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dyld/dyld3/SharedCacheRuntime.cpp

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/*
* Copyright (c) 2017 Apple Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <sys/mman.h>
#include <mach/mach.h>
#include <mach-o/fat.h>
#include <mach-o/loader.h>
#include <mach-o/ldsyms.h>
#include <mach/shared_region.h>
#include <mach/mach.h>
#include <Availability.h>
#include <TargetConditionals.h>
#include "dyld_cache_format.h"
#include "SharedCacheRuntime.h"
#include "Loading.h"
#include "BootArgs.h"
#define ENABLE_DYLIBS_TO_OVERRIDE_CACHE_SIZE 1024
// should be in mach/shared_region.h
extern "C" int __shared_region_check_np(uint64_t* startaddress);
extern "C" int __shared_region_map_and_slide_np(int fd, uint32_t count, const shared_file_mapping_np mappings[], long slide, const dyld_cache_slide_info2* slideInfo, size_t slideInfoSize);
extern "C" int __shared_region_map_and_slide_2_np(uint32_t files_count, const shared_file_np files[], uint32_t mappings_count, const shared_file_mapping_slide_np mappings[]);
#ifndef VM_PROT_NOAUTH
#define VM_PROT_NOAUTH 0x40 /* must not interfere with normal prot assignments */
#endif
extern bool gEnableSharedCacheDataConst;
namespace dyld {
extern void log(const char*, ...);
extern void logToConsole(const char* format, ...);
#if defined(__x86_64__) && !TARGET_OS_SIMULATOR
bool isTranslated();
#endif
}
namespace dyld3 {
struct CacheInfo
{
shared_file_mapping_slide_np mappings[DyldSharedCache::MaxMappings];
uint32_t mappingsCount;
// All mappings come from the same file
int fd = 0;
uint64_t sharedRegionStart;
uint64_t sharedRegionSize;
uint64_t maxSlide;
};
#if __i386__
#define ARCH_NAME "i386"
#define ARCH_CACHE_MAGIC "dyld_v1 i386"
#elif __x86_64__
#define ARCH_NAME "x86_64"
#define ARCH_CACHE_MAGIC "dyld_v1 x86_64"
#define ARCH_NAME_H "x86_64h"
#define ARCH_CACHE_MAGIC_H "dyld_v1 x86_64h"
#elif __ARM_ARCH_7K__
#define ARCH_NAME "armv7k"
#define ARCH_CACHE_MAGIC "dyld_v1 armv7k"
#elif __ARM_ARCH_7A__
#define ARCH_NAME "armv7"
#define ARCH_CACHE_MAGIC "dyld_v1 armv7"
#elif __ARM_ARCH_7S__
#define ARCH_NAME "armv7s"
#define ARCH_CACHE_MAGIC "dyld_v1 armv7s"
#elif __arm64e__
#define ARCH_NAME "arm64e"
#define ARCH_CACHE_MAGIC "dyld_v1 arm64e"
#elif __arm64__
#if __LP64__
#define ARCH_NAME "arm64"
#define ARCH_CACHE_MAGIC "dyld_v1 arm64"
#else
#define ARCH_NAME "arm64_32"
#define ARCH_CACHE_MAGIC "dyld_v1arm64_32"
#endif
#endif
#if !TARGET_OS_SIMULATOR
static void rebaseChainV2(uint8_t* pageContent, uint16_t startOffset, uintptr_t slideAmount, const dyld_cache_slide_info2* slideInfo)
{
const uintptr_t deltaMask = (uintptr_t)(slideInfo->delta_mask);
const uintptr_t valueMask = ~deltaMask;
const uintptr_t valueAdd = (uintptr_t)(slideInfo->value_add);
const unsigned deltaShift = __builtin_ctzll(deltaMask) - 2;
uint32_t pageOffset = startOffset;
uint32_t delta = 1;
while ( delta != 0 ) {
uint8_t* loc = pageContent + pageOffset;
uintptr_t rawValue = *((uintptr_t*)loc);
delta = (uint32_t)((rawValue & deltaMask) >> deltaShift);
uintptr_t value = (rawValue & valueMask);
if ( value != 0 ) {
value += valueAdd;
value += slideAmount;
}
*((uintptr_t*)loc) = value;
//dyld::log(" pageOffset=0x%03X, loc=%p, org value=0x%08llX, new value=0x%08llX, delta=0x%X\n", pageOffset, loc, (uint64_t)rawValue, (uint64_t)value, delta);
pageOffset += delta;
}
}
#endif
#if !__LP64__ && !TARGET_OS_SIMULATOR
static void rebaseChainV4(uint8_t* pageContent, uint16_t startOffset, uintptr_t slideAmount, const dyld_cache_slide_info4* slideInfo)
{
const uintptr_t deltaMask = (uintptr_t)(slideInfo->delta_mask);
const uintptr_t valueMask = ~deltaMask;
const uintptr_t valueAdd = (uintptr_t)(slideInfo->value_add);
const unsigned deltaShift = __builtin_ctzll(deltaMask) - 2;
uint32_t pageOffset = startOffset;
uint32_t delta = 1;
while ( delta != 0 ) {
uint8_t* loc = pageContent + pageOffset;
uintptr_t rawValue = *((uintptr_t*)loc);
delta = (uint32_t)((rawValue & deltaMask) >> deltaShift);
uintptr_t value = (rawValue & valueMask);
if ( (value & 0xFFFF8000) == 0 ) {
// small positive non-pointer, use as-is
}
else if ( (value & 0x3FFF8000) == 0x3FFF8000 ) {
// small negative non-pointer
value |= 0xC0000000;
}
else {
value += valueAdd;
value += slideAmount;
}
*((uintptr_t*)loc) = value;
