Re: [TLS] Update spec to match current practices for certificate chain order

Peter Gutmann <pgut001@cs.auckland.ac.nz> Thu, 07 May 2015 05:50 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Dave Garrett <davemgarrett@gmail.com>, "tls@ietf.org" <tls@ietf.org>
Thread-Topic: [TLS] Update spec to match current practices for certificate chain order
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Date: Thu, 7 May 2015 05:50:18 +0000
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Subject: Re: [TLS] Update spec to match current practices for certificate chain order
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Dave Garrett <davemgarrett@gmail.com> writes:

>I'd like to propose simply changing that second "MUST" to a "SHOULD" or
>possibly even a "RECOMMENDED", thus allowing for clients to accept cert
>chains in different orderings as they already seem to do. (no change proposed
>for the first "MUST")

I suspect the first MUST can go as well, particularly if you're using code
that handles cert chains in other formats like CMS/PKCS #7, where the "chain"
can contain any old rubbish and the chain-assembly code has to build the path.
For example my code looks for a cert containing the site name 
("www.whatever.com") and then builds a chain up via the parent links until it
can't find any more useful certs.  That just works no matter what the other
side sends.

Peter.