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 <stdint.h> 34 #include <string.h> 35 #include <machine/elf.h> 36 #include <stand.h> 37 #define FREEBSD_ELF 38 #include <sys/link_elf.h> 39 40 #include "bootstrap.h" 41 42 #define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l) 43 44 #if defined(__i386__) && __ELF_WORD_SIZE == 64 45 #undef ELF_TARG_CLASS 46 #undef ELF_TARG_MACH 47 #define ELF_TARG_CLASS ELFCLASS64 48 #define ELF_TARG_MACH EM_X86_64 49 #endif 50 51 typedef struct elf_file { 52 Elf_Ehdr hdr; 53 Elf_Shdr *e_shdr; 54 55 int symtabindex; /* Index of symbol table */ 56 int shstrindex; /* Index of section name string table */ 57 58 int fd; 59 vm_offset_t off; 60 #ifdef LOADER_VERIEXEC_VECTX 61 struct vectx *vctx; 62 #endif 63 } *elf_file_t; 64 65 #ifdef LOADER_VERIEXEC_VECTX 66 #define VECTX_HANDLE(ef) (ef)->vctx 67 #else 68 #define VECTX_HANDLE(ef) (ef)->fd 69 #endif 70 71 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef, 72 uint64_t loadaddr); 73 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef, 74 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp); 75 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, 76 Elf_Addr p, void *val, size_t len); 77 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp, 78 elf_file_t ef); 79 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx); 80 81 const char *__elfN(obj_kerneltype) = "elf kernel"; 82 const char *__elfN(obj_moduletype) = "elf obj module"; 83 84 /* 85 * Attempt to load the file (file) as an ELF module. It will be stored at 86 * (dest), and a pointer to a module structure describing the loaded object 87 * will be saved in (result). 88 */ 89 int 90 __elfN(obj_loadfile)(char *filename, uint64_t dest, 91 struct preloaded_file **result) 92 { 93 struct preloaded_file *fp, *kfp; 94 struct elf_file ef; 95 Elf_Ehdr *hdr; 96 int err; 97 ssize_t bytes_read; 98 99 fp = NULL; 100 bzero(&ef, sizeof(struct elf_file)); 101 102 /* 103 * Open the image, read and validate the ELF header 104 */ 105 if (filename == NULL) /* can't handle nameless */ 106 return(EFTYPE); 107 if ((ef.fd = open(filename, O_RDONLY)) == -1) 108 return(errno); 109 #ifdef LOADER_VERIEXEC_VECTX 110 { 111 int verror; 112 113 ef.vctx = vectx_open(ef.fd, filename, 0L, NULL, &verror, __func__); 114 if (verror) { 115 printf("Unverified %s: %s\n", filename, ve_error_get()); 116 close(ef.fd); 117 free(ef.vctx); 118 return (EAUTH); 119 } 120 } 121 #endif 122 123 hdr = &ef.hdr; 124 bytes_read = VECTX_READ(VECTX_HANDLE(&ef), hdr, sizeof(*hdr)); 125 if (bytes_read != sizeof(*hdr)) { 126 err = EFTYPE; /* could be EIO, but may be small file */ 127 goto oerr; 128 } 129 130 /* Is it ELF? */ 131 if (!IS_ELF(*hdr)) { 132 err = EFTYPE; 133 goto oerr; 134 } 135 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */ 136 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 137 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */ 138 hdr->e_version != EV_CURRENT || 139 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */ 140 hdr->e_type != ET_REL) { 141 err = EFTYPE; 142 goto oerr; 143 } 144 145 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 || 146 hdr->e_shentsize != sizeof(Elf_Shdr)) { 147 err = EFTYPE; 148 goto oerr; 149 } 150 151 #if defined(LOADER_VERIEXEC) && !defined(LOADER_VERIEXEC_VECTX) 152 if (verify_file(ef.fd, filename, bytes_read, VE_MUST, __func__) < 0) { 153 err = EAUTH; 154 goto oerr; 155 } 156 #endif 157 158 kfp = file_findfile(NULL, __elfN(obj_kerneltype)); 159 if (kfp == NULL) { 160 printf("elf" __XSTRING(__ELF_WORD_SIZE) 161 "_obj_loadfile: can't load module before kernel\n"); 162 err = EPERM; 163 goto oerr; 164 } 165 166 if (archsw.arch_loadaddr != NULL) 167 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest); 168 else 169 dest = roundup(dest, PAGE_SIZE); 