darling-dyld/dyld3/MachOLoaded.cpp
2023-04-30 11:26:23 -07:00

1426 lines
62 KiB
C++

/*
* 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 <sys/types.h>
#include <sys/stat.h>
#include <sys/errno.h>
#include <sys/mman.h>
#include <mach/mach.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <assert.h>
#include <mach-o/reloc.h>
#include <mach-o/nlist.h>
extern "C" {
#include <corecrypto/ccdigest.h>
#include <corecrypto/ccsha1.h>
#include <corecrypto/ccsha2.h>
}
#include "MachOFile.h"
#include "MachOLoaded.h"
#include "CodeSigningTypes.h"
namespace dyld3 {
void MachOLoaded::getLinkEditLoadCommands(Diagnostics& diag, LinkEditInfo& result) const
{
result.dyldInfo = nullptr;
result.exportsTrie = nullptr;
result.chainedFixups = nullptr;
result.symTab = nullptr;
result.dynSymTab = nullptr;
result.splitSegInfo = nullptr;
result.functionStarts = nullptr;
result.dataInCode = nullptr;
result.codeSig = nullptr;
__block bool hasUUID = false;
__block bool hasMinVersion = false;
__block bool hasEncrypt = false;
forEachLoadCommand(diag, ^(const load_command* cmd, bool& stop) {
switch ( cmd->cmd ) {
case LC_DYLD_INFO:
case LC_DYLD_INFO_ONLY:
if ( cmd->cmdsize != sizeof(dyld_info_command) )
diag.error("LC_DYLD_INFO load command size wrong");
else if ( result.dyldInfo != nullptr )
diag.error("multiple LC_DYLD_INFO load commands");
result.dyldInfo = (dyld_info_command*)cmd;
break;
case LC_DYLD_EXPORTS_TRIE:
if ( cmd->cmdsize != sizeof(linkedit_data_command) )
diag.error("LC_DYLD_EXPORTS_TRIE load command size wrong");
else if ( result.exportsTrie != nullptr )
diag.error("multiple LC_DYLD_EXPORTS_TRIE load commands");
result.exportsTrie = (linkedit_data_command*)cmd;
break;
case LC_DYLD_CHAINED_FIXUPS:
if ( cmd->cmdsize != sizeof(linkedit_data_command) )
diag.error("LC_DYLD_CHAINED_FIXUPS load command size wrong");
else if ( result.chainedFixups != nullptr )
diag.error("multiple LC_DYLD_CHAINED_FIXUPS load commands");
result.chainedFixups = (linkedit_data_command*)cmd;
break;
case LC_SYMTAB:
if ( cmd->cmdsize != sizeof(symtab_command) )
diag.error("LC_SYMTAB load command size wrong");
else if ( result.symTab != nullptr )
diag.error("multiple LC_SYMTAB load commands");
result.symTab = (symtab_command*)cmd;
break;
case LC_DYSYMTAB:
if ( cmd->cmdsize != sizeof(dysymtab_command) )
diag.error("LC_DYSYMTAB load command size wrong");
else if ( result.dynSymTab != nullptr )
diag.error("multiple LC_DYSYMTAB load commands");
result.dynSymTab = (dysymtab_command*)cmd;
break;
case LC_SEGMENT_SPLIT_INFO:
if ( cmd->cmdsize != sizeof(linkedit_data_command) )
diag.error("LC_SEGMENT_SPLIT_INFO load command size wrong");
else if ( result.splitSegInfo != nullptr )
diag.error("multiple LC_SEGMENT_SPLIT_INFO load commands");
result.splitSegInfo = (linkedit_data_command*)cmd;
break;
case LC_FUNCTION_STARTS:
if ( cmd->cmdsize != sizeof(linkedit_data_command) )
diag.error("LC_FUNCTION_STARTS load command size wrong");
else if ( result.functionStarts != nullptr )
diag.error("multiple LC_FUNCTION_STARTS load commands");
result.functionStarts = (linkedit_data_command*)cmd;
break;
case LC_DATA_IN_CODE:
if ( cmd->cmdsize != sizeof(linkedit_data_command) )
diag.error("LC_DATA_IN_CODE load command size wrong");
else if ( result.dataInCode != nullptr )
diag.error("multiple LC_DATA_IN_CODE load commands");
result.dataInCode = (linkedit_data_command*)cmd;
break;
case LC_CODE_SIGNATURE:
if ( cmd->cmdsize != sizeof(linkedit_data_command) )
diag.error("LC_CODE_SIGNATURE load command size wrong");
else if ( result.codeSig != nullptr )
diag.error("multiple LC_CODE_SIGNATURE load commands");
result.codeSig = (linkedit_data_command*)cmd;
break;
case LC_UUID:
if ( cmd->cmdsize != sizeof(uuid_command) )
diag.error("LC_UUID load command size wrong");
else if ( hasUUID )
diag.error("multiple LC_UUID load commands");
hasUUID = true;
break;
case LC_VERSION_MIN_IPHONEOS:
case LC_VERSION_MIN_MACOSX:
case LC_VERSION_MIN_TVOS:
case LC_VERSION_MIN_WATCHOS:
if ( cmd->cmdsize != sizeof(version_min_command) )
diag.error("LC_VERSION_* load command size wrong");
else if ( hasMinVersion )
diag.error("multiple LC_VERSION_MIN_* load commands");
hasMinVersion = true;
break;
case LC_BUILD_VERSION:
if ( cmd->cmdsize != (sizeof(build_version_command) + ((build_version_command*)cmd)->ntools * sizeof(build_tool_version)) )
diag.error("LC_BUILD_VERSION load command size wrong");
break;
case LC_ENCRYPTION_INFO:
if ( cmd->cmdsize != sizeof(encryption_info_command) )
diag.error("LC_ENCRYPTION_INFO load command size wrong");
else if ( hasEncrypt )
diag.error("multiple LC_ENCRYPTION_INFO load commands");
else if ( is64() )
diag.error("LC_ENCRYPTION_INFO found in 64-bit mach-o");
hasEncrypt = true;
break;
case LC_ENCRYPTION_INFO_64:
if ( cmd->cmdsize != sizeof(encryption_info_command_64) )
diag.error("LC_ENCRYPTION_INFO_64 load command size wrong");
else if ( hasEncrypt )
diag.error("multiple LC_ENCRYPTION_INFO_64 load commands");
else if ( !is64() )
diag.error("LC_ENCRYPTION_INFO_64 found in 32-bit mach-o");
hasEncrypt = true;
break;
}
});
if ( diag.noError() && (result.dynSymTab != nullptr) && (result.symTab == nullptr) )
diag.error("LC_DYSYMTAB but no LC_SYMTAB load command");
}
void MachOLoaded::getLinkEditPointers(Diagnostics& diag, LinkEditInfo& result) const
{
getLinkEditLoadCommands(diag, result);
if ( diag.noError() )
getLayoutInfo(result.layout);
}
const uint8_t* MachOLoaded::getExportsTrie(const LinkEditInfo& leInfo, uint64_t& trieSize) const
{
if ( leInfo.exportsTrie != nullptr) {
trieSize = leInfo.exportsTrie->datasize;
uint64_t offsetInLinkEdit = leInfo.exportsTrie->dataoff - leInfo.layout.linkeditFileOffset;
return (uint8_t*)this + (leInfo.layout.linkeditUnslidVMAddr - leInfo.layout.textUnslidVMAddr) + offsetInLinkEdit;
}
else if ( leInfo.dyldInfo != nullptr ) {
trieSize = leInfo.dyldInfo->export_size;
uint64_t offsetInLinkEdit = leInfo.dyldInfo->export_off - leInfo.layout.linkeditFileOffset;
return (uint8_t*)this + (leInfo.layout.linkeditUnslidVMAddr - leInfo.layout.textUnslidVMAddr) + offsetInLinkEdit;
}
trieSize = 0;
return nullptr;
}
void MachOLoaded::getLayoutInfo(LayoutInfo& result) const
{
forEachSegment(^(const SegmentInfo& info, bool& stop) {
if ( strcmp(info.segName, "__TEXT") == 0 ) {
result.textUnslidVMAddr = (uintptr_t)info.vmAddr;
result.slide = (uintptr_t)(((uint64_t)this) - info.vmAddr);
}
else if ( strcmp(info.segName, "__LINKEDIT") == 0 ) {
result.linkeditUnslidVMAddr = (uintptr_t)info.vmAddr;
result.linkeditFileOffset = (uint32_t)info.fileOffset;
result.linkeditFileSize = (uint32_t)info.fileSize;
result.linkeditSegIndex = info.segIndex;
}
result.lastSegIndex = info.segIndex;
});
}
bool MachOLoaded::hasExportTrie(uint32_t& runtimeOffset, uint32_t& size) const
{
runtimeOffset = 0;
size = 0;
Diagnostics diag;
LinkEditInfo leInfo;
getLinkEditPointers(diag, leInfo);
diag.assertNoError(); // any malformations in the file should have been caught by earlier validate() call
if ( diag.hasError() )
return false;
uint64_t trieSize;
if ( const uint8_t* trie = getExportsTrie(leInfo, trieSize) ) {
runtimeOffset = (uint32_t)(trie - (uint8_t*)this);
size = (uint32_t)trieSize;
return true;
}
return false;
}
#if BUILDING_LIBDYLD
// this is only used by dlsym() at runtime. All other binding is done when the closure is built.
