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AppCacheBuilder.cpp
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/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
*
* Copyright (c) 2014 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 "AppCacheBuilder.h"
#include <mach/mach_time.h>
#include <sys/stat.h>
#include <CoreFoundation/CFArray.h>
#include <CoreFoundation/CFError.h>
#include <CoreFoundation/CFNumber.h>
#include <CoreFoundation/CFPropertyList.h>
#include <CoreFoundation/CFString.h>
#include <CommonCrypto/CommonHMAC.h>
#include <CommonCrypto/CommonDigest.h>
#include <CommonCrypto/CommonDigestSPI.h>
AppCacheBuilder::AppCacheBuilder(const DyldSharedCache::CreateOptions& options,
const Options& appCacheOptions,
const dyld3::closure::FileSystem& fileSystem)
: CacheBuilder(options, fileSystem), appCacheOptions(appCacheOptions)
{
// FIXME: 32-bit support
_is64 = true;
}
AppCacheBuilder::~AppCacheBuilder() {
if (prelinkInfoDict) {
CFRelease(prelinkInfoDict);
}
if (_fullAllocatedBuffer) {
vm_deallocate(mach_task_self(), _fullAllocatedBuffer, _allocatedBufferSize);
}
}
void AppCacheBuilder::makeSortedDylibs(const std::vector<InputDylib>& dylibs)
{
for (const InputDylib& file : dylibs) {
if ( file.dylib.loadedFileInfo.fileContent == nullptr ) {
codelessKexts.push_back(file);
} else {
AppCacheDylibInfo& dylibInfo = sortedDylibs.emplace_back();
dylibInfo.input = &file.dylib;
dylibInfo.dylibID = file.dylibID;
dylibInfo.dependencies = file.dylibDeps;
dylibInfo.infoPlist = file.infoPlist;
dylibInfo.errors = file.errors;
dylibInfo.bundlePath = file.bundlePath;
dylibInfo.stripMode = file.stripMode;
}
}
std::sort(sortedDylibs.begin(), sortedDylibs.end(), [&](const DylibInfo& a, const DylibInfo& b) {
// Sort the kernel first, then kext's
bool isStaticExecutableA = a.input->mappedFile.mh->isStaticExecutable();
bool isStaticExecutableB = b.input->mappedFile.mh->isStaticExecutable();
if (isStaticExecutableA != isStaticExecutableB)
return isStaticExecutableA;
// Sort split seg next
bool splitSegA = a.input->mappedFile.mh->hasSplitSeg();
bool splitSegB = b.input->mappedFile.mh->hasSplitSeg();
if (splitSegA != splitSegB)
return splitSegA;
// Finally sort by path
return a.input->mappedFile.runtimePath < b.input->mappedFile.runtimePath;
});
// Sort codeless kext's by ID
std::sort(codelessKexts.begin(), codelessKexts.end(), [&](const InputDylib& a, const InputDylib& b) {
return a.dylibID < b.dylibID;
});
}
void AppCacheBuilder::forEachCacheDylib(void (^callback)(const dyld3::MachOAnalyzer* ma,
const std::string& dylibID,
DylibStripMode stripMode,
const std::vector<std::string>& dependencies,
Diagnostics& dylibDiag,
bool& stop)) const {
bool stop = false;
for (const AppCacheDylibInfo& dylib : sortedDylibs) {
for (const SegmentMappingInfo& loc : dylib.cacheLocation) {
if (!strcmp(loc.segName, "__TEXT")) {
// Assume __TEXT contains the mach header
callback((const dyld3::MachOAnalyzer*)loc.dstSegment, dylib.dylibID, dylib.stripMode,
dylib.dependencies, *dylib.errors, stop);
break;
}
}
if (stop)
break;
}
}
void AppCacheBuilder::forEachDylibInfo(void (^callback)(const DylibInfo& dylib, Diagnostics& dylibDiag,
cache_builder::ASLR_Tracker& dylibASLRTracker,
const CacheBuilder::DylibSectionCoalescer* sectionCoalescer)) {
for (const AppCacheDylibInfo& dylibInfo : sortedDylibs)
callback(dylibInfo, *dylibInfo.errors, _aslrTracker, &dylibInfo._coalescer);
}
const CacheBuilder::DylibInfo* AppCacheBuilder::getKernelStaticExecutableInputFile() const {
for (const auto& dylib : sortedDylibs) {
const dyld3::MachOAnalyzer* ma = dylib.input->mappedFile.mh;
if ( ma->isStaticExecutable() )
return &dylib;
}
return nullptr;
}
const dyld3::MachOAnalyzer* AppCacheBuilder::getKernelStaticExecutableFromCache() const {
// FIXME: Support reading this from a prebuilt KC
assert(appCacheOptions.cacheKind == Options::AppCacheKind::kernel);
