1. When get value from AltCfg data, check the varstore type first.

2. Check the pointer's validation before using it.

Signed-off-by:ydong10
Reviewed-by:lgao4


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11816 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/SetupBrowserDxe/Presentation.c

@@ -1023,7 +1023,9 @@ FindNextMenu (
   }
 
   Selection->Statement = NULL;
-  CurrentMenu->QuestionId = 0;  
+  if (CurrentMenu != NULL) {
+    CurrentMenu->QuestionId = 0;
+  }
 
   Selection->Action = UI_ACTION_EXIT;
   return TRUE;