From 08810169e7fac2beba5869ef2d5e897bc643aed0 Mon Sep 17 00:00:00 2001
From: Timo Kreuzer <timo.kreuzer@reactos.org>
Date: Wed, 27 Oct 2010 12:51:32 +0000
Subject: [PATCH] [WIN32K] Fix possible NULL pointer dereference. Spotted by
 Amine Khaldi.

svn path=/trunk/; revision=49303
---
 reactos/subsystems/win32/win32k/ntuser/event.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/reactos/subsystems/win32/win32k/ntuser/event.c b/reactos/subsystems/win32/win32k/ntuser/event.c
index 2c5a91e53c1..e768c2e09d0 100644
--- a/reactos/subsystems/win32/win32k/ntuser/event.c
+++ b/reactos/subsystems/win32/win32k/ntuser/event.c
@@ -299,17 +299,21 @@ NtUserNotifyWinEvent(
    UserEnterExclusive();
 
    /* Validate input */
-   if (hWnd && (hWnd != INVALID_HANDLE_VALUE) && !(Window = UserGetWindowObject(hWnd)))
+   if (hWnd && (hWnd != INVALID_HANDLE_VALUE))
    {
-      UserLeave();
-      return;
+     Window = UserGetWindowObject(hWnd);
+     if (!Window)
+     {
+       UserLeave();
+       return;
+     }
    }
 
    if (gpsi->dwInstalledEventHooks & GetMaskFromEvent(Event))
    {
-      UserRefObjectCo(Window, &Ref);
+      if (Window) UserRefObjectCo(Window, &Ref);
       IntNotifyWinEvent( Event, Window, idObject, idChild, WEF_SETBYWNDPTI);
-      UserDerefObjectCo(Window);
+      if (Window) UserDerefObjectCo(Window);
    }
    UserLeave();
 }
-- 
2.17.1