在 C++ 中将汇编转换为机器代码

Question

我寻找任何库或函数来将一串汇编代码转换为机器代码，如下所示：

char asmString[] = {"mov eax,13H"};
byte[] output; // array of byte
output = asm2mach(asmString); // {0xB8, 0x13, 0x00, 0x00, 0x00}

动机是在程序中注入机器码来调用asm函数。这次注入主要有3个步骤：VirtualAllocEx、WriteProcessMemory和CreateRemoteThread。下面是代码：

bool injectAsm(const char* exeName,const byte* code, int size) 
{ 
    LPVOID allocAddr = NULL;
    HANDLE ThreadProcess = NULL;
    HANDLE hProcess = OpenProcessEasy(exeName);

    allocAddr = VirtualAllocEx(hProcess, NULL, size, MEM_COMMIT, PAGE_READWRITE);
    if(allocAddr){
        if(WriteProcessMemory(hProcess, allocAddr, code, size, NULL)) {
            ThreadProcess = CreateRemoteThread(hProcess, NULL, 0, (LPTHREAD_START_ROUTINE)allocAddr, NULL, 0, NULL);
            WaitForSingleObject(ThreadProcess, INFINITE);
            VirtualFreeEx(hProcess,allocAddr, 0, MEM_RELEASE);
            CloseHandle(ThreadProcess);
            return true;
        }
    }
    if(allocAddr){
        VirtualFreeEx(hProcess, allocAddr, 0, MEM_RELEASE);
    }
    return false;
}

int main()
{
    byte code[] = {0xB8, 0x10, 0xED, 0x4A, 0x00, 0xFF, 0xD0, 0xC3, 0x90};
    injectAsm("game.exe",code,sizeof(code));
    system("pause");
    return 0;
} 

Answer 1

我建议同时使用AsmJit和AsmTK。AsmTK 是一个新项目，它使用 AsmJit 作为工具包并在其之上添加附加功能。请注意，目前 AsmTK 要求 asmjit:next 分支工作，因为这是一个新功能。

这是一个使用 AsmTK 解析一些 asm 的最小示例：

#include <stdio.h>
#include <stdlib.h>
#include <asmtk/asmtk.h>

using namespace asmjit;
using namespace asmtk;

static const char someAsm[] =
  "test eax, eax\n"
  "jz L1\n"
  "mov eax, ebx\n"
  "mov eax, 0xFFFFFFFF\n"
  "pand mm0, mm1\n"
  "paddw xmm0, xmm1\n"
  "vpaddw ymm0, ymm1, ymm7\n"
  "vaddpd zmm0 {k1}{z}, zmm1, [rax] {1tox}\n"
  "L1:\n";

int main(int argc, char* argv[]) {
  CodeHolder code;
  // Here select the target architecture - either X86 or X64.
  code.init(CodeInfo(Arch::kTypeX64));

  X86Assembler a(&code);
  AsmParser p(&a);

  Error err = p.parse(someAsm);
  if (err) {
    printf("ERROR: %0.8x (%s)\n", err, DebugUtils::errorAsString(err));
    return 1;
  }

  // The machine-code is now stored in CodeHolder's first section:
  code.sync();
  CodeBuffer& buffer = code.getSection(0)->buffer;

  // You can do whatever you need with the buffer:
  uint8_t* data = buffer.data;
  size_t length = buffer.length;

  return 0;
}

AsmJit 使用 JitRuntime 分配可执行内存并将生成的机器代码重定位到其中。但是，AsmJit 的虚拟内存分配器可以使用 来创建hProcess，它可以是您的远程进程句柄，因此它也可以为该进程分配内存。这是一个如何完成的小例子：

bool addToRemote(HPROCESS hRemoteProcess, CodeHolder& code) {
  // VMemMgr is AsmJit's low-level VM manager.
  VMemMgr vm(hRemoteProcess);

  // This will tell `vm` to not destroy allocated blocks when it
  // gets destroyed.
  vm.setKeepVirtualMemory(true);

  // Okay, suppose we have the CodeHolder from previous example.
  size_t codeSize = code.getCodeSize();

  // Allocate a permanent memory of `hRemoteProcess`.
  uint64_t remoteAddr = (uint64_t)
    vm.alloc(codeSize, VMemMgr::kAllocPermanent);

  // Temporary buffer for relocation.
  uint8_t* tmp = ::malloc(code.getCodeSize());
  if (!tmp) return false;

  // First argument is where to relocate the code (it must be
  // current's process memory), second argument is the base
  // address of the relocated code - it's the remote process's
  // memory. We need `tmp` as it will temporarily hold code
  // that we want to write to the remote process.
  code.relocate(tmp, remoteAddr);

  // Now write to the remote process.
  SIZE_T bytesWritten;
  BOOL ok = WriteProcessMemory(
    hRemoteProcess, (LPVOID)remoteMem, tmp, codeSize, &bytesWritten);

  // Release temporary resources.
  ::free(tmp);

  // Now the only thing needed is the CreateRemoteThread thingy...
  return ok;
}

我建议将此类功能包装到新的 RemoteRuntime 中，使其成为单个函数调用的问题，如果需要，我可以提供帮助。