C# dll 注入不加载 dll答案

【问题标题】：C# dll injection not loading dllC# dll 注入不加载 dll
【发布时间】：2020-05-06 16:48:14
【问题描述】：

我知道 stackoverflow 上有一些类似的问题，但没有一个能解决我的问题。

所以我正在编写一个用于低级进程间操作的 c# 框架，包括 dll 注入功能。

在调用我的注入器之前，我已经使用OpenProcess() 和PROCESS_ALL_ACCESS 权限附加到目标进程（在本例中为notepad++.exe）。以下是我的注入器代码（我知道由于所有的调试打印，可读性受到了很大影响）：

public void Inject(string dllName, bool printDebugInfo)
{
    // Check if we are attached to the process.
    target.Assertions.AssertProcessAttached();
    target.Assertions.AssertInjectionPermissions();

    // searching for the address of LoadLibraryA and storing it in a pointer
    IntPtr kernel32Handle = WinAPI.GetModuleHandle("kernel32.dll");
    if (kernel32Handle == IntPtr.Zero)
    {
        uint errorCode = WinAPI.GetLastError();
        throw new Win32Exception((int)errorCode, "Encountered error " + errorCode.ToString() + " (0x" + errorCode.ToString("x") + ") - FATAL: Could not get handle of kernel32.dll: was NULL.");
    }
    UIntPtr loadLibraryAddr = WinAPI.GetProcAddress(kernel32Handle, "LoadLibraryA");
    if (loadLibraryAddr == UIntPtr.Zero)
    {
        uint errorCode = WinAPI.GetLastError();
        throw new Win32Exception((int)errorCode, "Encountered error " + errorCode.ToString() + " (0x" + errorCode.ToString("x") + ") - FATAL: Could not get address of LoadLibraryA: was NULL.");
    }
    HelperMethods.Debug("LoadLibraryA is at 0x" + loadLibraryAddr.ToUInt64().ToString("x"), printDebugInfo);

    // alocating some memory on the target process - enough to store the name of the dll
    // and storing its address in a pointer
    uint size = (uint)((dllName.Length + 1) * Marshal.SizeOf(typeof(char)));
    IntPtr allocMemAddress = WinAPI.VirtualAllocEx(target.Handle, IntPtr.Zero, size, (uint)Permissions.MemoryPermission.MEM_COMMIT | (uint)Permissions.MemoryPermission.MEM_RESERVE, (uint)Permissions.MemoryPermission.PAGE_READWRITE);
    HelperMethods.Debug("Allocated memory at 0x" + allocMemAddress.ToInt64().ToString("x"), printDebugInfo);

    int bytesWritten = 0;
    // writing the name of the dll there
    byte[] buffer = new byte[size];
    byte[] bytes = Encoding.ASCII.GetBytes(dllName);
    Array.Copy(bytes, 0, buffer, 0, bytes.Length);
    buffer[buffer.Length - 1] = 0;
    bool success = WinAPI.WriteProcessMemory((uint)target.Handle, allocMemAddress.ToInt64(), buffer, size, ref bytesWritten);
    if (success)
    {
        HelperMethods.Debug("Successfully wrote \"" + dllName + "\" to 0x" + allocMemAddress.ToInt64().ToString("x"), printDebugInfo);
    }
    else
    {
        HelperMethods.Debug("FAILED to write dll name!", printDebugInfo);
    }
    // creating a thread that will call LoadLibraryA with allocMemAddress as argument
    HelperMethods.Debug("Injecting dll ...", printDebugInfo);
    IntPtr threadHandle = WinAPI.CreateRemoteThread(target.Handle, IntPtr.Zero, 0, loadLibraryAddr, allocMemAddress, 0, out IntPtr threadId);
    HelperMethods.Debug("CreateRemoteThread returned the following handle: 0x" + threadHandle.ToInt32().ToString("x"), printDebugInfo);
    uint errCode = WinAPI.GetLastError();
    if (threadHandle == IntPtr.Zero)
    {
        throw new Win32Exception((int)errCode, "Encountered error " + errCode.ToString() + " (0x" + errCode.ToString("x") + ") - FATAL: CreateRemoteThread returned NULL pointer as handle.");
    }
    Console.WriteLine("CreateRemoteThread threw errorCode 0x" + errCode.ToString("x"));
    Console.WriteLine("Currently the following modules are LOADED:");
    ProcessModuleCollection processModules = target.Process.Modules;
    foreach (ProcessModule module in processModules)
    {
        Console.WriteLine("  - " + module.FileName);
    }
    uint waitExitCode = WinAPI.WaitForSingleObject(threadHandle, 10 * 1000);
    HelperMethods.Debug("Waiting for thread to exit ...", printDebugInfo);
    HelperMethods.Debug("WaitForSingleObject returned 0x" + waitExitCode.ToString("x"), printDebugInfo);
    Thread.Sleep(1000);
    Console.WriteLine("Currently the following modules are LOADED:");
    processModules = target.Process.Modules;
    foreach (ProcessModule module in processModules)
    {
        Console.WriteLine("  - " + module.FileName);
    }
    success = WinAPI.GetExitCodeThread(threadHandle, out uint exitCode);
    if (!success)
    {
        uint errorCode = WinAPI.GetLastError();
        throw new Win32Exception((int)errorCode, "Encountered error " + errorCode.ToString() + " (0x" + errorCode.ToString("x") + ") - FATAL: Non-zero exit code of GetExitCodeThread.");
    }
    Console.WriteLine("Currently the following modules are LOADED:");
    processModules = target.Process.Modules;
    foreach (ProcessModule module in processModules)
    {
        Console.WriteLine("  - " + module.FileName);
    }
    HelperMethods.Debug("Remote thread returned 0x" + exitCode.ToString("x"), printDebugInfo);
    success = WinAPI.CloseHandle(threadHandle);
    if (!success)
    {
        uint errorCode = WinAPI.GetLastError();
        throw new Win32Exception((int)errorCode, "Encountered error " + errorCode.ToString() + " (0x" + errorCode.ToString("x") + ") - FATAL: Failed calling CloseHandle on 0x" + threadHandle.ToInt64().ToString("x") + ".");
    }
    HelperMethods.Debug("Called CloseHandle on 0x" + threadHandle.ToInt64().ToString("x") + ".", printDebugInfo);
    success = WinAPI.VirtualFreeEx(target.Handle, allocMemAddress, 0, 0x8000);
    if (!success)
    {
        uint errorCode = WinAPI.GetLastError();
        throw new Win32Exception((int)errorCode, "Encountered error " + errorCode.ToString() + " (0x" + errorCode.ToString("x") + ") - FATAL: Failed calling VirtualFreeEx on 0x" + allocMemAddress.ToInt64().ToString("x") + ".");
    }
    HelperMethods.Debug("Released all previously allocated resources!", printDebugInfo);
}

