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 <inttypes.h> 37 #include <string.h> 38 #include <machine/elf.h> 39 #include <stand.h> 40 #define FREEBSD_ELF 41 #include <link.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 u_int64_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, u_int64_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 kfp = file_findfile(NULL, __elfN(obj_kerneltype)); 133 if (kfp == NULL) { 134 printf("elf" __XSTRING(__ELF_WORD_SIZE) 135 "_obj_loadfile: can't load module before kernel\n"); 136 err = EPERM; 137 goto oerr; 138 } 139 140 if (archsw.arch_loadaddr != NULL) 141 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest); 142 else 143 dest = roundup(dest, PAGE_SIZE); 144 145 /* 146 * Ok, we think we should handle this. 147 */ 148 fp = file_alloc(); 149 if (fp == NULL) { 150 printf("elf" __XSTRING(__ELF_WORD_SIZE) 151 "_obj_loadfile: cannot allocate module info\n"); 152 err = EPERM; 153 goto out; 154 } 155 fp->f_name = strdup(filename); 156 fp->f_type = strdup(__elfN(obj_moduletype)); 157 158 printf("%s ", filename); 159 160 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest); 161 if (fp->f_size == 0 || fp->f_addr == 0) 162 goto ioerr; 163 164 /* save exec header as metadata */ 165 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr); 166 167 /* Load OK, return module pointer */ 168 *result = (struct preloaded_file *)fp; 169 err = 0; 170 goto out; 171 172 ioerr: 173 err = EIO; 174 oerr: 175 file_discard(fp); 176 out: 177 close(ef.fd); 178 if (ef.e_shdr != NULL) 179 free(ef.e_shdr); 180 181 return(err); 182 } 183 184 /* 185 * With the file (fd) open on the image, and (ehdr) containing 186 * the Elf header, load the image at (off) 187 */ 188 static int 189 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off) 190 { 191 Elf_Ehdr *hdr; 192 Elf_Shdr *shdr, *cshdr, *lshdr; 193 vm_offset_t firstaddr, lastaddr; 194 int i, nsym, res, ret, shdrbytes, symstrindex; 195 196 ret = 0; 197 firstaddr = lastaddr = (vm_offset_t)off; 198 hdr = &ef->hdr; 199 ef->off = (vm_offset_t)off; 200 201 /* Read in the section headers. */ 202 shdrbytes = hdr->e_shnum * hdr->e_shentsize; 203 shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes); 204 if (shdr == NULL) { 205 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 206 "_obj_loadimage: read section headers failed\n"); 207 goto out; 208 } 209 ef->e_shdr = shdr; 210 211 /* 212 * Decide where to load everything, but don't read it yet. 213 * We store the load address as a non-zero sh_addr value. 214 * Start with the code/data and bss. 215 */ 216 for (i = 0; i < hdr->e_shnum; i++) 217 shdr[i].sh_addr = 0; 218 for (i = 0; i < hdr->e_shnum; i++) { 219 if (shdr[i].sh_size == 0) 220 continue; 221 switch (shdr[i].sh_type) { 222 case SHT_PROGBITS: 223 case SHT_NOBITS: 224 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 225 shdr[i].sh_addr = (Elf_Addr)lastaddr; 226 lastaddr += shdr[i].sh_size; 227 break; 228 } 229 } 230 231 /* Symbols. */ 232 nsym = 0; 233 for (i = 0; i < hdr->e_shnum; i++) { 234 switch (shdr[i].sh_type) { 235 case SHT_SYMTAB: 236 nsym++; 237 ef->symtabindex = i; 238 shdr[i].sh_addr = (Elf_Addr)lastaddr; 239 lastaddr += shdr[i].sh_size; 240 break; 241 } 242 } 243 if (nsym != 1) { 244 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 245 "_obj_loadimage: file has no valid symbol table\n"); 246 goto out; 247 } 248 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign); 249 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr; 250 lastaddr += shdr[ef->symtabindex].sh_size; 251 252 symstrindex = shdr[ef->symtabindex].sh_link; 253 if (symstrindex < 0 || symstrindex >= hdr->e_shnum || 254 shdr[symstrindex].sh_type != SHT_STRTAB) { 255 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 256 "_obj_loadimage: file has invalid symbol strings\n"); 257 goto out; 258 } 259 