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 73typedef 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 81typedef struct { 82 Elf_Rel *rel; 83 int nrel; 84 int sec; 85} Elf_relent; 86 87typedef struct { 88 Elf_Rela *rela; 89 int nrela; 90 int sec; 91} Elf_relaent; 92 93typedef 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 128static int link_elf_link_preload(linker_class_t cls, 129 const char *, linker_file_t *); 130static int link_elf_link_preload_finish(linker_file_t); 131static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 132static int link_elf_lookup_symbol(linker_file_t, const char *, 133 c_linker_sym_t *); 134static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 135 linker_symval_t *); 136static int link_elf_search_symbol(linker_file_t, caddr_t value, 137 c_linker_sym_t *sym, long *diffp); 138 139static void link_elf_unload_file(linker_file_t); 140static int link_elf_lookup_set(linker_file_t, const char *, 141 void ***, void ***, int *); 142static int link_elf_each_function_name(linker_file_t, 143 int (*)(const char *, void *), void *); 144static int link_elf_each_function_nameval(linker_file_t, 145 linker_function_nameval_callback_t, 146 void *); 147static int link_elf_reloc_local(linker_file_t, bool); 148static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 149static long link_elf_strtab_get(linker_file_t, caddr_t *); 150 151static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, 152 Elf_Addr *); 153 154static 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 171static 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 180static int relocate_file(elf_file_t ef); 181static void elf_obj_cleanup_globals_cache(elf_file_t); 182 183static void 184link_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 192static void 193link_elf_init(void *arg) 194{ 195 196 linker_add_class(&link_elf_class); 197} 198SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL); 199 200static void 201link_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 */ 232static void 233link_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 323static int 324link_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_INIT_ARRAY: 476 case SHT_FINI_ARRAY: 477 if (shdr[i].sh_addr == 0) 478 break; 479 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 480 if (shdr[i].sh_type == SHT_PROGBITS) 481 ef->progtab[pb].name = "<<PROGBITS>>"; 482#ifdef __amd64__ 483 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 484 ef->progtab[pb].name = "<<UNWIND>>"; 485#endif 486 else if (shdr[i].sh_type == SHT_INIT_ARRAY) 487 ef->progtab[pb].name = "<<INIT_ARRAY>>"; 488 else if (shdr[i].sh_type == SHT_FINI_ARRAY) 489 ef->progtab[pb].name = "<<FINI_ARRAY>>"; 490 else 491 ef->progtab[pb].name = "<<NOBITS>>"; 492 ef->progtab[pb].size = shdr[i].sh_size; 493 ef->progtab[pb].flags = shdr[i].sh_flags; 494 ef->progtab[pb].sec = i; 495 if (ef->shstrtab && shdr[i].sh_name != 0) 496 ef->progtab[pb].name = 497 ef->shstrtab + shdr[i].sh_name; 498 if (ef->progtab[pb].name != NULL && 499 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 500 void *dpcpu; 501 502 dpcpu = dpcpu_alloc(shdr[i].sh_size); 503 if (dpcpu == NULL) { 504 printf("%s: pcpu module space is out " 505 "of space; cannot allocate %#jx " 506 "for %s\n", __func__, 507 (uintmax_t)shdr[i].sh_size, 508 filename); 509 error = ENOSPC; 510 goto out; 511 } 512 memcpy(dpcpu, ef->progtab[pb].addr, 513 ef->progtab[pb].size); 514 dpcpu_copy(dpcpu, shdr[i].sh_size); 515 ef->progtab[pb].addr = dpcpu; 516#ifdef VIMAGE 517 } else if (ef->progtab[pb].name != NULL && 518 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 519 void *vnet_data; 520 521 vnet_data = vnet_data_alloc(shdr[i].sh_size); 522 if (vnet_data == NULL) { 523 printf("%s: vnet module space is out " 524 "of space; cannot allocate %#jx " 525 "for %s\n", __func__, 526 (uintmax_t)shdr[i].sh_size, 527 filename); 528 error = ENOSPC; 529 goto out; 530 } 531 memcpy(vnet_data, ef->progtab[pb].addr, 532 ef->progtab[pb].size); 533 vnet_data_copy(vnet_data, shdr[i].sh_size); 534 ef->progtab[pb].addr = vnet_data; 535#endif 536 } else if ((ef->progtab[pb].name != NULL && 537 strcmp(ef->progtab[pb].name, ".ctors") == 0) || 538 shdr[i].sh_type == SHT_INIT_ARRAY) { 539 if (lf->ctors_addr != 0) { 540 printf( 541 "%s: multiple ctor sections in %s\n", 542 __func__, filename); 543 } else { 544 lf->ctors_addr = ef->progtab[pb].addr; 545 lf->ctors_size = shdr[i].sh_size; 546 } 547 } 548 549 /* Update all symbol values with the offset. */ 550 for (j = 0; j < ef->ddbsymcnt; j++) { 551 es = &ef->ddbsymtab[j]; 552 if (es->st_shndx != i) 553 continue; 554 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 555 } 