Re: [TLS] WGLC for draft-ietf-tls-oob-pubkey-03.txt

[Paul Hoffman <[e-mail]>]

On Apr 25, 2012, at 5:35 PM, Joe Salowey wrote:

> This is an announcement of working group last call for draft-ietf-tls-oob-pubkey-03.txt.  Please complete reviews and send comments to the TLS list by Friday May 18, 2012.  


I support this document moving forwards, but it requires some significant changes first.

First, the document needs to say "Updates: 6091" because it very much updates 6091.

More importantly, the client auth text added in the last round was:

3.5.  Client authentication

   Client authentication by the TLS server is supported only through
   authentication of the received client SubjectPublicKeyInfo via an
   out-of-band method

This is both wrong and insufficient.

It is wrong in that the server might also authenticate the client through a future TLSA-type protocol that handles user certificates, and might also authenticate the client through LDAP. The entire sentence can be removed.

It is insufficient because it does not say how the client should respond if RawPublicKey certificates have been selected but the client does not have a raw client certificate.

I believe that an equivalent of the "empty_cert" used in RFC 6091 is needed to be defined here and then used in wording such as:

 Therefore, this section should probably instead say:

3.5.  Client Certificate

   This message is only sent in response to the certificate request
   message.  The client certificate message is sent using the same
   formatting as the server certificate message, and it is also required
   to present a certificate that matches the negotiated certificate
   type.  If RawPublicKey certificates have been selected and no certificate
   is available from the client, then a certificate structure of type
   "empty_cert" that contains an RawPublicKey value MUST be sent.
   The server SHOULD respond with a "handshake_failure" fatal alert if
   client authentication is required.

I hope this helps.

--Paul Hoffman