netdev - Re: [PATCH net 2/2] openvswitch: Clear the L4 portion of the key for "later" fragments.

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Date:   Sun, 25 Aug 2019 10:00:27 -0700
From:   Pravin Shelar <pshelar@....org>
To:     Justin Pettit <jpettit@....org>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Joe Stringer <joe@...d.net.nz>
Subject: Re: [PATCH net 2/2] openvswitch: Clear the L4 portion of the key for
 "later" fragments.

On Sat, Aug 24, 2019 at 9:58 AM Justin Pettit <jpettit@....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@....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@....org>

Thanks,
Pravin.