bool MachOLoaded::hasExportedSymbol(const char* symbolName, DependentToMachOLoaded finder, void** result,
bool* resultPointsToInstructions) const
{
typedef void* (*ResolverFunc)(void);
ResolverFunc resolver;
Diagnostics diag;
FoundSymbol foundInfo;
if ( findExportedSymbol(diag, symbolName, false, foundInfo, finder) ) {
switch ( foundInfo.kind ) {
case FoundSymbol::Kind::headerOffset: {
*result = (uint8_t*)foundInfo.foundInDylib + foundInfo.value;
*resultPointsToInstructions = false;
int64_t slide = foundInfo.foundInDylib->getSlide();
foundInfo.foundInDylib->forEachSection(^(const SectionInfo& sectInfo, bool malformedSectionRange, bool& stop) {
uint64_t sectStartAddr = sectInfo.sectAddr + slide;
uint64_t sectEndAddr = sectStartAddr + sectInfo.sectSize;
if ( ((uint64_t)*result >= sectStartAddr) && ((uint64_t)*result < sectEndAddr) ) {
*resultPointsToInstructions = (sectInfo.sectFlags & S_ATTR_PURE_INSTRUCTIONS) || (sectInfo.sectFlags & S_ATTR_SOME_INSTRUCTIONS);
stop = true;
}
});
break;
}
case FoundSymbol::Kind::absolute:
*result = (void*)(long)foundInfo.value;
*resultPointsToInstructions = false;
break;
case FoundSymbol::Kind::resolverOffset:
// foundInfo.value contains "stub".
// in dlsym() we want to call resolver function to get final function address
resolver = (ResolverFunc)((uint8_t*)foundInfo.foundInDylib + foundInfo.resolverFuncOffset);
*result = (*resolver)();
// FIXME: Set this properly
*resultPointsToInstructions = true;
break;
}
return true;
}
return false;
}
#endif // BUILDING_LIBDYLD
bool MachOLoaded::findExportedSymbol(Diagnostics& diag, const char* symbolName, bool weakImport, FoundSymbol& foundInfo, DependentToMachOLoaded findDependent) const
{
LinkEditInfo leInfo;
getLinkEditPointers(diag, leInfo);
if ( diag.hasError() )
return false;
uint64_t trieSize;
if ( const uint8_t* trieStart = getExportsTrie(leInfo, trieSize) ) {
const uint8_t* trieEnd = trieStart + trieSize;
const uint8_t* node = trieWalk(diag, trieStart, trieEnd, symbolName);
if ( node == nullptr ) {
// symbol not exported from this image. Seach any re-exported dylibs
__block unsigned depIndex = 0;
__block bool foundInReExportedDylib = false;
forEachDependentDylib(^(const char* loadPath, bool isWeak, bool isReExport, bool isUpward, uint32_t compatVersion, uint32_t curVersion, bool& stop) {
if ( isReExport && findDependent ) {
if ( const MachOLoaded* depMH = findDependent(this, depIndex) ) {
if ( depMH->findExportedSymbol(diag, symbolName, weakImport, foundInfo, findDependent) ) {
stop = true;
foundInReExportedDylib = true;
}
}
}
++depIndex;
});
return foundInReExportedDylib;
}
const uint8_t* p = node;
const uint64_t flags = read_uleb128(diag, p, trieEnd);
if ( flags & EXPORT_SYMBOL_FLAGS_REEXPORT ) {
if ( !findDependent )
return false;
// re-export from another dylib, lookup there
const uint64_t ordinal = read_uleb128(diag, p, trieEnd);
const char* importedName = (char*)p;
if ( importedName[0] == '\0' )
importedName = symbolName;
if ( (ordinal == 0) || (ordinal > dependentDylibCount()) ) {
diag.error("re-export ordinal %lld out of range for %s", ordinal, symbolName);
return false;
}
uint32_t depIndex = (uint32_t)(ordinal-1);
if ( const MachOLoaded* depMH = findDependent(this, depIndex) ) {
return depMH->findExportedSymbol(diag, importedName, weakImport, foundInfo, findDependent);
}
else if (weakImport) {
return false;
}
else {
diag.error("dependent dylib %lld not found for re-exported symbol %s", ordinal, symbolName);
return false;
}
}
foundInfo.kind = FoundSymbol::Kind::headerOffset;
foundInfo.isThreadLocal = false;
foundInfo.isWeakDef = false;
foundInfo.foundInDylib = this;
foundInfo.value = read_uleb128(diag, p, trieEnd);
foundInfo.resolverFuncOffset = 0;
foundInfo.foundSymbolName = symbolName;
if ( diag.hasError() )
return false;
switch ( flags & EXPORT_SYMBOL_FLAGS_KIND_MASK ) {
case EXPORT_SYMBOL_FLAGS_KIND_REGULAR:
if ( flags & EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER ) {
foundInfo.kind = FoundSymbol::Kind::headerOffset;
foundInfo.resolverFuncOffset = (uint32_t)read_uleb128(diag, p, trieEnd);
}
else {
foundInfo.kind = FoundSymbol::Kind::headerOffset;
}
if ( flags & EXPORT_SYMBOL_FLAGS_WEAK_DEFINITION )
foundInfo.isWeakDef = true;
break;
case EXPORT_SYMBOL_FLAGS_KIND_THREAD_LOCAL:
foundInfo.isThreadLocal = true;
break;
case EXPORT_SYMBOL_FLAGS_KIND_ABSOLUTE:
foundInfo.kind = FoundSymbol::Kind::absolute;
break;
default:
diag.error("unsupported exported symbol kind. flags=%llu at node offset=0x%0lX", flags, (long)(node-trieStart));
return false;
}
return true;
}
else {
// this is an old binary (before macOS 10.6), scan the symbol table
foundInfo.foundInDylib = nullptr;
forEachGlobalSymbol(diag, ^(const char* aSymbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, bool& stop) {
if ( strcmp(aSymbolName, symbolName) == 0 ) {
foundInfo.kind = FoundSymbol::Kind::headerOffset;
foundInfo.isThreadLocal = false;
foundInfo.foundInDylib = this;
foundInfo.value = n_value - leInfo.layout.textUnslidVMAddr;
foundInfo.resolverFuncOffset = 0;
foundInfo.foundSymbolName = symbolName;
stop = true;
}
});
if ( foundInfo.foundInDylib == nullptr ) {
// symbol not exported from this image. Search any re-exported dylibs
__block unsigned depIndex = 0;
forEachDependentDylib(^(const char* loadPath, bool isWeak, bool isReExport, bool isUpward, uint32_t compatVersion, uint32_t curVersion, bool& stop) {
if ( isReExport && findDependent ) {
if ( const MachOLoaded* depMH = findDependent(this, depIndex) ) {
if ( depMH->findExportedSymbol(diag, symbolName, weakImport, foundInfo, findDependent) ) {
stop = true;
}
}
}
++depIndex;
});
}
return (foundInfo.foundInDylib != nullptr);
}
}
intptr_t MachOLoaded::getSlide() const
{
Diagnostics diag;
