Subject: [babel] feedback this Friday

From: Denis Ovsienko <[email-masked]>
Date: Tue, 15 Nov 2016 23:23:30 +0000

Hello list(s).

This coming Friday meeting of the Babel WG includes my slides and I plan to present remotely. My concern is two issues: one is how bidirectional neighbour detection controls the rest of the protocol operation and another is how the bidirectional detection itself can be made more secure considering a particular form of replay attack. It seems to me both issues are important enough to discuss and to decide how to action, this mostly concerns RFC 6126-bis but may also have something to do with RFC 7298.

The slides are in the meeting materials: https://datatracker.ietf.org/meeting/97/materials/#rtg

It would be great if on one of the remaining days before the meeting you could look through the slides and the (quite short) sections in RFC 6126 referred from one of the first slides. Your feedback and questions will be welcome at the meeting and on the babel@ietf mailing list.

Thank you.

-- 
    Denis Ovsienko

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From: Juliusz Chroboczek <[email-masked]>
Date: Wed, 16 Nov 2016 07:42:27 +0100

Hi Denis,

The Babel neighbour sensing mechanism is exactly as you describe: if
a given IP address hasn't sent you a Hello, it doesn't exist, and all
packets from it are silently dropped until it sends a Hello.  This is by
design.

You are correct that an IHU does not carry explicit information about
individual hellos, but just a single integer that summarises the link
quality.  That's by design, and that's the reason why IHU is called IHU,
not Ack.

I haven't been able to understand the attack that you outline just from
looking at the slides, so I suggest we discuss it after you've done your
presentation.

-- Juliusz