Re: [TLS] drop obsolete SSL 2 backwards compatibility from TLS 1.3 draft

Brian Smith <brian@briansmith.org> Tue, 23 December 2014 21:51 UTC

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Date: Tue, 23 Dec 2014 13:51:40 -0800
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From: Brian Smith <brian@briansmith.org>
To: Dave Garrett <davemgarrett@gmail.com>
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Subject: Re: [TLS] drop obsolete SSL 2 backwards compatibility from TLS 1.3 draft
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Dave Garrett <davemgarrett@gmail.com>; wrote:
> The PR replaces the section with a simple "MUST NOT" send or accept for TLS 1.3
> implementations.

It would be best to have your change do exactly that, by shortening
the remaining text to:

    Implementations MUST NOT send or accept an SSL
    version 2.0 compatible CLIENT-HELLO. Implementations
    MUST NOT send or accept TLS records with a version
    less than { 3, 0 }.

Note the suggestion to use the term "records" instead of "messages".

I think further changes can be made to tighten up the text regarding
allowed record versions, but those changes are more open for debate.
For example, we might say that the ClientHello's record version MUST
be { 3, 1 } and that the version field in all other records MUST equal
the negotiated version. But, again, this can be done on top of your
changes.

Cheers,
Brian