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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 | /* * Copyright (c) 2017 Apple Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #include <stdint.h> #include <stdio.h> #include <string.h> #include <assert.h> #include <errno.h> #include <mach/machine.h> #include <mach-o/fat.h> #include <uuid/uuid.h> #include <TargetConditionals.h> #if !TARGET_OS_EXCLAVEKIT #include <mach-o/reloc.h> #include <libc_private.h> #endif // !TARGET_OS_EXCLAVEKIT #include "Image.h" #include "Misc.h" #include "CompactUnwind.h" namespace mach_o { Image::Image(const void* buffer, size_t bufferSize, MappingKind kind) : _buffer((Header*)buffer), _bufferSize(bufferSize), _hasZerofillExpansion(false) { // figure out location of LINKEDIT switch ( kind ) { case MappingKind::wholeSliceMapped: _hasZerofillExpansion = false; break; case MappingKind::dyldLoadedPreFixups: case MappingKind::dyldLoadedPostFixups: _hasZerofillExpansion = _buffer->hasZerofillExpansion(); break; case MappingKind::unknown: _hasZerofillExpansion = inferIfZerofillExpanded(); break; } _linkeditBias = _buffer->computeLinkEditBias(_hasZerofillExpansion); // minimal check of load commands if ( Error err = _buffer->validStructureLoadCommands(bufferSize) ) return; // build parts makeExportsTrie(); makeSymbolTable(); makeRebaseOpcodes(); makeBindOpcodes(); makeLazyBindOpcodes(); makeWeakBindOpcodes(); makeChainedFixups(); makeFunctionStarts(); makeCompactUnwind(); makeSplitSegInfo(); } // need move constructor because object has pointers to within itself (e.g. _exportsTrie points to _exportsTrieSpace) Image::Image(const Image&& other) : _buffer(other._buffer), _bufferSize(other._bufferSize), _linkeditBias(other._linkeditBias), _hasZerofillExpansion(other._hasZerofillExpansion) { // build parts makeExportsTrie(); makeSymbolTable(); makeRebaseOpcodes(); makeBindOpcodes(); makeLazyBindOpcodes(); makeWeakBindOpcodes(); makeChainedFixups(); makeFunctionStarts(); makeCompactUnwind(); makeSplitSegInfo(); } // used to figure out of mach-o was mapped with zero fill or not bool Image::inferIfZerofillExpanded() const { // MH_PRELOAD files can only be wholeSliceMapped because load commands and linkedit are not in segments if ( _buffer->isPreload() || _buffer->isFileSet() ) return false; // if file has no zero-fill, then both ways to load are the same if ( !_buffer->hasZerofillExpansion() ) return false; // if file is code-signed, check for code-sig-magic in both possible locations { uint32_t sigFileOffset; uint32_t sigSize; if ( _buffer->hasCodeSignature(sigFileOffset, sigSize) ) { if ( sigFileOffset < _bufferSize ) { const uint32_t* unexpandedLoc = (uint32_t*)((uint8_t*)_buffer + sigFileOffset); if ( *unexpandedLoc == 0xc00cdefa ) // CSMAGIC_EMBEDDED_SIGNATURE return false; const uint32_t* expandedLoc = (uint32_t*)((uint8_t*)_buffer + _buffer->zerofillExpansionAmount() + sigFileOffset); if ( *expandedLoc == 0xc00cdefa ) return true; } } } // FIXME: assert(false && "handle unsigned"); return false; } Error Image::validate() const { // validate mach_header and load commands if ( Error err = _buffer->valid(_bufferSize) ) return err; // create Policy object for this binary Policy policy(_buffer->arch(), _buffer->platformAndVersions(), _buffer->mh.filetype, false); // validate LINKEDIT if ( Error err = this->validLinkedit(policy) ) return err; return Error::none(); } Error Image::validLinkedit(const Policy& policy) const { // validate structure of linkedit if ( Error err = validStructureLinkedit(policy) ) return err; // if image has an exports trie, validate that