++; 276 ef->symtabindex = i; 277 break; 278 } 279 } 280 if (nsym != 1) { 281 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 282 "_obj_loadimage: file has no valid symbol table\n"); 283 goto out; 284 } 285 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign); 286 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr; 287 lastaddr += shdr[ef->symtabindex].sh_size; 288 289 symstrindex = shdr[ef->symtabindex].sh_link; 290 if (symstrindex < 0 || symstrindex >= hdr->e_shnum || 291 shdr[symstrindex].sh_type != SHT_STRTAB) { 292 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 293 "_obj_loadimage: file has invalid symbol strings\n"); 294 goto out; 295 } 296 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign); 297 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr; 298 lastaddr += shdr[symstrindex].sh_size; 299 300 /* Section names. */ 301 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum || 302 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { 303 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 304 "_obj_loadimage: file has no section names\n"); 305 goto out; 306 } 307 ef->shstrindex = hdr->e_shstrndx; 308 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign); 309 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr; 310 lastaddr += shdr[ef->shstrindex].sh_size; 311 312 /* Relocation tables. */ 313 for (i = 0; i < hdr->e_shnum; i++) { 314 switch (shdr[i].sh_type) { 315 case SHT_REL: 316 case SHT_RELA: 317 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 318 break; 319 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 320 shdr[i].sh_addr = (Elf_Addr)lastaddr; 321 lastaddr += shdr[i].sh_size; 322 break; 323 } 324 } 325 326 /* Clear the whole area, including bss regions. */ 327 kern_bzero(firstaddr, lastaddr - firstaddr); 328 329 /* Figure section with the lowest file offset we haven't loaded yet. */ 330 for (cshdr = NULL; /* none */; /* none */) 331 { 332 /* 333 * Find next section to load. The complexity of this loop is 334 * O(n^2), but with the number of sections being typically 335 * small, we do not care. 336 */ 337 lshdr = cshdr; 338 339 for (i = 0; i < hdr->e_shnum; i++) { 340 if (shdr[i].sh_addr == 0 || 341 shdr[i].sh_type == SHT_NOBITS) 342 continue; 343 /* Skip sections that were loaded already. */ 344 if (lshdr != NULL && 345 lshdr->sh_offset >= shdr[i].sh_offset) 346 continue; 347 /* Find section with smallest offset. */ 348 if (cshdr == lshdr || 349 cshdr->sh_offset > shdr[i].sh_offset) 350 cshdr = &shdr[i]; 351 } 352 353 if (cshdr == lshdr) 354 break; 355 356 if (kern_pread(VECTX_HANDLE(ef), (vm_offset_t)cshdr->sh_addr, 357 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) { 358 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 359 "_obj_loadimage: read failed\n"); 360 goto out; 361 } 362 } 363 364 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr); 365 366 res = __elfN(obj_parse_modmetadata)(fp, ef); 367 if (res != 0) 368 goto out; 369 370 ret = lastaddr - firstaddr; 371 fp->f_addr = firstaddr; 372 373 if (module_verbose > MODULE_VERBOSE_SILENT) 374 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr); 375 376 out: 377 if (module_verbose > MODULE_VERBOSE_SILENT) 378 printf("\n"); 379 return ret; 380 } 381 382 #if defined(__i386__) && __ELF_WORD_SIZE == 64 383 struct mod_metadata64 { 384 int md_version; /* structure version MDTV_* */ 385 int md_type; /* type of entry MDT_* */ 386 uint64_t md_data; /* specific data */ 387 uint64_t md_cval; /* common string label */ 388 }; 389 #endif 390 391 int 392 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef) 393 { 394 struct mod_metadata md; 395 #if defined(__i386__) && __ELF_WORD_SIZE == 64 396 struct mod_metadata64 md64; 397 #endif 398 struct mod_depend *mdepend; 399 struct mod_version mver; 400 char *s; 401 int error, modcnt, minfolen; 402 Elf_Addr v, p, p_stop; 403 404 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop, 405 &modcnt) != 0) 406 return 0; 407 408 modcnt = 0; 409 while (p < p_stop) { 410 COPYOUT(p, &v, sizeof(v)); 411 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v)); 412 if (error != 0) 413 return (error); 414 #if defined(__i386__) && __ELF_WORD_SIZE == 64 415 COPYOUT(v, &md64, sizeof(md64)); 416 