Relaxed Packet Counter Verification for Babel MAC Authentication
draft-ietf-babel-mac-relaxed-05

Received changes through RFC Editor sync (changed state to RFC, created became rfc relationship between draft-ietf-babel-mac-relaxed and RFC 9467, changed IESG state to RFC Published)

[Ballot comment]
# GEN AD review of draft-ietf-babel-mac-relaxed-04

CC @larseggert

Thanks to Stewart Bryant for the General Area Review Team (Gen-ART) review
(https://mailarchive.ietf.org/arch/msg/gen-art/aNc5ylceFw8dsLWBPxoFDGU5xVw).

## Comment

### Missing "Updates" explanation

This document updates RFC8967, but does not seem to include explanatory text
about this in the abstract.

## Nits

All comments below are about very minor potential issues that you may choose to
address in some way - or ignore - as you see fit. Some were flagged by
automated tools (via https://github.com/larseggert/ietf-reviewtool), so there
will likely be some false positives. There is no need to let me know what you
did with these suggestions.

### Stray characters

The text version of this document contains these HTML entities, which might
indicate issues with its XML source: `ö`

## Notes

This review is in the ["IETF Comments" Markdown format][ICMF], You can use the
[`ietf-comments` tool][ICT] to automatically convert this review into
individual GitHub issues. Review generated by the [`ietf-reviewtool`][IRT].

[ICMF]: https://github.com/mnot/ietf-comments/blob/main/format.md
[ICT]: https://github.com/mnot/ietf-comments
[IRT]: https://github.com/larseggert/ietf-reviewtool

[Ballot comment]
Thanks to Christian Huitema for the excellent secdir review.

The abstract should state this document Updates RFC 8967

Suggestion:

        This document updates RFC 8967 by relaxing packet
        verification rules defined [...]

[Ballot comment]
Thank you to Christian Huitema for the SECDIR review.

** Section 3.1.  In this updated text, there doesn’t appear to be an explicit explanation that PCm is the multicast counter and the PCu is the unicast counter.

** Section 4.  I concur with Christian Huitema’s SECDIR recommendation to add clarifying text on why multiple PCs aren’t an issue.  Extracting from the review with editorial liberty:

OLD
The procedures described in this document do not change the security properties described in Section 1.2 of RFC 8967.

NEW
The procedures described in this document do not change the security properties described in Section 1.2 of RFC 8967.  Since unicast and multicast packets can be reliably distinguished by examining the destination IP address (which is copied in the pseudo-header included in the computation of the MAC TLV), the use of separate PCs does not allow an on-path adversary to capture a unicast packet with a PC TLV larger than the highest multicast PC TLV, and replay it as a multicast packet (or vice versa).

** Section 4.  Given this opportunity to update RFC8967, the SECDIR reviewer points out an opportunity to note an attack via a compromised node and that the attacks through compromised node or compromised credential can persist until they are detected and the network administrator restarts the network using new credentials.  Considering adding such cautionary text.

[Ballot comment]
One nit, which requires no reply: the first sentence in the Introduction makes two statements and then says that “this assumption” is not valid. Perhaps rearrange to make it clear what is invalid?

[Ballot comment]
One nit, which requires no reply: the first sentence makes two statements and then says that “this assumption” is not valid. Perhaps rearrange to make it clear what is invalid?

[Ballot comment]
Thanks for working on this update. Thanks to Kyle Rose for the TSVART review.

I have one comment and I believe it will improve the document if addressed -

- Maintaining Multiple highest PC is RECOMMENDED and window-based validation is OPTIONAL. It would be very helpful to explain the reasoning behind these choices for the implementers.

[Ballot comment]
Thank you for writing this document - in addition to explaining the problem nicely, it is well written and explains the solution nicely.
Thank you

[Ballot comment]
The RECOMMENDED in Section 3.2 is curious, especially since it's referring to the default value.  Do we need any guidance here about when one might legitimately pick a different value?  Or what's the impact if I pick something else such that a BCP 14 keyword is needed here?

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Functions Operator has reviewed draft-ietf-babel-mac-relaxed-04, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any registry actions.

While it's often helpful for a document's IANA Considerations section to remain in place upon publication even if there are no actions, if the authors strongly prefer to remove it, we do not object.

If this assessment is not accurate, please respond as soon as possible.

For definitions of IANA review states, please see:

https://datatracker.ietf.org/help/state/draft/iana-review

Thank you,

David Dong
IANA Services Specialist

The following Last Call announcement was sent out (ends 2023-04-18):

From: The IESG
To: IETF-Announce
CC: andrew-ietf@liquid.tech, babel-chairs@ietf.org, babel@ietf.org, d3e3e3@gmail.com, draft-ietf-babel-mac-relaxed@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Relaxed Packet Counter Verification for Babel MAC Authentication) to Proposed Standard


The IESG has received a request from the Babel routing protocol WG (babel) to
consider the following document: - 'Relaxed Packet Counter Verification for
Babel MAC Authentication'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
last-call@ietf.org mailing lists by 2023-04-18. Exceptionally, comments may
be sent to iesg@ietf.org instead. In either case, please retain the beginning
of the Subject line to allow automated sorting.

