Overlay: Resolve undefined behavior

* Now that we no longer do anything when unloading the overlay DLL,
remove the injection of FreeLibrary. This also drops some undefined
behavior.
** If we inject into rendering (D3Dxx.cpp) we hold a self-reference to
prevent to ever be unloaded. For this case, there is no issue as the
hooks will always exist.
** In case of no rendering-injection, our module can actually be
unloaded. In that case, MyFreeLibrary would call the original function
which in turn would lead to a call to DllMain with DLL_PROCESS_DETACH,
at which point we restore the hooks to their original equivalents in
dllmainProcDetach.
However, afterwards, execution returns to our MyFreeLibrary function,
whichs code is no longer the code we began executing.
** This also leads to the question whether the non-trampoline hooking
ever worked/even works. We restore, call the original (which is already
code that no longer exists) and then inject again.

1 files changed, 0 insertions, 18 deletions

diff --git a/overlay/lib.cpp b/overlay/lib.cpp
index 9f63771dd..bf952cc00 100644
--- a/overlay/lib.cpp
+++ b/overlay/lib.cpp
@@ -45,7 +45,6 @@ static BOOL bBlackListed = FALSE;
 
 static HardHook hhLoad;
 static HardHook hhLoadW;
-static HardHook hhFree;
 
 static SharedData *sd = NULL;
 
@@ -385,20 +384,6 @@ static HMODULE WINAPI MyLoadLibraryW(const wchar_t *lpFileName) {
 	return h;
 }
 
-typedef BOOL(__stdcall *FreeLibraryType)(HMODULE hModule);
-static BOOL WINAPI MyFreeLibrary(HMODULE hModule) {
-	ods("Lib: MyFreeLibrary %p", hModule);
-
-	//TODO: Move logic to HardHook.
-	// Call base without active hook in case of no trampoline.
-	FreeLibraryType oFreeLibrary = (FreeLibraryType) hhFree.call;
-	hhFree.restore();
-	BOOL r = oFreeLibrary(hModule);
-	hhFree.inject();
-
-	return r;
-}
-
 static LRESULT CALLBACK CallWndProc(int nCode, WPARAM wParam, LPARAM lParam) {
 	return CallNextHookEx(hhookWnd, nCode, wParam, lParam);
 }
@@ -547,7 +532,6 @@ static void dllmainProcAttach(char *procname) {
 		// Hook our own LoadLibrary functions so we notice when a new library (like the d3d ones) is loaded.
 		hhLoad.setup(reinterpret_cast<voidFunc>(LoadLibraryA), reinterpret_cast<voidFunc>(MyLoadLibrary));
 		hhLoadW.setup(reinterpret_cast<voidFunc>(LoadLibraryW), reinterpret_cast<voidFunc>(MyLoadLibraryW));
-		hhFree.setup(reinterpret_cast<voidFunc>(FreeLibrary), reinterpret_cast<voidFunc>(MyFreeLibrary));
 
 		checkHooks(true);
 		ods("Lib: Injected into %s", procname);
@@ -744,8 +728,6 @@ static void dllmainProcDetach() {
 	hhLoad.reset();
 	hhLoadW.restore(true);
 	hhLoadW.reset();
-	hhFree.restore(true);
-	hhFree.reset();
 
 	if (sd)
 		UnmapViewOfFile(sd);