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bridge: vlan: fix possible null vlgrp deref while registering new port

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While a new port is being initialized the rx_handler gets set, but the
vlans get initialized later in br_add_if() and in that window if we
receive a frame with a link-local address we can try to dereference
p->vlgrp in:
br_handle_frame() -> br_handle_local_finish() -> br_should_learn()

Fix this by checking vlgrp before using it.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nikolay Aleksandrov 2015-09-30 20:16:52 +02:00 committed by David S. Miller
parent 8af78b6487
commit 468e794458
1 changed files with 3 additions and 1 deletions
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4
net/bridge/br_vlan.c
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@ -476,13 +476,15 @@ bool br_allowed_egress(struct net_bridge_vlan_group *vg,
/* Called under RCU */
bool br_should_learn(struct net_bridge_port *p, struct sk_buff *skb, u16 *vid)
{
struct net_bridge_vlan_group *vg;
struct net_bridge *br = p->br;
/* If filtering was disabled at input, let it pass. */
if (!br->vlan_enabled)
return true;
if (!p->vlgrp->num_vlans)
vg = p->vlgrp;
if (!vg || !vg->num_vlans)
return false;
if (!br_vlan_get_tag(skb, vid) && skb->vlan_proto != br->vlan_proto)