__block const dyld3::MachOAnalyzer* kernelMA = nullptr;
forEachCacheDylib(^(const dyld3::MachOAnalyzer *ma, const std::string &dylibID,
DylibStripMode stripMode, const std::vector<std::string>& dependencies,
Diagnostics& dylibDiag,
bool& stop) {
if ( ma->isStaticExecutable() ) {
kernelMA = ma;
stop = true;
}
});
assert(kernelMA != nullptr);
return kernelMA;
}
void AppCacheBuilder::forEachRegion(void (^callback)(const Region& region)) const {
// cacheHeaderRegion
callback(cacheHeaderRegion);
// readOnlyTextRegion
callback(readOnlyTextRegion);
// -sectcreate
for (const Region& region : customDataRegions)
callback(region);
// readExecuteRegion
if ( readExecuteRegion.sizeInUse != 0 )
callback(readExecuteRegion);
// branchStubsRegion
if ( branchStubsRegion.bufferSize != 0 )
callback(branchStubsRegion);
// textBootExecRegion
if ( textBootExecRegion.sizeInUse != 0 )
callback(textBootExecRegion);
// dataConstRegion
if ( dataConstRegion.sizeInUse != 0 )
callback(dataConstRegion);
// lateConstRegion
if ( lateConstRegion.sizeInUse != 0 )
callback(lateConstRegion);
// dataSptmRegion
if ( dataSptmRegion.sizeInUse != 0 )
callback(dataSptmRegion);
// branchGOTsRegion
if ( branchGOTsRegion.bufferSize != 0 )
callback(branchGOTsRegion);
// readWriteRegion
if ( readWriteRegion.sizeInUse != 0 )
callback(readWriteRegion);
// hibernateRegion
if ( hibernateRegion.sizeInUse != 0 )
callback(hibernateRegion);
// prelinkInfoRegion
if ( prelinkInfoDict != nullptr )
callback(prelinkInfoRegion);
// nonSplitSegRegions
for (const Region& region : nonSplitSegRegions)
callback(region);
// _readOnlyRegion
callback(_readOnlyRegion);
// fixupsRegion
// We don't count this as its not a real region
}
uint64_t AppCacheBuilder::numRegions() const {
__block uint64_t count = 0;
forEachRegion(^(const Region ®ion) {
++count;
});
return count;
}
uint64_t AppCacheBuilder::fixupsPageSize() const {
bool use4K = false;
use4K |= (_options.archs == &dyld3::GradedArchs::x86_64);
use4K |= (_options.archs == &dyld3::GradedArchs::x86_64h);
return use4K ? 4096 : 16384;
}
uint64_t AppCacheBuilder::numWritablePagesToFixup(uint64_t numBytesToFixup) const {
uint64_t pageSize = fixupsPageSize();
assert((numBytesToFixup % pageSize) == 0);
uint64_t numPagesToFixup = numBytesToFixup / pageSize;
return numPagesToFixup;
}
// Returns true if each kext inside the KC needs to be reloadable, ie, have its
// pages reset and its start method rerun. This means we can't pack pages and need
// fixups on each kext individually
bool AppCacheBuilder::fixupsArePerKext() const {
if ( appCacheOptions.cacheKind == Options::AppCacheKind::pageableKC )
return true;
bool isX86 = (_options.archs == &dyld3::GradedArchs::x86_64) || (_options.archs == &dyld3::GradedArchs::x86_64h);
return isX86 && (appCacheOptions.cacheKind == Options::AppCacheKind::auxKC);
}
// x86_64 kext's don't contain stubs for branches so we need to generate some
// if branches cross from one KC to another, eg, from the auxKC to the base KC
uint64_t AppCacheBuilder::numBranchRelocationTargets() {
bool mayHaveBranchRelocations = false;
mayHaveBranchRelocations |= (_options.archs == &dyld3::GradedArchs::x86_64);
mayHaveBranchRelocations |= (_options.archs == &dyld3::GradedArchs::x86_64h);
if ( !mayHaveBranchRelocations )
return 0;
switch (appCacheOptions.cacheKind) {
case Options::AppCacheKind::none:
case Options::AppCacheKind::kernel:
// Nothing to do here as we can't bind from a lower level up to a higher one
return 0;
case Options::AppCacheKind::pageableKC:
case Options::AppCacheKind::kernelCollectionLevel2:
case Options::AppCacheKind::auxKC:
// Any calls in these might be to a lower level so add space for each call target
break;
}
uint64_t totalTargets = 0;
for (const DylibInfo& dylib : sortedDylibs) {
// We need the symbol name and libOrdinal just in case we bind to the same symbol name in 2 different KCs