//dyld::log(" pageOffset=0x%03X, loc=%p, org value=0x%08llX, new value=0x%08llX, delta=0x%X\n", pageOffset, loc, (uint64_t)rawValue, (uint64_t)value, delta);
pageOffset += delta;
}
}
#endif
#if TARGET_OS_OSX
bool getMacOSCachePath(char pathBuffer[], size_t pathBufferSize,
const char* cacheDir, bool useHaswell) {
// Clear old attempts at finding a cache, if any
pathBuffer[0] = '\0';
// set cache dir
strlcpy(pathBuffer, cacheDir, pathBufferSize);
// append file component of cache file
if ( pathBuffer[strlen(pathBuffer)-1] != '/' )
strlcat(pathBuffer, "/", pathBufferSize);
#if __x86_64__
if ( useHaswell ) {
size_t len = strlen(pathBuffer);
struct stat haswellStatBuf;
strlcat(pathBuffer, DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME_H, pathBufferSize);
if ( dyld3::stat(pathBuffer, &haswellStatBuf) == 0 )
return true;
// no haswell cache file, use regular x86_64 cache
pathBuffer[len] = '\0';
}
#endif
struct stat statBuf;
strlcat(pathBuffer, DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME, pathBufferSize);
if ( dyld3::stat(pathBuffer, &statBuf) == 0 )
return true;
return false;
}
#endif // TARGET_OS_OSX
static void getCachePath(const SharedCacheOptions& options, size_t pathBufferSize, char pathBuffer[])
{
#if TARGET_OS_OSX
if ( options.cacheDirOverride != nullptr ) {
getMacOSCachePath(pathBuffer, pathBufferSize, options.cacheDirOverride, options.useHaswell);
} else {
getMacOSCachePath(pathBuffer, pathBufferSize, MACOSX_MRM_DYLD_SHARED_CACHE_DIR, options.useHaswell);
}
#else // TARGET_OS_OSX
// Non-macOS path
if ( options.cacheDirOverride != nullptr ) {
strlcpy(pathBuffer, options.cacheDirOverride, pathBufferSize);
} else {
strlcpy(pathBuffer, IPHONE_DYLD_SHARED_CACHE_DIR, sizeof(IPHONE_DYLD_SHARED_CACHE_DIR));
}
// append file component of cache file
if ( pathBuffer[strlen(pathBuffer)-1] != '/' )
strlcat(pathBuffer, "/", pathBufferSize);
strlcat(pathBuffer, DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME, pathBufferSize);
#if TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR
// use .development cache if it exists
if ( BootArgs::forceCustomerCache() ) {
// The boot-arg always wins. Use the customer cache if we are told to
return;
}
if ( !dyld3::internalInstall() ) {
// We can't use the development cache on customer installs
return;
}
if ( BootArgs::forceDevelopmentCache() ) {
// The boot-arg always wins. Use the development cache if we are told to
strlcat(pathBuffer, DYLD_SHARED_CACHE_DEVELOPMENT_EXT, pathBufferSize);
return;
}
// If only one or the other caches exists, then use the one we have
struct stat devCacheStatBuf;
struct stat optCacheStatBuf;
bool devCacheExists = (dyld3::stat(IPHONE_DYLD_SHARED_CACHE_DIR DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME DYLD_SHARED_CACHE_DEVELOPMENT_EXT, &devCacheStatBuf) == 0);
bool optCacheExists = (dyld3::stat(IPHONE_DYLD_SHARED_CACHE_DIR DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME, &optCacheStatBuf) == 0);
if ( !devCacheExists ) {
// If the dev cache doesn't exist, then use the customer cache
return;
}
if ( !optCacheExists ) {
// If the customer cache doesn't exist, then use the development cache
strlcat(pathBuffer, DYLD_SHARED_CACHE_DEVELOPMENT_EXT, pathBufferSize);
return;
}
// Finally, check for the sentinels
struct stat enableStatBuf;
//struct stat sentinelStatBuf;
bool enableFileExists = (dyld3::stat(IPHONE_DYLD_SHARED_CACHE_DIR "enable-dylibs-to-override-cache", &enableStatBuf) == 0);
// FIXME: rdar://problem/59813537 Re-enable once automation is updated to use boot-arg
bool sentinelFileExists = false;
//bool sentinelFileExists = (dyld3::stat(MACOSX_MRM_DYLD_SHARED_CACHE_DIR "enable_development_mode", &sentinelStatBuf) == 0);
if ( enableFileExists && (enableStatBuf.st_size < ENABLE_DYLIBS_TO_OVERRIDE_CACHE_SIZE) ) {
// if the old enable file exists, use the development cache
strlcat(pathBuffer, DYLD_SHARED_CACHE_DEVELOPMENT_EXT, pathBufferSize);
return;
}
if ( sentinelFileExists ) {
// If the new sentinel exists, then use the development cache
strlcat(pathBuffer, DYLD_SHARED_CACHE_DEVELOPMENT_EXT, pathBufferSize);
return;
}
#endif
#endif //!TARGET_OS_OSX
}
int openSharedCacheFile(const SharedCacheOptions& options, SharedCacheLoadInfo* results)
{
getCachePath(options, sizeof(results->path), results->path);
return dyld3::open(results->path, O_RDONLY, 0);
}
