[secdir] Secdir early review of draft-ietf-babel-hmac-00

Robert Sparks <rjsparks@nostrum.com> Thu, 01 November 2018 21:59 UTC

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From: Robert Sparks <rjsparks@nostrum.com>
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Date: Thu, 01 Nov 2018 14:59:58 -0700
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Subject: [secdir] Secdir early review of draft-ietf-babel-hmac-00
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Reviewer: Robert Sparks
Review result: Has Issues

This is an early secdir review of draft-ietf-babel-hmac-00

Summary: There are issues in the draft to address


The pseudo-header is IPv4-centric.

The protocol allows for multiple HMAC algorithms, but has no mechanism for
signaling which one was used. The MUST NOT at the top of page 8 will need to
be adjusted after that's worked out.  Discussion of what to do at a verifying
peer that doesn't implement a chosen algorithm is also needed.


The claim in 1.1 about not requiring persistent storage is contradicted by the
definition of the protocol. At the very least, there is the need to persist the
most recent (index,PC) seen.

The third bullet at the top of page 4 (among different nodes) has its actors
confused. As stated, communication between A and C is irrelevant to the
communication between B and C.

It would be worth building an example of bootstrapping the protocol between 
two peers that have no previous knowledge of each other.

It's concerning to see a document (even a 00) whose point is to secure a
protocol have no discussion at all in the Security Considerations section. It
will help refine the document to create and maintain a summary of the important
security points in this section going forward.