forked from mirrors/gecko-dev
4e9cf83ee8
MozReview-Commit-ID: Kdz2xtTF9EG --HG-- extra : rebase_source : 7235b3802f25bab29a8c6ba40a181a722f3df0ce
789 lines
25 KiB
C
789 lines
25 KiB
C
// Copied from upstream at revision 195c13743fe0ebc658714e2a9567d86529f20443.
|
|
// mach_override.c semver:1.2.0
|
|
// Copyright (c) 2003-2012 Jonathan 'Wolf' Rentzsch: http://rentzsch.com
|
|
// Some rights reserved: http://opensource.org/licenses/mit
|
|
// https://github.com/rentzsch/mach_override
|
|
|
|
#include "mach_override.h"
|
|
|
|
#include <mach-o/dyld.h>
|
|
#include <mach/mach_host.h>
|
|
#include <mach/mach_init.h>
|
|
#include <mach/vm_map.h>
|
|
#include <sys/mman.h>
|
|
|
|
#include <CoreServices/CoreServices.h>
|
|
|
|
/**************************
|
|
*
|
|
* Constants
|
|
*
|
|
**************************/
|
|
#pragma mark -
|
|
#pragma mark (Constants)
|
|
|
|
#define kPageSize 4096
|
|
#if defined(__ppc__) || defined(__POWERPC__)
|
|
|
|
long kIslandTemplate[] = {
|
|
0x9001FFFC, // stw r0,-4(SP)
|
|
0x3C00DEAD, // lis r0,0xDEAD
|
|
0x6000BEEF, // ori r0,r0,0xBEEF
|
|
0x7C0903A6, // mtctr r0
|
|
0x8001FFFC, // lwz r0,-4(SP)
|
|
0x60000000, // nop ; optionally replaced
|
|
0x4E800420 // bctr
|
|
};
|
|
|
|
#define kAddressHi 3
|
|
#define kAddressLo 5
|
|
#define kInstructionHi 10
|
|
#define kInstructionLo 11
|
|
|
|
#elif defined(__i386__)
|
|
|
|
#define kOriginalInstructionsSize 16
|
|
// On X86 we migh need to instert an add with a 32 bit immediate after the
|
|
// original instructions.
|
|
#define kMaxFixupSizeIncrease 5
|
|
|
|
unsigned char kIslandTemplate[] = {
|
|
// kOriginalInstructionsSize nop instructions so that we
|
|
// should have enough space to host original instructions
|
|
0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
|
|
0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
|
|
// Now the real jump instruction
|
|
0xE9, 0xEF, 0xBE, 0xAD, 0xDE
|
|
};
|
|
|
|
#define kInstructions 0
|
|
#define kJumpAddress kInstructions + kOriginalInstructionsSize + 1
|
|
#elif defined(__x86_64__)
|
|
|
|
#define kOriginalInstructionsSize 32
|
|
// On X86-64 we never need to instert a new instruction.
|
|
#define kMaxFixupSizeIncrease 0
|
|
|
|
#define kJumpAddress kOriginalInstructionsSize + 6
|
|
|
|
unsigned char kIslandTemplate[] = {
|
|
// kOriginalInstructionsSize nop instructions so that we
|
|
// should have enough space to host original instructions
|
|
0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
|
|
0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
|
|
0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
|
|
0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
|
|
// Now the real jump instruction
|
|
0xFF, 0x25, 0x00, 0x00, 0x00, 0x00,
|
|
0x00, 0x00, 0x00, 0x00,
|
|
0x00, 0x00, 0x00, 0x00
|
|
};
|
|
|
|
#endif
|
|
|
|
/**************************
|
|
*
|
|
* Data Types
|
|
*
|
|
**************************/
|
|
#pragma mark -
|
|
#pragma mark (Data Types)
|
|
|
|
typedef struct {
|
|
char instructions[sizeof(kIslandTemplate)];
|
|
} BranchIsland;
|
|
|
|
/**************************
|
|
*
|
|
* Funky Protos
|
|
*
|
|
**************************/
|
|
#pragma mark -
|
|
#pragma mark (Funky Protos)
|
|
|
|
static mach_error_t
|
|
allocateBranchIsland(
|
|
BranchIsland **island,
|
|
void *originalFunctionAddress);
|
|
|
|
mach_error_t
|
|
freeBranchIsland(
|
|
BranchIsland *island );
|
|
|
|
#if defined(__ppc__) || defined(__POWERPC__)
|
|
mach_error_t
|
|
setBranchIslandTarget(
|
|
BranchIsland *island,
|
|
const void *branchTo,
|
|
long instruction );