170 171 /* 172 * Ok, we think we should handle this. 173 */ 174 fp = file_alloc(); 175 if (fp == NULL) { 176 printf("elf" __XSTRING(__ELF_WORD_SIZE) 177 "_obj_loadfile: cannot allocate module info\n"); 178 err = EPERM; 179 goto out; 180 } 181 fp->f_name = strdup(filename); 182 fp->f_type = strdup(__elfN(obj_moduletype)); 183 184 if (module_verbose > MODULE_VERBOSE_SILENT) 185 printf("%s ", filename); 186 187 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest); 188 if (fp->f_size == 0 || fp->f_addr == 0) 189 goto ioerr; 190 191 /* save exec header as metadata */ 192 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr); 193 194 /* Load OK, return module pointer */ 195 *result = (struct preloaded_file *)fp; 196 err = 0; 197 goto out; 198 199 ioerr: 200 err = EIO; 201 oerr: 202 file_discard(fp); 203 out: 204 #ifdef LOADER_VERIEXEC_VECTX 205 if (!err && ef.vctx) { 206 int verror; 207 208 verror = vectx_close(ef.vctx, VE_MUST, __func__); 209 if (verror) { 210 err = EAUTH; 211 file_discard(fp); 212 } 213 } 214 #endif 215 close(ef.fd); 216 if (ef.e_shdr != NULL) 217 free(ef.e_shdr); 218 219 return(err); 220 } 221 222 /* 223 * With the file (fd) open on the image, and (ehdr) containing 224 * the Elf header, load the image at (off) 225 */ 226 static int 227 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off) 228 { 229 Elf_Ehdr *hdr; 230 Elf_Shdr *shdr, *cshdr, *lshdr; 231 vm_offset_t firstaddr, lastaddr; 232 int i, nsym, res, ret, shdrbytes, symstrindex; 233 234 ret = 0; 235 firstaddr = lastaddr = (vm_offset_t)off; 236 hdr = &ef->hdr; 237 ef->off = (vm_offset_t)off; 238 239 /* Read in the section headers. */ 240 shdrbytes = hdr->e_shnum * hdr->e_shentsize; 241 shdr = alloc_pread(VECTX_HANDLE(ef), (off_t)hdr->e_shoff, shdrbytes); 242 if (shdr == NULL) { 243 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 244 "_obj_loadimage: read section headers failed\n"); 245 goto out; 246 } 247 ef->e_shdr = shdr; 248 249 /* 250 * Decide where to load everything, but don't read it yet. 251 * We store the load address as a non-zero sh_addr value. 252 * Start with the code/data and bss. 253 */ 254 for (i = 0; i < hdr->e_shnum; i++) 255 shdr[i].sh_addr = 0; 256 for (i = 0; i < hdr->e_shnum; i++) { 257 if (shdr[i].sh_size == 0) 258 continue; 259 switch (shdr[i].sh_type) { 260 case SHT_PROGBITS: 261 case SHT_NOBITS: 262 #if defined(__i386__) || defined(__amd64__) 263 case SHT_X86_64_UNWIND: 264 #endif 265 case SHT_INIT_ARRAY: 266 case SHT_FINI_ARRAY: 267 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 268 break; 269 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 270 shdr[i].sh_addr = (Elf_Addr)lastaddr; 271 lastaddr += shdr[i].sh_size; 272 break; 273 } 274 } 275 276 /* Symbols. */ 277 nsym = 0; 278 for (i = 0; i < hdr->e_shnum; i++) { 279 switch (shdr[i].sh_type) { 280 case SHT_SYMTAB: 281 nsym++; 282 ef->symtabindex = i; 283 break; 284 } 285 } 286 if (nsym != 1) { 287 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 288 "_obj_loadimage: file has no valid symbol table\n"); 289 goto out; 290 } 291 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign); 292 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr; 293 lastaddr += shdr[ef->symtabindex].sh_size; 294 295 symstrindex = shdr[ef->symtabindex].sh_link; 296 if (symstrindex < 0 || symstrindex >= hdr->e_shnum || 297 shdr[symstrindex].sh_type != SHT_STRTAB) { 298 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 299 "_obj_loadimage: file has invalid symbol strings\n"); 300 goto out; 301 } 302 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign); 303 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr; 304 lastaddr += shdr[symstrindex].sh_size; 305 306 /* Section names. */ 307 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum || 308 