Re: [secdir] SecDir review of draft-ietf-ospf-ospfv3-autoconfig

"Adam W. Montville" <adam.w.montville@gmail.com> Wed, 14 January 2015 17:35 UTC

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From: "Adam W. Montville" <adam.w.montville@gmail.com>
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Date: Wed, 14 Jan 2015 11:35:12 -0600
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References: <47E19730-5BE8-4CC1-9DB3-A341465A5BDB@gmail.com> <D0DB2787.B8DE%acee@cisco.com> <D0DB3988.B91C%acee@cisco.com> <E6065BA2-29AD-4B7A-A444-F50A37B19B35@piuha.net>
To: Jari Arkko <jari.arkko@piuha.net>
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Cc: "draft-ietf-ospf-ospfv3-autoconfig.all@tools.ietf.org" <draft-ietf-ospf-ospfv3-autoconfig.all@tools.ietf.org>, "Acee Lindem \(acee\)" <acee@cisco.com>, The IESG <iesg@ietf.org>, "secdir@ietf.org" <secdir@ietf.org>
Subject: Re: [secdir] SecDir review of draft-ietf-ospf-ospfv3-autoconfig
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Glad to be of service.  It all looks good to me.

> On Jan 14, 2015, at 5:08 AM, Jari Arkko <jari.arkko@piuha.net>; wrote:
> 
> Adam,
> 
> Many thanks for your review. I agree with Acee’s suggested edits.
> 
> Jari
> 
> On 14 Jan 2015, at 04:07, Acee Lindem (acee) <acee@cisco.com>; wrote:
> 
>> Hi Adam, 
>> Here are the updates I’m proposing to address your comments:
>> 
>> *** 180,185 ****
>> --- 180,188 ----
>>    Thanks to Martin Vigoureux for Routing Area Directorate review and
>>    comments.
>> 
>> +    Thanks to Adam Montville for Security Area Directorate review and
>> +    comments.
>> +
>>    Special thanks go to Markus Stenberg for his implementation of this
>>    specification in Bird.
>> 
>> ***************
>> 
>> *** 451,464 ****
>> 
>> 5.  OSPFv3 Router ID Selection
>> 
>> !    An OSPFv3 router requires a unique Router ID for correct protocol
>> !    operation.  An OSPFv3 router implementing this specification will
>> !    select a router-id that has a high probability of uniqueness.  A
>> !    pseudo-random number SHOULD be used for the OSPFv3 Router ID.  The
>> !    generation should be seeded with a variable that is likely to be
>> !    unique in the applicable OSPFv3 router deployment.  A good choice of
>> !    seed would be some portion or hash of the Router-Hardware-Fingerprint
>> !    as described in Section 7.2.2.
>> 
>>   Since there is a possibility of a Router ID collision, duplicate
>>   Router ID detection and resolution are required as described in
>> --- 451,465 ----
>> 
>> 5.  OSPFv3 Router ID Selection
>> 
>> !    An OSPFv3 router requires a unique Router ID within the OSPFv3
>> !    routing domain for correct protocol operation.  An OSPFv3 router
>> !    implementing this specification will select a router-id that has a
>> !    high probability of uniqueness.  A pseudo-random number SHOULD be
>> !    used for the OSPFv3 Router ID.  The generation SHOULD be seeded with
>> !    a variable that is likely to be unique in the applicable OSPFv3
>> !    router deployment.  A good choice of seed would be some portion or
>> !    hash of the Router-Hardware-Fingerprint as described in
>> !    Section 7.2.2.
>> 
>>   Since there is a possibility of a Router ID collision, duplicate
>>   Router ID detection and resolution are required as described in
>> ***************
>> 
>> *** 799,810 ****
>>   automatic pairing between devices.  These mechanisms can help provide
>>   an automatically configured, securely routed network.
>> 
>> !
>> !
>> !
>> !
>> !
>> !
>> 
>> 
>> 
>> --- 799,810 ----
>>   automatic pairing between devices.  These mechanisms can help provide
>>   an automatically configured, securely routed network.
>> 
>> !    In deployments where stronger authentification or encryption is
>> !    required, OSPFv3 IPsec [OSPFV3-IPSEC] or stronger OSPFv3
>> !    Authentication trailer [OSPFV3-AUTH-TRAILER] algorithms MAY be used
>> !    at the expense of additional configuration.  The configuration and
>> !    operational description of such deployments is beyond the scope of
>> !    this document.
>> 
>> 
>> 
>> ***************
>> 
>> 
>> Thanks,
>> Acee 
>> 
>> On 1/13/15, 8:14 PM, "Acee Lindem (acee)" <acee@cisco.com>; wrote:
>> 
>>> Hi Adam, 
>>> 
>>> On 1/13/15, 12:26 PM, "Adam W. Montville" <adam.w.montville@gmail.com>;
>>> 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 draft is ready with comments/nits.
>>>> 
>>>> Comments
>>>> The document describes necessary mechanisms for OSPFv3 to be
>>>> self-configuring in environments requiring such (e.g. IPv6 home
>>>> networks).
>>>> 
>>>> A couple of things stood out to me.  First, I inferred from the document
>>>> that the uniqueness of Router IDs is so within the context of the present
>>>> deployment and not, for example, unique between domains.  This may be
>>>> common knowledge in the world of OSPF, but wasn¹t to me (at least not
>>>> initially).  It could be good to add a sentence about the context of
>>>> Router ID uniqueness early on in the document.
>>> 
>>> I will add a statement to section 5.
>>> 
>>>> 
>>>> Also regarding uniqueness of the ID, Section 5, ³OSPFv3 Router ID
>>>> Selection², indicates that a pseudo-random number SHOULD be used to
>>>> derive the Router ID.  Later in that first paragraph: ³The generation
>>>> should be seeded with a variable that is likely to be unique in the
>>>> applicable OSPFv3 router deployment.²  Should that ³should² be ³SHOULD²?
>>> 
>>> Yes - these two sentences definitely SHOULD be consistent.
>>> 
>>>> 
>>>> The document clearly recognizes the possibility for Router ID collisions,
>>>> and there does not appear to be a need for a cryptographically sound
>>>> pseudo-random number generation - just enough entropy to make the Router
>>>> ID unique within the deployment domain, and the
>>>> Router-Hardware-Fingerprint TLV (Section 7.2.2) is presented as being
>>>> enough.
>>> 
>>> Do you feel that a statement with respect to the pseudo-random algorithm
>>> is necessary? If so, can you suggest some text?
>>> 
>>> 
>>>> 
>>>> Because this document essentially explains the OSPFv3 defaults a router
>>>> should have in order to support auto-configuration, I presumed that the
>>>> security considerations provided in previous OSPFv3 documents would
>>>> essentially be in effect here.  This isn¹t explicitly stated in the
>>>> Security Considerations section, but could be without harm, should they
>>>> apply here.  The bottom line for me is that it seems that OSPFv3
>>>> auto-configuration favors usability over security, but without ignoring
>>>> security entirely (e.g. ³auto-configuration can also be combined with
>>>> password configuration or future extensions for automatic pairing between
>>>> devices.²).
>>> 
>>> I agree with the above except that the document doesn't address all the
>>> available OSPFv3 security options. Let me add a paragraph.
>>> 
>>> I will provide some updated text for review prior to republishing.
>>> 
>>> Thanks,
>>> Acee 
>>> 
>>> 
>> 
>