Re: [TLS] RI, TLS Extension tolerance and version tolerance in

David-Sarah Hopwood <david-sarah@jacaranda.org> Tue, 15 December 2009 03:28 UTC

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Date: Tue, 15 Dec 2009 03:28:41 +0000
From: David-Sarah Hopwood <david-sarah@jacaranda.org>
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Subject: Re: [TLS] RI, TLS Extension tolerance and version tolerance in
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Yngve Nysaeter Pettersen wrote:
> If the server does not support renegotiation then it might not support
> the extension, but my proposal is that it MUST be TLS Extension
> *tolerant*. I am however suggestion, optionally, that supporting the
> extension should be a MUST in patched servers.

It has to be a MUST. Otherwise,
 - strict clients will unnecessarily abort the handshake when they
   don't see the extension.
 - lenient clients won't know to reconnect, so rollback attacks are
   not necessarily prevented.

-- 
David-Sarah Hopwood  ⚥  http://davidsarah.livejournal.com