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

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Message-ID: <20141112022214.GE11597@verge.net.au>
Date:	Wed, 12 Nov 2014 11:22:16 +0900
From:	Simon Horman <horms@...ge.net.au>
To:	Julian Anastasov <ja@....bg>
Cc:	Calvin Owens <calvinowens@...com>,
	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

On Sat, Nov 08, 2014 at 08:16:58AM +0200, Julian Anastasov wrote:
> 
> 	Hello,
> 
> On Fri, 7 Nov 2014, Calvin Owens wrote:
> 
> > On 11/05/2014 01:21 AM, Julian Anastasov wrote:
> > >
> > >  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.
> > 
> > I'm not sure where exactly you mean: ip_vs_tunnel_xmit_v6() calls
> > ip_vs_prepare_tunneled_skb() to do the allocation, so this patch covers that
> > case.
> > 
> > In older versions of the kernel, ip_vs_tunnel_xmit_v6() does it directly,
> > could that be what you're looking at?
> 
> 	Sorry, it seems I was checking old branch.
> 
> 	Simon, please apply.
> 
> Acked-by: Julian Anastasov <ja@....bg>

Thanks, done.

> > > - 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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