__block intptr_t slide = 0;
forEachLoadCommand(diag, ^(const load_command* cmd, bool& stop) {
if ( cmd->cmd == LC_SEGMENT_64 ) {
const segment_command_64* seg = (segment_command_64*)cmd;
if ( strcmp(seg->segname, "__TEXT") == 0 ) {
slide = (uintptr_t)(((uint64_t)this) - seg->vmaddr);
stop = true;
}
}
else if ( cmd->cmd == LC_SEGMENT ) {
const segment_command* seg = (segment_command*)cmd;
if ( strcmp(seg->segname, "__TEXT") == 0 ) {
slide = (uintptr_t)(((uint64_t)this) - seg->vmaddr);
stop = true;
}
}
});
diag.assertNoError(); // any malformations in the file should have been caught by earlier validate() call
return slide;
}
const uint8_t* MachOLoaded::getLinkEditContent(const LayoutInfo& info, uint32_t fileOffset) const
{
uint32_t offsetInLinkedit = fileOffset - info.linkeditFileOffset;
uintptr_t linkeditStartAddr = info.linkeditUnslidVMAddr + info.slide;
return (uint8_t*)(linkeditStartAddr + offsetInLinkedit);
}
void MachOLoaded::forEachGlobalSymbol(Diagnostics& diag, void (^callback)(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, bool& stop)) const
{
LinkEditInfo leInfo;
getLinkEditPointers(diag, leInfo);
if ( diag.hasError() )
return;
const bool is64Bit = is64();
if ( leInfo.symTab != nullptr ) {
uint32_t globalsStartIndex = 0;
uint32_t globalsCount = leInfo.symTab->nsyms;
if ( leInfo.dynSymTab != nullptr ) {
globalsStartIndex = leInfo.dynSymTab->iextdefsym;
globalsCount = leInfo.dynSymTab->nextdefsym;
}
uint32_t maxStringOffset = leInfo.symTab->strsize;
const char* stringPool = (char*)getLinkEditContent(leInfo.layout, leInfo.symTab->stroff);
const struct nlist* symbols = (struct nlist*) (getLinkEditContent(leInfo.layout, leInfo.symTab->symoff));
const struct nlist_64* symbols64 = (struct nlist_64*)symbols;
bool stop = false;
for (uint32_t i=0; (i < globalsCount) && !stop; ++i) {
if ( is64Bit ) {
const struct nlist_64& sym = symbols64[globalsStartIndex+i];
if ( sym.n_un.n_strx > maxStringOffset )
continue;
if ( (sym.n_type & N_EXT) && ((sym.n_type & N_TYPE) == N_SECT) && ((sym.n_type & N_STAB) == 0) )
callback(&stringPool[sym.n_un.n_strx], sym.n_value, sym.n_type, sym.n_sect, sym.n_desc, stop);
}
else {
const struct nlist& sym = symbols[globalsStartIndex+i];
if ( sym.n_un.n_strx > maxStringOffset )
continue;
if ( (sym.n_type & N_EXT) && ((sym.n_type & N_TYPE) == N_SECT) && ((sym.n_type & N_STAB) == 0) )
callback(&stringPool[sym.n_un.n_strx], sym.n_value, sym.n_type, sym.n_sect, sym.n_desc, stop);
}
}
}
}
void MachOLoaded::forEachLocalSymbol(Diagnostics& diag, void (^callback)(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, bool& stop)) const
{
LinkEditInfo leInfo;
getLinkEditPointers(diag, leInfo);
if ( diag.hasError() )
return;
const bool is64Bit = is64();
if ( leInfo.symTab != nullptr ) {
uint32_t localsStartIndex = 0;
uint32_t localsCount = leInfo.symTab->nsyms;
if ( leInfo.dynSymTab != nullptr ) {
localsStartIndex = leInfo.dynSymTab->ilocalsym;
localsCount = leInfo.dynSymTab->nlocalsym;
}
uint32_t maxStringOffset = leInfo.symTab->strsize;
const char* stringPool = (char*)getLinkEditContent(leInfo.layout, leInfo.symTab->stroff);
const struct nlist* symbols = (struct nlist*) (getLinkEditContent(leInfo.layout, leInfo.symTab->symoff));
const struct nlist_64* symbols64 = (struct nlist_64*)(getLinkEditContent(leInfo.layout, leInfo.symTab->symoff));
bool stop = false;
for (uint32_t i=0; (i < localsCount) && !stop; ++i) {
if ( is64Bit ) {
const struct nlist_64& sym = symbols64[localsStartIndex+i];
if ( sym.n_un.n_strx > maxStringOffset )
continue;
if ( ((sym.n_type & N_EXT) == 0) && ((sym.n_type & N_TYPE) == N_SECT) && ((sym.n_type & N_STAB) == 0) )
callback(&stringPool[sym.n_un.n_strx], sym.n_value, sym.n_type, sym.n_sect, sym.n_desc, stop);
}
else {
const struct nlist& sym = symbols[localsStartIndex+i];
if ( sym.n_un.n_strx > maxStringOffset )
continue;
if ( ((sym.n_type & N_EXT) == 0) && ((sym.n_type & N_TYPE) == N_SECT) && ((sym.n_type & N_STAB) == 0) )
callback(&stringPool[sym.n_un.n_strx], sym.n_value, sym.n_type, sym.n_sect, sym.n_desc, stop);
}
}
}
}
uint32_t MachOLoaded::dependentDylibCount() const
{
__block uint32_t count = 0;
forEachDependentDylib(^(const char* loadPath, bool isWeak, bool isReExport, bool isUpward, uint32_t compatVersion, uint32_t curVersion, bool& stop) {
++count;
});
return count;
}
const char* MachOLoaded::dependentDylibLoadPath(uint32_t depIndex) const
{
__block const char* foundLoadPath = nullptr;
__block uint32_t curDepIndex = 0;
forEachDependentDylib(^(const char* loadPath, bool isWeak, bool isReExport, bool isUpward, uint32_t compatVersion, uint32_t curVersion, bool& stop) {
if ( curDepIndex == depIndex ) {
foundLoadPath = loadPath;
stop = true;
}
++curDepIndex;
});
return foundLoadPath;
}
const char* MachOLoaded::segmentName(uint32_t targetSegIndex) const
{
__block const char* result = nullptr;
forEachSegment(^(const SegmentInfo& info, bool& stop) {
if ( targetSegIndex == info.segIndex ) {
result = info.segName;
stop = true;
}
});
return result;
}
bool MachOLoaded::findClosestFunctionStart(uint64_t address, uint64_t* functionStartAddress) const
{
Diagnostics diag;
LinkEditInfo leInfo;
getLinkEditPointers(diag, leInfo);
if ( diag.hasError() )
return false;
if ( leInfo.functionStarts == nullptr )
return false;
const uint8_t* starts = getLinkEditContent(leInfo.layout, leInfo.functionStarts->dataoff);
const uint8_t* startsEnd = starts + leInfo.functionStarts->datasize;
uint64_t lastAddr = (uint64_t)(long)this;
uint64_t runningAddr = lastAddr;
while (diag.noError()) {
uint64_t value = read_uleb128(diag, starts, startsEnd);
if ( value == 0 )
break;
lastAddr = runningAddr;
runningAddr += value;
//fprintf(stderr, " addr=0x%08llX\n", runningAddr);
if ( runningAddr > address ) {