static bool validMagic(const SharedCacheOptions& options, const DyldSharedCache* cache)
{
if ( strcmp(cache->header.magic, ARCH_CACHE_MAGIC) == 0 )
return true;
#if __x86_64__
if ( options.useHaswell ) {
if ( strcmp(cache->header.magic, ARCH_CACHE_MAGIC_H) == 0 )
return true;
}
#endif
return false;
}
static bool validPlatform(const SharedCacheOptions& options, const DyldSharedCache* cache)
{
// grandfather in old cache that does not have platform in header
if ( cache->header.mappingOffset < 0xE0 )
return true;
if ( cache->header.platform != (uint32_t)MachOFile::currentPlatform() )
return false;
#if TARGET_OS_SIMULATOR
if ( cache->header.simulator == 0 )
return false;
#else
if ( cache->header.simulator != 0 )
return false;
#endif
return true;
}
#if !TARGET_OS_SIMULATOR
static void verboseSharedCacheMappings(const shared_file_mapping_slide_np mappings[DyldSharedCache::MaxMappings],
uint32_t mappingsCount)
{
for (int i=0; i < mappingsCount; ++i) {
const char* mappingName = "";
if ( mappings[i].sms_max_prot & VM_PROT_WRITE ) {
if ( mappings[i].sms_max_prot & VM_PROT_NOAUTH ) {
// __DATA*
mappingName = "data";
} else {
// __AUTH*
mappingName = "auth";
}
}
uint32_t init_prot = mappings[i].sms_init_prot & (VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE);
uint32_t max_prot = mappings[i].sms_max_prot & (VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE);
dyld::log(" 0x%08llX->0x%08llX init=%x, max=%x %s%s%s%s\n",
mappings[i].sms_address, mappings[i].sms_address+mappings[i].sms_size-1,
init_prot, max_prot,
((mappings[i].sms_init_prot & VM_PROT_READ) ? "read " : ""),
((mappings[i].sms_init_prot & VM_PROT_WRITE) ? "write " : ""),
((mappings[i].sms_init_prot & VM_PROT_EXECUTE) ? "execute " : ""),
mappingName);
}
}
static void verboseSharedCacheMappingsToConsole(const shared_file_mapping_slide_np mappings[DyldSharedCache::MaxMappings],
uint32_t mappingsCount)
{
for (int i=0; i < mappingsCount; ++i) {
const char* mappingName = "";
if ( mappings[i].sms_max_prot & VM_PROT_WRITE ) {
if ( mappings[i].sms_max_prot & VM_PROT_NOAUTH ) {
// __DATA*
mappingName = "data";
} else {
// __AUTH*
mappingName = "auth";
}
}
uint32_t init_prot = mappings[i].sms_init_prot & (VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE);
uint32_t max_prot = mappings[i].sms_max_prot & (VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE);
dyld::logToConsole("dyld: mapping 0x%08llX->0x%08llX init=%x, max=%x %s%s%s%s\n",
mappings[i].sms_address, mappings[i].sms_address+mappings[i].sms_size-1,
init_prot, max_prot,
((mappings[i].sms_init_prot & VM_PROT_READ) ? "read " : ""),
((mappings[i].sms_init_prot & VM_PROT_WRITE) ? "write " : ""),
((mappings[i].sms_init_prot & VM_PROT_EXECUTE) ? "execute " : ""),
mappingName);
}
}
#endif
static bool preflightCacheFile(const SharedCacheOptions& options, SharedCacheLoadInfo* results, CacheInfo* info)
{
// find and open shared cache file
int fd = openSharedCacheFile(options, results);
if ( fd == -1 ) {
results->errorMessage = "shared cache file open() failed";
return false;
}
struct stat cacheStatBuf;
if ( dyld3::stat(results->path, &cacheStatBuf) != 0 ) {
results->errorMessage = "shared cache file stat() failed";
::close(fd);
return false;
}
size_t cacheFileLength = (size_t)(cacheStatBuf.st_size);
// sanity check header and mappings
uint8_t firstPage[0x4000];
if ( ::pread(fd, firstPage, sizeof(firstPage), 0) != sizeof(firstPage) ) {
results->errorMessage = "shared cache file pread() failed";
::close(fd);
return false;
}
const DyldSharedCache* cache = (DyldSharedCache*)firstPage;
if ( !validMagic(options, cache) ) {
results->errorMessage = "shared cache file has wrong magic";
::close(fd);
return false;
}
if ( !validPlatform(options, cache) ) {
results->errorMessage = "shared cache file is for a different platform";
::close(fd);
return false;
}
if ( (cache->header.mappingCount < 3) || (cache->header.mappingCount > DyldSharedCache::MaxMappings) || (cache->header.mappingOffset > 0x168) ) {
results->errorMessage = "shared cache file mappings are invalid";
::close(fd);
return false;
}
const dyld_cache_mapping_info* const fileMappings = (dyld_cache_mapping_info*)&firstPage[cache->header.mappingOffset];
const dyld_cache_mapping_info* textMapping = &fileMappings[0];
const dyld_cache_mapping_info* firstDataMapping = &fileMappings[1];
