From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932423AbdL1R55 (ORCPT ); Thu, 28 Dec 2017 12:57:57 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:59072 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753757AbdL1RNv (ORCPT ); Thu, 28 Dec 2017 12:13:51 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Paolo Abeni" , "David S. Miller" , "Hannes Frederic Sowa" Date: Thu, 28 Dec 2017 17:05:44 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 075/204] ipv4: fix broadcast packets reception In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.52-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni commit ad0ea1989cc4d5905941d0a9e62c63ad6d859cef upstream. Currently, ingress ipv4 broadcast datagrams are dropped since, in udp_v4_early_demux(), ip_check_mc_rcu() is invoked even on bcast packets. This patch addresses the issue, invoking ip_check_mc_rcu() only for mcast packets. Fixes: 6e5403093261 ("ipv4/udp: Verify multicast group is ours in upd_v4_early_demux()") Signed-off-by: Paolo Abeni Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/ipv4/udp.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1974,10 +1974,14 @@ void udp_v4_early_demux(struct sk_buff * if (!in_dev) return; - ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr, - iph->protocol); - if (!ours) - return; + /* we are supposed to accept bcast packets */ + if (skb->pkt_type == PACKET_MULTICAST) { + ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr, + iph->protocol); + if (!ours) + return; + } + sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr, uh->source, iph->saddr, dif); } else if (skb->pkt_type == PACKET_HOST) {