Abstract


  This document relaxes packet verification rules defined in the Babel
  MAC Authentication protocol in order to make it more robust in the
  presence of packet reordering.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-babel-mac-relaxed/



No IPR declarations have been submitted directly on this I-D.

1. Does the working group (WG) consensus represent the strong concurrence
of a few individuals, with others being silent, or did it reach broad
agreement?

  There is solid support for this draft in the WG.

2. Was there controversy about particular points, or were there decisions
where the consensus was particularly rough?

  No.

3. Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarize the areas of conflict in separate
email messages to the responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.)

  No.

4. For protocol documents, are there existing implementations of the
contents of the document? Have a significant number of potential
implementers indicated plans to implement? Are any existing
implementations reported somewhere, either in the document itself (as
RFC 7942 recommends) or elsewhere (where)?

  There are two independent implementations, babeld and BIRD. See
https://mailarchive.ietf.org/arch/msg/babel/W5k5WNWp4A6KuOUmmrlvCPY-wr4/

5. Does this document need review from other IETF working groups or
external organizations?

  No.

6. Describe how the document meets any required formal expert review
criteria, such as the MIB Doctor, YANG Doctor, media type, and URI
type reviews.

  An early RTGDIR review was done as posted here
  https://mailarchive.ietf.org/arch/msg/rtg-dir/ilzmanO9BZapxLGmiSMgNnYvgUk/
  The comments in that review has been resolved.

7. If the document contains a YANG module, has the final version of
the module been checked with any of the recommended validation tools
for syntax and formatting validation? If there are any resulting
errors or warnings, what is the justification for not fixing them at
this time? Does the YANG module comply with the Network Management
Datastore Architecture (NMDA) as specified in RFC 8342?

  This document contains no YANG modules.

8. Describe reviews and automated checks performed to validate
sections of the final version of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, CBOR's CDDL,
ASN.1 modules, etc.  Document Shepherd Checks.

  This document contains no formal language. The Shepherd has
  carefully reviewed this draft a few times, most recently as
  documented at
https://mailarchive.ietf.org/arch/msg/babel/HQjK4TKnEqC-yI8YPt3De5QOm2g/
  These comments have been resolved.

9. Based on the shepherd's review of the document, is it their opinion
that this document is needed, clearly written, complete, correctly
designed, and ready to be handed off to the responsible Area Director?

  Yes.

10. Several IETF Areas have assembled lists of common issues that
their reviewers encounter. Do any such issues remain that would merit
specific attention from subsequent reviews?

  Not that I can see..

11. What type of RFC publication is being requested on the IETF stream
(Best Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental, or Historic)? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this
intent?

  Standards Track as indicated on the title page. This is appropriate
  for a document that updates a Standards Track protocol (RFC 8967).

12. Has the interested community confirmed that any and all
appropriate IPR disclosures required by BCP 78 and BCP 79 have been
filed? If not, explain why. If yes, summarize any discussion and
conclusion regarding the intellectual property rights (IPR)
disclosures, including links to relevant emails.

  See IPR statments at
https://mailarchive.ietf.org/arch/msg/babel/MBKqQLx-rzKIvCBXXudpnjv1RY8/
https://mailarchive.ietf.org/arch/msg/babel/1Y9YGWKViPRsI_3GdoD4rlcRN4Y/
  It appears that no IPR is being claimed.

13. Has each Author or Contributor confirmed their willingness to be
listed as such? If the number of Authors/Editors on the front page is
greater than 5, please provide a justification.

  Implicitly as per question 12 above.

14. Identify any remaining I-D nits in this document. (See the idnits
tool and the checkbox items found in Guidelines to Authors of
Internet-Drafts). Simply running the idnits tool is not enough; please
review the entire guidelines document.

  The nits check incorrectly complains about "non-ASCII" characters in
  the draft. The draft correctly contains characters such as é and ø.

15. Should any informative references be normative or vice-versa?

  I believe the references are correctly categorized.

16. List any normative references that are not freely available to
anyone. Did the community have sufficient access to review any such
normative references?

  All normative references are to RFCs.

17. Are there any normative downward references (see RFC 3967, BCP
97)? If so, list them.

  There are no downward references.

18. Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If they exist, what
is the plan for their completion?

  There are no such reference.

19. Will publication of this document change the status of any
existing RFCs? If so, does the Datatracker metadata correctly reflect
this and are those RFCs listed on the title page, in the abstract, and
discussed in the introduction? If not, explain why and point to the
part of the document where the relationship of this document to these
other RFCs is discussed.

  This document does not change the status of any other RFC but it
  does Update RFC 8967.

20. Describe the document shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of
the document. Confirm that all aspects of the document requiring IANA
assignments are associated with the appropriate reservations in IANA
registries. Confirm that any referenced IANA registries have been
clearly identified. Confirm that each newly created IANA registry
specifies its initial contents, allocations procedures, and a
reasonable name (see RFC 8126).

  This document requires no IANA actions.

