Add a null check to prevent crashes during the vulnerable time when Filter

is not set.

svn path=/trunk/; revision=11729

reactos/drivers/net/ndis/ndis/miniport.c

@@ -377,6 +377,9 @@ MiniEthReceiveIndication(
  *     PacketSize          = Total size of received packet
  */
 {
+    /* If there is no filter, then we can't do any more */
+    if( !Filter ) return;
+
     MiniIndicateData((PLOGICAL_ADAPTER)Filter->Miniport,
 		     MacReceiveContext,
 		     HeaderBuffer,