typedef std::pair<std::string_view, int> Symbol;
struct SymbolHash
{
size_t operator() (const Symbol& symbol) const
{
return std::hash<std::string_view>{}(symbol.first) ^ std::hash<int>{}(symbol.second);
}
};
__block std::unordered_set<Symbol, SymbolHash> seenSymbols;
dylib.input->mappedFile.mh->forEachBind(_diagnostics,
^(uint64_t runtimeOffset, int libOrdinal, uint8_t type,
const char *symbolName, bool weakImport,
bool lazyBind, uint64_t addend, bool &stop) {
if ( type != BIND_TYPE_TEXT_PCREL32 )
return;
seenSymbols.insert({ symbolName, libOrdinal });
}, ^(const char *symbolName) {
});
totalTargets += seenSymbols.size();
}
return totalTargets;
}
bool AppCacheBuilder::hasSancovGateSection() const
{
for ( const AppCacheDylibInfo& dylib : sortedDylibs ) {
const dyld3::MachOAnalyzer* ma = dylib.input->mappedFile.mh;
if ( ma->hasSection("__DATA", "__sancov_gate") )
return true;
}
return false;
}
bool AppCacheBuilder::removeStubs()
{
// Only eliminate stubs in the base kernel collection. We could eliminate stubs
// in the auxKC too, for those calls resolved within the auxKC, but its not worth it right now
if ( appCacheOptions.cacheKind != Options::AppCacheKind::kernel )
return false;
if ( _options.archs != &dyld3::GradedArchs::arm64e )
return false;
if ( hasSancovGateSection() )
return false;
return true;
}
void AppCacheBuilder::parseStubs()
{
if ( !removeStubs() )
return;
for (AppCacheDylibInfo& dylib : sortedDylibs) {
const dyld3::MachOAnalyzer* ma = dylib.input->mappedFile.mh;
// We can only remove sections if we know we have split seg v2 to point to it
uint32_t splitSegSize = 0;
const void* splitSegStart = ma->getSplitSeg(splitSegSize);
if (!splitSegStart)
continue;
if ((*(const uint8_t*)splitSegStart) != DYLD_CACHE_ADJ_V2_FORMAT)
continue;
// Find __TEXT_EXEC __auth_stubs, and remove it if we have it
__block bool lastSectionWasAuthStubs = false;
ma->forEachSection(^(const dyld3::MachOAnalyzer::SectionInfo& sectInfo, bool malformedSectionRange, bool& stop) {
if ( strcmp(sectInfo.segInfo.segName, "__TEXT_EXEC") != 0 )
return;
lastSectionWasAuthStubs = false;
if ( strcmp(sectInfo.sectName, "__auth_stubs") == 0 ) {
// The auth stubs are only valid if the sections is 16-byte stubs
if ( ((sectInfo.sectFlags & SECTION_TYPE) == S_SYMBOL_STUBS) && (sectInfo.reserved2 == 16) )
lastSectionWasAuthStubs = true;
}
});
if ( lastSectionWasAuthStubs )
dylib._coalescer.auth_stubs.sectionIsObliterated = true;
}
}
void AppCacheBuilder::assignSegmentRegionsAndOffsets()
{
// Segments can be re-ordered in memory relative to the order of the LC_SEGMENT load comamnds
// so first make space for all the cache location objects so that we get the order the same
// as the LC_SEGMENTs
for (DylibInfo& dylib : sortedDylibs) {
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
dylib.cacheLocation.push_back({});
});
}
// If we are building the kernel collection, then inherit the base address of the statically linked kernel
const dyld3::MachOAnalyzer* kernelMA = nullptr;
if ( appCacheOptions.cacheKind == Options::AppCacheKind::kernel ) {
for (DylibInfo& dylib : sortedDylibs) {
if ( dylib.input->mappedFile.mh->isStaticExecutable() ) {
kernelMA = dylib.input->mappedFile.mh;
break;
}
}
if ( kernelMA == nullptr ) {
_diagnostics.error("Could not find kernel image");
return;
}
cacheBaseAddress = kernelMA->preferredLoadAddress();
}
// x86_64 doesn't have stubs for kext branches. So work out how many potential targets
// we need to emit stubs for.
uint64_t branchTargetsFromKexts = numBranchRelocationTargets();
uint32_t minimumSegmentAlignmentP2 = 14;
if ( (_options.archs == &dyld3::GradedArchs::x86_64) || (_options.archs == &dyld3::GradedArchs::x86_64h) ) {
minimumSegmentAlignmentP2 = 12;
}
auto getMinAlignment = ^(const dyld3::MachOAnalyzer* ma) {
// The kernel wants to be able to unmap its own segments so always align it.
