From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45664 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933654AbdJJT5y (ORCPT ); Tue, 10 Oct 2017 15:57:54 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Willem de Bruijn , Eric Dumazet , "David S. Miller" Subject: [PATCH 4.9 070/105] packet: only test po->has_vnet_hdr once in packet_snd Date: Tue, 10 Oct 2017 21:50:41 +0200 Message-Id: <20171010192544.727079507@linuxfoundation.org> In-Reply-To: <20171010192533.717049376@linuxfoundation.org> References: <20171010192533.717049376@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Willem de Bruijn [ Upstream commit da7c9561015e93d10fe6aab73e9288e0d09d65a6 ] Packet socket option po->has_vnet_hdr can be updated concurrently with other operations if no ring is attached. Do not test the option twice in packet_snd, as the value may change in between calls. A race on setsockopt disable may cause a packet > mtu to be sent without having GSO options set. Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.") Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1713,7 +1713,7 @@ static int fanout_add(struct sock *sk, u } spin_unlock(&po->bind_lock); - if (err && !refcount_read(&match->sk_ref)) { + if (err && !atomic_read(&match->sk_ref)) { list_del(&match->list); kfree(match); } @@ -2838,6 +2838,7 @@ static int packet_snd(struct socket *soc struct virtio_net_hdr vnet_hdr = { 0 }; int offset = 0; struct packet_sock *po = pkt_sk(sk); + bool has_vnet_hdr = false; int hlen, tlen, linear; int extra_len = 0; @@ -2881,6 +2882,7 @@ static int packet_snd(struct socket *soc err = packet_snd_vnet_parse(msg, &len, &vnet_hdr); if (err) goto out_unlock; + has_vnet_hdr = true; } if (unlikely(sock_flag(sk, SOCK_NOFCS))) { @@ -2941,7 +2943,7 @@ static int packet_snd(struct socket *soc packet_pick_tx_queue(dev, skb); - if (po->has_vnet_hdr) { + if (has_vnet_hdr) { err = packet_snd_vnet_gso(skb, &vnet_hdr); if (err) goto out_free;