netdev - Re: [PATCH net] openvswitch: Fix skb leak in IPv6 reassembly.

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Date:   Mon, 28 Nov 2016 23:39:56 -0800
From:   Pravin Shelar <pshelar@....org>
To:     Daniele Di Proietto <diproiettod@....org>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Florian Westphal <fw@...len.de>, Joe Stringer <joe@....org>
Subject: Re: [PATCH net] openvswitch: Fix skb leak in IPv6 reassembly.

On Mon, Nov 28, 2016 at 3:43 PM, Daniele Di Proietto
<diproiettod@....org> wrote:
> If nf_ct_frag6_gather() returns an error other than -EINPROGRESS, it
> means that we still have a reference to the skb.  We should free it
> before returning from handle_fragments, as stated in the comment above.
>
> Fixes: daaa7d647f81 ("netfilter: ipv6: avoid nf_iterate recursion")
> CC: Florian Westphal <fw@...len.de>
> CC: Pravin B Shelar <pshelar@....org>
> CC: Joe Stringer <joe@....org>
> Signed-off-by: Daniele Di Proietto <diproiettod@....org>
> ---
>  net/openvswitch/conntrack.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
> index 31045ef..fecefa2 100644
> --- a/net/openvswitch/conntrack.c
> +++ b/net/openvswitch/conntrack.c
> @@ -370,8 +370,11 @@ static int handle_fragments(struct net *net, struct sw_flow_key *key,
>                 skb_orphan(skb);
>                 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
>                 err = nf_ct_frag6_gather(net, skb, user);
> -               if (err)
> +               if (err) {
> +                       if (err != -EINPROGRESS)
> +                               kfree_skb(skb);
>                         return err;
> +               }
>

This fixes the code. But the patch is adding yet another skb-kfree in
conntrack code. we could simplify it by reusing error handling in
do_execute_actions().
If you think that is too complicated for stable branch, I am fine with
this patch going in as it is.