556 pb++; 557 break; 558 case SHT_REL: 559 if (shdr[shdr[i].sh_info].sh_addr == 0) 560 break; 561 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 562 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 563 ef->reltab[rl].sec = shdr[i].sh_info; 564 rl++; 565 break; 566 case SHT_RELA: 567 if (shdr[shdr[i].sh_info].sh_addr == 0) 568 break; 569 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 570 ef->relatab[ra].nrela = 571 shdr[i].sh_size / sizeof(Elf_Rela); 572 ef->relatab[ra].sec = shdr[i].sh_info; 573 ra++; 574 break; 575 } 576 } 577 if (pb != ef->nprogtab) { 578 printf("%s: lost progbits\n", filename); 579 error = ENOEXEC; 580 goto out; 581 } 582 if (rl != ef->nreltab) { 583 printf("%s: lost reltab\n", filename); 584 error = ENOEXEC; 585 goto out; 586 } 587 if (ra != ef->nrelatab) { 588 printf("%s: lost relatab\n", filename); 589 error = ENOEXEC; 590 goto out; 591 } 592 593 /* 594 * The file needs to be writeable and executable while applying 595 * relocations. Mapping protections are applied once relocation 596 * processing is complete. 597 */ 598 link_elf_protect_range(ef, (vm_offset_t)ef->address, 599 round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL); 600 601 /* Local intra-module relocations */ 602 error = link_elf_reloc_local(lf, false); 603 if (error != 0) 604 goto out; 605 *result = lf; 606 return (0); 607 608out: 609 /* preload not done this way */ 610 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 611 return (error); 612} 613 614static void 615link_elf_invoke_ctors(caddr_t addr, size_t size) 616{ 617 void (**ctor)(void); 618 size_t i, cnt; 619 620 if (addr == NULL || size == 0) 621 return; 622 cnt = size / sizeof(*ctor); 623 ctor = (void *)addr; 624 for (i = 0; i < cnt; i++) { 625 if (ctor[i] != NULL) 626 (*ctor[i])(); 627 } 628} 629 630static int 631link_elf_link_preload_finish(linker_file_t lf) 632{ 633 elf_file_t ef; 634 int error; 635 636 ef = (elf_file_t)lf; 637 error = relocate_file(ef); 638 if (error) 639 return (error); 640 641 /* Notify MD code that a module is being loaded. */ 642 error = elf_cpu_load_file(lf); 643 if (error) 644 return (error); 645 646#if defined(__i386__) || defined(__amd64__) 647 /* Now ifuncs. */ 648 error = link_elf_reloc_local(lf, true); 649 if (error != 0) 650 return (error); 651#endif 652 653 /* Apply protections now that relocation processing is complete. */ 654 link_elf_protect(ef); 655 656 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 657 return (0); 658} 659 660static int 661link_elf_load_file(linker_class_t cls, const char *filename, 662 linker_file_t *result) 663{ 664 struct nameidata *nd; 665 struct thread *td = curthread; /* XXX */ 666 Elf_Ehdr *hdr; 667 Elf_Shdr *shdr; 668 Elf_Sym *es; 669 int nbytes, i, j; 670 vm_offset_t mapbase; 671 size_t mapsize; 672 int error = 0; 673 ssize_t resid; 674 int flags; 675 elf_file_t ef; 676 linker_file_t lf; 677 int symtabindex; 678 int symstrindex; 679 int shstrindex; 680 int nsym; 681 int pb, rl, ra; 682 int alignmask; 683 684 shdr = NULL; 685 lf = NULL; 686 mapsize = 0; 687 hdr = NULL; 688 689 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK); 690 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 691 flags = FREAD; 692 error = vn_open(nd, &flags, 0, NULL); 693 if (error) { 694 free(nd, M_TEMP); 695 return error; 696 } 697 NDFREE(nd, NDF_ONLY_PNBUF); 698 if (nd->ni_vp->v_type != VREG) { 699 error = ENOEXEC; 700 goto out; 701 } 702#ifdef MAC 703 error = mac_kld_check_load(td->td_ucred, nd->ni_vp); 704 if (error) { 705 goto out; 706 } 707#endif 708 709 /* Read the elf header from the file. */ 710 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 711 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0, 712 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 713 &resid, td); 714 if (error) 715 goto out; 716 if (resid != 0){ 717 error = ENOEXEC; 718 goto out; 719 } 720 721 if (!IS_ELF(*hdr)) { 722 error = ENOEXEC; 723 goto out; 724 } 725 726 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 727 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 728 link_elf_error(filename, "Unsupported file layout"); 729 error = ENOEXEC; 730 goto out; 731 } 732 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 733 || hdr->e_version != EV_CURRENT) { 734 link_elf_error(filename, "Unsupported file version"); 735 error = ENOEXEC; 736 goto out; 737 } 738 if (hdr->e_type != ET_REL) { 739 error = ENOSYS; 740 goto out; 741 } 742 if (hdr->e_machine != ELF_TARG_MACH) { 743 link_elf_error(filename, "Unsupported machine"); 744 error = ENOEXEC; 745 goto out; 746 } 747 748 lf = linker_make_file(filename, &link_elf_class); 749 if (!lf) { 750 error = ENOMEM; 751 goto out; 752 } 753 