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

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Date:   Mon, 28 Nov 2016 16:22:30 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Daniele Di Proietto <diproiettod@....org>
Cc:     netdev@...r.kernel.org, Florian Westphal <fw@...len.de>,
        Pravin B Shelar <pshelar@....org>, Joe Stringer <joe@....org>
Subject: Re: [PATCH net] openvswitch: Fix skb leak in IPv6 reassembly.

On Mon, 2016-11-28 at 15:43 -0800, Daniele Di Proietto 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;
> +		}
>  
>  		key->ip.proto = ipv6_hdr(skb)->nexthdr;
>  		ovs_cb.mru = IP6CB(skb)->frag_max_size;

Interesting, have you followed the "GPF in eth_header" thread today ?

In a nutshell, we want a complete patch, not something that would solve
part of the problem.