Add pointer check for NULL before dereference it.

Signed-off-by: sfu5
Reviewed-by: xdu2
Reviewed-by: ydong10


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12514 6f19259b-4bc3-4df7-8a09-765794883524

NetworkPkg/IpSecDxe/IpSecImpl.c

@@ -1237,6 +1237,7 @@ IpSecTunnelOutboundPacket (
       );
   } else {
     InnerHead = AllocateZeroPool (sizeof (EFI_IP6_HEADER) + *OptionsLength);
+    ASSERT (InnerHead != NULL);
     CopyMem (
       InnerHead,
       IpHead,