From cb1f1bd5552dd1a60a4e4e6310b138c8fc0faac1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Gardou?= <jerome.gardou@reactos.org>
Date: Sun, 4 Sep 2011 15:58:48 +0000
Subject: [PATCH] [WIN32K] - Avoid invalid memory write. See issue #5969 for
 more details.

svn path=/trunk/; revision=53583
---
 reactos/subsystems/win32/win32k/ntuser/misc.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/reactos/subsystems/win32/win32k/ntuser/misc.c b/reactos/subsystems/win32/win32k/ntuser/misc.c
index 036c0ceb0ce..0bb0b30d413 100644
--- a/reactos/subsystems/win32/win32k/ntuser/misc.c
+++ b/reactos/subsystems/win32/win32k/ntuser/misc.c
@@ -497,11 +497,14 @@ GetW32ThreadInfo(VOID)
     pti->pClientInfo = pci;
     _SEH2_TRY
     {
-        ProbeForWrite( Teb,
-                       sizeof(TEB),
-                       sizeof(ULONG));
+        if(Teb)
+        {    
+            ProbeForWrite( Teb,
+                           sizeof(TEB),
+                           sizeof(ULONG));
 
-        Teb->Win32ThreadInfo = (PW32THREAD) pti;
+            Teb->Win32ThreadInfo = (PW32THREAD) pti;
+        }
 
         pci->ppi = ppi;
         pci->fsHooks = pti->fsHooks;