|
|
#endif
|
|
|
|
#if defined(__i386__) || defined(__x86_64__)
|
|
mach_error_t
|
|
setBranchIslandTarget_i386(
|
|
BranchIsland *island,
|
|
const void *branchTo,
|
|
char* instructions );
|
|
void
|
|
atomic_mov64(
|
|
uint64_t *targetAddress,
|
|
uint64_t value );
|
|
|
|
static Boolean
|
|
eatKnownInstructions(
|
|
unsigned char *code,
|
|
uint64_t *newInstruction,
|
|
int *howManyEaten,
|
|
char *originalInstructions,
|
|
int *originalInstructionCount,
|
|
uint8_t *originalInstructionSizes );
|
|
|
|
static void
|
|
fixupInstructions(
|
|
uint32_t offset,
|
|
void *instructionsToFix,
|
|
int instructionCount,
|
|
uint8_t *instructionSizes );
|
|
#endif
|
|
|
|
/*******************************************************************************
|
|
*
|
|
* Interface
|
|
*
|
|
*******************************************************************************/
|
|
#pragma mark -
|
|
#pragma mark (Interface)
|
|
|
|
#if defined(__i386__) || defined(__x86_64__)
|
|
mach_error_t makeIslandExecutable(void *address) {
|
|
mach_error_t err = err_none;
|
|
uintptr_t page = (uintptr_t)address & ~(uintptr_t)(kPageSize-1);
|
|
int e = err_none;
|
|
e |= mprotect((void *)page, kPageSize, PROT_EXEC | PROT_READ | PROT_WRITE);
|
|
e |= msync((void *)page, kPageSize, MS_INVALIDATE );
|
|
if (e) {
|
|
err = err_cannot_override;
|
|
}
|
|
return err;
|
|
}
|
|
#endif
|
|
|
|
mach_error_t
|
|
mach_override_ptr(
|
|
void *originalFunctionAddress,
|
|
const void *overrideFunctionAddress,
|
|
void **originalFunctionReentryIsland )
|
|
{
|
|
assert( originalFunctionAddress );
|
|
assert( overrideFunctionAddress );
|
|
|
|
// this addresses overriding such functions as AudioOutputUnitStart()
|
|
// test with modified DefaultOutputUnit project
|
|
#if defined(__x86_64__)
|
|
for(;;){
|
|
if(*(uint16_t*)originalFunctionAddress==0x25FF) // jmp qword near [rip+0x????????]
|
|
originalFunctionAddress=*(void**)((char*)originalFunctionAddress+6+*(int32_t *)((uint16_t*)originalFunctionAddress+1));
|
|
else break;
|
|
}
|
|
#elif defined(__i386__)
|
|
for(;;){
|
|
if(*(uint16_t*)originalFunctionAddress==0x25FF) // jmp *0x????????
|
|
originalFunctionAddress=**(void***)((uint16_t*)originalFunctionAddress+1);
|
|
else break;
|
|
}
|
|
#endif
|
|
|
|
long *originalFunctionPtr = (long*) originalFunctionAddress;
|
|
mach_error_t err = err_none;
|
|
|
|
#if defined(__ppc__) || defined(__POWERPC__)
|
|
// Ensure first instruction isn't 'mfctr'.
|
|
#define kMFCTRMask 0xfc1fffff
|
|
#define kMFCTRInstruction 0x7c0903a6
|
|
|
|
long originalInstruction = *originalFunctionPtr;
|
|
if( !err && ((originalInstruction & kMFCTRMask) == kMFCTRInstruction) )
|
|
err = err_cannot_override;
|
|
#elif defined(__i386__) || defined(__x86_64__)
|
|
int eatenCount = 0;
|
|
int originalInstructionCount = 0;
|
|
char originalInstructions[kOriginalInstructionsSize];
|
|
uint8_t originalInstructionSizes[kOriginalInstructionsSize];
|
|
uint64_t jumpRelativeInstruction = 0; // JMP
|
|
|
|
Boolean overridePossible = eatKnownInstructions ((unsigned char *)originalFunctionPtr,
|
|
&jumpRelativeInstruction, &eatenCount,
|
|
originalInstructions, &originalInstructionCount,
|
|
originalInstructionSizes );
|
|
if (eatenCount + kMaxFixupSizeIncrease > kOriginalInstructionsSize) {
|
|
//printf ("Too many instructions eaten\n");
|
|
overridePossible = false;
|
|
}
|
|
if (!overridePossible) err = err_cannot_override;
|
|
if (err) fprintf(stderr, "err = %x %s:%d\n", err, __FILE__, __LINE__);
|
|
#endif
|
|
|
|
// Make the original function implementation writable.
