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Re: [TLS] some questions for your draft

Marsh Ray <marsh@extendedsubset.com> Thu, 26 November 2009 20:53 UTC

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Date: Thu, 26 Nov 2009 14:53:48 -0600
From: Marsh Ray <marsh@extendedsubset.com>
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Cc: tls@ietf.org
Subject: Re: [TLS] some questions for your draft
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Martin Rex wrote:
> Marsh Ray wrote:
> 
>> And I have yet to see any developer-oriented documentation provide
>> example code that does everything right.
> 
> It's worse than that.  There has been no possible way for
> a TLS implementation to get this right!

In the liberal spec-interpretation general case, yes.

> When would be the correct time to fire such a callback?

1. Many applications could run with a default of disabling renegotiation
entirely. You could possibly live without a callback in many of those cases.

2. The implementation could refuse data between hello and finished and
provide callbacks on cert verify and finished.

3. Otherwise, a callback on just about every handshake message would be
needed, and the subtleties of application data, alerts, and handshake
messages would all be pushed off onto the application.

> Try to describe it in terms of before/while/after which Handshake
> message any why.

1. Disable all renegotiation.
or
2. Consult your application-level protocol documentation which will
perfectly spell out the allowed sequence of TLS messages. :-)

- Marsh

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