win-capture: Add inject-helper program

This program simply injects a library in to the target progress using
SetWindowsHookEx.

plugins/win-capture/CMakeLists.txt

@@ -25,3 +25,4 @@ target_link_libraries(win-capture
 install_obs_plugin_with_data(win-capture data)
 
 add_subdirectory(get-graphics-offsets)
+add_subdirectory(inject-helper)

plugins/win-capture/inject-helper/CMakeLists.txt

@@ -0,0 +1,25 @@
+project(inject-helper)
+
+set(inject-helper_HEADERS
+	../obfuscate.h)
+
+set(inject-helper_SOURCES
+	../obfuscate.c
+	inject-helper.c)
+
+add_executable(inject-helper
+	${inject-helper_SOURCES})
+
+target_link_libraries(inject-helper)
+
+if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+	set(_output_suffix "64")
+else()
+	set(_output_suffix "32")
+endif()
+
+set_target_properties(inject-helper
+	PROPERTIES
+		OUTPUT_NAME "inject-helper${_output_suffix}")
+
+install_obs_datatarget(inject-helper "obs-plugins/win-capture")

plugins/win-capture/inject-helper/inject-helper.c

@@ -0,0 +1,89 @@
+#include <stdio.h>
+#include <windows.h>
+#include <shellapi.h>
+#include <stdbool.h>
+#include "../obfuscate.h"
+
+static void load_debug_privilege(void)
+{
+	const DWORD flags = TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY;
+	bool success = false;
+	TOKEN_PRIVILEGES tp;
+	HANDLE token;
+	LUID val;
+
+	if (!OpenProcessToken(GetCurrentProcess(), flags, &token)) {
+		return;
+	}
+
+	if (!!LookupPrivilegeValue(NULL, SE_DEBUG_NAME, &val)) {
+		tp.PrivilegeCount = 1;
+		tp.Privileges[0].Luid = val;
+		tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+
+		success = !!AdjustTokenPrivileges(token, false, &tp,
+				sizeof(tp), NULL, NULL);
+	}
+
+	CloseHandle(token);
+}
+
+typedef HHOOK (WINAPI *set_windows_hook_ex_t)(int, HOOKPROC, HINSTANCE, DWORD);
+
+static int inject_library_safe(DWORD thread_id, const char *dll)
+{
+	HMODULE user32 = GetModuleHandleW(L"USER32");
+	set_windows_hook_ex_t set_windows_hook_ex;
+	HMODULE lib = LoadLibraryA(dll);
+	LPVOID proc;
+	HHOOK hook;
+	size_t i;
+
+	if (!lib || !user32) {
+		return -3;
+	}
+
+#ifdef _WIN64
+	proc = GetProcAddress(lib, "dummy_debug_proc");
+#else
+	proc = GetProcAddress(lib, "_dummy_debug_proc@12");
+#endif
+
+	if (!proc) {
+		return -4;
+	}
+
+	set_windows_hook_ex = get_obfuscated_func(user32, "[bs^fbkmwuKfmfOvI",
+			0xEAD293602FCF9778ULL);
+
+	hook = set_windows_hook_ex(WH_GETMESSAGE, proc, lib, thread_id);
+	if (!hook) {
+		return -5;
+	}
+
+	for (i = 0; i < 20; i++)
+		PostThreadMessage(thread_id, WM_USER + 432, 0, (LPARAM)hook);
+	Sleep(1000);
+	for (i = 0; i < 20; i++)
+		PostThreadMessage(thread_id, WM_USER + 432, 0, (LPARAM)hook);
+	Sleep(1000);
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	DWORD thread_id;
+
+	load_debug_privilege();
+
+	if (argc < 3) {
+		return -1;
+	}
+
+	thread_id = strtol(argv[2], NULL, 10);
+	if (thread_id == 0) {
+		return -2;
+	}
+
+	return inject_library_safe(thread_id, argv[1]);
+}