*functionStartAddress = lastAddr;
return true;
}
};
return false;
}
bool MachOLoaded::findClosestSymbol(uint64_t address, const char** symbolName, uint64_t* symbolAddr) const
{
Diagnostics diag;
LinkEditInfo leInfo;
getLinkEditPointers(diag, leInfo);
if ( diag.hasError() )
return false;
if ( (leInfo.symTab == nullptr) || (leInfo.dynSymTab == nullptr) )
return false;
uint64_t targetUnslidAddress = address - leInfo.layout.slide;
// find section index the address is in to validate n_sect
__block uint32_t sectionIndexForTargetAddress = 0;
forEachSection(^(const SectionInfo& sectInfo, bool malformedSectionRange, bool& stop) {
++sectionIndexForTargetAddress;
if ( (sectInfo.sectAddr <= targetUnslidAddress) && (targetUnslidAddress < sectInfo.sectAddr+sectInfo.sectSize) ) {
stop = true;
}
});
uint32_t maxStringOffset = leInfo.symTab->strsize;
const char* stringPool = (char*)getLinkEditContent(leInfo.layout, leInfo.symTab->stroff);
const struct nlist* symbols = (struct nlist*) (getLinkEditContent(leInfo.layout, leInfo.symTab->symoff));
if ( is64() ) {
const struct nlist_64* symbols64 = (struct nlist_64*)symbols;
const struct nlist_64* bestSymbol = nullptr;
// first walk all global symbols
const struct nlist_64* const globalsStart = &symbols64[leInfo.dynSymTab->iextdefsym];
const struct nlist_64* const globalsEnd = &globalsStart[leInfo.dynSymTab->nextdefsym];
for (const struct nlist_64* s = globalsStart; s < globalsEnd; ++s) {
if ( (s->n_type & N_TYPE) == N_SECT ) {
if ( bestSymbol == nullptr ) {
if ( (s->n_value <= targetUnslidAddress) && (s->n_sect == sectionIndexForTargetAddress) )
bestSymbol = s;
}
else if ( (s->n_value <= targetUnslidAddress) && (bestSymbol->n_value < s->n_value) && (s->n_sect == sectionIndexForTargetAddress) ) {
bestSymbol = s;
}
}
}
// next walk all local symbols
const struct nlist_64* const localsStart = &symbols64[leInfo.dynSymTab->ilocalsym];
const struct nlist_64* const localsEnd = &localsStart[leInfo.dynSymTab->nlocalsym];
for (const struct nlist_64* s = localsStart; s < localsEnd; ++s) {
if ( ((s->n_type & N_TYPE) == N_SECT) && ((s->n_type & N_STAB) == 0) ) {
if ( bestSymbol == nullptr ) {
if ( (s->n_value <= targetUnslidAddress) && (s->n_sect == sectionIndexForTargetAddress) )
bestSymbol = s;
}
else if ( (s->n_value <= targetUnslidAddress) && (bestSymbol->n_value < s->n_value) && (s->n_sect == sectionIndexForTargetAddress) ) {
bestSymbol = s;
}
}
}
if ( bestSymbol != NULL ) {
*symbolAddr = bestSymbol->n_value + leInfo.layout.slide;
if ( bestSymbol->n_un.n_strx < maxStringOffset )
*symbolName = &stringPool[bestSymbol->n_un.n_strx];
return true;
}
}
else {
const struct nlist* bestSymbol = nullptr;
// first walk all global symbols
const struct nlist* const globalsStart = &symbols[leInfo.dynSymTab->iextdefsym];
const struct nlist* const globalsEnd = &globalsStart[leInfo.dynSymTab->nextdefsym];
for (const struct nlist* s = globalsStart; s < globalsEnd; ++s) {
if ( (s->n_type & N_TYPE) == N_SECT ) {
if ( bestSymbol == nullptr ) {
if ( (s->n_value <= targetUnslidAddress) && (s->n_sect == sectionIndexForTargetAddress) )
bestSymbol = s;
}
else if ( (s->n_value <= targetUnslidAddress) && (bestSymbol->n_value < s->n_value) && (s->n_sect == sectionIndexForTargetAddress) ) {
bestSymbol = s;
}
}
}
// next walk all local symbols
const struct nlist* const localsStart = &symbols[leInfo.dynSymTab->ilocalsym];
const struct nlist* const localsEnd = &localsStart[leInfo.dynSymTab->nlocalsym];
for (const struct nlist* s = localsStart; s < localsEnd; ++s) {
if ( ((s->n_type & N_TYPE) == N_SECT) && ((s->n_type & N_STAB) == 0) ) {
if ( bestSymbol == nullptr ) {
if ( (s->n_value <= targetUnslidAddress) && (s->n_sect == sectionIndexForTargetAddress) )
bestSymbol = s;
}
else if ( (s->n_value <= targetUnslidAddress) && (bestSymbol->n_value < s->n_value) && (s->n_sect == sectionIndexForTargetAddress) ) {
bestSymbol = s;
}
}
}
if ( bestSymbol != nullptr ) {
#if __arm__
if ( bestSymbol->n_desc & N_ARM_THUMB_DEF )
*symbolAddr = (bestSymbol->n_value | 1) + leInfo.layout.slide;
else
*symbolAddr = bestSymbol->n_value + leInfo.layout.slide;
#else
*symbolAddr = bestSymbol->n_value + leInfo.layout.slide;
#endif
if ( bestSymbol->n_un.n_strx < maxStringOffset )
*symbolName = &stringPool[bestSymbol->n_un.n_strx];
return true;
}
}
return false;
}
const void* MachOLoaded::findSectionContent(const char* segName, const char* sectName, uint64_t& size) const
{
__block const void* result = nullptr;
forEachSection(^(const SectionInfo& sectInfo, bool malformedSectionRange, bool& stop) {
if ( (strcmp(sectInfo.sectName, sectName) == 0) && (strcmp(sectInfo.segInfo.segName, segName) == 0) ) {
size = sectInfo.sectSize;
result = (void*)(sectInfo.sectAddr + getSlide());
}
});
return result;
}
bool MachOLoaded::intersectsRange(uintptr_t start, uintptr_t length) const
{
__block bool result = false;
uintptr_t slide = getSlide();
forEachSegment(^(const SegmentInfo& info, bool& stop) {
if ( (info.vmAddr+info.vmSize+slide >= start) && (info.vmAddr+slide < start+length) )
result = true;
});
return result;
}
const uint8_t* MachOLoaded::trieWalk(Diagnostics& diag, const uint8_t* start, const uint8_t* end, const char* symbol)
{
STACK_ALLOC_OVERFLOW_SAFE_ARRAY(uint32_t, visitedNodeOffsets, 128);
visitedNodeOffsets.push_back(0);
const uint8_t* p = start;
while ( p < end ) {
uint64_t terminalSize = *p++;
if ( terminalSize > 127 ) {
// except for re-export-with-rename, all terminal sizes fit in one byte
--p;
terminalSize = read_uleb128(diag, p, end);
if ( diag.hasError() )
return nullptr;
}
if ( (*symbol == '\0') && (terminalSize != 0) ) {
return p;
}
const uint8_t* children = p + terminalSize;
if ( children > end ) {
