lysann/mach-detours
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity Actions

detour_transaction_commit

Browse source
This commit is contained in:
Lysann Tranvouez 2025-09-29 01:07:56 +02:00
parent b1eb0ad995
commit d8d3d85444
5 changed files with 351 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

1
.idea/codeStyles/Project.xml generated
View file

@ -13,6 +13,7 @@
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_ELSE_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_WHILE_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_CATCH_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_CASE_FROM_SWITCH/@EntryValue" value="true" type="bool" />
</RiderCodeStyleSettings>
</code_scheme>
</component>

1
.idea/editor.xml generated
View file

@ -249,6 +249,7 @@
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ANONYMOUS_METHOD_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/CASE_BLOCK_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/EMPTY_BLOCK_STYLE/@EntryValue" value="TOGETHER_SAME_LINE" type="string" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_CASE_FROM_SWITCH/@EntryValue" value="true" type="bool" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/OTHER_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_CATCH_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
<option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_ELSE_ON_NEW_LINE/@EntryValue" value="false" type="bool" />

93
src/arm64/detours_arm64.h
View file

@ -9,8 +9,8 @@
typedef struct detour_align
{
uint8_t obTarget;
uint8_t obTrampoline;
uint8_t offset_target;
uint8_t offset_trampoline;
} detour_align;
typedef struct detour_trampoline
@ -54,4 +54,93 @@ typedef struct detour_trampoline
static_assert(sizeof(detour_trampoline) == 192);
typedef uint32_t detours_arm64_opcode_t;
static inline detours_arm64_opcode_t fetch_opcode(uint8_t* code)
{
return *(detours_arm64_opcode_t*)code;
}
static inline void write_opcode(uint8_t** int_out_code, detours_arm64_opcode_t opcode)
{
uint8_t* code = *int_out_code;
*(detours_arm64_opcode_t*)code = opcode;
*int_out_code += sizeof(detours_arm64_opcode_t);
}
struct detours_arm64_indirect_jmp {
struct {
uint32_t Rd : 5;
uint32_t immhi : 19;
uint32_t iop : 5;
uint32_t immlo : 2;
uint32_t op : 1;
} ardp;
struct {
uint32_t Rt : 5;
uint32_t Rn : 5;
uint32_t imm : 12;
uint32_t opc : 2;
uint32_t iop1 : 2;
uint32_t V : 1;
uint32_t iop2 : 3;
uint32_t size : 2;
} ldr;
uint32_t br;
};
union detours_arm64_indirect_imm {
struct {
uint64_t pad : 12;
uint64_t adrp_immlo : 2;
uint64_t adrp_immhi : 19;
};
int64_t value;
};
static inline uint8_t* internal_detour_gen_jmp_indirect(uint8_t* code, uint64_t* jump_val)
{
// adrp x17, [jmpval]
// ldr x17, [x17, jmpval]
// br x17
union detours_arm64_indirect_imm jmp_ind_addr;
jmp_ind_addr.value = (((uint64_t)jump_val) & 0xFFFFFFFFFFFFF000) -
(((uint64_t)code) & 0xFFFFFFFFFFFFF000);
struct detours_arm64_indirect_jmp* ind_jmp = (struct detours_arm64_indirect_jmp*)code;
code = (uint8_t*)(ind_jmp + 1);
ind_jmp->ardp.Rd = 17;
ind_jmp->ardp.immhi = jmp_ind_addr.adrp_immhi;
ind_jmp->ardp.iop = 0x10;
ind_jmp->ardp.immlo = jmp_ind_addr.adrp_immlo;
ind_jmp->ardp.op = 1;
ind_jmp->ldr.Rt = 17;
ind_jmp->ldr.Rn = 17;
ind_jmp->ldr.imm = (((uint64_t)jump_val) & 0xFFF) / 8;
ind_jmp->ldr.opc = 1;
ind_jmp->ldr.iop1 = 1;
ind_jmp->ldr.V = 0;
ind_jmp->ldr.iop2 = 7;
ind_jmp->ldr.size = 3;
ind_jmp->br = 0xD61F0220;
return code;
}
static inline uint8_t* internal_detour_gen_brk(uint8_t* code, uint8_t* limit)
{
while (code < limit) {
write_opcode(&code, 0xd4100000 | (0xf000 << 5));
}
return code;
}
#endif //MACH_DETOURS_ARM64_H