if ( this->hasExportsTrie() ) { uint64_t max = 0x200000000; // FIXME if ( Error err = this->exportsTrie().valid(max) ) return err; } // if image has a symbol table, validate that if ( this->hasSymbolTable() ) { uint64_t max = 0x200000000; // FIXME if ( Error err = this->symbolTable().valid(max) ) return err; } uint32_t segCount = this->segmentCount(); MappedSegment segs[segCount]; for (uint32_t i=0; i < segCount; ++i) segs[i] = this->segment(i); std::span<const MappedSegment> segSpan{segs, segCount}; // if image has rebase opcodes if ( this->hasRebaseOpcodes() ) { if ( Error err = this->rebaseOpcodes().valid(segSpan, _buffer->mayHaveTextFixups(), policy.enforceFixupsInWritableSegments()) ) return err; } // if image has bind opcodes if ( this->hasBindOpcodes() ) { if ( Error err = this->bindOpcodes().valid(segSpan, _buffer->dependentDylibCount(), _buffer->mayHaveTextFixups(), policy.enforceFixupsInWritableSegments()) ) return err; } // if image has lazy bind opcodes if ( this->hasLazyBindOpcodes() ) { if ( Error err = this->lazyBindOpcodes().valid(segSpan, _buffer->dependentDylibCount(), _buffer->mayHaveTextFixups(), policy.enforceFixupsInWritableSegments()) ) return err; } // if image has chained fixups if ( this->hasChainedFixups() ) { if ( Error err = this->chainedFixups().valid(segSpan) ) return err; } return Error::none(); } namespace { struct LinkEditContentChunk { const char* name; uint32_t alignment; uint32_t fileOffset; size_t size; // only have a few chunks, so bubble sort is ok. Don't use libc's qsort because it may call malloc static void sort(LinkEditContentChunk array[], unsigned long count) { for ( unsigned i = 0; i < count - 1; ++i ) { bool done = true; for ( unsigned j = 0; j < count - i - 1; ++j ) { if ( array[j].fileOffset > array[j + 1].fileOffset ) { LinkEditContentChunk temp = array[j]; array[j] = array[j + 1]; array[j + 1] = temp; done = false; } } if ( done ) break; } } }; } // anonymous namespace #if !TARGET_OS_EXCLAVEKIT Error Image::validStructureLinkedit(const Policy& policy) const { // build vector of all blobs in LINKEDIT const uint32_t ptrSize = _buffer->pointerSize(); LinkEditContentChunk blobs[32]; __block LinkEditContentChunk* bp = blobs; __block uint32_t symCount = 0; __block uint32_t indSymCount = 0; __block bool hasIndSymTab = false; __block bool hasLocalRelocs = false; __block bool hasExternalRelocs = false; __block bool hasDyldInfo = false; __block bool hasChainedFixups = false; __block Error lcError; (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { switch ( cmd->cmd ) { case LC_SYMTAB: { const symtab_command* symbTabCmd = (symtab_command*)cmd; symCount = symbTabCmd->nsyms; if ( symCount != 0 ) { if ( symCount > 0x10000000 ) { lcError = Error("malformed mach-o image: symbol table too large"); stop = true; } size_t size = symCount * (ptrSize == 8 ? sizeof(nlist_64) : sizeof(struct nlist)); *bp++ = { "symbol table", ptrSize, symbTabCmd->symoff, (uint32_t)size }; } if ( symbTabCmd->strsize != 0 ) *bp++ = { "symbol table strings", 1, symbTabCmd->stroff, symbTabCmd->strsize }; } break; case LC_DYSYMTAB: { hasIndSymTab = true; const dysymtab_command* dySymTabCmd = (dysymtab_command*)cmd; if ( dySymTabCmd->nindirectsyms > 0x10000000 ) { lcError = Error("malformed mach-o image: indirect symbol table too large"); stop = true; } else if ( dySymTabCmd->ilocalsym != 0 ) { lcError = Error("malformed mach-o image: indirect symbol table ilocalsym != 0"); stop = true; } else if ( dySymTabCmd->iextdefsym != dySymTabCmd->nlocalsym ) { lcError = Error("malformed mach-o image: indirect symbol table iextdefsym != nlocalsym"); stop = true; } else if ( dySymTabCmd->iundefsym != (dySymTabCmd->iextdefsym + dySymTabCmd->nextdefsym) ) { lcError = Error("malformed mach-o image: indirect symbol table iundefsym != iextdefsym+nextdefsym"); stop = true; } indSymCount = dySymTabCmd->iundefsym + dySymTabCmd->nundefsym; if ( dySymTabCmd->nlocrel != 0 ) { hasLocalRelocs = true; *bp++ = { "local relocations", ptrSize, dySymTabCmd->locreloff, dySymTabCmd->nlocrel * sizeof(relocation_info) }; } if ( dySymTabCmd->nextrel != 0 ) { hasExternalRelocs = true; *bp++ = { "external relocations", ptrSize, dySymTabCmd->extreloff, dySymTabCmd->nextrel * sizeof(relocation_info) }; } if ( dySymTabCmd->nindirectsyms != 0 ) *bp++ = { "indirect symbol table", 4, dySymTabCmd->indirectsymoff, dySymTabCmd->nindirectsyms * 4 }; } break; case LC_DYLD_INFO_ONLY: hasDyldInfo = true; [[clang::fallthrough]]; case LC_DYLD_INFO: { const dyld_info_command* dyldInfoCmd = (dyld_info_command*)cmd; if ( dyldInfoCmd->rebase_size != 0 ) *bp++ = { "rebase opcodes", ptrSize, dyldInfoCmd->rebase_off, dyldInfoCmd->rebase_size }; if ( dyldInfoCmd->bind_size != 0 ) *bp++ = { "bind opcodes", ptrSize, dyldInfoCmd->bind_off, dyldInfoCmd->bind_size }; if ( dyldInfoCmd->weak_bind_size != 0 ) *bp++ = { "weak bind opcodes", ptrSize, dyldInfoCmd->weak_bind_off, dyldInfoCmd->weak_bind_size }; if ( dyldInfoCmd->lazy_bind_size != 0 ) *bp++ = { "lazy bind opcodes", ptrSize, dyldInfoCmd->lazy_bind_off, dyldInfoCmd->lazy_bind_size }; if ( dyldInfoCmd->export_size != 0 ) *bp++ = { "exports trie", ptrSize, dyldInfoCmd->export_off, dyldInfoCmd->export_size }; } break; case LC_SEGMENT_SPLIT_INFO: { const linkedit_data_command* splitSegCmd = (linkedit_data_command*)cmd; if ( splitSegCmd->datasize != 0 ) *bp++ = { "shared cache info", ptrSize, splitSegCmd->dataoff, splitSegCmd->datasize }; } break; case LC_ATOM_INFO: { const linkedit_data_command* relinkCmd = (linkedit_data_command*)cmd; if ( relinkCmd->datasize != 0 ) *bp++ = { "atom info", ptrSize, relinkCmd->dataoff, relinkCmd->datasize }; } break; case LC_FUNCTION_STARTS: { const linkedit_data_command* funStartsCmd = (linkedit_data_command*)cmd; if ( funStartsCmd->datasize != 0 ) *bp++ = { "function starts", ptrSize, funStartsCmd->dataoff, funStartsCmd->datasize }; } break; case LC_DATA_IN_CODE: { const linkedit_data_command* dataInCodeCmd = (linkedit_data_command*)cmd; if ( dataInCodeCmd->datasize != 0 ) *bp++ = { "data in code", ptrSize, dataInCodeCmd->dataoff, dataInCodeCmd->datasize }; } break; case LC_CODE_SIGNATURE: { const linkedit_data_command* codeSigCmd = (linkedit_data_command*)cmd; if ( codeSigCmd->datasize != 0 ) *bp++ = { "code signature", ptrSize, codeSigCmd->dataoff, codeSigCmd->datasize }; } break; case LC_DYLD_EXPORTS_TRIE: { const linkedit_data_command* exportsTrieCmd = (linkedit_data_command*)cmd; if ( exportsTrieCmd->datasize != 0 ) *bp++ = { "exports trie", ptrSize, exportsTrieCmd->dataoff, exportsTrieCmd->datasize }; } break; case LC_DYLD_CHAINED_FIXUPS: { const linkedit_data_command* chainedFixupsCmd = (linkedit_data_command*)cmd; hasChainedFixups = true; if ( chainedFixupsCmd->datasize != 0 ) *bp++ = { "chained fixups", ptrSize, chainedFixupsCmd->dataoff, chainedFixupsCmd->datasize }; } break; } }); if ( lcError ) return std::move(lcError); if ( hasIndSymTab && (symCount != indSymCount)) return Error("symbol count from symbol table and dynamic symbol table differ"); // check for bad combinations if ( hasDyldInfo && policy.enforceOneFixupEncoding() ) { if ( hasLocalRelocs ) return Error("malformed mach-o contains LC_DYLD_INFO_ONLY and local relocations"); if ( hasExternalRelocs ) return Error("malformed mach-o contains LC_DYLD_INFO_ONLY and external relocations"); } if ( hasChainedFixups ) { if ( hasLocalRelocs ) return Error("malformed mach-o contains LC_DYLD_CHAINED_FIXUPS and local relocations"); if ( hasExternalRelocs ) return Error("malformed mach-o contains LC_DYLD_CHAINED_FIXUPS and external relocations"); } if ( hasDyldInfo && hasChainedFixups ) return Error("malformed mach-o contains LC_DYLD_INFO and LC_DYLD_CHAINED_FIXUPS"); if ( !hasExternalRelocs && !hasLocalRelocs && !hasDyldInfo && !hasChainedFixups && (!_buffer->isMainExecutable() || _buffer->isPIE()) && !_buffer->isObjectFile() ) return Error("malformed mach-o missing relocations, LC_DYLD_INFO, or LC_DYLD_CHAINED_FIXUPS"); // find range of LINKEDIT __block uint64_t linkeditFileOffsetStart = 0; __block uint64_t linkeditFileOffsetEnd = 0; if ( _buffer->isObjectFile() ) { // .o file don't have LINKEDIT, but the LINKEDIT content is still at the end of the file after the last section content _buffer->forEachSection(^(const Header::SectionInfo& info, bool& stop) { uint8_t sectType = (info.flags & SECTION_TYPE); bool isZeroFill = ((sectType == S_ZEROFILL) || (sectType == S_THREAD_LOCAL_ZEROFILL)); if ( isZeroFill ) return; uint64_t sectionEnd = info.fileOffset + info.size; if ( sectionEnd > linkeditFileOffsetStart ) linkeditFileOffsetStart = sectionEnd; }); linkeditFileOffsetEnd = _bufferSize; if ( linkeditFileOffsetStart == 0 ) { // if all sections are zerofill sections, look for symbol table as start of linkedit _buffer->forEachLoadCommandSafe(^(const load_command* cmd, bool& stop) { if ( cmd->cmd == LC_SYMTAB ) { const symtab_command* symTab = (symtab_command*)cmd; linkeditFileOffsetStart = symTab->symoff; } }); } } else { (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( cmd->cmd == LC_SEGMENT_64 ) { const segment_command_64* segCmd = (segment_command_64*)cmd; if ( strcmp(segCmd->segname, "__LINKEDIT") == 0 ) { linkeditFileOffsetStart = segCmd->fileoff; linkeditFileOffsetEnd = segCmd->fileoff + segCmd->filesize; stop = true; } } else if ( cmd->cmd == LC_SEGMENT ) { const segment_command* segCmd = (segment_command*)cmd; if ( strcmp(segCmd->segname, "__LINKEDIT") == 0 ) { linkeditFileOffsetStart = segCmd->fileoff; linkeditFileOffsetEnd = segCmd->fileoff + segCmd->filesize; stop = true; } } }); if ( (linkeditFileOffsetStart == 0) || (linkeditFileOffsetEnd == 0) ) return Error("bad or unknown fileoffset/size for LINKEDIT"); } // sort blobs by file-offset and check for overlaps const unsigned long blobCount = bp - blobs; if ( blobCount == 0 ) { // ok for .o files to have no content and no symbols if ( _buffer->isObjectFile() ) return Error::none(); return Error("malformed mach-o has no LINKEDIT information"); } LinkEditContentChunk::sort(blobs, blobCount); uint64_t prevEnd = linkeditFileOffsetStart; const char* prevName = "start of LINKEDIT"; for ( unsigned long i = 0; i < blobCount; ++i ) { const LinkEditContentChunk& blob = blobs[i]; if ( blob.fileOffset < prevEnd ) { return Error("LINKEDIT overlap of %s and %s", prevName, blob.name); } if ( greaterThanAddOrOverflow((uint64_t)blob.fileOffset, blob.size, linkeditFileOffsetEnd) ) { return Error("LINKEDIT content '%s' extends beyond end of segment", blob.name); } if ( (blob.fileOffset & (blob.alignment - 1)) != 0 ) { // <rdar://problem/51115705> relax code sig alignment for pre iOS 13 if ( strcmp(blob.name, "code signature") == 0 ) { if ( policy.enforceCodeSignatureAligned() ) return Error("mis-aligned code signature"); } else { if ( policy.enforceLinkeditContentAlignment() ) return