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

Marsh Ray <marsh@extendedsubset.com> Mon, 07 June 2010 17:55 UTC

Return-Path: <marsh@extendedsubset.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 964393A67A7 for <tls@core3.amsl.com>; Mon, 7 Jun 2010 10:55:05 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.185
X-Spam-Level:
X-Spam-Status: No, score=-0.185 tagged_above=-999 required=5 tests=[BAYES_40=-0.185]
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 MhCo69SCm-9l for <tls@core3.amsl.com>; Mon, 7 Jun 2010 10:55:04 -0700 (PDT)
Received: from mho-01-ewr.mailhop.org (mho-01-ewr.mailhop.org [204.13.248.71]) by core3.amsl.com (Postfix) with ESMTP id B0C333A6989 for <tls@ietf.org>; Mon, 7 Jun 2010 10:51:52 -0700 (PDT)
Received: from xs01.extendedsubset.com ([69.164.193.58]) by mho-01-ewr.mailhop.org with esmtpa (Exim 4.68) (envelope-from <marsh@extendedsubset.com>) id 1OLgUK-000CqD-WC; Mon, 07 Jun 2010 17:51:53 +0000
Received: from [127.0.0.1] (localhost [127.0.0.1]) by xs01.extendedsubset.com (Postfix) with ESMTP id 6321C64D9; Mon, 7 Jun 2010 17:51:49 +0000 (UTC)
X-Mail-Handler: MailHop Outbound by DynDNS
X-Originating-IP: 69.164.193.58
X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/mailhop/outbound_abuse.html for abuse reporting information)
X-MHO-User: U2FsdGVkX1/Y2gvcyVz9fHLDNe4/BHl2AnbApRKjmcg=
Message-ID: <4C0D31B4.4010301@extendedsubset.com>
Date: Mon, 07 Jun 2010 12:51:48 -0500
From: Marsh Ray <marsh@extendedsubset.com>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.8) Gecko/20100216 Thunderbird/3.0.2
MIME-Version: 1.0
To: mrex@sap.com
References: <201006071446.o57EkTuW029119@fs4113.wdf.sap.corp>
In-Reply-To: <201006071446.o57EkTuW029119@fs4113.wdf.sap.corp>
X-Enigmail-Version: 1.0.1
OpenPGP: id=1E36DBF2
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
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: Mon, 07 Jun 2010 17:55:05 -0000

On 6/7/2010 9:46 AM, Martin Rex wrote:
> 
> I actually fail to see the exact purpose of a warning-level alert
> "unrecognized_name".  The client is supposed to perform the server endpoint
> identification in any case,

Let us not forget anon-anon connections!

Even for authenticated-server connections, some authentications are
stronger or more specific than others. This can be affected by SNI.

> and that warning should not affect the
> outcome of that process at all.

For example, an SNI-aware client app may request webservice.example.com,
but a DNS mixup sends him to the SNI-aware server serving
www.example.com with a wildcard certificate valid for *.example.com.

In this case I think a failed handshake would be the best outcome.

- Marsh