4
src/detours_internal.h
View file

@ -25,4 +25,8 @@
#endif
#endif
#ifndef ARRAYSIZE
#define ARRAYSIZE(x) (sizeof(x)/sizeof(x[0]))
#endif
#endif //MACH_DETOURS_INTERNAL_H

260
src/mach_detours.c
View file

@ -6,6 +6,7 @@
#include "detours_internal.h"
#include "arm64/detours_arm64.h"
#include <inttypes.h>
#include <stdatomic.h>
#include <stdint.h>
#include <stdlib.h>
@ -13,14 +14,20 @@
#include <mach/mach.h>
#include <mach/mach_vm.h>
#ifdef __arm64__
#define DETOURS_ARM64
#else
#error Unsupported architecture (arm64)
#endif
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Trampoline Memory Management
typedef struct detour_region
{
uint32_t signature;
struct detour_region* next; // Next region in list of regions.
detour_trampoline* free_list_head; // List of free trampolines in this region.
struct detour_region* next; // Next region in list of regions.
detour_trampoline* free_list_head; // List of free trampolines in this region.
} detour_region;
static const uint32_t DETOUR_REGION_SIGNATURE = 'Rrtd';
@ -34,7 +41,8 @@ static mach_error_t internal_detour_writable_trampoline_regions()
// Mark all the regions as writable.
const mach_port_t port = mach_task_self();
for (detour_region* pRegion = s_regions_head; pRegion != NULL; pRegion = pRegion->next) {
const mach_error_t error = mach_vm_protect(port, (mach_vm_address_t)pRegion, DETOUR_REGION_SIZE, false, VM_PROT_READ | VM_PROT_WRITE);
const mach_error_t error = mach_vm_protect(port, (mach_vm_address_t)pRegion, DETOUR_REGION_SIZE, false,
VM_PROT_READ | VM_PROT_WRITE);
if (error != err_none) {
return error;
}
@ -47,7 +55,8 @@ static void internal_detour_runnable_trampoline_regions()
// Mark all the regions as executable.
const mach_port_t port = mach_task_self();
for (detour_region* pRegion = s_regions_head; pRegion != NULL; pRegion = pRegion->next) {
const mach_error_t error = mach_vm_protect(port, (mach_vm_address_t)pRegion, DETOUR_REGION_SIZE, false, VM_PROT_READ | VM_PROT_EXECUTE);
const mach_error_t error = mach_vm_protect(port, (mach_vm_address_t)pRegion, DETOUR_REGION_SIZE, false,
VM_PROT_READ | VM_PROT_EXECUTE);
if (error != err_none) {
DETOUR_BREAK();
}
@ -63,10 +72,78 @@ static void internal_detour_free_trampoline(detour_trampoline* trampoline)
region->free_list_head = trampoline;
}
static bool internal_detour_is_region_empty(detour_region* region)
{
// Stop if the region isn't a region (this would be bad).
if (region->signature != DETOUR_REGION_SIGNATURE) {
DETOUR_BREAK();
return false;
}
uint8_t* region_begin = (uint8_t*)region;
uint8_t* region_limit = region_begin + DETOUR_REGION_SIZE;
// Stop if any of the trampolines aren't free.
detour_trampoline* trampoline = ((detour_trampoline*)region) + 1;
for (int i = 0; i < DETOUR_TRAMPOLINES_PER_REGION; i++) {
if (trampoline[i].ptr_remain != NULL &&
(trampoline[i].ptr_remain < region_begin || trampoline[i].ptr_remain >= region_limit)) {
return false;
}
}
// OK, the region is empty.
return true;
}
static void internal_detour_free_unused_trampoline_regions()
{
detour_region** ptr_region_base = &s_regions_head;
detour_region* curr_region = s_regions_head;
const mach_port_t port = mach_task_self();
while (curr_region) {
if (internal_detour_is_region_empty(curr_region)) {
*ptr_region_base = curr_region->next;
vm_deallocate(port, (vm_address_t)curr_region, DETOUR_REGION_SIZE);
s_default_region = nullptr;
} else {
ptr_region_base = &curr_region->next;
}
curr_region = *ptr_region_base;
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Trampoline Helpers
static uint8_t internal_detour_align_from_trampoline(detour_trampoline* trampoline, uint8_t offset_trampoline)
{
for (int32_t n = 0; n < ARRAYSIZE(trampoline->align); n++) {
if (trampoline->align[n].offset_trampoline == offset_trampoline) {
