Re: [TLS] Summarizing identity change discussion so far

Michael Gray <mickgray@au1.ibm.com> Thu, 17 December 2009 22:16 UTC

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In-Reply-To: <6b9359640912171337j7ed5be63gf431e0fb12070944@mail.gmail.com>
To: Kyle Hamilton <aerowolf@gmail.com>
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From: Michael Gray <mickgray@au1.ibm.com>
Date: Fri, 18 Dec 2009 08:16:29 +1000
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Cc: tls@ietf.org
Subject: Re: [TLS] Summarizing identity change discussion so far
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Kyle Hamilton <aerowolf@gmail.com> wrote:

> On Tue, Dec 8, 2009 at 1:13 AM,  <Pasi.Eronen@nokia.com> wrote:
> > (wearing Area Director hat)
> >
> > - We recommend that TLS libraries SHOULD provide identity matching
> > (with memcmp, abort handshake if changed) functionality to
> > applications, and SHOULD allow applications to enable/disable this
> > functionality.
>
> No, identity matching SHOULD be done in accordance with PKIX.  memcmp
> is not at all sufficient.
>
> However, I would support the following:
>
> - TLS libraries SHOULD provide identity matching services between and
> throughout renegotiation handshakes.  Libraries SHOULD implement this
> in accordance with PKIX [PKIX], but MAY do so with a direct memory
> comparison.  Implementors are cautioned that this latter approach does
> not provide for changing the cipher parameters -- such as a
> renegotiation with an EC or DH certificate after identification with
> an RSA certificate.  If the identity matching service fails to match
> the identity, implementations MUST abort the handshake with a fatal
> bad_certificate alert.

I am also in favour of this wording or wording to that effect.

- Mick

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