//diag.error("malformed trie node, terminalSize=0x%llX extends past end of trie\n", terminalSize);
return nullptr;
}
uint8_t childrenRemaining = *children++;
p = children;
uint64_t nodeOffset = 0;
for (; childrenRemaining > 0; --childrenRemaining) {
const char* ss = symbol;
bool wrongEdge = false;
// scan whole edge to get to next edge
// if edge is longer than target symbol name, don't read past end of symbol name
char c = *p;
while ( c != '\0' ) {
if ( !wrongEdge ) {
if ( c != *ss )
wrongEdge = true;
++ss;
}
++p;
c = *p;
}
if ( wrongEdge ) {
// advance to next child
++p; // skip over zero terminator
// skip over uleb128 until last byte is found
while ( (*p & 0x80) != 0 )
++p;
++p; // skip over last byte of uleb128
if ( p > end ) {
diag.error("malformed trie node, child node extends past end of trie\n");
return nullptr;
}
}
else {
// the symbol so far matches this edge (child)
// so advance to the child's node
++p;
nodeOffset = read_uleb128(diag, p, end);
if ( diag.hasError() )
return nullptr;
if ( (nodeOffset == 0) || ( &start[nodeOffset] > end) ) {
diag.error("malformed trie child, nodeOffset=0x%llX out of range\n", nodeOffset);
return nullptr;
}
symbol = ss;
break;
}
}
if ( nodeOffset != 0 ) {
if ( nodeOffset > (uint64_t)(end-start) ) {
diag.error("malformed trie child, nodeOffset=0x%llX out of range\n", nodeOffset);
return nullptr;
}
// check for cycles
for (uint32_t aVisitedNodeOffset : visitedNodeOffsets) {
if ( aVisitedNodeOffset == nodeOffset ) {
diag.error("malformed trie child, cycle to nodeOffset=0x%llX\n", nodeOffset);
return nullptr;
}
}
visitedNodeOffsets.push_back((uint32_t)nodeOffset);
p = &start[nodeOffset];
}
else
p = end;
}
return nullptr;
}
void MachOLoaded::forEachCDHashOfCodeSignature(const void* codeSigStart, size_t codeSignLen,
void (^callback)(const uint8_t cdHash[20])) const
{
#ifndef DARLING
forEachCodeDirectoryBlob(codeSigStart, codeSignLen, ^(const void *cdBuffer) {
const CS_CodeDirectory* cd = (const CS_CodeDirectory*)cdBuffer;
uint32_t cdLength = htonl(cd->length);
uint8_t cdHash[20];
if ( cd->hashType == CS_HASHTYPE_SHA384 ) {
uint8_t digest[CCSHA384_OUTPUT_SIZE];
const struct ccdigest_info* di = ccsha384_di();
ccdigest_di_decl(di, tempBuf); // declares tempBuf array in stack
ccdigest_init(di, tempBuf);
ccdigest_update(di, tempBuf, cdLength, cd);
ccdigest_final(di, tempBuf, digest);
ccdigest_di_clear(di, tempBuf);
// cd-hash of sigs that use SHA384 is the first 20 bytes of the SHA384 of the code digest
memcpy(cdHash, digest, 20);
callback(cdHash);
return;
}
else if ( (cd->hashType == CS_HASHTYPE_SHA256) || (cd->hashType == CS_HASHTYPE_SHA256_TRUNCATED) ) {
uint8_t digest[CCSHA256_OUTPUT_SIZE];
const struct ccdigest_info* di = ccsha256_di();
ccdigest_di_decl(di, tempBuf); // declares tempBuf array in stack
ccdigest_init(di, tempBuf);
ccdigest_update(di, tempBuf, cdLength, cd);
ccdigest_final(di, tempBuf, digest);
ccdigest_di_clear(di, tempBuf);
// cd-hash of sigs that use SHA256 is the first 20 bytes of the SHA256 of the code digest
memcpy(cdHash, digest, 20);
callback(cdHash);
return;
}
else if ( cd->hashType == CS_HASHTYPE_SHA1 ) {
// compute hash directly into return buffer
const struct ccdigest_info* di = ccsha1_di();
ccdigest_di_decl(di, tempBuf); // declares tempBuf array in stack
ccdigest_init(di, tempBuf);
ccdigest_update(di, tempBuf, cdLength, cd);
ccdigest_final(di, tempBuf, cdHash);
ccdigest_di_clear(di, tempBuf);
callback(cdHash);
return;
}
});
#endif
}
// Note, this has to match the kernel
static const uint32_t hashPriorities[] = {
CS_HASHTYPE_SHA1,
CS_HASHTYPE_SHA256_TRUNCATED,
CS_HASHTYPE_SHA256,
CS_HASHTYPE_SHA384,
};
static unsigned int hash_rank(const CS_CodeDirectory *cd)
{
uint32_t type = cd->hashType;
for (uint32_t n = 0; n < sizeof(hashPriorities) / sizeof(hashPriorities[0]); ++n) {
if (hashPriorities[n] == type)
return n + 1;
}
/* not supported */
return 0;
}
// Note, this does NOT match the kernel.
// On watchOS, in main executables, we will record all cd hashes then make sure
// one of the ones we record matches the kernel.
// This list is only for dylibs where we embed the cd hash in the closure instead of the
// mod time and inode
// This is sorted so that we choose sha1 first when checking dylibs
static const uint32_t hashPriorities_watchOS_dylibs[] = {
CS_HASHTYPE_SHA256_TRUNCATED,
CS_HASHTYPE_SHA256,
CS_HASHTYPE_SHA384,
CS_HASHTYPE_SHA1
};
static unsigned int hash_rank_watchOS_dylibs(const CS_CodeDirectory *cd)
{
uint32_t type = cd->hashType;
for (uint32_t n = 0; n < sizeof(hashPriorities_watchOS_dylibs) / sizeof(hashPriorities_watchOS_dylibs[0]); ++n) {
if (hashPriorities_watchOS_dylibs[n] == type)
return n + 1;
}
/* not supported */
return 0;
}
// This calls the callback for all code directories required for a given platform/binary combination.
// On watchOS main executables this is all cd hashes.
// On watchOS dylibs this is only the single cd hash we need (by rank defined by dyld, not the kernel).
// On all other platforms this always returns a single best cd hash (ranked to match the kernel).
// Note the callback parameter is really a CS_CodeDirectory.
void MachOLoaded::forEachCodeDirectoryBlob(const void* codeSigStart, size_t codeSignLen,
void (^callback)(const void* cd)) const
{
// verify min length of overall code signature
if ( codeSignLen < sizeof(CS_SuperBlob) )
return;
// verify magic at start
const CS_SuperBlob* codeSuperBlob = (CS_SuperBlob*)codeSigStart;
if ( codeSuperBlob->magic != htonl(CSMAGIC_EMBEDDED_SIGNATURE) )
return;
// verify count of sub-blobs not too large
uint32_t subBlobCount = htonl(codeSuperBlob->count);
if ( (codeSignLen-sizeof(CS_SuperBlob))/sizeof(CS_BlobIndex) < subBlobCount )
return;
// Note: The kernel sometimes chooses sha1 on watchOS, and sometimes sha256.