return trampoline->align[n].offset_target;
}
}
return 0;
}
static uint8_t internal_detour_align_from_target(detour_trampoline* trampoline, uint8_t offset_target)
{
for (int32_t n = 0; n < ARRAYSIZE(trampoline->align); n++) {
if (trampoline->align[n].offset_target == offset_target) {
return trampoline->align[n].offset_trampoline;
}
}
return 0;
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Transactions
typedef enum detour_operation_kind {
typedef enum detour_operation_kind
{
detour_operation_kind_attach,
detour_operation_kind_detach,
} detour_operation_kind;
@ -87,6 +164,9 @@ typedef struct detour_pending_thread
thread_t thread;
} detour_pending_thread;
static bool s_ignore_too_small = false;
static bool s_retain_regions = false;
static _Atomic(thread_t) s_transaction_thread = THREAD_NULL;
static detour_operation* s_pending_operations_head = nullptr;
static detour_pending_thread* s_pending_threads_head = nullptr;
@ -122,7 +202,9 @@ mach_error_t detour_transaction_abort()
// Restore all the page permissions.
const mach_port_t port = mach_task_self();
for (detour_operation* operation = s_pending_operations_head; operation != nullptr;) {
DETOUR_CHECK(mach_vm_protect(port, (mach_vm_address_t)operation->target, operation->trampoline->restore_code_size, false, operation->perm));
DETOUR_CHECK(
mach_vm_protect(port, (mach_vm_address_t)operation->target, operation->trampoline->restore_code_size, false,
operation->perm));
if (operation->kind == detour_operation_kind_attach) {
if (operation->trampoline) {
@ -154,3 +236,169 @@ mach_error_t detour_transaction_abort()
return err_none;
}
mach_error_t detour_transaction_commit()
{
return detour_transaction_commit_ex(nullptr);
}
mach_error_t detour_transaction_commit_ex(detour_func_t** out_failed_target)
{
if (out_failed_target != NULL) {
*out_failed_target = s_pending_error_pointer;
}
if (s_transaction_thread != mach_thread_self()) {
return detour_err_wrong_thread;
}
// If any of the pending operations failed, then we abort the whole transaction.
if (s_pending_error != err_none) {
DETOUR_BREAK();
detour_transaction_abort();
return s_pending_error;
}
// Insert or remove each of the detours.
for (detour_operation* operation = s_pending_operations_head; operation != nullptr; operation = operation->next) {
if (operation->kind == detour_operation_kind_detach) {
memcpy(operation->target, operation->trampoline->restore_code, operation->trampoline->restore_code_size);
#ifdef DETOURS_ARM64
*operation->pointer = operation->target;
#endif
} else {
DETOUR_TRACE(("detours: trampoline=%p, ptr_remain=%p, ptr_detour=%p, restore_code_size=%u\n",
operation->trampoline,
operation->trampoline->ptr_remain,
operation->trampoline->ptr_detour,
operation->trampoline->restore_code_size));
DETOUR_TRACE(("detours: target=%p: "
"%02x %02x %02x %02x "
"%02x %02x %02x %02x "
"%02x %02x %02x %02x [before]\n",
operation->target,
operation->target[0], operation->target[1], operation->target[2], operation->target[3],
operation->target[4], operation->target[5], operation->target[6], operation->target[7],
operation->target[8], operation->target[9], operation->target[10], operation->target[11]));
#ifdef DETOURS_ARM64
uint8_t* code = internal_detour_gen_jmp_indirect(operation->target,
(uint64_t*)&(operation->trampoline->ptr_detour));
code = internal_detour_gen_brk(code, operation->trampoline->ptr_remain);
*operation->pointer = operation->trampoline->code;
#endif // DETOURS_ARM64
DETOUR_TRACE(("detours: target=%p: "
"%02x %02x %02x %02x "
"%02x %02x %02x %02x "
"%02x %02x %02x %02x [after]\n",
operation->target,
operation->target[0], operation->target[1], operation->target[2], operation->target[3],
operation->target[4], operation->target[5], operation->target[6], operation->target[7],
