Re: [OSPF] AD review of draft-ietf-ospf-security-extension-manual-keying-08

"Acee Lindem (acee)" <acee@cisco.com> Fri, 03 October 2014 20:34 UTC

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From: "Acee Lindem (acee)" <acee@cisco.com>
To: Alia Atlas <akatlas@gmail.com>, Ospf Chairs <ospf-chairs@tools.ietf.org>, "draft-ietf-ospf-security-extension-manual-keying@tools.ietf.org" <draft-ietf-ospf-security-extension-manual-keying@tools.ietf.org>, "Vishwas Manral" <vishwas.ietf@gmail.com>, OSPF List <ospf@ietf.org>
Thread-Topic: [OSPF] AD review of draft-ietf-ospf-security-extension-manual-keying-08
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Date: Fri, 3 Oct 2014 20:34:05 +0000
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Subject: Re: [OSPF] AD review of draft-ietf-ospf-security-extension-manual-keying-08
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Hi Alia,
Thanks for the review. See inline.

From: Alia Atlas <akatlas@gmail.com<mailto:akatlas@gmail.com>>
Date: Friday, October 3, 2014 at 3:52 PM
To: Ospf Chairs <ospf-chairs@tools.ietf.org<mailto:ospf-chairs@tools.ietf.org>>, "draft-ietf-ospf-security-extension-manual-keying@tools.ietf.org<mailto:draft-ietf-ospf-security-extension-manual-keying@tools.ietf.org>" <draft-ietf-ospf-security-extension-manual-keying@tools.ietf.org<mailto:draft-ietf-ospf-security-extension-manual-keying@tools.ietf.org>>, Vishwas Manral <vishwas.ietf@gmail.com<mailto:vishwas.ietf@gmail.com>>, OSPF WG List <ospf@ietf.org<mailto:ospf@ietf.org>>
Subject: [OSPF] AD review of draft-ietf-ospf-security-extension-manual-keying-08

As I do with all drafts that are ready to progress, I have done my AD review of this
draft-ietf-ospf-security-extension-manual-keying-08.  In this case, I apologize for it taking so long.

The draft is very clear and well-written.  I do have a few comments, but I have sent it to IETF Last Call for review while we discuss.  Assuming that goes smoothly and comments (including mine below) are taken into account, I expect the draft to go to IESG telechat for Oct 30.

Major Comment:

My one concern is that in Section 3, it says:

"Additionally, the 64-bit sequence number is moved to the first 64-bits following the OSPFv2 packet and is protected by the authentication digest."

but I do not see any other place where RFC 5709 is updated to include that sequence number.  In Sec 3.3, RFC 5709 says:


   First-Hash = H(Ko XOR Ipad || (OSPFv2 Packet))


and I think it would be most excellent for this draft to clearly

update that to be (OSPFv2 Packet + Sequence Number).

With this draft, we attempted to avoid Stephen Farrell’s ire by not repeating the authentication algorithm as we have done when apply SHAx-HMAC authentication to each routing protocol. Note that RFC 5709 includes the statement:

  Implementation Notes:

          Note that the First-Hash above includes the Authentication
          Trailer containing the Apad value, as well as the OSPF packet,
          as per RFC 2328, Section D.4.3.

In section 5, we wukk add:

                          The 64-bit sequence number will be included in the First-Hash along with the Authentication
                           Trailer and OSPF packet (Refer to Section 3.3 in RFC 5709).




Minor Comments:


Should the meta-data and header indicate that this updated RFC 5709?  It certainly looks like it.

I don’t feel strongly on this. However, this is a new type of OSPFv2 cryptographic authentication and RFC 5709 authentication will continue to be supported by implementations that support it. So, one could argue that it updates RFC 2328 rather than RFC 5709. The whole issue of when to use the “Updates” would be a good topic for WG chair discussion.

Thanks,
Acee





Thanks for the hard work on a good draft to make routing more secure!


Alia