|
|
if( !err ) {
|
|
err = vm_protect( mach_task_self(),
|
|
(vm_address_t) originalFunctionPtr, 8, false,
|
|
(VM_PROT_ALL | VM_PROT_COPY) );
|
|
if( err )
|
|
err = vm_protect( mach_task_self(),
|
|
(vm_address_t) originalFunctionPtr, 8, false,
|
|
(VM_PROT_DEFAULT | VM_PROT_COPY) );
|
|
}
|
|
if (err) fprintf(stderr, "err = %x %s:%d\n", err, __FILE__, __LINE__);
|
|
|
|
// Allocate and target the escape island to the overriding function.
|
|
BranchIsland *escapeIsland = NULL;
|
|
if( !err )
|
|
err = allocateBranchIsland( &escapeIsland, originalFunctionAddress );
|
|
if (err) fprintf(stderr, "err = %x %s:%d\n", err, __FILE__, __LINE__);
|
|
|
|
|
|
#if defined(__ppc__) || defined(__POWERPC__)
|
|
if( !err )
|
|
err = setBranchIslandTarget( escapeIsland, overrideFunctionAddress, 0 );
|
|
|
|
// Build the branch absolute instruction to the escape island.
|
|
long branchAbsoluteInstruction = 0; // Set to 0 just to silence warning.
|
|
if( !err ) {
|
|
long escapeIslandAddress = ((long) escapeIsland) & 0x3FFFFFF;
|
|
branchAbsoluteInstruction = 0x48000002 | escapeIslandAddress;
|
|
}
|
|
#elif defined(__i386__) || defined(__x86_64__)
|
|
if (err) fprintf(stderr, "err = %x %s:%d\n", err, __FILE__, __LINE__);
|
|
|
|
if( !err )
|
|
err = setBranchIslandTarget_i386( escapeIsland, overrideFunctionAddress, 0 );
|
|
|
|
if (err) fprintf(stderr, "err = %x %s:%d\n", err, __FILE__, __LINE__);
|
|
// Build the jump relative instruction to the escape island
|
|
#endif
|
|
|
|
|
|
#if defined(__i386__) || defined(__x86_64__)
|
|
if (!err) {
|
|
uint32_t addressOffset = ((char*)escapeIsland - (char*)originalFunctionPtr - 5);
|
|
addressOffset = OSSwapInt32(addressOffset);
|
|
|
|
jumpRelativeInstruction |= 0xE900000000000000LL;
|
|
jumpRelativeInstruction |= ((uint64_t)addressOffset & 0xffffffff) << 24;
|
|
jumpRelativeInstruction = OSSwapInt64(jumpRelativeInstruction);
|
|
}
|
|
#endif
|
|
|
|
// Optionally allocate & return the reentry island. This may contain relocated
|
|
// jmp instructions and so has all the same addressing reachability requirements
|
|
// the escape island has to the original function, except the escape island is
|
|
// technically our original function.
|
|
BranchIsland *reentryIsland = NULL;
|
|
if( !err && originalFunctionReentryIsland ) {
|
|
err = allocateBranchIsland( &reentryIsland, escapeIsland);
|
|
if( !err )
|
|
*originalFunctionReentryIsland = reentryIsland;
|
|
}
|
|
|
|
#if defined(__ppc__) || defined(__POWERPC__)
|
|
// Atomically:
|
|
// o If the reentry island was allocated:
|
|
// o Insert the original instruction into the reentry island.
|
|
// o Target the reentry island at the 2nd instruction of the
|
|
// original function.
|
|
// o Replace the original instruction with the branch absolute.
|
|
if( !err ) {
|
|
int escapeIslandEngaged = false;
|
|
do {
|
|
if( reentryIsland )
|
|
err = setBranchIslandTarget( reentryIsland,
|
|
(void*) (originalFunctionPtr+1), originalInstruction );
|
|
if( !err ) {
|
|
escapeIslandEngaged = CompareAndSwap( originalInstruction,
|
|
branchAbsoluteInstruction,
|
|
(UInt32*)originalFunctionPtr );
|
|
if( !escapeIslandEngaged ) {
|
|
// Someone replaced the instruction out from under us,
|
|
// re-read the instruction, make sure it's still not
|
|
// 'mfctr' and try again.
