Re: [secdir] [DNSOP] Secdir last call review of draft-ietf-dnsop-server-cookies-04
Stephen Farrell <stephen.farrell@cs.tcd.ie> Wed, 02 December 2020 21:49 UTC
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To: Willem Toorop <willem@nlnetlabs.nl>, Ondřej Surý <ondrej@isc.org>
Cc: last-call@ietf.org, draft-ietf-dnsop-server-cookies.all@ietf.org, dnsop@ietf.org, secdir@ietf.org
References: <160693121881.9413.5642470305677631145@ietfa.amsl.com> <17AFD6F5-11DA-41BC-8C37-E1893648041D@isc.org> <75c266ba-573a-29e3-621d-aea9b27f195f@cs.tcd.ie> <b23d3f2b-4b4f-f70c-ff53-cbd2c229a887@nlnetlabs.nl>
From: Stephen Farrell <stephen.farrell@cs.tcd.ie>
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Date: Wed, 02 Dec 2020 21:49:15 +0000
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Subject: Re: [secdir] [DNSOP] Secdir last call review of draft-ietf-dnsop-server-cookies-04
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Hiya, On 02/12/2020 21:38, Willem Toorop wrote: > Op 02-12-2020 om 21:37 schreef Stephen Farrell: > > <snip> > >>> ad 2) we need a value that’s synchronized well enough and monotonic. >>> I honestly don’t see any value in using 64-bit value here. Using >>> unixtime has a value in itself, it’s a well-known and there’s a >>> little room for any implementer to make a mistake in an >>> implementation. The interoperability is more important than the >>> actual value of the counter. It’s write only counter, nobody is going >>> to interpret it after it has been generated, and it’s wide enough to >>> prevent brute forcing. >> >> So what happens after 2038? That's really not v. far in the >> future any more. > > The draft states that `All comparisons involving these fields MUST > use "Serial number arithmetic", as defined in [RFC1982]'. So it can not > be used to compare differences larger than 68 years, but comparisons of > cookie timestamps are more in the "hours" order of magnitude. Sorry for being dim, but is clear what value to put in those 4 octets in say 2039 such that different implementations will do the right thing? I did glance at rfc1982, so there may be very far-sighted text in there that I missed:-) And it may even be fine for this purpose if different servers differ by a second or so at that point, but even if so, it may be a bad plan to leave that unspecified in case other timestamps use the same code. Cheers, S. > > Cheers, > -- Willem > >> >> Cheers, >> S. >> >>> >>> Cheers, Ondřej -- Ondřej Surý — ISC (He/Him) >>> >>>> On 2. 12. 2020, at 18:47, Stephen Farrell via Datatracker >>>> <noreply@ietf.org> wrote: >>>> >>>> Reviewer: Stephen Farrell Review result: Has Issues >>>> >>>> I see two issues here worth checking: >>>> >>>> 1. I don't recall SipHash being used as a MAC in any IETF standard >>>> before. We normally use HMAC, even if truncated. Why make this >>>> change and was that checked with e.g. CFRG? (And the URL given in >>>> the reference gets me a 404.) >>>> >>>> 2. Is it really a good idea to use a 32 bit seconds since >>>> 1970-01-01 in 2020? I'd have thought that e.g. a timestamp in hours >>>> since then or seconds since some date in 2020 would be better. >>>> >>>> Here's a couple of nits too: - section 1: what's a "strong >>>> cookie"? - "gallimaufry" - cute! but not sure it'll help readers to >>>> learn that word. >>>> >>>> >>>> >>>> >>> >>> _______________________________________________ DNSOP mailing list >>> DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop >>> >> >> _______________________________________________ >> DNSOP mailing list >> DNSOP@ietf.org >> https://www.ietf.org/mailman/listinfo/dnsop >> > > _______________________________________________ > DNSOP mailing list > DNSOP@ietf.org > https://www.ietf.org/mailman/listinfo/dnsop >
- [secdir] Secdir last call review of draft-ietf-dn… Stephen Farrell via Datatracker
- Re: [secdir] Secdir last call review of draft-iet… Ondřej Surý
- Re: [secdir] [DNSOP] Secdir last call review of d… Stephen Farrell
- Re: [secdir] Secdir last call review of draft-iet… Eric Rescorla
- Re: [secdir] [DNSOP] Secdir last call review of d… Willem Toorop
- Re: [secdir] [DNSOP] Secdir last call review of d… Stephen Farrell
- Re: [secdir] [DNSOP] Secdir last call review of d… Willem Toorop
- Re: [secdir] Secdir last call review of draft-iet… Ondřej Surý
- Re: [secdir] [DNSOP] Secdir last call review of d… Brian Dickson
- Re: [secdir] [Last-Call] [DNSOP] Secdir last call… Stephen Farrell
- Re: [secdir] [Last-Call] [DNSOP] Secdir last call… Willem Toorop
- Re: [secdir] [DNSOP] [Last-Call] Secdir last call… Eric Rescorla
- Re: [secdir] [Last-Call] [DNSOP] Secdir last call… Salz, Rich
- Re: [secdir] [Last-Call] [DNSOP] Secdir last call… Eric Rescorla
- Re: [secdir] Secdir last call review of draft-iet… Benjamin Kaduk
- Re: [secdir] Secdir last call review of draft-iet… Ondřej Surý
- Re: [secdir] [DNSOP] Secdir last call review of d… Brian Dickson
- Re: [secdir] [Last-Call] Secdir last call review … Salz, Rich
- Re: [secdir] [DNSOP] [Last-Call] Secdir last call… Stephen Farrell
- Re: [secdir] [DNSOP] [Last-Call] Secdir last call… Salz, Rich
- Re: [secdir] [DNSOP] [Last-Call] Secdir last call… Eric Rescorla
- Re: [secdir] Secdir last call review of draft-iet… Benjamin Kaduk
- Re: [secdir] [DNSOP] Secdir last call review of d… Stephen Farrell