[TLS] Review of PR #209

Martin Thomson <martin.thomson@gmail.com> Sat, 25 July 2015 14:59 UTC

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Date: Sat, 25 Jul 2015 16:59:54 +0200
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From: Martin Thomson <martin.thomson@gmail.com>
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Subject: [TLS] Review of PR #209
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Andrei proposes two changes in https://github.com/tlswg/tls13-spec/pull/209

The first expands the ways in which a server can identify
certificates.  This is fine.  I do wonder whether we can remove
CertificateType entirely for TLS 1.3 though (that can be done
separately).

The second is worrisome.  I don't like that a handshake message now
has two different potential locations that it might appear in.  That
seems like a hazard.  I think that we need a new content type for a
new message that can be used after the handshake completes.  Then
there are two options:
 a) remove CertificateRequest from the handshake entirely and allow
the handshake to complete before authenticating (this has a number of
hazards that make it probably worse than the duplication it addresses)
 b) use CertificateRequest within the handshake, and the new content
type outside of it