|
|
originalInstruction = *originalFunctionPtr;
|
|
if( (originalInstruction & kMFCTRMask) == kMFCTRInstruction)
|
|
err = err_cannot_override;
|
|
}
|
|
}
|
|
} while( !err && !escapeIslandEngaged );
|
|
}
|
|
#elif defined(__i386__) || defined(__x86_64__)
|
|
// Atomically:
|
|
// o If the reentry island was allocated:
|
|
// o Insert the original instructions into the reentry island.
|
|
// o Target the reentry island at the first non-replaced
|
|
// instruction of the original function.
|
|
// o Replace the original first instructions with the jump relative.
|
|
//
|
|
// Note that on i386, we do not support someone else changing the code under our feet
|
|
if ( !err ) {
|
|
uint32_t offset = (uintptr_t)originalFunctionPtr - (uintptr_t)reentryIsland;
|
|
fixupInstructions(offset, originalInstructions,
|
|
originalInstructionCount, originalInstructionSizes );
|
|
|
|
if( reentryIsland )
|
|
err = setBranchIslandTarget_i386( reentryIsland,
|
|
(void*) ((char *)originalFunctionPtr+eatenCount), originalInstructions );
|
|
// try making islands executable before planting the jmp
|
|
#if defined(__x86_64__) || defined(__i386__)
|
|
if( !err )
|
|
err = makeIslandExecutable(escapeIsland);
|
|
if( !err && reentryIsland )
|
|
err = makeIslandExecutable(reentryIsland);
|
|
#endif
|
|
if ( !err )
|
|
atomic_mov64((uint64_t *)originalFunctionPtr, jumpRelativeInstruction);
|
|
}
|
|
#endif
|
|
|
|
// Clean up on error.
|
|
if( err ) {
|
|
if( reentryIsland )
|
|
freeBranchIsland( reentryIsland );
|
|
if( escapeIsland )
|
|
freeBranchIsland( escapeIsland );
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
/*******************************************************************************
|
|
*
|
|
* Implementation
|
|
*
|
|
*******************************************************************************/
|
|
#pragma mark -
|
|
#pragma mark (Implementation)
|
|
|
|
static bool jump_in_range(intptr_t from, intptr_t to) {
|
|
intptr_t field_value = to - from - 5;
|
|
int32_t field_value_32 = field_value;
|
|
return field_value == field_value_32;
|
|
}
|
|
|
|
/*******************************************************************************
|
|
Implementation: Allocates memory for a branch island.
|
|
|
|
@param island <- The allocated island.
|
|
@result <- mach_error_t
|
|
|
|
***************************************************************************/
|
|
|
|
static mach_error_t
|
|
allocateBranchIslandAux(
|
|
BranchIsland **island,
|
|
void *originalFunctionAddress,
|
|
bool forward)
|
|
{
|
|
assert( island );
|
|
assert( sizeof( BranchIsland ) <= kPageSize );
|
|
|
|
vm_map_t task_self = mach_task_self();
|
|
vm_address_t original_address = (vm_address_t) originalFunctionAddress;
|
|
vm_address_t address = original_address;
|
|
|
|
for (;;) {
|
|
vm_size_t vmsize = 0;
|
|
memory_object_name_t object = 0;
|
|
kern_return_t kr = 0;
|
|
vm_region_flavor_t flavor = VM_REGION_BASIC_INFO;
|
|
// Find the region the address is in.
|
|
#if __WORDSIZE == 32
|
|
vm_region_basic_info_data_t info;
|
|
mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT;
|
|
kr = vm_region(task_self, &address, &vmsize, flavor,
|
|
(vm_region_info_t)&info, &info_count, &object);
|
|
#else
|
|
vm_region_basic_info_data_64_t info;
|
|
mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT_64;
|
|
kr = vm_region_64(task_self, &address, &vmsize, flavor,
|
|
(vm_region_info_t)&info, &info_count, &object);
|
|
#endif
|
|
if (kr != KERN_SUCCESS)
|
|
return kr;
|
|
assert((address & (kPageSize - 1)) == 0);
|
|
|
|
// Go to the first page before or after this region
|
|
vm_address_t new_address = forward ? address + vmsize : address - kPageSize;
|
|
#if __WORDSIZE == 64
|
|
if(!jump_in_range(original_address, new_address))
|
|
break;
|
|
#endif
|
|
address = new_address;
|
|
|
|
// Try to allocate this page.
