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 printf("%s ", filename); 188 189 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest); 190 if (fp->f_size == 0 || fp->f_addr == 0) 191 goto ioerr; 192 193 /* save exec header as metadata */ 194 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr); 195 196 /* Load OK, return module pointer */ 197 *result = (struct preloaded_file *)fp; 198 err = 0; 199 goto out; 200 201 ioerr: 202 err = EIO; 203 oerr: 204 file_discard(fp); 205 out: 206 #ifdef LOADER_VERIEXEC_VECTX 207 if (!err && ef.vctx) { 208 int verror; 209 210 verror = vectx_close(ef.vctx, VE_MUST, __func__); 211 if (verror) { 212 err = EAUTH; 213 file_discard(fp); 214 } 215 } 216 #endif 217 close(ef.fd); 218 if (ef.e_shdr != NULL) 219 free(ef.e_shdr); 220 221 return(err); 222 } 223 224 /* 225 * With the file (fd) open on the image, and (ehdr) containing 226 * the Elf header, load the image at (off) 227 */ 228 static int 229 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off) 230 { 231 Elf_Ehdr *hdr; 232 Elf_Shdr *shdr, *cshdr, *lshdr; 233 vm_offset_t firstaddr, lastaddr; 234 int i, nsym, res, ret, shdrbytes, symstrindex; 235 236 ret = 0; 237 firstaddr = lastaddr = (vm_offset_t)off; 238 hdr = &ef->hdr; 239 ef->off = (vm_offset_t)off; 240 241 /* Read in the section headers. */ 242 shdrbytes = hdr->e_shnum * hdr->e_shentsize; 243 shdr = alloc_pread(VECTX_HANDLE(ef), (off_t)hdr->e_shoff, shdrbytes); 244 if (shdr == NULL) { 245 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 246 "_obj_loadimage: read section headers failed\n"); 247 goto out; 248 } 249 ef->e_shdr = shdr; 250 251 /* 252 * Decide where to load everything, but don't read it yet. 253 * We store the load address as a non-zero sh_addr value. 254 * Start with the code/data and bss. 255 */ 256 for (i = 0; i < hdr->e_shnum; i++) 257 shdr[i].sh_addr = 0; 258 for (i = 0; i < hdr->e_shnum; i++) { 259 if (shdr[i].sh_size == 0) 260 continue; 261 switch (shdr[i].sh_type) { 262 case SHT_PROGBITS: 263 case SHT_NOBITS: 264 #if defined(__i386__) || defined(__amd64__) 265 case SHT_X86_64_UNWIND: 266 #endif 267 case SHT_INIT_ARRAY: 268 case SHT_FINI_ARRAY: 269 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 270 break; 271 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 272 shdr[i].sh_addr = (Elf_Addr)lastaddr; 273 lastaddr += shdr[i].sh_size; 274 break; 275 } 276 } 277 278 /* Symbols. */ 279 nsym = 0; 280 for (i = 0; i < hdr->e_shnum; i++) { 281 switch (shdr[i].sh_type) { 282 case SHT_SYMTAB: 283 nsym++; 284 ef->symtabindex = i; 285 shdr[i].sh_addr = (Elf_Addr)lastaddr; 286 lastaddr += shdr[i].sh_size; 287 break; 288 } 289 } 290 if (nsym != 1) { 291 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 292 "_obj_loadimage: file has no valid symbol table\n"); 293 goto out; 294 } 295 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign); 296 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr; 297 lastaddr += shdr[ef->symtabindex].sh_size; 298 299 symstrindex = shdr[ef->symtabindex].sh_link; 300 if (symstrindex < 0 || symstrindex >= hdr->e_shnum || 301 shdr[symstrindex].sh_type != SHT_STRTAB) { 302 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 303 "_obj_loadimage: file has invalid symbol strings\n"); 304 goto out; 305 } 306 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign); 307 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr; 308 lastaddr += shdr[symstrindex].sh_size; 309 310 /* Section names. */ 311 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum || 312 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { 313 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 314 "_obj_loadimage: file