linux-kernel - Re: [PATCH] ipvs: Keep skb->sk when allocating headroom on tunnel xmit

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Date:	Wed, 5 Nov 2014 11:21:13 +0200 (EET)
From:	Julian Anastasov <ja@....bg>
To:	Calvin Owens <calvinowens@...com>
cc:	Simon Horman <horms@...ge.net.au>,
	Wensong Zhang <wensong@...ux-vs.org>,
	lvs-devel@...r.kernel.org, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org, agartrell@...com, kernel-team@...com
Subject: Re: [PATCH] ipvs: Keep skb->sk when allocating headroom on tunnel
 xmit


	Hello,

On Tue, 4 Nov 2014, Calvin Owens wrote:

> ip_vs_prepare_tunneled_skb() ignores ->sk when allocating a new
> skb, either unconditionally setting ->sk to NULL or allowing
> the uninitialized ->sk from a newly allocated skb to leak through
> to the caller.
> 
> This patch properly copies ->sk and increments its reference count.
> 
> Signed-off-by: Calvin Owens <calvinowens@...com>

	Good catch. Please, extend your patch to
fix also the second place that has such error,
ip_vs_tunnel_xmit_v6. This call is missing from long time,
it was not needed. But commits that allow skb->sk (local
clients) already need it, eg.

- f2428ed5e7bc89c7 ("ipvs: load balance ipv6 connections from a local
process"), 2.6.28
- 4856c84c1358b798 ("ipvs: load balance IPv4 connections from a local 
process"), 2.6.28

> ---
>  net/netfilter/ipvs/ip_vs_xmit.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
> index 437a366..bd90bf8 100644
> --- a/net/netfilter/ipvs/ip_vs_xmit.c
> +++ b/net/netfilter/ipvs/ip_vs_xmit.c
> @@ -846,6 +846,8 @@ ip_vs_prepare_tunneled_skb(struct sk_buff *skb, int skb_af,
>  		new_skb = skb_realloc_headroom(skb, max_headroom);
>  		if (!new_skb)
>  			goto error;
> +		if (skb->sk)
> +			skb_set_owner_w(new_skb, skb->sk);
>  		consume_skb(skb);
>  		skb = new_skb;
>  	}

Regards

--
Julian Anastasov <ja@....bg>
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