From 3a45ed9afc5d3f009e8358ae01a8360c70ae6e32 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Paul=20H=C3=BCber?= Date: Sun, 26 Feb 2017 17:58:19 +0100 Subject: [PATCH] l2tp: avoid use-after-free caused by l2tp_ip_backlog_recv MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 51fb60eb162ab84c5edf2ae9c63cf0b878e5547e upstream. l2tp_ip_backlog_recv may not return -1 if the packet gets dropped. The return value is passed up to ip_local_deliver_finish, which treats negative values as an IP protocol number for resubmission. Signed-off-by: Paul Hüber Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/l2tp/l2tp_ip.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index a753c9b2336f..6f12fd694d29 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -432,7 +432,7 @@ static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) drop: IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS); kfree_skb(skb); - return -1; + return 0; } /* Userspace will call sendmsg() on the tunnel socket to send L2TP -- 2.39.5