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