Re: [secdir] secdir review of draft-ietf-fecframe-dvb-al-fec

"Ali C. Begen (abegen)" <abegen@cisco.com> Thu, 31 December 2009 21:50 UTC

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From: "Ali C. Begen (abegen)" <abegen@cisco.com>
To: <scott@hyperthought.com>, <iesg@ietf.org>, <secdir@ietf.org>, <stockhammer@nomor.de>, <fecframe-chairs@tools.ietf.org>
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Subject: Re: [secdir] secdir review of draft-ietf-fecframe-dvb-al-fec
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Hi Scott,

> -----Original Message-----
> From: scott@hyperthought.com [mailto:scott@hyperthought.com]
> Sent: Thursday, December 31, 2009 2:03 PM
> To: iesg@ietf.org; secdir@ietf.org; Ali C. Begen (abegen); stockhammer@nomor.de; fecframe-
> chairs@tools.ietf.org
> Subject: secdir review of draft-ietf-fecframe-dvb-al-fec
> 
> 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.

Thanks for the review.
 
> This document describes implementation of a forward error correction protocol over RTP
> using already-defined protocol elements. The protocol was originally defined by an ETSI
> group.
> 
> The security considerations section says, "This specification adds no new security
> considerations to the DVB-IPTV AL-FEC protocol", which I take to mean that the authors see
> no way in which the proposed approach changes the security properties of the original ETSI
> specification. Since the protocol doesn't seem to implement any security features, I guess
> this is probably correct. Still, it might be better to add some additional commentary such
> as what is found in the security considerations section of draft-ietf-fecframe-
> interleaved-fec-scheme-07.txt (or, perhaps point to that and the framework doc).

We can do this. I'd probably prefer to do this minor addition after all IESG comments are received.
 
> Lacking much necessary background in this area, I don't feel qualified to fully evaluate
> this document. With that deficiency noted, the only possible red flag I saw is that the
> FEC protocol requires that the SSRC fields of the FEC frames be set to 0, while SRTP
> requires unique SSRC values for security reasons. With my very limited background, I can't
> be sure if there is an important security interaction here or not, but it seems worth
> asking about.

Agree, however, that is one of the issues ETSI/DVB was not able to change due to existing implementations in the field. draft-ietf-fecframe-interleaved-fec-scheme does not have this bug, but the al-fec draft needs to say what the ETSI spec currently requires.

Cheers and happy new year.
-acbegen

 
> --Scott
>