Re: [TLS] AD Review of draft-ietf-tls-tls13

Viktor Dukhovni <ietf-dane@dukhovni.org> Mon, 15 May 2017 20:21 UTC

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From: Viktor Dukhovni <ietf-dane@dukhovni.org>
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Date: Mon, 15 May 2017 16:19:07 -0400
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Subject: Re: [TLS] AD Review of draft-ietf-tls-tls13
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> On May 15, 2017, at 3:38 PM, Russ Housley <housley@vigilsec.com> wrote:
> 
>>> I don't see an explanation of why it is out-of-scope.  The reference
>>> is just to RFC5280, which seems odd.  I would expect the reference to
>>> be to something that explains why it is out-of-scope.
> 
> I think the the separation of certificate path validation from the TLS
> protocol is correct, but perhaps this can be explained differently.
> Perhaps the approach should be that TLS depends upon certificate path
> validation as described in RFC 5280.

That's not always true.  With DANE-EE(3) TLSA records there is no
path validation.  You just validate the EE certificate directly.

With DANE-EE(2), there's an RFC5280 chain, but it terminates on
a trust-anchor provided by the peer as part of its chain, with
a hash in DNS.

With unauthenticated opportunistic TLS, the peer's chain is ignored
entirely.

How and whether the peer's certificate message is used is properly
outside TLS.

-- 
	Viktor.