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/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/exec.h> 34 #include <sys/linker.h> 35 #include <sys/module.h> 36 #include <stdint.h> 37 #include <string.h> 38 #include <machine/elf.h> 39 #include <stand.h> 40 #define FREEBSD_ELF 41 #include <sys/link_elf.h> 42 43 #include "bootstrap.h" 44 45 #define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l) 46 47 #if defined(__i386__) && __ELF_WORD_SIZE == 64 48 #undef ELF_TARG_CLASS 49 #undef ELF_TARG_MACH 50 #define ELF_TARG_CLASS ELFCLASS64 51 #define ELF_TARG_MACH EM_X86_64 52 #endif 53 54 typedef struct elf_file { 55 Elf_Ehdr hdr; 56 Elf_Shdr *e_shdr; 57 58 int symtabindex; /* Index of symbol table */ 59 int shstrindex; /* Index of section name string table */ 60 61 int fd; 62 vm_offset_t off; 63 #ifdef LOADER_VERIEXEC_VECTX 64 struct vectx *vctx; 65 #endif 66 } *elf_file_t; 67 68 #ifdef LOADER_VERIEXEC_VECTX 69 #define VECTX_HANDLE(ef) (ef)->vctx 70 #else 71 #define VECTX_HANDLE(ef) (ef)->fd 72 #endif 73 74 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef, 75 uint64_t loadaddr); 76 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef, 77 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp); 78 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, 79 Elf_Addr p, void *val, size_t len); 80 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp, 81 elf_file_t ef); 82 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx); 83 84 const char *__elfN(obj_kerneltype) = "elf kernel"; 85 const char *__elfN(obj_moduletype) = "elf obj module"; 86 87 /* 88 * Attempt to load the file (file) as an ELF module. It will be stored at 89 * (dest), and a pointer to a module structure describing the loaded object 90 * will be saved in (result). 91 */ 92 int 93 __elfN(obj_loadfile)(char *filename, uint64_t dest, 94 struct preloaded_file **result) 95 { 96 struct preloaded_file *fp, *kfp; 97 struct elf_file ef; 98 Elf_Ehdr *hdr; 99 int err; 100 ssize_t bytes_read; 101 102 fp = NULL; 103 bzero(&ef, sizeof(struct elf_file)); 104 105 /* 106 * Open the image, read and validate the ELF header 107 */ 108 if (filename == NULL) /* can't handle nameless */ 109 return(EFTYPE); 110 if ((ef.fd = open(filename, O_RDONLY)) == -1) 111 return(errno); 112 #ifdef LOADER_VERIEXEC_VECTX 113 { 114 int verror; 115 116 ef.vctx = vectx_open(ef.fd, filename, 0L, NULL, &verror, __func__); 117 if (verror) { 118 printf("Unverified %s: %s\n", filename, ve_error_get()); 119 close(ef.fd); 120 free(ef.vctx); 121 return (EAUTH); 122 } 123 } 124 #endif 125 126 hdr = &ef.hdr; 127 bytes_read = VECTX_READ(VECTX_HANDLE(&ef), hdr, sizeof(*hdr)); 128 if (bytes_read != sizeof(*hdr)) { 129 err = EFTYPE; /* could be EIO, but may be small file */ 130 goto oerr; 131 } 132 133 /* Is it ELF? */ 134 if (!IS_ELF(*hdr)) { 135 err = EFTYPE; 136 goto oerr; 137 } 138 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */ 139 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 140 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */ 141 hdr->e_version != EV_CURRENT || 142 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */ 143 hdr->e_type != ET_REL) { 144 err = EFTYPE; 145 goto oerr; 146 } 147 148 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 || 149 hdr->e_shentsize != sizeof(Elf_Shdr)) { 150 err = EFTYPE; 151 goto oerr; 152 } 153 154 #if defined(LOADER_VERIEXEC) && !defined(LOADER_VERIEXEC_VECTX) 155 if (verify_file(ef.fd, filename, bytes_read, VE_MUST, __func__) < 0) { 156 err = EAUTH; 157 goto oerr; 158 } 159 #endif 160 161 kfp = file_findfile(NULL, __elfN(obj_kerneltype)); 162 if (kfp == NULL) { 163 printf("elf" __XSTRING(__ELF_WORD_SIZE) 164 "_obj_loadfile: can't load module before kernel\n"); 165 err = EPERM; 166 goto oerr; 167 } 168 169 if (archsw.arch_loadaddr != NULL) 170 