const dyld_cache_mapping_info* linkeditMapping = &fileMappings[cache->header.mappingCount - 1];
if ( (textMapping->fileOffset != 0)
|| ((fileMappings[0].address + fileMappings[0].size) > firstDataMapping->address)
|| ((fileMappings[0].fileOffset + fileMappings[0].size) != firstDataMapping->fileOffset)
|| ((cache->header.codeSignatureOffset + cache->header.codeSignatureSize) != cacheFileLength)
|| (textMapping->maxProt != (VM_PROT_READ|VM_PROT_EXECUTE))
|| (linkeditMapping->maxProt != VM_PROT_READ) ) {
results->errorMessage = "shared cache text/linkedit mappings are invalid";
::close(fd);
return false;
}
// Check the __DATA mappings
for (unsigned i = 1; i != (cache->header.mappingCount - 1); ++i) {
if ( ((fileMappings[i].address + fileMappings[i].size) > fileMappings[i + 1].address)
|| ((fileMappings[i].fileOffset + fileMappings[i].size) != fileMappings[i + 1].fileOffset)
|| (fileMappings[i].maxProt != (VM_PROT_READ|VM_PROT_WRITE)) ) {
results->errorMessage = "shared cache data mappings are invalid";
::close(fd);
return false;
}
}
if ( (textMapping->address != cache->header.sharedRegionStart) || ((linkeditMapping->address + linkeditMapping->size) > (cache->header.sharedRegionStart+cache->header.sharedRegionSize)) ) {
results->errorMessage = "shared cache file mapping addressses invalid";
::close(fd);
return false;
}
// register code signature of cache file
fsignatures_t siginfo;
siginfo.fs_file_start = 0; // cache always starts at beginning of file
siginfo.fs_blob_start = (void*)cache->header.codeSignatureOffset;
siginfo.fs_blob_size = (size_t)(cache->header.codeSignatureSize);
int result = fcntl(fd, F_ADDFILESIGS_RETURN, &siginfo);
if ( result == -1 ) {
results->errorMessage = "code signature registration for shared cache failed";
::close(fd);
return false;
}
// <rdar://problem/23188073> validate code signature covers entire shared cache
uint64_t codeSignedLength = siginfo.fs_file_start;
if ( codeSignedLength < cache->header.codeSignatureOffset ) {
results->errorMessage = "code signature does not cover entire shared cache file";
::close(fd);
return false;
}
void* mappedData = ::mmap(NULL, sizeof(firstPage), PROT_READ|PROT_EXEC, MAP_PRIVATE, fd, 0);
if ( mappedData == MAP_FAILED ) {
results->errorMessage = "first page of shared cache not mmap()able";
::close(fd);
return false;
}
if ( memcmp(mappedData, firstPage, sizeof(firstPage)) != 0 ) {
results->errorMessage = "first page of mmap()ed shared cache not valid";
::close(fd);
return false;
}
::munmap(mappedData, sizeof(firstPage));
// fill out results
info->mappingsCount = cache->header.mappingCount;
// We have to emit the mapping for the __LINKEDIT before the slid mappings
// This is so that the kernel has already mapped __LINKEDIT in to its address space
// for when it copies the slid info for each __DATA mapping
for (int i=0; i < cache->header.mappingCount; ++i) {
uint64_t slideInfoFileOffset = 0;
uint64_t slideInfoFileSize = 0;
vm_prot_t authProt = 0;
vm_prot_t initProt = fileMappings[i].initProt;
if ( cache->header.mappingOffset <= __offsetof(dyld_cache_header, mappingWithSlideOffset) ) {
// Old cache without the new slid mappings
if ( i == 1 ) {
// Add slide info to the __DATA mapping
slideInfoFileOffset = cache->header.slideInfoOffsetUnused;
slideInfoFileSize = cache->header.slideInfoSizeUnused;
// Don't set auth prot to anything interseting on the old mapppings
authProt = 0;
}
} else {
// New cache where each mapping has a corresponding slid mapping
const dyld_cache_mapping_and_slide_info* slidableMappings = (const dyld_cache_mapping_and_slide_info*)&firstPage[cache->header.mappingWithSlideOffset];
slideInfoFileOffset = slidableMappings[i].slideInfoFileOffset;
slideInfoFileSize = slidableMappings[i].slideInfoFileSize;
if ( (slidableMappings[i].flags & DYLD_CACHE_MAPPING_AUTH_DATA) == 0 )
authProt = VM_PROT_NOAUTH;
if ( (slidableMappings[i].flags & DYLD_CACHE_MAPPING_CONST_DATA) != 0 ) {
// The cache was built with __DATA_CONST being read-only. We can override that
// with a boot-arg
if ( !gEnableSharedCacheDataConst )
initProt |= VM_PROT_WRITE;
}
}
// Add a file for each mapping
info->fd = fd;
info->mappings[i].sms_address = fileMappings[i].address;
info->mappings[i].sms_size = fileMappings[i].size;
info->mappings[i].sms_file_offset = fileMappings[i].fileOffset;
info->mappings[i].sms_slide_size = 0;
