Subject: [xmpp] #42: sending a certificate mandatory during TLS negotiation

From: "xmpp issue tracker" <[email-masked]>
Date: Tue, 22 Jun 2010 00:24:26 -0000

#42: sending a certificate mandatory during TLS negotiation
--------------------------------+-------------------------------------------
 Reporter:  stpeter@…           |       Owner:  stpeter@…         
     Type:  defect              |      Status:  new               
 Priority:  minor               |   Milestone:                    
Component:  3920bis             |     Version:                    
 Severity:  In WG Last Call     |    Keywords:                    
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 Section 5.3.3.1 (which covers rules for TLS negotiation) states:

 > 2.  The receiving entity MUST present a certificate.

 Dave Cridland commented: "(2) eliminates usage of, for example, Anonymous
 DH, which might be acceptable in C2S deployments in conjunction with a
 channel-binding SASL mechanism."

-- 
Ticket URL: <http://trac.tools.ietf.org/wg/xmpp/trac/ticket/42>
xmpp <http://tools.ietf.org/xmpp/>

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From: Peter Saint-Andre <[email-masked]>
Date: Sun, 27 Jun 2010 19:21:06 -0600

> #42: sending a certificate mandatory during TLS negotiation

<voice tone='sarcasm'>

How could I have forgotten such a widespread deployment scenario?

</voice>

How is this?

   2.  The receiving entity SHOULD present a certificate (although this
       is strongly encouraged, it is not mandatory because there are
       certain uncommon deployment scenarios in which certificates are
       not used, such as anonymous Diffie-Hellman key exchange with
       subsequent negotiation of a SASL mechanism that supports channel
       binding and a security layer).

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From: "xmpp issue tracker" <[email-masked]>
Date: Mon, 28 Jun 2010 01:22:09 -0000

#42: sending a certificate mandatory during TLS negotiation
--------------------------------+-------------------------------------------
 Reporter:  stpeter@…           |        Owner:  stpeter@…         
     Type:  defect              |       Status:  closed            
 Priority:  minor               |    Milestone:                    
Component:  3920bis             |      Version:                    
 Severity:  In WG Last Call     |   Resolution:  fixed             
 Keywords:                      |  
--------------------------------+-------------------------------------------
Changes (by stpeter@…):

  * status:  new => closed
  * resolution:  => fixed

Comment:

 Provisionally resolved with this text:

-- 
Ticket URL: <http://trac.tools.ietf.org/wg/xmpp/trac/ticket/42#comment:1>
xmpp <http://tools.ietf.org/xmpp/>

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From: Dave Cridland <[email-masked]>
Date: Mon, 28 Jun 2010 11:22:48 +0100

> > #42: sending a certificate mandatory during TLS negotiation
Sarcasm from an American? I shall print it out and frame it and put  
it on my wall.

>        binding and a security layer).
Well, with the MTI suites, this will happen as a result of following  
those suites, so perhaps:

	<t>With all the Mandatory To Implement cipher suites specified in  
Section 0.0.0, the receiving entity presents a certificate.</t>

I don't think there's a need to draw attention to anonymous DH, or go  
off into the weeds concerning how one might make use of it, but  
equally we don't want to mandate certificates in the case where  
they're not required. I'd note that the use of PGP keys in TLS also  
doesn't use certificates, as such.

Dave.
-- 
Dave Cridland - mailto:[email-masked] - xmpp:[email-masked]
  - acap://acap.dave.cridland.net/byowner/user/dwd/bookmarks/
  - http://dave.cridland.net/
Infotrope Polymer - ACAP, IMAP, ESMTP, and Lemonade

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From: Peter Saint-Andre <[email-masked]>
Date: Mon, 28 Jun 2010 08:25:28 -0600

>> > #42: sending a certificate mandatory during TLS negotiation

<snip/>

> Section 0.0.0, the receiving entity presents a certificate.</t>

That's better, thanks.

> off into the weeds concerning how one might make use of it, but equally
> we don't want to mandate certificates in the case where they're not
> required. I'd note that the use of PGP keys in TLS also doesn't use
> certificates, as such.

True.

Peter

-- 
Peter Saint-Andre
https://stpeter.im/