netdev - Re: [PATCH 1/2] bridge: Check if vlan filtering is enabled only once.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <54170011.6020005@redhat.com>
Date:	Mon, 15 Sep 2014 11:04:49 -0400
From:	Vlad Yasevich <vyasevic@...hat.com>
To:	Toshiaki Makita <toshiaki.makita1@...il.com>,
	Vladislav Yasevich <vyasevich@...il.com>,
	netdev@...r.kernel.org
CC:	shemminger@...tta.com,
	Toshiaki Makita <makita.toshiaki@....ntt.co.jp>
Subject: Re: [PATCH 1/2] bridge: Check if vlan filtering is enabled only once.

On 09/14/2014 10:43 AM, Toshiaki Makita wrote:
> (14/09/13 (土) 5:26), Vladislav Yasevich wrote:
>> The bridge code checks if vlan filtering is enabled on both
>> ingress and egress.   When the state flip happens, it
>> is possible for the bridge to currently be forwarding packets
>> and forwarding behavior becomes non-deterministic.  Bridge
>> may drop packets on some interfaces, but not others.
>>
>> This patch solves this by caching the filtered state of the
>> packet into skb_cb on ingress.  The skb_cb is guaranteed to
>> not be over-written between the time packet entres bridge
>> forwarding path and the time it leaves it.  On egress, we
>> can then check the cached state to see if we need to
>> apply filtering information.
> ...
>> @@ -270,7 +275,8 @@ bool br_should_learn(struct net_bridge_port *p, struct sk_buff *skb, u16 *vid)
>>   	struct net_bridge *br = p->br;
>>   	struct net_port_vlans *v;
>>   
>> -	if (!br->vlan_enabled)
>> +	/* If filtering was disabled at input, let it pass. */
>> +	if (!BR_INPUT_SKB_CB(skb)->vlan_filtered)
>>   		return true;
>>   
>>   	v = rcu_dereference(p->vlan_info);
>>
> I'm afraid br_should_learn() is not called after calling
> br_allowed_ingress(), so vlan_filtered doesn't seem to be initialized at
> this point.
> 

You are right.  This the local input path so it can still use vlan_enabled. I'll resubmit.

Thanks
-vlad
> Thanks,
> Toshiaki Makita
> 

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html