// Embed all of them so that we just need to match any of them
const bool isWatchOS = this->builtForPlatform(Platform::watchOS);
const bool isMainExecutable = this->isMainExecutable();
auto hashRankFn = isWatchOS ? &hash_rank_watchOS_dylibs : &hash_rank;
// walk each sub blob, looking at ones with type CSSLOT_CODEDIRECTORY
const CS_CodeDirectory* bestCd = nullptr;
for (uint32_t i=0; i < subBlobCount; ++i) {
if ( codeSuperBlob->index[i].type == htonl(CSSLOT_CODEDIRECTORY) ) {
// Ok, this is the regular code directory
} else if ( codeSuperBlob->index[i].type >= htonl(CSSLOT_ALTERNATE_CODEDIRECTORIES) && codeSuperBlob->index[i].type <= htonl(CSSLOT_ALTERNATE_CODEDIRECTORY_LIMIT)) {
// Ok, this is the alternative code directory
} else {
continue;
}
uint32_t cdOffset = htonl(codeSuperBlob->index[i].offset);
// verify offset is not out of range
if ( cdOffset > (codeSignLen - sizeof(CS_CodeDirectory)) )
continue;
const CS_CodeDirectory* cd = (CS_CodeDirectory*)((uint8_t*)codeSuperBlob + cdOffset);
uint32_t cdLength = htonl(cd->length);
// verify code directory length not out of range
if ( cdLength > (codeSignLen - cdOffset) )
continue;
// The watch main executable wants to know about all cd hashes
if ( isWatchOS && isMainExecutable ) {
callback(cd);
continue;
}
if ( cd->magic == htonl(CSMAGIC_CODEDIRECTORY) ) {
if ( !bestCd || (hashRankFn(cd) > hashRankFn(bestCd)) )
bestCd = cd;
}
}
// Note this callback won't happen on watchOS as that one was done in the loop
if ( bestCd != nullptr )
callback(bestCd);
}
uint64_t MachOLoaded::ChainedFixupPointerOnDisk::Arm64e::unpackTarget() const
{
assert(this->authBind.bind == 0);
assert(this->authBind.auth == 0);
return ((uint64_t)(this->rebase.high8) << 56) | (this->rebase.target);
}
uint64_t MachOLoaded::ChainedFixupPointerOnDisk::Arm64e::signExtendedAddend() const
{
assert(this->authBind.bind == 1);
assert(this->authBind.auth == 0);
uint64_t addend19 = this->bind.addend;
if ( addend19 & 0x40000 )
return addend19 | 0xFFFFFFFFFFFC0000ULL;
else
return addend19;
}
const char* MachOLoaded::ChainedFixupPointerOnDisk::Arm64e::keyName(uint8_t keyBits)
{
static const char* names[] = {
"IA", "IB", "DA", "DB"
};
assert(keyBits < 4);
return names[keyBits];
}
const char* MachOLoaded::ChainedFixupPointerOnDisk::Arm64e::keyName() const
{
assert(this->authBind.auth == 1);
return keyName(this->authBind.key);
}
uint64_t MachOLoaded::ChainedFixupPointerOnDisk::Arm64e::signPointer(uint64_t unsignedAddr, void* loc, bool addrDiv, uint16_t diversity, uint8_t key)
{
// don't sign NULL
if ( unsignedAddr == 0 )
return 0;
#if __has_feature(ptrauth_calls)
uint64_t extendedDiscriminator = diversity;
if ( addrDiv )
extendedDiscriminator = __builtin_ptrauth_blend_discriminator(loc, extendedDiscriminator);
switch ( key ) {
case 0: // IA
return (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)unsignedAddr, 0, extendedDiscriminator);
case 1: // IB
return (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)unsignedAddr, 1, extendedDiscriminator);
case 2: // DA
return (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)unsignedAddr, 2, extendedDiscriminator);
case 3: // DB
return (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)unsignedAddr, 3, extendedDiscriminator);
}
assert(0 && "invalid signing key");
#else
assert(0 && "arm64e signing only arm64e");
#endif
}
uint64_t MachOLoaded::ChainedFixupPointerOnDisk::Arm64e::signPointer(void* loc, uint64_t target) const
{
assert(this->authBind.auth == 1);
return signPointer(target, loc, authBind.addrDiv, authBind.diversity, authBind.key);
}
uint64_t MachOLoaded::ChainedFixupPointerOnDisk::Generic64::unpackedTarget() const
{
return (((uint64_t)this->rebase.high8) << 56) | (uint64_t)(this->rebase.target);
}
uint64_t MachOLoaded::ChainedFixupPointerOnDisk::Generic64::signExtendedAddend() const
{
uint64_t addend27 = this->bind.addend;
uint64_t top8Bits = addend27 & 0x00007F80000ULL;
uint64_t bottom19Bits = addend27 & 0x0000007FFFFULL;
uint64_t newValue = (top8Bits << 13) | (((uint64_t)(bottom19Bits << 37) >> 37) & 0x00FFFFFFFFFFFFFF);
return newValue;
}
const char* MachOLoaded::ChainedFixupPointerOnDisk::Kernel64::keyName() const
{
static const char* names[] = {
"IA", "IB", "DA", "DB"
};
assert(this->isAuth == 1);
uint8_t keyBits = this->key;
assert(keyBits < 4);
return names[keyBits];
}
bool MachOLoaded::ChainedFixupPointerOnDisk::isRebase(uint16_t pointerFormat, uint64_t preferedLoadAddress, uint64_t& targetRuntimeOffset) const
{
switch (pointerFormat) {
case DYLD_CHAINED_PTR_ARM64E:
case DYLD_CHAINED_PTR_ARM64E_USERLAND:
case DYLD_CHAINED_PTR_ARM64E_USERLAND24:
case DYLD_CHAINED_PTR_ARM64E_KERNEL:
case DYLD_CHAINED_PTR_ARM64E_FIRMWARE:
if ( this->arm64e.bind.bind )
return false;
if ( this->arm64e.authRebase.auth ) {
targetRuntimeOffset = this->arm64e.authRebase.target;
return true;
}
else {
targetRuntimeOffset = this->arm64e.unpackTarget();
if ( (pointerFormat == DYLD_CHAINED_PTR_ARM64E) || (pointerFormat == DYLD_CHAINED_PTR_ARM64E_FIRMWARE) ) {
targetRuntimeOffset -= preferedLoadAddress;
}
return true;
}
break;
case DYLD_CHAINED_PTR_64:
case DYLD_CHAINED_PTR_64_OFFSET:
if ( this->generic64.bind.bind )
return false;
targetRuntimeOffset = this->generic64.unpackedTarget();
if ( pointerFormat == DYLD_CHAINED_PTR_64 )
targetRuntimeOffset -= preferedLoadAddress;
return true;
break;
case DYLD_CHAINED_PTR_64_KERNEL_CACHE:
case DYLD_CHAINED_PTR_X86_64_KERNEL_CACHE:
targetRuntimeOffset = this->kernel64.target;
return true;
break;
case DYLD_CHAINED_PTR_32:
if ( this->generic32.bind.bind )
return false;
targetRuntimeOffset = this->generic32.rebase.target - preferedLoadAddress;
return true;
break;
case DYLD_CHAINED_PTR_32_FIRMWARE:
targetRuntimeOffset = this->firmware32.target - preferedLoadAddress;
return true;
