Re: [dns-privacy] Stephen Farrell's Discuss on draft-ietf-dprive-dnsodtls-13: (with DISCUSS and COMMENT)

Revised draft https://tools.ietf.org/html/draft-ietf-dprive-dnsodtls-14 addresses DISCUSS points and comments received during ISEG review. 

Please have a look.

Cheers,
-Tiru

> -----Original Message-----
> From: Tirumaleswar Reddy (tireddy)
> Sent: Thursday, December 15, 2016 2:03 PM
> To: 'Stephen Farrell' <stephen.farrell@cs.tcd.ie>; The IESG <iesg@ietf.org>
> Cc: tjw.ietf@gmail.com; dns-privacy@ietf.org; draft-ietf-dprive-
> dnsodtls@ietf.org; dprive-chairs@ietf.org
> Subject: RE: [dns-privacy] Stephen Farrell's Discuss on draft-ietf-dprive-
> dnsodtls-13: (with DISCUSS and COMMENT)
> 
> > -----Original Message-----
> > From: Stephen Farrell [mailto:stephen.farrell@cs.tcd.ie]
> > Sent: Thursday, December 15, 2016 1:51 PM
> > To: Tirumaleswar Reddy (tireddy) <tireddy@cisco.com>; The IESG
> > <iesg@ietf.org>
> > Cc: tjw.ietf@gmail.com; dns-privacy@ietf.org; draft-ietf-dprive-
> > dnsodtls@ietf.org; dprive-chairs@ietf.org
> > Subject: Re: [dns-privacy] Stephen Farrell's Discuss on
> > draft-ietf-dprive-
> > dnsodtls-13: (with DISCUSS and COMMENT)
> >
> >
> > Hiya,
> >
> > On 15/12/16 05:15, Tirumaleswar Reddy (tireddy) wrote:
> > > Hi Stephen,
> > >
> > > I missed responding to following comment:
> > >
> > >> But 0RTT is replayable, which iirc is particularly dangerous for
> > >> foo/DTLS/UDP with anycast and if the attacker can see the upstream
> > >> queries from an anycast instance with an empty cachce at which the
> > >> attacker has targetted a replayed query. So the text in (4) needs a
> > >> bit of work I think. (Though it's possible I'm remembering this
> > >> stuff badly;-)
> > >
> > > Good point, will add the following additional text to [4]:
> > >
> > > DNS query sent using 0-RTT key might be replayed by an attacker and
> > > if the anycast instance does not have the resource record cached,
> > > and the triggered recursive process of going through the
> > > authoritative DNS hierarchy can be used by the attacker to determine
> > > the encrypted DNS query resulting in privacy leak through DNS.
> >
> > Doesn't the above end up meaning: "don't use 0RTT with DNS/DTLS1.3"?
> 
> Yes :)
> 
> >
> > I think this may have been raised on the dprive or tls wg lists a year
> > or so ago when we were trying to figure out the consequences of 0RTT.
> > Would be worthwhile checking that to ensure any text put in here is
> > consistent with that analysis.
> 
> In DPRIVE WG, TLS 1.3 was discussed but not the attack you pointed out.
> I will remove the text related to this mode and will start a discussion in the WG
> on usage of 0-RTT mode.
> 
> -Tiru
> 
> >
> > S.
> >
> > >
> > > -Tiru
> > >
> > > _______________________________________________ dns-privacy
> mailing
> > > list dns-privacy@ietf.org
> > > https://www.ietf.org/mailman/listinfo/dns-privacy
> > >