76 lines
2.2 KiB
C++
76 lines
2.2 KiB
C++
#include <Windows.h>
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#include <util/hooklib.hpp>
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#include <vendor/hde.hpp>
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namespace util {
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constexpr uint8_t target_shellcode[] = {
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0x8D, 0x64, 0x24, 0xFC, // lea esp, [esp-0x4]
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0xC7, 0x04, 0x24, 0xFF, 0xFF, 0xFF, 0xFF, // mov DWORD PTR [esp], ADDRESS
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0xC3 // ret
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};
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constexpr uint8_t tramp_shellcode[] = {
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0x68, 0xFF, 0xFF, 0xFF, 0xFF, // push imm32
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0xC3, // ret
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};
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bool Hook::enable(uintptr_t target, uintptr_t detour) {
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hde32s hde_state;
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while (_bytes < sizeof(target_shellcode)) {
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_bytes += hde32_disasm((const void *) (target + _bytes), &hde_state);
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if (hde_state.opcode == 0xC3) {
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_bytes = 0;
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return false;
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}
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}
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auto tramp = VirtualAlloc(nullptr, _bytes + sizeof(tramp_shellcode), MEM_COMMIT, PAGE_EXECUTE_READWRITE);
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if (!tramp) {
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_bytes = 0;
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return false;
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}
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unsigned long old_prot;
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VirtualProtect((void *) target, _bytes, PAGE_EXECUTE_READWRITE, &old_prot);
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_target = target;
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_detour = detour;
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_tramp = (uintptr_t) tramp;
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memcpy((uint8_t *) _tramp, (const uint8_t *) _target, _bytes);
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memcpy((uint8_t *) _tramp + _bytes, tramp_shellcode, sizeof(tramp_shellcode));
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memcpy((uint8_t *) _target, target_shellcode, sizeof(target_shellcode));
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*(uintptr_t *) (_target + 7) = _detour;
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*(uintptr_t *) (_tramp + _bytes + 1) = _target + _bytes;
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VirtualProtect((void *) target, _bytes, old_prot, &old_prot);
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return true;
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}
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void Hook::disable() {
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if (!_bytes)
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return;
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unsigned long old_prot;
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VirtualProtect((void *) _target, _bytes, PAGE_EXECUTE_READWRITE, &old_prot);
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memcpy((uint8_t *) _target, (const uint8_t *) _tramp + _bytes, _bytes);
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VirtualFree((void *) _tramp, 0, MEM_RELEASE);
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VirtualProtect((void *) _target, _bytes, old_prot, &old_prot);
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_bytes = 0;
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_target = 0;
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_detour = 0;
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_tramp = 0;
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}
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} // namespace util
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