netdev - Re: [PATCH net] ipv6: Fix MLD Query message check

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Date:	Wed, 25 Jun 2014 09:29:16 +0800
From:	Hangbin Liu <liuhangbin@...il.com>
To:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
Cc:	network dev <netdev@...r.kernel.org>,
	David Miller <davem@...emloft.net>
Subject: Re: [PATCH net] ipv6: Fix MLD Query message check

2014-06-24 22:27 GMT+08:00 Sergei Shtylyov <sergei.shtylyov@...entembedded.com>:
> Hello.
>
>
> On 06/24/2014 03:50 PM, Hangbin Liu wrote:
>
>> Based on RFC3810 6.2, we also need to check the hop limit and router alert
>> option besides source address.
>
>
>> Signed-off-by: Hangbin Liu <liuhangbin@...il.com>
>> ---
>>   net/ipv6/mcast.c | 14 ++++++++++++--
>>   1 file changed, 12 insertions(+), 2 deletions(-)
>
>
>> diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
>> index 08b367c..fdf7455 100644
>> --- a/net/ipv6/mcast.c
>> +++ b/net/ipv6/mcast.c
>> @@ -1301,8 +1301,18 @@ int igmp6_event_query(struct sk_buff *skb)
>>         len = ntohs(ipv6_hdr(skb)->payload_len) + sizeof(struct ipv6hdr);
>>         len -= skb_network_header_len(skb);
>>
>> -       /* Drop queries with not link local source */
>> -       if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) &
>> IPV6_ADDR_LINKLOCAL))
>> +       /* RFC3810 6.2
>> +        * Upon reception of an MLD message that contains a Query, the
>> node
>> +        * checks if the source address of the message is a valid
>> link-local
>> +        * address, if the Hop Limit is set to 1, and if the Router Alert
>> +        * option is present in the Hop-By-Hop Options header of the IPv6
>> +        * packet.  If any of these checks fails, the packet is dropped.
>> +        */
>> +       if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)
>> ||
>> +                       ipv6_hdr(skb)->hop_limit != 1 ||
>> +                       ipv6_hdr(skb)->nexthdr != NEXTHDR_HOP ||
>> +                       !(IP6CB(skb)->flags & IP6SKB_ROUTERALERT) ||
>> +                       IP6CB(skb)->ra != htons(IPV6_OPT_ROUTERALERT_MLD))
>
>
>    The continuation lines should start exactly under '!' on the broken up
> line.

Ah, thanks for the reminder. I will send a patch v2 later.

Best Regards
Hangbin Liu
>
> WBR, Sergei
>
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