netdev - bridge: Only flood unregistered groups to routers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 23 Jun 2011 20:39:12 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: bridge: Only flood unregistered groups to routers

Hi:

bridge: Only flood traffic for unregistered groups to routers

The bridge currently floods packets to groups that we have never
seen before to all ports.  This is not required by RFC4541 and
in fact it is not desirable in environment where traffic to
unregistered group is always present.

This patch changes the behaviour so that we only send traffic
to unregistered groups to ports marked as routers.

The user can always force flooding behaviour to any given port
by marking it as a router.

Note that this change does not apply to traffic to 224.0.0.X
as traffic to those groups must always be flooded to all ports.

Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 29b9812..2d85ca7 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1379,8 +1379,11 @@ static int br_multicast_ipv4_rcv(struct net_bridge *br,
 	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
 		return -EINVAL;

-	if (iph->protocol != IPPROTO_IGMP)
+	if (iph->protocol != IPPROTO_IGMP) {
+		if ((iph->daddr & IGMP_LOCAL_GROUP_MASK) != IGMP_LOCAL_GROUP)
+			BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
 		return 0;
+	}

 	len = ntohs(iph->tot_len);
 	if (skb->len < len || len < ip_hdrlen(skb))

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html