[secdir] secdir review of draft-ietf-tcpm-tcp-timestamps-02

"Scott G. Kelly" <scott@hyperthought.com> Wed, 15 December 2010 18:30 UTC

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Date: Wed, 15 Dec 2010 10:31:45 -0800 (PST)
From: "Scott G. Kelly" <scott@hyperthought.com>
To: "secdir@ietf.org" <secdir@ietf.org>, "iesg@ietf.org" <iesg@ietf.org>, draft-ietf-tcpm-tcp-timestamps.all@tools.ietf.org
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Subject: [secdir] secdir review of draft-ietf-tcpm-tcp-timestamps-02
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I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG.  These comments were written primarily for the benefit of the security area directors.  Document editors and WG chairs should treat these comments just like any other last call comments.

This document describes modified processing steps for SYN segments received for connections in TIME-WAIT state, with the aim being to allow higher connection rates. The security considerations section references a comprehensive discussion of the security implications for TCP timestamps. I see no security issues with this document.

Minor nits:

The last paragraph of section 3 includes this sentence:

   "As noted in [Silbersack], such randomization
   schemes break prevent the mechanism proposed in this document from
   recycling connections that are in the TIME-WAIT state."

Might want to remove the word "break".

The security considerations has this paragraph:

   While the algorithm described in this document for processing
   incoming SYN segments would benefit from TCP timestamps that are
   monotonically-increasing across connections, this document does not
   propose any specific algorithm for generating timestamps, nor does it
   require monotonically-increasing timestamps across connections.

Maybe I'm just naive, but based on the information given, I don't understand why this statement is in the security considerations section. Does the failure to propose any specific algorithms have security consideration (that might be more obvious to someone who reads [CPNI-TCP])?