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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 | /* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- * * Copyright (c) 2015 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 <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <limits.h> #include <stdarg.h> #include <stdio.h> #include <unistd.h> #include <CommonCrypto/CommonDigest.h> #include <string> #include <unordered_map> #include <unordered_set> #include "StringUtils.h" #include "Trie.hpp" #include "MachOFileAbstraction.hpp" #include "MachOAnalyzer.h" #include "Diagnostics.h" #include "DyldSharedCache.h" #include "CacheBuilder.h" static const bool verbose = false; template <typename P> class StubOptimizer { public: StubOptimizer(int64_t cacheSlide, uint64_t cacheUnslidAddr, const std::string& archName, macho_header<P>* mh, const char* dylibID, Diagnostics& diags); void buildStubMap(const std::unordered_set<std::string>& neverStubEliminate); void optimizeStubs(); void optimizeCallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr); const char* dylibID() { return _dylibID; } const uint8_t* exportsTrie() { if ( _dyldInfo != nullptr ) return &_linkeditBias[_dyldInfo->export_off()]; else return &_linkeditBias[_exportTrie->dataoff()]; } uint32_t exportsTrieSize() { if ( _dyldInfo != nullptr ) return _dyldInfo->export_size(); else return _exportTrie->datasize(); } uint32_t _stubCount = 0; uint32_t _stubOptimizedCount = 0; uint32_t _stubsLeftInterposable = 0; uint32_t _branchToStubCount = 0; uint32_t _branchOptimizedToDirectCount = 0; uint32_t _branchToOptimizedStubCount = 0; uint32_t _branchToReUsedOptimizedStubCount = 0; private: typedef std::function<bool(uint8_t callSiteKind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction)> CallSiteHandler; typedef typename P::uint_t pint_t; typedef typename P::E E; void forEachCallSiteToAStub(CallSiteHandler); void optimizeArm64CallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr); void optimizeArm64Stubs(); #if SUPPORT_ARCH_arm64e void optimizeArm64eStubs(); #endif #if SUPPORT_ARCH_arm64_32 void optimizeArm64_32Stubs(); #endif void optimizeArmCallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr); void optimizeArmStubs(); uint64_t lazyPointerAddrFromArm64Stub(const uint8_t* stubInstructions, uint64_t stubVMAddr); #if SUPPORT_ARCH_arm64e uint64_t lazyPointerAddrFromArm64eStub(const uint8_t* stubInstructions, uint64_t stubVMAddr); #endif #if SUPPORT_ARCH_arm64_32 uint64_t lazyPointerAddrFromArm64_32Stub(const uint8_t* stubInstructions, uint64_t stubVMAddr); #endif uint32_t lazyPointerAddrFromArmStub(const uint8_t* stubInstructions, uint32_t stubVMAddr); int32_t getDisplacementFromThumbBranch(uint32_t instruction, uint32_t instrAddr); uint32_t setDisplacementInThumbBranch(uint32_t instruction, uint32_t instrAddr, int32_t displacement, bool targetIsThumb); uint32_t cpuSubtype() { return ((dyld3::MachOFile*)_mh)->maskedCpuSubtype(); } struct AddressAndName { pint_t targetVMAddr; const char* targetName; }; typedef std::unordered_map<pint_t, AddressAndName> StubVMAddrToTarget; static const int64_t b128MegLimit = 0x07FFFFFF; static const int64_t b16MegLimit = 0x00FFFFFF; Diagnostics& _diagnostics; macho_header<P>* _mh; int64_t _cacheSlide = 0; uint64_t _cacheUnslideAddr = 0; uint32_t _linkeditSize = 0; uint64_t _linkeditAddr = 0; const uint8_t* _linkeditBias = nullptr; const char* _dylibID = nullptr; const macho_symtab_command<P>* _symTabCmd = nullptr; const macho_dysymtab_command<P>* _dynSymTabCmd = nullptr; const macho_dyld_info_command<P>* _dyldInfo = nullptr; const macho_linkedit_data_command<P>* _exportTrie = nullptr; macho_linkedit_data_command<P>* _splitSegInfoCmd = nullptr; const macho_section<P>* _textSection = nullptr; const macho_section<P>* _stubSection = nullptr; uint32_t _textSectionIndex = 0; uint32_t _stubSectionIndex = 0; pint_t _textSegStartAddr = 0; std::vector<macho_segment_command<P>*> _segCmds; std::unordered_map<pint_t, pint_t> _stubAddrToLPAddr; std::unordered_map<pint_t, pint_t> _lpAddrToTargetAddr; std::unordered_map<pint_t, const char*> _targetAddrToName; std::unordered_set<uint64_t> _stubsToOptimize; }; template <typename P> StubOptimizer<P>::StubOptimizer(int64_t cacheSlide, uint64_t cacheUnslidAddr, const std::string& archName, macho_header<P>* mh, const char* dylibID, Diagnostics& diags) : _diagnostics(diags), _mh(mh), _cacheSlide(cacheSlide), _cacheUnslideAddr(cacheUnslidAddr), _dylibID(dylibID) { const macho_load_command<P>* const cmds = (macho_load_command<P>*)((uint8_t*)mh + sizeof(macho_header<P>)); const uint32_t cmd_count = mh->ncmds(); macho_segment_command<P>* segCmd; uint32_t sectionIndex = 0; const macho_load_command<P>* cmd = cmds; for (uint32_t i = 0; i < cmd_count; ++i) { switch (cmd->cmd()) { case LC_SYMTAB: _symTabCmd = (macho_symtab_command<P>*)cmd; break; case LC_DYSYMTAB: _dynSymTabCmd = (macho_dysymtab_command<P>*)cmd; break; case LC_SEGMENT_SPLIT_INFO: _splitSegInfoCmd = (macho_linkedit_data_command<P>*)cmd; break; case LC_DYLD_INFO: case LC_DYLD_INFO_ONLY: _dyldInfo = (macho_dyld_info_command<P>*)cmd; break; case LC_DYLD_EXPORTS_TRIE: _exportTrie = (macho_linkedit_data_command<P>*)cmd; break; case macho_segment_command<P>::CMD: segCmd =( macho_segment_command<P>*)cmd; _segCmds.push_back(segCmd); if ( strcmp(segCmd->segname(), "__LINKEDIT") == 0 ) { _linkeditBias = (uint8_t*)(segCmd->vmaddr() + _cacheSlide - segCmd->fileoff()); _linkeditSize = (uint32_t)segCmd->vmsize(); _linkeditAddr = segCmd->vmaddr(); } else if ( strcmp(segCmd->segname(), "__TEXT") == 0 ) { _textSegStartAddr = (pint_t)segCmd->vmaddr(); const macho_section<P>* const sectionsStart = (macho_section<P>*)((char*)segCmd + sizeof(macho_segment_command<P>)); const macho_section<P>* const sectionsEnd = §ionsStart[segCmd->nsects()]; for (const macho_section<P>* sect = sectionsStart; sect < sectionsEnd; ++sect) { ++sectionIndex; if ( strcmp(sect->sectname(), "__text") == 0 ) { _textSection = sect; _textSectionIndex = sectionIndex; } else if ( ((sect->flags() & SECTION_TYPE) == S_SYMBOL_STUBS) && (sect->size() != 0) ) { _stubSection = sect; _stubSectionIndex = sectionIndex; } } } break; } cmd = (const macho_load_command<P>*)(((uint8_t*)cmd)+cmd->cmdsize()); } } template <typename P> uint32_t StubOptimizer<P>::lazyPointerAddrFromArmStub(const uint8_t* stubInstructions, uint32_t stubVMAddr) { uint32_t stubInstr1 = E::get32(*(uint32_t*)stubInstructions); uint32_t stubInstr2 = E::get32(*(uint32_t*)(stubInstructions+4)); uint32_t stubInstr3 = E::get32(*(uint32_t*)(stubInstructions+8)); int32_t stubData = E::get32(*(uint32_t*)(stubInstructions+12)); if ( stubInstr1 != 0xe59fc004 ) { _diagnostics.warning("first instruction of stub (0x%08X) is not 'ldr ip, pc + 12' for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } if ( stubInstr2 != 0xe08fc00c ) { _diagnostics.warning("second instruction of stub (0x%08X) is not 'add ip, pc, ip' for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } if ( stubInstr3 != 0xe59cf000 ) { _diagnostics.warning("third instruction of stub (0x%08X) is not 'ldr pc, [ip]' for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } return stubVMAddr + 12 + stubData; } template <typename P> uint64_t StubOptimizer<P>::lazyPointerAddrFromArm64Stub(const uint8_t* stubInstructions, uint64_t stubVMAddr) { uint32_t stubInstr1 = E::get32(*(uint32_t*)stubInstructions); if ( (stubInstr1 & 0x9F00001F) != 0x90000010 ) { _diagnostics.warning("first instruction of stub (0x%08X) is not ADRP for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } int32_t adrpValue = ((stubInstr1 & 0x00FFFFE0) >> 3) | ((stubInstr1 & 0x60000000) >> 29); if ( stubInstr1 & 0x00800000 ) adrpValue |= 0xFFF00000; uint32_t stubInstr2 = E::get32(*(uint32_t*)(stubInstructions + 4)); if ( (stubInstr2 & 0xFFC003FF) != 0xF9400210 ) { _diagnostics.warning("second instruction of stub (0x%08X) is not LDR for stub at addr 0x%0llX in %s", stubInstr2, (uint64_t)stubVMAddr, _dylibID); return 0; } uint32_t ldrValue = ((stubInstr2 >> 10) & 0x00000FFF); return (stubVMAddr & (-4096)) + adrpValue*4096 + ldrValue*8; } #if SUPPORT_ARCH_arm64_32 template <typename P> uint64_t StubOptimizer<P>::lazyPointerAddrFromArm64_32Stub(const uint8_t* stubInstructions, uint64_t stubVMAddr) { uint32_t stubInstr1 = E::get32(*(uint32_t*)stubInstructions); if ( (stubInstr1 & 0x9F00001F) != 0x90000010 ) { _diagnostics.warning("first instruction of stub (0x%08X) is not ADRP for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } int32_t adrpValue = ((stubInstr1 & 0x00FFFFE0) >> 3) | ((stubInstr1 & 0x60000000) >> 29); if ( stubInstr1 & 0x00800000 ) adrpValue |= 0xFFF00000; uint32_t stubInstr2 = E::get32(*(uint32_t*)(stubInstructions + 4)); if ( (stubInstr2 & 0xFFC003FF) != 0xB9400210 ) { _diagnostics.warning("second instruction of stub (0x%08X) is not LDR for stub at addr 0x%0llX in %s", stubInstr2, (uint64_t)stubVMAddr, _dylibID); return 0; } uint32_t ldrValue = ((stubInstr2 >> 10) & 0x00000FFF); return (stubVMAddr & (-4096)) + adrpValue*4096 + ldrValue*4; // LDR Wn has a scale factor of 4 } #endif #if SUPPORT_ARCH_arm64e template <typename P> uint64_t StubOptimizer<P>::lazyPointerAddrFromArm64eStub(const uint8_t* stubInstructions, uint64_t stubVMAddr) { uint32_t stubInstr1 = E::get32(*(uint32_t*)stubInstructions); // ADRP X17, dyld_mageLoaderCache@page if ( (stubInstr1 & 0x9F00001F) != 0x90000011 ) { _diagnostics.warning("first instruction of stub (0x%08X) is not ADRP for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } int32_t adrpValue = ((stubInstr1 & 0x00FFFFE0) >> 3) | ((stubInstr1 & 0x60000000) >> 29); if ( stubInstr1 & 0x00800000 ) adrpValue |= 0xFFF00000; // ADD X17, X17, dyld_mageLoaderCache@pageoff uint32_t stubInstr2 = E::get32(*(uint32_t*)(stubInstructions + 4)); if ( (stubInstr2 & 0xFFC003FF) != 0x91000231 ) { _diagnostics.warning("second instruction of stub (0x%08X) is not ADD for stub at addr 0x%0llX in %s", stubInstr2, (uint64_t)stubVMAddr, _dylibID); return 0; } uint32_t addValue = ((stubInstr2 & 0x003FFC00) >> 10); // LDR X16, [X17] uint32_t stubInstr3 = E::get32(*(uint32_t*)(stubInstructions + 8)); if ( stubInstr3 != 0xF9400230 ) { _diagnostics.warning("second instruction of stub (0x%08X) is not LDR for stub at addr 0x%0llX in %s", stubInstr2, (uint64_t)stubVMAddr, _dylibID); return 0; } return (stubVMAddr & (-4096)) + adrpValue*4096 + addValue; } #endif template <typename P> void StubOptimizer<P>::buildStubMap(const std::unordered_set<std::string>& neverStubEliminate) { // find all stubs and lazy pointers const macho_nlist<P>* symbolTable = (const macho_nlist<P>*)(&_linkeditBias[_symTabCmd->symoff()]); const char* symbolStrings = (char*)(&_linkeditBias[_symTabCmd->stroff()]); const uint32_t* const indirectTable = (uint32_t*)(&_linkeditBias[_dynSymTabCmd->indirectsymoff()]); const macho_load_command<P>* const cmds = (macho_load_command<P>*)((uint8_t*)_mh + sizeof(macho_header<P>)); const uint32_t cmd_count = _mh->ncmds(); const macho_load_command<P>* cmd = cmds; for (uint32_t i = 0; i < cmd_count; ++i) { if ( cmd->cmd() == macho_segment_command<P>::CMD ) { macho_segment_command<P>* seg = (macho_segment_command<P>*)cmd; macho_section<P>* const sectionsStart = (macho_section<P>*)((char*)seg + sizeof(macho_segment_command<P>)); macho_section<P>* const sectionsEnd = §ionsStart[seg->nsects()]; for(macho_section<P>* sect = sectionsStart; sect < sectionsEnd; ++sect) { if ( sect->size() == 0 ) continue; unsigned sectionType = (sect->flags() & SECTION_TYPE); const uint32_t indirectTableOffset = sect->reserved1(); if ( sectionType == S_SYMBOL_STUBS ) { const uint32_t stubSize = sect->reserved2(); _stubCount = (uint32_t)(sect->size() / stubSize); pint_t stubVMAddr = (pint_t)sect->addr(); for (uint32_t j=0; j < _stubCount; ++j, stubVMAddr += stubSize) { uint32_t symbolIndex = E::get32(indirectTable[indirectTableOffset + j]); switch ( symbolIndex ) { case INDIRECT_SYMBOL_ABS: case INDIRECT_SYMBOL_LOCAL: case INDIRECT_SYMBOL_ABS | INDIRECT_SYMBOL_LOCAL: break; default: if ( symbolIndex >= _symTabCmd->nsyms() ) { _diagnostics.warning("symbol index out of range (%d of %d) for stub at addr 0x%0llX in %s", symbolIndex, _symTabCmd->nsyms(), (uint64_t)stubVMAddr, _dylibID); continue; } const macho_nlist<P>* sym = &symbolTable[symbolIndex]; uint32_t stringOffset = sym->n_strx(); if ( stringOffset > _symTabCmd->strsize() ) { _diagnostics.warning("symbol string offset out of range (%u of %u) for stub at addr 0x%0llX in %s", stringOffset, sym->n_strx(), (uint64_t)stubVMAddr, _dylibID); continue; } const char* symName = &symbolStrings[stringOffset]; if ( neverStubEliminate.count(symName) ) { //fprintf(stderr, "stubVMAddr=0x%llX, not bypassing stub to %s in %s because target is interposable\n", (uint64_t)stubVMAddr, symName, _dylibID); _stubsLeftInterposable++; continue; } const uint8_t* stubInstrs = (uint8_t*)(long)stubVMAddr + _cacheSlide; pint_t targetLPAddr = 0; switch ( _mh->cputype() ) { case CPU_TYPE_ARM64: #if SUPPORT_ARCH_arm64e if (cpuSubtype() == CPU_SUBTYPE_ARM64E) targetLPAddr = (pint_t)lazyPointerAddrFromArm64eStub(stubInstrs, stubVMAddr); else #endif targetLPAddr = (pint_t)lazyPointerAddrFromArm64Stub(stubInstrs, stubVMAddr); break; #if SUPPORT_ARCH_arm64_32 case CPU_TYPE_ARM64_32: if (cpuSubtype() == CPU_SUBTYPE_ARM64_32_V8) targetLPAddr = (pint_t)lazyPointerAddrFromArm64_32Stub(stubInstrs, stubVMAddr); break; #endif case CPU_TYPE_ARM: targetLPAddr = (pint_t)lazyPointerAddrFromArmStub(stubInstrs, (uint32_t)stubVMAddr); break; } if ( targetLPAddr != 0 ) _stubAddrToLPAddr[stubVMAddr] = targetLPAddr; break; } } } else if ( (sectionType == S_LAZY_SYMBOL_POINTERS) || (sectionType == S_NON_LAZY_SYMBOL_POINTERS) ) { pint_t lpVMAddr; pint_t* lpContent = (pint_t*)(sect->addr() + _cacheSlide); uint32_t elementCount = (uint32_t)(sect->size() / sizeof(pint_t)); uint64_t textSegStartAddr = _segCmds[0]->vmaddr(); uint64_t textSegEndAddr = _segCmds[0]->vmaddr() + _segCmds[0]->vmsize(); pint_t lpValue; for (uint32_t j=0; j < elementCount; ++j) { uint32_t symbolIndex = E::get32(indirectTable[indirectTableOffset + j]); switch ( symbolIndex ) { case INDIRECT_SYMBOL_ABS: case INDIRECT_SYMBOL_LOCAL: case INDIRECT_SYMBOL_LOCAL|INDIRECT_SYMBOL_ABS: break; default: lpValue = (pint_t)P::getP(lpContent[j]); lpVMAddr = (pint_t)sect->addr() + j * sizeof(pint_t); if ( symbolIndex >= _symTabCmd->nsyms() ) { _diagnostics.warning("symbol index out of range (%d of %d) for lazy pointer at addr 0x%0llX in %s", symbolIndex, _symTabCmd->nsyms(), (uint64_t)lpVMAddr, _dylibID); continue; } const macho_nlist<P>* sym = &symbolTable[symbolIndex]; uint32_t stringOffset = sym->n_strx(); if ( stringOffset > _symTabCmd->strsize() ) { _diagnostics.warning("symbol string offset out of range (%u of %u) for lazy pointer at addr 0x%0llX in %s", stringOffset, sym->n_strx(), (uint64_t)lpVMAddr, _dylibID); continue; } const char* symName = &symbolStrings[stringOffset]; if ( (lpValue > textSegStartAddr) && (lpValue< textSegEndAddr) ) { //fprintf(stderr, "skipping lazy pointer at 0x%0lX to %s in %s because target is within dylib\n", (long)lpVMAddr, symName, _dylibID); } else if ( (sizeof(pint_t) == 8) && ((lpValue % 4) != 0) ) { // Only warn on lazy pointers which correspond to call targets if ( sectionType == S_LAZY_SYMBOL_POINTERS ) { _diagnostics.warning("lazy pointer at 0x%0llX does not point to 4-byte aligned address(0x%0llX) for symbol '%s' in %s", (uint64_t)lpVMAddr, (uint64_t)lpValue, symName, _dylibID); } } else { _lpAddrToTargetAddr[lpVMAddr] = lpValue; _targetAddrToName[lpValue] = symName; } break; } } } } } cmd = (const macho_load_command<P>*)(((uint8_t*)cmd)+cmd->cmdsize()); } } template <typename P> void StubOptimizer<P>::forEachCallSiteToAStub(CallSiteHandler handler) { if (_diagnostics.hasError()) return; const uint8_t* infoStart = &_linkeditBias[_splitSegInfoCmd->dataoff()]; const uint8_t* infoEnd = &infoStart[_splitSegInfoCmd->datasize()]; if ( *infoStart++ != DYLD_CACHE_ADJ_V2_FORMAT ) { _diagnostics.error("malformed split seg info in %s", _dylibID); return; } uint8_t* textSectionContent = (uint8_t*)(_textSection->addr() + _cacheSlide); // Whole :== <count> FromToSection+ // FromToSection :== <from-sect-index> <to-sect-index> <count> ToOffset+ // ToOffset :== <to-sect-offset-delta> <count> FromOffset+ // FromOffset :== <kind> <count> <from-sect-offset-delta> const uint8_t* p = infoStart; uint64_t sectionCount = read_uleb128(p, infoEnd); for (uint64_t i=0; i < sectionCount; ++i) { uint64_t fromSectionIndex = read_uleb128(p, infoEnd); uint64_t toSectionIndex = read_uleb128(p, infoEnd); uint64_t toOffsetCount = read_uleb128(p, infoEnd); uint64_t