ef = (elf_file_t) lf; 754 ef->nprogtab = 0; 755 ef->e_shdr = 0; 756 ef->nreltab = 0; 757 ef->nrelatab = 0; 758 759 /* Allocate and read in the section header */ 760 nbytes = hdr->e_shnum * hdr->e_shentsize; 761 if (nbytes == 0 || hdr->e_shoff == 0 || 762 hdr->e_shentsize != sizeof(Elf_Shdr)) { 763 error = ENOEXEC; 764 goto out; 765 } 766 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 767 ef->e_shdr = shdr; 768 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes, 769 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 770 NOCRED, &resid, td); 771 if (error) 772 goto out; 773 if (resid) { 774 error = ENOEXEC; 775 goto out; 776 } 777 778 /* Scan the section header for information and table sizing. */ 779 nsym = 0; 780 symtabindex = -1; 781 symstrindex = -1; 782 for (i = 0; i < hdr->e_shnum; i++) { 783 if (shdr[i].sh_size == 0) 784 continue; 785 switch (shdr[i].sh_type) { 786 case SHT_PROGBITS: 787 case SHT_NOBITS: 788#ifdef __amd64__ 789 case SHT_X86_64_UNWIND: 790#endif 791 case SHT_INIT_ARRAY: 792 case SHT_FINI_ARRAY: 793 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 794 break; 795 ef->nprogtab++; 796 break; 797 case SHT_SYMTAB: 798 nsym++; 799 symtabindex = i; 800 symstrindex = shdr[i].sh_link; 801 break; 802 case SHT_REL: 803 /* 804 * Ignore relocation tables for unallocated 805 * sections. 806 */ 807 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 808 break; 809 ef->nreltab++; 810 break; 811 case SHT_RELA: 812 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 813 break; 814 ef->nrelatab++; 815 break; 816 case SHT_STRTAB: 817 break; 818 } 819 } 820 if (ef->nprogtab == 0) { 821 link_elf_error(filename, "file has no contents"); 822 error = ENOEXEC; 823 goto out; 824 } 825 if (nsym != 1) { 826 /* Only allow one symbol table for now */ 827 link_elf_error(filename, 828 "file must have exactly one symbol table"); 829 error = ENOEXEC; 830 goto out; 831 } 832 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 833 shdr[symstrindex].sh_type != SHT_STRTAB) { 834 link_elf_error(filename, "file has invalid symbol strings"); 835 error = ENOEXEC; 836 goto out; 837 } 838 839 /* Allocate space for tracking the load chunks */ 840 if (ef->nprogtab != 0) 841 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 842 M_LINKER, M_WAITOK | M_ZERO); 843 if (ef->nreltab != 0) 844 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 845 M_LINKER, M_WAITOK | M_ZERO); 846 if (ef->nrelatab != 0) 847 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 848 M_LINKER, M_WAITOK | M_ZERO); 849 850 if (symtabindex == -1) { 851 link_elf_error(filename, "lost symbol table index"); 852 error = ENOEXEC; 853 goto out; 854 } 855 /* Allocate space for and load the symbol table */ 856 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 857 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 858 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab, 859 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 860 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 861 &resid, td); 862 if (error) 863 goto out; 864 if (resid != 0){ 865 error = EINVAL; 866 goto out; 867 } 868 869 /* Allocate space for and load the symbol strings */ 870 ef->ddbstrcnt = shdr[symstrindex].sh_size; 871 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 872 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab, 873 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 874 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 875 &resid, td); 876 if (error) 877 goto out; 878 if (resid != 0){ 879 error = EINVAL; 880 goto out; 881 } 882 883 /* Do we have a string table for the section names? */ 884 shstrindex = -1; 885 if (hdr->e_shstrndx != 0 && 886 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 887 shstrindex = hdr->e_shstrndx; 888 ef->shstrcnt = shdr[shstrindex].sh_size; 889 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 890 M_WAITOK); 891 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab, 892 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 893 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 894 &resid, td); 895 if (error) 896 goto out; 897 if (resid != 0){ 898 error = EINVAL; 899 goto out; 900 } 901 } 902 903 /* Size up code/data(progbits) and bss(nobits). */ 904 alignmask = 0; 905 for (i = 0; i < hdr->e_shnum; i++) { 906 if (shdr[i].sh_size == 0) 907 continue; 908 switch (shdr[i].sh_type) { 909 case SHT_PROGBITS: 910 case SHT_NOBITS: 911#ifdef __amd64__ 912 case SHT_X86_64_UNWIND: 913#endif 914 case SHT_INIT_ARRAY: 915 case SHT_FINI_ARRAY: 916 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 917 break; 918 alignmask = shdr[i].sh_addralign - 1; 919 mapsize += alignmask; 920 mapsize &= ~alignmask; 921 mapsize += shdr[i].sh_size; 922 break; 923 } 924 } 925 926 /* 927 * We know how much space we need for the text/data/bss/etc. 928 * This stuff needs to be in a single chunk so that profiling etc 929 * can get the bounds and gdb can associate offsets with modules 930 */ 931 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize), 932 VM_PROT_ALL, 0, thread0.td_ucred); 933 if (ef->object == NULL) { 934 error = ENOMEM; 935 goto out; 936 } 937#if VM_NRESERVLEVEL > 0 938 vm_object_color(ef->object, 0); 939#endif 940 941 /* 942 * In order to satisfy amd64's architectural requirements on the 943 * location of code and data in the kernel's address space, request a 944 * mapping that is above the kernel. 945 * 946 * Protections will be restricted once relocations are applied. 947 */ 948#ifdef __amd64__ 949 mapbase = KERNBASE; 950#else 951 mapbase = VM_MIN_KERNEL_ADDRESS; 952#endif 953 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 954 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 955 VM_PROT_ALL, 0); 956 if (error != KERN_SUCCESS) { 957 vm_object_deallocate(ef->object); 958 ef->object = NULL; 959 error = ENOMEM; 960 goto out; 961 } 962 963 /* Wire the pages */ 964 error = vm_map_wire(kernel_map, mapbase, 965 mapbase + round_page(mapsize), 966 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 967 if (error != KERN_SUCCESS) { 968 error = ENOMEM; 969 goto out; 970 } 971 972 /* Inform the kld system about the situation */ 973 lf->address = ef->address = (caddr_t)mapbase; 974 lf->size = mapsize; 975 976 /* 977 * Now load code/data(progbits), zero bss(nobits), allocate space for 978 * and load relocs 979 */ 980 pb = 0; 981 rl = 0; 982 ra = 0; 983 alignmask = 0; 984 for (i = 0; i < hdr->e_shnum; i++) { 985 if (shdr[i].sh_size == 0) 986 continue; 987 switch (shdr[i].sh_type) { 988 case SHT_PROGBITS: 989 case SHT_NOBITS: 990#ifdef __amd64__ 991 case SHT_X86_64_UNWIND: 992#endif 993 case SHT_INIT_ARRAY: 994 case SHT_FINI_ARRAY: 995 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 996 break; 997 alignmask = shdr[i].sh_addralign - 1; 998 mapbase += alignmask; 999 mapbase &= ~alignmask; 1000 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 1001 ef->progtab[pb].name = 1002 ef->shstrtab + shdr[i].sh_name; 1003 if (!strcmp(ef->progtab[pb].name, ".ctors") || 1004 shdr[i].sh_type == SHT_INIT_ARRAY) { 1005 if (lf->ctors_addr != 0) { 1006 printf( 1007 "%s: multiple ctor sections in %s\n", 1008 __func__, filename); 1009 } else { 1010 lf->ctors_addr = 1011 (caddr_t)mapbase; 1012 lf->ctors_size = 1013 shdr[i].sh_size; 1014 } 1015 } 1016 } else if (shdr[i].sh_type == SHT_PROGBITS) 1017 ef->progtab[pb].name = "<<PROGBITS>>"; 1018#ifdef __amd64__ 1019 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 1020 ef->progtab[pb].name = "<<UNWIND>>"; 1021#endif 1022 else 1023 ef->progtab[pb].name = "<<NOBITS>>"; 1024 if (ef->progtab[pb].name != NULL && 1025 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 1026 ef->progtab[pb].addr = 1027 dpcpu_alloc(shdr[i].sh_size); 1028 if (ef->progtab[pb].addr == NULL) { 1029 printf("%s: pcpu module space is out " 1030 "of space; cannot allocate %#jx " 1031 "for %s\n", __func__, 1032 (uintmax_t)shdr[i].sh_size, 1033 filename); 1034 } 1035 } 1036#ifdef VIMAGE 1037 else if (ef->progtab[pb].name != NULL && 1038 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 1039 ef->progtab[pb].addr = 1040 vnet_data_alloc(shdr[i].sh_size); 1041 if (ef->progtab[pb].addr == NULL) { 1042 printf("%s: vnet module space is out " 1043 "of space; cannot allocate %#jx " 1044 "for %s\n", __func__, 1045 (uintmax_t)shdr[i].sh_size, 1046 filename); 1047 } 1048 } 1049#endif 1050 else 1051 ef->progtab[pb].addr = 1052 (void *)(uintptr_t)mapbase; 1053 if (ef->progtab[pb].addr == NULL) { 1054 error = ENOSPC; 1055 goto out; 1056 } 1057 ef->progtab[pb].size = shdr[i].sh_size; 1058 ef->progtab[pb].flags = shdr[i].sh_flags; 1059 ef->progtab[pb].sec = i; 1060 if (shdr[i].sh_type == SHT_PROGBITS 1061#ifdef __amd64__ 1062 || shdr[i].sh_type == SHT_X86_64_UNWIND 1063#endif 1064 ) { 1065 error = vn_rdwr(UIO_READ, nd->ni_vp, 1066 ef->progtab[pb].addr, 1067 shdr[i].sh_size, shdr[i].sh_offset, 1068 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 1069 NOCRED, &resid, td); 1070 if (error) 1071 goto out; 1072 if (resid != 0){ 1073 error = EINVAL; 1074 goto out; 1075 } 1076 /* Initialize the per-cpu or vnet area. */ 1077 if (ef->progtab[pb].addr != (void *)mapbase && 1078 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 1079 dpcpu_copy(ef->progtab[pb].addr, 1080 shdr[i].sh_size); 1081#ifdef VIMAGE 1082 else if (ef->progtab[pb].addr != 1083 (void *)mapbase && 1084 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 