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { 309 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 310 "_obj_loadimage: file has no section names\n"); 311 goto out; 312 } 313 ef->shstrindex = hdr->e_shstrndx; 314 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign); 315 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr; 316 lastaddr += shdr[ef->shstrindex].sh_size; 317 318 /* Relocation tables. */ 319 for (i = 0; i < hdr->e_shnum; i++) { 320 switch (shdr[i].sh_type) { 321 case SHT_REL: 322 case SHT_RELA: 323 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 324 break; 325 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 326 shdr[i].sh_addr = (Elf_Addr)lastaddr; 327 lastaddr += shdr[i].sh_size; 328 break; 329 } 330 } 331 332 /* Clear the whole area, including bss regions. */ 333 kern_bzero(firstaddr, lastaddr - firstaddr); 334 335 /* Figure section with the lowest file offset we haven't loaded yet. */ 336 for (cshdr = NULL; /* none */; /* none */) 337 { 338 /* 339 * Find next section to load. The complexity of this loop is 340 * O(n^2), but with the number of sections being typically 341 * small, we do not care. 342 */ 343 lshdr = cshdr; 344 345 for (i = 0; i < hdr->e_shnum; i++) { 346 if (shdr[i].sh_addr == 0 || 347 shdr[i].sh_type == SHT_NOBITS) 348 continue; 349 /* Skip sections that were loaded already. */ 350 if (lshdr != NULL && 351 lshdr->sh_offset >= shdr[i].sh_offset) 352 continue; 353 /* Find section with smallest offset. */ 354 if (cshdr == lshdr || 355 cshdr->sh_offset > shdr[i].sh_offset) 356 cshdr = &shdr[i]; 357 } 358 359 if (cshdr == lshdr) 360 break; 361 362 if (kern_pread(VECTX_HANDLE(ef), (vm_offset_t)cshdr->sh_addr, 363 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) { 364 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 365 "_obj_loadimage: read failed\n"); 366 goto out; 367 } 368 } 369 370 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr); 371 372 res = __elfN(obj_parse_modmetadata)(fp, ef); 373 if (res != 0) 374 goto out; 375 376 ret = lastaddr - firstaddr; 377 fp->f_addr = firstaddr; 378 379 if (module_verbose > MODULE_VERBOSE_SILENT) 380 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr); 381 382 out: 383 if (module_verbose > MODULE_VERBOSE_SILENT) 384 printf("\n"); 385 return ret; 386 } 387 388 #if defined(__i386__) && __ELF_WORD_SIZE == 64 389 struct mod_metadata64 { 390 int md_version; /* structure version MDTV_* */ 391 int md_type; /* type of entry MDT_* */ 392 uint64_t md_data; /* specific data */ 393 uint64_t md_cval; /* common string label */ 394 }; 395 #endif 396 397 int 398 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef) 399 { 400 struct mod_metadata md; 401 #if defined(__i386__) && __ELF_WORD_SIZE == 64 402 struct mod_metadata64 md64; 403 #endif 404 struct mod_depend *mdepend; 405 struct mod_version mver; 406 char *s; 407 int error, modcnt, minfolen; 408 Elf_Addr v, p, p_stop; 409 410 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop, 411 &modcnt) != 0) 412 return 0; 413 414 modcnt = 0; 415 while (p < p_stop) { 416 COPYOUT(p, &v, sizeof(v)); 417 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v)); 418 if (error != 0) 419 return (error); 420 #if defined(__i386__) && __ELF_WORD_SIZE == 64 421 COPYOUT(v, &md64, sizeof(md64)); 422 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64)); 423 if (error != 0) 424 return (error); 425 md.md_version = md64.md_version; 426 md.md_type = md64.md_type; 427 md.md_cval = (const char *)(uintptr_t)md64.md_cval; 428 md.md_data = (void *)(uintptr_t)md64.md_data; 429 #else 430 COPYOUT(v, &md, sizeof(md)); 431 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md)); 432 if (error != 0) 433 return (error); 434 #endif 435 p += sizeof(Elf_Addr); 436 switch(md.md_type) { 437 case MDT_DEPEND: 