On Tue, May 9, 2017 at 3:56 PM, Gene Shuman <[email protected]> wrote:
> I've taken a look at the proposed draft and have a few notes as well. > > 4. The currently specified limits on i= are not included MUST >10, SHOULD > > 50, etc > > 5.1 - In the current draft, it's mandated that AMS must use relaxed header > canonicalization, but that's missing from the proposed draft > I think that 5.1.2 in the current draft is wrong, it's overridden by 5.1.2.1.2. We started out only allowing relaxed, but then added back support for c= in a later draft. Brandon 5.2 - I'm a bit confused by the comment noting the importance of i=2. What > is it that you're intending there? > > 5.3.1 - typo: one of three possible values: -> one of *four* possible > values > > 7.2 - It may be worth elaborating more on the possible ways in which > cv=invalid can arise, if not here, maybe somewhere else > > 7.4 - In general I prefer this to the psuedo code in the current draft, > but I think it could still use a bit of work. In particular, sections C-H > are exactly describing how to validate a DKIM signature and seems somewhat > unnecessary. Is there any particular reason you decided to include this, as > opposed to just relying on the DKIM spec for this? > > 7.5 - typo: no -> all > > In general though, I agree with Brandon, the proposed draft definitely > makes some things clearer, which I think is a step in the right direction. > > =Gene > > > On Tue, May 9, 2017 at 2:04 PM, Brandon Long <[email protected]> wrote: > >> In 5.1 defining the AMS, you say that it should cover DKIM-Signature and >> AuthRes headers. In particular, AuthRes headers are expected to be removed >> by ADMDs, especially if the message transits the same ADMD multiple times. >> Also, the information in the AuthRes header is superseded by the ArcAuthRes >> header. Including it means an arbitrary AMS breakage for something pretty >> minor, so I would recommend to not include it. >> >> Our implementation explicitly blacklists that header. >> >> I know some mailing lists also strip the DKIM-Signature header, but since >> they are likely to break the AMS anyways, that's less important. I'm not >> sure what the benefit is to including it, but it seems harmless. In >> particular, if the DKIM-Signature still passes, then the ARC isn't adding >> that much, and removing the DKIM-Signature header doesn't mean all that >> much either since it's validity was already assessed and that assessment >> included in the AAR. We don't blacklist the DKIM-Signature method in our >> implementation, but I don't understand the advisement. >> >> You also talk about "responsibility". I'm not sure that's how I would >> describe it. An ARC hop is documenting that a message passed through it, >> and that it evaluated the authentication of the message. The only >> responsibility of a hop is to correctly validate the SPF/DKIM/ARC >> information, there is no ownership implied over the message itself. >> >> With AMS, you can answer the question: which ADMD is the last ADMD to >> have modified the message. I guess in that sense, the last modifier is >> "responsible" for the current state of the message... but that kind of >> means that the AMS of previous hops allows them to disown responsibility >> for the current state of the message... >> >> 5.2 - should we point out that there should be only one of these per >> hop? The openspf/dkim/dmarc implementations tend to add separate AuthRes >> headers for each evaluation, but ARC requires those to be a single instance. >> >> 5.3.1 - none as defined as "arrives at an MTA from an MSA", perhaps my >> understanding of those terms is slightly odd, but I would think that an MSA >> usually uses an MTA to actually send the message, and it isn't that >> "sending" MTA that's the first hop, it should be the first "receiving" >> MTA. I mean, that's usually the point at which the DKIM signature is >> applied, and the SPF would be "from" there, not based on the location of >> the MUA. >> >> There are some missing pieces here, corresponding to the current draft >> sections 5.4 (alternate signing algorithms), 6.4.3 (arc email >> authentication method for AuthRes), 6.4.5 for dmarc xml. I see that the >> arc is included in your IANA section, not sure if the call out outside of >> the definition is necessary or not. >> >> Overall, I think your draft makes some things clearer, and some things in >> the original are clearer. It's worth looking into either combining or >> choosing. >> >> >> Brandon >> >> On Thu, May 4, 2017 at 12:56 AM, Murray S. Kucherawy <[email protected] >> > wrote: >> >>> Colleagues, >>> >>> As I progress (slowly, alas) toward completing my sample implementation >>> of OpenARC, I've found myself taking a lot of notes about the current >>> draft. This has helped me make progress; in some cases it became things I >>> posted to the list, and in others it was just to help or confirm my >>> understanding of the protocol. >>> >>> I have developed this enough to become a fairly comprehensive >>> alternative text to the current draft. I find the layout of this version >>> to flow better for my own purposes, and in a few places I've tried to >>> clarify some of the material by rewriting chunks of it. None of this is >>> meant to assert that the current draft is deficient; I've just found it to >>> be a helpful exercise for me. >>> >>> I offer it here to the WG as a contribution; the WG of course is free to >>> use some, all, or none of it as it wishes. >>> >>> http://blackops.org/~msk/draft-kucherawy-dmarc-arc-base.txt >>> >>> If it would be more helpful to post this as an I-D, please let me know. >>> >>> -MSK >>> >>> _______________________________________________ >>> dmarc mailing list >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/dmarc >>> >>> >> >> _______________________________________________ >> dmarc mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/dmarc >> >> >
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