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_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 } else if ((ef->progtab[pb].name != NULL && 548 strcmp(ef->progtab[pb].name, ".dtors") == 0) || 549 shdr[i].sh_type == SHT_FINI_ARRAY) { 550 if (lf->dtors_addr != 0) { 551 printf( 552 "%s: multiple dtor sections in %s\n", 553 __func__, filename); 554 } else { 555 lf->dtors_addr = ef->progtab[pb].addr; 556 lf->dtors_size = shdr[i].sh_size; 557 } 558 } 559 560 /* Update all symbol values with the offset. */ 561 for (j = 0; j < ef->ddbsymcnt; j++) { 562 es = &ef->ddbsymtab[j]; 563 if (es->st_shndx != i) 564 continue; 565 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 566 } 567 pb++; 568 break; 569 case SHT_REL: 570 if (shdr[shdr[i].sh_info].sh_addr == 0) 571 break; 572 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 573 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 574 ef->reltab[rl].sec = shdr[i].sh_info; 575 rl++; 576 break; 577 case SHT_RELA: 578 if (shdr[shdr[i].sh_info].sh_addr == 0) 579 break; 580 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 581 ef->relatab[ra].nrela = 582 shdr[i].sh_size / sizeof(Elf_Rela); 583 ef->relatab[ra].sec = shdr[i].sh_info; 584 ra++; 585 break; 586 } 587 } 588 if (pb != ef->nprogtab) { 589 printf("%s: lost progbits\n", filename); 590 error = ENOEXEC; 591 goto out; 592 } 593 if (rl != ef->nreltab) { 594 printf("%s: lost reltab\n", filename); 595 error = ENOEXEC; 596 goto out; 597 } 598 if (ra != ef->nrelatab) { 599 printf("%s: lost relatab\n", filename); 600 error = ENOEXEC; 601 goto out; 602 } 603 604 /* 605 * The file needs to be writeable and executable while applying 606 * relocations. Mapping protections are applied once relocation 607 * processing is complete. 608 */ 609 link_elf_protect_range(ef, (vm_offset_t)ef->address, 610 round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL); 611 612 /* Local intra-module relocations */ 613 error = link_elf_reloc_local(lf, false); 614 if (error != 0) 615 goto out; 616 *result = lf; 617 return (0); 618 619 out: 620 /* preload not done this way */ 621 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 622 return (error); 623 } 624 625 static void 626 link_elf_invoke_cbs(caddr_t addr, size_t size) 627 { 628 void (**ctor)(void); 629 size_t i, cnt; 630 631 if (addr == NULL || size == 0) 632 return; 633 cnt = size / sizeof(*ctor); 634 ctor = (void *)addr; 635 for (i = 0; i < cnt; i++) { 636 if (ctor[i] != NULL) 637 (*ctor[i])(); 638 } 639 } 640 641 static int 642 link_elf_link_preload_finish(linker_file_t lf) 643 { 644 elf_file_t ef; 645 int error; 646 647 ef = (elf_file_t)lf; 648 error = relocate_file(ef); 649 if (error) 650 return (error); 651 652 /* Notify MD code that a module is being loaded. */ 653 error = elf_cpu_load_file(lf); 654 if (error) 655 return (error); 656 657 #if defined(__i386__) || defined(__amd64__) 658 /* Now ifuncs. */ 659 error = link_elf_reloc_local(lf, true); 660 if (error != 0) 661 return (error); 662 #endif 663 664 /* Apply protections now that relocation processing is complete. */ 665 link_elf_protect(ef); 666 667 link_elf_invoke_cbs(lf->ctors_addr, lf->ctors_size); 668 return (0); 669 } 670 671 static int 672 link_elf_load_file(linker_class_t cls, const char *filename, 673 linker_file_t *result) 674 { 675 struct nameidata *nd; 676 struct thread *td = curthread; /* XXX */ 677 Elf_Ehdr *hdr; 678 Elf_Shdr *shdr; 679 Elf_Sym *es; 680 int nbytes, i, j; 681 vm_offset_t mapbase; 682 size_t mapsize; 683 int error = 0; 684 ssize_t resid; 685 int flags; 686 elf_file_t ef; 687 linker_file_t lf; 688 int symtabindex; 689 int symstrindex; 690 int shstrindex; 691 int nsym; 692 int pb, rl, ra; 693 int alignmask; 694 695 shdr = NULL; 696 lf = NULL; 697 mapsize = 0; 698 hdr = NULL; 699 700 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK); 701 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename); 702 flags = FREAD; 703 error = vn_open(nd, &flags, 0, NULL); 704 if (error) { 705 free(nd, M_TEMP); 706 return error; 707 } 708 NDFREE(nd, NDF_ONLY_PNBUF); 709 if (nd->ni_vp->v_type != VREG) { 710 error = ENOEXEC; 711 goto out; 712 } 713 #ifdef MAC 714 error = mac_kld_check_load(td->td_ucred, nd->ni_vp); 715 if (error) { 716 goto out; 717 } 718 #endif 719 720 /* Read the elf header from the file. */ 721 