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

Antonio Quartulli
2014-01-20T15:07:53Z

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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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