1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1998-2000 Doug Rabson 5 * Copyright (c) 2004 Peter Wemm 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include "opt_ddb.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/fcntl.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/malloc.h> 41 #include <sys/linker.h> 42 #include <sys/mutex.h> 43 #include <sys/mount.h> 44 #include <sys/namei.h> 45 #include <sys/proc.h> 46 #include <sys/rwlock.h> 47 #include <sys/vnode.h> 48 49 #include <machine/elf.h> 50 51 #include <net/vnet.h> 52 53 #include <security/mac/mac_framework.h> 54 55 #include <vm/vm.h> 56 #include <vm/vm_param.h> 57 #include <vm/pmap.h> 58 #include <vm/vm_extern.h> 59 #include <vm/vm_kern.h> 60 #include <vm/vm_map.h> 61 #include <vm/vm_object.h> 62 #include <vm/vm_page.h> 63 #include <vm/vm_pager.h> 64 65 #include <sys/link_elf.h> 66 67 #ifdef DDB_CTF 68 #include <contrib/zlib/zlib.h> 69 #endif 70 71 #include "linker_if.h" 72 73 typedef struct { 74 void *addr; 75 Elf_Off size; 76 int flags; /* Section flags. */ 77 int sec; /* Original section number. */ 78 char *name; 79 } Elf_progent; 80 81 typedef struct { 82 Elf_Rel *rel; 83 int nrel; 84 int sec; 85 } Elf_relent; 86 87 typedef struct { 88 Elf_Rela *rela; 89 int nrela; 90 int sec; 91 } Elf_relaent; 92 93 typedef struct elf_file { 94 struct linker_file lf; /* Common fields */ 95 96 int preloaded; 97 caddr_t address; /* Relocation address */ 98 vm_object_t object; /* VM object to hold file pages */ 99 Elf_Shdr *e_shdr; 100 101 Elf_progent *progtab; 102 u_int nprogtab; 103 104 Elf_relaent *relatab; 105 u_int nrelatab; 106 107 Elf_relent *reltab; 108 int nreltab; 109 110 Elf_Sym *ddbsymtab; /* The symbol table we are using */ 111 long ddbsymcnt; /* Number of symbols */ 112 caddr_t ddbstrtab; /* String table */ 113 long ddbstrcnt; /* number of bytes in string table */ 114 115 caddr_t shstrtab; /* Section name string table */ 116 long shstrcnt; /* number of bytes in string table */ 117 118 caddr_t ctftab; /* CTF table */ 119 long ctfcnt; /* number of bytes in CTF table */ 120 caddr_t ctfoff; /* CTF offset table */ 121 caddr_t typoff; /* Type offset table */ 122 long typlen; /* Number of type entries. */ 123 124 } *elf_file_t; 125 126 #include <kern/kern_ctf.c> 127 128 static int link_elf_link_preload(linker_class_t cls, 129 const char *, linker_file_t *); 130 static int link_elf_link_preload_finish(linker_file_t); 131 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 132 static int link_elf_lookup_symbol(linker_file_t, const char *, 133 c_linker_sym_t *); 134 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 135 linker_symval_t *); 136 static int link_elf_search_symbol(linker_file_t, caddr_t value, 137 c_linker_sym_t *sym, long *diffp); 138 139 static void link_elf_unload_file(linker_file_t); 140 static int link_elf_lookup_set(linker_file_t, const char *, 141 void ***, void ***, int *); 142 static int link_elf_each_function_name(linker_file_t, 143 int (*)(const char *, void *), void *); 144 static int link_elf_each_function_nameval(linker_file_t, 145 linker_function_nameval_callback_t, 146 void *); 147 static int link_elf_reloc_local(linker_file_t, bool); 148 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 149 static long link_elf_strtab_get(linker_file_t, caddr_t *); 150 151 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, 152 Elf_Addr *); 153 154 static kobj_method_t link_elf_methods[] = { 155 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 156 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 157 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 158 KOBJMETHOD(linker_unload, link_elf_unload_file), 159 KOBJMETHOD(linker_load_file, link_elf_load_file), 160 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 161 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 162 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 163 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 164 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 165 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 166 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 167 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 168 KOBJMETHOD_END 169 }; 170 171 static struct linker_class link_elf_class = { 172 #if ELF_TARG_CLASS == ELFCLASS32 173 "elf32_obj", 174 #else 175 "elf64_obj", 176 #endif 177 link_elf_methods, sizeof(struct elf_file) 178 }; 179 180 static int relocate_file(elf_file_t ef); 181 static void elf_obj_cleanup_globals_cache(elf_file_t); 182 183 static void 184 link_elf_error(const char *filename, const char *s) 185 { 186 if (filename == NULL) 187 printf("kldload: %s\n", s); 188 else 189 printf("kldload: %s: %s\n", filename, s); 190 } 191 192 static void 193 link_elf_init(void *arg) 194 { 195 196 linker_add_class(&link_elf_class); 197 } 198 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL); 199 200 static void 201 link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end, 202 vm_prot_t prot) 203 { 204 int error __unused; 205 206 KASSERT(start <= end && start >= (vm_offset_t)ef->address && 207 end <= round_page((vm_offset_t)ef->address + ef->lf.size), 208 ("link_elf_protect_range: invalid range %#jx-%#jx", 209 (uintmax_t)start, (uintmax_t)end)); 210 211 if (start == end) 212 return; 213 if (ef->preloaded) { 214 #ifdef __amd64__ 215 error = pmap_change_prot(start, end - start, prot); 216 KASSERT(error == 0, 217 ("link_elf_protect_range: pmap_change_prot() returned %d", 218 error)); 219 #endif 220 return; 221 } 222 error = vm_map_protect(kernel_map, start, end, prot, 0, 223 VM_MAP_PROTECT_SET_PROT); 224 KASSERT(error == KERN_SUCCESS, 225 ("link_elf_protect_range: vm_map_protect() returned %d", error)); 226 } 227 228 /* 229 * Restrict permissions on linker file memory based on section flags. 230 * Sections need not be page-aligned, so overlap within a page is possible. 