Hi Shumon, On Thu, Apr 09, 2020 at 11:44:30AM -0400, Shumon Huque wrote: > On Thu, Apr 9, 2020 at 1:09 AM Benjamin Kaduk via Datatracker < > nore...@ietf.org> wrote: > > > > > Thanks for this document; it's pretty clear and it's good to have these > > procedures written down in a well-thought-out manner. > > > > Thank you for your review Ben. > > Section 3 > > > > o It may also be the case that a resolver is unable to provide an > > authenticated response because it gave up after a certain number > > of retries or a certain amount of delay. Or that downstream > > clients of the resolver that originated the query timed out > > waiting for a response. > > > > nit: sentence fragment. > > > > Ok, will fix. > > > > > > Section 5 > > > > Since authenticated denial responses are self-contained, NSEC and > > NSEC3 can be used by different providers to serve the same zone. > > Doing so however defeats the protection against zone enumeration > > provided by NSEC3. A better configuration involves multiple > > > > It might be worth a few more words about why this defeats the protection > > against zone enumeration. > > > > Sure (the short summary is that the adversary can just trivially enumerate > the zone by querying the provider that employs NSEC). Will add some text.
Oh! I was misreading this sentence -- I thought that the loss of protection was due to mixing NSEC and NSEC3 and some sort of cross-protocol interaction, but of course this is just the inherent property of any use of NSEC. So maybe s/Doing so/Any use of NSEC/? > Section 6.1, 6.2 > > > > Should we say anything about when it's safe for a new ZSK to be used to > > sign responses? > > > > I think we were largely leaving these timing details to other documents > like RFC 6781, which we assume readers will be familiar with. > > But since we describe pre-publish ZSK rollovers in some detail, we can > probably say something. Per 6781, you need to wait (1) propagation delay > of the ZSK update to all authoritative servers, plus (2) the TTL of the > DNSKEY > RRset. The only aspect that _may_ need to be highlighted, is that for multi > provider, propagation delay now includes the time to propagate to authority > servers of _all_ the providers (which now necessarily includes the > associated > ZSK import operations). > > Section 8 > > > > nit: s/CDNS/CDS/ > > > > Yup, thanks for catching that. There's actually an additional typo there. > So, we need to > replace "CDNS/DNSKEY" with "CDS/CDNSKEY". > > Also, this section feels a bit sparse compared to 6.1 and 6.2. > > > > Okay, let me ponder what might be useful to elaborate on here .. > > Section 9 > > > > In model 2, once initially bootstrapped with each others zone signing > > keys via these API mechanisms, providers could, if desired, > > periodically query each others DNSKEY RRsets and automatically import > > or withdraw ZSKs in the keyset as key rollover events happen. > > > > What kind of authentication would be needed for this > > provider-to-provider API access? > > > > Post bootstrapping (i.e. after the providers were already deployed in a > multi-signer configuration), I don't think there any new authentication > mechanisms needed, since the DNSKEY RRset is already signed and > can be verified by anyone to confirm updated ZSK elements. So, they > could securely discover this using the DNS protocol (rather than vendor > proprietary APIs). > > Section 10 > > > > Shouldn't we have references for DoT and DoH? > > > > Hmm, okay. This was almost a parenthetical comment about a possible > future state of the DNS ecosystem, so it didn't immediately occur to me > add references. But sure, we can add them. > > Section 12 > > > > I think both import and export need to be strongly authenticated, though > > the DNSSEC itself can provide for authentication of export in most > > (all?) cases. If (e.g.) the zone owner fetches bad data and then > > strongly authenticates to shove that bad data into the other services, > > you still end up with bad data in use. > > > > > (Also, integrity protection, though I expect this is implicit.) > > Yes, DNSSEC could be used in many cases, post bootstrapping. But I > expect the zone owner will be using provider API for both export and > import. These are almost always REST/HTTPS so they are strongly > authenticated, and yes integrity protected (and confidentiality protected). > So maybe the easiest thing to do is to mention "import and export" here. That was my first thought, yes. > If using DNS UPDATE, then that is typically strongly authenticated > (e.g. TSIG with HMAC-SHA256 etc) and integrity protected (but not > confidentiality protected, unless using DNS over TLS, which isn't yet > common for UPDATE). > > This is the sort of operation that I'd want to have multi-factor > > authentication for, too. > > > > I can see some more security conscious enterprises doing that, yes. > We can mention that. Thanks! > Section 14.1 > > > > RFCs 2136, 5731 don't currently seem to be cited in a manner that > > requires a normative reference. > > > > Yes, ok. I will promote those references. Thanks for the updates (and the follow-up discussion on ZSK-use timing that I trust will resolve satisfactorily). -Ben _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
