[net,2/2] openvswitch: Clear the L4 portion of the key for "later" fragments.

Only the first fragment in a datagram contains the L4 headers.  When the
Open vSwitch module parses a packet, it always sets the IP protocol
field in the key, but can only set the L4 fields on the first fragment.
The original behavior would not clear the L4 portion of the key, so
garbage values would be sent in the key for "later" fragments.  This
patch clears the L4 fields in that circumstance to prevent sending those
garbage values as part of the upcall.

Signed-off-by: Justin Pettit <jpettit@ovn.org>
---
 net/openvswitch/flow.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

On Sat, Aug 24, 2019 at 9:58 AM Justin Pettit <jpettit@ovn.org> wrote:
>
> Only the first fragment in a datagram contains the L4 headers.  When the
> Open vSwitch module parses a packet, it always sets the IP protocol
> field in the key, but can only set the L4 fields on the first fragment.
> The original behavior would not clear the L4 portion of the key, so
> garbage values would be sent in the key for "later" fragments.  This
> patch clears the L4 fields in that circumstance to prevent sending those
> garbage values as part of the upcall.
>
> Signed-off-by: Justin Pettit <jpettit@ovn.org>
> ---
>  net/openvswitch/flow.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
> index bc89e16e0505..0fb2cec08523 100644
> --- a/net/openvswitch/flow.c
> +++ b/net/openvswitch/flow.c
> @@ -623,6 +623,7 @@ static int key_extract(struct sk_buff *skb, struct sw_flow_key *key)
>                 offset = nh->frag_off & htons(IP_OFFSET);
>                 if (offset) {
>                         key->ip.frag = OVS_FRAG_TYPE_LATER;
> +                       memset(&key->tp, 0, sizeof(key->tp));
>                         return 0;
>                 }
>                 if (nh->frag_off & htons(IP_MF) ||
> @@ -740,8 +741,10 @@ static int key_extract(struct sk_buff *skb, struct sw_flow_key *key)
>                         return error;
>                 }
>
> -               if (key->ip.frag == OVS_FRAG_TYPE_LATER)
> +               if (key->ip.frag == OVS_FRAG_TYPE_LATER) {
> +                       memset(&key->tp, 0, sizeof(key->tp));
>                         return 0;
> +               }
>                 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
>                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
>

Looks good to me.

Acked-by: Pravin B Shelar <pshelar@ovn.org>

Thanks,
Pravin.