231 */ 232 static void 233 link_elf_protect(elf_file_t ef) 234 { 235 vm_offset_t end, segend, segstart, start; 236 vm_prot_t gapprot, prot, segprot; 237 int i; 238 239 /* 240 * If the file was preloaded, the last page may contain other preloaded 241 * data which may need to be writeable. ELF files are always 242 * page-aligned, but other preloaded data, such as entropy or CPU 243 * microcode may be loaded with a smaller alignment. 244 */ 245 gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ; 246 247 start = end = (vm_offset_t)ef->address; 248 prot = VM_PROT_READ; 249 for (i = 0; i < ef->nprogtab; i++) { 250 /* 251 * VNET and DPCPU sections have their memory allocated by their 252 * respective subsystems. 253 */ 254 if (ef->progtab[i].name != NULL && ( 255 #ifdef VIMAGE 256 strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 || 257 #endif 258 strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0)) 259 continue; 260 261 segstart = trunc_page((vm_offset_t)ef->progtab[i].addr); 262 segend = round_page((vm_offset_t)ef->progtab[i].addr + 263 ef->progtab[i].size); 264 segprot = VM_PROT_READ; 265 if ((ef->progtab[i].flags & SHF_WRITE) != 0) 266 segprot |= VM_PROT_WRITE; 267 if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0) 268 segprot |= VM_PROT_EXECUTE; 269 270 if (end <= segstart) { 271 /* 272 * Case 1: there is no overlap between the previous 273 * segment and this one. Apply protections to the 274 * previous segment, and protect the gap between the 275 * previous and current segments, if any. 276 */ 277 link_elf_protect_range(ef, start, end, prot); 278 link_elf_protect_range(ef, end, segstart, gapprot); 279 280 start = segstart; 281 end = segend; 282 prot = segprot; 283 } else if (start < segstart && end == segend) { 284 /* 285 * Case 2: the current segment is a subrange of the 286 * previous segment. Apply protections to the 287 * non-overlapping portion of the previous segment. 288 */ 289 link_elf_protect_range(ef, start, segstart, prot); 290 291 start = segstart; 292 prot |= segprot; 293 } else if (end < segend) { 294 /* 295 * Case 3: there is partial overlap between the previous 296 * and current segments. Apply protections to the 297 * non-overlapping portion of the previous segment, and 298 * then the overlap, which must use the union of the two 299 * segments' protections. 300 */ 301 link_elf_protect_range(ef, start, segstart, prot); 302 link_elf_protect_range(ef, segstart, end, 303 prot | segprot); 304 start = end; 305 end = segend; 306 prot = segprot; 307 } else { 308 /* 309 * Case 4: the two segments reside in the same page. 310 */ 311 prot |= segprot; 312 } 313 } 314 315 /* 316 * Fix up the last unprotected segment and trailing data. 317 */ 318 link_elf_protect_range(ef, start, end, prot); 319 link_elf_protect_range(ef, end, 320 round_page((vm_offset_t)ef->address + ef->lf.size), gapprot); 321 } 322 323 static int 324 link_elf_link_preload(linker_class_t cls, const char *filename, 325 linker_file_t *result) 326 { 327 Elf_Ehdr *hdr; 328 Elf_Shdr *shdr; 329 Elf_Sym *es; 330 void *modptr, *baseptr, *sizeptr; 331 char *type; 332 elf_file_t ef; 333 linker_file_t lf; 334 Elf_Addr off; 335 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex; 336 337 /* Look to see if we have the file preloaded */ 338 modptr = preload_search_by_name(filename); 339 if (modptr == NULL) 340 return ENOENT; 341 342 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 343 baseptr = preload_search_info(modptr, MODINFO_ADDR); 344 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 345 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA | 346 MODINFOMD_ELFHDR); 347 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA | 348 MODINFOMD_SHDR); 349 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) 350 " obj module") != 0 && 351 strcmp(type, "elf obj module") != 0)) { 352 return (EFTYPE); 353 } 354 if (baseptr == NULL || sizeptr == NULL || hdr == NULL || 355 shdr == NULL) 356 return (EINVAL); 357 358 lf = linker_make_file(filename, &link_elf_class); 359 if (lf == NULL) 360 return (ENOMEM); 361 362 ef = (elf_file_t)lf; 363 ef->preloaded = 1; 364 ef->address = *(caddr_t *)baseptr; 365 lf->address = *(caddr_t *)baseptr; 366 lf->size = *(size_t *)sizeptr; 367 368 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 369 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 370 hdr->e_ident[EI_VERSION] != EV_CURRENT || 371 hdr->e_version != EV_CURRENT || 372 hdr->e_type != ET_REL || 373 hdr->e_machine != ELF_TARG_MACH) { 374 error = EFTYPE; 375 goto out; 376 } 377 ef->e_shdr = shdr; 378 379 /* Scan the section header for information and table sizing. */ 380 symtabindex = -1; 381 symstrindex = -1; 382 for (i = 0; i < hdr->e_shnum; i++) { 383 switch (shdr[i].sh_type) { 384 case SHT_PROGBITS: 385 case SHT_NOBITS: 386 #ifdef __amd64__ 387 case SHT_X86_64_UNWIND: 388 #endif 389 case SHT_INIT_ARRAY: 390 case SHT_FINI_ARRAY: 391 /* Ignore sections not loaded by the loader. */ 392 if (shdr[i].sh_addr == 0) 393 break; 394 ef->nprogtab++; 395 break; 396 case SHT_SYMTAB: 397 symtabindex = i; 398 symstrindex = shdr[i].sh_link; 399 break; 400 case SHT_REL: 401 /* 402 * Ignore relocation tables for sections not 403 * loaded by the loader. 404 */ 405 if (shdr[shdr[i].sh_info].sh_addr == 0) 406 break; 407 ef->nreltab++; 408 break; 409 case SHT_RELA: 410 if (shdr[shdr[i].sh_info].sh_addr == 0) 411 break; 412 ef->nrelatab++; 413 break; 414 } 415 } 416 417 shstrindex = hdr->e_shstrndx; 418 if (ef->nprogtab == 0 || symstrindex < 0 || 419 symstrindex >= hdr->e_shnum || 420 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 || 421 shstrindex >= hdr->e_shnum || 422 shdr[shstrindex].sh_type != SHT_STRTAB) { 423 printf("%s: bad/missing section headers\n", filename); 424 error = ENOEXEC; 425 goto out; 426 } 427 428 /* Allocate space for tracking the load chunks */ 429 if (ef->nprogtab != 0) 430 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 431 M_LINKER, M_WAITOK | M_ZERO); 432 if (ef->nreltab != 0) 433 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 434 M_LINKER, M_WAITOK | M_ZERO); 435 if (ef->nrelatab != 0) 436 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 437 M_LINKER, M_WAITOK | M_ZERO); 438 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 439 (ef->nreltab != 