|
|
kr = vm_allocate(task_self, &address, kPageSize, 0);
|
|
if (kr == KERN_SUCCESS) {
|
|
*island = (BranchIsland*) address;
|
|
return err_none;
|
|
}
|
|
if (kr != KERN_NO_SPACE)
|
|
return kr;
|
|
}
|
|
|
|
return KERN_NO_SPACE;
|
|
}
|
|
|
|
static mach_error_t
|
|
allocateBranchIsland(
|
|
BranchIsland **island,
|
|
void *originalFunctionAddress)
|
|
{
|
|
mach_error_t err =
|
|
allocateBranchIslandAux(island, originalFunctionAddress, true);
|
|
if (!err)
|
|
return err;
|
|
return allocateBranchIslandAux(island, originalFunctionAddress, false);
|
|
}
|
|
|
|
|
|
/*******************************************************************************
|
|
Implementation: Deallocates memory for a branch island.
|
|
|
|
@param island -> The island to deallocate.
|
|
@result <- mach_error_t
|
|
|
|
***************************************************************************/
|
|
|
|
mach_error_t
|
|
freeBranchIsland(
|
|
BranchIsland *island )
|
|
{
|
|
assert( island );
|
|
assert( (*(long*)&island->instructions[0]) == kIslandTemplate[0] );
|
|
assert( sizeof( BranchIsland ) <= kPageSize );
|
|
return vm_deallocate( mach_task_self(), (vm_address_t) island,
|
|
kPageSize );
|
|
}
|
|
|
|
/*******************************************************************************
|
|
Implementation: Sets the branch island's target, with an optional
|
|
instruction.
|
|
|
|
@param island -> The branch island to insert target into.
|
|
@param branchTo -> The address of the target.
|
|
@param instruction -> Optional instruction to execute prior to branch. Set
|
|
to zero for nop.
|
|
@result <- mach_error_t
|
|
|
|
***************************************************************************/
|
|
#if defined(__ppc__) || defined(__POWERPC__)
|
|
mach_error_t
|
|
setBranchIslandTarget(
|
|
BranchIsland *island,
|
|
const void *branchTo,
|
|
long instruction )
|
|
{
|
|
// Copy over the template code.
|
|
bcopy( kIslandTemplate, island->instructions, sizeof( kIslandTemplate ) );
|
|
|
|
// Fill in the address.
|
|
((short*)island->instructions)[kAddressLo] = ((long) branchTo) & 0x0000FFFF;
|
|
((short*)island->instructions)[kAddressHi]
|
|
= (((long) branchTo) >> 16) & 0x0000FFFF;
|
|
|
|
// Fill in the (optional) instuction.
|
|
if( instruction != 0 ) {
|
|
((short*)island->instructions)[kInstructionLo]
|
|
= instruction & 0x0000FFFF;
|
|
((short*)island->instructions)[kInstructionHi]
|
|
= (instruction >> 16) & 0x0000FFFF;
|
|
}
|
|
|
|
//MakeDataExecutable( island->instructions, sizeof( kIslandTemplate ) );
|
|
msync( island->instructions, sizeof( kIslandTemplate ), MS_INVALIDATE );
|
|
|
|
return err_none;
|
|
}
|
|
#endif
|
|
|
|
#if defined(__i386__)
|
|
mach_error_t
|
|
setBranchIslandTarget_i386(
|
|
BranchIsland *island,
|
|
const void *branchTo,
|
|
char* instructions )
|
|
{
|
|
|
|
// Copy over the template code.
|
|
bcopy( kIslandTemplate, island->instructions, sizeof( kIslandTemplate ) );
|
|
|
|
// copy original instructions
|
|
if (instructions) {
|
|
bcopy (instructions, island->instructions + kInstructions, kOriginalInstructionsSize);
|
|
}
|
|
|
|
// Fill in the address.
|
|
int32_t addressOffset = (char *)branchTo - (island->instructions + kJumpAddress + 4);
|
|
*((int32_t *)(island->instructions + kJumpAddress)) = addressOffset;
|
|
|
|
msync( island->instructions, sizeof( kIslandTemplate ), MS_INVALIDATE );
|
|
return err_none;
|
|
}
|
|
|
|
#elif defined(__x86_64__)
|
|
mach_error_t
|
|
setBranchIslandTarget_i386(
|
|
BranchIsland *island,
|
|
const void *branchTo,
|
|
char* instructions )
|
|
{
|
|
// Copy over the template code.
