netpoll: fix incorrect access to skb data in __netpoll_rx

__netpoll_rx() doesnt properly handle skbs with small header pskb_may_pull() or pskb_trim_rcsum() can change skb->data, we must reload it. Signed-off-by: Eric Dumazet <[email protected]> Signed-off-by: David S. Miller <[email protected]>
rtvt123 · Aug 26, 2011 · e9278a4 · e9278a4
1 parent 3d01556
commit e9278a4
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
@@ -558,13 +558,14 @@ int __netpoll_rx(struct sk_buff *skb)
 	if (skb_shared(skb))
 		goto out;
 
-	iph = (struct iphdr *)skb->data;
 	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 		goto out;
+	iph = (struct iphdr *)skb->data;
 	if (iph->ihl < 5 || iph->version != 4)
 		goto out;
 	if (!pskb_may_pull(skb, iph->ihl*4))
 		goto out;
+	iph = (struct iphdr *)skb->data;
 	if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 		goto out;
 
@@ -579,6 +580,7 @@ int __netpoll_rx(struct sk_buff *skb)
 	if (pskb_trim_rcsum(skb, len))
 		goto out;
 
+	iph = (struct iphdr *)skb->data;
 	if (iph->protocol != IPPROTO_UDP)
 		goto out;