netdev - Re: [PATCH] ipv6: add anti-spoofing checks for 6to4 and 6rd

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Message-ID: <50F9F875.30302@linux-ipv6.org>
Date:	Sat, 19 Jan 2013 10:35:49 +0900
From:	YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
To:	netdev@...r.kernel.org, davem@...emloft.net,
	hannes@...essinduktion.org
CC:	YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
Subject: Re: [PATCH] ipv6: add anti-spoofing checks for 6to4 and 6rd

(2013年01月19日 05:04), Hannes Frederic Sowa wrote:
> This patch adds anti-spoofing checks in sit.c as specified in RFC3964
> section 5.2 for 6to4 and RFC5969 section 12 for 6rd. I left out the
> checks which could easily be implemented with netfilter.
> 
> Specifically this patch adds following logic (based loosely on the
> pseudocode in RFC3964 section 5.2):
> 
> if prefix (inner_src_v6) == rd6_prefix (2002::/16 is the default)
>         and outer_src_v4 != embedded_ipv4 (inner_src_v6)
>                 drop
> if prefix (inner_dst_v6) == rd6_prefix (or 2002::/16 is the default)
>         and outer_dst_v4 != embedded_ipv4 (inner_dst_v6)
>                 drop
> accept
> 
> To accomplish the specified security checks proposed by above RFCs,
> it is still necessary to employ uRPF filters with netfilter. These new
> checks only kick in if the employed addresses are within the 2002::/16 or
> another range specified by the 6rd-prefix (which defaults to 2002::/16).

It seems this breaks 6rd receiving rules:

BR:
	if (outer src ip4 != embedded src ip4)
		drop();
CE:
	if (outer src ip4 != embedded src ip4 ||
	    inner dest ip6 != configured ip6 prefix)
		drop();

No?

--yoshfuji
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