From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754152AbdJSNw1 (ORCPT ); Thu, 19 Oct 2017 09:52:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:47780 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754132AbdJSNwY (ORCPT ); Thu, 19 Oct 2017 09:52:24 -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 4.4 17/46] packet: only test po->has_vnet_hdr once in packet_snd Date: Thu, 19 Oct 2017 15:48:53 +0200 Message-Id: <20171019134846.521254412@linuxfoundation.org> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171019134845.293630834@linuxfoundation.org> References: <20171019134845.293630834@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-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 @@ -1717,7 +1717,7 @@ 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); } @@ -2656,6 +2656,7 @@ static int packet_snd(struct socket *soc int vnet_hdr_len; struct packet_sock *po = pkt_sk(sk); unsigned short gso_type = 0; + bool has_vnet_hdr = false; int hlen, tlen, linear; int extra_len = 0; ssize_t n; @@ -2743,6 +2744,7 @@ static int packet_snd(struct socket *soc goto out_unlock; } + has_vnet_hdr = true; } if (unlikely(sock_flag(sk, SOCK_NOFCS))) { @@ -2802,7 +2804,7 @@ static int packet_snd(struct socket *soc packet_pick_tx_queue(dev, skb); - if (po->has_vnet_hdr) { + if (has_vnet_hdr) { if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { u16 s = __virtio16_to_cpu(vio_le(), vnet_hdr.csum_start); u16 o = __virtio16_to_cpu(vio_le(), vnet_hdr.csum_offset);