Re: [PATCH] netfilter: Checksum of an IPv6 UDP packet is mandatory

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Sat, Jun 29, 2013 at 12:15:19AM +0800, Changli Gao wrote:
> Checksum of an IPv6 UDP packet is mandatory.

There is some discussion on this:

http://tools.ietf.org/html/rfc6936

"The inability to use an IPv6 datagram with a zero UDP checksum has
 been found to be a real problem for certain classes of application,
 primarily tunnel applications."

> ---
>  net/netfilter/nf_conntrack_proto_udp.c |    9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c
> index 9d7721c..31dc854 100644
> --- a/net/netfilter/nf_conntrack_proto_udp.c
> +++ b/net/netfilter/nf_conntrack_proto_udp.c
> @@ -134,8 +134,15 @@ static int udp_error(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
>  	}
>  
>  	/* Packet with no checksum */
> -	if (!hdr->check)
> +	if (!hdr->check) {
> +		if (pf == PF_INET6) {
> +			if (LOG_INVALID(net, IPPROTO_UDP))
> +				nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
> +					       "nf_ct_udp: bad UDP checksum ");
> +			return -NF_ACCEPT;
> +		}
>  		return NF_ACCEPT;
> +	}
>  
>  	/* Checksum invalid? Ignore.
>  	 * We skip checking packets on the outgoing path
> -- 
> 1.7.9.5
>