Re: [Curdle] draft-ssorce-gss-keyex-sha2-00

Simo Sorce <simo@redhat.com> Fri, 21 April 2017 12:48 UTC

Return-Path: <simo@redhat.com>
X-Original-To: curdle@ietfa.amsl.com
Delivered-To: curdle@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 3610A129432 for <curdle@ietfa.amsl.com>; Fri, 21 Apr 2017 05:48:08 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.922
X-Spam-Level:
X-Spam-Status: No, score=-6.922 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RP_MATCHES_RCVD=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=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 3abbvaP9SVHj for <curdle@ietfa.amsl.com>; Fri, 21 Apr 2017 05:48:06 -0700 (PDT)
Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id AC2EC124234 for <curdle@ietf.org>; Fri, 21 Apr 2017 05:48:06 -0700 (PDT)
Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2D8F2691BD; Fri, 21 Apr 2017 12:48:06 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 2D8F2691BD
Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com
Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=simo@redhat.com
DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 2D8F2691BD
Received: from ovpn-116-177.phx2.redhat.com (ovpn-116-177.phx2.redhat.com [10.3.116.177]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 79B0789F6C; Fri, 21 Apr 2017 12:48:03 +0000 (UTC)
Message-ID: <1492778882.3662.221.camel@redhat.com>
From: Simo Sorce <simo@redhat.com>
To: "Mark D. Baushke" <mdb@juniper.net>
Cc: Hubert Kario <hkario@redhat.com>, curdle@ietf.org
Date: Fri, 21 Apr 2017 08:48:02 -0400
In-Reply-To: <44543.1492614656@eng-mail01.juniper.net>
References: <39113.1492406108@eng-mail01.juniper.net> <1670339.BpRFGmRBOW@pintsize.usersys.redhat.com> <44543.1492614656@eng-mail01.juniper.net>
Organization: Red Hat, Inc.
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 21 Apr 2017 12:48:06 +0000 (UTC)
Archived-At: <https://mailarchive.ietf.org/arch/msg/curdle/7f67O1MG74Ek984maOkPO5LkXxk>
Subject: Re: [Curdle] draft-ssorce-gss-keyex-sha2-00
X-BeenThere: curdle@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: "List for discussion of potential new security area wg." <curdle.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/curdle>, <mailto:curdle-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/curdle/>
List-Post: <mailto:curdle@ietf.org>
List-Help: <mailto:curdle-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/curdle>, <mailto:curdle-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 21 Apr 2017 12:48:08 -0000

On Wed, 2017-04-19 at 08:10 -0700, Mark D. Baushke wrote:
> Hubert Kario <hkario@redhat.com> writes:
> 
> > On Monday, 17 April 2017 07:15:08 CEST Mark D. Baushke wrote:
> > > Hi Simo & Hubert,
> > > 
> > > Regarding your draft:
> > > https://www.ietf.org/id/draft-ssorce-gss-keyex-sha2-00.txt
> > > 
> > > The reference to the -05 I-D.ietf-curdle-ssh-kex-sha2 should probably be
> > > replaced with a reference to draft-ietf-curdle-ssh-modp-dh-sha2-04
> > 
> > It probably should have references to both.
> 
> The ietf-curdle-ssh-kex-sha2-08 is referencing your draft right now. I
> am not sure a circular dependency is needed.
> 
> > > I am somewhat curious why the same curves identified in RFC5656 as
> > > nistp256, nistp384, and nistp521 are being called secp256r1, secp384r1,
> > > secp521r1 in your draft in section 6. Is there a good reason to select
> > > this form of the names?
> > 
> > Because I took those names from TLS curve registry. Making them consistent 
> > with other SSH names is a good idea though. Thanks!
> > 
> > > I will note that gss-secp384r1-sha512-* should probably be
> > > gss-secp384r1-sha384-* to be consistent with how RFC5656
> > > felt security should be handled.
> > 
> > Good point.
> > 
> > > I do know that there is some controversy about supporting SHA2-384
> > > rather than SHA2-256 and SHA2-512, but it has been argued that SHA2-384
> > > does not expose as much of its internal state as does SH2-512 and that
> 
> oops s/SH2/SHA2/
> 
> > > it aligns more closely with the nistp384 curve.
> > 
> > how is that applicable to the KEX?
> 
> I am not sure it is, but it was originally argued that ECDH and ECDSA
> should use the same hashing mechanisms. So, if ECDSA mandates SHA2-384
> for a nistp384 curve, then using the same thing in ECDSA seems less
> likely to cause confusion.
> 
> I only mentioned the SHA2-384 vs SHA2-512 issue if you wanted to add it
> to your security considerations section. I regret that I was not clear
> in my comment.
> 
> I hope my comments have made sense.

Thank you Mark,
sorry for not commenting, I was on vacation, I will take on your changes
and release a new draft asap.

Simo.

-- 
Simo Sorce
Sr. Principal Software Engineer
Red Hat, Inc