| /*␊ |
| * Copyright (c) 2009 Evan Lojewski. All rights reserved.␊ |
| *␊ |
| */␊ |
| ␊ |
| #include "libsaio.h"␊ |
| #include "kernel_patcher.h"␊ |
| ␊ |
| #define NUM_SYMBOLS␉␉3␊ |
| ␊ |
| #define SYMBOL_CPUID_SET_INFO␉␉␉␉0␊ |
| #define SYMBOL_PANIC␉␉␉␉␉␉1␊ |
| #define SYMBOL_PMCPUEXITHALTTOOFF␉␉␉2␊ |
| ␊ |
| #define SYMBOL_CPUID_SET_INFO_STRING␉␉"_cpuid_set_info"␊ |
| #define SYMBOL_PANIC_STRING␉␉␉␉␉"_panic"␊ |
| #define SYMBOL_PMCPUEXITHALTTOOFF_STRING␉"_pmCPUExitHaltToOff"␊ |
| ␊ |
| char* kernelSymbols[NUM_SYMBOLS] = {␊ |
| ␉SYMBOL_CPUID_SET_INFO_STRING,␊ |
| ␉SYMBOL_PANIC_STRING,␊ |
| ␉SYMBOL_PMCPUEXITHALTTOOFF_STRING␊ |
| };␊ |
| ␊ |
| UInt32 kernelSymbolAddresses[NUM_SYMBOLS] = {␊ |
| ␉0,␊ |
| ␉0,␊ |
| ␉0␊ |
| };␊ |
| ␊ |
| ␊ |
| UInt32 textSection;␊ |
| UInt32 textAddress;␊ |
| ␊ |
| ␊ |
| extern unsigned long gBinaryAddress;␊ |
| ␊ |
| ␊ |
| void patch_kernel()␊ |
| {␊ |
| ␉switch (locate_symbols((void*)gBinaryAddress)) {␊ |
| ␉␉case KERNEL_32:␊ |
| ␉␉␉patch_kernel_32((void*)gBinaryAddress);␊ |
| ␉␉␉break;␊ |
| ␉␉case KERNEL_64:␊ |
| ␉␉default:␊ |
| ␉␉␉patch_kernel_64((void*)gBinaryAddress);␊ |
| ␉␉␉break;␊ |
| ␉}␊ |
| }␊ |
| ␊ |
| // patches a 64bit kernel.␊ |
| void patch_kernel_64(void* kernelData)␊ |
| {␊ |
| ␉// At the moment, the kernel patching code fails when used␊ |
| ␉// in 64bit mode, so we don't patch it. This is due to 32bit vs 64bit␊ |
| ␉// pointers as well as changes in structure sizes␊ |
| ␉verbose("Unable to patch 64bit kernel. Please use arch=i386.\n");␊ |
| }␊ |
| ␊ |
| /**␊ |
| ** patch_kernel_32␊ |
| **␉␉Due to the way the _cpuid_set_info function is writtin, the first instance of _panic is called␊ |
| **␉␉␉when an unsupported (read: non apple used cpu) is found. This routine locates that first _panic call␊ |
| **␉␉␉and replaces the jump call (0xe8) with no ops (0x90).␊ |
| **/␊ |
| ␊ |
| void patch_kernel_32(void* kernelData)␊ |
| {␊ |
| ␉patch_pmCPUExitHaltToOff(kernelData);␊ |
| ␉patch_cpuid_set_info(kernelData);␊ |
| ␊ |
| }␊ |
| ␊ |
| /**␊ |
| **␉␉This functions located the following in the mach_kernel symbol table␊ |
| **␉␉␉_panic␊ |
| **␉␉␉_cpuid_set_info␊ |
| **/␊ |
| int locate_symbols(void* kernelData)␊ |
| {␊ |
| ␉UInt16 symbolIndexes[NUM_SYMBOLS];␊ |
| ␊ |
| ␉struct load_command *loadCommand;␊ |
| ␉struct symtab_command *symtableData;␊ |
| ␉struct nlist *symbolEntry;␊ |
| ␉␊ |
| ␉char* symbolString;␊ |
| ␊ |
| ␉UInt32 kernelIndex = 0;␊ |
| ␉kernelIndex += sizeof(struct mach_header);␊ |
| ␉␊ |
| ␉if(((struct mach_header*)kernelData)->magic != MH_MAGIC) return KERNEL_64;␊ |
| ␉␊ |
| ␉//printf("%d load commands beginning at 0x%X\n", (unsigned int)header->ncmds, (unsigned int)kernelIndex);␊ |
| ␉//printf("Commands take up %d bytes\n", header->sizeofcmds);␊ |
| ␉␊ |
| ␉␊ |
| ␉int cmd = 0;␊ |
