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