break;
default:
break;
}
assert(0 && "unsupported pointer chain format");
}
bool MachOLoaded::ChainedFixupPointerOnDisk::isBind(uint16_t pointerFormat, uint32_t& bindOrdinal, int64_t& addend) const
{
addend = 0;
switch (pointerFormat) {
case DYLD_CHAINED_PTR_ARM64E:
case DYLD_CHAINED_PTR_ARM64E_USERLAND:
case DYLD_CHAINED_PTR_ARM64E_USERLAND24:
case DYLD_CHAINED_PTR_ARM64E_KERNEL:
case DYLD_CHAINED_PTR_ARM64E_FIRMWARE:
if ( !this->arm64e.authBind.bind )
return false;
if ( this->arm64e.authBind.auth ) {
if ( pointerFormat == DYLD_CHAINED_PTR_ARM64E_USERLAND24 )
bindOrdinal = this->arm64e.authBind24.ordinal;
else
bindOrdinal = this->arm64e.authBind.ordinal;
return true;
}
else {
if ( pointerFormat == DYLD_CHAINED_PTR_ARM64E_USERLAND24 )
bindOrdinal = this->arm64e.bind24.ordinal;
else
bindOrdinal = this->arm64e.bind.ordinal;
addend = this->arm64e.signExtendedAddend();
return true;
}
break;
case DYLD_CHAINED_PTR_64:
case DYLD_CHAINED_PTR_64_OFFSET:
if ( !this->generic64.bind.bind )
return false;
bindOrdinal = this->generic64.bind.ordinal;
addend = this->generic64.bind.addend;
return true;
break;
case DYLD_CHAINED_PTR_32:
if ( !this->generic32.bind.bind )
return false;
bindOrdinal = this->generic32.bind.ordinal;
addend = this->generic32.bind.addend;
return true;
break;
case DYLD_CHAINED_PTR_64_KERNEL_CACHE:
case DYLD_CHAINED_PTR_X86_64_KERNEL_CACHE:
return false;
default:
break;
}
assert(0 && "unsupported pointer chain format");
}
unsigned MachOLoaded::ChainedFixupPointerOnDisk::strideSize(uint16_t pointerFormat)
{
switch (pointerFormat) {
case DYLD_CHAINED_PTR_ARM64E:
case DYLD_CHAINED_PTR_ARM64E_USERLAND:
case DYLD_CHAINED_PTR_ARM64E_USERLAND24:
return 8;
case DYLD_CHAINED_PTR_ARM64E_KERNEL:
case DYLD_CHAINED_PTR_ARM64E_FIRMWARE:
case DYLD_CHAINED_PTR_32_FIRMWARE:
case DYLD_CHAINED_PTR_64:
case DYLD_CHAINED_PTR_64_OFFSET:
case DYLD_CHAINED_PTR_32:
case DYLD_CHAINED_PTR_32_CACHE:
case DYLD_CHAINED_PTR_64_KERNEL_CACHE:
return 4;
case DYLD_CHAINED_PTR_X86_64_KERNEL_CACHE:
return 1;
}
assert(0 && "unsupported pointer chain format");
}
#if BUILDING_DYLD || BUILDING_LIBDYLD
void MachOLoaded::fixupAllChainedFixups(Diagnostics& diag, const dyld_chained_starts_in_image* starts, uintptr_t slide,
Array<const void*> bindTargets, void (^logFixup)(void* loc, void* newValue)) const
{
forEachFixupInAllChains(diag, starts, true, ^(ChainedFixupPointerOnDisk* fixupLoc, const dyld_chained_starts_in_segment* segInfo, bool& stop) {
void* newValue;
switch (segInfo->pointer_format) {
#if __LP64__
#if __has_feature(ptrauth_calls)
case DYLD_CHAINED_PTR_ARM64E:
case DYLD_CHAINED_PTR_ARM64E_KERNEL:
case DYLD_CHAINED_PTR_ARM64E_USERLAND:
case DYLD_CHAINED_PTR_ARM64E_USERLAND24:
if ( fixupLoc->arm64e.authRebase.auth ) {
if ( fixupLoc->arm64e.authBind.bind ) {
uint32_t bindOrdinal = (segInfo->pointer_format == DYLD_CHAINED_PTR_ARM64E_USERLAND24) ? fixupLoc->arm64e.authBind24.ordinal : fixupLoc->arm64e.authBind.ordinal;
if ( bindOrdinal >= bindTargets.count() ) {
diag.error("out of range bind ordinal %d (max %lu)", bindOrdinal, bindTargets.count());
stop = true;
break;
}
else {
// authenticated bind
newValue = (void*)(bindTargets[bindOrdinal]);
if (newValue != 0) // Don't sign missing weak imports
newValue = (void*)fixupLoc->arm64e.signPointer(fixupLoc, (uintptr_t)newValue);
}
}
else {
// authenticated rebase
newValue = (void*)fixupLoc->arm64e.signPointer(fixupLoc, (uintptr_t)this + fixupLoc->arm64e.authRebase.target);
}
}
else {
if ( fixupLoc->arm64e.bind.bind ) {
uint32_t bindOrdinal = (segInfo->pointer_format == DYLD_CHAINED_PTR_ARM64E_USERLAND24) ? fixupLoc->arm64e.bind24.ordinal : fixupLoc->arm64e.bind.ordinal;
if ( bindOrdinal >= bindTargets.count() ) {
diag.error("out of range bind ordinal %d (max %lu)", bindOrdinal, bindTargets.count());
stop = true;
break;
}
else {
// plain bind
newValue = (void*)((long)bindTargets[bindOrdinal] + fixupLoc->arm64e.signExtendedAddend());
}
}
else {
// plain rebase (old format target is vmaddr, new format target is offset)
if ( segInfo->pointer_format == DYLD_CHAINED_PTR_ARM64E )
newValue = (void*)(fixupLoc->arm64e.unpackTarget()+slide);
else
newValue = (void*)((uintptr_t)this + fixupLoc->arm64e.unpackTarget());
}
}
if ( logFixup )
logFixup(fixupLoc, newValue);
fixupLoc->raw64 = (uintptr_t)newValue;
break;
#endif
case DYLD_CHAINED_PTR_64:
case DYLD_CHAINED_PTR_64_OFFSET:
if ( fixupLoc->generic64.bind.bind ) {
if ( fixupLoc->generic64.bind.ordinal >= bindTargets.count() ) {
diag.error("out of range bind ordinal %d (max %lu)", fixupLoc->generic64.bind.ordinal, bindTargets.count());
stop = true;
break;
}
else {
newValue = (void*)((long)bindTargets[fixupLoc->generic64.bind.ordinal] + fixupLoc->generic64.signExtendedAddend());
}
}
else {
// plain rebase (old format target is vmaddr, new format target is offset)
if ( segInfo->pointer_format == DYLD_CHAINED_PTR_64 )
newValue = (void*)(fixupLoc->generic64.unpackedTarget()+slide);
else
newValue = (void*)((uintptr_t)this + fixupLoc->generic64.unpackedTarget());
}
if ( logFixup )
logFixup(fixupLoc, newValue);
fixupLoc->raw64 = (uintptr_t)newValue;
break;
#else
case DYLD_CHAINED_PTR_32:
if ( fixupLoc->generic32.bind.bind ) {
if ( fixupLoc->generic32.bind.ordinal >= bindTargets.count() ) {
diag.error("out of range bind ordinal %d (max %lu)", fixupLoc->generic32.bind.ordinal, bindTargets.count());
stop = true;
break;
}
else {
newValue = (void*)((long)bindTargets[fixupLoc->generic32.bind.ordinal] + fixupLoc->generic32.bind.addend);
}
}
else {
if ( fixupLoc->generic32.rebase.target > segInfo->max_valid_pointer ) {
// handle non-pointers in chain
uint32_t bias = (0x04000000 + segInfo->max_valid_pointer)/2;
newValue = (void*)(fixupLoc->generic32.rebase.target - bias);
}
else {
newValue = (void*)(fixupLoc->generic32.rebase.target + slide);
