Re: [secdir] Secdir last call review of draft-ietf-ospf-ospfv3-segment-routing-extensions-16

Peter Psenak <ppsenak@cisco.com> Fri, 09 November 2018 11:44 UTC

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Date: Fri, 09 Nov 2018 12:44:20 +0100
From: Peter Psenak <ppsenak@cisco.com>
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To: Yaron Sheffer <yaronf.ietf@gmail.com>, secdir@ietf.org
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Subject: Re: [secdir] Secdir last call review of draft-ietf-ospf-ospfv3-segment-routing-extensions-16
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Hi Yaron,

On 06/11/18 07:13 , Yaron Sheffer wrote:
> Thank you Peter, this addresses my comments.

latest version (17) includes your comments.

thanks,
Peter

>
>      Yaron
>
> On 05/11/2018 10:12, Peter Psenak wrote:
>> Hi Yaron,
>>
>> thanks for your comments, please see inline:
>>
>>
>> On 04/11/18 16:38 , Yaron Sheffer wrote:
>>> Reviewer: Yaron Sheffer
>>> Review result: Has Nits
>>>
>>> Summary: document has non-security related nits.
>>>
>>> Details
>>>
>>> * The definition of "segment" is different here from the one used in the
>>> architecture RFC. The RFC is more abstract, quoting: A node steers a
>>> packet
>>> through an ordered list of instructions, called "segments". Whereas
>>> here a
>>> segment is simply a sub-path. This is confusing to a non-expert, and
>>> perhaps
>>> indicates a change in the group's thinking.
>>
>> the definition in this draft relates to segment as used by IGPs, in
>> which case a segment represents the sub-path. There are other segments
>> outside of IGPs which can represent other things, but they are not
>> covered by this draft.
>>
>>
>>>
>>> * SID/Label Sub-TLV: is it Mandatory? If so, please point it out.
>>
>> SID/Label Sub-TLV is not advertised on its own. It is advertised as a
>> sub-TLV of the:
>>
>> 3.2.  SID/Label Range TLV
>> 3.3.  SR Local Block TLV
>>
>> Both of these section specify that SID/Label Sub-TLV MUST be included.
>>
>>>
>>> * "The SR-Algorithm TLV is optional" - I find this sentence
>>> confusing. Maybe
>>> replace by "The SR-Algorithm TLV is mandatory for routers that implement
>>> segment routing"?
>>
>>
>> the text says:
>>
>>     "If the SR-Algorithm TLV
>>     is not advertised by the node, such node is considered as not being
>>     segment routing capable."
>>
>> Isn't that sufficient?
>>
>>
>>>
>>> * The reference under "IGP Algorithm Type" registry should be to the
>>> IANA
>>> registry itself, not to the I-D that defines it. (In particular since
>>> the IANA
>>> registry has already been established,
>>> https://www.iana.org/assignments/igp-parameters/igp-parameters.xhtml#igp-algorithm-types).
>>>
>>
>> I got another comment from Opsdir last call review to include the I-D
>> that defined it. I Added them both, hopefully that satisfy everybody.
>>
>>>
>>> * OSPFv3 Extended Prefix Range TLV Flags octet: add the usual
>>> incantation about
>>> reserved bits.
>>
>> Done.
>>
>>
>>
>>
>>> * In general I agree with the reasoning in the Security
>>> Considerations. I would
>>> like to raise the question if, in addition to mis-routing, this adds
>>> a threat
>>> of massive denial-of-service on MPLS endpoints, e.g. by allowing an
>>> attacker
>>> who has OSPF access to introduce routing loops. (This may be
>>> completely bogus,
>>> I am far from expert with either of these protocols).
>>
>> above is addressed by usage of the usage of the OSPF authentication as
>> described in the security section.
>>
>> thanks,
>> Peter
>>
>>>
>>> .
>>>
>>
> .
>