YAHL (Yet-Another-Hooking-Library)

The world desperately needed another hooking library, so here it is. YAHL is more robust than most other hooking libraries. Supporting inline code cave hooking instead of IAT hooking.

Features

• Only supports x86 binary hooking currently
• Not calling the original function at all
• Calling the original function with a different argument
• Different calling conventions of original functions (stdcall, cdecl, fastcall, and thiscall supported)

Usage

A full working example is provided in the ./YAHL/src/hook_example.cpp file which compiles to a injectable DLL. (See below for how to compile and run the example.)

The gist of how to use YAHL is the following:

1. Create a YAHL::Detour object and pass the address of the function you want to hook, detour function, and how many bytes to overwrite.
2. Create a function which mirrors the signature of the original function to hook, but has an additional parameter at the beginning of type YAHL::Detour &detour. (e.g. If your original function signature is bool __cdecl MyFunction(int a, int b), then your detour function signature should be bool __cdecl MyFunctionDetour(YAHL::Detour &detour, int a, int b)).
3. Call YAHL::Detour::Enable() to hook the function.
4. If the program terminates, it's likely you have have an issue with how many bytes you are overwriting (You must have at least 5 bytes to assemble a long jmp but it can be more), or you have the incorrect signature/calling convention for the detour/original function.

Setup and example tests

1. Compile the HookMe and YAHL projects.
2. Run the Release version of HookMe.exe, observe the output.
3. Run Inject32.bat in the ./examples directory, this will inject the YAHL example dll into the HookMe process.
4. Observe the changed output of HookMe.exe.