1085 vnet_data_copy(ef->progtab[pb].addr, 1086 shdr[i].sh_size); 1087#endif 1088 } else 1089 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 1090 1091 /* Update all symbol values with the offset. */ 1092 for (j = 0; j < ef->ddbsymcnt; j++) { 1093 es = &ef->ddbsymtab[j]; 1094 if (es->st_shndx != i) 1095 continue; 1096 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 1097 } 1098 mapbase += shdr[i].sh_size; 1099 pb++; 1100 break; 1101 case SHT_REL: 1102 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1103 break; 1104 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 1105 M_WAITOK); 1106 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 1107 ef->reltab[rl].sec = shdr[i].sh_info; 1108 error = vn_rdwr(UIO_READ, nd->ni_vp, 1109 (void *)ef->reltab[rl].rel, 1110 shdr[i].sh_size, shdr[i].sh_offset, 1111 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1112 &resid, td); 1113 if (error) 1114 goto out; 1115 if (resid != 0){ 1116 error = EINVAL; 1117 goto out; 1118 } 1119 rl++; 1120 break; 1121 case SHT_RELA: 1122 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1123 break; 1124 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 1125 M_WAITOK); 1126 ef->relatab[ra].nrela = 1127 shdr[i].sh_size / sizeof(Elf_Rela); 1128 ef->relatab[ra].sec = shdr[i].sh_info; 1129 error = vn_rdwr(UIO_READ, nd->ni_vp, 1130 (void *)ef->relatab[ra].rela, 1131 shdr[i].sh_size, shdr[i].sh_offset, 1132 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1133 &resid, td); 1134 if (error) 1135 goto out; 1136 if (resid != 0){ 1137 error = EINVAL; 1138 goto out; 1139 } 1140 ra++; 1141 break; 1142 } 1143 } 1144 if (pb != ef->nprogtab) { 1145 link_elf_error(filename, "lost progbits"); 1146 error = ENOEXEC; 1147 goto out; 1148 } 1149 if (rl != ef->nreltab) { 1150 link_elf_error(filename, "lost reltab"); 1151 error = ENOEXEC; 1152 goto out; 1153 } 1154 if (ra != ef->nrelatab) { 1155 link_elf_error(filename, "lost relatab"); 1156 error = ENOEXEC; 1157 goto out; 1158 } 1159 if (mapbase != (vm_offset_t)ef->address + mapsize) { 1160 printf( 1161 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 1162 filename != NULL ? filename : "<none>", 1163 (u_long)mapbase, ef->address, (u_long)mapsize, 1164 (u_long)(vm_offset_t)ef->address + mapsize); 1165 error = ENOMEM; 1166 goto out; 1167 } 1168 1169 /* Local intra-module relocations */ 1170 error = link_elf_reloc_local(lf, false); 1171 if (error != 0) 1172 goto out; 1173 1174 /* Pull in dependencies */ 1175 VOP_UNLOCK(nd->ni_vp); 1176 error = linker_load_dependencies(lf); 1177 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY); 1178 if (error) 1179 goto out; 1180 1181 /* External relocations */ 1182 error = relocate_file(ef); 1183 if (error) 1184 goto out; 1185 1186 /* Notify MD code that a module is being loaded. */ 1187 error = elf_cpu_load_file(lf); 1188 if (error) 1189 goto out; 1190 1191#if defined(__i386__) || defined(__amd64__) 1192 /* Now ifuncs. */ 1193 error = link_elf_reloc_local(lf, true); 1194 if (error != 0) 1195 goto out; 1196#endif 1197 1198 link_elf_protect(ef); 1199 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 1200 *result = lf; 1201 1202out: 1203 VOP_UNLOCK(nd->ni_vp); 1204 vn_close(nd->ni_vp, FREAD, td->td_ucred, td); 1205 free(nd, M_TEMP); 1206 if (error && lf) 1207 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1208 free(hdr, M_LINKER); 1209 1210 return error; 1211} 1212 1213static void 1214link_elf_unload_file(linker_file_t file) 1215{ 1216 elf_file_t ef = (elf_file_t) file; 1217 u_int i; 1218 1219 /* Notify MD code that a module is being unloaded. */ 1220 elf_cpu_unload_file(file); 1221 1222 if (ef->progtab) { 1223 for (i = 0; i < ef->nprogtab; i++) { 1224 if (ef->progtab[i].size == 0) 1225 continue; 1226 if (ef->progtab[i].name == NULL) 1227 continue; 1228 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1229 dpcpu_free(ef->progtab[i].addr, 1230 ef->progtab[i].size); 1231#ifdef VIMAGE 1232 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1233 vnet_data_free(ef->progtab[i].addr, 1234 ef->progtab[i].size); 1235#endif 1236 } 1237 } 1238 if (ef->preloaded) { 1239 free(ef->reltab, M_LINKER); 1240 free(ef->relatab, M_LINKER); 1241 free(ef->progtab, M_LINKER); 1242 free(ef->ctftab, M_LINKER); 1243 free(ef->ctfoff, M_LINKER); 1244 free(ef->typoff, M_LINKER); 1245 if (file->pathname != NULL) 1246 preload_delete_name(file->pathname); 1247 return; 1248 } 1249 1250 for (i = 0; i < ef->nreltab; i++) 1251 free(ef->reltab[i].rel, M_LINKER); 1252 for (i = 0; i < ef->nrelatab; i++) 1253 free(ef->relatab[i].rela, M_LINKER); 1254 free(ef->reltab, M_LINKER); 1255 free(ef->relatab, M_LINKER); 1256 free(ef->progtab, M_LINKER); 