| ␉while(cmd < ((struct mach_header*)kernelData)->ncmds)␉// TODO: for loop instead␊ |
| ␉{␊ |
| ␉␉cmd++;␊ |
| ␉␉␊ |
| ␉␉loadCommand = kernelData + kernelIndex;␊ |
| ␉␉␊ |
| ␉␉UInt cmdSize = loadCommand->cmdsize;␊ |
| ␉␉␊ |
| ␉␉␊ |
| ␉␉// Locate start of _panic and _cpuid_set_info in the symbol tabe.␊ |
| ␉␉// Load commands should be anded with 0x7FFFFFFF to ignore the␉LC_REQ_DYLD flag␊ |
| ␉␉if((loadCommand->cmd & 0x7FFFFFFF) == LC_SYMTAB)␉␉// We only care about the symtab segment␊ |
| ␉␉{␊ |
| ␉␉␉//printf("Located symtable, length is 0x%X, 0x%X\n", (unsigned int)loadCommand->cmdsize, (unsigned int)sizeof(symtableData));␊ |
| ␉␉␉␊ |
| ␉␉␉symtableData = kernelData + kernelIndex;␊ |
| ␉␉␉kernelIndex += sizeof(struct symtab_command);␊ |
| ␉␉␉␊ |
| ␉␉␉cmdSize -= sizeof(struct symtab_command);␊ |
| ␊ |
| ␉␉␉// Loop through symbol table untill all of the symbols have been found␊ |
| ␉␉␉␊ |
| ␉␉␉symbolString = kernelData + symtableData->stroff; ␊ |
| ␉␉␉␊ |
| ␉␉␉␊ |
| ␉␉␉UInt16 symbolIndex = 0;␊ |
| ␉␉␉UInt8 numSymbolsFound = 0;␊ |
| ␊ |
| ␉␉␉while(symbolIndex < symtableData->nsyms && numSymbolsFound < NUM_SYMBOLS)␉// TODO: for loop␊ |
| ␉␉␉{␊ |
| ␉␉␉␉int i = 0;␊ |
| ␉␉␉␉while(i < NUM_SYMBOLS)␊ |
| ␉␉␉␉{␊ |
| ␉␉␉␉␉if(strcmp(symbolString, kernelSymbols[i]) == 0)␊ |
| ␉␉␉␉␉{␊ |
| ␉␉␉␉␉␉symbolIndexes[i] = symbolIndex;␊ |
| ␉␉␉␉␉␉numSymbolsFound++;␉␉␉␉␊ |
| ␉␉␉␉␉} ␊ |
| ␉␉␉␉␉␊ |
| ␉␉␉␉}␊ |
| ␉␉␉␉symbolString += strlen(symbolString) + 1;␊ |
| ␉␉␉␉symbolIndex++;␊ |
| ␉␉␉}␊ |
| ␉␉␉␊ |
| ␉␉␉// loop again␊ |
| ␉␉␉symbolIndex = 0;␊ |
| ␉␉␉numSymbolsFound = 0;␊ |
| ␉␉␉while(symbolIndex < symtableData->nsyms && numSymbolsFound < NUM_SYMBOLS)␉// TODO: for loop␊ |
| ␉␉␉{␊ |
| ␉␉␉␉␊ |
| ␉␉␉␉symbolEntry = kernelData + symtableData->symoff + (symbolIndex * sizeof(struct nlist));␊ |
| ␉␉␉␉␊ |
| ␉␉␉␉int i = 0;␊ |
| ␉␉␉␉while(i < NUM_SYMBOLS)␊ |
| ␉␉␉␉{␊ |
| ␉␉␉␉␉if(symbolIndex == (symbolIndexes[i] - 4))␊ |
| ␉␉␉␉␉{␊ |
| ␉␉␉␉␉␉kernelSymbolAddresses[i] = (UInt32)symbolEntry->n_value;␊ |
| ␉␉␉␉␉␉numSymbolsFound++;␉␉␉␉␊ |
| ␉␉␉␉␉} ␊ |
| ␉␉␉␉␉␊ |
| ␉␉␉␉}␊ |
| ␉␉␉␉␊ |
| ␉␉␉␉symbolIndex ++;␊ |
| ␉␉␉}␉␉␉␊ |
| ␉␉// Load commands should be anded with 0x7FFFFFFF to ignore the␉LC_REQ_DYLD flag␊ |
| ␉␉} else if((loadCommand->cmd & 0x7FFFFFFF) == LC_SEGMENT)␉␉// We only care about the __TEXT segment, any other load command can be ignored␊ |
| ␉␉{␊ |
| ␉␉␉␊ |
| ␉␉␉struct segment_command *segCommand;␊ |
| ␉␉␉␊ |
| ␉␉␉segCommand = kernelData + kernelIndex;␊ |
| ␉␉␉␊ |
| ␉␉␉//printf("Segment name is %s\n", segCommand->segname);␊ |
| ␉␉␉␊ |
| ␉␉␉if(strcmp("__TEXT", segCommand->segname) == 0)␊ |
| ␉␉␉{␊ |
| ␉␉␉␉UInt32 sectionIndex;␊ |
| ␉␉␉␉␊ |
| ␉␉␉␉sectionIndex = sizeof(struct segment_command);␊ |
| ␉␉␉␉␊ |
| ␉␉␉␉struct section *sect;␊ |
| ␉␉␉␉␊ |
| ␉␉␉␉while(sectionIndex < segCommand->cmdsize)␊ |
| ␉␉␉␉{␊ |
| ␉␉␉␉␉sect = kernelData + kernelIndex + sectionIndex;␊ |