按照微软官方文档的规定调用所有 WinAPI 函数（三重检查）。

我的代码如下调用

Target target = Target.CreateFromName("notepad++");
target.Attach(Permissions.ProcessPermission.PROCESS_ALL_ACCESS);
target.Injector.Inject(@"L:\Programming\C\test\newdll.dll",true);

Target 类的完整源代码在 GitHub 上，但与此问题无关。

这里最有趣的可能是newdll.dll，它是用原生 C 编写的，如下所示：

#include<Windows.h>
#include<stdbool.h>
__declspec(dllexport) bool WINAPI DllMain(HINSTANCE hInstDll, DWORD fdwReason, LPVOID lpvReserved)
{
    switch (fdwReason)
    {
        case DLL_PROCESS_ATTACH:
        {
            break;
        }

        case DLL_PROCESS_DETACH:
        {
            break;
        }

        case DLL_THREAD_ATTACH:
        {
            break;
        }

        case DLL_THREAD_DETACH:
        {
            break;
        }
    }
    return true;
}

这段代码显然没有多大作用，但是由于从 DllMain 生成消息框之类的东西显然被认为是“坏的”，所以我就这样离开了它。但是，如果注入有效，则 dll 将列在 Process.Modules 中（它不是）。

但是，在运行我的代码时，我会从所有调试打印中得到以下输出：

LoadLibraryA is at 0x778f60b0
Allocated memory at 0x9c0000
Successfully wrote "L:\Programming\C\test\newdll.dll" to 0x9c0000
Injecting dll ...
CreateRemoteThread returned the following handle: 0x22c
CreateRemoteThread threw errorCode 0x0
Currently the following modules are LOADED:
  - J:\TOOLS\Notepad++\notepad++.exe
  - C:\Windows\SYSTEM32\ntdll.dll
  - C:\Windows\SYSTEM32\wow64.dll
  - C:\Windows\SYSTEM32\wow64win.dll
  - C:\Windows\SYSTEM32\wow64cpu.dll
Waiting for thread to exit ...
WaitForSingleObject returned 0x0
Currently the following modules are LOADED:
  - J:\TOOLS\Notepad++\notepad++.exe
  - C:\Windows\SYSTEM32\ntdll.dll
  - C:\Windows\SYSTEM32\wow64.dll
  - C:\Windows\SYSTEM32\wow64win.dll
  - C:\Windows\SYSTEM32\wow64cpu.dll
Currently the following modules are LOADED:
  - J:\TOOLS\Notepad++\notepad++.exe
  - C:\Windows\SYSTEM32\ntdll.dll
  - C:\Windows\SYSTEM32\wow64.dll
  - C:\Windows\SYSTEM32\wow64win.dll
  - C:\Windows\SYSTEM32\wow64cpu.dll
Remote thread returned 0x0
Called CloseHandle on 0x22c.
Released all previously allocated resources!
Press any key to continue . . .

可以看出，除了newdll.dll 从未加载，因为它没有显示在Process.Modules 中加载的模块中，没有错误代码或任何迹象表明注入确实出错了。

那么我的代码有什么问题？

快速概览：我确实遵循以下程序：

OpenProcess() 与 PROCESS_ALL_ACCESS
GetModuleHandle("kernel32.dll")
GetProcAddress(kernel32Handle, "LoadLibraryA")
VirtualAllocEx(...) 和 WriteProcessMemory() 写我的 dll 名称和路径。
CreateRemoteThread() 加载dll
WaitForSingleObject() 等待加载dll
释放之前分配的所有资源

【问题讨论】：

您的注入器应用程序需要与目标应用程序具有相同的位数才能匹配 LoadLibrary 地址。当然，dll 的位数也需要匹配。
谢谢。你就这样解决了 2 周的调试问题。这正是问题所在。我正在编译为 64 位，目标进程是 32 位：|
很高兴我能帮上忙 :)

标签： c# c .net dll dll-injection

【解决方案1】：

正如正确指出的那样，这种注入技术仅在从 32 位进程 --> 32 位进程或从 64 位进程 --> 64 位进程注入时才有效。我正在将我的代码编译为 64 位可执行文件，试图将我的 dll 注入 32 位 notepad++.exe。

我还必须调整 WriteProcessMemory 调用以符合 32 位内存空间。所以从bool success = WinAPI.WriteProcessMemory((uint)target.Handle, allocMemAddress.ToInt64(), buffer, size, ref bytesWritten); 更改为bool success = WinAPI.WriteProcessMemory((uint)target.Handle, allocMemAddress.ToInt32(), buffer, size, ref bytesWritten); 就成功了。

【讨论】：