info->mappings[i].sms_slide_start = 0;
info->mappings[i].sms_max_prot = fileMappings[i].maxProt;
info->mappings[i].sms_init_prot = initProt;
if ( slideInfoFileSize != 0 ) {
uint64_t offsetInLinkEditRegion = (slideInfoFileOffset - linkeditMapping->fileOffset);
info->mappings[i].sms_slide_start = (user_addr_t)(linkeditMapping->address + offsetInLinkEditRegion);
info->mappings[i].sms_slide_size = (user_addr_t)slideInfoFileSize;
info->mappings[i].sms_init_prot |= (VM_PROT_SLIDE | authProt);
info->mappings[i].sms_max_prot |= (VM_PROT_SLIDE | authProt);
}
}
info->sharedRegionStart = cache->header.sharedRegionStart;
info->sharedRegionSize = cache->header.sharedRegionSize;
info->maxSlide = cache->header.maxSlide;
return true;
}
#if !TARGET_OS_SIMULATOR
// update all __DATA pages with slide info
static bool rebaseDataPages(bool isVerbose, const dyld_cache_slide_info* slideInfo, const uint8_t *dataPagesStart,
uint64_t sharedRegionStart, SharedCacheLoadInfo* results)
{
const dyld_cache_slide_info* slideInfoHeader = slideInfo;
if ( slideInfoHeader != nullptr ) {
if ( slideInfoHeader->version == 2 ) {
const dyld_cache_slide_info2* slideHeader = (dyld_cache_slide_info2*)slideInfo;
const uint32_t page_size = slideHeader->page_size;
const uint16_t* page_starts = (uint16_t*)((long)(slideInfo) + slideHeader->page_starts_offset);
const uint16_t* page_extras = (uint16_t*)((long)(slideInfo) + slideHeader->page_extras_offset);
for (int i=0; i < slideHeader->page_starts_count; ++i) {
uint8_t* page = (uint8_t*)(long)(dataPagesStart + (page_size*i));
uint16_t pageEntry = page_starts[i];
//dyld::log("page[%d]: page_starts[i]=0x%04X\n", i, pageEntry);
if ( pageEntry == DYLD_CACHE_SLIDE_PAGE_ATTR_NO_REBASE )
continue;
if ( pageEntry & DYLD_CACHE_SLIDE_PAGE_ATTR_EXTRA ) {
uint16_t chainIndex = (pageEntry & 0x3FFF);
bool done = false;
while ( !done ) {
uint16_t pInfo = page_extras[chainIndex];
uint16_t pageStartOffset = (pInfo & 0x3FFF)*4;
//dyld::log(" chain[%d] pageOffset=0x%03X\n", chainIndex, pageStartOffset);
rebaseChainV2(page, pageStartOffset, results->slide, slideHeader);
done = (pInfo & DYLD_CACHE_SLIDE_PAGE_ATTR_END);
++chainIndex;
}
}
else {
uint32_t pageOffset = pageEntry * 4;
//dyld::log(" start pageOffset=0x%03X\n", pageOffset);
rebaseChainV2(page, pageOffset, results->slide, slideHeader);
}
}
}
#if __LP64__
else if ( slideInfoHeader->version == 3 ) {
const dyld_cache_slide_info3* slideHeader = (dyld_cache_slide_info3*)slideInfo;
const uint32_t pageSize = slideHeader->page_size;
for (int i=0; i < slideHeader->page_starts_count; ++i) {
uint8_t* page = (uint8_t*)(dataPagesStart + (pageSize*i));
uint64_t delta = slideHeader->page_starts[i];
//dyld::log("page[%d]: page_starts[i]=0x%04X\n", i, delta);
if ( delta == DYLD_CACHE_SLIDE_V3_PAGE_ATTR_NO_REBASE )
continue;
delta = delta/sizeof(uint64_t); // initial offset is byte based
dyld_cache_slide_pointer3* loc = (dyld_cache_slide_pointer3*)page;
do {
loc += delta;
delta = loc->plain.offsetToNextPointer;
if ( loc->auth.authenticated ) {
#if __has_feature(ptrauth_calls)
uint64_t target = sharedRegionStart + loc->auth.offsetFromSharedCacheBase + results->slide;
MachOLoaded::ChainedFixupPointerOnDisk ptr;
ptr.raw64 = *((uint64_t*)loc);
loc->raw = ptr.arm64e.signPointer(loc, target);
#else
results->errorMessage = "invalid pointer kind in cache file";
return false;
#endif
}
else {
MachOLoaded::ChainedFixupPointerOnDisk ptr;
ptr.raw64 = *((uint64_t*)loc);
loc->raw = ptr.arm64e.unpackTarget() + results->slide;
}
} while (delta != 0);
}
}
#else
else if ( slideInfoHeader->version == 4 ) {
const dyld_cache_slide_info4* slideHeader = (dyld_cache_slide_info4*)slideInfo;
const uint32_t page_size = slideHeader->page_size;
const uint16_t* page_starts = (uint16_t*)((long)(slideInfo) + slideHeader->page_starts_offset);
const uint16_t* page_extras = (uint16_t*)((long)(slideInfo) + slideHeader->page_extras_offset);
for (int i=0; i < slideHeader->page_starts_count; ++i) {
uint8_t* page = (uint8_t*)(long)(dataPagesStart + (page_size*i));
uint16_t pageEntry = page_starts[i];
//dyld::log("page[%d]: page_starts[i]=0x%04X\n", i, pageEntry);
if ( pageEntry == DYLD_CACHE_SLIDE4_PAGE_NO_REBASE )
continue;
if ( pageEntry & DYLD_CACHE_SLIDE4_PAGE_USE_EXTRA ) {
uint16_t chainIndex = (pageEntry & DYLD_CACHE_SLIDE4_PAGE_INDEX);
bool done = false;
while ( !done ) {
