From e0d7968ab6c8bce2437b36fa7f04117e333f196d Mon Sep 17 00:00:00 2001 From: Toshiaki Makita Date: Mon, 26 May 2014 15:15:53 +0900 Subject: bridge: Prevent insertion of FDB entry with disallowed vlan br_handle_local_finish() is allowing us to insert an FDB entry with disallowed vlan. For example, when port 1 and 2 are communicating in vlan 10, and even if vlan 10 is disallowed on port 3, port 3 can interfere with their communication by spoofed src mac address with vlan id 10. Note: Even if it is judged that a frame should not be learned, it should not be dropped because it is destined for not forwarding layer but higher layer. See IEEE 802.1Q-2011 8.13.10. Signed-off-by: Toshiaki Makita Acked-by: Vlad Yasevich Signed-off-by: David S. Miller --- net/bridge/br_input.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/bridge/br_input.c') diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c index 7985deaff52f..04d6348fd530 100644 --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -147,8 +147,8 @@ static int br_handle_local_finish(struct sk_buff *skb) struct net_bridge_port *p = br_port_get_rcu(skb->dev); u16 vid = 0; - br_vlan_get_tag(skb, &vid); - if (p->flags & BR_LEARNING) + /* check if vlan is allowed, to avoid spoofing */ + if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid)) br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false); return 0; /* process further */ } -- cgit 1.4.1