Re: [bfcpbis] Spencer Dawkins' Discuss on draft-ietf-bfcpbis-rfc4582bis-15: (with DISCUSS and COMMENT)

[Spencer Dawkins at IETF <[e-mail]>]

Hi, Charles,

On Thu, Nov 5, 2015 at 5:43 PM, Charles Eckel (eckelcu) <[e-mail]>
wrote:

> For TCP, the use of TLS was not required by RFC 4582. For 4582bis, we do
> not require TLS in order to maintain backward compatibility with RFC 4582.
>

Got it. I'm holding my nose on this one, based on backward compatibility,
and given the degree of difficulty in splicing attack packets into the TCP
sequence numbering space if you're off-path. I'm not thrilled, but someone
else needs to decide when threats reach the level where making that
incompatible change is necessary - and that might not be the right thing to
do today.


> For UDP, the reason for not mandating DTLS is backward compatibility with
> existing solutions. The IMTC Role Based Video Best Practice established a
> set of recommendations for getting BFCP to work  within enterprise video
> conference deployments. As that time,draft-sandbakken-xcon-bfcp-udp defined
> BFCP over UDP only. DTLS was left for future study. Today we have many
> implementations of BFCP over UDP, but few if any using DTLS. We need the
> ultimate RFC that standardizes BFCP over UDP (and over DTLS) to allow
> interworking with these existing deployments.
>

OK, I'm not the Protocol Security Police, so, fine, but it seems like the
draft could be clearer about this, and what you said in your answer would
be really helpful in the document.

If the text said something like "DTLS is REQUIRED unless you are
interworking with a pre-standardization deployment that is already
insecure, in which case you're not making things worse by running without
transport-level security", that would capture my concern and reflect what
you're saying, unless I'm missing something.

Thanks to you and Paul for the speedy response on the evening of Bits and
Bites!

Spencer