Re: [PATCH] ip_forward: Drop frames with attached skb->sk

[yzhu1 <Yanjun.Zhu@windriver.com>]

On 04/14/2015 01:52 PM, Sebastian Poehn wrote:
> Initial discussion was:
> [FYI] xfrm: Don't lookup sk_policy for timewait sockets
>
> Forwarded frames should not have a socket attached. Especially
> tw sockets will lead to panics later-on in the stack.
>
> This was observed with TPROXY assigning a tw socket and broken
> policy routing (misconfigured). As a result frame enters
> forwarding path instead of input. We cannot solve this in
> TPROXY as it cannot know that policy routing is broken.
>
> Signed-off-by: Sebastian Poehn <sebastian.poehn@gmail.com>
> ---
> diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c
> index 939992c..2fc3b3e 100644
> --- a/net/ipv4/ip_forward.c
> +++ b/net/ipv4/ip_forward.c
> @@ -82,6 +82,10 @@ int ip_forward(struct sk_buff *skb)
>   	if (skb->pkt_type != PACKET_HOST)
>   		goto drop;
>   
> +	/* this should happen neither */
Sorry. "neither" should be "either"?

Zhu Yanjun
> +	if (unlikely(skb->sk))
> +		goto drop;
> +
>   	if (skb_warn_if_lro(skb))
>   		goto drop;
> --
>
>
> --
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