Re: [secdir] Secdir review of draft-ietf-mipshop-rfc5268bis-01

Vijay Devarapalli <vijay@wichorus.com> Tue, 28 April 2009 15:49 UTC

Return-Path: <vijay@wichorus.com>
X-Original-To: secdir@core3.amsl.com
Delivered-To: secdir@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id A7E6428C279; Tue, 28 Apr 2009 08:49:21 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.827
X-Spam-Level:
X-Spam-Status: No, score=-0.827 tagged_above=-999 required=5 tests=[AWL=-0.295, BAYES_00=-2.599, RCVD_NUMERIC_HELO=2.067]
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 4ZcckeJoW52V; Tue, 28 Apr 2009 08:49:17 -0700 (PDT)
Received: from outbound.mse15.exchange.ms (outbound.mse15.exchange.ms [216.52.164.185]) by core3.amsl.com (Postfix) with ESMTP id 3165228C275; Tue, 28 Apr 2009 08:49:17 -0700 (PDT)
Received: from 67.161.28.136 ([67.161.28.136]) by mse15be2.mse15.exchange.ms ([172.30.10.130]) via Exchange Front-End Server owa.mse15.exchange.ms ([172.30.10.124]) with Microsoft Exchange Server HTTP-DAV ; Tue, 28 Apr 2009 15:50:35 +0000
User-Agent: Microsoft-Entourage/12.10.0.080409
Date: Tue, 28 Apr 2009 08:50:34 -0700
From: Vijay Devarapalli <vijay@wichorus.com>
To: Yaron Sheffer <yaronf@checkpoint.com>
Message-ID: <C61C73DA.6B23%vijay@wichorus.com>
Thread-Topic: Secdir review of draft-ietf-mipshop-rfc5268bis-01
Thread-Index: AcnHfX4isqIXn9i3RIOQd2HVTiilfwAVYcKAABGC7qw=
In-Reply-To: <7F9A6D26EB51614FBF9F81C0DA4CFEC8D9ACEC55D6@il-ex01.ad.checkpoint.com>
Mime-version: 1.0
Content-type: text/plain; charset="US-ASCII"
Content-transfer-encoding: 7bit
Cc: "draft-ietf-mipshop-rfc5268bis@tools.ietf.org" <draft-ietf-mipshop-rfc5268bis@tools.ietf.org>, "iesg@ietf.org" <iesg@ietf.org>, "secdir@ietf.org" <secdir@ietf.org>
Subject: Re: [secdir] Secdir review of draft-ietf-mipshop-rfc5268bis-01
X-BeenThere: secdir@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: Security Area Directorate <secdir.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/secdir>, <mailto:secdir-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/secdir>
List-Post: <mailto:secdir@ietf.org>
List-Help: <mailto:secdir-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/secdir>, <mailto:secdir-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 28 Apr 2009 15:49:21 -0000

Hi Yaron,

On 4/28/09 12:42 AM, "Yaron Sheffer" wrote:

> Hi Vijay,
> 
> Actually you are proving my point :-)

No it doesn't.

> The cost of setting up a security
> association (e.g. an IKE exchange) will be amortized over many HI/HACK uses.

The cost of implementing and configuring a key negotiation protocol is not
worth it when we are looking at just one IPsec SA for all FMIPv6 related
signaling between the access routers. So I don't think having some text that
says "a key negotiation protocols is RECOMMENDED" is justified.

If deployments don't want to deal with manual IPsec keying (because it is a
hassle), they will start using IKEv2 automatically.
 
> And automatic key management is a BCP for some very good reasons, including:
> - Limiting the lifetime of keys.
> - Facilitating algorithm agility.
> - Enabling the use of shorter shared secrets and/or certificates.
> - Mitigating the harmful effect of using "widely shared" secrets (where all
> group members see the same shared secret).
> - Improving the entropy of encryption keys compared to human generated
> "random" values.
> 
> I'm sure there are a few other reasons I've forgotten.

Almost all of these are not a concern when we talk about access routers in
an FMIPv6 domain, IMO.

Vijay

> 
> Thanks,
> Yaron
> 
>> -----Original Message-----
>> From: Vijay Devarapalli [mailto:vijay@wichorus.com]
>> Sent: Tuesday, April 28, 2009 0:17
>> To: Yaron Sheffer
>> Cc: secdir@ietf.org; iesg@ietf.org; draft-ietf-mipshop-
>> rfc5268bis@tools.ietf.org
>> Subject: Re: Secdir review of draft-ietf-mipshop-rfc5268bis-01
>> 
>> Hi Yaron,
>> 
>> Yaron Sheffer wrote:
>>> I have reviewed this document as part of the security directorate's
>> ongoing
>>> effort to review all IETF documents being processed by the IESG.  These
>>> comments were written primarily for the benefit of the security area
>>> directors.  Document editors and WG chairs should treat these comments
>> just
>>> like any other last call comments.
>>> 
>>> This document updates RFC 5268 (itself quite recent) by changing some
>> ICMP
>>> messages into more modern mobility header-carrying messages. I don't
>> believe
>>> this has any security implications. In fact the document includes very
>>> thorough Security Considerations, inherited from RFC 5268 and slightly
>>> adapted for the new message formats.
>>> 
>>> One issue that came up before the original RFC was published is the
>>> protocol's liberality regarding (1) manual keying vs. key management
>>> protocols, and (2) the choice of authentication method. The second issue
>> was
>>> rectified by adding the text: "If IKEv2 is used [...] to ensure a
>> baseline
>>> interoperability, the implementations MUST support shared secrets for
>> mutual
>>> authentication." But this leaves the first issue open: manual keying
>> remains
>>> an option. So I propose to add to:
>>> 
>>> "The security associations can be created by using either manual IPsec
>>> configuration or a dynamic key negotiation protocol such as IKEv2
>>> [rfc4306]."
>>> 
>>> This new text:
>>> 
>>> "Following the recommendations of RFC 5406 (Sec. 3.3), the use of a key
>>> negotiation protocol is RECOMMENDED."
>> 
>> I don't see this as being applicable to security associations setup
>> between two access routers in the same domain. Note that the access
>> routers need just one security association for protecting the HI and
>> HACK messages for all the mobile nodes. Recommending the use of a key
>> negotiation protocol in this case would be over specification, IMO.
>> 
>> Vijay
>> 
>> Scanned by Check Point Total Security Gateway.