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64)); 417 if (error != 0) 418 return (error); 419 md.md_version = md64.md_version; 420 md.md_type = md64.md_type; 421 md.md_cval = (const char *)(uintptr_t)md64.md_cval; 422 md.md_data = (void *)(uintptr_t)md64.md_data; 423 #else 424 COPYOUT(v, &md, sizeof(md)); 425 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md)); 426 if (error != 0) 427 return (error); 428 #endif 429 p += sizeof(Elf_Addr); 430 switch(md.md_type) { 431 case MDT_DEPEND: 432 s = strdupout((vm_offset_t)md.md_cval); 433 minfolen = sizeof(*mdepend) + strlen(s) + 1; 434 mdepend = malloc(minfolen); 435 if (mdepend == NULL) 436 return ENOMEM; 437 COPYOUT((vm_offset_t)md.md_data, mdepend, 438 sizeof(*mdepend)); 439 strcpy((char*)(mdepend + 1), s); 440 free(s); 441 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen, 442 mdepend); 443 free(mdepend); 444 break; 445 case MDT_VERSION: 446 s = strdupout((vm_offset_t)md.md_cval); 447 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver)); 448 file_addmodule(fp, s, mver.mv_version, NULL); 449 free(s); 450 modcnt++; 451 break; 452 case MDT_MODULE: 453 case MDT_PNP_INFO: 454 break; 455 default: 456 printf("unknown type %d\n", md.md_type); 457 break; 458 } 459 } 460 return 0; 461 } 462 463 static int 464 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef, 465 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp) 466 { 467 Elf_Ehdr *hdr; 468 Elf_Shdr *shdr; 469 char *p; 470 vm_offset_t shstrtab; 471 int i; 472 473 hdr = &ef->hdr; 474 shdr = ef->e_shdr; 475 shstrtab = shdr[ef->shstrindex].sh_addr; 476 477 for (i = 0; i < hdr->e_shnum; i++) { 478 if (shdr[i].sh_type != SHT_PROGBITS) 479 continue; 480 if (shdr[i].sh_name == 0) 481 continue; 482 p = strdupout(shstrtab + shdr[i].sh_name); 483 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) { 484 *startp = shdr[i].sh_addr; 485 *stopp = shdr[i].sh_addr + shdr[i].sh_size; 486 *countp = (*stopp - *startp) / sizeof(Elf_Addr); 487 free(p); 488 return (0); 489 } 490 free(p); 491 } 492 493 return (ESRCH); 494 } 495 496 /* 497 * Apply any intra-module relocations to the value. p is the load address 498 * of the value and val/len is the value to be modified. This does NOT modify 499 * the image in-place, because this is done by kern_linker later on. 500 */ 501 static int 502 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p, 503 void *val, size_t len) 504 { 505 Elf_Ehdr *hdr; 506 Elf_Shdr *shdr; 507 Elf_Addr off = p; 508 Elf_Addr base; 509 Elf_Rela a, *abase; 510 Elf_Rel r, *rbase; 511 int error, i, j, nrel, nrela; 512 513 hdr = &ef->hdr; 514 shdr = ef->e_shdr; 515 516 for (i = 0; i < hdr->e_shnum; i++) { 517 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL) 518 continue; 519 base = shdr[shdr[i].sh_info].sh_addr; 520 if (base == 0 || shdr[i].sh_addr == 0) 521 continue; 522 if (off < base || off + len > base + 523 shdr[shdr[i].sh_info].sh_size) 524 continue; 525 526 switch (shdr[i].sh_type) { 527 case SHT_RELA: 528 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr; 529 530 nrela = shdr[i].sh_size / sizeof(Elf_Rela); 531 for (j = 0; j < nrela; j++) { 532 COPYOUT(abase + j, &a, sizeof(a)); 533 534 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 535 &a, ELF_RELOC_RELA, base, off, val, len); 536 if (error != 0) 537 return (error); 538 } 539 break; 540 case SHT_REL: 541 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr; 542 543 nrel = shdr[i].sh_size / sizeof(Elf_Rel); 544 for (j = 0; j < nrel; j++) { 545 COPYOUT(rbase + j, &r, sizeof(r)); 546 547 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 548 &r, ELF_RELOC_REL, base, off, val, len); 549 if (error != 0) 550 return (error); 551 } 552 break; 553 } 554 } 555 return (0); 556 } 557 558 /* Look up the address of a specified symbol. */ 559 static Elf_Addr 560 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx) 561 { 562 Elf_Sym sym; 563 Elf_Addr base; 564 565 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym)) 566 return (0); 567 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym), 568 &sym, sizeof(sym)); 569 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum) 570 return (0); 571 base = ef->e_shdr[sym.st_shndx].sh_addr; 572 if (base == 0) 573 return (0); 574 return (base + sym.st_value); 575 } 576