Re: [B.A.T.M.A.N.] [PATCH-maint 4/4] batman-adv: detect local excess vlans in TT request

[Antonio Quartulli <antonio@meshcoding.com>]

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On 21/08/15 17:15, Simon Wunderlich wrote:
> If the local representation of the global TT table of one originator has
> more VLAN entries than the respective TT update, there is some
> inconsistency present. By detecting and reporting this inconsistency,
> the global table gets updated and the excess VLAN will get removed in
> the process.
> 
> Reported-by: Alessandro Bolletta <alessandro@mediaspot.net>
> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
> ---
>  net/batman-adv/translation-table.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
> index dced2da..1adb72e 100644
> --- a/net/batman-adv/translation-table.c
> +++ b/net/batman-adv/translation-table.c
> @@ -2392,6 +2392,7 @@ static bool batadv_tt_global_check_crc(struct batadv_orig_node *orig_node,
>  	struct batadv_tvlv_tt_vlan_data *tt_vlan_tmp;
>  	struct batadv_orig_node_vlan *vlan;
>  	uint32_t crc;
> +	bool found;
>  	int i;
>  
>  	/* check if each received CRC matches the locally stored one */
> @@ -2418,6 +2419,26 @@ static bool batadv_tt_global_check_crc(struct batadv_orig_node *orig_node,
>  			return false;
>  	}
>  
> +	/* check if any excess VLANs exist locally for the originator
> +	 * which are not mentioned in the TVLV from the originator.
> +	 */
> +	rcu_read_lock();
> +	list_for_each_entry_rcu(vlan, &orig_node->vlan_list, list) {
> +		found = false;
> +
> +		for (i = 0; i < num_vlan; i++) {
> +			tt_vlan_tmp = tt_vlan + i;
> +			if (ntohs(tt_vlan_tmp->vid) == vlan->vid) {
> +				found = true;
> +				break;
> +			}
> +		}
> +
> +		if (!found)
> +			return false;
> +	}
> +	rcu_read_unlock();
> +

NAK.

we already do this check slightly above in this function with the
following code:

2426                 vlan = batadv_orig_node_vlan_get(orig_node,
2427
ntohs(tt_vlan_tmp->vid));
2428                 if (!vlan)
2429                         return false;

batadv_orig_node_vlan_get() returns NULL if we don't know this VLAN for
that Originator, therefore the CRC check fails here.


Cheers,

>  	return true;
>  }
>  
> 

-- 
Antonio Quartulli


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