IETF Logo Mail Archive

Re: [TLS] No cypher overlap

Simon Josefsson <simon@josefsson.org> Mon, 03 August 2015 19:13 UTC

Return-Path: <simon@josefsson.org>
X-Original-To: tls@ietfa.amsl.com
Delivered-To: tls@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 19A551ACD0C for <tls@ietfa.amsl.com>; Mon, 3 Aug 2015 12:13:26 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.551
X-Spam-Level:
X-Spam-Status: No, score=-1.551 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HELO_EQ_SE=0.35, SPF_PASS=-0.001] autolearn=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id t6D_QWthDwCQ for <tls@ietfa.amsl.com>; Mon, 3 Aug 2015 12:13:25 -0700 (PDT)
Received: from duva.sjd.se (duva.sjd.se [IPv6:2001:9b0:1:1702::100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id E05901ACD01 for <tls@ietf.org>; Mon, 3 Aug 2015 12:13:24 -0700 (PDT)
Received: from latte.josefsson.org (host-78-65-208-9.homerun.telia.com [78.65.208.9]) (authenticated bits=0) by duva.sjd.se (8.14.4/8.14.4/Debian-4) with ESMTP id t73JDAFi014934 (version=TLSv1/SSLv3 cipher=AES128-GCM-SHA256 bits=128 verify=NOT); Mon, 3 Aug 2015 21:13:12 +0200
From: Simon Josefsson <simon@josefsson.org>
To: Hubert Kario <hkario@redhat.com>
References: <8087760.Ce9A43SzlW@pintsize.usersys.redhat.com> <2289724.pXJjcWpFTc@pintsize.usersys.redhat.com> <871tfm1zgl.fsf@mid.deneb.enyo.de> <2591292.9iByWAuqya@pintsize.usersys.redhat.com>
OpenPGP: id=54265E8C; url=http://josefsson.org/54265e8c.txt
X-Hashcash: 1:22:150803:hkario@redhat.com::mnYv2//llt2a8YRs:EogG
X-Hashcash: 1:22:150803:tls@ietf.org::tHHklkFfsgUwoCrQ:B+mw
X-Hashcash: 1:22:150803:fw@deneb.enyo.de::CObVuu2aDI4DdAKy:HV70
Date: Mon, 03 Aug 2015 21:13:09 +0200
In-Reply-To: <2591292.9iByWAuqya@pintsize.usersys.redhat.com> (Hubert Kario's message of "Mon, 03 Aug 2015 13:36:22 +0200")
Message-ID: <87io8w6v96.fsf@latte.josefsson.org>
User-Agent: Gnus/5.130014 (Ma Gnus v0.14) Emacs/24.4 (gnu/linux)
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-="; micalg="pgp-sha256"; protocol="application/pgp-signature"
X-Virus-Scanned: clamav-milter 0.98.7 at duva.sjd.se
X-Virus-Status: Clean
Archived-At: <http://mailarchive.ietf.org/arch/msg/tls/9KqvxJMNEIsyPKxvBaRmuyrUyGs>
Cc: Florian Weimer <fw@deneb.enyo.de>, tls@ietf.org
Subject: Re: [TLS] No cypher overlap
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.15
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/options/tls>, <mailto:tls-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/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, 03 Aug 2015 19:13:26 -0000

Hubert Kario <hkario@redhat.com> writes:

> On Saturday 01 August 2015 23:16:42 Florian Weimer wrote:
>> * Hubert Kario:
>> > On Tuesday 28 July 2015 16:01:55 Viktor Dukhovni wrote:
>> >> In that case, it should be said that a client MUST NOT advertise
>> >> TLS 1.3 unless it offers at least one of the TLS 1.3 MTI ciphers
>> >> (or perhaps less restrictive at least one TLS 1.3 compatible cipher).
>> > 
>> > MTI does not mean Mandatory To Enable
>> 
>> Are you sure?  That's extremely surprising.
>
> yes, I'm sure:
>
> per https://tools.ietf.org/html/rfc5246#page-65
>
>>9.  Mandatory Cipher Suites
>>
>>   In the absence of an application profile standard specifying
>>   otherwise, a TLS-compliant application MUST implement the cipher
>>   suite TLS_RSA_WITH_AES_128_CBC_SHA (see Appendix A.5 for the
>>   definition).

I don't read anything about enable in deployments here?  Having code
implementing something does not prevent configuration (and even default
settings) to disable something.

/Simon

v2.23.0 | Report a Bug | By Email