// And align the pageable KC as each kext can be mapped individually
if ( ma == kernelMA )
return minimumSegmentAlignmentP2;
if ( fixupsArePerKext() )
return minimumSegmentAlignmentP2;
return 0U;
};
{
// __TEXT segments with r/o permissions
__block uint64_t offsetInRegion = 0;
for (DylibInfo& dylib : sortedDylibs) {
bool canBePacked = dylib.input->mappedFile.mh->hasSplitSeg();
if (!canBePacked)
continue;
__block uint64_t textSegVmAddr = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( segInfo.protections != (VM_PROT_READ) )
return;
if ( (strcmp(segInfo.segName, "__DATA_CONST") == 0)
|| (strcmp(segInfo.segName, "__PPLDATA_CONST") == 0)
|| (strcmp(segInfo.segName, "__LASTDATA_CONST") == 0)
|| (strcmp(segInfo.segName, "__LATE_CONST") == 0) )
return;
if ( strcmp(segInfo.segName, "__LINKEDIT") == 0 )
return;
if ( strcmp(segInfo.segName, "__LINKINFO") == 0 )
return;
uint32_t minAlignmentP2 = getMinAlignment(dylib.input->mappedFile.mh);
size_t copySize = std::min((size_t)segInfo.fileSize, (size_t)segInfo.sizeOfSections);
uint64_t dstCacheSegmentSize = align(segInfo.sizeOfSections, minAlignmentP2);
// __CTF is not mapped in to the kernel, so remove it from the final binary.
if ( strcmp(segInfo.segName, "__CTF") == 0 ) {
copySize = 0;
dstCacheSegmentSize = 0;
}
// kxld packs __TEXT so we will do
// Note we align to at least 16-bytes as LDR's can scale up to 16 from their address
// and aligning them less than 16 would break that
offsetInRegion = align(offsetInRegion, std::max(segInfo.p2align, 4U));
offsetInRegion = align(offsetInRegion, minAlignmentP2);
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)dstCacheSegmentSize;
loc.dstCacheFileSize = (uint32_t)copySize;
loc.copySegmentSize = (uint32_t)copySize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &readOnlyTextRegion;
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += dstCacheSegmentSize;
});
}
// kclist needs this segment, even if its empty, so leave it in there
readOnlyTextRegion.bufferSize = align(offsetInRegion, 14);
readOnlyTextRegion.sizeInUse = readOnlyTextRegion.bufferSize;
readOnlyTextRegion.initProt = VM_PROT_READ;
readOnlyTextRegion.maxProt = VM_PROT_READ;
readOnlyTextRegion.name = "__PRELINK_TEXT";
}
// __TEXT segments with r/x permissions
{
// __TEXT segments with r/x permissions
__block uint64_t offsetInRegion = 0;
for (AppCacheDylibInfo& dylib : sortedDylibs) {
bool canBePacked = dylib.input->mappedFile.mh->hasSplitSeg();
if (!canBePacked)
continue;
__block uint64_t textSegVmAddr = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( strcmp(segInfo.segName, "__HIB") == 0 )
return;
if ( (strcmp(segInfo.segName, "__TEXT_BOOT_EXEC") == 0) && dylib.input->mappedFile.mh->isStaticExecutable() )
return;
if ( segInfo.protections != (VM_PROT_READ | VM_PROT_EXECUTE) )
return;
// We may have coalesced the sections at the end of this segment. In that case, shrink the segment to remove them.