uint16_t pInfo = page_extras[chainIndex];
uint16_t pageStartOffset = (pInfo & DYLD_CACHE_SLIDE4_PAGE_INDEX)*4;
//dyld::log(" chain[%d] pageOffset=0x%03X\n", chainIndex, pageStartOffset);
rebaseChainV4(page, pageStartOffset, results->slide, slideHeader);
done = (pInfo & DYLD_CACHE_SLIDE4_PAGE_EXTRA_END);
++chainIndex;
}
}
else {
uint32_t pageOffset = pageEntry * 4;
//dyld::log(" start pageOffset=0x%03X\n", pageOffset);
rebaseChainV4(page, pageOffset, results->slide, slideHeader);
}
}
}
#endif // LP64
else {
results->errorMessage = "invalid slide info in cache file";
return false;
}
}
return true;
}
static bool reuseExistingCache(const SharedCacheOptions& options, SharedCacheLoadInfo* results)
{
uint64_t cacheBaseAddress;
#if __i386__
if ( syscall(294, &cacheBaseAddress) == 0 ) {
#else
if ( __shared_region_check_np(&cacheBaseAddress) == 0 ) {
#endif
const DyldSharedCache* existingCache = (DyldSharedCache*)cacheBaseAddress;
if ( validMagic(options, existingCache) ) {
const dyld_cache_mapping_info* const fileMappings = (dyld_cache_mapping_info*)(cacheBaseAddress + existingCache->header.mappingOffset);
results->loadAddress = existingCache;
results->slide = (long)(cacheBaseAddress - fileMappings[0].address);
// we don't know the path this cache was previously loaded from, assume default
getCachePath(options, sizeof(results->path), results->path);
if ( options.verbose ) {
const dyld_cache_mapping_and_slide_info* const mappings = (const dyld_cache_mapping_and_slide_info*)(cacheBaseAddress + existingCache->header.mappingWithSlideOffset);
dyld::log("re-using existing shared cache (%s):\n", results->path);
shared_file_mapping_slide_np slidMappings[DyldSharedCache::MaxMappings];
for (int i=0; i < DyldSharedCache::MaxMappings; ++i) {
slidMappings[i].sms_address = mappings[i].address;
slidMappings[i].sms_size = mappings[i].size;
slidMappings[i].sms_file_offset = mappings[i].fileOffset;
slidMappings[i].sms_max_prot = mappings[i].maxProt;
slidMappings[i].sms_init_prot = mappings[i].initProt;
slidMappings[i].sms_address += results->slide;
if ( existingCache->header.mappingOffset > __offsetof(dyld_cache_header, mappingWithSlideOffset) ) {
// New caches have slide info on each new mapping
const dyld_cache_mapping_and_slide_info* const slidableMappings = (dyld_cache_mapping_and_slide_info*)(cacheBaseAddress + existingCache->header.mappingWithSlideOffset);
assert(existingCache->header.mappingWithSlideCount <= DyldSharedCache::MaxMappings);
if ( !(slidableMappings[i].flags & DYLD_CACHE_MAPPING_AUTH_DATA) ) {
slidMappings[i].sms_max_prot |= VM_PROT_NOAUTH;
slidMappings[i].sms_init_prot |= VM_PROT_NOAUTH;
}
if ( (slidableMappings[i].flags & DYLD_CACHE_MAPPING_CONST_DATA) != 0 ) {
// The cache was built with __DATA_CONST being read-only. We can override that
// with a boot-arg
if ( !gEnableSharedCacheDataConst )
slidMappings[i].sms_init_prot |= VM_PROT_WRITE;
}
}
}
verboseSharedCacheMappings(slidMappings, existingCache->header.mappingCount);
}
}
else {
results->errorMessage = "existing shared cache in memory is not compatible";
}
return true;
}
return false;
}
static long pickCacheASLRSlide(CacheInfo& info)
{
// choose new random slide
#if TARGET_OS_IPHONE || (TARGET_OS_OSX && TARGET_CPU_ARM64)
// <rdar://problem/20848977> change shared cache slide for 32-bit arm to always be 16k aligned
long slide;
if (info.maxSlide == 0)
slide = 0;
else
slide = ((arc4random() % info.maxSlide) & (-16384));
#else
long slide;
if (info.maxSlide == 0)
slide = 0;
else
slide = ((arc4random() % info.maxSlide) & (-4096));
#if defined(__x86_64__) && !TARGET_OS_SIMULATOR
if (dyld::isTranslated()) {
slide &= (-16384);
}
#endif
#endif
return slide;
}
static bool mapCacheSystemWide(const SharedCacheOptions& options, SharedCacheLoadInfo* results)
{
CacheInfo info;
if ( !preflightCacheFile(options, results, &info) )
return false;
int result = 0;
if ( info.mappingsCount != 3 ) {
uint32_t maxSlide = options.disableASLR ? 0 : (uint32_t)info.maxSlide;
shared_file_np file;
file.sf_fd = info.fd;
file.sf_mappings_count = info.mappingsCount;
// For the new syscall, this is actually the max slide. The kernel now owns the actual slide
file.sf_slide = maxSlide;
result = __shared_region_map_and_slide_2_np(1, &file, info.mappingsCount, info.mappings);
} else {
// With the old syscall, dyld has to choose the slide
