Re: [DNSOP] [Ext] Call for Adoption: draft-hoffman-dnssec-iana-cons

[Paul Wouters <[e-mail]>]

On Tue, 5 Jan 2021, Ben Schwartz wrote:

> One thing I found surprising here is that RFC 6840 Section 5.11 says
>    Validators
>    SHOULD accept any single valid path.  They SHOULD NOT insist that all
>    algorithms signaled in the DS RRset work, and they MUST NOT insist
>    that all algorithms signaled in the DNSKEY RRset work.
> 
> If a validator has more confidence in Algorithm A than Algorithm B, it's frustrating for it to be required to accept a B signature when
> Algorithm A indicates that the record is Bogus.  Do validators actually behave this way, checking each signature until they find a valid one?
> 
> Perhaps if we updated RFC 6840 to indicate that validators should validate only the most-preferred available signature (or indeed insist that
> all supported signatures are valid), that would reduce the level of concern here.  Zones and resolvers could add more algorithms with no risk of
> weakening their security posture.

But it is the zone owner that declares what is acceptable to them for
their domain, by using DS records of the type they want. Why should a
resolver override that?

Also, you would end up building a list of algorithms from worst to best.
This is not always obvious. Sure, the SHA1 vs SHA2 is obvious. Would you
prefer a NIST ECC curve over a GOST ECC curve or not?

DNS RFC's stick to the rule that validators should not be in the space
of determining which crypto algorithm is preferred.

Paul


> On Tue, Jan 5, 2021 at 3:24 AM Василий Долматов <[e-mail]> wrote:
> 
>
>       > 4 янв. 2021 г., в 19:20, Stephen Farrell <[e-mail]> написал(а):
>       >
>       >
>       > Hiya,
>       >
>       > On 04/01/2021 16:05, Paul Wouters wrote:
>       >> While asking is fair, you would also have to define what you
>       >> do based on the outcome of that ask. You left that out,
>       >
>       > I don't think I did omit that. My stated reason to ask was
>       > to help me figure out what I think about the draft named in
>       > the subject line. And yes, I do think that if a codepoint
>       > is being requested for a new version of an existing one
>       > then asking about how the existing one was used is a good
>       > thing to do. The case with gost and rsa+sha1/sha256 isn't
>       > the same because gost is a series of national standards.
>       >
>       > > As to answer your question, I believe GOST did not see
>       > > more than about 5 domains use it in what was clearly a
>       > > "Testing" deployment.
>       >
>       > Thanks. In that case, it sounds like it'd have been better
>       > to use a private or experimental code point for that kind
>       > of thing. OTOH, my understanding (based only on hallway
>       > chats over the years) was that the codepoint was allocated
>       > for political reasons. Either way, does that mean that a
>       > lot of effort to implement and test was wasted since that
>       > codepoint was allocated? If so, avoiding that in future
>       > would be good, if there's a way to do that.
>       The situation with GOST in DNSSEC is explainable and was explained
>       in the list during the discussion of another draft (and to you personally, AFAIR,
>       maybe you’ve forgotten that).
>
>       To the time when RFC5933 was published and corresponding codepoint was allocated
>       it has been known already that new version of underlying standards for hash and signature were on the way,
>       so there were no reason to implement it immediately using standards which will be obsoleted soon.
>
>       That explains why there  were only several test implementations performed, which were intended to check
>       smooth interoperability, if different algorithms were used in DNSSEC validation chain, with even several
>       algorithms switches along the chain.  The interoperability was proven and results were presented on
>       one of the RIPE meetings.
>
>       Then the DNSSEC deployment in Russia went into «waiting state», waiting for:
>        - new standards to be published in Russia
>        - reference implementations of it were created  by different software teams with interoperability checks
>        - making IETF community aware of them by publishing set of Informational RFC
>        - «running code» was created for new standards in open-source software (implementing it in OpenSSL for instance)
>        - assigning codepoints in DNSSEC registry
>
>       Now we are at the last step in this list, and after its completion we consider that it will become possible to deploy GOST in
>       DNSSEC.
>
>       That explains why there is no wide deployment of GOST in DNSSEC until now. We prefer slow-pace but reliable way forward.
>
>       Btw, the same way was passed for TLS now, after codepoints for GOST in TLS has been assigned already, we have
>       several different implementations of TLS with GOST by different software developer teams and we have a stand for TLS
>       interoperability check which is run by the team independent from any of software vendors and performing the check that all
>       implementations are mutually compatible and aligned with the corresponding RFCs.
>       This stand  is used for the interoperability check of IPSEC implementations also and will incorporate DNSSEC in its scope in proper
>       time.
>
>       dol@
>
>       >
>       > Cheers,
>       > S.
>       >
>       > PS: note that I'm neither supporting, nor objecting to,
>       > Paul's draft in the above.
>       >
>       >
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