Re: [TLS] RFC-4366-bis and the unrecognized_name(112) alert

"Joseph Salowey (jsalowey)" <jsalowey@cisco.com> Thu, 03 June 2010 05:23 UTC

Return-Path: <jsalowey@cisco.com>
X-Original-To: tls@core3.amsl.com
Delivered-To: tls@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 8970D3A67C1 for <tls@core3.amsl.com>; Wed, 2 Jun 2010 22:23:14 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.11
X-Spam-Level:
X-Spam-Status: No, score=-9.11 tagged_above=-999 required=5 tests=[BAYES_05=-1.11, RCVD_IN_DNSWL_HI=-8]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id RGul+zwLbmdM for <tls@core3.amsl.com>; Wed, 2 Jun 2010 22:23:10 -0700 (PDT)
Received: from sj-iport-4.cisco.com (sj-iport-4.cisco.com [171.68.10.86]) by core3.amsl.com (Postfix) with ESMTP id F185A3A6A93 for <tls@ietf.org>; Wed, 2 Jun 2010 22:22:51 -0700 (PDT)
Authentication-Results: sj-iport-4.cisco.com; dkim=neutral (message not signed) header.i=none
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: AvsEAE7ZBkyrR7Hu/2dsb2JhbACeJXGlQJoGhRYEg0g
X-IronPort-AV: E=Sophos;i="4.53,351,1272844800"; d="scan'208";a="138562838"
Received: from sj-core-5.cisco.com ([171.71.177.238]) by sj-iport-4.cisco.com with ESMTP; 03 Jun 2010 05:22:34 +0000
Received: from xbh-sjc-221.amer.cisco.com (xbh-sjc-221.cisco.com [128.107.191.63]) by sj-core-5.cisco.com (8.13.8/8.14.3) with ESMTP id o535MXGD001636; Thu, 3 Jun 2010 05:22:33 GMT
Received: from xmb-sjc-225.amer.cisco.com ([128.107.191.38]) by xbh-sjc-221.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.3959); Wed, 2 Jun 2010 22:22:33 -0700
X-MimeOLE: Produced By Microsoft Exchange V6.5
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Date: Wed, 2 Jun 2010 22:22:32 -0700
Message-ID: <AC1CFD94F59A264488DC2BEC3E890DE50A9ED6F5@xmb-sjc-225.amer.cisco.com>
In-Reply-To: <4BFC0FB9.5030908@pobox.com>
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
Thread-Topic: [TLS] RFC-4366-bis and the unrecognized_name(112) alert
Thread-Index: Acr8M+Y7aPzYoYH6RK6fTJpjkyEosQGqK93Q
References: <201005251657.o4PGvZkE006346@fs4113.wdf.sap.corp> <4BFC0FB9.5030908@pobox.com>
From: "Joseph Salowey (jsalowey)" <jsalowey@cisco.com>
To: "Michael D'Errico" <mike-list@pobox.com>, <mrex@sap.com>
X-OriginalArrivalTime: 03 Jun 2010 05:22:33.0863 (UTC) FILETIME=[C56EE170:01CB02DC]
Cc: tls@ietf.org
Subject: Re: [TLS] RFC-4366-bis and the unrecognized_name(112) alert
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <tls.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/tls>, <mailto:tls-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/tls>
List-Post: <mailto:tls@ietf.org>
List-Help: <mailto:tls-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tls>, <mailto:tls-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 03 Jun 2010 05:23:15 -0000

It seems that the behavior is dependent upon the application.  I'm not
sure we would come up with useful text here.  In the interest of getting
this document published I suggest we leave it as is.  

Joe

> -----Original Message-----
> From: tls-bounces@ietf.org [mailto:tls-bounces@ietf.org] On Behalf Of
> Michael D'Errico
> Sent: Tuesday, May 25, 2010 10:58 AM
> To: mrex@sap.com
> Cc: tls@ietf.org
> Subject: Re: [TLS] RFC-4366-bis and the unrecognized_name(112) alert
> 
> Martin Rex wrote:
> > Michael D'Errico wrote:
> >> In my server code, the SNI is checked to see if there is a matching
> >> virtual host with that domain name.  If there is, then no alert is
> >> sent.  If there is no matching virtual host, then it checks whether
> >> there is a default virtual host set up.  If there is a default,
then
> >> an unrecognized_name alert is sent with the warning level.  When no
> >> default is configured, the alert sent is fatal since the handshake
> >> can not continue.
> >>
> >> The warning lets the client know that there was not a match, but
> that
> >> the server can still continue using its default.
> >
> >
> > While this behaviour appears quite sensible/plausible, it will lead
> > to the behaviour in the wild that Yngve is reporting.
> >
> > An application which
> > does not configure any SNI characteristics, is not using SNI, and
> > for these, the server TLS implementation should _NOT_ be sending
> > SNI mismatch TLS alerts unless the application explicitly requests
> so.
> 
> My server code will not send an alert unless the client (a) sent an
> SNI and (b) that SNI did not map to a virtual host.
> 
> So that should not cause a problem.
> 
> It might be a good idea to clarify when sending an unrecognized_name
> alert would be appropriate and clarify that it can be just a warning
> and what that means.
> 
> Mike
> _______________________________________________
> TLS mailing list
> TLS@ietf.org
> https://www.ietf.org/mailman/listinfo/tls