Re: [DNSOP] Working Group Last Call for draft-ietf-dnsop-dnssec-validator-requirements

[Daniel Migault <[e-mail]>]

Hi,

If you think I have addressed all comments I received, if you believe that
is not the case or if there are other comments, please let me know.
Otherwise I expect to publish a new version by the end of the week.

Yours,
Daniel

On Fri, Jan 13, 2023 at 5:21 PM Daniel Migault <[e-mail]> wrote:

> Hi,
>
> I am just wondering if you have any further comments or thoughts or we
> declare your concerns being addressed. If you think we are fine, just let
> me know.
>
> Yours,
> Daniel
>
> On Tue, Jan 3, 2023 at 7:14 PM Daniel Migault <[e-mail]> wrote:
>
>> Hi Vladimir and Florian,
>>
>> Thanks for the comment regarding the use of 5011, to update the
>> trust anchors. There are two situations where TAs need to be updated:
>> * 1) configuration so the server instances are started with
>> the up-to-date TA.
>> * 2) a running resolver instance that has been started with the old TA
>> and that needs a new TA to be considered.
>>
>> 1) configuration:
>>
>> TA trust store is an essential element of the configuration, and the
>> document recommends having a special process to ensure every new resolver
>> instance starts with the  up-to-date TAs. TAs are so essential in the
>> elaboration of trust that special care must be considered.  This means that
>> you need a robust mechanism to update the TAs trust store.
>> Many DRO will not implement that process and instead rely on software
>> updates to delegate the TA trust store update to the software vendor.
>> If the DRO is willing to have a *special/specific* additional TA that is
>> not updated delegated to the software vendor, the DRO will have to put in
>> place such a mechanism. This is a critical operation and the DRO must have
>> strong reasons to do so and must balance the additional operational risks
>> versus the additional benefits.
>> Given the essential aspect of the TA trust store, we recommend updates to
>> be handled by an automated process (as opposed to manually being performed)
>> BUT we also recommend the process to be manually supervised, that is with a
>> manual confirmation.
>> This mechanism is likely to require a specific relation between the DRO
>> and the TA issuer with potentially the mechanism, being out-of band. To
>> that point 5011 is probably not the best choice as mentioned by 5011 itself
>> in section 8.3.
>>
>> 2) running servers
>>
>> For running resolvers, there is a need to ensure that the resolver is
>> using the up-to-date TA. For this we recommend to follow 5011 that
>> indicates how to automatically put significant trust into the newly
>> published DNSKEY. On the other hand, if resolvers are retarted every days
>> we may not need to have 5011 and monitor the roll over. I think that is the
>> purpose of your comment.
>>
>> My impression is that there were some confusions in the text where 5011
>> was used. When it is limited to the running resolver, I would
>> recommend enabling 5011 when the TA signer implements 5011 in case the
>> software is not updated in a timely manner - or at least let the DRO decide
>> whether it is willing to enable this option as a sort of insurance - even
>> if it is relying on the software update as a general mechanism. I think it
>> might be a bit different from what you proposed initially, which is to
>> leave that to DRO with DNSSEC strong expertise and recommend to
>> only stay with software updates. If there are any strong feelings on just
>> relying on software updates and leaving 5011 to DNSSEC experts, I am also
>> fine to push toward such a direction.
>>
>> I updated the text as follows:
>> * clarifying TA updates for configuration versus running instances
>> * clarifying 5011 dot not apply for updating configuration - at least as
>> a primary mechanism
>> * emphasize that the non default model is only recommended for DRO with
>> DNSSEC expertise
>> * adding that TA update for running resolver may be performed also by
>> software update under the condition the DRO is likely to ensure a very
>> recent release is run.
>> * add a recommendation that when 5011 is used, the signer needs to
>> implement 5011 timings.
>>
>> The changes can be seen there:
>>
>> https://github.com/mglt/draft-mglt-dnsop-dnssec-validator-requirements/commit/dbb75b72a1806520ac77cf04424b0f6de0df29b5
>>
>> Yours,
>> Daniel
>>
>> On Sun, Nov 27, 2022 at 7:26 AM Florian Obser <[e-mail]>
>> wrote:
>>
>>> On 2022-11-25 12:26 -05, Daniel Migault <[e-mail]> wrote:
>>> > On Wed, Nov 23, 2022 at 10:29 AM Vladimír Čunát <
>>> [e-mail]>
>>> > wrote:
>>> >> I am surprised  you would not recommend RFC 5011
>>> >>
>>> >> 5011 needs persistent state, a thing that resolvers/validators often
>>> don't
>>> >> need at all otherwise (cache is safe to delete).  5011 doesn't always
>>> work,
>>> >> so you need to combine with some fallback mechanism(s) anyway - for
>>> new
>>> >> installations and for stale ones (missed rotation).  Root rollover has
>>> >> happened only once in history, non-root TAs aren't that common, and
>>> 5011
>>> >> algorithm isn't very simple, so the code can easily get some bugs
>>> without
>>> >> anyone noticing until it's too late.
>>> >>
>>> >> Lots of down-sides, so I rather put the TAs into SW updates, for the
>>> root
>>> >> TA case at least.  I'd recommend trying to avoid non-root TAs, but if
>>> I had
>>> >> to choose, I'd put them into configuration.  Again a thing that I
>>> have to
>>> >> provision *anyway*, so I get the occasional TA updates basically for
>>> free,
>>> >> without needing to worry about those 5011 disadvantages.  (occasional
>>> =
>>> >> 5011 defaults to requiring 30 days of overlap)
>>> >>
>>> >>
>>> > Oh! sure for the TA. My understanding of the text is that it recommends
>>> > 5011 for running instances, but that new instances are configured with
>>> > up-to-date TA that in most cases are updated by software update. So
>>> yes I
>>> > agree and will check this appears clearly.
>>>
>>> Another issue with 5011 is that it needs cooperation from the entity
>>> signing the zone during a KSK rollover. 7583 spells this out in section
>>> 2.2. I think Vladimír is hinting at this already, I'd say it should be
>>> spelled out. Especially since this is aimed at non-DNSSEC-Experts as you
>>> were saying earlier in the thread.
>>>
>>> If a DRO unilaterally decides to put in a TA for example.com as
>>> suggested in section 7.1.1 and using 5011 this will not end well if they
>>> don't tell the people operating the signer. They will probably not
>>> follow the correct timing during a KSK roll.
>>>
>>
>>
>> --
>> Daniel Migault
>> Ericsson
>>
>
>
> --
> Daniel Migault
> Ericsson
>


-- 
Daniel Migault
Ericsson