operation->target[8], operation->target[9], operation->target[10], operation->target[11]));
DETOUR_TRACE(("detours: trampoline=%p: "
"%02x %02x %02x %02x "
"%02x %02x %02x %02x "
"%02x %02x %02x %02x\n",
operation->trampoline,
operation->trampoline->code[0], operation->trampoline->code[1],
operation->trampoline->code[2], operation->trampoline->code[3],
operation->trampoline->code[4], operation->trampoline->code[5],
operation->trampoline->code[6], operation->trampoline->code[7],
operation->trampoline->code[8], operation->trampoline->code[9],
operation->trampoline->code[10], operation->trampoline->code[11]));
}
}
// Update any suspended threads.
for (detour_pending_thread* thread = s_pending_threads_head; thread != nullptr; thread = thread->next) {
arm_thread_state64_t threadState;
mach_msg_type_number_t threadStateCnt = ARM_THREAD_STATE64_COUNT;
kern_return_t error = thread_get_state(thread->thread, ARM_THREAD_STATE64, (thread_state_t)&threadState,
&threadStateCnt);
if (error != err_none) {
DETOUR_BREAK();
continue;
}
const uintptr_t pc = arm_thread_state64_get_pc(threadState);
for (detour_operation* op = s_pending_operations_head; op != nullptr; op = op->next) {
switch (op->kind) {
case detour_operation_kind_attach: {
const uintptr_t targetAddr = (uintptr_t)op->target;
if (pc >= targetAddr && pc < targetAddr + op->trampoline->restore_code_size) {
uintptr_t new_pc = (uintptr_t)op->trampoline;
new_pc += internal_detour_align_from_target(op->trampoline, pc - targetAddr);
printf("detours: thread %u was at 0x%" PRIXPTR ", moved to 0x%" PRIXPTR "\n", thread->thread,
pc,
new_pc);
arm_thread_state64_set_pc_fptr(threadState, new_pc);
thread_set_state(thread->thread, ARM_THREAD_STATE64, (thread_state_t)&threadState,
ARM_THREAD_STATE64_COUNT);
}
break;
}
case detour_operation_kind_detach: {
const uintptr_t trampAddr = (uintptr_t)op->trampoline;
if (pc >= trampAddr && pc < trampAddr + sizeof(*op->trampoline)) {
uintptr_t new_pc = (uintptr_t)op->target;
new_pc += internal_detour_align_from_trampoline(op->trampoline, pc - trampAddr);
printf("detours: thread %u was at 0x%" PRIXPTR ", moved to 0x%" PRIXPTR "\n", thread->thread,
pc,
new_pc);
arm_thread_state64_set_pc_fptr(threadState, new_pc);
thread_set_state(thread->thread, ARM_THREAD_STATE64, (thread_state_t)&threadState,
ARM_THREAD_STATE64_COUNT);
}
break;
}
}
}
}
// Restore all the page permissions
bool freed_trampoline = false;
const mach_port_t port = mach_task_self();
for (detour_operation* operation = s_pending_operations_head; operation != nullptr;) {
DETOUR_CHECK(
mach_vm_protect(port, (mach_vm_address_t)operation->target, operation->trampoline->restore_code_size, false,
operation->perm));
if (operation->kind == detour_operation_kind_detach && operation->trampoline) {
internal_detour_free_trampoline(operation->trampoline);
operation->trampoline = nullptr;
freed_trampoline = true;
}
detour_operation* next = operation->next;
free(operation);
operation = next;
}
s_pending_operations_head = nullptr;
// Free any trampoline regions that are now unused.
if (freed_trampoline && !s_retain_regions) {
internal_detour_free_unused_trampoline_regions();
}
// Make sure the trampoline pages are no longer writable.
internal_detour_runnable_trampoline_regions();
// Resume any suspended threads.
for (detour_pending_thread* thread = s_pending_threads_head; thread != nullptr;) {
// There is nothing we can do if this fails.
DETOUR_CHECK(thread_resume(thread->thread));
detour_pending_thread* next = thread->next;
free(thread);
thread = next;
}
s_pending_threads_head = nullptr;
s_transaction_thread = THREAD_NULL;
if (out_failed_target) {
*out_failed_target = s_pending_error_pointer;
}
return s_pending_error;
}