Re: [v6ops] Last Call: <draft-ietf-v6ops-v6-aaaa-whitelisting-implications-08.txt> (Considerations for Transitioning Content to IPv6) to Informational RFC

On 2/20/12 06:32 , Marc Lampo wrote:
> Hello,
> 
> (sorry to be late with my comments, bit overloaded on my side)
> 
> 6.1 Security Considerations - paragraph 2 (on DNSSEC)
> The text states : "there should not be any negative impact on DNSSEC"
> In my opinion, this is *wrong* :
> 

IMHO the following applies.

if you have one zone yeah I agree.

If you have two zones one with aaaa and one without (assuming this is
done with dns views style implementation) you can sign both and they'll
both be valid and complete from the vantage point of a client which
resolves one or the other of them but not both.

this is a traditional split horizon problem. it's just not inside/outside.

joel

> It is correct that, if an AAAA record exists (in a DNSSEC's zone),
> the appropriate RRSIG will be known to authoritative NS's.
> If, via white listing, the decision is taken not to present the AAAA
> record
> (and its signature), this seems OK.
> 
> However : not returning an AAAA record seems identical to : there is no
> AAAA record.
> And that - there is no AAAA record - yields to "Next Secure" changes !
> If no AAAA record exists, for a name, the corresponding NSEC (NSEC3)
> record
> should not hold a reference to AAAA.
> But if that AAAA record does exist, the authoritative NS will have NSEC
> (NSEC3)
> data that shows so.
> 
> A DNSSEC query (ENDS0 + DO set) for AAAA (and the AAAA exists but due to
> whitelisting
> will not be returned), cannot be proven by accompanying (and required)
> NSEC (NSEC3)
> information.
> Hence : this draft will/might make DNSSEC validating name servers fail.
> 
> 
> If you look at 4.3.1.1 (Description of DNS Resolver Whitelisting) in
> detail,
> please observe :
> 1) the caching name server (and "stub resolver") ask 2 queries
>     (there is only one line,
>      but it are two queries : one for "A", one for "AAAA")
> 2) if the caching name server (or stub resolver) performs DNSSEC
> validation,
>     it will never accept a reply of "NODATA" to the query of AAAA
>     (because the NSEC (NSEC3) information will not prove that
> non-existance)
>     ((and the validating name server will repeat the query to all
>       authoritative NS's, looking for a validatable answer))
> 
> (the final result, to the user might be that only the A record is useable
>  - mission accomplished ?
>  But the side effect will be that validating caching name servers will hit
>   *all* authoritative servers for the domain,
>   "in search of" a correctly validating answer.)
> 
> So, while for the end-user, the result might be identical,
> one "security impact" of this approach is
> additional (useless) DNS traffic and
> additional load on authoritative NS's (that implement whitelisting)
> 
> 
> Kind regards,
> 
> Marc Lampo
> Security Officer
> EURid
> 
> 
> -----Original Message-----
> From: The IESG [mailto:iesg-secretary@ietf.org] 
> Sent: 01 February 2012 04:09 PM
> To: IETF-Announce
> Cc: v6ops@ietf.org
> Subject: [v6ops] Last Call:
> <draft-ietf-v6ops-v6-aaaa-whitelisting-implications-08.txt>
> (Considerations for Transitioning Content to IPv6) to Informational RFC
> 
> 
> The IESG has received a request from the IPv6 Operations WG (v6ops) to
> consider the following document:
> - 'Considerations for Transitioning Content to IPv6'
>   <draft-ietf-v6ops-v6-aaaa-whitelisting-implications-08.txt> as an
> Informational RFC
> 
> The IESG plans to make a decision in the next few weeks, and solicits
> final comments on this action. Please send substantive comments to the
> ietf@ietf.org mailing lists by 2012-02-15. Exceptionally, comments may be
> sent to iesg@ietf.org instead. In either case, please retain the
> beginning of the Subject line to allow automated sorting.
> 
> Abstract
> 
> 
>    This document describes considerations for the transition of end user
>    content on the Internet to IPv6.  While this is tailored to address
>    end user content, which is typically web-based, many aspects of this
>    document may be more broadly applicable to the transition to IPv6 of
>    other applications and services.  This document explores the
>    challenges involved in the transition to IPv6, potential migration
>    tactics, possible migration phases, and other considerations.  The
>    audience for this document is the Internet community generally,
>    particularly IPv6 implementers.
> 
> 
> 
> 
> The file can be obtained via
> http://datatracker.ietf.org/doc/draft-ietf-v6ops-v6-aaaa-whitelisting-impl
> ications/
> 
> IESG discussion can be tracked via
> http://datatracker.ietf.org/doc/draft-ietf-v6ops-v6-aaaa-whitelisting-impl
> ications/
> 
> 
> No IPR declarations have been submitted directly on this I-D.
> 
> 
> 
> _______________________________________________
> v6ops mailing list
> v6ops@ietf.org
> https://www.ietf.org/mailman/listinfo/v6ops
> 