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

["Marc Lampo" <[e-mail]>]

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* :


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:[e-mail]] 
Sent: 01 February 2012 04:09 PM
To: IETF-Announce
Cc: [e-mail]
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
[e-mail] mailing lists by 2012-02-15. Exceptionally, comments may be
sent to [e-mail] 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.