1257 1258 if (ef->object != NULL) 1259 vm_map_remove(kernel_map, (vm_offset_t)ef->address, 1260 (vm_offset_t)ef->address + ptoa(ef->object->size)); 1261 free(ef->e_shdr, M_LINKER); 1262 free(ef->ddbsymtab, M_LINKER); 1263 free(ef->ddbstrtab, M_LINKER); 1264 free(ef->shstrtab, M_LINKER); 1265 free(ef->ctftab, M_LINKER); 1266 free(ef->ctfoff, M_LINKER); 1267 free(ef->typoff, M_LINKER); 1268} 1269 1270static const char * 1271symbol_name(elf_file_t ef, Elf_Size r_info) 1272{ 1273 const Elf_Sym *ref; 1274 1275 if (ELF_R_SYM(r_info)) { 1276 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1277 return ef->ddbstrtab + ref->st_name; 1278 } else 1279 return NULL; 1280} 1281 1282static Elf_Addr 1283findbase(elf_file_t ef, int sec) 1284{ 1285 int i; 1286 Elf_Addr base = 0; 1287 1288 for (i = 0; i < ef->nprogtab; i++) { 1289 if (sec == ef->progtab[i].sec) { 1290 base = (Elf_Addr)ef->progtab[i].addr; 1291 break; 1292 } 1293 } 1294 return base; 1295} 1296 1297static int 1298relocate_file(elf_file_t ef) 1299{ 1300 const Elf_Rel *rellim; 1301 const Elf_Rel *rel; 1302 const Elf_Rela *relalim; 1303 const Elf_Rela *rela; 1304 const char *symname; 1305 const Elf_Sym *sym; 1306 int i; 1307 Elf_Size symidx; 1308 Elf_Addr base; 1309 1310 /* Perform relocations without addend if there are any: */ 1311 for (i = 0; i < ef->nreltab; i++) { 1312 rel = ef->reltab[i].rel; 1313 if (rel == NULL) { 1314 link_elf_error(ef->lf.filename, "lost a reltab!"); 1315 return (ENOEXEC); 1316 } 1317 rellim = rel + ef->reltab[i].nrel; 1318 base = findbase(ef, ef->reltab[i].sec); 1319 if (base == 0) { 1320 link_elf_error(ef->lf.filename, "lost base for reltab"); 1321 return (ENOEXEC); 1322 } 1323 for ( ; rel < rellim; rel++) { 1324 symidx = ELF_R_SYM(rel->r_info); 1325 if (symidx >= ef->ddbsymcnt) 1326 continue; 1327 sym = ef->ddbsymtab + symidx; 1328 /* Local relocs are already done */ 1329 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1330 continue; 1331 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1332 elf_obj_lookup)) { 1333 symname = symbol_name(ef, rel->r_info); 1334 printf("link_elf_obj: symbol %s undefined\n", 1335 symname); 1336 return (ENOENT); 1337 } 1338 } 1339 } 1340 1341 /* Perform relocations with addend if there are any: */ 1342 for (i = 0; i < ef->nrelatab; i++) { 1343 rela = ef->relatab[i].rela; 1344 if (rela == NULL) { 1345 link_elf_error(ef->lf.filename, "lost a relatab!"); 1346 return (ENOEXEC); 1347 } 1348 relalim = rela + ef->relatab[i].nrela; 1349 base = findbase(ef, ef->relatab[i].sec); 1350 if (base == 0) { 1351 link_elf_error(ef->lf.filename, 1352 "lost base for relatab"); 1353 return (ENOEXEC); 1354 } 1355 for ( ; rela < relalim; rela++) { 1356 symidx = ELF_R_SYM(rela->r_info); 1357 if (symidx >= ef->ddbsymcnt) 1358 continue; 1359 sym = ef->ddbsymtab + symidx; 1360 /* Local relocs are already done */ 1361 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1362 continue; 1363 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1364 elf_obj_lookup)) { 1365 symname = symbol_name(ef, rela->r_info); 1366 printf("link_elf_obj: symbol %s undefined\n", 1367 symname); 1368 return (ENOENT); 1369 } 1370 } 1371 } 1372 1373 /* 1374 * Only clean SHN_FBSD_CACHED for successful return. If we 1375 * modified symbol table for the object but found an 1376 * unresolved symbol, there is no reason to roll back. 1377 */ 1378 elf_obj_cleanup_globals_cache(ef); 1379 1380 return (0); 1381} 1382 1383static int 1384link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1385{ 1386 elf_file_t ef = (elf_file_t) lf; 1387 const Elf_Sym *symp; 1388 const char *strp; 1389 int i; 1390 1391 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1392 strp = ef->ddbstrtab + symp->st_name; 1393 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1394 *sym = (c_linker_sym_t) symp; 1395 return 0; 1396 } 1397 } 1398 return ENOENT; 1399} 1400 1401static int 1402link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1403 linker_symval_t *symval) 1404{ 1405 elf_file_t ef; 1406 const Elf_Sym *es; 1407 caddr_t val; 1408 1409 ef = (elf_file_t) lf; 1410 es = (const Elf_Sym*) sym; 1411 val = (caddr_t)es->st_value; 1412 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1413 symval->name = ef->ddbstrtab + es->st_name; 1414 val = (caddr_t)es->st_value; 1415 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1416 val = ((caddr_t (*)(void))val)(); 1417 symval->value = val; 1418 symval->size = es->st_size; 1419 return 0; 1420 } 1421 return ENOENT; 1422} 1423 1424static int 1425link_elf_search_symbol(linker_file_t lf, caddr_t value, 1426 c_linker_sym_t *sym, long *diffp) 1427{ 1428 elf_file_t ef = (elf_file_t) lf; 1429 u_long off = (uintptr_t) (void *) value; 1430 u_long diff = off; 1431 u_long st_value; 1432 const Elf_Sym *es; 1433 const Elf_Sym *best = NULL; 1434 int i; 1435 1436 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1437 if (es->st_name == 0) 1438 continue; 1439 st_value = es->st_value; 1440 if (off >= st_value) { 1441 if (off - st_value < diff) { 1442 diff = off - st_value; 1443 best = es; 1444 if (diff == 0) 1445 break; 1446 } else if (off - st_value == diff) { 1447 best = es; 1448 } 1449 } 1450 } 1451 if (best == NULL) 1452 *diffp = off; 1453 else 1454 *diffp = diff; 1455 *sym = (c_linker_sym_t) best; 1456 1457 return 0; 1458} 1459 1460/* 1461 * Look up a linker set on an ELF system. 