[COMCTL32] Check for NULL pointer when handling BCM_GETIDEALSIZE.

Fixes crash in comctl32_winetest:button.

diff --git a/dll/win32/comctl32/button.c b/dll/win32/comctl32/button.c
index 5906747..1d7431d 100644 (file)
--- a/dll/win32/comctl32/button.c
+++ b/dll/win32/comctl32/button.c
@@ -941,6 +941,11 @@ static LRESULT CALLBACK BUTTON_WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, L
         BOOL ret = FALSE;
         SIZE* pSize = (SIZE*)lParam;
 
+        if (!pSize)
+        {
+            return FALSE;
+        }
+
         if (btn_type == BS_PUSHBUTTON || 
             btn_type == BS_DEFPUSHBUTTON ||
             btn_type == BS_USERBUTTON)