__block size_t sizeOfSections = 0;
__block bool foundRemovedSection = false;
dylib.input->mappedFile.mh->forEachSection(^(const dyld3::MachOAnalyzer::SectionInfo §Info, bool malformedSectionRange, bool &stopSection) {
if (strcmp(sectInfo.segInfo.segName, segInfo.segName) != 0)
return;
if ( dylib._coalescer.sectionWasObliterated(segInfo.segName, sectInfo.sectName)) {
foundRemovedSection = true;
} else {
sizeOfSections = sectInfo.sectAddr + sectInfo.sectSize - segInfo.vmAddr;
}
});
if ( !foundRemovedSection )
sizeOfSections = segInfo.sizeOfSections;
// kxld packs __TEXT_EXEC so we will do
// Note we align to at least 16-bytes as LDR's can scale up to 16 from their address
// and aligning them less than 16 would break that
uint32_t minAlignmentP2 = getMinAlignment(dylib.input->mappedFile.mh);
offsetInRegion = align(offsetInRegion, std::max(segInfo.p2align, 4U));
offsetInRegion = align(offsetInRegion, minAlignmentP2);
size_t copySize = std::min((size_t)segInfo.fileSize, (size_t)sizeOfSections);
uint64_t dstCacheSegmentSize = align(sizeOfSections, minAlignmentP2);
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)dstCacheSegmentSize;
loc.dstCacheFileSize = (uint32_t)copySize;
loc.copySegmentSize = (uint32_t)copySize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &readExecuteRegion;
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += loc.dstCacheSegmentSize;
});
}
// align r/x region end
readExecuteRegion.bufferSize = align(offsetInRegion, 14);
readExecuteRegion.sizeInUse = readExecuteRegion.bufferSize;
readExecuteRegion.initProt = VM_PROT_READ | VM_PROT_EXECUTE;
readExecuteRegion.maxProt = VM_PROT_READ | VM_PROT_EXECUTE;
readExecuteRegion.name = "__TEXT_EXEC";
}
if ( branchTargetsFromKexts != 0 ) {
// 6-bytes per jmpq
branchStubsRegion.bufferSize = align(branchTargetsFromKexts * 6, 14);
branchStubsRegion.sizeInUse = branchStubsRegion.bufferSize;
branchStubsRegion.initProt = VM_PROT_READ | VM_PROT_EXECUTE;
branchStubsRegion.maxProt = VM_PROT_READ | VM_PROT_EXECUTE;
branchStubsRegion.name = "__BRANCH_STUBS";
}
// __TEXT_BOOT_EXEC segments in xnu with r/x permissions
{
__block uint64_t offsetInRegion = 0;
for (AppCacheDylibInfo& dylib : sortedDylibs) {
bool canBePacked = dylib.input->mappedFile.mh->hasSplitSeg();
if (!canBePacked)
continue;
// Only do this for xnu
if ( !dylib.input->mappedFile.mh->isStaticExecutable() )
continue;
__block uint64_t textSegVmAddr = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( strcmp(segInfo.segName, "__TEXT_BOOT_EXEC") != 0 )
return;
if ( segInfo.protections != (VM_PROT_READ | VM_PROT_EXECUTE) )
return;
// We may have coalesced the sections at the end of this segment. In that case, shrink the segment to remove them.
__block size_t sizeOfSections = 0;
__block bool foundRemovedSection = false;
dylib.input->mappedFile.mh->forEachSection(^(const dyld3::MachOAnalyzer::SectionInfo §Info, bool malformedSectionRange, bool &stopSection) {
if (strcmp(sectInfo.segInfo.segName, segInfo.segName) != 0)
return;
if ( dylib._coalescer.sectionWasObliterated(segInfo.segName, sectInfo.sectName)) {
foundRemovedSection = true;
} else {
sizeOfSections = sectInfo.sectAddr + sectInfo.sectSize - segInfo.vmAddr;
}
});
if ( !foundRemovedSection )
sizeOfSections = segInfo.sizeOfSections;
// kxld packs __TEXT_EXEC so we will do
// Note we align to at least 16-bytes as LDR's can scale up to 16 from their address
// and aligning them less than 16 would break that
uint32_t minAlignmentP2 = getMinAlignment(dylib.input->mappedFile.mh);
offsetInRegion = align(offsetInRegion, std::max(segInfo.p2align, 4U));
offsetInRegion = align(offsetInRegion, minAlignmentP2);
size_t copySize = std::min((size_t)segInfo.fileSize, (size_t)sizeOfSections);
uint64_t dstCacheSegmentSize = align(sizeOfSections, minAlignmentP2);
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)dstCacheSegmentSize;
loc.dstCacheFileSize = (uint32_t)copySize;
loc.copySegmentSize = (uint32_t)copySize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &textBootExecRegion;
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += loc.dstCacheSegmentSize;
});
}
// align r/x region end
textBootExecRegion.bufferSize = align(offsetInRegion, 14);
textBootExecRegion.sizeInUse = textBootExecRegion.bufferSize;