results->slide = options.disableASLR ? 0 : pickCacheASLRSlide(info);
// update mappings based on the slide we choose
for (uint32_t i=0; i < info.mappingsCount; ++i) {
info.mappings[i].sms_address += results->slide;
if ( info.mappings[i].sms_slide_size != 0 )
info.mappings[i].sms_slide_start += (uint32_t)results->slide;
}
// If we get here then we don't have the new kernel function, so use the old one
const dyld_cache_slide_info2* slideInfo = nullptr;
size_t slideInfoSize = 0;
shared_file_mapping_np mappings[3];
for (unsigned i = 0; i != 3; ++i) {
mappings[i].sfm_address = info.mappings[i].sms_address;
mappings[i].sfm_size = info.mappings[i].sms_size;
mappings[i].sfm_file_offset = info.mappings[i].sms_file_offset;
mappings[i].sfm_max_prot = info.mappings[i].sms_max_prot;
mappings[i].sfm_init_prot = info.mappings[i].sms_init_prot;
if ( info.mappings[i].sms_slide_size != 0 ) {
slideInfo = (dyld_cache_slide_info2*)info.mappings[i].sms_slide_start;
slideInfoSize = (size_t)info.mappings[i].sms_slide_size;
}
}
result = __shared_region_map_and_slide_np(info.fd, 3, mappings, results->slide, slideInfo, slideInfoSize);
}
::close(info.fd);
if ( result == 0 ) {
results->loadAddress = (const DyldSharedCache*)(info.mappings[0].sms_address);
if ( info.mappingsCount != 3 ) {
// We don't know our own slide any more as the kernel owns it, so ask for it again now
if ( reuseExistingCache(options, results) ) {
// update mappings based on the slide the kernel chose
for (uint32_t i=0; i < info.mappingsCount; ++i) {
info.mappings[i].sms_address += results->slide;
if ( info.mappings[i].sms_slide_size != 0 )
info.mappings[i].sms_slide_start += (uint32_t)results->slide;
}
if ( options.verbose )
verboseSharedCacheMappingsToConsole(info.mappings, info.mappingsCount);
return true;
}
// Uh oh, we mapped the kernel, but we didn't find the slide
if ( options.verbose )
dyld::logToConsole("dyld: error finding shared cache slide for system wide mapping\n");
return false;
}
}
else {
// could be another process beat us to it
if ( reuseExistingCache(options, results) )
return true;
// if cache does not exist, then really is an error
if ( results->errorMessage == nullptr )
results->errorMessage = "syscall to map cache into shared region failed";
return false;
}
if ( options.verbose ) {
dyld::log("mapped dyld cache file system wide: %s\n", results->path);
verboseSharedCacheMappings(info.mappings, info.mappingsCount);
}
return true;
}
#endif // TARGET_OS_SIMULATOR
static bool mapCachePrivate(const SharedCacheOptions& options, SharedCacheLoadInfo* results)
{
// open and validate cache file
CacheInfo info;
if ( !preflightCacheFile(options, results, &info) )
return false;
// compute ALSR slide
results->slide = 0;
#if !TARGET_OS_SIMULATOR
results->slide = options.disableASLR ? 0 : pickCacheASLRSlide(info);
#endif
// update mappings
for (uint32_t i=0; i < info.mappingsCount; ++i) {
info.mappings[i].sms_address += (uint32_t)results->slide;
if ( info.mappings[i].sms_slide_size != 0 )
info.mappings[i].sms_slide_start += (uint32_t)results->slide;
}
results->loadAddress = (const DyldSharedCache*)(info.mappings[0].sms_address);
// deallocate any existing system wide shared cache
deallocateExistingSharedCache();
#if TARGET_OS_SIMULATOR && TARGET_OS_WATCH
// <rdar://problem/50887685> watchOS 32-bit cache does not overlap macOS dyld cache address range
// mmap() of a file needs a vm_allocation behind it, so make one
vm_address_t loadAddress = 0x40000000;
::vm_allocate(mach_task_self(), &loadAddress, 0x40000000, VM_FLAGS_FIXED);
#endif
// map cache just for this process with mmap()
for (int i=0; i < info.mappingsCount; ++i) {
void* mmapAddress = (void*)(uintptr_t)(info.mappings[i].sms_address);
size_t size = (size_t)(info.mappings[i].sms_size);
//dyld::log("dyld: mapping address %p with size 0x%08lX\n", mmapAddress, size);
int protection = 0;
if ( info.mappings[i].sms_init_prot & VM_PROT_EXECUTE )
protection |= PROT_EXEC;
if ( info.mappings[i].sms_init_prot & VM_PROT_READ )
protection |= PROT_READ;
if ( info.mappings[i].sms_init_prot & VM_PROT_WRITE )
protection |= PROT_WRITE;
off_t offset = info.mappings[i].sms_file_offset;
if ( ::mmap(mmapAddress, size, protection, MAP_FIXED | MAP_PRIVATE, info.fd, offset) != mmapAddress ) {
// failed to map some chunk of this shared cache file
// clear shared region
