From 7d4372b5ae2f891e8bfa96c98d450255f58b4dc1 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Wed, 18 Jul 2007 02:04:09 -0700 Subject: [PATCH] [PPPOL2TP]: Fix use-after-free Don't use skb->len after passing it to ip_queue_xmit. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- drivers/net/pppol2tp.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c index 5891a0fbdc8b..856610f0624e 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++; -- 2.20.1