Re: [TLS] Comments on draft-rescorla-tls-renegotiate, and a new proposal

Nicolas Williams <Nicolas.Williams@sun.com> Sat, 14 November 2009 08:55 UTC

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Date: Sat, 14 Nov 2009 02:43:58 -0600
From: Nicolas Williams <Nicolas.Williams@sun.com>
To: David-Sarah Hopwood <david-sarah@jacaranda.org>
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Cc: tls@ietf.org
Subject: Re: [TLS] Comments on draft-rescorla-tls-renegotiate, and a new proposal
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On Sat, Nov 14, 2009 at 07:04:19AM +0000, David-Sarah Hopwood wrote:
> Still, that's no worse than the situation with the current
> draft-rescorla-tls-renegotiate. So I think that what I suggested:
> 
> > [...] only use an extension
> > as an advisory of patched status (i.e. say that an empty extension SHOULD
> > be sent if patched), but add the verify_data into the Finished hashes
> > unconditionally (i.e. as a MUST) for renegotiating handshakes. Then, the
> > concerns about extensions potentially breaking some servers, and the
> > concerns about lack of an extension potentially resulting in a security
> > weakness (due to a client being unable to tell whether a server is patched),
> > would only arise in mutually exclusive sets of cases.
> 
> is still an overall improvement.

I think that adding to my proposed fix an _optional_ signal in the
client's hello (and, correspondingly, in the server hello), would be
just fine.  I don't believe it's necessary.

Nico
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