From: Paul Hüber Date: Sun, 26 Feb 2017 16:58:19 +0000 (+0100) Subject: l2tp: avoid use-after-free caused by l2tp_ip_backlog_recv X-Git-Tag: v5.15~11780^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=51fb60eb162ab84c5edf2ae9c63cf0b878e5547e;p=platform%2Fkernel%2Flinux-starfive.git l2tp: avoid use-after-free caused by l2tp_ip_backlog_recv 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 --- diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index c59712057dc8..d25038cfd64e 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -388,7 +388,7 @@ static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) drop: IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); kfree_skb(skb); - return -1; + return 0; } /* Userspace will call sendmsg() on the tunnel socket to send L2TP