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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 |