438 s = strdupout((vm_offset_t)md.md_cval); 439 minfolen = sizeof(*mdepend) + strlen(s) + 1; 440 mdepend = malloc(minfolen); 441 if (mdepend == NULL) 442 return ENOMEM; 443 COPYOUT((vm_offset_t)md.md_data, mdepend, 444 sizeof(*mdepend)); 445 strcpy((char*)(mdepend + 1), s); 446 free(s); 447 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen, 448 mdepend); 449 free(mdepend); 450 break; 451 case MDT_VERSION: 452 s = strdupout((vm_offset_t)md.md_cval); 453 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver)); 454 file_addmodule(fp, s, mver.mv_version, NULL); 455 free(s); 456 modcnt++; 457 break; 458 case MDT_MODULE: 459 case MDT_PNP_INFO: 460 break; 461 default: 462 printf("unknown type %d\n", md.md_type); 463 break; 464 } 465 } 466 return 0; 467 } 468 469 static int 470 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef, 471 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp) 472 { 473 Elf_Ehdr *hdr; 474 Elf_Shdr *shdr; 475 char *p; 476 vm_offset_t shstrtab; 477 int i; 478 479 hdr = &ef->hdr; 480 shdr = ef->e_shdr; 481 shstrtab = shdr[ef->shstrindex].sh_addr; 482 483 for (i = 0; i < hdr->e_shnum; i++) { 484 if (shdr[i].sh_type != SHT_PROGBITS) 485 continue; 486 if (shdr[i].sh_name == 0) 487 continue; 488 p = strdupout(shstrtab + shdr[i].sh_name); 489 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) { 490 *startp = shdr[i].sh_addr; 491 *stopp = shdr[i].sh_addr + shdr[i].sh_size; 492 *countp = (*stopp - *startp) / sizeof(Elf_Addr); 493 free(p); 494 return (0); 495 } 496 free(p); 497 } 498 499 return (ESRCH); 500 } 501 502 /* 503 * Apply any intra-module relocations to the value. p is the load address 504 * of the value and val/len is the value to be modified. This does NOT modify 505 * the image in-place, because this is done by kern_linker later on. 506 */ 507 static int 508 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p, 509 void *val, size_t len) 510 { 511 Elf_Ehdr *hdr; 512 Elf_Shdr *shdr; 513 Elf_Addr off = p; 514 Elf_Addr base; 515 Elf_Rela a, *abase; 516 Elf_Rel r, *rbase; 517 int error, i, j, nrel, nrela; 518 519 hdr = &ef->hdr; 520 shdr = ef->e_shdr; 521 522 for (i = 0; i < hdr->e_shnum; i++) { 523 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL) 524 continue; 525 base = shdr[shdr[i].sh_info].sh_addr; 526 if (base == 0 || shdr[i].sh_addr == 0) 527 continue; 528 if (off < base || off + len > base + 529 shdr[shdr[i].sh_info].sh_size) 530 continue; 531 532 switch (shdr[i].sh_type) { 533 case SHT_RELA: 534 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr; 535 536 nrela = shdr[i].sh_size / sizeof(Elf_Rela); 537 for (j = 0; j < nrela; j++) { 538 COPYOUT(abase + j, &a, sizeof(a)); 539 540 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 541 &a, ELF_RELOC_RELA, base, off, val, len); 542 if (error != 0) 543 return (error); 544 } 545 break; 546 case SHT_REL: 547 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr; 548 549 nrel = shdr[i].sh_size / sizeof(Elf_Rel); 550 for (j = 0; j < nrel; j++) { 551 COPYOUT(rbase + j, &r, sizeof(r)); 552 553 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 554 &r, ELF_RELOC_REL, base, off, val, len); 555 if (error != 0) 556 return (error); 557 } 558 break; 559 } 560 } 561 return (0); 562 } 563 564 /* Look up the address of a specified symbol. */ 565 static Elf_Addr 566 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx) 567 { 568 Elf_Sym sym; 569 Elf_Addr base; 570 571 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym)) 572 return (0); 573 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym), 574 &sym, sizeof(sym)); 575 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum) 576 return (0); 577 base = ef->e_shdr[sym.st_shndx].sh_addr; 578 if (base == 0) 579 return (0); 580 return (base + sym.st_value); 581 } 582