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest); 171 else 172 dest = roundup(dest, PAGE_SIZE); 173 174 /* 175 * Ok, we think we should handle this. 176 */ 177 fp = file_alloc(); 178 if (fp == NULL) { 179 printf("elf" __XSTRING(__ELF_WORD_SIZE) 180 "_obj_loadfile: cannot allocate module info\n"); 181 err = EPERM; 182 goto out; 183 } 184 fp->f_name = strdup(filename); 185 fp->f_type = strdup(__elfN(obj_moduletype)); 186 187 if (module_verbose > MODULE_VERBOSE_SILENT) 188 printf("%s ", filename); 189 190 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest); 191 if (fp->f_size == 0 || fp->f_addr == 0) 192 goto ioerr; 193 194 /* save exec header as metadata */ 195 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr); 196 197 /* Load OK, return module pointer */ 198 *result = (struct preloaded_file *)fp; 199 err = 0; 200 goto out; 201 202 ioerr: 203 err = EIO; 204 oerr: 205 file_discard(fp); 206 out: 207 #ifdef LOADER_VERIEXEC_VECTX 208 if (!err && ef.vctx) { 209 int verror; 210 211 verror = vectx_close(ef.vctx, VE_MUST, __func__); 212 if (verror) { 213 err = EAUTH; 214 file_discard(fp); 215 } 216 } 217 #endif 218 close(ef.fd); 219 if (ef.e_shdr != NULL) 220 free(ef.e_shdr); 221 222 return(err); 223 } 224 225 /* 226 * With the file (fd) open on the image, and (ehdr) containing 227 * the Elf header, load the image at (off) 228 */ 229 static int 230 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off) 231 { 232 Elf_Ehdr *hdr; 233 Elf_Shdr *shdr, *cshdr, *lshdr; 234 vm_offset_t firstaddr, lastaddr; 235 int i, nsym, res, ret, shdrbytes, symstrindex; 236 237 ret = 0; 238 firstaddr = lastaddr = (vm_offset_t)off; 239 hdr = &ef->hdr; 240 ef->off = (vm_offset_t)off; 241 242 /* Read in the section headers. */ 243 shdrbytes = hdr->e_shnum * hdr->e_shentsize; 244 shdr = alloc_pread(VECTX_HANDLE(ef), (off_t)hdr->e_shoff, shdrbytes); 245 if (shdr == NULL) { 246 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 247 "_obj_loadimage: read section headers failed\n"); 248 goto out; 249 } 250 ef->e_shdr = shdr; 251 252 /* 253 * Decide where to load everything, but don't read it yet. 254 * We store the load address as a non-zero sh_addr value. 255 * Start with the code/data and bss. 256 */ 257 for (i = 0; i < hdr->e_shnum; i++) 258 shdr[i].sh_addr = 0; 259 for (i = 0; i < hdr->e_shnum; i++) { 260 if (shdr[i].sh_size == 0) 261 continue; 262 switch (shdr[i].sh_type) { 263 case SHT_PROGBITS: 264 case SHT_NOBITS: 265 #if defined(__i386__) || defined(__amd64__) 266 case SHT_X86_64_UNWIND: 267 #endif 268 case SHT_INIT_ARRAY: 269 case SHT_FINI_ARRAY: 270 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 271 break; 272 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 273 shdr[i].sh_addr = (Elf_Addr)lastaddr; 274 lastaddr += shdr[i].sh_size; 275 break; 276 } 277 } 278 279 /* Symbols. */ 280 nsym = 0; 281 for (i = 0; i < hdr->e_shnum; i++) { 282 switch (shdr[i].sh_type) { 283 case SHT_SYMTAB: 284 nsym++; 285 ef->symtabindex = i; 286 break; 287 } 288 } 289 if (nsym != 1) { 290 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 291 "_obj_loadimage: file has no valid symbol table\n"); 292 goto out; 293 } 294 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign); 295 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr; 296 lastaddr += shdr[ef->symtabindex].sh_size; 297 298 symstrindex = shdr[ef->symtabindex].sh_link; 299 if (symstrindex < 0 || symstrindex >= hdr->e_shnum || 300 shdr[symstrindex].sh_type != SHT_STRTAB) { 301 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 302 "_obj_loadimage: file has invalid symbol strings\n"); 303 goto out; 304 } 305 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign); 306 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr; 307 lastaddr += shdr[symstrindex].sh_size; 308 309 /* Section names. */ 310 