|
|
bcopy( kIslandTemplate, island->instructions, sizeof( kIslandTemplate ) );
|
|
|
|
// Copy original instructions.
|
|
if (instructions) {
|
|
bcopy (instructions, island->instructions, kOriginalInstructionsSize);
|
|
}
|
|
|
|
// Fill in the address.
|
|
*((uint64_t *)(island->instructions + kJumpAddress)) = (uint64_t)branchTo;
|
|
msync( island->instructions, sizeof( kIslandTemplate ), MS_INVALIDATE );
|
|
|
|
return err_none;
|
|
}
|
|
#endif
|
|
|
|
|
|
#if defined(__i386__) || defined(__x86_64__)
|
|
// simplistic instruction matching
|
|
typedef struct {
|
|
unsigned int length; // max 15
|
|
unsigned char mask[15]; // sequence of bytes in memory order
|
|
unsigned char constraint[15]; // sequence of bytes in memory order
|
|
} AsmInstructionMatch;
|
|
|
|
#if defined(__i386__)
|
|
static AsmInstructionMatch possibleInstructions[] = {
|
|
{ 0x5, {0xFF, 0x00, 0x00, 0x00, 0x00}, {0xE9, 0x00, 0x00, 0x00, 0x00} }, // jmp 0x????????
|
|
{ 0x5, {0xFF, 0xFF, 0xFF, 0xFF, 0xFF}, {0x55, 0x89, 0xe5, 0xc9, 0xc3} }, // push %ebp; mov %esp,%ebp; leave; ret
|
|
{ 0x1, {0xFF}, {0x90} }, // nop
|
|
{ 0x1, {0xFF}, {0x55} }, // push %esp
|
|
{ 0x2, {0xFF, 0xFF}, {0x89, 0xE5} }, // mov %esp,%ebp
|
|
{ 0x1, {0xFF}, {0x53} }, // push %ebx
|
|
{ 0x3, {0xFF, 0xFF, 0x00}, {0x83, 0xEC, 0x00} }, // sub 0x??, %esp
|
|
{ 0x6, {0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00}, {0x81, 0xEC, 0x00, 0x00, 0x00, 0x00} }, // sub 0x??, %esp with 32bit immediate
|
|
{ 0x1, {0xFF}, {0x57} }, // push %edi
|
|
{ 0x1, {0xFF}, {0x56} }, // push %esi
|
|
{ 0x2, {0xFF, 0xFF}, {0x31, 0xC0} }, // xor %eax, %eax
|
|
{ 0x3, {0xFF, 0x4F, 0x00}, {0x8B, 0x45, 0x00} }, // mov $imm(%ebp), %reg
|
|
{ 0x3, {0xFF, 0x4C, 0x00}, {0x8B, 0x40, 0x00} }, // mov $imm(%eax-%edx), %reg
|
|
{ 0x4, {0xFF, 0xFF, 0xFF, 0x00}, {0x8B, 0x4C, 0x24, 0x00} }, // mov $imm(%esp), %ecx
|
|
{ 0x5, {0xFF, 0x00, 0x00, 0x00, 0x00}, {0xB8, 0x00, 0x00, 0x00, 0x00} }, // mov $imm, %eax
|
|
{ 0x6, {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}, {0xE8, 0x00, 0x00, 0x00, 0x00, 0x58} }, // call $imm; pop %eax
|
|
{ 0x0 }
|
|
};
|
|
#elif defined(__x86_64__)
|
|
static AsmInstructionMatch possibleInstructions[] = {
|
|
{ 0x5, {0xFF, 0x00, 0x00, 0x00, 0x00}, {0xE9, 0x00, 0x00, 0x00, 0x00} }, // jmp 0x????????