::mmap((void*)((long)SHARED_REGION_BASE), SHARED_REGION_SIZE, PROT_NONE, MAP_FIXED | MAP_PRIVATE| MAP_ANON, 0, 0);
// return failure
results->loadAddress = nullptr;
results->errorMessage = "could not mmap() part of dyld cache";
::close(info.fd);
return false;
}
}
::close(info.fd);
#if TARGET_OS_SIMULATOR // simulator caches do not support sliding
return true;
#else
// Change __DATA_CONST to read-write for this block
DyldSharedCache::DataConstScopedWriter patcher(results->loadAddress, mach_task_self(), options.verbose ? &dyld::log : nullptr);
__block bool success = true;
for (int i=0; i < info.mappingsCount; ++i) {
if ( info.mappings[i].sms_slide_size == 0 )
continue;
const dyld_cache_slide_info* slideInfoHeader = (const dyld_cache_slide_info*)info.mappings[i].sms_slide_start;
const uint8_t* mappingPagesStart = (const uint8_t*)info.mappings[i].sms_address;
success &= rebaseDataPages(options.verbose, slideInfoHeader, mappingPagesStart, info.sharedRegionStart, results);
}
if ( options.verbose ) {
dyld::log("mapped dyld cache file private to process (%s):\n", results->path);
verboseSharedCacheMappings(info.mappings, info.mappingsCount);
}
return success;
#endif
}
bool loadDyldCache(const SharedCacheOptions& options, SharedCacheLoadInfo* results)
{
results->loadAddress = 0;
results->slide = 0;
results->errorMessage = nullptr;
#if TARGET_OS_SIMULATOR
// simulator only supports mmap()ing cache privately into process
return mapCachePrivate(options, results);
#else
if ( options.forcePrivate ) {
// mmap cache into this process only
return mapCachePrivate(options, results);
}
else {
// fast path: when cache is already mapped into shared region
bool hasError = false;
if ( reuseExistingCache(options, results) ) {
hasError = (results->errorMessage != nullptr);
} else {
// slow path: this is first process to load cache
hasError = mapCacheSystemWide(options, results);
}
return hasError;
}
#endif
}
bool findInSharedCacheImage(const SharedCacheLoadInfo& loadInfo, const char* dylibPathToFind, SharedCacheFindDylibResults* results)
{
if ( loadInfo.loadAddress == nullptr )
return false;
if ( loadInfo.loadAddress->header.formatVersion != dyld3::closure::kFormatVersion ) {
// support for older cache with a different Image* format
#if TARGET_OS_IPHONE
uint64_t hash = 0;
for (const char* s=dylibPathToFind; *s != '\0'; ++s)
hash += hash*4 + *s;
#endif
const dyld_cache_image_info* const start = (dyld_cache_image_info*)((uint8_t*)loadInfo.loadAddress + loadInfo.loadAddress->header.imagesOffset);
const dyld_cache_image_info* const end = &start[loadInfo.loadAddress->header.imagesCount];
for (const dyld_cache_image_info* p = start; p != end; ++p) {
#if TARGET_OS_IPHONE
// on iOS, inode is used to hold hash of path
if ( (p->modTime == 0) && (p->inode != hash) )
continue;
#endif
const char* aPath = (char*)loadInfo.loadAddress + p->pathFileOffset;
if ( strcmp(aPath, dylibPathToFind) == 0 ) {
results->mhInCache = (const mach_header*)(p->address+loadInfo.slide);
results->pathInCache = aPath;
results->slideInCache = loadInfo.slide;
results->image = nullptr;
return true;
}
}
return false;
}
const dyld3::closure::ImageArray* images = loadInfo.loadAddress->cachedDylibsImageArray();
results->image = nullptr;
uint32_t imageIndex;
if ( loadInfo.loadAddress->hasImagePath(dylibPathToFind, imageIndex) ) {
results->image = images->imageForNum(imageIndex+1);
}
if ( results->image == nullptr )
return false;
results->mhInCache = (const mach_header*)((uintptr_t)loadInfo.loadAddress + results->image->cacheOffset());
results->pathInCache = results->image->path();
results->slideInCache = loadInfo.slide;
return true;
}
bool pathIsInSharedCacheImage(const SharedCacheLoadInfo& loadInfo, const char* dylibPathToFind)
{
if ( (loadInfo.loadAddress == nullptr) )
return false;
uint32_t imageIndex;
return loadInfo.loadAddress->hasImagePath(dylibPathToFind, imageIndex);
}
void deallocateExistingSharedCache()
{
#if TARGET_OS_SIMULATOR
// dyld deallocated macOS shared cache before jumping into dyld_sim
#else
// <rdar://problem/50773474> remove the shared region sub-map
uint64_t existingCacheAddress = 0;
if ( __shared_region_check_np(&existingCacheAddress) == 0 ) {
::mmap((void*)((long)SHARED_REGION_BASE), SHARED_REGION_SIZE, PROT_NONE, MAP_FIXED | MAP_PRIVATE| MAP_ANON, 0, 0);
}
#endif
}
} // namespace dyld3