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum || 311 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { 312 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 313 "_obj_loadimage: file has no section names\n"); 314 goto out; 315 } 316 ef->shstrindex = hdr->e_shstrndx; 317 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign); 318 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr; 319 lastaddr += shdr[ef->shstrindex].sh_size; 320 321 /* Relocation tables. */ 322 for (i = 0; i < hdr->e_shnum; i++) { 323 switch (shdr[i].sh_type) { 324 case SHT_REL: 325 case SHT_RELA: 326 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 327 break; 328 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 329 shdr[i].sh_addr = (Elf_Addr)lastaddr; 330 lastaddr += shdr[i].sh_size; 331 break; 332 } 333 } 334 335 /* Clear the whole area, including bss regions. */ 336 kern_bzero(firstaddr, lastaddr - firstaddr); 337 338 /* Figure section with the lowest file offset we haven't loaded yet. */ 339 for (cshdr = NULL; /* none */; /* none */) 340 { 341 /* 342 * Find next section to load. The complexity of this loop is 343 * O(n^2), but with the number of sections being typically 344 * small, we do not care. 345 */ 346 lshdr = cshdr; 347 348 for (i = 0; i < hdr->e_shnum; i++) { 349 if (shdr[i].sh_addr == 0 || 350 shdr[i].sh_type == SHT_NOBITS) 351 continue; 352 /* Skip sections that were loaded already. */ 353 if (lshdr != NULL && 354 lshdr->sh_offset >= shdr[i].sh_offset) 355 continue; 356 /* Find section with smallest offset. */ 357 if (cshdr == lshdr || 358 cshdr->sh_offset > shdr[i].sh_offset) 359 cshdr = &shdr[i]; 360 } 361 362 if (cshdr == lshdr) 363 break; 364 365 if (kern_pread(VECTX_HANDLE(ef), (vm_offset_t)cshdr->sh_addr, 366 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) { 367 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 368 "_obj_loadimage: read failed\n"); 369 goto out; 370 } 371 } 372 373 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr); 374 375 res = __elfN(obj_parse_modmetadata)(fp, ef); 376 if (res != 0) 377 goto out; 378 379 ret = lastaddr - firstaddr; 380 fp->f_addr = firstaddr; 381 382 if (module_verbose > MODULE_VERBOSE_SILENT) 383 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr); 384 385 out: 386 if (module_verbose > MODULE_VERBOSE_SILENT) 387 printf("\n"); 388 return ret; 389 } 390 391 #if defined(__i386__) && __ELF_WORD_SIZE == 64 392 struct mod_metadata64 { 393 int md_version; /* structure version MDTV_* */ 394 int md_type; /* type of entry MDT_* */ 395 uint64_t md_data; /* specific data */ 396 uint64_t md_cval; /* common string label */ 397 }; 398 #endif 399 400 int 401 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef) 402 { 403 struct mod_metadata md; 404 #if defined(__i386__) && __ELF_WORD_SIZE == 64 405 struct mod_metadata64 md64; 406 #endif 407 struct mod_depend *mdepend; 408 struct mod_version mver; 409 char *s; 410 int error, modcnt, minfolen; 411 Elf_Addr v, p, p_stop; 412 413 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop, 414 &modcnt) != 0) 415 return 0; 416 417 modcnt = 0; 418 while (p < p_stop) { 419 COPYOUT(p, &v, sizeof(v)); 420 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v)); 421 if (error != 0) 422 return (error); 423 #if defined(__i386__) && __ELF_WORD_SIZE == 64 424 COPYOUT(v, &md64, sizeof(md64)); 425 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64)); 426 if (error != 0) 427 return (error); 428 md.md_version = md64.md_version; 429 md.md_type = md64.md_type; 430 md.md_cval = (const char *)(uintptr_t)md64.md_cval; 431 md.md_data = (void *)(uintptr_t)md64.md_data; 432 #else 433 COPYOUT(v, &md, sizeof(md)); 434 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md)); 435 if (error != 0) 436 return (error); 437 #endif 438 p += sizeof(Elf_Addr); 439 