|
|
{ 0x1, {0xFF}, {0x90} }, // nop
|
|
{ 0x1, {0xF8}, {0x50} }, // push %rX
|
|
{ 0x3, {0xFF, 0xFF, 0xFF}, {0x48, 0x89, 0xE5} }, // mov %rsp,%rbp
|
|
{ 0x4, {0xFF, 0xFF, 0xFF, 0x00}, {0x48, 0x83, 0xEC, 0x00} }, // sub 0x??, %rsp
|
|
{ 0x4, {0xFB, 0xFF, 0x00, 0x00}, {0x48, 0x89, 0x00, 0x00} }, // move onto rbp
|
|
{ 0x4, {0xFF, 0xFF, 0xFF, 0xFF}, {0x40, 0x0f, 0xbe, 0xce} }, // movsbl %sil, %ecx
|
|
{ 0x2, {0xFF, 0x00}, {0x41, 0x00} }, // push %rXX
|
|
{ 0x2, {0xFF, 0x00}, {0x85, 0x00} }, // test %rX,%rX
|
|
{ 0x5, {0xF8, 0x00, 0x00, 0x00, 0x00}, {0xB8, 0x00, 0x00, 0x00, 0x00} }, // mov $imm, %reg
|
|
{ 0x3, {0xFF, 0xFF, 0x00}, {0xFF, 0x77, 0x00} }, // pushq $imm(%rdi)
|
|
{ 0x2, {0xFF, 0xFF}, {0x31, 0xC0} }, // xor %eax, %eax
|
|
{ 0x2, {0xFF, 0xFF}, {0x89, 0xF8} }, // mov %edi, %eax
|
|
|
|
//leaq offset(%rip),%rax
|
|
{ 0x7, {0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00}, {0x48, 0x8d, 0x05, 0x00, 0x00, 0x00, 0x00} },
|
|
|
|
{ 0x0 }
|
|
};
|
|
#endif
|
|
|
|
static Boolean codeMatchesInstruction(unsigned char *code, AsmInstructionMatch* instruction)
|
|
{
|
|
Boolean match = true;
|
|
|
|
size_t i;
|
|
for (i=0; i<instruction->length; i++) {
|
|
unsigned char mask = instruction->mask[i];
|
|
unsigned char constraint = instruction->constraint[i];
|
|
unsigned char codeValue = code[i];
|
|
|
|
match = ((codeValue & mask) == constraint);
|
|
if (!match) break;
|
|
}
|
|
|
|
return match;
|
|
}
|
|
|
|
#if defined(__i386__) || defined(__x86_64__)
|
|
static Boolean
|
|
eatKnownInstructions(
|
|
unsigned char *code,
|
|
uint64_t *newInstruction,
|
|
int *howManyEaten,
|
|
char *originalInstructions,
|
|
int *originalInstructionCount,
|
|
uint8_t *originalInstructionSizes )
|
|
{
|
|
Boolean allInstructionsKnown = true;
|
|
int totalEaten = 0;
|
|
unsigned char* ptr = code;
|
|
int remainsToEat = 5; // a JMP instruction takes 5 bytes
|
|
int instructionIndex = 0;
|
|
|
|
if (howManyEaten) *howManyEaten = 0;
|
|
if (originalInstructionCount) *originalInstructionCount = 0;
|
|
while (remainsToEat > 0) {
|
|
Boolean curInstructionKnown = false;
|
|
|
|
// See if instruction matches one we know
|
|
AsmInstructionMatch* curInstr = possibleInstructions;
|
|
do {
|
|
if ((curInstructionKnown = codeMatchesInstruction(ptr, curInstr))) break;
|
|
curInstr++;
|
|
} while (curInstr->length > 0);
|
|
|
|
// if all instruction matches failed, we don't know current instruction then, stop here
|
|
if (!curInstructionKnown) {
|
|
allInstructionsKnown = false;
|
|
fprintf(stderr, "mach_override: some instructions unknown! Need to update mach_override.c\n");
|
|
break;
|
|
}
|
|
|
|
// At this point, we've matched curInstr
|
|
int eaten = curInstr->length;
|
|
ptr += eaten;
|
|
remainsToEat -= eaten;
|
|
totalEaten += eaten;
|
|
|
|
if (originalInstructionSizes) originalInstructionSizes[instructionIndex] = eaten;
|
|
instructionIndex += 1;
|
|
if (originalInstructionCount) *originalInstructionCount = instructionIndex;
|
|
}
|
|
|
|
|
|
if (howManyEaten) *howManyEaten = totalEaten;
|
|
|
|
if (originalInstructions) {
|
|
Boolean enoughSpaceForOriginalInstructions = (totalEaten < kOriginalInstructionsSize);
|
|
|
|
if (enoughSpaceForOriginalInstructions) {
|
|
memset(originalInstructions, 0x90 /* NOP */, kOriginalInstructionsSize); // fill instructions with NOP
|
|
bcopy(code, originalInstructions, totalEaten);
|
|
} else {
|
|