0 && ef->reltab == NULL) || 440 (ef->nrelatab != 0 && ef->relatab == NULL)) { 441 error = ENOMEM; 442 goto out; 443 } 444 445 /* XXX, relocate the sh_addr fields saved by the loader. */ 446 off = 0; 447 for (i = 0; i < hdr->e_shnum; i++) { 448 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off)) 449 off = shdr[i].sh_addr; 450 } 451 for (i = 0; i < hdr->e_shnum; i++) { 452 if (shdr[i].sh_addr != 0) 453 shdr[i].sh_addr = shdr[i].sh_addr - off + 454 (Elf_Addr)ef->address; 455 } 456 457 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 458 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr; 459 ef->ddbstrcnt = shdr[symstrindex].sh_size; 460 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr; 461 ef->shstrcnt = shdr[shstrindex].sh_size; 462 ef->shstrtab = (char *)shdr[shstrindex].sh_addr; 463 464 /* Now fill out progtab and the relocation tables. */ 465 pb = 0; 466 rl = 0; 467 ra = 0; 468 for (i = 0; i < hdr->e_shnum; i++) { 469 switch (shdr[i].sh_type) { 470 case SHT_PROGBITS: 471 case SHT_NOBITS: 472 #ifdef __amd64__ 473 case SHT_X86_64_UNWIND: 474 #endif 475 case SHT_FINI_ARRAY: 476 if (shdr[i].sh_addr == 0) 477 break; 478 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 479 if (shdr[i].sh_type == SHT_PROGBITS) 480 ef->progtab[pb].name = "<<PROGBITS>>"; 481 #ifdef __amd64__ 482 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 483 ef->progtab[pb].name = "<<UNWIND>>"; 484 #endif 485 else if (shdr[i].sh_type == SHT_INIT_ARRAY) 486 ef->progtab[pb].name = "<<INIT_ARRAY>>"; 487 else if (shdr[i].sh_type == SHT_FINI_ARRAY) 488 ef->progtab[pb].name = "<<FINI_ARRAY>>"; 489 else 490 ef->progtab[pb].name = "<<NOBITS>>"; 491 ef->progtab[pb].size = shdr[i].sh_size; 492 ef->progtab[pb].flags = shdr[i].sh_flags; 493 ef->progtab[pb].sec = i; 494 if (ef->shstrtab && shdr[i].sh_name != 0) 495 ef->progtab[pb].name = 496 ef->shstrtab + shdr[i].sh_name; 497 if (ef->progtab[pb].name != NULL && 498 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 499 void *dpcpu; 500 501 dpcpu = dpcpu_alloc(shdr[i].sh_size); 502 if (dpcpu == NULL) { 503 printf("%s: pcpu module space is out " 504 "of space; cannot allocate %#jx " 505 "for %s\n", __func__, 506 (uintmax_t)shdr[i].sh_size, 507 filename); 508 error = ENOSPC; 509 goto out; 510 } 511 memcpy(dpcpu, ef->progtab[pb].addr, 512 ef->progtab[pb].size); 513 dpcpu_copy(dpcpu, shdr[i].sh_size); 514 ef->progtab[pb].addr = dpcpu; 515 #ifdef VIMAGE 516 } else if (ef->progtab[pb].name != NULL && 517 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 518 void *vnet_data; 519 520 vnet_data = vnet_data_alloc(shdr[i].sh_size); 521 if (vnet_data == NULL) { 522 printf("%s: vnet module space is out " 523 "of space; cannot allocate %#jx " 524 "for %s\n", __func__, 525 (uintmax_t)shdr[i].sh_size, 526 filename); 527 error = ENOSPC; 528 goto out; 529 } 530 memcpy(vnet_data, ef->progtab[pb].addr, 531 ef->progtab[pb].size); 532 vnet_data_copy(vnet_data, shdr[i].sh_size); 533 ef->progtab[pb].addr = vnet_data; 534 #endif 535 } else if ((ef->progtab[pb].name != NULL && 536 strcmp(ef->progtab[pb].name, ".ctors") == 0) || 537 shdr[i].sh_type == SHT_INIT_ARRAY) { 538 if (lf->ctors_addr != 0) { 539 printf( 540 "%s: multiple ctor sections in %s\n", 541 __func__, filename); 542 } else { 543 lf->ctors_addr = ef->progtab[pb].addr; 544 lf->ctors_size = shdr[i].sh_size; 545 } 546 } 547 548 /* Update all symbol values with the offset. */ 549 for (j = 0; j < ef->ddbsymcnt; j++) { 550 es = &ef->ddbsymtab[j]; 551 if (es->st_shndx != i) 552 continue; 553 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 554 } 555 pb++; 556 break; 557 case SHT_REL: 558 if (shdr[shdr[i].sh_info].sh_addr == 0) 559 break; 560 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 561 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 562 ef->reltab[rl].sec = shdr[i].sh_info; 563 rl++; 564 break; 565 case SHT_RELA: 566 if (shdr[shdr[i].sh_info].sh_addr == 0) 567 break; 568 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 569 ef->relatab[ra].nrela = 570 shdr[i].sh_size / sizeof(Elf_Rela); 571 ef->relatab[ra].sec = shdr[i].sh_info; 572 ra++; 573 break; 574 } 575 } 576 if (pb != ef->nprogtab) { 577 printf("%s: lost progbits\n", filename); 578 error = ENOEXEC; 579 goto out; 580 } 581 if (rl != ef->nreltab) { 582 printf("%s: lost reltab\n", filename); 583 error = ENOEXEC; 584 goto out; 585 } 586 if (ra != ef->nrelatab) { 587 printf("%s: lost relatab\n", filename); 588 error = ENOEXEC; 589 goto out; 590 } 591 592 /* 593 * The file needs to be writeable and executable while applying 594 * relocations. Mapping protections are applied once relocation 595 * processing is complete. 596 */ 597 link_elf_protect_range(ef, (vm_offset_t)ef->address, 598 round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL); 599 600 /* Local intra-module relocations */ 601 error = link_elf_reloc_local(lf, false); 602 if (error != 0) 603 goto out; 604 *result = lf; 605 return (0); 606 607 out: 608 /* preload not done this way */ 609 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 610 return (error); 611 } 612 613 static void 614 link_elf_invoke_ctors(caddr_t addr, size_t size) 615 { 616 void (**ctor)(void); 617 size_t i, cnt; 618 619 if (addr == NULL || size == 0) 620 return; 621 cnt = size / sizeof(*ctor); 622 ctor = (void *)addr; 623 for (i = 0; i < cnt; i++) { 624 if (ctor[i] != NULL) 625 (*ctor[i])(); 626 } 627 } 628 629 static int 630 link_elf_link_preload_finish(linker_file_t lf) 631 { 632 elf_file_t ef; 633 int error; 634 635 ef = (elf_file_t)lf; 636 error = relocate_file(ef); 637 if (error) 638 return (error); 639 640 /* Notify MD code that a module is being loaded. */ 641 error = elf_cpu_load_file(lf); 642 if (error) 643 return (error); 644 645 #if defined(__i386__) || defined(__amd64__) 646 /* Now ifuncs. */ 647 error = link_elf_reloc_local(lf, true); 648 if (error != 0) 649 return (error); 650 #endif 651 652 /* Apply protections now that relocation processing is complete. */ 653 link_elf_protect(ef); 654 655 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 656 return (0); 657 } 