toSectionOffset = 0; for (uint64_t j=0; j < toOffsetCount; ++j) { uint64_t toSectionDelta = read_uleb128(p, infoEnd); uint64_t fromOffsetCount = read_uleb128(p, infoEnd); toSectionOffset += toSectionDelta; for (uint64_t k=0; k < fromOffsetCount; ++k) { uint64_t kind = read_uleb128(p, infoEnd); if ( kind > 13 ) { _diagnostics.error("bad kind (%llu) value in %s\n", kind, _dylibID); } uint64_t fromSectDeltaCount = read_uleb128(p, infoEnd); uint64_t fromSectionOffset = 0; for (uint64_t l=0; l < fromSectDeltaCount; ++l) { uint64_t delta = read_uleb128(p, infoEnd); fromSectionOffset += delta; if ( (fromSectionIndex == _textSectionIndex) && (toSectionIndex == _stubSectionIndex) ) { uint32_t* instrPtr = (uint32_t*)(textSectionContent + fromSectionOffset); uint64_t instrAddr = _textSection->addr() + fromSectionOffset; uint64_t stubAddr = _stubSection->addr() + toSectionOffset; uint32_t instruction = E::get32(*instrPtr); _branchToStubCount++; if ( handler(kind, instrAddr, stubAddr, instruction) ) { E::set32(*instrPtr, instruction); } } } } } } } /// Extract displacement from a thumb b/bl/blx instruction. template <typename P> int32_t StubOptimizer<P>::getDisplacementFromThumbBranch(uint32_t instruction, uint32_t instrAddr) { bool is_blx = ((instruction & 0xD000F800) == 0xC000F000); uint32_t s = (instruction >> 10) & 0x1; uint32_t j1 = (instruction >> 29) & 0x1; uint32_t j2 = (instruction >> 27) & 0x1; uint32_t imm10 = instruction & 0x3FF; uint32_t imm11 = (instruction >> 16) & 0x7FF; uint32_t i1 = (j1 == s); uint32_t i2 = (j2 == s); uint32_t dis = (s << 24) | (i1 << 23) | (i2 << 22) | (imm10 << 12) | (imm11 << 1); int32_t sdis = dis; int32_t result = s ? (sdis | 0xFE000000) : sdis; if ( is_blx && (instrAddr & 0x2) ) { // The thumb blx instruction always has low bit of imm11 as zero. The way // a 2-byte aligned blx can branch to a 4-byte aligned ARM target is that // the blx instruction always 4-byte aligns the pc before adding the // displacement from the blx. We must emulate that when decoding this. result -= 2; } return result; } /// Update a thumb b/bl/blx instruction, switching bl <-> blx as needed. template <typename P> uint32_t StubOptimizer<P>::setDisplacementInThumbBranch(uint32_t instruction, uint32_t instrAddr, int32_t displacement, bool targetIsThumb) { if ( (displacement > 16777214) || (displacement < (-16777216)) ) { _diagnostics.error("thumb branch out of range at 0x%0X in %s", instrAddr, _dylibID); return 0; } bool is_bl = ((instruction & 0xD000F800) == 0xD000F000); bool is_blx = ((instruction & 0xD000F800) == 0xC000F000); bool is_b = ((instruction & 0xD000F800) == 0x9000F000); uint32_t newInstruction = (instruction & 0xD000F800); if (is_bl || is_blx) { if (targetIsThumb) { newInstruction = 0xD000F000; // Use bl } else { newInstruction = 0xC000F000; // Use blx // See note in getDisplacementFromThumbBranch() about blx. if (instrAddr & 0x2) displacement += 2; } } else if (is_b) { if ( !targetIsThumb ) { _diagnostics.error("no pc-rel thumb branch instruction that switches to arm mode at 0x%0X in %s", instrAddr, _dylibID); return 0; } } else { _diagnostics.error("not b/bl/blx at 0x%0X in %s", instrAddr, _dylibID); return 0; } uint32_t s = (uint32_t)(displacement >> 24) & 0x1; uint32_t i1 = (uint32_t)(displacement >> 23) & 0x1; uint32_t i2 = (uint32_t)(displacement >> 22) & 0x1; uint32_t imm10 = (uint32_t)(displacement >> 12) & 0x3FF; uint32_t imm11 = (uint32_t)(displacement >> 1) & 0x7FF; uint32_t j1 = (i1 == s); uint32_t j2 = (i2 == s); uint32_t nextDisp = (j1 << 13) | (j2 << 11) | imm11; uint32_t firstDisp = (s << 10) | imm10; newInstruction |= (nextDisp << 16) | firstDisp; return newInstruction; } template <typename P> void StubOptimizer<P>::optimizeArmCallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr) { forEachCallSiteToAStub([&](uint8_t kind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction) -> bool { if ( kind == DYLD_CACHE_ADJ_V2_THUMB_BR22 ) { bool is_bl = ((instruction & 0xD000F800) == 0xD000F000); bool is_blx = ((instruction & 0xD000F800) == 0xC000F000); bool is_b = ((instruction & 0xD000F800) == 0x9000F000); if ( !is_bl && !is_blx && !is_b ){ _diagnostics.warning("non-branch instruction at 0x%0llX in %s", callSiteAddr, _dylibID); return false; } int32_t brDelta = getDisplacementFromThumbBranch(instruction, (uint32_t)callSiteAddr); pint_t targetAddr = (pint_t)callSiteAddr + 4 + brDelta; if ( targetAddr != stubAddr ) { _diagnostics.warning("stub target mismatch at callsite 0x%0llX in %s", callSiteAddr, _dylibID); return false; } // ignore branch if not to a known stub const auto& pos = _stubAddrToLPAddr.find(targetAddr); if ( pos == _stubAddrToLPAddr.end() ) return false; // ignore branch if lazy pointer is not known (resolver or interposable) uint64_t lpAddr = pos->second; const auto& pos2 = _lpAddrToTargetAddr.find((pint_t)lpAddr); if ( pos2 == _lpAddrToTargetAddr.end() ) return false; uint64_t finalTargetAddr = pos2->second; int64_t deltaToFinalTarget = finalTargetAddr - (callSiteAddr + 4); // if final target within range, change to branch there directly if ( (deltaToFinalTarget > -b16MegLimit) && (deltaToFinalTarget < b16MegLimit) ) { bool targetIsThumb = (finalTargetAddr & 1); instruction = setDisplacementInThumbBranch(instruction, (uint32_t)callSiteAddr, (int32_t)deltaToFinalTarget, targetIsThumb); if (_diagnostics.hasError()) return false; _branchOptimizedToDirectCount++; return true; } // try to re-use an existing optimized stub const auto& pos3 = targetAddrToOptStubAddr.find(finalTargetAddr); if ( pos3 != targetAddrToOptStubAddr.end() ) { uint64_t existingStub = pos3->second; if ( existingStub != stubAddr ) { int64_t deltaToOptStub = existingStub - (callSiteAddr + 4); if ( (deltaToOptStub > -b16MegLimit) && (deltaToOptStub < b16MegLimit) ) { bool targetIsThumb = (existingStub & 1); instruction = setDisplacementInThumbBranch(instruction, (uint32_t)callSiteAddr, (int32_t)deltaToOptStub, targetIsThumb); if (_diagnostics.hasError()) return false; _branchToReUsedOptimizedStubCount++; return true; } } } // leave as BL to stub, but optimize the stub _stubsToOptimize.insert(stubAddr); targetAddrToOptStubAddr[finalTargetAddr] = stubAddr; _branchToOptimizedStubCount++; return false; } else if ( kind == DYLD_CACHE_ADJ_V2_ARM_BR24 ) { // too few of these to be worth trying to optimize } return false; }); if (_diagnostics.hasError()) return; } template <typename P> void StubOptimizer<P>::optimizeArmStubs() { for (const auto& stubEntry : _stubAddrToLPAddr) { pint_t stubVMAddr = stubEntry.first; pint_t lpVMAddr = stubEntry.second; const auto& pos = _lpAddrToTargetAddr.find(lpVMAddr); if ( pos == _lpAddrToTargetAddr.end() ) return; pint_t targetVMAddr = pos->second; int32_t delta = (int32_t)(targetVMAddr - (stubVMAddr + 12)); uint32_t* stubInstructions = (uint32_t*)((uint8_t*)(long)stubVMAddr + _cacheSlide); assert(stubInstructions[0] == 0xe59fc004); stubInstructions[0] = 0xe59fc000; // ldr ip, L0 stubInstructions[1] = 0xe08ff00c; // add pc, pc, ip stubInstructions[2] = delta; // L0: .long xxxx stubInstructions[3] = 0xe7ffdefe; // trap _stubOptimizedCount++; } } template <typename P> void StubOptimizer<P>::optimizeArm64Stubs() { for (const uint64_t stubVMAddr : _stubsToOptimize ) { pint_t lpVMAddr = _stubAddrToLPAddr[(pint_t)stubVMAddr]; const auto& pos = _lpAddrToTargetAddr.find(lpVMAddr); if ( pos == _lpAddrToTargetAddr.end() ) return; pint_t targetVMAddr = pos->second; int64_t adrpDelta = (targetVMAddr & -4096) - (stubVMAddr & -4096); // Note: ADRP/ADD can only span +/-4GB uint32_t* stubInstructions = (uint32_t*)((uint8_t*)(long)stubVMAddr + _cacheSlide); bool rightInstr1 = ((stubInstructions[0] & 0x9F00001F) == 0x90000010); // ADRP X16, lp@page bool rightInstr2 = ((stubInstructions[1] & 0xFFC003FF) == 0xF9400210); // LDR X16, [X16, lp@pageoff] bool rightInstr3 = (stubInstructions[2] == 0xD61F0200); // BR X16 if ( rightInstr1 && rightInstr2 && rightInstr3 ) { uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (targetVMAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 _stubOptimizedCount++; } } } #if SUPPORT_ARCH_arm64e template <typename P> void StubOptimizer<P>::optimizeArm64eStubs() { for (const uint64_t stubVMAddr : _stubsToOptimize ) { pint_t lpVMAddr = _stubAddrToLPAddr[(pint_t)stubVMAddr]; const auto& pos = _lpAddrToTargetAddr.find(lpVMAddr); if ( pos == _lpAddrToTargetAddr.end() ) return; pint_t targetVMAddr = pos->second; int64_t adrpDelta = (targetVMAddr & -4096) - (stubVMAddr & -4096); // Note: ADRP/ADD can only span +/-4GB uint32_t* stubInstructions = (uint32_t*)((uint8_t*)(long)stubVMAddr + _cacheSlide); bool rightInstr1 = ((stubInstructions[0] & 0x9F00001F) == 0x90000011); // ADRP X17, lp@page bool rightInstr2 = ((stubInstructions[1] & 0xFFC003FF) == 0x91000231); // ADD X17, [X17, lp@pageoff] bool rightInstr3 = (stubInstructions[2] == 0xF9400230); // LDR X16, [X17] bool rightInstr4 = (stubInstructions[3] == 0xD71F0A11); // BRAA X16, X17 if ( rightInstr1 && rightInstr2 && rightInstr3 && rightInstr4) { uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (targetVMAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 stubInstructions[3] = 0xD4200020; // TRAP _stubOptimizedCount++; } } } #endif #if SUPPORT_ARCH_arm64_32 template <typename P> void StubOptimizer<P>::optimizeArm64_32Stubs() { for (const uint64_t stubVMAddr : _stubsToOptimize ) { pint_t lpVMAddr = _stubAddrToLPAddr[(pint_t)stubVMAddr]; const auto& pos = _lpAddrToTargetAddr.find(lpVMAddr); if ( pos == _lpAddrToTargetAddr.end() ) return; pint_t targetVMAddr = pos->second; int64_t adrpDelta = (targetVMAddr & -4096) - (stubVMAddr & -4096); uint32_t* stubInstructions = (uint32_t*)((uint8_t*)(long)stubVMAddr + _cacheSlide); bool rightInstr1 = ((stubInstructions[0] & 0x9F00001F) == 0x90000010); // ADRP X16, lp@page bool rightInstr2 = ((stubInstructions[1] & 0xFFC003FF) == 0xB9400210); // LDR W16, [X16, lp@pageoff] bool rightInstr3 = (stubInstructions[2] == 0xD61F0200); // BR X16 if ( rightInstr1 && rightInstr2 && rightInstr3 ) { uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (targetVMAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 _stubOptimizedCount++; } } } #endif template <typename P> void StubOptimizer<P>::optimizeArm64CallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr) { forEachCallSiteToAStub([&](uint8_t kind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction) -> bool { if ( kind != DYLD_CACHE_ADJ_V2_ARM64_BR26 ) return false; // skip all but BL or B if ( (instruction & 0x7C000000) != 0x14000000 ) return false; // compute target of branch instruction int32_t brDelta = (instruction & 0x03FFFFFF) << 2; if ( brDelta & 0x08000000 ) brDelta |= 0xF0000000; uint64_t targetAddr = callSiteAddr + (int64_t)brDelta; if ( targetAddr != stubAddr ) { _diagnostics.warning("stub target mismatch"); return false; } // ignore branch if not to a known stub const auto& pos = _stubAddrToLPAddr.find((pint_t)targetAddr); if ( pos == _stubAddrToLPAddr.end() ) return false; // ignore branch if lazy pointer is not known (resolver or interposable) uint64_t lpAddr = pos->second; const auto& pos2 = _lpAddrToTargetAddr.find((pint_t)lpAddr); if ( pos2 == _lpAddrToTargetAddr.end() ) return false; uint64_t finalTargetAddr = pos2->second; int64_t deltaToFinalTarget = finalTargetAddr - callSiteAddr; // if final target within range, change to branch there directly if ( (deltaToFinalTarget > -b128MegLimit) && (deltaToFinalTarget < b128MegLimit) ) { instruction= (instruction & 0xFC000000) | ((deltaToFinalTarget >> 2) & 0x03FFFFFF); _branchOptimizedToDirectCount++; return true; } // try to re-use an existing optimized stub const auto& pos3 = targetAddrToOptStubAddr.find((pint_t)finalTargetAddr); if ( pos3 != targetAddrToOptStubAddr.end() ) { uint64_t existingStub = pos3->second; if ( existingStub != stubAddr ) { int64_t deltaToOptStub = existingStub - callSiteAddr; if ( (deltaToOptStub > -b128MegLimit) && (deltaToOptStub < b128MegLimit) ) { instruction = (instruction & 0xFC000000) | ((deltaToOptStub >> 2) & 0x03FFFFFF); _branchToReUsedOptimizedStubCount++; return true; } } } // leave as BL to stub, but optimize the stub _stubsToOptimize.insert(stubAddr); targetAddrToOptStubAddr[(pint_t)finalTargetAddr] = (pint_t)stubAddr; _branchToOptimizedStubCount++; return false; }); if (_diagnostics.hasError()) return; } template <typename P> void StubOptimizer<P>::optimizeCallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr) { if ( _textSection == NULL ) return; if ( _stubSection == NULL ) return; switch ( _mh->cputype() ) { case CPU_TYPE_ARM64: optimizeArm64CallSites(targetAddrToOptStubAddr); #if SUPPORT_ARCH_arm64e if (cpuSubtype() == CPU_SUBTYPE_ARM64E) optimizeArm64eStubs(); else #endif optimizeArm64Stubs(); break; #if SUPPORT_ARCH_arm64_32 case CPU_TYPE_ARM64_32: optimizeArm64CallSites(targetAddrToOptStubAddr); optimizeArm64_32Stubs(); break; #endif case CPU_TYPE_ARM: optimizeArmCallSites(targetAddrToOptStubAddr); optimizeArmStubs(); break; } if ( verbose ) { _diagnostics.verbose("dylib has %6u BLs to %4u stubs. Changed %5u, %5u, %5u BLs to use direct branch, optimized stub, neighbor's optimized stub. " "%5u stubs left interposable, %4u stubs optimized. path=%s\n", _branchToStubCount, _stubCount, _branchOptimizedToDirectCount, _branchToOptimizedStubCount, _branchToReUsedOptimizedStubCount, _stubsLeftInterposable, _stubOptimizedCount, _dylibID); } } template <typename P> void bypassStubs(std::vector<std::pair<const mach_header*, const char*>> images, const std::string& archName, int64_t cacheSlide, uint64_t cacheUnslidAddr, const DyldSharedCache* dyldCache, const char* const neverStubEliminateSymbols[], Diagnostics& diags) { std::unordered_map<uint64_t, uint64_t> targetAddrToOptStubAddr; diags.verbose("Stub elimination optimization:\n"); // construct a StubOptimizer for each image __block std::vector<StubOptimizer<P>*> optimizers; for (std::pair<const mach_header*, const char*> image : images) { optimizers.push_back(new StubOptimizer<P>(cacheSlide, cacheUnslidAddr, archName, (macho_header<P>*)image.first, image.second, diags)); } // build set of functions to never stub-eliminate because tools may need to override them std::unordered_set<std::string> neverStubEliminate; for (const char* const* p=neverStubEliminateSymbols; *p != nullptr; ++p) { neverStubEliminate.insert(*p); } #if !BUILDING_APP_CACHE_UTIL // Customer shared caches support overriding libdispatch if ( dyldCache != nullptr ) { for (StubOptimizer<P>* op : optimizers) { if ( dyldCache->isOverridablePath(op->dylibID()) ) { // add all exports const uint8_t* exportsStart = op->exportsTrie(); const uint8_t* exportsEnd = exportsStart + op->exportsTrieSize(); std::vector<ExportInfoTrie::Entry> exports; if ( !ExportInfoTrie::parseTrie(exportsStart, exportsEnd, exports) ) { diags.error("malformed exports trie in %s", op->dylibID()); return; } for(const ExportInfoTrie::Entry& entry : exports) { neverStubEliminate.insert(entry.name); } } } } #endif // build maps of stubs-to-lp and lp-to-target for (StubOptimizer<P>* op : optimizers) op->buildStubMap(neverStubEliminate); // optimize call sites to by-pass stubs or jump through island for (StubOptimizer<P>* op : optimizers) op->optimizeCallSites(targetAddrToOptStubAddr); // write total optimization info uint32_t callSiteCount = 0; uint32_t callSiteDirectOptCount = 0; for (StubOptimizer<P>* op : optimizers) { callSiteCount += op->_branchToStubCount; callSiteDirectOptCount += op->_branchOptimizedToDirectCount; } diags.verbose(" cache contains %u call sites of which %u were direct bound\n", callSiteCount, callSiteDirectOptCount); // clean up for (StubOptimizer<P>* op : optimizers) delete op; } void CacheBuilder::optimizeAwayStubs(const std::vector<std::pair<const mach_header*, const char*>>& images, int64_t cacheSlide, uint64_t cacheUnslidAddr, const DyldSharedCache* dyldCache, const char* const neverStubEliminateSymbols[]) { std::unordered_map<uint64_t, uint64_t> targetAddrToOptStubAddr; std::string archName = _options.archs->name(); #if SUPPORT_ARCH_arm64_32 if ( startsWith(archName, "arm64_32") ) { bypassStubs<Pointer32<LittleEndian> >(images, archName, cacheSlide, cacheUnslidAddr, dyldCache, neverStubEliminateSymbols, _diagnostics); return; } #endif if ( startsWith(archName, "arm64") ) { bypassStubs<Pointer64<LittleEndian> >(images, archName, cacheSlide, cacheUnslidAddr, dyldCache, neverStubEliminateSymbols, _diagnostics); return; } if ( archName == "armv7k" ) { bypassStubs<Pointer32<LittleEndian> >(images, archName, cacheSlide, cacheUnslidAddr, dyldCache, neverStubEliminateSymbols, _diagnostics); return; } // no stub optimization done for other arches } |