Error("mis-aligned LINKEDIT content '%s'", blob.name); } } prevEnd = blob.fileOffset + blob.size; prevName = blob.name; } return Error::none(); } void Image::makeExportsTrie() { // if image has an exports trie, use placement new to build ExportTrie object in _exportsTrieSpace (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( cmd->cmd == LC_DYLD_EXPORTS_TRIE ) { const linkedit_data_command* exportsTrie = (linkedit_data_command*)cmd; if ( exportsTrie->dataoff != 0 ) _exportsTrie = new (_exportsTrieSpace) ExportsTrie(_linkeditBias + exportsTrie->dataoff, exportsTrie->datasize); } else if ( (cmd->cmd == LC_DYLD_INFO) || (cmd->cmd == LC_DYLD_INFO_ONLY) ) { const dyld_info_command* dyldInfo = (dyld_info_command*)cmd; if ( dyldInfo->export_off != 0 ) _exportsTrie = new (_exportsTrieSpace) ExportsTrie(_linkeditBias + dyldInfo->export_off, dyldInfo->export_size); } }); } void Image::makeSymbolTable() { // if image has an nlist symbol table, use placement new to build SymbolTable object in _symbolTableSpace __block const symtab_command* symTabCmd = nullptr; __block const dysymtab_command* dynSymTabCmd = nullptr; (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( cmd->cmd == LC_SYMTAB ) { symTabCmd = (symtab_command*)cmd; } else if ( cmd->cmd == LC_DYSYMTAB ) { dynSymTabCmd = (dysymtab_command*)cmd; } }); if ( symTabCmd == nullptr ) return; uint32_t nlocalsym = 0; uint32_t nextdefsym = 0; uint32_t nundefsym = 0; if ( dynSymTabCmd != nullptr ) { // some .o files do not have LC_DYSYMTAB nlocalsym = dynSymTabCmd->nlocalsym; nextdefsym = dynSymTabCmd->nextdefsym; nundefsym = dynSymTabCmd->nundefsym; } if ( _buffer->is64() ) { uint64_t preferredLoadAddress = _buffer->preferredLoadAddress(); const struct nlist_64* nlistArray = (struct nlist_64*)(_linkeditBias + symTabCmd->symoff); _symbolTable = new (_symbolTableSpace) NListSymbolTable(preferredLoadAddress, nlistArray, symTabCmd->nsyms, (char*)_linkeditBias + symTabCmd->stroff, symTabCmd->strsize, nlocalsym, nextdefsym, nundefsym); } else { uint32_t preferredLoadAddress = (uint32_t)_buffer->preferredLoadAddress(); const struct nlist* nlistArray = (struct nlist*)(_linkeditBias + symTabCmd->symoff); _symbolTable = new (_symbolTableSpace) NListSymbolTable(preferredLoadAddress, nlistArray, symTabCmd->nsyms, (char*)_linkeditBias + symTabCmd->stroff, symTabCmd->strsize, nlocalsym, nextdefsym, nundefsym); } } void Image::makeRebaseOpcodes() { // if image has an rebase opcpdes, use placement new to build RebaseOpcodes object in _rebaseOpcodesSpace (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( (cmd->cmd == LC_DYLD_INFO) || (cmd->cmd == LC_DYLD_INFO_ONLY) ) { const dyld_info_command* dyldInfoCmd = (dyld_info_command*)cmd; if ( dyldInfoCmd->rebase_size != 0 ) _rebaseOpcodes = new (_rebaseOpcodesSpace) RebaseOpcodes(_linkeditBias + dyldInfoCmd->rebase_off, dyldInfoCmd->rebase_size, _buffer->is64()); } }); } void Image::makeBindOpcodes() { // if image has an rebase opcpdes, use placement new to build BindOpcodes object in _bindOpcodesSpace (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( (cmd->cmd == LC_DYLD_INFO) || (cmd->cmd == LC_DYLD_INFO_ONLY) ) { const dyld_info_command* dyldInfoCmd = (dyld_info_command*)cmd; if ( dyldInfoCmd->bind_size != 0 ) _bindOpcodes = new (_bindOpcodesSpace) BindOpcodes(_linkeditBias + dyldInfoCmd->bind_off, dyldInfoCmd->bind_size, _buffer->is64()); } }); } void Image::makeLazyBindOpcodes() { // if image has an rebase opcpdes, use placement new to build LazyBindOpcodes object in _lazyBindOpcodesSpace (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( (cmd->cmd == LC_DYLD_INFO) || (cmd->cmd == LC_DYLD_INFO_ONLY) ) { const dyld_info_command* dyldInfoCmd = (dyld_info_command*)cmd; if ( dyldInfoCmd->lazy_bind_size != 0 ) _lazyBindOpcodes = new (_lazyBindOpcodesSpace) LazyBindOpcodes(_linkeditBias + dyldInfoCmd->lazy_bind_off, dyldInfoCmd->lazy_bind_size, _buffer->is64()); } }); } void Image::makeWeakBindOpcodes() { // if image has an rebase opcpdes, use placement new to build BindOpcodes object in _weakBindOpcodesSpace (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( (cmd->cmd == LC_DYLD_INFO) || (cmd->cmd == LC_DYLD_INFO_ONLY) ) { const dyld_info_command* dyldInfoCmd = (dyld_info_command*)cmd; if ( dyldInfoCmd->weak_bind_size != 0 ) _weakBindOpcodes = new (_weakBindOpcodesSpace) BindOpcodes(_linkeditBias + dyldInfoCmd->weak_bind_off, dyldInfoCmd->weak_bind_size, _buffer->is64()); } }); } void Image::makeChainedFixups() { // if image has an fixup chains, use placement new to build ChainedFixups object in _chainedFixupsSpace (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( cmd->cmd == LC_DYLD_CHAINED_FIXUPS ) { const linkedit_data_command* chainedFixupsCmd = (linkedit_data_command*)cmd; if ( chainedFixupsCmd->datasize != 0 ) { const dyld_chained_fixups_header* fixupsHeader = (dyld_chained_fixups_header*)(_linkeditBias + chainedFixupsCmd->dataoff); _chainedFixups = new (_chainedFixupsSpace) ChainedFixups(fixupsHeader, chainedFixupsCmd->datasize); } } }); } void Image::makeFunctionStarts() { // if image has an function starts, use placement new to build FunctionStarts object in _functionStartsSpace (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( cmd->cmd == LC_FUNCTION_STARTS ) { const linkedit_data_command* funcStartsCmd = (linkedit_data_command*)cmd; if ( funcStartsCmd->datasize != 0 ) { const uint8_t* functionsStartBytes = (uint8_t*)(_linkeditBias + funcStartsCmd->dataoff); _functionStarts = new (_functionStartsSpace) FunctionStarts(functionsStartBytes, funcStartsCmd->datasize); } } }); } void Image::makeCompactUnwind() { // if image has an a compact unwind section, use placement new to build CompactUnwind object in _compactUnwindSpace _buffer->forEachSection(^(const Header::SectionInfo& info, bool& stop) { if ( (info.sectionName == "__unwind_info") && info.segmentName.starts_with("__TEXT") ) { const uint8_t* sectionContent = (uint8_t*)_buffer + info.fileOffset; _compactUnwind = new (_compactUnwindSpace) CompactUnwind(_buffer->arch(), sectionContent, (size_t)info.size); stop = true; } }); } void Image::makeSplitSegInfo() { // if image has a split seg info load command, use placement new to build SplitSegInfo object in _splitSegInfoSpace (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( cmd->cmd == LC_SEGMENT_SPLIT_INFO ) { const linkedit_data_command* splitSegCmd = (linkedit_data_command*)cmd; if ( splitSegCmd->datasize != 0 ) { const uint8_t* startBytes = (uint8_t*)(_linkeditBias + splitSegCmd->dataoff); _splitSegInfo = new (_splitSegSpace) SplitSegInfo(startBytes, splitSegCmd->datasize); stop = true; } } }); } uint32_t Image::segmentCount() const { __block uint32_t count = 0; (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( (cmd->cmd == LC_SEGMENT) || (cmd->cmd == LC_SEGMENT_64) ) ++count; }); return count; } MappedSegment Image::segment(uint32_t segIndex) const { __block MappedSegment result; __block uint32_t curSegIndex = 0; __block uint64_t textVmAddr = 0; (void)_buffer->forEachLoadCommand(^(const load_command* cmd, bool& stop) { if ( cmd->cmd == LC_SEGMENT_64 ) { const segment_command_64* segCmd = (segment_command_64*)cmd; if ( strcmp(segCmd->segname, "__TEXT") == 0 ) textVmAddr = segCmd->vmaddr; if ( curSegIndex == segIndex ) { result.runtimeOffset = segCmd->vmaddr - textVmAddr; if ( _hasZerofillExpansion ) result.content = (uint8_t*)_buffer + (segCmd->vmaddr - textVmAddr); else result.content = (uint8_t*)_buffer + segCmd->fileoff; result.runtimeSize = segCmd->vmsize; result.segName = segCmd->segname; result.readable = ((segCmd->initprot & VM_PROT_READ) != 0); result.writable = ((segCmd->initprot & VM_PROT_WRITE) != 0); result.executable = ((segCmd->initprot & VM_PROT_EXECUTE) != 0); stop = true; } ++curSegIndex; } else if ( cmd->cmd == LC_SEGMENT ) { const segment_command* segCmd = (segment_command*)cmd; if ( strcmp(segCmd->segname, "__TEXT") == 0 ) textVmAddr = segCmd->vmaddr; if ( curSegIndex == segIndex ) { result.runtimeOffset = segCmd->vmaddr - textVmAddr; if ( _hasZerofillExpansion ) result.content = (uint8_t*)_buffer + (segCmd->vmaddr - textVmAddr); else result.content = (uint8_t*)_buffer + segCmd->fileoff; result.runtimeSize = segCmd->vmsize; result.segName = segCmd->segname; result.readable = ((segCmd->initprot & VM_PROT_READ) != 0); result.writable = ((segCmd->initprot & VM_PROT_WRITE) != 0); result.executable = ((segCmd->initprot & VM_PROT_EXECUTE) != 0); stop = true; } ++curSegIndex; } }); return result; } #endif // !TARGET_OS_EXCLAVEKIT void Image::withSegments(void (^callback)(std::span<const MappedSegment> segments)) const { const uint32_t count = segmentCount(); MappedSegment segments[count]; for (uint32_t segIndex=0; segIndex < count; ++segIndex) segments[segIndex] = this->segment(segIndex); callback(std::span(segments, count)); } // This is a high level abstraction for mach-o files. No matter the format, it returns all bind targets void Image::forEachBindTarget(void (^callback)(const Fixup::BindTarget& targetInfo, bool& stop)) const { if ( this->hasChainedFixups() ) { this->chainedFixups().forEachBindTarget(callback); } else if ( this->hasBindOpcodes() ) { // FIXME: Do we want to pass up the strong binds? this->bindOpcodes().forEachBindTarget(callback, ^(const char* symbolName) { }); // FIXME: lazy binds } } // This is a high level abstraction for mach-o files. No matter the format, it iterates all fixups void Image::forEachFixup(void (^callback)(const Fixup& fixup, bool& stop)) const { const uint64_t prefLoadAddr = this->header()->preferredLoadAddress(); this->withSegments(^(std::span<const MappedSegment> segments) { if ( this->hasChainedFixups() ) { this->chainedFixups().forEachFixupChainStartLocation(segments, ^(const void* chainStart, uint32_t segIndex, const ChainedFixups::PointerFormat& pf, bool& stop) { pf.forEachFixupLocationInChain(chainStart, prefLoadAddr, &segments[segIndex], callback); }); } else { if ( this->hasBindOpcodes() ) { this->bindOpcodes().forEachBindLocation(segments, callback); } if ( this->hasLazyBindOpcodes() ) { this->lazyBindOpcodes().forEachBindLocation(segments, callback); } if ( this->hasRebaseOpcodes() ) { this->rebaseOpcodes().forEachRebaseLocation(segments, prefLoadAddr, callback); } } }); } std::span<const uint32_t> Image::indirectSymbolTable() const { uint32_t fileOffset; uint32_t count; if ( header()->hasIndirectSymbolTable(fileOffset, count) ) { return std::span<const uint32_t>((uint32_t*)(_linkeditBias + fileOffset), count); } return std::span<const uint32_t>(); } std::span<uint8_t> Image::atomInfo() const { uint32_t fileOffset; uint32_t count; if ( header()->hasAtomInfo(fileOffset, count) ) { return std::span<uint8_t>((uint8_t*)(_linkeditBias + fileOffset), count); } return std::span<uint8_t>(); } } // namespace mach_o |