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 722 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0, 723 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 724 &resid, td); 725 if (error) 726 goto out; 727 if (resid != 0){ 728 error = ENOEXEC; 729 goto out; 730 } 731 732 if (!IS_ELF(*hdr)) { 733 error = ENOEXEC; 734 goto out; 735 } 736 737 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 738 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 739 link_elf_error(filename, "Unsupported file layout"); 740 error = ENOEXEC; 741 goto out; 742 } 743 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 744 || hdr->e_version != EV_CURRENT) { 745 link_elf_error(filename, "Unsupported file version"); 746 error = ENOEXEC; 747 goto out; 748 } 749 if (hdr->e_type != ET_REL) { 750 error = ENOSYS; 751 goto out; 752 } 753 if (hdr->e_machine != ELF_TARG_MACH) { 754 link_elf_error(filename, "Unsupported machine"); 755 error = ENOEXEC; 756 goto out; 757 } 758 759 lf = linker_make_file(filename, &link_elf_class); 760 if (!lf) { 761 error = ENOMEM; 762 goto out; 763 } 764 ef = (elf_file_t) lf; 765 ef->nprogtab = 0; 766 ef->e_shdr = 0; 767 ef->nreltab = 0; 768 ef->nrelatab = 0; 769 770 /* Allocate and read in the section header */ 771 nbytes = hdr->e_shnum * hdr->e_shentsize; 772 if (nbytes == 0 || hdr->e_shoff == 0 || 773 hdr->e_shentsize != sizeof(Elf_Shdr)) { 774 error = ENOEXEC; 775 goto out; 776 } 777 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 778 ef->e_shdr = shdr; 779 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes, 780 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 781 NOCRED, &resid, td); 782 if (error) 783 goto out; 784 if (resid) { 785 error = ENOEXEC; 786 goto out; 787 } 788 789 /* Scan the section header for information and table sizing. */ 790 nsym = 0; 791 symtabindex = -1; 792 symstrindex = -1; 793 for (i = 0; i < hdr->e_shnum; i++) { 794 if (shdr[i].sh_size == 0) 795 continue; 796 switch (shdr[i].sh_type) { 797 case SHT_PROGBITS: 798 case SHT_NOBITS: 799 #ifdef __amd64__ 800 case SHT_X86_64_UNWIND: 801 #endif 802 case SHT_INIT_ARRAY: 803 case SHT_FINI_ARRAY: 804 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 805 break; 806 ef->nprogtab++; 807 break; 808 case SHT_SYMTAB: 809 nsym++; 810 symtabindex = i; 811 symstrindex = shdr[i].sh_link; 812 break; 813 case SHT_REL: 814 /* 815 * Ignore relocation tables for unallocated 816 * sections. 817 */ 818 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 819 break; 820 ef->nreltab++; 821 break; 822 case SHT_RELA: 823 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 824 break; 825 ef->nrelatab++; 826 break; 827 case SHT_STRTAB: 828 break; 829 } 830 } 831 if (ef->nprogtab == 0) { 832 link_elf_error(filename, "file has no contents"); 833 error = ENOEXEC; 834 goto out; 835 } 836 if (nsym != 1) { 837 /* Only allow one symbol table for now */ 838 link_elf_error(filename, 839 "file must have exactly one symbol table"); 840 error = ENOEXEC; 841 goto out; 842 } 843 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 844 shdr[symstrindex].sh_type != SHT_STRTAB) { 845 link_elf_error(filename, "file has invalid symbol strings"); 846 error = ENOEXEC; 847 goto out; 848 } 849 850 /* Allocate space for tracking the load chunks */ 851 if (ef->nprogtab != 0) 852 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 853 M_LINKER, M_WAITOK | M_ZERO); 854 if (ef->nreltab != 0) 855 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 856 M_LINKER, M_WAITOK | M_ZERO); 857 if (ef->nrelatab != 0) 858 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 859 M_LINKER, M_WAITOK | M_ZERO); 860 861 if (symtabindex == -1) { 862 link_elf_error(filename, "lost symbol table index"); 863 error = ENOEXEC; 864 goto out; 865 } 866 /* Allocate space for and load the symbol table */ 867 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 868 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 869 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab, 870 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 871 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 872 &resid, td); 873 if (error) 874 goto out; 875 if (resid != 0){ 876 error = EINVAL; 877 goto out; 878 } 879 880 /* Allocate space for and load the symbol strings */ 881 ef->ddbstrcnt = shdr[symstrindex].sh_size; 882 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 883 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab, 884 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 885 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 886 &resid, td); 887 if (error) 888 goto out; 889 if (resid != 0){ 890 error = EINVAL; 891 goto out; 892 } 893 894 /* Do we have a string table for the section names? */ 895 shstrindex = -1; 896 if (hdr->e_shstrndx != 0 && 897 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 898 shstrindex = hdr->e_shstrndx; 899 ef->shstrcnt = shdr[shstrindex].sh_size; 900 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 901 M_WAITOK); 902 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab, 903 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 904 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 905 &resid, td); 906 if (error) 907 goto out; 908 if (resid != 0){ 909 error = EINVAL; 910 goto out; 911 } 912 } 913 914 /* Size up code/data(progbits) and bss(nobits). */ 915 alignmask = 0; 916 for (i = 0; i < hdr->e_shnum; i++) { 917 if (shdr[i].sh_size == 0) 918 continue; 919 switch (shdr[i].sh_type) { 920 case SHT_PROGBITS: 921 case SHT_NOBITS: 922 #ifdef __amd64__ 923 case SHT_X86_64_UNWIND: 924 #endif 925 case SHT_INIT_ARRAY: 926 case SHT_FINI_ARRAY: 927 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 928 break; 929 alignmask = shdr[i].sh_addralign - 1; 930 mapsize += alignmask; 931 mapsize &= ~alignmask; 932 mapsize += shdr[i].sh_size; 933 break; 934 } 935 } 936 937 /* 938 * We know how much space we need for the text/data/bss/etc. 939 * This stuff needs to be in a single chunk so that profiling etc 940 * can get the bounds and gdb can associate offsets with modules 941 */ 942 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize), 943 VM_PROT_ALL, 0, thread0.td_ucred); 944 if (ef->object == NULL) { 945 error = ENOMEM; 946 goto out; 947 } 948 #if VM_NRESERVLEVEL > 0 949 vm_object_color(ef->object, 0); 950 #endif 951 952 /* 953 * In order to satisfy amd64's architectural requirements on the 954 * location of code and data in the kernel's address space, request a 955 * mapping that is above the kernel. 956 * 957 * Protections will be restricted once relocations are applied. 958 */ 959 #ifdef __amd64__ 960 mapbase = KERNBASE; 961 #else 962 mapbase = VM_MIN_KERNEL_ADDRESS; 963 #endif 964 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 965 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 966 VM_PROT_ALL, 0); 967 if (error != KERN_SUCCESS) { 968 vm_object_deallocate(ef->object); 969 ef->object = NULL; 970 error = ENOMEM; 971 goto out; 972 } 973 974 /* Wire the pages */ 975 error = vm_map_wire(kernel_map, mapbase, 976 mapbase + round_page(mapsize), 977 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 978 if (error != KERN_SUCCESS) { 979 error = ENOMEM; 980 goto out; 981 } 982 983 /* Inform the kld system about the situation */ 984 lf->address = ef->address = (caddr_t)mapbase; 985 lf->size = mapsize; 986 987 /* 988 * Now load code/data(progbits), zero bss(nobits), allocate space for 989 * and load relocs 990 */ 991 pb = 0; 992 rl = 0; 993 ra = 0; 994 alignmask = 0; 995 for (i = 0; i < hdr->e_shnum; i++) { 996 if (shdr[i].sh_size == 0) 997 continue; 998 switch (shdr[i].sh_type) { 999 case SHT_PROGBITS: 1000 case SHT_NOBITS: 1001 #ifdef __amd64__ 1002 case SHT_X86_64_UNWIND: 1003 #endif 1004 case SHT_INIT_ARRAY: 1005 case SHT_FINI_ARRAY: 1006 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 1007 break; 1008 alignmask = shdr[i].sh_addralign - 1; 1009 mapbase += alignmask; 1010 mapbase &= ~alignmask; 1011 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 1012 ef->progtab[pb].name = 1013 ef->shstrtab + shdr[i].sh_name; 1014 if (!strcmp(ef->progtab[pb].name, ".ctors") || 1015 shdr[i].sh_type == SHT_INIT_ARRAY) { 1016 if (lf->ctors_addr != 0) { 1017 printf( 1018 "%s: multiple ctor sections in %s\n", 1019 __func__, filename); 1020 } else { 1021 lf->ctors_addr = 1022 (caddr_t)mapbase; 1023 lf->ctors_size = 1024 shdr[i].sh_size; 1025 } 1026 } else if (!strcmp(ef->progtab[pb].name, 1027 ".dtors") || 1028 shdr[i].sh_type == SHT_FINI_ARRAY) { 1029 if (lf->dtors_addr != 0) { 1030 printf( 1031 "%s: multiple dtor sections in %s\n", 1032 __func__, filename); 1033 } else { 1034 lf->dtors_addr = 1035 (caddr_t)mapbase; 1036 lf->dtors_size = 1037 shdr[i].sh_size; 1038 } 1039 } 1040 } else if (shdr[i].sh_type == SHT_PROGBITS) 1041 ef->progtab[pb].name = "<<PROGBITS>>"; 1042 #ifdef __amd64__ 1043 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 1044 ef->progtab[pb].name = "<<UNWIND>>"; 1045 #endif 1046 else 1047 ef->progtab[pb].name = "<<NOBITS>>"; 1048 if (ef->progtab[pb].name != NULL && 1049 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 1050 ef->progtab[pb].addr = 1051 dpcpu_alloc(shdr[i].sh_size); 1052 if (ef->progtab[pb].addr == NULL) { 1053 printf("%s: pcpu module space is out " 1054 "of space; cannot allocate %#jx " 1055 "for %s\n", __func__, 1056 (uintmax_t)shdr[i].sh_size, 1057 filename); 1058 } 1059 } 1060 #ifdef VIMAGE 1061 else if (ef->progtab[pb].name != NULL && 1062 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 1063 ef->progtab[pb].addr = 1064 vnet_data_alloc(shdr[i].sh_size); 1065 if (ef->progtab[pb].addr == NULL) { 1066 printf("%s: vnet module space is out " 1067 "of space; cannot allocate %#jx " 1068 "for %s\n", __func__, 1069 (uintmax_t)shdr[i].sh_size, 1070 filename); 1071 } 1072 } 1073 #endif 1074 else 1075 ef->progtab[pb].addr = 1076 (void *)(uintptr_t)mapbase; 1077 if (ef->progtab[pb].addr == NULL) { 1078 error = ENOSPC; 1079 goto out; 1080 } 1081 ef->progtab[pb].size = shdr[i].sh_size; 1082 ef->progtab[pb].flags = shdr[i].sh_flags; 1083 ef->progtab[pb].sec = i; 1084 if (shdr[i].sh_type == SHT_PROGBITS 1085 #ifdef __amd64__ 1086 || shdr[i].sh_type == SHT_X86_64_UNWIND 1087 #endif 1088 ) { 1089 error = vn_rdwr(UIO_READ, nd->ni_vp, 1090 ef->progtab[pb].addr, 1091 shdr[i].sh_size, shdr[i].sh_offset, 1092 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 1093 NOCRED, &resid, td); 1094 if (error) 1095 goto out; 1096 if (resid != 0){ 1097 error = EINVAL; 1098 goto out; 1099 } 1100 /* Initialize the per-cpu or vnet area. */ 1101 if (ef->progtab[pb].addr != (void *)mapbase && 1102 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 1103 dpcpu_copy(ef->progtab[pb].addr, 1104 shdr[i].sh_size); 1105 #ifdef VIMAGE 1106 else if (ef->progtab[pb].addr != 1107 (void *)mapbase && 1108 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 1109 vnet_data_copy(ef->progtab[pb].addr, 1110 shdr[i].sh_size); 1111 #endif 1112 } else 1113 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 1114 1115 /* Update all symbol values with the offset. */ 1116 for (j = 0; j < ef->ddbsymcnt; j++) { 1117 es = &ef->ddbsymtab[j]; 1118 if (es->st_shndx != i) 1119 continue; 1120 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 1121 } 1122 mapbase += shdr[i].sh_size; 1123 pb++; 1124 break; 1125 case SHT_REL: 1126 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1127 break; 1128 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 1129 M_WAITOK); 1130 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 1131 ef->reltab[rl].sec = shdr[i].sh_info; 1132 error = vn_rdwr(UIO_READ, nd->ni_vp, 1133 (void *)ef->reltab[rl].rel, 1134 shdr[i].sh_size, shdr[i].sh_offset, 1135 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1136 &resid, td); 1137 if (error) 1138 goto out; 1139 if (resid != 0){ 1140 error = EINVAL; 1141 goto out; 1142 } 1143 rl++; 1144 break; 1145 case SHT_RELA: 1146 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1147 break; 1148 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 1149 M_WAITOK); 1150 ef->relatab[ra].nrela = 1151 shdr[i].sh_size / sizeof(Elf_Rela); 1152 ef->relatab[ra].sec = shdr[i].sh_info; 1153 error = vn_rdwr(UIO_READ, nd->ni_vp, 1154 (void *)ef->relatab[ra].rela, 1155 shdr[i].sh_size, shdr[i].sh_offset, 1156 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1157 &resid, td); 1158 if (error) 1159 goto out; 1160 if (resid != 0){ 1161 error = EINVAL; 1162 goto out; 1163 } 1164 ra++; 1165 break; 1166 } 1167 } 1168 if (pb != ef->nprogtab) { 1169 link_elf_error(filename, "lost progbits"); 1170 error = ENOEXEC; 1171 goto out; 1172 } 1173 if (rl != ef->nreltab) { 1174 link_elf_error(filename, "lost reltab"); 1175 error = ENOEXEC; 1176 goto out; 1177 } 1178 if (ra != ef->nrelatab) { 1179 link_elf_error(filename, "lost relatab"); 1180 error = ENOEXEC; 1181 goto out; 1182 } 1183 if (mapbase != (vm_offset_t)ef->address + mapsize) { 1184 printf( 1185 