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign); 260 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr; 261 lastaddr += shdr[symstrindex].sh_size; 262 263 /* Section names. */ 264 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum || 265 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { 266 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 267 "_obj_loadimage: file has no section names\n"); 268 goto out; 269 } 270 ef->shstrindex = hdr->e_shstrndx; 271 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign); 272 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr; 273 lastaddr += shdr[ef->shstrindex].sh_size; 274 275 /* Relocation tables. */ 276 for (i = 0; i < hdr->e_shnum; i++) { 277 switch (shdr[i].sh_type) { 278 case SHT_REL: 279 case SHT_RELA: 280 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 281 shdr[i].sh_addr = (Elf_Addr)lastaddr; 282 lastaddr += shdr[i].sh_size; 283 break; 284 } 285 } 286 287 /* Clear the whole area, including bss regions. */ 288 kern_bzero(firstaddr, lastaddr - firstaddr); 289 290 /* Figure section with the lowest file offset we haven't loaded yet. */ 291 for (cshdr = NULL; /* none */; /* none */) 292 { 293 /* 294 * Find next section to load. The complexity of this loop is 295 * O(n^2), but with the number of sections being typically 296 * small, we do not care. 297 */ 298 lshdr = cshdr; 299 300 for (i = 0; i < hdr->e_shnum; i++) { 301 if (shdr[i].sh_addr == 0 || 302 shdr[i].sh_type == SHT_NOBITS) 303 continue; 304 /* Skip sections that were loaded already. */ 305 if (lshdr != NULL && 306 lshdr->sh_offset >= shdr[i].sh_offset) 307 continue; 308 /* Find section with smallest offset. */ 309 if (cshdr == lshdr || 310 cshdr->sh_offset > shdr[i].sh_offset) 311 cshdr = &shdr[i]; 312 } 313 314 if (cshdr == lshdr) 315 break; 316 317 if (kern_pread(ef->fd, (vm_offset_t)cshdr->sh_addr, 318 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) { 319 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 320 "_obj_loadimage: read failed\n"); 321 goto out; 322 } 323 } 324 325 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr); 326 327 res = __elfN(obj_parse_modmetadata)(fp, ef); 328 if (res != 0) 329 goto out; 330 331 ret = lastaddr - firstaddr; 332 fp->f_addr = firstaddr; 333 334 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr); 335 336 out: 337 printf("\n"); 338 return ret; 339 } 340 341 #if defined(__i386__) && __ELF_WORD_SIZE == 64 342 struct mod_metadata64 { 343 int md_version; /* structure version MDTV_* */ 344 int md_type; /* type of entry MDT_* */ 345 u_int64_t md_data; /* specific data */ 346 u_int64_t md_cval; /* common string label */ 347 }; 348 #endif 349 350 int 351 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef) 352 { 353 struct mod_metadata md; 354 #if defined(__i386__) && __ELF_WORD_SIZE == 64 355 struct mod_metadata64 md64; 356 #endif 357 struct mod_depend *mdepend; 358 struct mod_version mver; 359 char *s; 360 int error, modcnt, minfolen; 361 Elf_Addr v, p, p_stop; 362 363 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop, 364 &modcnt) != 0) 365 return 0; 366 367 modcnt = 0; 368 while (p < p_stop) { 369 COPYOUT(p, &v, sizeof(v)); 370 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v)); 371 if (error != 0) 372 return (error); 373 #if defined(__i386__) && __ELF_WORD_SIZE == 64 374 COPYOUT(v, &md64, sizeof(md64)); 375 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64)); 376 if (error != 0) 377 return (error); 378 md.md_version = md64.md_version; 379 md.md_type = md64.md_type; 380 md.md_cval = (const char *)(uintptr_t)md64.md_cval; 381 md.md_data = (void *)(uintptr_t)md64.md_data; 382 #else 383 COPYOUT(v, &md, sizeof(md)); 384 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md)); 385 if (error != 0) 386 return (error); 387 #endif 388 p += sizeof(Elf_Addr); 389 