}
}
if ( logFixup )
logFixup(fixupLoc, newValue);
fixupLoc->raw32 = (uint32_t)(uintptr_t)newValue;
break;
#endif // __LP64__
default:
diag.error("unsupported pointer chain format: 0x%04X", segInfo->pointer_format);
stop = true;
break;
}
});
}
#endif
bool MachOLoaded::walkChain(Diagnostics& diag, ChainedFixupPointerOnDisk* chain, uint16_t pointer_format, bool notifyNonPointers, uint32_t max_valid_pointer,
void (^handler)(ChainedFixupPointerOnDisk* fixupLocation, bool& stop)) const
{
const unsigned stride = ChainedFixupPointerOnDisk::strideSize(pointer_format);
bool stop = false;
bool chainEnd = false;
while (!stop && !chainEnd) {
// copy chain content, in case handler modifies location to final value
ChainedFixupPointerOnDisk chainContent = *chain;
handler(chain, stop);
if ( !stop ) {
switch (pointer_format) {
case DYLD_CHAINED_PTR_ARM64E:
case DYLD_CHAINED_PTR_ARM64E_KERNEL:
case DYLD_CHAINED_PTR_ARM64E_USERLAND:
case DYLD_CHAINED_PTR_ARM64E_USERLAND24:
case DYLD_CHAINED_PTR_ARM64E_FIRMWARE:
if ( chainContent.arm64e.rebase.next == 0 )
chainEnd = true;
else
chain = (ChainedFixupPointerOnDisk*)((uint8_t*)chain + chainContent.arm64e.rebase.next*stride);
break;
case DYLD_CHAINED_PTR_64:
case DYLD_CHAINED_PTR_64_OFFSET:
if ( chainContent.generic64.rebase.next == 0 )
chainEnd = true;
else
chain = (ChainedFixupPointerOnDisk*)((uint8_t*)chain + chainContent.generic64.rebase.next*4);
break;
case DYLD_CHAINED_PTR_32:
if ( chainContent.generic32.rebase.next == 0 )
chainEnd = true;
else {
chain = (ChainedFixupPointerOnDisk*)((uint8_t*)chain + chainContent.generic32.rebase.next*4);
if ( !notifyNonPointers ) {
while ( (chain->generic32.rebase.bind == 0) && (chain->generic32.rebase.target > max_valid_pointer) ) {
// not a real pointer, but a non-pointer co-opted into chain
chain = (ChainedFixupPointerOnDisk*)((uint8_t*)chain + chain->generic32.rebase.next*4);
}
}
}
break;
case DYLD_CHAINED_PTR_64_KERNEL_CACHE:
case DYLD_CHAINED_PTR_X86_64_KERNEL_CACHE:
if ( chainContent.kernel64.next == 0 )
chainEnd = true;
else
chain = (ChainedFixupPointerOnDisk*)((uint8_t*)chain + chainContent.kernel64.next*stride);
break;
case DYLD_CHAINED_PTR_32_FIRMWARE:
if ( chainContent.firmware32.next == 0 )
chainEnd = true;
else
chain = (ChainedFixupPointerOnDisk*)((uint8_t*)chain + chainContent.firmware32.next*4);
break;
default:
diag.error("unknown pointer format 0x%04X", pointer_format);
stop = true;
}
}
}
return stop;
}
void MachOLoaded::forEachFixupChainSegment(Diagnostics& diag, const dyld_chained_starts_in_image* starts,
void (^handler)(const dyld_chained_starts_in_segment* segInfo, uint32_t segIndex, bool& stop)) const
{
bool stopped = false;
for (uint32_t segIndex=0; segIndex < starts->seg_count && !stopped; ++segIndex) {
if ( starts->seg_info_offset[segIndex] == 0 )
continue;
const dyld_chained_starts_in_segment* segInfo = (dyld_chained_starts_in_segment*)((uint8_t*)starts + starts->seg_info_offset[segIndex]);
handler(segInfo, segIndex, stopped);
}
}
void MachOLoaded::forEachFixupInSegmentChains(Diagnostics& diag, const dyld_chained_starts_in_segment* segInfo, bool notifyNonPointers,
void (^handler)(ChainedFixupPointerOnDisk* fixupLocation, const dyld_chained_starts_in_segment* segInfo, bool& stop)) const
{
auto adaptor = ^(ChainedFixupPointerOnDisk* fixupLocation, bool& stop) {
handler(fixupLocation, segInfo, stop);
};
bool stopped = false;
for (uint32_t pageIndex=0; pageIndex < segInfo->page_count && !stopped; ++pageIndex) {
uint16_t offsetInPage = segInfo->page_start[pageIndex];
if ( offsetInPage == DYLD_CHAINED_PTR_START_NONE )
continue;
if ( offsetInPage & DYLD_CHAINED_PTR_START_MULTI ) {
// 32-bit chains which may need multiple starts per page
uint32_t overflowIndex = offsetInPage & ~DYLD_CHAINED_PTR_START_MULTI;
bool chainEnd = false;
while (!stopped && !chainEnd) {
chainEnd = (segInfo->page_start[overflowIndex] & DYLD_CHAINED_PTR_START_LAST);
offsetInPage = (segInfo->page_start[overflowIndex] & ~DYLD_CHAINED_PTR_START_LAST);
uint8_t* pageContentStart = (uint8_t*)this + segInfo->segment_offset + (pageIndex * segInfo->page_size);
ChainedFixupPointerOnDisk* chain = (ChainedFixupPointerOnDisk*)(pageContentStart+offsetInPage);
stopped = walkChain(diag, chain, segInfo->pointer_format, notifyNonPointers, segInfo->max_valid_pointer, adaptor);
++overflowIndex;
}
}
else {
// one chain per page
uint8_t* pageContentStart = (uint8_t*)this + segInfo->segment_offset + (pageIndex * segInfo->page_size);
ChainedFixupPointerOnDisk* chain = (ChainedFixupPointerOnDisk*)(pageContentStart+offsetInPage);
stopped = walkChain(diag, chain, segInfo->pointer_format, notifyNonPointers, segInfo->max_valid_pointer, adaptor);
}
}
}
void MachOLoaded::forEachFixupInAllChains(Diagnostics& diag, const dyld_chained_starts_in_image* starts, bool notifyNonPointers,
void (^handler)(ChainedFixupPointerOnDisk* fixupLocation, const dyld_chained_starts_in_segment* segInfo, bool& stop)) const
{
bool stopped = false;
for (uint32_t segIndex=0; segIndex < starts->seg_count && !stopped; ++segIndex) {
if ( starts->seg_info_offset[segIndex] == 0 )
continue;
const dyld_chained_starts_in_segment* segInfo = (dyld_chained_starts_in_segment*)((uint8_t*)starts + starts->seg_info_offset[segIndex]);
forEachFixupInSegmentChains(diag, segInfo, notifyNonPointers, handler);
}
}
void MachOLoaded::forEachFixupInAllChains(Diagnostics& diag, uint16_t pointer_format, uint32_t starts_count, const uint32_t chain_starts[],
void (^handler)(ChainedFixupPointerOnDisk* fixupLocation, bool& stop)) const
{
for (uint32_t i=0; i < starts_count; ++i) {
ChainedFixupPointerOnDisk* chain = (ChainedFixupPointerOnDisk*)((uint8_t*)this + chain_starts[i]);
if ( walkChain(diag, chain, pointer_format, false, 0, handler) )
break;
}
}
} // namespace dyld3