has no section names\n"); 315 goto out; 316 } 317 ef->shstrindex = hdr->e_shstrndx; 318 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign); 319 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr; 320 lastaddr += shdr[ef->shstrindex].sh_size; 321 322 /* Relocation tables. */ 323 for (i = 0; i < hdr->e_shnum; i++) { 324 switch (shdr[i].sh_type) { 325 case SHT_REL: 326 case SHT_RELA: 327 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 328 break; 329 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 330 shdr[i].sh_addr = (Elf_Addr)lastaddr; 331 lastaddr += shdr[i].sh_size; 332 break; 333 } 334 } 335 336 /* Clear the whole area, including bss regions. */ 337 kern_bzero(firstaddr, lastaddr - firstaddr); 338 339 /* Figure section with the lowest file offset we haven't loaded yet. */ 340 for (cshdr = NULL; /* none */; /* none */) 341 { 342 /* 343 * Find next section to load. The complexity of this loop is 344 * O(n^2), but with the number of sections being typically 345 * small, we do not care. 346 */ 347 lshdr = cshdr; 348 349 for (i = 0; i < hdr->e_shnum; i++) { 350 if (shdr[i].sh_addr == 0 || 351 shdr[i].sh_type == SHT_NOBITS) 352 continue; 353 /* Skip sections that were loaded already. */ 354 if (lshdr != NULL && 355 lshdr->sh_offset >= shdr[i].sh_offset) 356 continue; 357 /* Find section with smallest offset. */ 358 if (cshdr == lshdr || 359 cshdr->sh_offset > shdr[i].sh_offset) 360 cshdr = &shdr[i]; 361 } 362 363 if (cshdr == lshdr) 364 break; 365 366 if (kern_pread(VECTX_HANDLE(ef), (vm_offset_t)cshdr->sh_addr, 367 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) { 368 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 369 "_obj_loadimage: read failed\n"); 370 goto out; 371 } 372 } 373 374 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr); 375 376 res = __elfN(obj_parse_modmetadata)(fp, ef); 377 if (res != 0) 378 goto out; 379 380 ret = lastaddr - firstaddr; 381 fp->f_addr = firstaddr; 382 383 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr); 384 385 out: 386 printf("\n"); 387 return ret; 388 } 389 390 #if defined(__i386__) && __ELF_WORD_SIZE == 64 391 struct mod_metadata64 { 392 int md_version; /* structure version MDTV_* */ 393 int md_type; /* type of entry MDT_* */ 394 uint64_t md_data; /* specific data */ 395 uint64_t md_cval; /* common string label */ 396 }; 397 #endif 398 399 int 400 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef) 401 { 402 struct mod_metadata md; 403 #if defined(__i386__) && __ELF_WORD_SIZE == 64 404 struct mod_metadata64 md64; 405 #endif 406 struct mod_depend *mdepend; 407 struct mod_version mver; 408 char *s; 409 int error, modcnt, minfolen; 410 Elf_Addr v, p, p_stop; 411 412 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop, 413 &modcnt) != 0) 414 return 0; 415 416 modcnt = 0; 417 while (p < p_stop) { 418 COPYOUT(p, &v, sizeof(v)); 419 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v)); 420 if (error != 0) 421 return (error); 422 #if defined(__i386__) && __ELF_WORD_SIZE == 64 423 COPYOUT(v, &md64, sizeof(md64)); 424 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64)); 425 if (error != 0) 426 return (error); 427 md.md_version = md64.md_version; 428 md.md_type = md64.md_type; 429 md.md_cval = (const char *)(uintptr_t)md64.md_cval; 430 md.md_data = (void *)(uintptr_t)md64.md_data; 431 #else 432 COPYOUT(v, &md, sizeof(md)); 433 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md)); 434 if (error != 0) 435 return (error); 436 #endif 437 p += sizeof(Elf_Addr); 438 switch(md.md_type) { 439 case MDT_DEPEND: 440 s = strdupout((vm_offset_t)md.md_cval); 441 minfolen = sizeof(*mdepend) + strlen(s) + 1; 442 mdepend = malloc(minfolen); 443 if (mdepend == NULL) 444 return ENOMEM; 445 COPYOUT((vm_offset_t)md.md_data, mdepend, 446 sizeof(*mdepend)); 447 strcpy((char*)(mdepend + 1), s); 448 free(s); 449 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen, 450 mdepend); 451 free(mdepend); 452 break; 453 case MDT_VERSION: 454 s = strdupout((vm_offset_t)md.md_cval); 455 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver)); 456 file_addmodule(fp, s, mver.mv_version, NULL); 457 free(s); 458 modcnt++; 459 break; 460 case MDT_MODULE: 461 case MDT_PNP_INFO: 462 break; 463 default: 464 printf("unknown type %d\n", md.md_type); 465 break; 466 } 467 } 468 return 0; 469 } 470 471 static int 472 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef, 473 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp) 474 { 475 Elf_Ehdr *hdr; 476 Elf_Shdr *shdr; 477 char *p; 478 vm_offset_t shstrtab; 479 int i; 480 481 hdr = &ef->hdr; 482 shdr = ef->e_shdr; 483 shstrtab = shdr[ef->shstrindex].sh_addr; 484 485 for (i = 0; i < hdr->e_shnum; i++) { 486 if (shdr[i].sh_type != SHT_PROGBITS) 487 continue; 488 if (shdr[i].sh_name == 0) 489 continue; 490 p = strdupout(shstrtab + shdr[i].sh_name); 491 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) { 492 *startp = shdr[i].sh_addr; 493 *stopp = shdr[i].sh_addr + shdr[i].sh_size; 494 *countp = (*stopp - *startp) / sizeof(Elf_Addr); 495 free(p); 496 return (0); 497 } 498 free(p); 499 } 500 501 return (ESRCH); 502 } 503 504 /* 505 * Apply any intra-module relocations to the value. p is the load address 506 * of the value and val/len is the value to be modified. This does NOT modify 507 * the image in-place, because this is done by kern_linker later on. 508 */ 509 static int 510 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p, 511 void *val, size_t len) 512 { 513 Elf_Ehdr *hdr; 514 Elf_Shdr *shdr; 515 Elf_Addr off = p; 516 Elf_Addr base; 517 Elf_Rela a, *abase; 518 Elf_Rel r, *rbase; 519 int error, i, j, nrel, nrela; 520 521 hdr = &ef->hdr; 522 shdr = ef->e_shdr; 523 524 for (i = 0; i < hdr->e_shnum; i++) { 525 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL) 526 continue; 527 base = shdr[shdr[i].sh_info].sh_addr; 528 if (base == 0 || shdr[i].sh_addr == 0) 529 continue; 530 if (off < base || off + len > base + 531 shdr[shdr[i].sh_info].sh_size) 532 continue; 533 534 switch (shdr[i].sh_type) { 535 case SHT_RELA: 536 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr; 537 538 nrela = shdr[i].sh_size / sizeof(Elf_Rela); 539 for (j = 0; j < nrela; j++) { 540 COPYOUT(abase + j, &a, sizeof(a)); 541 542 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 543 &a, ELF_RELOC_RELA, base, off, val, len); 544 if (error != 0) 545 return (error); 546 } 547 break; 548 case SHT_REL: 549 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr; 550 551 nrel = shdr[i].sh_size / sizeof(Elf_Rel); 552 for (j = 0; j < nrel; j++) { 553 COPYOUT(rbase + j, &r, sizeof(r)); 554 555 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 556 &r, ELF_RELOC_REL, base, off, val, len); 557 if (error != 0) 558 return (error); 559 } 560 break; 561 } 562 } 563 return (0); 564 } 565 566 /* Look up the address of a specified symbol. */ 567 static Elf_Addr 568 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx) 569 { 570 Elf_Sym sym; 571 Elf_Addr base; 572 573 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym)) 574 return (0); 575 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym), 576 &sym, sizeof(sym)); 577 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum) 578 return (0); 579 base = ef->e_shdr[sym.st_shndx].sh_addr; 580 if (base == 0) 581 return (0); 582 return (base + sym.st_value); 583 } 584