From 65c42a2d475d904688436a50aa596f643671461f Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 29 Mar 2018 12:49:52 -0700 Subject: [PATCH] vrf: Fix use after free and double free in vrf_finish_output [ Upstream commit 82dd0d2a9a76fc8fa2b18d80b987d455728bf83a ] Miguel reported an skb use after free / double free in vrf_finish_output when neigh_output returns an error. The vrf driver should return after the call to neigh_output as it takes over the skb on error path as well. Patch is a simplified version of Miguel's patch which was written for 4.9, and updated to top of tree. Fixes: 8f58336d3f78a ("net: Add ethernet header for pass through VRF device") Signed-off-by: Miguel Fadon Perlines Signed-off-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/vrf.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c index 67ecf2425b88..5c6a8ef54aec 100644 --- a/drivers/net/vrf.c +++ b/drivers/net/vrf.c @@ -579,12 +579,13 @@ static int vrf_finish_output(struct net *net, struct sock *sk, struct sk_buff *s if (!IS_ERR(neigh)) { sock_confirm_neigh(skb, neigh); ret = neigh_output(neigh, skb); + rcu_read_unlock_bh(); + return ret; } rcu_read_unlock_bh(); err: - if (unlikely(ret < 0)) - vrf_tx_error(skb->dev, skb); + vrf_tx_error(skb->dev, skb); return ret; }