21. List any new IANA registries that require Designated Expert Review
for future allocations. Are the instructions to the Designated Expert
clear? Please include suggestions of designated experts, if
appropriate.

  This document creates no IANA registries.

1. Does the working group (WG) consensus represent the strong concurrence
of a few individuals, with others being silent, or did it reach broad
agreement?

  There is solid support for this draft in the WG.

2. Was there controversy about particular points, or were there decisions
where the consensus was particularly rough?

  No.

3. Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarize the areas of conflict in separate
email messages to the responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.)

  No.

4. For protocol documents, are there existing implementations of the
contents of the document? Have a significant number of potential
implementers indicated plans to implement? Are any existing
implementations reported somewhere, either in the document itself (as
RFC 7942 recommends) or elsewhere (where)?

  There are two independent implementations, babeld and BIRD. See
https://mailarchive.ietf.org/arch/msg/babel/W5k5WNWp4A6KuOUmmrlvCPY-wr4/

5. Does this document need review from other IETF working groups or
external organizations?

  No.

6. Describe how the document meets any required formal expert review
criteria, such as the MIB Doctor, YANG Doctor, media type, and URI
type reviews.

  An early RTGDIR review was done as posted here
  https://mailarchive.ietf.org/arch/msg/rtg-dir/ilzmanO9BZapxLGmiSMgNnYvgUk/
  The comments in that review has been resolved.

7. If the document contains a YANG module, has the final version of
the module been checked with any of the recommended validation tools
for syntax and formatting validation? If there are any resulting
errors or warnings, what is the justification for not fixing them at
this time? Does the YANG module comply with the Network Management
Datastore Architecture (NMDA) as specified in RFC 8342?

  This document contains no YANG modules.

8. Describe reviews and automated checks performed to validate
sections of the final version of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, CBOR's CDDL,
ASN.1 modules, etc.  Document Shepherd Checks.

  This document contains no formal language. The Shepherd has
  carefully reviewed this draft a few times, most recently as
  documented at
https://mailarchive.ietf.org/arch/msg/babel/HQjK4TKnEqC-yI8YPt3De5QOm2g/
  These comments have been resolved.

9. Based on the shepherd's review of the document, is it their opinion
that this document is needed, clearly written, complete, correctly
designed, and ready to be handed off to the responsible Area Director?

  Yes.

10. Several IETF Areas have assembled lists of common issues that
their reviewers encounter. Do any such issues remain that would merit
specific attention from subsequent reviews?

  Not that I can see..

11. What type of RFC publication is being requested on the IETF stream
(Best Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental, or Historic)? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this
intent?

  Standards Track as indicated on the title page. This is appropriate
  for a document that updates a Standards Track protocol (RFC 8967).

12. Has the interested community confirmed that any and all
appropriate IPR disclosures required by BCP 78 and BCP 79 have been
filed? If not, explain why. If yes, summarize any discussion and
conclusion regarding the intellectual property rights (IPR)
disclosures, including links to relevant emails.

  See IPR statments at
https://mailarchive.ietf.org/arch/msg/babel/MBKqQLx-rzKIvCBXXudpnjv1RY8/
https://mailarchive.ietf.org/arch/msg/babel/1Y9YGWKViPRsI_3GdoD4rlcRN4Y/
  It appears that no IPR is being claimed.

13. Has each Author or Contributor confirmed their willingness to be
listed as such? If the number of Authors/Editors on the front page is
greater than 5, please provide a justification.

  Implicitly as per question 12 above.

14. Identify any remaining I-D nits in this document. (See the idnits
tool and the checkbox items found in Guidelines to Authors of
Internet-Drafts). Simply running the idnits tool is not enough; please
review the entire guidelines document.

  The nits check incorrectly complains about "non-ASCII" characters in
  the draft. The draft correctly contains characters such as é and ø.

15. Should any informative references be normative or vice-versa?

  I believe the references are correctly categorized.

16. List any normative references that are not freely available to
anyone. Did the community have sufficient access to review any such
normative references?

  All normative references are to RFCs.

17. Are there any normative downward references (see RFC 3967, BCP
97)? If so, list them.

  There are no downward references.

18. Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If they exist, what
is the plan for their completion?

  There are no such reference.

19. Will publication of this document change the status of any
existing RFCs? If so, does the Datatracker metadata correctly reflect
this and are those RFCs listed on the title page, in the abstract, and
discussed in the introduction? If not, explain why and point to the
part of the document where the relationship of this document to these
other RFCs is discussed.

  This document does not change the status of any other RFC but it
  does Update RFC 8967.

20. Describe the document shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of
the document. Confirm that all aspects of the document requiring IANA
assignments are associated with the appropriate reservations in IANA
registries. Confirm that any referenced IANA registries have been
clearly identified. Confirm that each newly created IANA registry
specifies its initial contents, allocations procedures, and a
reasonable name (see RFC 8126).

  This document requires no IANA actions.

21. List any new IANA registries that require Designated Expert Review
for future allocations. Are the instructions to the Designated Expert
clear? Please include suggestions of designated experts, if
appropriate.

  This document creates no IANA registries.