Pete, thanks for your review. Tim, thanks for your responses. I entered a No 
Objection ballot. I think the general approach of limiting the changes to the 
HTTPS-related ones seems right, and I agree with your argument below about TLS 
validation.

Alissa

> On Apr 8, 2019, at 11:52 AM, Tim Bruijnzeels <[email protected]> wrote:
> 
> Dear Pete,
> 
> Thank you for the review and my apologies for the late reply (I have been 
> moving house).
> 
> Replies in-line.
> 
>> On 22 Mar 2019, at 19:37, Pete Resnick via Datatracker <[email protected]> 
>> wrote:
>> 
>> Reviewer: Pete Resnick
>> Review result: Ready with Issues
>> 
>> I am the assigned Gen-ART reviewer for this draft. The General Area
>> Review Team (Gen-ART) reviews all IETF documents being processed
>> by the IESG for the IETF Chair.  Please treat these comments just
>> like any other last call comments.
>> 
>> For more information, please see the FAQ at
>> 
>> <https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.
>> 
>> Document: draft-ietf-sidrops-https-tal-07
>> Reviewer: Pete Resnick
>> Review Date: 2019-03-22
>> IETF LC End Date: 2019-03-18
>> IESG Telechat date: 2019-04-11
>> 
>> Summary:
>> 
>> I MUST say that this document is quite MUSTy. I only noted those that caused 
>> me
>> confusion or seemed useless. All of these are either minor issues or nits.
>> Either way, the document is generally ready.
>> 
>> Major issues:
>> 
>> None.
>> 
>> Minor issues (or might be nits):
>> 
>> In 2.3:
>> 
>>  The validity interval of this trust anchor SHOULD reflect the
>>  anticipated period of stability...
>> 
>> Are there cases where it wouldn't reflect the period of stability? If so, it
>> would be good to give an example. If not, then s/SHOULD reflect/reflects.
> 
> This is not modified from RFC 7730 - to which I was not an author. I have 
> limited my changes to adding HTTPS support.
> 
> That said, I don't think this should be a SHOULD. In practice Relying Parties 
> will retrieve TA certificates on every validation run, and changes happen at 
> unpredictable intervals.
> 
> I would prefer a text that said:
> 
> The validity interval of this trust anchor is chosen such that the 
> "notBefore" time predates the moment that this certificate is published, and 
> the "notAfter" time is after the planned time of re-issuance of this 
> certificate.
> 
>> 
>> Similarly for:
>> 
>>  Thus, the entity that issues the trust anchor SHOULD issue a
>>  subordinate CA certificate that contains...
>> 
>> In this case, that SHOULD might even be a MUST.
> 
> Also unchanged since 7730.
> 
> In my opinion this whole section makes recommendations and assumptions about 
> operations of a Trust Anchor. But it's not complete, and it does not reflect 
> the operational realities, and there may be other choices that are valid here 
> too.
> 
> It may be worthwhile discussing these things in sidrops, but for now I would 
> propose to make this section a bit less formal.
> 
> So I would suggest:
> 
> CURRENT:
> Because the public key in the TAL and the trust anchor MUST be stable, this 
> motivates operation of that CA in an offline mode. Thus, the entity that 
> issues the trust anchor SHOULD issue a subordinate CA certificate that 
> contains the same INRs (via the use of the "inherit" option in the INR 
> extensions of the subordinate certificate).
> 
> NEW:
> Because the public key in the TAL and the trust anchor MUST be stable, this 
> motivates operation of that CA in an offline mode. In that case a subordinate 
> CA certificate containing the same INRs, or in theory any sub-set of INRs, 
> can be issued  for online operations.
> 
> I suspect though that some of the RFC7730 authors may object to this change.
> 
>> In section 4, in the last full paragraph and the bullets, I'm not at all 
>> clear
>> why these are RECOMMENDEDs and SHOULD [NOT]s. If they're not MUSTs, it seems
>> like you should explain circumstances (at least in general terms) where an
>> implementation would choose to do deviate from these.
>> 
> 
> Personally I would prefer that this document does not try to prescribe how 
> TLS Verification is done. I don't think this is the right place. The current 
> text is based on similar text in section 4.3 of RFC8182, which I co-authored. 
> I don't consider myself an expert on TLS verification - that section is 
> largely based on IESG feedback at the time. 
> 
> I kind of understand where the IESG came from at the time. It's a reference 
> to RFC7525 which is a BCP for this kind of thing, but in my opinion it 
> requires too much in the way of specifying local behaviour (to this RFC). I 
> am not confident that this is the best way - it may not get sufficient 
> review, it may get outdated, and it may be un-implementable.
> 
> In practice Relying Party implementers will use whatever TLS verification is 
> done by the HTTPS client libraries that they use. They will have little 
> control over the exact behaviour. And implementing their own from scratch 
> will most likely make things more brittle and less secure.
> 
> I am open to suggestions :D
> 
> 
>> Nits/editorial comments:
>> 
>> In the introduction, the "SHOULD" seems superfluous; it doesn't indicate some
>> important implementation advice that someone wouldn't otherwise notice in the
>> protocol. But it's a nit if ever there was one.
> 
> ack 
> 
> 
> 
> Thanks
> Tim
> 
> 
>> 
>> 
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