| ␉␉␉␉␉␊ |
| ␉␉␉␉␉sectionIndex += sizeof(struct section);␊ |
| ␉␉␉␉␉␊ |
| ␉␉␉␉␉␊ |
| ␉␉␉␉␉if(strcmp("__text", sect->sectname) == 0)␊ |
| ␉␉␉␉␉{␊ |
| ␉␉␉␉␉␉// __TEXT,__text found, save the offset and address for when looking for the panic call.␊ |
| ␉␉␉␉␉␉textSection = sect->offset;␊ |
| ␉␉␉␉␉␉textAddress = sect->addr;␊ |
| ␉␉␉␉␉␉break;␊ |
| ␉␉␉␉␉}␉␉␉␉␉␊ |
| ␉␉␉␉}␊ |
| ␉␉␉}␊ |
| ␉␉␉␊ |
| ␉␉␉␊ |
| ␉␉␉kernelIndex += cmdSize;␊ |
| ␉␉} else {␊ |
| ␉␉␉kernelIndex += cmdSize;␊ |
| ␉␉}␊ |
| ␉}␊ |
| ␉␊ |
| ␉return KERNEL_32;␊ |
| }␊ |
| ␊ |
| /**␊ |
| ** Locate the fisrt instance of _panic inside of _cpuid_set_info, and remove it␊ |
| **/␊ |
| void patch_cpuid_set_info(void* kernelData)␊ |
| {␊ |
| ␉UInt8* bytes = (void*)kernelData;␊ |
| ␉UInt32 patchLocation = (kernelSymbolAddresses[SYMBOL_CPUID_SET_INFO] - textAddress + textSection);␊ |
| ␉UInt32 panidAddr = kernelSymbolAddresses[SYMBOL_PANIC] - textAddress;␊ |
| ␉␊ |
| ␉␊ |
| ␉//TODO: don't assume it'll always work (Look for *next* function address in symtab and fail once it's been reached)␊ |
| ␉while( ␊ |
| ␉␉ (bytes[patchLocation -1] != 0xE8) ||␊ |
| ␉␉ ( ( (UInt32)(panidAddr - patchLocation - 4) + textSection ) != (UInt32)((bytes[patchLocation] | ␊ |
| ␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉bytes[patchLocation + 1] << 8 | ␊ |
| ␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉bytes[patchLocation + 2] << 16 |␊ |
| ␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉bytes[patchLocation + 3] << 24))) //&&␊ |
| ␉␉ ␊ |
| ␉␉ // (patchLocation < maxLocation)␉// max location is not known... assuming there is a panic call somewhere after cpuid_set_info␊ |
| ␉␉ )␊ |
| ␉{␊ |
| ␉␉patchLocation++;␊ |
| ␉}␊ |
| ␉␊ |
| ␉// repace with nops␊ |
| ␉bytes[patchLocation - 1] = 0x90;␊ |
| ␉bytes[patchLocation ] = 0x90;␊ |
| ␉bytes[patchLocation + 1] = 0x90;␊ |
| ␉bytes[patchLocation + 2] = 0x90;␊ |
| ␉bytes[patchLocation + 3] = 0x90;␊ |
| ␉␊ |
| ␉// Patching finished␊ |
| }␊ |
| ␊ |
| /**␊ |
| ** SleepEnabler.kext replacement (for those that need it)␊ |
| ** Located the KERN_INVALID_ARGUMENT return and replace it with KERN_SUCCESS␊ |
| **/␊ |
| void patch_pmCPUExitHaltToOff(void* kernelData)␊ |
| {␊ |
| ␉UInt8* bytes = (void*)kernelData;␊ |
| ␉UInt32 patchLocation = (kernelSymbolAddresses[SYMBOL_PMCPUEXITHALTTOOFF] - textAddress + textSection);␊ |
| ␊ |
| ␉while(bytes[patchLocation - 1]␉!= 0xB8 ||␊ |
| ␉␉ bytes[patchLocation]␉␉!= 0x04 ||␉// KERN_INVALID_ARGUMENT (0x00000004)␊ |
| ␉␉ bytes[patchLocation + 1]␉!= 0x00 ||␉// KERN_INVALID_ARGUMENT␊ |
| ␉␉ bytes[patchLocation + 2]␉!= 0x00 ||␉// KERN_INVALID_ARGUMENT␊ |
| ␉␉ bytes[patchLocation + 3]␉!= 0x00)␉// KERN_INVALID_ARGUMENT␊ |
| ␊ |
| ␉{␊ |
| ␉␉patchLocation++;␊ |
| ␉}␊ |
| ␉bytes[patchLocation] = 0x00;␉// KERN_SUCCESS;␊ |
| ␊ |
| }␊ |