658 659 static int 660 link_elf_load_file(linker_class_t cls, const char *filename, 661 linker_file_t *result) 662 { 663 struct nameidata *nd; 664 struct thread *td = curthread; /* XXX */ 665 Elf_Ehdr *hdr; 666 Elf_Shdr *shdr; 667 Elf_Sym *es; 668 int nbytes, i, j; 669 vm_offset_t mapbase; 670 size_t mapsize; 671 int error = 0; 672 ssize_t resid; 673 int flags; 674 elf_file_t ef; 675 linker_file_t lf; 676 int symtabindex; 677 int symstrindex; 678 int shstrindex; 679 int nsym; 680 int pb, rl, ra; 681 int alignmask; 682 683 shdr = NULL; 684 lf = NULL; 685 mapsize = 0; 686 hdr = NULL; 687 688 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK); 689 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 690 flags = FREAD; 691 error = vn_open(nd, &flags, 0, NULL); 692 if (error) { 693 free(nd, M_TEMP); 694 return error; 695 } 696 NDFREE(nd, NDF_ONLY_PNBUF); 697 if (nd->ni_vp->v_type != VREG) { 698 error = ENOEXEC; 699 goto out; 700 } 701 #ifdef MAC 702 error = mac_kld_check_load(td->td_ucred, nd->ni_vp); 703 if (error) { 704 goto out; 705 } 706 #endif 707 708 /* Read the elf header from the file. */ 709 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 710 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0, 711 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 712 &resid, td); 713 if (error) 714 goto out; 715 if (resid != 0){ 716 error = ENOEXEC; 717 goto out; 718 } 719 720 if (!IS_ELF(*hdr)) { 721 error = ENOEXEC; 722 goto out; 723 } 724 725 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 726 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 727 link_elf_error(filename, "Unsupported file layout"); 728 error = ENOEXEC; 729 goto out; 730 } 731 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 732 || hdr->e_version != EV_CURRENT) { 733 link_elf_error(filename, "Unsupported file version"); 734 error = ENOEXEC; 735 goto out; 736 } 737 if (hdr->e_type != ET_REL) { 738 error = ENOSYS; 739 goto out; 740 } 741 if (hdr->e_machine != ELF_TARG_MACH) { 742 link_elf_error(filename, "Unsupported machine"); 743 error = ENOEXEC; 744 goto out; 745 } 746 747 lf = linker_make_file(filename, &link_elf_class); 748 if (!lf) { 749 error = ENOMEM; 750 goto out; 751 } 752 ef = (elf_file_t) lf; 753 ef->nprogtab = 0; 754 ef->e_shdr = 0; 755 ef->nreltab = 0; 756 ef->nrelatab = 0; 757 758 /* Allocate and read in the section header */ 759 nbytes = hdr->e_shnum * hdr->e_shentsize; 760 if (nbytes == 0 || hdr->e_shoff == 0 || 761 hdr->e_shentsize != sizeof(Elf_Shdr)) { 762 error = ENOEXEC; 763 goto out; 764 } 765 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 766 ef->e_shdr = shdr; 767 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes, 768 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 769 NOCRED, &resid, td); 770 if (error) 771 goto out; 772 if (resid) { 773 error = ENOEXEC; 774 goto out; 775 } 776 777 /* Scan the section header for information and table sizing. */ 778 nsym = 0; 779 symtabindex = -1; 780 symstrindex = -1; 781 for (i = 0; i < hdr->e_shnum; i++) { 782 if (shdr[i].sh_size == 0) 783 continue; 784 switch (shdr[i].sh_type) { 785 case SHT_PROGBITS: 786 case SHT_NOBITS: 787 #ifdef __amd64__ 788 case SHT_X86_64_UNWIND: 789 #endif 790 case SHT_INIT_ARRAY: 791 case SHT_FINI_ARRAY: 792 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 793 break; 794 ef->nprogtab++; 795 break; 796 case SHT_SYMTAB: 797 nsym++; 798 symtabindex = i; 799 symstrindex = shdr[i].sh_link; 800 break; 801 case SHT_REL: 802 /* 803 * Ignore relocation tables for unallocated 804 * sections. 805 */ 806 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 807 break; 808 ef->nreltab++; 809 break; 810 case SHT_RELA: 811 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 812 break; 813 ef->nrelatab++; 814 break; 815 case SHT_STRTAB: 816 break; 817 } 818 } 819 if (ef->nprogtab == 0) { 820 link_elf_error(filename, "file has no contents"); 821 error = ENOEXEC; 822 goto out; 823 } 824 if (nsym != 1) { 825 /* Only allow one symbol table for now */ 826 link_elf_error(filename, 827 "file must have exactly one symbol table"); 828 error = ENOEXEC; 829 goto out; 830 } 831 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 832 shdr[symstrindex].sh_type != SHT_STRTAB) { 833 link_elf_error(filename, "file has invalid symbol strings"); 834 error = ENOEXEC; 835 goto out; 836 } 837 838 /* Allocate space for tracking the load chunks */ 839 if (ef->nprogtab != 0) 840 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 841 M_LINKER, M_WAITOK | M_ZERO); 842 if (ef->nreltab != 0) 843 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 844 M_LINKER, M_WAITOK | M_ZERO); 845 if (ef->nrelatab != 0) 846 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 847 M_LINKER, M_WAITOK | M_ZERO); 848 849 if (symtabindex == -1) { 850 link_elf_error(filename, "lost symbol table index"); 851 error = ENOEXEC; 852 goto out; 853 } 854 /* Allocate space for and load the symbol table */ 855 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 856 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 857 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab, 858 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 859 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 860 &resid, td); 861 if (error) 862 goto out; 863 if (resid != 0){ 864 error = EINVAL; 865 goto out; 866 } 867 868 /* Allocate space for and load the symbol strings */ 869 ef->ddbstrcnt = shdr[symstrindex].sh_size; 870 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 871 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab, 872 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 873 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 874 &resid, td); 875 if (error) 876 goto out; 877 if (resid != 0){ 878 error = EINVAL; 879 goto out; 880 } 881 882 /* Do we have a string table for the section names? */ 883 shstrindex = -1; 884 if (hdr->e_shstrndx != 0 && 885 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 886 shstrindex = hdr->e_shstrndx; 887 ef->shstrcnt = shdr[shstrindex].sh_size; 888 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 