textBootExecRegion.initProt = VM_PROT_READ | VM_PROT_EXECUTE;
textBootExecRegion.maxProt = VM_PROT_READ | VM_PROT_EXECUTE;
textBootExecRegion.name = "__TEXT_BOOT_EXEC";
}
// __DATA_CONST segments
{
__block uint64_t offsetInRegion = 0;
for (DylibInfo& dylib : sortedDylibs) {
if (!dylib.input->mappedFile.mh->hasSplitSeg())
continue;
__block uint64_t textSegVmAddr = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( (segInfo.protections & VM_PROT_EXECUTE) != 0 )
return;
if ( (strcmp(segInfo.segName, "__DATA_CONST") != 0)
&& (strcmp(segInfo.segName, "__PPLDATA_CONST") != 0)
&& (strcmp(segInfo.segName, "__LASTDATA_CONST") != 0) )
return;
if ( strcmp(segInfo.segName, "__LATE_CONST") == 0 )
return;
// kxld packs __DATA_CONST so we will do
uint32_t minAlignmentP2 = getMinAlignment(dylib.input->mappedFile.mh);
offsetInRegion = align(offsetInRegion, segInfo.p2align);
offsetInRegion = align(offsetInRegion, minAlignmentP2);
size_t copySize = std::min((size_t)segInfo.fileSize, (size_t)segInfo.sizeOfSections);
uint64_t dstCacheSegmentSize = align(segInfo.sizeOfSections, minAlignmentP2);
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)dstCacheSegmentSize;
loc.dstCacheFileSize = (uint32_t)copySize;
loc.copySegmentSize = (uint32_t)copySize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &dataConstRegion;
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += loc.dstCacheSegmentSize;
});
}
// align r/o region end
dataConstRegion.bufferSize = align(offsetInRegion, 14);
dataConstRegion.sizeInUse = dataConstRegion.bufferSize;
dataConstRegion.initProt = VM_PROT_READ;
dataConstRegion.maxProt = VM_PROT_READ;
dataConstRegion.name = "__DATA_CONST";
}
// __LATE_CONST segments
{
__block uint64_t offsetInRegion = 0;
for (DylibInfo& dylib : sortedDylibs) {
if (!dylib.input->mappedFile.mh->hasSplitSeg())
continue;
__block uint64_t textSegVmAddr = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( (segInfo.protections & VM_PROT_EXECUTE) != 0 )
return;
if ( (strcmp(segInfo.segName, "__LATE_CONST") != 0) )
return;
// pack __LATE_CONST
uint32_t minAlignmentP2 = getMinAlignment(dylib.input->mappedFile.mh);
offsetInRegion = align(offsetInRegion, segInfo.p2align);
offsetInRegion = align(offsetInRegion, minAlignmentP2);
size_t copySize = std::min((size_t)segInfo.fileSize, (size_t)segInfo.sizeOfSections);
uint64_t dstCacheSegmentSize = align(segInfo.sizeOfSections, minAlignmentP2);
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)dstCacheSegmentSize;
loc.dstCacheFileSize = (uint32_t)copySize;
loc.copySegmentSize = (uint32_t)copySize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &lateConstRegion;
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += loc.dstCacheSegmentSize;
});
}
// align r/o region end
lateConstRegion.bufferSize = align(offsetInRegion, 14);
lateConstRegion.sizeInUse = lateConstRegion.bufferSize;
lateConstRegion.initProt = VM_PROT_READ;
lateConstRegion.maxProt = VM_PROT_READ;
lateConstRegion.name = "__LATE_CONST";
}
// __DATA_SPTM segments
{
__block uint64_t offsetInRegion = 0;
for (DylibInfo& dylib : sortedDylibs) {
if (!dylib.input->mappedFile.mh->hasSplitSeg())
continue;
__block uint64_t textSegVmAddr = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( (segInfo.protections & VM_PROT_EXECUTE) != 0 )
return;
if ( (strcmp(segInfo.segName, "__DATA_SPTM") != 0) )
return;
uint32_t minAlignmentP2 = getMinAlignment(dylib.input->mappedFile.mh);
offsetInRegion = align(offsetInRegion, segInfo.p2align);
offsetInRegion = align(offsetInRegion, minAlignmentP2);
size_t copySize = std::min((size_t)segInfo.fileSize, (size_t)segInfo.sizeOfSections);
uint64_t dstCacheSegmentSize = align(segInfo.sizeOfSections, minAlignmentP2);
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)dstCacheSegmentSize;
loc.dstCacheFileSize = (uint32_t)copySize;
loc.copySegmentSize = (uint32_t)copySize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &dataSptmRegion;
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += loc.dstCacheSegmentSize;
});
}
// align r/o region end
dataSptmRegion.bufferSize = align(offsetInRegion, 14);
dataSptmRegion.sizeInUse = dataSptmRegion.bufferSize;
dataSptmRegion.initProt = VM_PROT_READ;
dataSptmRegion.maxProt = VM_PROT_READ;
dataSptmRegion.name = "__DATA_SPTM";
}
// Branch GOTs
