path: root/net/bridge
diff options
authorVlad Yasevich <vyasevic@redhat.com>2014-03-27 21:51:18 -0400
committerDavid S. Miller <davem@davemloft.net>2014-03-28 17:14:02 -0400
commitfc92f745f8d0d3736ce5afb00a905d7cc61f9c46 (patch)
tree606412dc5f865c5e2b11b6def1b75eca213aca30 /net/bridge
parent53d6471cef17262d3ad1c7ce8982a234244f68ec (diff)
bridge: Fix crash with vlan filtering and tcpdump
When the vlan filtering is enabled on the bridge, but the filter is not configured on the bridge device itself, running tcpdump on the bridge device will result in a an Oops with NULL pointer dereference. The reason is that br_pass_frame_up() will bypass the vlan check because promisc flag is set. It will then try to get the table pointer and process the packet based on the table. Since the table pointer is NULL, we oops. Catch this special condition in br_handle_vlan(). Reported-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> CC: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> Signed-off-by: Vlad Yasevich <vyasevic@redhat.com> Acked-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge')
2 files changed, 20 insertions, 5 deletions
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 28d544627422..d0cca3c65f01 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -29,6 +29,7 @@ static int br_pass_frame_up(struct sk_buff *skb)
struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
struct net_bridge *br = netdev_priv(brdev);
struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
+ struct net_port_vlans *pv;
@@ -39,18 +40,18 @@ static int br_pass_frame_up(struct sk_buff *skb)
* packet is allowed except in promisc modue when someone
* may be running packet capture.
+ pv = br_get_vlan_info(br);
if (!(brdev->flags & IFF_PROMISC) &&
- !br_allowed_egress(br, br_get_vlan_info(br), skb)) {
+ !br_allowed_egress(br, pv, skb)) {
return NET_RX_DROP;
- skb = br_handle_vlan(br, br_get_vlan_info(br), skb);
- if (!skb)
- return NET_RX_DROP;
indev = skb->dev;
skb->dev = brdev;
+ skb = br_handle_vlan(br, pv, skb);
+ if (!skb)
+ return NET_RX_DROP;
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index c77eed56b045..f23c74b3a953 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -128,6 +128,20 @@ struct sk_buff *br_handle_vlan(struct net_bridge *br,
if (!br->vlan_enabled)
goto out;
+ /* Vlan filter table must be configured at this point. The
+ * only exception is the bridge is set in promisc mode and the
+ * packet is destined for the bridge device. In this case
+ * pass the packet as is.
+ */
+ if (!pv) {
+ if ((br->dev->flags & IFF_PROMISC) && skb->dev == br->dev) {
+ goto out;
+ } else {
+ kfree_skb(skb);
+ return NULL;
+ }
+ }
/* At this point, we know that the frame was filtered and contains
* a valid vlan id. If the vlan id is set in the untagged bitmap,
* send untagged; otherwise, send tagged.