diff options
| author | Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> | 2014-05-26 15:15:53 +0900 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-06-02 13:38:23 -0700 |
| commit | e0d7968ab6c8bce2437b36fa7f04117e333f196d (patch) | |
| tree | 8b066b3ba7134569ba12b5dd21b31be2621adf3c /net | |
| parent | bfc5184b69cf9eeb286137640351c650c27f118a (diff) | |
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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/bridge/br_input.c | 4 | ||||
| -rw-r--r-- | net/bridge/br_private.h | 7 | ||||
| -rw-r--r-- | net/bridge/br_vlan.c | 28 |
3 files changed, 37 insertions, 2 deletions
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 */ } diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 06811d79f89f..59d3a85c5873 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -581,6 +581,7 @@ bool br_allowed_ingress(struct net_bridge *br, struct net_port_vlans *v, struct sk_buff *skb, u16 *vid); bool br_allowed_egress(struct net_bridge *br, const struct net_port_vlans *v, const struct sk_buff *skb); +bool br_should_learn(struct net_bridge_port *p, struct sk_buff *skb, u16 *vid); struct sk_buff *br_handle_vlan(struct net_bridge *br, const struct net_port_vlans *v, struct sk_buff *skb); @@ -648,6 +649,12 @@ static inline bool br_allowed_egress(struct net_bridge *br, return true; } +static inline bool br_should_learn(struct net_bridge_port *p, + struct sk_buff *skb, u16 *vid) +{ + return true; +} + static inline struct sk_buff *br_handle_vlan(struct net_bridge *br, const struct net_port_vlans *v, struct sk_buff *skb) diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c index 4a3716102789..5fee2feaf292 100644 --- a/net/bridge/br_vlan.c +++ b/net/bridge/br_vlan.c @@ -241,6 +241,34 @@ bool br_allowed_egress(struct net_bridge *br, 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. */ |