// printf ("Not enough space in island to store original instructions. Adapt the island definition and kOriginalInstructionsSize\n");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
if (allInstructionsKnown) {
|
|
// save last 3 bytes of first 64bits of codre we'll replace
|
|
uint64_t currentFirst64BitsOfCode = *((uint64_t *)code);
|
|
currentFirst64BitsOfCode = OSSwapInt64(currentFirst64BitsOfCode); // back to memory representation
|
|
currentFirst64BitsOfCode &= 0x0000000000FFFFFFLL;
|
|
|
|
// keep only last 3 instructions bytes, first 5 will be replaced by JMP instr
|
|
*newInstruction &= 0xFFFFFFFFFF000000LL; // clear last 3 bytes
|
|
*newInstruction |= (currentFirst64BitsOfCode & 0x0000000000FFFFFFLL); // set last 3 bytes
|
|
}
|
|
|
|
return allInstructionsKnown;
|
|
}
|
|
|
|
static void
|
|
fixupInstructions(
|
|
uint32_t offset,
|
|
void *instructionsToFix,
|
|
int instructionCount,
|
|
uint8_t *instructionSizes )
|
|
{
|
|
// The start of "leaq offset(%rip),%rax"
|
|
static const uint8_t LeaqHeader[] = {0x48, 0x8d, 0x05};
|
|
|
|
int index;
|
|
for (index = 0;index < instructionCount;index += 1)
|
|
{
|
|
if (*(uint8_t*)instructionsToFix == 0xE9) // 32-bit jump relative
|
|
{
|
|
uint32_t *jumpOffsetPtr = (uint32_t*)((uintptr_t)instructionsToFix + 1);
|
|
*jumpOffsetPtr += offset;
|
|
}
|
|
|
|
// leaq offset(%rip),%rax
|
|
if (memcmp(instructionsToFix, LeaqHeader, 3) == 0) {
|
|
uint32_t *LeaqOffsetPtr = (uint32_t*)((uintptr_t)instructionsToFix + 3);
|
|
*LeaqOffsetPtr += offset;
|
|
}
|
|
|
|
// 32-bit call relative to the next addr; pop %eax
|
|
if (*(uint8_t*)instructionsToFix == 0xE8)
|
|
{
|
|
// Just this call is larger than the jump we use, so we
|
|
// know this is the last instruction.
|
|
assert(index == (instructionCount - 1));
|
|
assert(instructionSizes[index] == 6);
|
|
|
|
// Insert "addl $offset, %eax" in the end so that when
|
|
// we jump to the rest of the function %eax has the
|
|
// value it would have if eip had been pushed by the
|
|
// call in its original position.
|
|
uint8_t *op = instructionsToFix;
|
|
op += 6;
|
|
*op = 0x05; // addl
|
|
uint32_t *addImmPtr = (uint32_t*)(op + 1);
|
|
*addImmPtr = offset;
|
|
}
|
|
|
|
instructionsToFix = (void*)((uintptr_t)instructionsToFix + instructionSizes[index]);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#if defined(__i386__)
|
|
__asm(
|
|
".text;"
|
|
".align 2, 0x90;"
|
|
"_atomic_mov64:;"
|
|
" pushl %ebp;"
|
|
" movl %esp, %ebp;"
|
|
" pushl %esi;"
|
|
" pushl %ebx;"
|
|
" pushl %ecx;"
|
|
" pushl %eax;"
|
|
" pushl %edx;"
|
|
|
|
// atomic push of value to an address
|
|
// we use cmpxchg8b, which compares content of an address with
|
|
// edx:eax. If they are equal, it atomically puts 64bit value
|
|
// ecx:ebx in address.
|
|
// We thus put contents of address in edx:eax to force ecx:ebx
|
|
// in address
|
|
" mov 8(%ebp), %esi;" // esi contains target address
|
|
" mov 12(%ebp), %ebx;"
|
|
" mov 16(%ebp), %ecx;" // ecx:ebx now contains value to put in target address
|
|
" mov (%esi), %eax;"
|
|
" mov 4(%esi), %edx;" // edx:eax now contains value currently contained in target address
|
|
" lock; cmpxchg8b (%esi);" // atomic move.
|
|
|
|
// restore registers
|
|
" popl %edx;"
|
|
" popl %eax;"
|
|
" popl %ecx;"
|
|
" popl %ebx;"
|
|
" popl %esi;"
|
|
" popl %ebp;"
|
|
" ret"
|
|
);
|
|
#elif defined(__x86_64__)
|
|
void atomic_mov64(
|
|
uint64_t *targetAddress,
|
|
uint64_t value )
|
|
{
|
|
*targetAddress = value;
|
|
}
|
|
#endif
|
|
#endif
|