[PPPOL2TP]: Fix use-after-free Don't use skb->len after passing it to ip_queue_xmit. Signed-off-by: Patrick McHardy --- commit 86394ab99d7a4532cf23f8d456aecfa6e3085dfd tree 704cfbb8d9c06f79c21a54f189608db1d1b06915 parent 2e27afb300b56d83bb03fbfa68852b9c1e2920c6 author Patrick McHardy Tue, 17 Jul 2007 14:11:37 +0200 committer Patrick McHardy Tue, 17 Jul 2007 14:11:37 +0200 drivers/net/pppol2tp.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c index 5891a0f..856610f 100644 --- a/drivers/net/pppol2tp.c +++ b/drivers/net/pppol2tp.c @@ -824,6 +824,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh struct pppol2tp_session *session; struct pppol2tp_tunnel *tunnel; struct udphdr *uh; + unsigned int len; error = -ENOTCONN; if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) @@ -912,14 +913,15 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh } /* Queue the packet to IP for output */ + len = skb->len; error = ip_queue_xmit(skb, 1); /* Update stats */ if (error >= 0) { tunnel->stats.tx_packets++; - tunnel->stats.tx_bytes += skb->len; + tunnel->stats.tx_bytes += len; session->stats.tx_packets++; - session->stats.tx_bytes += skb->len; + session->stats.tx_bytes += len; } else { tunnel->stats.tx_errors++; session->stats.tx_errors++; @@ -958,6 +960,7 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb) __wsum csum = 0; struct sk_buff *skb2 = NULL; struct udphdr *uh; + unsigned int len; if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) goto abort; @@ -1050,14 +1053,15 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb) skb2->dst = sk_dst_get(sk_tun); /* Queue the packet to IP for output */ + len = skb2->len; rc = ip_queue_xmit(skb2, 1); /* Update stats */ if (rc >= 0) { tunnel->stats.tx_packets++; - tunnel->stats.tx_bytes += skb2->len; + tunnel->stats.tx_bytes += len; session->stats.tx_packets++; - session->stats.tx_bytes += skb2->len; + session->stats.tx_bytes += len; } else { tunnel->stats.tx_errors++; session->stats.tx_errors++;