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 <makita.toshiaki@lab.ntt.co.jp>
Acked-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index 4a37161..5fee2fe 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -241,6 +241,34 @@
return false;
}
+/* Called under RCU */
+bool br_should_learn(struct net_bridge_port *p, struct sk_buff *skb, u16 *vid)
+{
+ struct net_bridge *br = p->br;
+ struct net_port_vlans *v;
+
+ if (!br->vlan_enabled)
+ return true;
+
+ v = rcu_dereference(p->vlan_info);
+ if (!v)
+ return false;
+
+ br_vlan_get_tag(skb, vid);
+ if (!*vid) {
+ *vid = br_get_pvid(v);
+ if (*vid == VLAN_N_VID)
+ return false;
+
+ return true;
+ }
+
+ if (test_bit(*vid, v->vlan_bitmap))
+ return true;
+
+ return false;
+}
+
/* Must be protected by RTNL.
* Must be called with vid in range from 1 to 4094 inclusive.
*/