Re: [PATCH net-next 1/9] openvswitch: Scrub packet in ovs_vport_receive()

Joe Stringer
2015-07-31T17:51:11Z

On 31 July 2015 at 07:34, Hannes Frederic Sowa <hannes@redhat.com> wrote:
> On Thu, 2015-07-30 at 11:12 -0700, Joe Stringer wrote:
>> Signed-off-by: Joe Stringer <joestringer@nicira.com>
>> ---
>> net/openvswitch/vport.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
>> index d14f594..baa018f 100644
>> --- a/net/openvswitch/vport.c
>> +++ b/net/openvswitch/vport.c
>> @@ -475,6 +475,9 @@ void ovs_vport_receive(struct vport *vport, struct
>> sk_buff *skb,
>> struct sw_flow_key key;
>> int error;
>>
>> + if (!skb->sk || (sock_net(skb->sk) != read_pnet(&vport->dp
>> ->net)))
>> + skb_scrub_packet(skb, true);
>> +
>> stats = this_cpu_ptr(vport->percpu_stats);
>> u64_stats_update_begin(&stats->syncp);
>> stats->rx_packets++;
>
> In general, this shouldn't be necessary as the packet should already be
> scrubbed before they arrive here.
>
> Could you maybe add a WARN_ON and check how those skbs with conntrack
> data traverse the stack? I also didn't understand why make it dependent
> on the socket.

OK, sure. One case I could think of is with an OVS internal port in
another namespace, directly attached to the bridge. I'll have a play
around with WARN_ON and see if I can come up with something more
trimmed down.