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 1186 filename != NULL ? filename : "<none>", 1187 (u_long)mapbase, ef->address, (u_long)mapsize, 1188 (u_long)(vm_offset_t)ef->address + mapsize); 1189 error = ENOMEM; 1190 goto out; 1191 } 1192 1193 /* Local intra-module relocations */ 1194 error = link_elf_reloc_local(lf, false); 1195 if (error != 0) 1196 goto out; 1197 1198 /* Pull in dependencies */ 1199 VOP_UNLOCK(nd->ni_vp); 1200 error = linker_load_dependencies(lf); 1201 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY); 1202 if (error) 1203 goto out; 1204 1205 /* External relocations */ 1206 error = relocate_file(ef); 1207 if (error) 1208 goto out; 1209 1210 /* Notify MD code that a module is being loaded. */ 1211 error = elf_cpu_load_file(lf); 1212 if (error) 1213 goto out; 1214 1215 #if defined(__i386__) || defined(__amd64__) 1216 /* Now ifuncs. */ 1217 error = link_elf_reloc_local(lf, true); 1218 if (error != 0) 1219 goto out; 1220 #endif 1221 1222 link_elf_protect(ef); 1223 link_elf_invoke_cbs(lf->ctors_addr, lf->ctors_size); 1224 *result = lf; 1225 1226 out: 1227 VOP_UNLOCK(nd->ni_vp); 1228 vn_close(nd->ni_vp, FREAD, td->td_ucred, td); 1229 free(nd, M_TEMP); 1230 if (error && lf) 1231 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1232 free(hdr, M_LINKER); 1233 1234 return error; 1235 } 1236 1237 static void 1238 link_elf_unload_file(linker_file_t file) 1239 { 1240 elf_file_t ef = (elf_file_t) file; 1241 u_int i; 1242 1243 link_elf_invoke_cbs(file->dtors_addr, file->dtors_size); 1244 1245 /* Notify MD code that a module is being unloaded. */ 1246 elf_cpu_unload_file(file); 1247 1248 if (ef->progtab) { 1249 for (i = 0; i < ef->nprogtab; i++) { 1250 if (ef->progtab[i].size == 0) 1251 continue; 1252 if (ef->progtab[i].name == NULL) 1253 continue; 1254 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1255 dpcpu_free(ef->progtab[i].addr, 1256 ef->progtab[i].size); 1257 #ifdef VIMAGE 1258 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1259 vnet_data_free(ef->progtab[i].addr, 1260 ef->progtab[i].size); 1261 #endif 1262 } 1263 } 1264 if (ef->preloaded) { 1265 free(ef->reltab, M_LINKER); 1266 free(ef->relatab, M_LINKER); 1267 free(ef->progtab, M_LINKER); 1268 free(ef->ctftab, M_LINKER); 1269 free(ef->ctfoff, M_LINKER); 1270 free(ef->typoff, M_LINKER); 1271 if (file->pathname != NULL) 1272 preload_delete_name(file->pathname); 1273 return; 1274 } 1275 1276 for (i = 0; i < ef->nreltab; i++) 1277 free(ef->reltab[i].rel, M_LINKER); 1278 for (i = 0; i < ef->nrelatab; i++) 1279 free(ef->relatab[i].rela, M_LINKER); 1280 free(ef->reltab, M_LINKER); 1281 free(ef->relatab, M_LINKER); 1282 free(ef->progtab, M_LINKER); 1283 1284 if (ef->object != NULL) 1285 vm_map_remove(kernel_map, (vm_offset_t)ef->address, 1286 (vm_offset_t)ef->address + ptoa(ef->object->size)); 1287 free(ef->e_shdr, M_LINKER); 1288 free(ef->ddbsymtab, M_LINKER); 1289 free(ef->ddbstrtab, M_LINKER); 1290 free(ef->shstrtab, M_LINKER); 1291 free(ef->ctftab, M_LINKER); 1292 free(ef->ctfoff, M_LINKER); 1293 free(ef->typoff, M_LINKER); 1294 } 1295 1296 static const char * 1297 symbol_name(elf_file_t ef, Elf_Size r_info) 1298 { 1299 const Elf_Sym *ref; 1300 1301 if (ELF_R_SYM(r_info)) { 1302 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1303 return ef->ddbstrtab + ref->st_name; 1304 } else 1305 return NULL; 1306 } 1307 1308 static Elf_Addr 1309 findbase(elf_file_t ef, int sec) 1310 { 1311 int i; 1312 Elf_Addr base = 0; 1313 1314 for (i = 0; i < ef->nprogtab; i++) { 1315 if (sec == ef->progtab[i].sec) { 1316 base = (Elf_Addr)ef->progtab[i].addr; 1317 break; 1318 } 1319 } 1320 return base; 1321 } 1322 1323 static int 1324 relocate_file1(elf_file_t ef, bool ifuncs) 1325 { 1326 const Elf_Rel *rellim; 1327 const Elf_Rel *rel; 1328 const Elf_Rela *relalim; 1329 const Elf_Rela *rela; 1330 const char *symname; 1331 const Elf_Sym *sym; 1332 int i; 1333 Elf_Size symidx; 1334 Elf_Addr base; 1335 1336 /* Perform relocations without addend if there are any: */ 1337 for (i = 0; i < ef->nreltab; i++) { 1338 rel = ef->reltab[i].rel; 1339 if (rel == NULL) { 1340 link_elf_error(ef->lf.filename, "lost a reltab!"); 1341 return (ENOEXEC); 1342 } 1343 rellim = rel + ef->reltab[i].nrel; 1344 base = findbase(ef, ef->reltab[i].sec); 1345 if (base == 0) { 1346 link_elf_error(ef->lf.filename, "lost