Re: [B.A.T.M.A.N.] [PATCHv4 maint] batman-adv: fix potential kernel paging error for unicast transmissions

[Antonio Quartulli <antonio@meshcoding.com>]

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On 20/01/14 11:06, Linus Lüssing wrote:
> batadv_send_skb_prepare_unicast(_4addr) might reallocate the skb's
> data. If it does then our ethhdr pointer is not valid anymore in
> batadv_send_skb_unicast(), resulting in a kernel paging error.
> 
> Fixing this by refetching the ethhdr pointer after the potential
> reallocation.
> 
> Introduced by b46c60b9e1ee7a1909c542413a85875a750955d6
> ("batman-adv: improve unicast packet (re)routing")
> 
> Signed-off-by: Linus Lüssing <linus.luessing@web.de>

Acked-by: Antonio Quartulli <antonio@meshcoding.com>

> ---
> Changes v4:
> * "s/Introduced-by:/Introduced by/" to make checkpatch happy
> 
>  send.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/send.c b/send.c
> index b0a3d76..50df184 100644
> --- a/send.c
> +++ b/send.c
> @@ -281,6 +281,10 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
>  		goto out;
>  	}
>  
> +	/* skb->data might have been reallocated by
> +	 * batadv_send_skb_prepare_unicast*
> +	 */
> +	ethhdr = eth_hdr(skb);
>  	unicast_packet = (struct batadv_unicast_packet *)skb->data;
>  
>  	/* inform the destination node that we are still missing a correct route
> 


-- 
Antonio Quartulli


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