1462 */ 1463static int 1464link_elf_lookup_set(linker_file_t lf, const char *name, 1465 void ***startp, void ***stopp, int *countp) 1466{ 1467 elf_file_t ef = (elf_file_t)lf; 1468 void **start, **stop; 1469 int i, count; 1470 1471 /* Relative to section number */ 1472 for (i = 0; i < ef->nprogtab; i++) { 1473 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1474 strcmp(ef->progtab[i].name + 4, name) == 0) { 1475 start = (void **)ef->progtab[i].addr; 1476 stop = (void **)((char *)ef->progtab[i].addr + 1477 ef->progtab[i].size); 1478 count = stop - start; 1479 if (startp) 1480 *startp = start; 1481 if (stopp) 1482 *stopp = stop; 1483 if (countp) 1484 *countp = count; 1485 return (0); 1486 } 1487 } 1488 return (ESRCH); 1489} 1490 1491static int 1492link_elf_each_function_name(linker_file_t file, 1493 int (*callback)(const char *, void *), void *opaque) 1494{ 1495 elf_file_t ef = (elf_file_t)file; 1496 const Elf_Sym *symp; 1497 int i, error; 1498 1499 /* Exhaustive search */ 1500 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1501 if (symp->st_value != 0 && 1502 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1503 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1504 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1505 if (error) 1506 return (error); 1507 } 1508 } 1509 return (0); 1510} 1511 1512static int 1513link_elf_each_function_nameval(linker_file_t file, 1514 linker_function_nameval_callback_t callback, void *opaque) 1515{ 1516 linker_symval_t symval; 1517 elf_file_t ef = (elf_file_t)file; 1518 const Elf_Sym* symp; 1519 int i, error; 1520 1521 /* Exhaustive search */ 1522 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1523 if (symp->st_value != 0 && 1524 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1525 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1526 error = link_elf_symbol_values(file, 1527 (c_linker_sym_t)symp, &symval); 1528 if (error) 1529 return (error); 1530 error = callback(file, i, &symval, opaque); 1531 if (error) 1532 return (error); 1533 } 1534 } 1535 return (0); 1536} 1537 1538static void 1539elf_obj_cleanup_globals_cache(elf_file_t ef) 1540{ 1541 Elf_Sym *sym; 1542 Elf_Size i; 1543 1544 for (i = 0; i < ef->ddbsymcnt; i++) { 1545 sym = ef->ddbsymtab + i; 1546 if (sym->st_shndx == SHN_FBSD_CACHED) { 1547 sym->st_shndx = SHN_UNDEF; 1548 sym->st_value = 0; 1549 } 1550 } 1551} 1552 1553/* 1554 * Symbol lookup function that can be used when the symbol index is known (ie 1555 * in relocations). It uses the symbol index instead of doing a fully fledged 1556 * hash table based lookup when such is valid. For example for local symbols. 1557 * This is not only more efficient, it's also more correct. It's not always 1558 * the case that the symbol can be found through the hash table. 1559 */ 1560static int 1561elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1562{ 1563 elf_file_t ef = (elf_file_t)lf; 1564 Elf_Sym *sym; 1565 const char *symbol; 1566 Elf_Addr res1; 1567 1568 /* Don't even try to lookup the symbol if the index is bogus. */ 1569 if (symidx >= ef->ddbsymcnt) { 1570 *res = 0; 1571 return (EINVAL); 1572 } 1573 1574 sym = ef->ddbsymtab + symidx; 1575 1576 /* Quick answer if there is a definition included. */ 1577 if (sym->st_shndx != SHN_UNDEF) { 1578 res1 = (Elf_Addr)sym->st_value; 1579 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1580 res1 = ((Elf_Addr (*)(void))res1)(); 1581 *res = res1; 1582 return (0); 1583 } 1584 1585 /* If we get here, then it is undefined and needs a lookup. */ 1586 switch (ELF_ST_BIND(sym->st_info)) { 1587 case STB_LOCAL: 1588 /* Local, but undefined? huh? */ 1589 *res = 0; 1590 return (EINVAL); 1591 1592 case STB_GLOBAL: 1593 case STB_WEAK: 1594 /* Relative to Data or Function name */ 1595 symbol = ef->ddbstrtab + sym->st_name; 1596 1597 /* Force a lookup failure if the symbol name is bogus. */ 1598 if (*symbol == 0) { 1599 *res = 0; 1600 return (EINVAL); 1601 } 1602 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1603 1604 /* 1605 * Cache global lookups during module relocation. The failure 1606 * case is particularly expensive for callers, who must scan 1607 * through the entire globals table doing strcmp(). Cache to 1608 * avoid doing such work repeatedly. 