From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Linus=20L=C3=BCssing?= Subject: [PATCH 2/2] bridge: multicast: enable snooping on general queries only Date: Mon, 10 Mar 2014 04:39:46 +0100 Message-ID: <1394422786-1683-2-git-send-email-linus.luessing@web.de> References: <1394422786-1683-1-git-send-email-linus.luessing@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: Florian Westphal , bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, "David S. Miller" , Stephen Hemminger , =?UTF-8?q?Linus=20L=C3=BCssing?= , Jan Stancek To: netdev@vger.kernel.org Return-path: In-Reply-To: <1394422786-1683-1-git-send-email-linus.luessing@web.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: bridge-bounces@lists.linux-foundation.org Errors-To: bridge-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org Without this check someone could easily create a denial of service by injecting multicast-specific queries to enable the bridge snooping part if no real querier issuing periodic general queries is present on the link which would result in the bridge wrongly shutting down ports for multicast traffic as the bridge did not learn about these listeners. With this patch the snooping code is enabled upon receiving valid, general queries only. Signed-off-by: Linus L=C3=BCssing --- net/bridge/br_multicast.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index c77f073..5dd4fec 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1127,9 +1127,10 @@ static void br_multicast_query_received(struct net= _bridge *br, struct net_bridge_port *port, struct bridge_mcast_querier *querier, int saddr, + bool is_general_query, unsigned long max_delay) { - if (saddr) + if (saddr && is_general_query) br_multicast_update_querier_timer(br, querier, max_delay); else if (timer_pending(&querier->timer)) return; @@ -1190,7 +1191,7 @@ static int br_ip4_multicast_query(struct net_bridge= *br, } =20 br_multicast_query_received(br, port, &br->ip4_querier, !!iph->saddr, - max_delay); + !group, max_delay); =20 if (!group) goto out; @@ -1282,7 +1283,8 @@ static int br_ip6_multicast_query(struct net_bridge= *br, } =20 br_multicast_query_received(br, port, &br->ip6_querier, - !ipv6_addr_any(&ip6h->saddr), max_delay); + !ipv6_addr_any(&ip6h->saddr), + is_general_query, max_delay); =20 if (!group) goto out; --=20 1.7.10.4