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RE: AH and flow label



I agree with Brian. I'd like to see it protected. 

Hesham

-----Original Message-----
From: ipv6-bounces@ietf.org [mailto:ipv6-bounces@ietf.org]On Behalf Of
Brian Haberman
Sent: Friday, September 10, 2004 6:50 AM
To: Francis Dupont
Cc: ipv6@ietf.org
Subject: Re: AH and flow label


Speaking as an IPv6 wg member, I am not comfortable with the flow label 
being
unprotected.  As an immutable field, it should be included in the ICV 
calculation.
I have seen several projects started that intend on taking advantage of 
RFC 3697.
My main question is how much of an impact would such a change have on
the existing IPv6 implementations.

Can anyone speak to their IPv6/IPSec implementations on this issue?

Regards,
Brian

On Sep 10, 2004, at 4:49, Francis Dupont wrote:

> Here is a message from Steve Kent who is updating the RFC 2402
> "IP Authentication Header (AH)" about the flow label status.
> I have put it in this list for people interested by IPsec but
> who have no enough time to read the mailing list...
> To summary the question is:
>
> Is the [ipsec] WG comfortable with the status quo, i.e., NOT including 
> the
> flow label in the ICV [integrity check value], despite the fact that it
> is immutable?
>
> Francis.Dupont@enst-bretagne.fr
>
> PS: of course my opinion is we have to keep the status quo and
> the decision is in the scope (i.e., hands?) of the ipv6 WG.
>
> From: Stephen Kent <kent@bbn.com>
> Date: September 9, 2004 14:58:36 EDT
> To: Francis Dupont <Francis.Dupont@enst-bretagne.fr>
> Cc: ipsec@lists.tislabs.com
> Subject: Re: [Ipsec] draft-ietf-ipsec-rfc2402bis-07.txt ... Suggest 
> moving the "Flow Label" IPv6 base header field to "immutable" and 
> protecting with AH
>
>
> Francis,
>
> I looked at RFC 3697.  It does state that AH does not protect flow 
> labels, which is consistent with the old AH spec (RFC 2402). So, if we 
> were to change this in the new AH spec, there would be a conflict. 
> Also, the security analysis in 3697 argues that since there is no 
> protection of the flow spec value, intermediate systems cannot rely on 
> it and an end IPsec implementation cannot rely on it in transport 
> mode.  I agree that it is unlikely that we would be able to manage key 
> distribution for intermediate systems to be able to check the AH ICV, 
> which supports your argument that it is not worth including it in the 
> ICV computation.
> However, if we choose to maintain backward compatibility with 2402, we 
> need to clarify in 2402bis that this is the reason for not including 
> the value in the ICV computation, as opposed to the current, erroneous 
> rationale.
>
> Is the WG comfortable with the status quo, i.e., NOT including the 
> flow label in the ICV, despite the fact that it is immutable?
>
> Steve
>
>
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