[greatlrd] 20421: some case from win32k can call to RtlClearAllBits with NULL pointer. and check for null pointer after RtlClearAllBits. This take care of those case for moment.

some case from win32k can call to RtlClearAllBits with NULL pointer. and
check for null pointer after RtlClearAllBits. This take care of those
case for moment.
Modified: trunk/reactos/lib/rtl/bitmap.c
  _____
Modified: trunk/reactos/lib/rtl/bitmap.c
--- trunk/reactos/lib/rtl/bitmap.c      2005-12-29 13:13:14 UTC (rev
20420)
+++ trunk/reactos/lib/rtl/bitmap.c      2005-12-29 13:43:25 UTC (rev
20421)
@@ -125,9 +125,15 @@
 VOID NTAPI
 RtlClearAllBits(IN OUT PRTL_BITMAP BitMapHeader)
 {
-    memset(BitMapHeader->Buffer,
-          0x00,
-          ROUND_UP(BitMapHeader->SizeOfBitMap, 8) / 8);
+   if (BitMapHeader != NULL)
+   {
+     if (BitMapHeader->Buffer != NULL)
+     {
+        memset(BitMapHeader->Buffer,
+                  0x00,
+                  ROUND_UP(BitMapHeader->SizeOfBitMap, 8) / 8);
+     }
+   }
 }