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Code Issues Activity

Clean Linux Detour

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This commit is contained in:
Nemirtingas 2019-09-01 23:21:13 +02:00
parent b9cd9ae6c2
commit 95e87eb832
2 changed files with 9 additions and 28 deletions
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7
overlay_experimental/linux/Linux_Detour.cpp
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@ -13,8 +13,8 @@
//------------------------------------------------------------------------------//
// Helper funcs
//------------------------------------------------------------------------------//
constexpr static auto relative_jump_size = 5;
constexpr static auto relative_addr_jump_size = sizeof(int32_t);
constexpr static auto relative_jump_size = 1 + relative_addr_jump_size;
constexpr static auto absolute_jump_size = 6;
struct
@ -134,14 +134,12 @@ struct trampoline_x86_t
uint8_t trampolineBytes[16+relative_jump_size]; // trampoline + original function opcodes
uint8_t hookJump[relative_jump_size]; // jump to hook addr, needed because of relative jump overflow
uint8_t nOriginalBytes; // number of original function bytes bkp
uint8_t originalBytes[16]; // original function bytes
};
typedef trampoline_x86_t trampoline_t;
struct trampoline_region_t
{
uint32_t header;
uint8_t numTrampolines; // current trampolines allocated
trampoline_t *trampolines_start; // start pointer of current region trampolines
trampoline_t *next_free_trampoline; // next free trampoline in region
@ -492,7 +490,7 @@ int Linux_Detour::transaction_commit()
res = mprotect(originalFunctionPage, page_size()*2, PROT_READ|PROT_WRITE|PROT_EXEC);
// Write the original opcodes
std::copy(trampoline->originalBytes, trampoline->originalBytes+trampoline->nOriginalBytes,
std::copy(trampoline->trampolineBytes, trampoline->trampolineBytes+trampoline->nOriginalBytes,
reinterpret_cast<uint8_t*>(*ppOriginalFunc));
// Remove write permission
@ -582,7 +580,6 @@ int Linux_Detour::hook_func(void** ppOriginalFunc, void* _hook)
gen_immediate_jump(trampoline->hookJump, hook);
// Copy original opcodes
trampoline->nOriginalBytes = code_len;
std::copy((uint8_t*)pOriginalFunc, ((uint8_t*)pOriginalFunc)+code_len, trampoline->originalBytes);
std::copy((uint8_t*)pOriginalFunc, ((uint8_t*)pOriginalFunc)+code_len, pTrampolineCode);
pTrampolineCode += code_len;
// Create the relative jmp to original (function + backed up opcodes)

30
overlay_experimental/linux/Linux_Detour.h
View file

@ -1,32 +1,16 @@
#ifndef LINUX_DETOUR_H
#define LINUX_DETOUR_H
#include <sys/syscall.h>
#include <unistd.h>
#include <pthread.h>
#include <thread>
class Linux_Detour
namespace Linux_Detour
{
public:
static int update_thread(pthread_t thread_id);
static int transaction_begin();
static int transaction_abort();
static int transaction_commit();
static int hook_func(void** ppOriginalFunc, void* _hook);
static int unhook_func(void** ppOriginalFunc, void* _hook);
private:
static int hook_func_abs(void** ppOriginalFunc, void* _hook);
static int hook_func_rel(void** ppOriginalFunc, void* _hook);
Linux_Detour() = delete;
Linux_Detour(Linux_Detour const&) = delete;
Linux_Detour(Linux_Detour &&) = delete;
Linux_Detour& operator=(Linux_Detour const&) = delete;
Linux_Detour& operator=(Linux_Detour &&) = delete;
int update_thread(pthread_t thread_id);
int transaction_begin();
int transaction_abort();
int transaction_commit();
int hook_func(void** ppOriginalFunc, void* _hook);
int unhook_func(void** ppOriginalFunc, void* _hook);
};
extern "C" void *elf_hook(char const *library_filename, void const *library_address, char const *function_name, void const *substitution_address);
#endif // LINUX_DETOUR_H