base for reltab"); 1347 return (ENOEXEC); 1348 } 1349 for ( ; rel < rellim; rel++) { 1350 symidx = ELF_R_SYM(rel->r_info); 1351 if (symidx >= ef->ddbsymcnt) 1352 continue; 1353 sym = ef->ddbsymtab + symidx; 1354 /* Local relocs are already done */ 1355 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1356 continue; 1357 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1358 elf_is_ifunc_reloc(rel->r_info)) != ifuncs) 1359 continue; 1360 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1361 elf_obj_lookup)) { 1362 symname = symbol_name(ef, rel->r_info); 1363 printf("link_elf_obj: symbol %s undefined\n", 1364 symname); 1365 return (ENOENT); 1366 } 1367 } 1368 } 1369 1370 /* Perform relocations with addend if there are any: */ 1371 for (i = 0; i < ef->nrelatab; i++) { 1372 rela = ef->relatab[i].rela; 1373 if (rela == NULL) { 1374 link_elf_error(ef->lf.filename, "lost a relatab!"); 1375 return (ENOEXEC); 1376 } 1377 relalim = rela + ef->relatab[i].nrela; 1378 base = findbase(ef, ef->relatab[i].sec); 1379 if (base == 0) { 1380 link_elf_error(ef->lf.filename, 1381 "lost base for relatab"); 1382 return (ENOEXEC); 1383 } 1384 for ( ; rela < relalim; rela++) { 1385 symidx = ELF_R_SYM(rela->r_info); 1386 if (symidx >= ef->ddbsymcnt) 1387 continue; 1388 sym = ef->ddbsymtab + symidx; 1389 /* Local relocs are already done */ 1390 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1391 continue; 1392 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1393 elf_is_ifunc_reloc(rela->r_info)) != ifuncs) 1394 continue; 1395 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1396 elf_obj_lookup)) { 1397 symname = symbol_name(ef, rela->r_info); 1398 printf("link_elf_obj: symbol %s undefined\n", 1399 symname); 1400 return (ENOENT); 1401 } 1402 } 1403 } 1404 1405 /* 1406 * Only clean SHN_FBSD_CACHED for successful return. If we 1407 * modified symbol table for the object but found an 1408 * unresolved symbol, there is no reason to roll back. 1409 */ 1410 elf_obj_cleanup_globals_cache(ef); 1411 1412 return (0); 1413 } 1414 1415 static int 1416 relocate_file(elf_file_t ef) 1417 { 1418 int error; 1419 1420 error = relocate_file1(ef, false); 1421 if (error == 0) 1422 error = relocate_file1(ef, true); 1423 return (error); 1424 } 1425 1426 static int 1427 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1428 { 1429 elf_file_t ef = (elf_file_t) lf; 1430 const Elf_Sym *symp; 1431 const char *strp; 1432 int i; 1433 1434 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1435 strp = ef->ddbstrtab + symp->st_name; 1436 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1437 *sym = (c_linker_sym_t) symp; 1438 return 0; 1439 } 1440 } 1441 return (ENOENT); 1442 } 1443 1444 static int 1445 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1446 linker_symval_t *symval) 1447 { 1448 elf_file_t ef; 1449 const Elf_Sym *es; 1450 caddr_t val; 1451 1452 ef = (elf_file_t) lf; 1453 es = (const Elf_Sym*) sym; 1454 val = (caddr_t)es->st_value; 1455 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1456 symval->name = ef->ddbstrtab + es->st_name; 1457 val = (caddr_t)es->st_value; 1458 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1459 val = ((caddr_t (*)(void))val)(); 1460 symval->value = val; 1461 symval->size = es->st_size; 1462 return (0); 1463 } 1464 return (ENOENT); 1465 } 1466 1467 static int 1468 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1469 c_linker_sym_t *sym, long *diffp) 1470 { 1471 elf_file_t ef = (elf_file_t)lf; 1472 u_long off = (uintptr_t)(void *)value; 1473 u_long diff = off; 1474 u_long st_value; 1475 const Elf_Sym *es; 1476 const Elf_Sym *best = NULL; 1477 int i; 1478 1479 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1480 if (es->st_name == 0) 1481 continue; 1482 st_value = es->st_value; 1483 if (off >= st_value) { 1484 if (off - st_value < diff) { 1485 diff = off - st_value; 1486 best = es; 1487 if (diff == 0) 1488 break; 1489 } else if (off - st_value == diff) { 1490 best = es; 1491 } 1492 } 1493 } 1494 if (best == NULL) 1495 *diffp = off; 1496 else 1497 *diffp = diff; 1498 *sym = (c_linker_sym_t) best; 1499 1500 return (0); 1501 } 1502 1503 /* 1504 * Look up a linker set on an ELF system. 