l2tp: fix l2tp_udp_recv_core()

pskb_may_pull() can change skb->data, so we have to load ptr/optr at the
right place.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 4 deletions

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index bf8d50c67931..cf0f308abf5e 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -756,9 +756,6 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
                 goto error;
         }
 
-        /* Point to L2TP header */
-        optr = ptr = skb->data;
-
         /* Trace packet contents, if enabled */
         if (tunnel->debug & L2TP_MSG_DATA) {
                 length = min(32u, skb->len);
@@ -769,12 +766,15 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
 
                 offset = 0;
                 do {
-                        printk(" %02X", ptr[offset]);
+                        printk(" %02X", skb->data[offset]);
                 } while (++offset < length);
 
                 printk("\n");
         }
 
+        /* Point to L2TP header */
+        optr = ptr = skb->data;
+
         /* Get L2TP header flags */
         hdrflags = ntohs(*(__be16 *) ptr);