vxlan: drop packets from invalid src-address

The VXLAN driver currently does not check if the inner layer2
source-address is valid.

In case source-address snooping/learning is enabled, a entry in the FDB
for the invalid address is created with the layer3 address of the tunnel
endpoint.

If the frame happens to have a non-unicast address set, all this
non-unicast traffic is subsequently not flooded to the tunnel network
but sent to the learnt host in the FDB. To make matters worse, this FDB
entry does not expire.

Apply the same filtering for packets as it is done for bridges. This not
only drops these invalid packets but avoids them from being learnt into
the FDB.

Fixes: d342894c5d2f ("vxlan: virtual extensible lan")
Suggested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David Bauer <mail@david-bauer.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 3495591a5c29b2aa929fcf307c2970c661ec2ea6..ba319fc219571975597bf7aad3d913e77dac6898 100644 (file)
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -1615,6 +1615,10 @@ static bool vxlan_set_mac(struct vxlan_dev *vxlan,
        if (ether_addr_equal(eth_hdr(skb)->h_source, vxlan->dev->dev_addr))
                return false;
 
+       /* Ignore packets from invalid src-address */
+       if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
+               return false;
+
        /* Get address from the outer IP header */
        if (vxlan_get_sk_family(vs) == AF_INET) {
                saddr.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;