1609 * 1610 * After relocation is complete, undefined globals will be 1611 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1612 * above. 1613 */ 1614 if (res1 != 0) { 1615 sym->st_shndx = SHN_FBSD_CACHED; 1616 sym->st_value = res1; 1617 *res = res1; 1618 return (0); 1619 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1620 sym->st_value = 0; 1621 *res = 0; 1622 return (0); 1623 } 1624 return (EINVAL); 1625 1626 default: 1627 return (EINVAL); 1628 } 1629} 1630 1631static void 1632link_elf_fix_link_set(elf_file_t ef) 1633{ 1634 static const char startn[] = "__start_"; 1635 static const char stopn[] = "__stop_"; 1636 Elf_Sym *sym; 1637 const char *sym_name, *linkset_name; 1638 Elf_Addr startp, stopp; 1639 Elf_Size symidx; 1640 int start, i; 1641 1642 startp = stopp = 0; 1643 for (symidx = 1 /* zero entry is special */; 1644 symidx < ef->ddbsymcnt; symidx++) { 1645 sym = ef->ddbsymtab + symidx; 1646 if (sym->st_shndx != SHN_UNDEF) 1647 continue; 1648 1649 sym_name = ef->ddbstrtab + sym->st_name; 1650 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1651 start = 1; 1652 linkset_name = sym_name + sizeof(startn) - 1; 1653 } 1654 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1655 start = 0; 1656 linkset_name = sym_name + sizeof(stopn) - 1; 1657 } 1658 else 1659 continue; 1660 1661 for (i = 0; i < ef->nprogtab; i++) { 1662 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1663 startp = (Elf_Addr)ef->progtab[i].addr; 1664 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1665 break; 1666 } 1667 } 1668 if (i == ef->nprogtab) 1669 continue; 1670 1671 sym->st_value = start ? startp : stopp; 1672 sym->st_shndx = i; 1673 } 1674} 1675 1676static int 1677link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1678{ 1679 elf_file_t ef = (elf_file_t)lf; 1680 const Elf_Rel *rellim; 1681 const Elf_Rel *rel; 1682 const Elf_Rela *relalim; 1683 const Elf_Rela *rela; 1684 const Elf_Sym *sym; 1685 Elf_Addr base; 1686 int i; 1687 Elf_Size symidx; 1688 1689 link_elf_fix_link_set(ef); 1690 1691 /* Perform relocations without addend if there are any: */ 1692 for (i = 0; i < ef->nreltab; i++) { 1693 rel = ef->reltab[i].rel; 1694 if (rel == NULL) { 1695 link_elf_error(ef->lf.filename, "lost a reltab"); 1696 return (ENOEXEC); 1697 } 1698 rellim = rel + ef->reltab[i].nrel; 1699 base = findbase(ef, ef->reltab[i].sec); 1700 if (base == 0) { 1701 link_elf_error(ef->lf.filename, "lost base for reltab"); 1702 return (ENOEXEC); 1703 } 1704 for ( ; rel < rellim; rel++) { 1705 symidx = ELF_R_SYM(rel->r_info); 1706 if (symidx >= ef->ddbsymcnt) 1707 continue; 1708 sym = ef->ddbsymtab + symidx; 1709 /* Only do local relocs */ 1710 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1711 continue; 1712 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1713 elf_is_ifunc_reloc(rel->r_info)) != ifuncs) 1714 continue; 1715 if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1716 elf_obj_lookup) != 0) 1717 return (ENOEXEC); 1718 } 1719 } 1720 1721 /* Perform relocations with addend if there are any: */ 1722 for (i = 0; i < ef->nrelatab; i++) { 1723 rela = ef->relatab[i].rela; 1724 if (rela == NULL) { 1725 link_elf_error(ef->lf.filename, "lost a relatab!"); 1726 return (ENOEXEC); 1727 } 1728 relalim = rela + ef->relatab[i].nrela; 1729 base = findbase(ef, ef->relatab[i].sec); 1730 if (base == 0) { 1731 link_elf_error(ef->lf.filename, "lost base for reltab"); 1732 return (ENOEXEC); 1733 } 1734 for ( ; rela < relalim; rela++) { 1735 symidx = ELF_R_SYM(rela->r_info); 1736 if (symidx >= ef->ddbsymcnt) 1737 continue; 1738 sym = ef->ddbsymtab + symidx; 1739 /* Only do local relocs */ 1740 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1741 continue; 1742 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1743 elf_is_ifunc_reloc(rela->r_info)) != ifuncs) 1744 continue; 1745 if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1746 elf_obj_lookup) != 0) 1747 return (ENOEXEC); 1748 } 1749 } 1750 return (0); 1751} 1752 1753static long 1754link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1755{ 1756 elf_file_t ef = (elf_file_t)lf; 1757 1758 *symtab = ef->ddbsymtab; 1759 1760 if (*symtab == NULL) 1761 return (0); 1762 1763 return (ef->ddbsymcnt); 1764} 1765 1766static long 1767link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1768{ 1769 elf_file_t ef = (elf_file_t)lf; 1770 1771 *strtab = ef->ddbstrtab; 1772 1773 if (*strtab == NULL) 1774 return (0); 1775 1776 return (ef->ddbstrcnt); 1777} 1778