From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:33290 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755811AbeDKSwM (ORCPT ); Wed, 11 Apr 2018 14:52:12 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Miguel Fadon Perlines , David Ahern , "David S. Miller" Subject: [PATCH 4.4 190/190] vrf: Fix use after free and double free in vrf_finish_output Date: Wed, 11 Apr 2018 20:37:16 +0200 Message-Id: <20180411183604.662211905@linuxfoundation.org> In-Reply-To: <20180411183550.114495991@linuxfoundation.org> References: <20180411183550.114495991@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Ahern commit 82dd0d2a9a76fc8fa2b18d80b987d455728bf83a upstream. 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 [ backport to 4.4 and 4.9 dropped the sock_confirm_neigh and changed neigh_output to dst_neigh_output ] Signed-off-by: Greg Kroah-Hartman --- drivers/net/vrf.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/drivers/net/vrf.c +++ b/drivers/net/vrf.c @@ -550,13 +550,15 @@ static int vrf_finish_output(struct net neigh = __ipv4_neigh_lookup_noref(dev, nexthop); if (unlikely(!neigh)) neigh = __neigh_create(&arp_tbl, &nexthop, dev, false); - if (!IS_ERR(neigh)) + if (!IS_ERR(neigh)) { ret = dst_neigh_output(dst, 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; }