notcarlton / csinternalsample

A sample that shows the usage of internal C# clients.

CsInternalSample

This sample uses the power of C# and .NET NativeAOT to create an injectable client.

Since I didn't find a known way to execute code in C# when injected, I had to make this client depended from another C++ DLL (which gets injected first). This C++ DLL then loads our C# DLL and calls the Load_ function which we exported as _Load_CsInternalClient.

[UnmanagedCallersOnly(EntryPoint = "_Load_CsInternalClient", CallConvs = new[] { typeof(CallConvStdcall) })]
internal static void Load_()
{
    ...
}

Building

Make sure to clone this repo using the --recursive flag:

git clone --recursive https://github.com/CXCubeHD/CsInternalSample

You can create the NativeAOT C# DLL (CsInternalClient) using:

dotnet publish -r win-x64 -c Release

If it doesn't say Generating compatible native code. To optimize for size or speed, visit https://aka.ms/OptimizeNativeAOT then you probably did something wrong.

The compiled DLL should appear at this location: .\CsInternalClient\bin\Release\net7.0-windows10.0.22621.0\win-x64\native

Then tell the C++ DLL where our DLL is located by editing this file: .\CsInternalLoader\src\CsInternalLoader-impl\config\config.cc

// TODO: Enter the path of your CsInternalClient DLL
inline chr::wstr CsInternalClientPath =
	L"PATH TO NativeAOT C# DLL";

If you are trying to inject those DLLs into an UWP app then make sure they both have the required file permissions.

Lastly compile the C++ DLL (CsInternalLoader) using CMake.

---

That's it now you can inject it!

License

The license can be found under LICENSE.md.

Please note that currently the license is very strict so please make sure to read it.

Changes License to MIT