1505 */ 1506 static int 1507 link_elf_lookup_set(linker_file_t lf, const char *name, 1508 void ***startp, void ***stopp, int *countp) 1509 { 1510 elf_file_t ef = (elf_file_t)lf; 1511 void **start, **stop; 1512 int i, count; 1513 1514 /* Relative to section number */ 1515 for (i = 0; i < ef->nprogtab; i++) { 1516 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1517 strcmp(ef->progtab[i].name + 4, name) == 0) { 1518 start = (void **)ef->progtab[i].addr; 1519 stop = (void **)((char *)ef->progtab[i].addr + 1520 ef->progtab[i].size); 1521 count = stop - start; 1522 if (startp) 1523 *startp = start; 1524 if (stopp) 1525 *stopp = stop; 1526 if (countp) 1527 *countp = count; 1528 return (0); 1529 } 1530 } 1531 return (ESRCH); 1532 } 1533 1534 static int 1535 link_elf_each_function_name(linker_file_t file, 1536 int (*callback)(const char *, void *), void *opaque) 1537 { 1538 elf_file_t ef = (elf_file_t)file; 1539 const Elf_Sym *symp; 1540 int i, error; 1541 1542 /* Exhaustive search */ 1543 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1544 if (symp->st_value != 0 && 1545 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1546 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1547 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1548 if (error) 1549 return (error); 1550 } 1551 } 1552 return (0); 1553 } 1554 1555 static int 1556 link_elf_each_function_nameval(linker_file_t file, 1557 linker_function_nameval_callback_t callback, void *opaque) 1558 { 1559 linker_symval_t symval; 1560 elf_file_t ef = (elf_file_t)file; 1561 const Elf_Sym* symp; 1562 int i, error; 1563 1564 /* Exhaustive search */ 1565 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1566 if (symp->st_value != 0 && 1567 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1568 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1569 error = link_elf_symbol_values(file, 1570 (c_linker_sym_t)symp, &symval); 1571 if (error) 1572 return (error); 1573 error = callback(file, i, &symval, opaque); 1574 if (error) 1575 return (error); 1576 } 1577 } 1578 return (0); 1579 } 1580 1581 static void 1582 elf_obj_cleanup_globals_cache(elf_file_t ef) 1583 { 1584 Elf_Sym *sym; 1585 Elf_Size i; 1586 1587 for (i = 0; i < ef->ddbsymcnt; i++) { 1588 sym = ef->ddbsymtab + i; 1589 if (sym->st_shndx == SHN_FBSD_CACHED) { 1590 sym->st_shndx = SHN_UNDEF; 1591 sym->st_value = 0; 1592 } 1593 } 1594 } 1595 1596 /* 1597 * Symbol lookup function that can be used when the symbol index is known (ie 1598 * in relocations). It uses the symbol index instead of doing a fully fledged 1599 * hash table based lookup when such is valid. For example for local symbols. 1600 * This is not only more efficient, it's also more correct. It's not always 1601 * the case that the symbol can be found through the hash table. 1602 */ 1603 static int 1604 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1605 { 1606 elf_file_t ef = (elf_file_t)lf; 1607 Elf_Sym *sym; 1608 const char *symbol; 1609 Elf_Addr res1; 1610 1611 /* Don't even try to lookup the symbol if the index is bogus. */ 1612 if (symidx >= ef->ddbsymcnt) { 1613 *res = 0; 1614 return (EINVAL); 1615 } 1616 1617 sym = ef->ddbsymtab + symidx; 1618 1619 /* Quick answer if there is a definition included. */ 1620 if (sym->st_shndx != SHN_UNDEF) { 1621 res1 = (Elf_Addr)sym->st_value; 1622 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1623 res1 = ((Elf_Addr (*)(void))res1)(); 1624 *res = res1; 1625 return (0); 1626 } 1627 1628 /* If we get here, then it is undefined and needs a lookup. */ 1629 switch (ELF_ST_BIND(sym->st_info)) { 1630 case STB_LOCAL: 1631 /* Local, but undefined? huh? */ 1632 *res = 0; 1633 return (EINVAL); 1634 1635 case STB_GLOBAL: 1636 case STB_WEAK: 1637 /* Relative to Data or Function name */ 1638 symbol = ef->ddbstrtab + sym->st_name; 1639 1640 /* Force a lookup failure if the symbol name is bogus. */ 1641 if (*symbol == 0) { 1642 *res = 0; 1643 return (EINVAL); 1644 } 1645 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1646 1647 /* 1648 * Cache global lookups during module relocation. The failure 1649 * case is particularly expensive for callers, who must scan 1650 * through the entire globals table doing strcmp(). Cache to 1651 * avoid doing such work repeatedly. 1652 * 1653 * After relocation is complete, undefined globals will be 1654 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1655 * above. 