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 <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index adf84dd..5262251 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -558,13 +558,14 @@
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 @@
if (pskb_trim_rcsum(skb, len))
goto out;
+ iph = (struct iphdr *)skb->data;
if (iph->protocol != IPPROTO_UDP)
goto out;