if ( branchTargetsFromKexts != 0 ) {
// 8-bytes per GOT
branchGOTsRegion.bufferSize = align(branchTargetsFromKexts * 8, 14);
branchGOTsRegion.sizeInUse = branchGOTsRegion.bufferSize;
branchGOTsRegion.initProt = VM_PROT_READ | VM_PROT_WRITE;
branchGOTsRegion.maxProt = VM_PROT_READ | VM_PROT_WRITE;
branchGOTsRegion.name = "__BRANCH_GOTS";
}
// __DATA* segments
{
__block uint64_t offsetInRegion = 0;
for (DylibInfo& dylib : sortedDylibs) {
if (!dylib.input->mappedFile.mh->hasSplitSeg())
continue;
__block uint64_t textSegVmAddr = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( strcmp(segInfo.segName, "__HIB") == 0 )
return;
if ( (strcmp(segInfo.segName, "__DATA_CONST") == 0)
|| (strcmp(segInfo.segName, "__PPLDATA_CONST") == 0)
|| (strcmp(segInfo.segName, "__LASTDATA_CONST") == 0)
|| (strcmp(segInfo.segName, "__LATE_CONST") == 0) )
return;
if ( segInfo.protections != (VM_PROT_READ | VM_PROT_WRITE) )
return;
// kxld packs __DATA so we will do
uint32_t minAlignmentP2 = getMinAlignment(dylib.input->mappedFile.mh);
offsetInRegion = align(offsetInRegion, segInfo.p2align);
offsetInRegion = align(offsetInRegion, minAlignmentP2);
size_t copySize = std::min((size_t)segInfo.fileSize, (size_t)segInfo.sizeOfSections);
uint64_t dstCacheSegmentSize = align(segInfo.sizeOfSections, minAlignmentP2);
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)dstCacheSegmentSize;
loc.dstCacheFileSize = (uint32_t)copySize;
loc.copySegmentSize = (uint32_t)copySize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &readWriteRegion;
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += loc.dstCacheSegmentSize;
});
}
// align r/w region end
readWriteRegion.bufferSize = align(offsetInRegion, 14);
readWriteRegion.sizeInUse = readWriteRegion.bufferSize;
readWriteRegion.initProt = VM_PROT_READ | VM_PROT_WRITE;
readWriteRegion.maxProt = VM_PROT_READ | VM_PROT_WRITE;
readWriteRegion.name = "__DATA";
}
{
// Hibernate region
__block uint64_t offsetInRegion = 0;
for (DylibInfo& dylib : sortedDylibs) {
if ( !dylib.input->mappedFile.mh->isStaticExecutable() )
continue;
__block uint64_t textSegVmAddr = 0;
__block uint64_t hibernateAddress = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( strcmp(segInfo.segName, "__HIB") != 0 )
return;
size_t copySize = std::min((size_t)segInfo.fileSize, (size_t)segInfo.sizeOfSections);
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)segInfo.vmSize;
loc.dstCacheFileSize = (uint32_t)copySize;
loc.copySegmentSize = (uint32_t)copySize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &hibernateRegion;
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += loc.dstCacheSegmentSize;
hibernateAddress = segInfo.vmAddr;
});
if ( offsetInRegion != 0 ) {
// Pad out the VM offset so that the cache header starts where the base address
// really should be
uint64_t paddedSize = cacheBaseAddress - hibernateAddress;
if ( offsetInRegion > paddedSize ) {
_diagnostics.error("Could not lay out __HIB segment");
return;
}
offsetInRegion = paddedSize;
// Set the base address to the hibernate address so that we actually put the
// hibernate segment there
cacheBaseAddress = hibernateAddress;
}
// Only xnu has __HIB, so no need to continue once we've found it.
break;
}
hibernateRegion.bufferSize = align(offsetInRegion, 14);
hibernateRegion.sizeInUse = hibernateRegion.bufferSize;
hibernateRegion.initProt = VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
hibernateRegion.maxProt = VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
hibernateRegion.name = "__HIB";
}
// __TEXT and __DATA from non-split seg dylibs, if we have any
{
for (DylibInfo& dylib : sortedDylibs) {
bool canBePacked = dylib.input->mappedFile.mh->hasSplitSeg();
if (canBePacked)
continue;
__block uint64_t textSegVmAddr = 0;
dylib.input->mappedFile.mh->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegVmAddr = segInfo.vmAddr;
if ( strcmp(segInfo.segName, "__LINKEDIT") == 0 )
return;
nonSplitSegRegions.emplace_back();
nonSplitSegRegions.back().initProt = segInfo.protections;
nonSplitSegRegions.back().maxProt = segInfo.protections;
nonSplitSegRegions.back().name = "__REGION" + std::to_string(nonSplitSegRegions.size() - 1);
// Note we don't align the region offset as we have no split seg
uint64_t offsetInRegion = 0;