1656 */ 1657 if (res1 != 0) { 1658 sym->st_shndx = SHN_FBSD_CACHED; 1659 sym->st_value = res1; 1660 *res = res1; 1661 return (0); 1662 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1663 sym->st_value = 0; 1664 *res = 0; 1665 return (0); 1666 } 1667 return (EINVAL); 1668 1669 default: 1670 return (EINVAL); 1671 } 1672 } 1673 1674 static void 1675 link_elf_fix_link_set(elf_file_t ef) 1676 { 1677 static const char startn[] = "__start_"; 1678 static const char stopn[] = "__stop_"; 1679 Elf_Sym *sym; 1680 const char *sym_name, *linkset_name; 1681 Elf_Addr startp, stopp; 1682 Elf_Size symidx; 1683 int start, i; 1684 1685 startp = stopp = 0; 1686 for (symidx = 1 /* zero entry is special */; 1687 symidx < ef->ddbsymcnt; symidx++) { 1688 sym = ef->ddbsymtab + symidx; 1689 if (sym->st_shndx != SHN_UNDEF) 1690 continue; 1691 1692 sym_name = ef->ddbstrtab + sym->st_name; 1693 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1694 start = 1; 1695 linkset_name = sym_name + sizeof(startn) - 1; 1696 } 1697 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1698 start = 0; 1699 linkset_name = sym_name + sizeof(stopn) - 1; 1700 } 1701 else 1702 continue; 1703 1704 for (i = 0; i < ef->nprogtab; i++) { 1705 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1706 startp = (Elf_Addr)ef->progtab[i].addr; 1707 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1708 break; 1709 } 1710 } 1711 if (i == ef->nprogtab) 1712 continue; 1713 1714 sym->st_value = start ? startp : stopp; 1715 sym->st_shndx = i; 1716 } 1717 } 1718 1719 static int 1720 link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1721 { 1722 elf_file_t ef = (elf_file_t)lf; 1723 const Elf_Rel *rellim; 1724 const Elf_Rel *rel; 1725 const Elf_Rela *relalim; 1726 const Elf_Rela *rela; 1727 const Elf_Sym *sym; 1728 Elf_Addr base; 1729 int i; 1730 Elf_Size symidx; 1731 1732 link_elf_fix_link_set(ef); 1733 1734 /* Perform relocations without addend if there are any: */ 1735 for (i = 0; i < ef->nreltab; i++) { 1736 rel = ef->reltab[i].rel; 1737 if (rel == NULL) { 1738 link_elf_error(ef->lf.filename, "lost a reltab"); 1739 return (ENOEXEC); 1740 } 1741 rellim = rel + ef->reltab[i].nrel; 1742 base = findbase(ef, ef->reltab[i].sec); 1743 if (base == 0) { 1744 link_elf_error(ef->lf.filename, "lost base for reltab"); 1745 return (ENOEXEC); 1746 } 1747 for ( ; rel < rellim; rel++) { 1748 symidx = ELF_R_SYM(rel->r_info); 1749 if (symidx >= ef->ddbsymcnt) 1750 continue; 1751 sym = ef->ddbsymtab + symidx; 1752 /* Only do local relocs */ 1753 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1754 continue; 1755 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1756 elf_is_ifunc_reloc(rel->r_info)) != ifuncs) 1757 continue; 1758 if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1759 elf_obj_lookup) != 0) 1760 return (ENOEXEC); 1761 } 1762 } 1763 1764 /* Perform relocations with addend if there are any: */ 1765 for (i = 0; i < ef->nrelatab; i++) { 1766 rela = ef->relatab[i].rela; 1767 if (rela == NULL) { 1768 link_elf_error(ef->lf.filename, "lost a relatab!"); 1769 return (ENOEXEC); 1770 } 1771 relalim = rela + ef->relatab[i].nrela; 1772 base = findbase(ef, ef->relatab[i].sec); 1773 if (base == 0) { 1774 link_elf_error(ef->lf.filename, "lost base for reltab"); 1775 return (ENOEXEC); 1776 } 1777 for ( ; rela < relalim; rela++) { 1778 symidx = ELF_R_SYM(rela->r_info); 1779 if (symidx >= ef->ddbsymcnt) 1780 continue; 1781 sym = ef->ddbsymtab + symidx; 1782 /* Only do local relocs */ 1783 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1784 continue; 1785 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1786 elf_is_ifunc_reloc(rela->r_info)) != ifuncs) 1787 continue; 1788 if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1789 elf_obj_lookup) != 0) 1790 return (ENOEXEC); 1791 } 1792 } 1793 return (0); 1794 } 1795 1796 static long 1797 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1798 { 1799 elf_file_t ef = (elf_file_t)lf; 1800 1801 *symtab = ef->ddbsymtab; 1802 if (*symtab == NULL) 1803 return (0); 1804 return (ef->ddbsymcnt); 1805 } 1806 1807 static long 1808 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1809 { 1810 elf_file_t ef = (elf_file_t)lf; 1811 1812 *strtab = ef->ddbstrtab; 1813 if (*strtab == NULL) 1814 return (0); 1815 return (ef->ddbstrcnt); 1816 } 1817