889 M_WAITOK); 890 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab, 891 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 892 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 893 &resid, td); 894 if (error) 895 goto out; 896 if (resid != 0){ 897 error = EINVAL; 898 goto out; 899 } 900 } 901 902 /* Size up code/data(progbits) and bss(nobits). */ 903 alignmask = 0; 904 for (i = 0; i < hdr->e_shnum; i++) { 905 if (shdr[i].sh_size == 0) 906 continue; 907 switch (shdr[i].sh_type) { 908 case SHT_PROGBITS: 909 case SHT_NOBITS: 910 #ifdef __amd64__ 911 case SHT_X86_64_UNWIND: 912 #endif 913 case SHT_INIT_ARRAY: 914 case SHT_FINI_ARRAY: 915 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 916 break; 917 alignmask = shdr[i].sh_addralign - 1; 918 mapsize += alignmask; 919 mapsize &= ~alignmask; 920 mapsize += shdr[i].sh_size; 921 break; 922 } 923 } 924 925 /* 926 * We know how much space we need for the text/data/bss/etc. 927 * This stuff needs to be in a single chunk so that profiling etc 928 * can get the bounds and gdb can associate offsets with modules 929 */ 930 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize), 931 VM_PROT_ALL, 0, thread0.td_ucred); 932 if (ef->object == NULL) { 933 error = ENOMEM; 934 goto out; 935 } 936 #if VM_NRESERVLEVEL > 0 937 vm_object_color(ef->object, 0); 938 #endif 939 940 /* 941 * In order to satisfy amd64's architectural requirements on the 942 * location of code and data in the kernel's address space, request a 943 * mapping that is above the kernel. 944 * 945 * Protections will be restricted once relocations are applied. 946 */ 947 #ifdef __amd64__ 948 mapbase = KERNBASE; 949 #else 950 mapbase = VM_MIN_KERNEL_ADDRESS; 951 #endif 952 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 953 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 954 VM_PROT_ALL, 0); 955 if (error != KERN_SUCCESS) { 956 vm_object_deallocate(ef->object); 957 ef->object = NULL; 958 error = ENOMEM; 959 goto out; 960 } 961 962 /* Wire the pages */ 963 error = vm_map_wire(kernel_map, mapbase, 964 mapbase + round_page(mapsize), 965 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 966 if (error != KERN_SUCCESS) { 967 error = ENOMEM; 968 goto out; 969 } 970 971 /* Inform the kld system about the situation */ 972 lf->address = ef->address = (caddr_t)mapbase; 973 lf->size = mapsize; 974 975 /* 976 * Now load code/data(progbits), zero bss(nobits), allocate space for 977 * and load relocs 978 */ 979 pb = 0; 980 rl = 0; 981 ra = 0; 982 alignmask = 0; 983 for (i = 0; i < hdr->e_shnum; i++) { 984 if (shdr[i].sh_size == 0) 985 continue; 986 switch (shdr[i].sh_type) { 987 case SHT_PROGBITS: 988 case SHT_NOBITS: 989 #ifdef __amd64__ 990 case SHT_X86_64_UNWIND: 991 #endif 992 case SHT_INIT_ARRAY: 993 case SHT_FINI_ARRAY: 994 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 995 break; 996 alignmask = shdr[i].sh_addralign - 1; 997 mapbase += alignmask; 998 mapbase &= ~alignmask; 999 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 1000 ef->progtab[pb].name = 1001 ef->shstrtab + shdr[i].sh_name; 1002 if (!strcmp(ef->progtab[pb].name, ".ctors") || 1003 shdr[i].sh_type == SHT_INIT_ARRAY) { 1004 if (lf->ctors_addr != 0) { 1005 printf( 1006 "%s: multiple ctor sections in %s\n", 1007 __func__, filename); 1008 } else { 1009 lf->ctors_addr = 1010 (caddr_t)mapbase; 1011 lf->ctors_size = 1012 shdr[i].sh_size; 1013 } 1014 } 1015 } else if (shdr[i].sh_type == SHT_PROGBITS) 1016 ef->progtab[pb].name = "<<PROGBITS>>"; 1017 #ifdef __amd64__ 1018 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 1019 ef->progtab[pb].name = "<<UNWIND>>"; 1020 #endif 1021 else 1022 ef->progtab[pb].name = "<<NOBITS>>"; 1023 if (ef->progtab[pb].name != NULL && 1024 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 1025 ef->progtab[pb].addr = 1026 dpcpu_alloc(shdr[i].sh_size); 1027 if (ef->progtab[pb].addr == NULL) { 1028 printf("%s: pcpu module space is out " 1029 "of space; cannot allocate %#jx " 1030 "for %s\n", __func__, 1031 (uintmax_t)shdr[i].sh_size, 1032 filename); 1033 } 1034 } 1035 #ifdef VIMAGE 1036 else if (ef->progtab[pb].name != NULL && 1037 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 1038 ef->progtab[pb].addr = 1039 vnet_data_alloc(shdr[i].sh_size); 1040 if (ef->progtab[pb].addr == NULL) { 1041 printf("%s: vnet module space is out " 1042 "of space; cannot allocate %#jx " 1043 "for %s\n", __func__, 1044 (uintmax_t)shdr[i].sh_size, 1045 filename); 1046 } 1047 } 1048 #endif 1049 else 1050 ef->progtab[pb].addr = 1051 (void *)(uintptr_t)mapbase; 1052 if (ef->progtab[pb].addr == NULL) { 1053 error = ENOSPC; 1054 goto out; 1055 } 1056 ef->progtab[pb].size = shdr[i].sh_size; 1057 ef->progtab[pb].flags = shdr[i].sh_flags; 1058 ef->progtab[pb].sec = i; 1059 if (shdr[i].sh_type == SHT_PROGBITS 1060 #ifdef __amd64__ 1061 || shdr[i].sh_type == SHT_X86_64_UNWIND 1062 #endif 1063 ) { 1064 error = vn_rdwr(UIO_READ, nd->ni_vp, 1065 ef->progtab[pb].addr, 1066 shdr[i].sh_size, shdr[i].sh_offset, 1067 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 1068 NOCRED, &resid, td); 1069 if (error) 1070 goto out; 1071 if (resid != 0){ 1072 error = EINVAL; 1073 goto out; 1074 } 1075 /* Initialize the per-cpu or vnet area. */ 1076 if (ef->progtab[pb].addr != (void *)mapbase && 1077 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 1078 dpcpu_copy(ef->progtab[pb].addr, 1079 shdr[i].sh_size); 1080 #ifdef VIMAGE 1081 else if (ef->progtab[pb].addr != 1082 (void *)mapbase && 1083 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 1084 vnet_data_copy(ef->progtab[pb].addr, 1085 shdr[i].sh_size); 1086 #endif 1087 } else 1088 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 1089 1090 /* Update all symbol values with the offset. */ 1091 for (j = 0; j < ef->ddbsymcnt; j++) { 1092 es = &ef->ddbsymtab[j]; 1093 if (es->st_shndx != i) 1094 continue; 1095 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 1096 } 1097 mapbase += shdr[i].sh_size; 1098 pb++; 1099 break; 1100 case SHT_REL: 1101 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1102 break; 1103 