switch(md.md_type) { 390 case MDT_DEPEND: 391 s = strdupout((vm_offset_t)md.md_cval); 392 minfolen = sizeof(*mdepend) + strlen(s) + 1; 393 mdepend = malloc(minfolen); 394 if (mdepend == NULL) 395 return ENOMEM; 396 COPYOUT((vm_offset_t)md.md_data, mdepend, 397 sizeof(*mdepend)); 398 strcpy((char*)(mdepend + 1), s); 399 free(s); 400 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen, 401 mdepend); 402 free(mdepend); 403 break; 404 case MDT_VERSION: 405 s = strdupout((vm_offset_t)md.md_cval); 406 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver)); 407 file_addmodule(fp, s, mver.mv_version, NULL); 408 free(s); 409 modcnt++; 410 break; 411 case MDT_MODULE: 412 case MDT_PNP_INFO: 413 break; 414 default: 415 printf("unknown type %d\n", md.md_type); 416 break; 417 } 418 } 419 return 0; 420 } 421 422 static int 423 __elfN(obj_lookup_set)(struct preloaded_file *fp __unused, elf_file_t ef, 424 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp) 425 { 426 Elf_Ehdr *hdr; 427 Elf_Shdr *shdr; 428 char *p; 429 vm_offset_t shstrtab; 430 int i; 431 432 hdr = &ef->hdr; 433 shdr = ef->e_shdr; 434 shstrtab = shdr[ef->shstrindex].sh_addr; 435 436 for (i = 0; i < hdr->e_shnum; i++) { 437 if (shdr[i].sh_type != SHT_PROGBITS) 438 continue; 439 if (shdr[i].sh_name == 0) 440 continue; 441 p = strdupout(shstrtab + shdr[i].sh_name); 442 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) { 443 *startp = shdr[i].sh_addr; 444 *stopp = shdr[i].sh_addr + shdr[i].sh_size; 445 *countp = (*stopp - *startp) / sizeof(Elf_Addr); 446 free(p); 447 return (0); 448 } 449 free(p); 450 } 451 452 return (ESRCH); 453 } 454 455 /* 456 * Apply any intra-module relocations to the value. p is the load address 457 * of the value and val/len is the value to be modified. This does NOT modify 458 * the image in-place, because this is done by kern_linker later on. 459 */ 460 static int 461 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p, 462 void *val, size_t len) 463 { 464 Elf_Ehdr *hdr; 465 Elf_Shdr *shdr; 466 Elf_Addr off = p; 467 Elf_Addr base; 468 Elf_Rela a, *abase; 469 Elf_Rel r, *rbase; 470 int error, i, j, nrel, nrela; 471 472 (void)mp; 473 hdr = &ef->hdr; 474 shdr = ef->e_shdr; 475 476 for (i = 0; i < hdr->e_shnum; i++) { 477 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL) 478 continue; 479 base = shdr[shdr[i].sh_info].sh_addr; 480 if (base == 0 || shdr[i].sh_addr == 0) 481 continue; 482 if (off < base || off + len > base + 483 shdr[shdr[i].sh_info].sh_size) 484 continue; 485 486 switch (shdr[i].sh_type) { 487 case SHT_RELA: 488 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr; 489 490 nrela = shdr[i].sh_size / sizeof(Elf_Rela); 491 for (j = 0; j < nrela; j++) { 492 COPYOUT(abase + j, &a, sizeof(a)); 493 494 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 495 &a, ELF_RELOC_RELA, base, off, val, len); 496 if (error != 0) 497 return (error); 498 } 499 break; 500 case SHT_REL: 501 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr; 502 503 nrel = shdr[i].sh_size / sizeof(Elf_Rel); 504 for (j = 0; j < nrel; j++) { 505 COPYOUT(rbase + j, &r, sizeof(r)); 506 507 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 508 &r, ELF_RELOC_REL, base, off, val, len); 509 if (error != 0) 510 return (error); 511 } 512 break; 513 } 514 } 515 return (0); 516 } 517 518 /* Look up the address of a specified symbol. */ 519 static Elf_Addr 520 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx) 521 { 522 Elf_Sym sym; 523 Elf_Addr base; 524 525 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym)) 526 return (0); 527 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym), 528 &sym, sizeof(sym)); 529 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum) 530 return (0); 531 base = ef->e_shdr[sym.st_shndx].sh_addr; 532 if (base == 0) 533 return (0); 534 return (base + sym.st_value); 535 } 536