tipc: Fix skb_under_panic when configuring TIPC without privileges

This patch prevents a TIPC configuration command requiring network
administrator privileges from triggering an skbuff underrun if it
is issued by a process lacking those privileges.  The revised error
handling code avoids the use of a potentially uninitialized global
variable by transforming the unauthorized command into a new command,
then following the standard command processing path to generate the
required error message.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/tipc_config.h b/include/linux/tipc_config.h
index b0c916d..2bc6fa4 100644
--- a/include/linux/tipc_config.h
+++ b/include/linux/tipc_config.h
@@ -2,7 +2,7 @@
  * include/linux/tipc_config.h: Include file for TIPC configuration interface
  * 
  * Copyright (c) 2003-2006, Ericsson AB
- * Copyright (c) 2005, Wind River Systems
+ * Copyright (c) 2005-2007, Wind River Systems
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -136,6 +136,14 @@
 #define  TIPC_CMD_SET_NETID         0x800B    /* tx unsigned, rx none */
 
 /*
+ * Reserved commands:
+ * May not be issued by any process.
+ * Used internally by TIPC.
+ */
+
+#define  TIPC_CMD_NOT_NET_ADMIN     0xC001    /* tx none, rx none */
+
+/*
  * TLV types defined for TIPC
  */