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 1104 M_WAITOK); 1105 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 1106 ef->reltab[rl].sec = shdr[i].sh_info; 1107 error = vn_rdwr(UIO_READ, nd->ni_vp, 1108 (void *)ef->reltab[rl].rel, 1109 shdr[i].sh_size, shdr[i].sh_offset, 1110 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1111 &resid, td); 1112 if (error) 1113 goto out; 1114 if (resid != 0){ 1115 error = EINVAL; 1116 goto out; 1117 } 1118 rl++; 1119 break; 1120 case SHT_RELA: 1121 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1122 break; 1123 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 1124 M_WAITOK); 1125 ef->relatab[ra].nrela = 1126 shdr[i].sh_size / sizeof(Elf_Rela); 1127 ef->relatab[ra].sec = shdr[i].sh_info; 1128 error = vn_rdwr(UIO_READ, nd->ni_vp, 1129 (void *)ef->relatab[ra].rela, 1130 shdr[i].sh_size, shdr[i].sh_offset, 1131 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1132 &resid, td); 1133 if (error) 1134 goto out; 1135 if (resid != 0){ 1136 error = EINVAL; 1137 goto out; 1138 } 1139 ra++; 1140 break; 1141 } 1142 } 1143 if (pb != ef->nprogtab) { 1144 link_elf_error(filename, "lost progbits"); 1145 error = ENOEXEC; 1146 goto out; 1147 } 1148 if (rl != ef->nreltab) { 1149 link_elf_error(filename, "lost reltab"); 1150 error = ENOEXEC; 1151 goto out; 1152 } 1153 if (ra != ef->nrelatab) { 1154 link_elf_error(filename, "lost relatab"); 1155 error = ENOEXEC; 1156 goto out; 1157 } 1158 if (mapbase != (vm_offset_t)ef->address + mapsize) { 1159 printf( 1160 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 1161 filename != NULL ? filename : "<none>", 1162 (u_long)mapbase, ef->address, (u_long)mapsize, 1163 (u_long)(vm_offset_t)ef->address + mapsize); 1164 error = ENOMEM; 1165 goto out; 1166 } 1167 1168 /* Local intra-module relocations */ 1169 error = link_elf_reloc_local(lf, false); 1170 if (error != 0) 1171 goto out; 1172 1173 /* Pull in dependencies */ 1174 VOP_UNLOCK(nd->ni_vp); 1175 error = linker_load_dependencies(lf); 1176 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY); 1177 if (error) 1178 goto out; 1179 1180 /* External relocations */ 1181 error = relocate_file(ef); 1182 if (error) 1183 goto out; 1184 1185 /* Notify MD code that a module is being loaded. */ 1186 error = elf_cpu_load_file(lf); 1187 if (error) 1188 goto out; 1189 1190 #if defined(__i386__) || defined(__amd64__) 1191 /* Now ifuncs. */ 1192 error = link_elf_reloc_local(lf, true); 1193 if (error != 0) 1194 goto out; 1195 #endif 1196 1197 link_elf_protect(ef); 1198 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 1199 *result = lf; 1200 1201 out: 1202 VOP_UNLOCK(nd->ni_vp); 1203 vn_close(nd->ni_vp, FREAD, td->td_ucred, td); 1204 free(nd, M_TEMP); 1205 if (error && lf) 1206 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1207 free(hdr, M_LINKER); 1208 1209 return error; 1210 } 1211 1212 static void 1213 link_elf_unload_file(linker_file_t file) 1214 { 1215 elf_file_t ef = (elf_file_t) file; 1216 u_int i; 1217 1218 /* Notify MD code that a module is being unloaded. */ 1219 elf_cpu_unload_file(file); 1220 1221 if (ef->progtab) { 1222 for (i = 0; i < ef->nprogtab; i++) { 1223 if (ef->progtab[i].size == 0) 1224 continue; 1225 if (ef->progtab[i].name == NULL) 1226 continue; 1227 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1228 dpcpu_free(ef->progtab[i].addr, 1229 ef->progtab[i].size); 1230 #ifdef VIMAGE 1231 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1232 vnet_data_free(ef->progtab[i].addr, 1233 ef->progtab[i].size); 1234 #endif 1235 } 1236 } 1237 if (ef->preloaded) { 1238 free(ef->reltab, M_LINKER); 1239 free(ef->relatab, M_LINKER); 1240 free(ef->progtab, M_LINKER); 1241 free(ef->ctftab, M_LINKER); 1242 free(ef->ctfoff, M_LINKER); 1243 free(ef->typoff, M_LINKER); 1244 if (file->pathname != NULL) 1245 preload_delete_name(file->pathname); 1246 return; 1247 } 1248 1249 for (i = 0; i < ef->nreltab; i++) 1250 free(ef->reltab[i].rel, M_LINKER); 1251 for (i = 0; i < ef->nrelatab; i++) 1252 free(ef->relatab[i].rela, M_LINKER); 1253 free(ef->reltab, M_LINKER); 1254 free(ef->relatab, M_LINKER); 1255 free(ef->progtab, M_LINKER); 1256 1257 if (ef->object != NULL) 1258 vm_map_remove(kernel_map, (vm_offset_t)ef->address, 1259 (vm_offset_t)ef->address + ptoa(ef->object->size)); 1260 free(ef->e_shdr, M_LINKER); 1261 free(ef->ddbsymtab, M_LINKER); 1262 free(ef->ddbstrtab, M_LINKER); 1263 free(ef->shstrtab, M_LINKER); 1264 free(ef->ctftab, M_LINKER); 1265 free(ef->ctfoff, M_LINKER); 1266 free(ef->typoff, M_LINKER); 1267 } 1268 1269 static const char * 1270 symbol_name(elf_file_t ef, Elf_Size r_info) 1271 { 1272 const Elf_Sym *ref; 1273 1274 if (ELF_R_SYM(r_info)) { 1275 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1276 return ef->ddbstrtab + ref->st_name; 1277 } else 1278 return NULL; 1279 } 1280 1281 static Elf_Addr 1282 findbase(elf_file_t ef, int sec) 1283 { 1284 int i; 1285 Elf_Addr base = 0; 1286 1287 for (i = 0; i < ef->nprogtab; i++) { 1288 if (sec == ef->progtab[i].sec) { 1289 base = (Elf_Addr)ef->progtab[i].addr; 1290 break; 1291 } 1292 } 1293 return base; 1294 } 1295 1296 static int 1297 relocate_file(elf_file_t ef) 1298 { 1299 const Elf_Rel *rellim; 1300 const Elf_Rel *rel; 1301 const Elf_Rela *relalim; 1302 const Elf_Rela *rela; 1303 const char *symname; 1304 const Elf_Sym *sym; 1305 int i; 1306 Elf_Size symidx; 1307 Elf_Addr base; 1308 1309 /* Perform relocations without addend if there are any: */ 1310 for (i = 0; i < ef->nreltab; i++) { 1311 rel = ef->reltab[i].rel; 1312 if (rel == NULL) { 1313 link_elf_error(ef->lf.filename, "lost a reltab!"); 1314 return (ENOEXEC); 1315 } 1316 rellim = rel + ef->reltab[i].nrel; 1317 base = findbase(ef, ef->reltab[i].sec); 1318 if (base == 0) { 1319 link_elf_error(ef->lf.filename, "lost base for reltab"); 1320 return (ENOEXEC); 1321 } 1322 for ( ; rel < rellim; rel++) { 1323 symidx = ELF_R_SYM(rel->r_info); 1324 if (symidx >= ef->ddbsymcnt) 1325 continue; 1326 sym = ef->ddbsymtab + symidx; 1327 /* Local relocs are already done */ 1328 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1329 