SegmentMappingInfo loc;
loc.srcSegment = (uint8_t*)dylib.input->mappedFile.mh + segInfo.vmAddr - textSegVmAddr;
loc.segName = segInfo.segName;
loc.dstSegment = nullptr;
loc.dstCacheUnslidAddress = offsetInRegion; // This will be updated later once we've assigned addresses
loc.dstCacheFileOffset = (uint32_t)offsetInRegion;
loc.dstCacheSegmentSize = (uint32_t)segInfo.vmSize;
loc.dstCacheFileSize = (uint32_t)segInfo.fileSize;
loc.copySegmentSize = (uint32_t)segInfo.fileSize;
loc.srcSegmentIndex = segInfo.segIndex;
loc.parentRegion = &nonSplitSegRegions.back();
dylib.cacheLocation[segInfo.segIndex] = loc;
offsetInRegion += loc.dstCacheSegmentSize;
// record non-split seg region end
nonSplitSegRegions.back().bufferSize = offsetInRegion;
nonSplitSegRegions.back().sizeInUse = nonSplitSegRegions.back().bufferSize;
});
}
}
// -sectcreate
if ( !customSegments.empty() ) {
for (CustomSegment& segment: customSegments) {
uint64_t offsetInRegion = 0;
for (CustomSegment::CustomSection& section : segment.sections) {
section.offsetInRegion = offsetInRegion;
offsetInRegion += section.data.size();
}
Region& customRegion = customDataRegions.emplace_back();
segment.parentRegion = &customRegion;
// align region end
customRegion.bufferSize = align(offsetInRegion, 14);
customRegion.sizeInUse = customRegion.bufferSize;
customRegion.initProt = VM_PROT_READ;
customRegion.maxProt = VM_PROT_READ;
customRegion.name = segment.segmentName;
}
}
// __PRELINK_INFO
{
// This is populated with regular kexts and codeless kexts
struct PrelinkInfo {
CFDictionaryRef infoPlist = nullptr;
const dyld3::MachOAnalyzer* ma = nullptr;
std::string_view bundlePath;
std::string_view executablePath;
};
std::vector<PrelinkInfo> infos;
for (AppCacheDylibInfo& dylib : sortedDylibs) {
if (dylib.infoPlist == nullptr)
continue;
infos.push_back({ dylib.infoPlist, dylib.input->mappedFile.mh, dylib.bundlePath, dylib.input->loadedFileInfo.path });
}
for (InputDylib& dylib : codelessKexts) {
infos.push_back({ dylib.infoPlist, nullptr, dylib.bundlePath, "" });
}
CFMutableArrayRef bundlesArrayRef = CFArrayCreateMutable(kCFAllocatorDefault, 0,
&kCFTypeArrayCallBacks);
for (PrelinkInfo& info : infos) {
CFDictionaryRef infoPlist = info.infoPlist;
// Create a copy of the dictionary so that we can add more fields
CFMutableDictionaryRef dictCopyRef = CFDictionaryCreateMutableCopy(kCFAllocatorDefault, 0, infoPlist);
// _PrelinkBundlePath
CFStringRef bundlePath = CFStringCreateWithCStringNoCopy(kCFAllocatorDefault, info.bundlePath.data(),
kCFStringEncodingASCII, kCFAllocatorNull);
CFDictionarySetValue(dictCopyRef, CFSTR("_PrelinkBundlePath"), bundlePath);
CFRelease(bundlePath);
// Note we want this address to be a large enough integer in the xml format that we have enough space
// to replace it with its real address later
const uint64_t largeAddress = 0x7FFFFFFFFFFFFFFF;
// _PrelinkExecutableLoadAddr
// Leave a placeholder for this for now just so that we have enough space for it later
CFNumberRef loadAddrRef = CFNumberCreate(kCFAllocatorDefault, kCFNumberLongLongType, &largeAddress);
CFDictionarySetValue(dictCopyRef, CFSTR("_PrelinkExecutableLoadAddr"), loadAddrRef);
CFRelease(loadAddrRef);
// _PrelinkExecutableRelativePath
if ( info.executablePath != "" ) {
const char* relativePath = info.executablePath.data();
if ( strncmp(relativePath, info.bundlePath.data(), info.bundlePath.size()) == 0 ) {
relativePath = relativePath + info.bundlePath.size();
if ( relativePath[0] == '/' )
++relativePath;
} else if ( const char* lastSlash = strrchr(relativePath, '/') )
relativePath = lastSlash+1;
CFStringRef executablePath = CFStringCreateWithCStringNoCopy(kCFAllocatorDefault, relativePath,
kCFStringEncodingASCII, kCFAllocatorNull);
CFDictionarySetValue(dictCopyRef, CFSTR("_PrelinkExecutableRelativePath"), executablePath);
CFRelease(executablePath);
}
// _PrelinkExecutableSize
// Use the size of the TEXT sections in the cache. This is required as we pack segments
__block uint64_t textSegSize = 0;
if ( info.ma != nullptr ) {
info.ma->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& segInfo, bool& stop) {
if ( strcmp(segInfo.segName, "__TEXT") == 0 )
textSegSize = segInfo.sizeOfSections == 0 ? segInfo.fileSize : segInfo.sizeOfSections;
});
}
if (textSegSize != 0) {