Re: [OSPF] One more RFC 6506BIS Clarification

[Anton Smirnov <[e-mail]>]

    Hi Acee,
    RFC 6506 inherited this property from RFC 5709 which has this text 
word for word:

>                         In the event that the last key associated
>     with an interface expires, it is unacceptable to revert to an
>     unauthenticated condition, and not advisable to disrupt routing.
>     Therefore, the router should send a "last Authentication Key
>     expiration" notification to the network manager and treat the key as
>     having an infinite lifetime until the lifetime is extended, the key
>     is deleted by network management, or a new key is configured.

To me this property looks wrong from security point of view and in 
general I would agree to have it removed. OTOH difference between v2 and 
v3 specs is highly undesirable, so if RFC 6506 is changed so that this 
property is dropped (or made optional) then at the same time we should 
evaluate how the same change can be pushed into RFC 5709.

Anton






On 10/08/2013 12:35 AM, Acee Lindem wrote:
> Hi Mike,
> I agree and don't see why this one configuration error should be handled explicitly when there are many other possible errors. Actually, I'd looked at this text before and meant to address it since I'd never implement this. I'll discuss with the other authors.
> Thanks,
> Acee
>
> On Oct 7, 2013, at 6:19 PM, Mike Dubrovskiy (mdubrovs) wrote:
>
>> Hi Acee,
>>
>> I like the change but we currently have the following text in rfc6506
>>
>>    "In the event that the last key associated
>>    with an interface expires, it is unacceptable to revert to an
>>    unauthenticated condition and not advisable to disrupt routing.
>>    Therefore, the router SHOULD send a "last Authentication Key
>>    expiration" notification to the network operator and treat the key as
>>    having an infinite lifetime until the lifetime is extended, the key
>>    is deleted by the network operator, or a new key is configured."
>>
>> The above text is difficult to apply to Accept keys. It should be either deleted
>> or modified.
>>
>> Thank you,
>> Mike
>>
>>> -----Original Message-----
>>> From: [e-mail] [mailto:[e-mail]] On Behalf Of
>>> Acee Lindem
>>> Sent: Monday, October 07, 2013 1:25 PM
>>> To: OSPF List
>>> Subject: [OSPF] One more RFC 6506BIS Clarification
>>>
>>> One more thing I intend to add is explicit specification that the OSPFv3 packet
>>> should be dropped if the Security Association isn't found or has expired. The
>>> text is analogous to the original RFC 2328 Appendix D text. This will be added
>>> to section 4.6.
>>>
>>> ***************
>>> *** 976,981 ****
>>> --- 976,986 ----
>>>      and the IPv6 header length is less than the amount necessary to
>>>      include an Authentication Trailer.
>>>
>>> +    Locate the receiving interface's OSPFv3 SA using the SA ID in the
>>> +    received AT.  If the SA is not found, or if the SA is not valid for
>>> +    reception (i.e., current time < KeyStartAccept or current time >=
>>> +    KeyStopAccept), the OSPFv3 packet is dropped.
>>> +
>>>      If the cryptographic sequence number in the AT is less than or equal
>>>      to the last sequence number in the last OSPFv3 packet of the same
>>>      OSPFv3 type successfully received from the neighbor, the OSPFv3
>>>
>>> Although I would hope no one would complain about this since it was always
>>> implied in section 3 (see excerpt below), please speak now if you have any
>>> concerns.
>>>
>>>    o  Security Association Identifier (SA ID)
>>>
>>>       This is a 16-bit unsigned integer used to uniquely identify an
>>>       OSPFv3 SA, as manually configured by the network operator.
>>>
>>>       The receiver determines the active SA by looking at the SA ID
>>>       field in the incoming protocol packet.
>>>
>>>
>>>
>>>
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