continue; 1330 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1331 elf_obj_lookup)) { 1332 symname = symbol_name(ef, rel->r_info); 1333 printf("link_elf_obj: symbol %s undefined\n", 1334 symname); 1335 return (ENOENT); 1336 } 1337 } 1338 } 1339 1340 /* Perform relocations with addend if there are any: */ 1341 for (i = 0; i < ef->nrelatab; i++) { 1342 rela = ef->relatab[i].rela; 1343 if (rela == NULL) { 1344 link_elf_error(ef->lf.filename, "lost a relatab!"); 1345 return (ENOEXEC); 1346 } 1347 relalim = rela + ef->relatab[i].nrela; 1348 base = findbase(ef, ef->relatab[i].sec); 1349 if (base == 0) { 1350 link_elf_error(ef->lf.filename, 1351 "lost base for relatab"); 1352 return (ENOEXEC); 1353 } 1354 for ( ; rela < relalim; rela++) { 1355 symidx = ELF_R_SYM(rela->r_info); 1356 if (symidx >= ef->ddbsymcnt) 1357 continue; 1358 sym = ef->ddbsymtab + symidx; 1359 /* Local relocs are already done */ 1360 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1361 continue; 1362 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1363 elf_obj_lookup)) { 1364 symname = symbol_name(ef, rela->r_info); 1365 printf("link_elf_obj: symbol %s undefined\n", 1366 symname); 1367 return (ENOENT); 1368 } 1369 } 1370 } 1371 1372 /* 1373 * Only clean SHN_FBSD_CACHED for successful return. If we 1374 * modified symbol table for the object but found an 1375 * unresolved symbol, there is no reason to roll back. 1376 */ 1377 elf_obj_cleanup_globals_cache(ef); 1378 1379 return (0); 1380 } 1381 1382 static int 1383 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1384 { 1385 elf_file_t ef = (elf_file_t) lf; 1386 const Elf_Sym *symp; 1387 const char *strp; 1388 int i; 1389 1390 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1391 strp = ef->ddbstrtab + symp->st_name; 1392 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1393 *sym = (c_linker_sym_t) symp; 1394 return 0; 1395 } 1396 } 1397 return ENOENT; 1398 } 1399 1400 static int 1401 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1402 linker_symval_t *symval) 1403 { 1404 elf_file_t ef; 1405 const Elf_Sym *es; 1406 caddr_t val; 1407 1408 ef = (elf_file_t) lf; 1409 es = (const Elf_Sym*) sym; 1410 val = (caddr_t)es->st_value; 1411 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1412 symval->name = ef->ddbstrtab + es->st_name; 1413 val = (caddr_t)es->st_value; 1414 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1415 val = ((caddr_t (*)(void))val)(); 1416 symval->value = val; 1417 symval->size = es->st_size; 1418 return 0; 1419 } 1420 return ENOENT; 1421 } 1422 1423 static int 1424 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1425 c_linker_sym_t *sym, long *diffp) 1426 { 1427 elf_file_t ef = (elf_file_t) lf; 1428 u_long off = (uintptr_t) (void *) value; 1429 u_long diff = off; 1430 u_long st_value; 1431 const Elf_Sym *es; 1432 const Elf_Sym *best = NULL; 1433 int i; 1434 1435 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1436 if (es->st_name == 0) 1437 continue; 1438 st_value = es->st_value; 1439 if (off >= st_value) { 1440 if (off - st_value < diff) { 1441 diff = off - st_value; 1442 best = es; 1443 if (diff == 0) 1444 break; 1445 } else if (off - st_value == diff) { 1446 best = es; 1447 } 1448 } 1449 } 1450 if (best == NULL) 1451 *diffp = off; 1452 else 1453 *diffp = diff; 1454 *sym = (c_linker_sym_t) best; 1455 1456 return 0; 1457 } 1458 1459 /* 1460 * Look up a linker set on an ELF system. 1461 */ 1462 static int 1463 link_elf_lookup_set(linker_file_t lf, const char *name, 1464 void ***startp, void ***stopp, int *countp) 1465 { 1466 elf_file_t ef = (elf_file_t)lf; 1467 void **start, **stop; 1468 int i, count; 1469 1470 /* Relative to section number */ 1471 for (i = 0; i < ef->nprogtab; i++) { 1472 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1473 strcmp(ef->progtab[i].name + 4, name) == 0) { 1474 start = (void **)ef->progtab[i].addr; 1475 stop = (void **)((char *)ef->progtab[i].addr + 1476 ef->progtab[i].size); 1477 count = stop - start; 1478 if (startp) 1479 *startp = start; 1480 if (stopp) 1481 *stopp = stop; 1482 if (countp) 1483 *countp = count; 1484 return (0); 1485 } 1486 } 1487 return (ESRCH); 1488 } 1489 1490 static int 1491 link_elf_each_function_name(linker_file_t file, 1492 int (*callback)(const char *, void *), void *opaque) 1493 { 1494 elf_file_t ef = (elf_file_t)file; 1495 const Elf_Sym *symp; 1496 int i, error; 1497 1498 /* Exhaustive search */ 1499 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1500 if (symp->st_value != 0 && 1501 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1502 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1503 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1504 if (error) 1505 return (error); 1506 } 1507 } 1508 return (0); 1509 } 1510 1511 static int 1512 link_elf_each_function_nameval(linker_file_t file, 1513 linker_function_nameval_callback_t callback, void *opaque) 1514 { 1515 linker_symval_t symval; 1516 elf_file_t ef = (elf_file_t)file; 1517 const Elf_Sym* symp; 1518 int i, error; 1519 1520 /* Exhaustive search */ 1521 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1522 if (symp->st_value != 0 && 1523 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1524 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1525 error = link_elf_symbol_values(file, 1526 (c_linker_sym_t)symp, &symval); 1527 if (error) 1528 return (error); 1529 error = callback(file, i, &symval, opaque); 1530 if (error) 1531 return (error); 1532 } 1533 } 1534 return (0); 1535 } 1536 1537 static void 1538 elf_obj_cleanup_globals_cache(elf_file_t ef) 1539 { 1540 Elf_Sym *sym; 1541 Elf_Size i; 1542 1543 for (i = 0; i < ef->ddbsymcnt; i++) { 1544 sym = ef->ddbsymtab + i; 1545 if (sym->st_shndx == SHN_FBSD_CACHED) { 1546 sym->st_shndx = SHN_UNDEF; 1547 sym->st_value = 0; 1548 } 1549 } 1550 } 1551 1552 /* 1553 * Symbol lookup function that can be used when the symbol index is known (ie 1554 * in relocations). It uses the symbol index instead of doing a fully fledged 1555 * hash table based lookup when such is valid. For example for local symbols. 