XInput User Index to Device Instance ID PoC

Crude example project demoing how one can use API hooking CreateFile to reverse-lookup the device instance ID of the device behind a given user/player index.

Since the XInput API is deliberately kept simple and opaque, we need to get creative if we need the Player index to device association. The idea is as follows:

• We hook CreateFile since any XInput DLL internally enumerates and opens the desired instance of the device running under XUSB22.sys
  • This grants us easy access to the device path/symbolic link we will need later on
• Call XInputGetCapabilities with the desired user index to look up
  • This triggers our hook and calls the detoured function instead, supplying the symbolic link as the lpFileName parameter.
  • Within the detoured function, we can use CM_Get_Device_Interface_Property from CfgMgr32.h to query for DEVPKEY_Device_InstanceId.
  • Now we got the local machine unique device instance ID of the XUSB/XInput controller device 😃

Screenshots