netdev - Re: [PATCH net 1/1] net/ipv4: ip_vti clear skb cb before tunneling.

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Date:	Mon, 10 Jun 2013 18:28:22 -0700
From:	Stephen Hemminger <stephen@...workplumber.org>
To:	Saurabh Mohan <saumoh@...il.com>
Cc:	netdev <netdev@...r.kernel.org>, Saurabh Mohan <saurabh@...tta.com>
Subject: Re: [PATCH net 1/1] net/ipv4: ip_vti clear skb cb before tunneling.

On Mon, 10 Jun 2013 17:45:10 -0700
Saurabh Mohan <saumoh@...il.com> wrote:

> From: Saurabh Mohan <saurabh@...tta.com>
> 
> If users apply shaper to vti tunnel then it will cause a kernel crash. The
> problem seems to be due to the vti_tunnel_xmit function not clearing
> skb->opt field before passing the packet to xfrm tunneling code.
> 
> Signed-off-by: Saurabh Mohan <saurabh@...tta.com>
> ---
>  net/ipv4/ip_vti.c |    3 +--
>  1 files changed, 1 insertions(+), 2 deletions(-)
> 
> diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
> index 9d2bdb2..c118f6b 100644
> --- a/net/ipv4/ip_vti.c
> +++ b/net/ipv4/ip_vti.c
> @@ -361,8 +361,7 @@ static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
>  			tunnel->err_count = 0;
>  	}
>  
> -	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
> -			      IPSKB_REROUTED);
> +	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
>  	skb_dst_drop(skb);
>  	skb_dst_set(skb, &rt->dst);
>  	nf_reset(skb);

Thanks, this applies to 3.9 and earlier kernels. When the tunnel code was unified,
this was fixed in ip_tunnel.c

Acked-by: Stephen Hemminger <stephen@...workplumber.org>
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