switch(md.md_type) { 440 case MDT_DEPEND: 441 s = strdupout((vm_offset_t)md.md_cval); 442 minfolen = sizeof(*mdepend) + strlen(s) + 1; 443 mdepend = malloc(minfolen); 444 if (mdepend == NULL) 445 return ENOMEM; 446 COPYOUT((vm_offset_t)md.md_data, mdepend, 447 sizeof(*mdepend)); 448 strcpy((char*)(mdepend + 1), s); 449 free(s); 450 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen, 451 mdepend); 452 free(mdepend); 453 break; 454 case MDT_VERSION: 455 s = strdupout((vm_offset_t)md.md_cval); 456 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver)); 457 file_addmodule(fp, s, mver.mv_version, NULL); 458 free(s); 459 modcnt++; 460 break; 461 case MDT_MODULE: 462 case MDT_PNP_INFO: 463 break; 464 default: 465 printf("unknown type %d\n", md.md_type); 466 break; 467 } 468 } 469 return 0; 470 } 471 472 static int 473 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef, 474 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp) 475 { 476 Elf_Ehdr *hdr; 477 Elf_Shdr *shdr; 478 char *p; 479 vm_offset_t shstrtab; 480 int i; 481 482 hdr = &ef->hdr; 483 shdr = ef->e_shdr; 484 shstrtab = shdr[ef->shstrindex].sh_addr; 485 486 for (i = 0; i < hdr->e_shnum; i++) { 487 if (shdr[i].sh_type != SHT_PROGBITS) 488 continue; 489 if (shdr[i].sh_name == 0) 490 continue; 491 p = strdupout(shstrtab + shdr[i].sh_name); 492 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) { 493 *startp = shdr[i].sh_addr; 494 *stopp = shdr[i].sh_addr + shdr[i].sh_size; 495 *countp = (*stopp - *startp) / sizeof(Elf_Addr); 496 free(p); 497 return (0); 498 } 499 free(p); 500 } 501 502 return (ESRCH); 503 } 504 505 /* 506 * Apply any intra-module relocations to the value. p is the load address 507 * of the value and val/len is the value to be modified. This does NOT modify 508 * the image in-place, because this is done by kern_linker later on. 509 */ 510 static int 511 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p, 512 void *val, size_t len) 513 { 514 Elf_Ehdr *hdr; 515 Elf_Shdr *shdr; 516 Elf_Addr off = p; 517 Elf_Addr base; 518 Elf_Rela a, *abase; 519 Elf_Rel r, *rbase; 520 int error, i, j, nrel, nrela; 521 522 hdr = &ef->hdr; 523 shdr = ef->e_shdr; 524 525 for (i = 0; i < hdr->e_shnum; i++) { 526 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL) 527 continue; 528 base = shdr[shdr[i].sh_info].sh_addr; 529 if (base == 0 || shdr[i].sh_addr == 0) 530 continue; 531 if (off < base || off + len > base + 532 shdr[shdr[i].sh_info].sh_size) 533 continue; 534 535 switch (shdr[i].sh_type) { 536 case SHT_RELA: 537 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr; 538 539 nrela = shdr[i].sh_size / sizeof(Elf_Rela); 540 for (j = 0; j < nrela; j++) { 541 COPYOUT(abase + j, &a, sizeof(a)); 542 543 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 544 &a, ELF_RELOC_RELA, base, off, val, len); 545 if (error != 0) 546 return (error); 547 } 548 break; 549 case SHT_REL: 550 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr; 551 552 nrel = shdr[i].sh_size / sizeof(Elf_Rel); 553 for (j = 0; j < nrel; j++) { 554 COPYOUT(rbase + j, &r, sizeof(r)); 555 556 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 557 &r, ELF_RELOC_REL, base, off, val, len); 558 if (error != 0) 559 return (error); 560 } 561 break; 562 } 563 } 564 return (0); 565 } 566 567 /* Look up the address of a specified symbol. */ 568 static Elf_Addr 569 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx) 570 { 571 Elf_Sym sym; 572 Elf_Addr base; 573 574 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym)) 575 return (0); 576 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym), 577 &sym, sizeof(sym)); 578 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum) 579 return (0); 580 base = ef->e_shdr[sym.st_shndx].sh_addr; 581 if (base == 0) 582 return (0); 583 return (base + sym.st_value); 584 } 585