[IPX]: Header length validation needed

This patch will linearize and check there is enough data.
It handles the pprop case as well as avoiding a whole audit of
the routing code.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipx/af_ipx.c b/net/ipx/af_ipx.c
index aa34ff4..c13e86b 100644
--- a/net/ipx/af_ipx.c
+++ b/net/ipx/af_ipx.c
@@ -1646,7 +1646,8 @@
 	ipx_pktsize	= ntohs(ipx->ipx_pktsize);
 	
 	/* Too small or invalid header? */
-	if (ipx_pktsize < sizeof(struct ipxhdr) || ipx_pktsize > skb->len)
+	if (ipx_pktsize < sizeof(struct ipxhdr) ||
+	    !pskb_may_pull(skb, ipx_pktsize))
 		goto drop;
                         
 	if (ipx->ipx_checksum != IPX_NO_CHECKSUM &&