1556 * This is not only more efficient, it's also more correct. It's not always 1557 * the case that the symbol can be found through the hash table. 1558 */ 1559 static int 1560 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1561 { 1562 elf_file_t ef = (elf_file_t)lf; 1563 Elf_Sym *sym; 1564 const char *symbol; 1565 Elf_Addr res1; 1566 1567 /* Don't even try to lookup the symbol if the index is bogus. */ 1568 if (symidx >= ef->ddbsymcnt) { 1569 *res = 0; 1570 return (EINVAL); 1571 } 1572 1573 sym = ef->ddbsymtab + symidx; 1574 1575 /* Quick answer if there is a definition included. */ 1576 if (sym->st_shndx != SHN_UNDEF) { 1577 res1 = (Elf_Addr)sym->st_value; 1578 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1579 res1 = ((Elf_Addr (*)(void))res1)(); 1580 *res = res1; 1581 return (0); 1582 } 1583 1584 /* If we get here, then it is undefined and needs a lookup. */ 1585 switch (ELF_ST_BIND(sym->st_info)) { 1586 case STB_LOCAL: 1587 /* Local, but undefined? huh? */ 1588 *res = 0; 1589 return (EINVAL); 1590 1591 case STB_GLOBAL: 1592 case STB_WEAK: 1593 /* Relative to Data or Function name */ 1594 symbol = ef->ddbstrtab + sym->st_name; 1595 1596 /* Force a lookup failure if the symbol name is bogus. */ 1597 if (*symbol == 0) { 1598 *res = 0; 1599 return (EINVAL); 1600 } 1601 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1602 1603 /* 1604 * Cache global lookups during module relocation. The failure 1605 * case is particularly expensive for callers, who must scan 1606 * through the entire globals table doing strcmp(). Cache to 1607 * avoid doing such work repeatedly. 1608 * 1609 * After relocation is complete, undefined globals will be 1610 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1611 * above. 1612 */ 1613 if (res1 != 0) { 1614 sym->st_shndx = SHN_FBSD_CACHED; 1615 sym->st_value = res1; 1616 *res = res1; 1617 return (0); 1618 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1619 sym->st_value = 0; 1620 *res = 0; 1621 return (0); 1622 } 1623 return (EINVAL); 1624 1625 default: 1626 return (EINVAL); 1627 } 1628 } 1629 1630 static void 1631 link_elf_fix_link_set(elf_file_t ef) 1632 { 1633 static const char startn[] = "__start_"; 1634 static const char stopn[] = "__stop_"; 1635 Elf_Sym *sym; 1636 const char *sym_name, *linkset_name; 1637 Elf_Addr startp, stopp; 1638 Elf_Size symidx; 1639 int start, i; 1640 1641 startp = stopp = 0; 1642 for (symidx = 1 /* zero entry is special */; 1643 symidx < ef->ddbsymcnt; symidx++) { 1644 sym = ef->ddbsymtab + symidx; 1645 if (sym->st_shndx != SHN_UNDEF) 1646 continue; 1647 1648 sym_name = ef->ddbstrtab + sym->st_name; 1649 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1650 start = 1; 1651 linkset_name = sym_name + sizeof(startn) - 1; 1652 } 1653 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1654 start = 0; 1655 linkset_name = sym_name + sizeof(stopn) - 1; 1656 } 1657 else 1658 continue; 1659 1660 for (i = 0; i < ef->nprogtab; i++) { 1661 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1662 startp = (Elf_Addr)ef->progtab[i].addr; 1663 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1664 break; 1665 } 1666 } 1667 if (i == ef->nprogtab) 1668 continue; 1669 1670 sym->st_value = start ? startp : stopp; 1671 sym->st_shndx = i; 1672 } 1673 } 1674 1675 static int 1676 link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1677 { 1678 elf_file_t ef = (elf_file_t)lf; 1679 const Elf_Rel *rellim; 1680 const Elf_Rel *rel; 1681 const Elf_Rela *relalim; 1682 const Elf_Rela *rela; 1683 const Elf_Sym *sym; 1684 Elf_Addr base; 1685 int i; 1686 Elf_Size symidx; 1687 1688 link_elf_fix_link_set(ef); 1689 1690 /* Perform relocations without addend if there are any: */ 1691 for (i = 0; i < ef->nreltab; i++) { 1692 rel = ef->reltab[i].rel; 1693 if (rel == NULL) { 1694 link_elf_error(ef->lf.filename, "lost a reltab"); 1695 return (ENOEXEC); 1696 } 1697 rellim = rel + ef->reltab[i].nrel; 1698 base = findbase(ef, ef->reltab[i].sec); 1699 if (base == 0) { 1700 link_elf_error(ef->lf.filename, "lost base for reltab"); 1701 return (ENOEXEC); 1702 } 1703 for ( ; rel < rellim; rel++) { 1704 symidx = ELF_R_SYM(rel->r_info); 1705 if (symidx >= ef->ddbsymcnt) 1706 continue; 1707 sym = ef->ddbsymtab + symidx; 1708 /* Only do local relocs */ 1709 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1710 continue; 1711 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1712 elf_is_ifunc_reloc(rel->r_info)) != ifuncs) 1713 continue; 1714 if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1715 elf_obj_lookup) != 0) 1716 return (ENOEXEC); 1717 } 1718 } 1719 1720 /* Perform relocations with addend if there are any: */ 1721 for (i = 0; i < ef->nrelatab; i++) { 1722 rela = ef->relatab[i].rela; 1723 if (rela == NULL) { 1724 link_elf_error(ef->lf.filename, "lost a relatab!"); 1725 return (ENOEXEC); 1726 } 1727 relalim = rela + ef->relatab[i].nrela; 1728 base = findbase(ef, ef->relatab[i].sec); 1729 if (base == 0) { 1730 link_elf_error(ef->lf.filename, "lost base for reltab"); 1731 return (ENOEXEC); 1732 } 1733 for ( ; rela < relalim; rela++) { 1734 symidx = ELF_R_SYM(rela->r_info); 1735 if (symidx >= ef->ddbsymcnt) 1736 continue; 1737 sym = ef->ddbsymtab + symidx; 1738 /* Only do local relocs */ 1739 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1740 continue; 1741 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1742 elf_is_ifunc_reloc(rela->r_info)) != ifuncs) 1743 continue; 1744 if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1745 elf_obj_lookup) != 0) 1746 return (ENOEXEC); 1747 } 1748 } 1749 return (0); 1750 } 1751 1752 static long 1753 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1754 { 1755 elf_file_t ef = (elf_file_t)lf; 1756 1757 *symtab = ef->ddbsymtab; 1758 1759 if (*symtab == NULL) 1760 return (0); 1761 1762 return (ef->ddbsymcnt); 1763 } 1764 1765 static long 1766 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1767 { 1768 elf_file_t ef = (elf_file_t)lf; 1769 1770 *strtab = ef->ddbstrtab; 1771 1772 if (*strtab == NULL) 1773 return (0); 1774 1775 return (ef->ddbstrcnt); 1776 } 1777