Re: [Cbor] [Gen-art] Genart last call review of draft-ietf-cbor-cddl-control-05

Lars Eggert <> Mon, 18 October 2021 11:00 UTC

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From: Lars Eggert <>
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Date: Mon, 18 Oct 2021 13:59:48 +0300
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Subject: Re: [Cbor] [Gen-art] Genart last call review of draft-ietf-cbor-cddl-control-05
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Theresa, thank you for your review. I have entered a No Objection ballot for this document.


> On 2021-9-16, at 21:12, Theresa Enghardt via Datatracker <> wrote:
> Reviewer: Theresa Enghardt
> Review result: Ready with Nits
> 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
> <>.
> Document: draft-ietf-cbor-cddl-control-05
> Reviewer: Theresa Enghardt
> Review Date: 2021-09-16
> IETF LC End Date: 2021-09-21
> IESG Telechat date: Not scheduled for a telechat
> Summary: This document is fairly clear and concise, and basically ready for
> publication. I noticed a few minor issues and nits that could further enhance
> document clarity.
> Major issues: None.
> Minor issues:
> Section 1:
> Please consider adding a brief description of what a control operator is, how
> it can be used, and what its components are.
> .feature is described as "Detecting feature use in extension points"
> (introduction) VS "indicating the use of a non-basic feature in an instance"
> (abstract) - How can a control operator detect feature use, doesn't it merely
> indicate? If both of these descriptions are meant to conved the same meaning,
> please consider changing the "purpose" of .feature to something like "Name of a
> feature that is used", or, ideally, find a different word to capture what a
> feature is.
> Section 2:
> "CDDL as defined in [RFC8610] does not have any mechanisms to compute
>   literals.  As an 80 % solution, this specification adds three control
>   operators"
> What are the missing 20%? Please consider briefly mentioning the limitations of
> the new operators.
> "Not all tools may be able to work with non-unique targets or controllers."
> Here, "tool" refers to "CDDL tool" as used in RFC8610, correct? If so, please
> consider making all references to "tool" in this document more precise.
> Section 2.3:
> Please consider adding the outcome of the .det operation in the example in
> Figure 3: The definition of dedenting includes "determining the smallest amount
> of left-most blank space (number of leading space characters) in all the
> non-blank lines". If I understand correctly, taking this definition literally,
> the operation ("oid" .det cbor-tags-oid) would result in no space being removed
> at all, because the string "oid" does not contain anly left-most blank spaces.
> But I suspect that the example is intended to show dedenting of the contents of
> the cbor-tags-oid variable. Perhaps I'm missing something about CDDL here that
> was discussed in RFC8610.
> Section 7 (Security considerations):
> Can there be any additional security concerns if CDDL specifications can
> contain ABNF or "arbitrary" features? While this document obviously can't go
> into specifics, maybe it's worth calling out that one needs to pay specific
> attention if these control operators are used.
> Nits/editorial comments:
> Section 2.2
> "concatenating the target text string ""foo"""
> Is foo intended to be in two double quotes, or should there only be one pair of
> quotes?
> Section 3
> "by defining a ".abnf" control operator"
> Should this say 'an ".abnf" control operator' instead?
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