Re: [Acme] Obtaining the Tor hidden service descriptor for draft-ietf-acme-onion

[Q Misell <[e-mail]>]

The rationale for expiry is that in the case of http-01 or tls-alpn-01 the
ACME client need not have access to the Onion service's secret key. A long
lived CAA signature could be generated with the key, provided to the ACME
client to use, and the key could be kept away from the ACME client and only
available on the machine running the Tor proxy.
------------------------------

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On Tue, 17 Oct 2023 at 04:15, Seo Suchan <[e-mail]> wrote:

>
> not sure giving expiry by client side is meaningful: as we send this at
> finalization step, and as something would be very wrong if one request
> another certificate in 8 hours from last certificate so whatever value
> client may put there will be expired by the time we request: in effect it'd
> be act more like timestamp and if it is I kinda want it to be nonce for
> that certificate finalization explicitly.
> 2023-10-17 오전 3:10에 Q Misell 이(가) 쓴 글:
>
> Hi all,
>
> In-band CAA is now implemented on the reference CA at
> https://acmeforonions.org and in the certbot-onion
> <https://pypi.org/project/certbot-onion/> plugin.
> draft-ietf-acme-onion-01 has also been published with the in-band CAA spec
> (refined from my last email from issues that arose during implementation).
>
> Cheers,
> Q
> ------------------------------
>
> Any statements contained in this email are personal to the author and are
> not necessarily the statements of the company unless specifically stated.
> AS207960 Cyfyngedig, having a registered office at 13 Pen-y-lan Terrace,
> Caerdydd, Cymru, CF23 9EU, trading as Glauca Digital, is a company
> registered in Wales under № 12417574
> <https://find-and-update.company-information.service.gov.uk/company/12417574>,
> LEI 875500FXNCJPAPF3PD10. ICO register №: ZA782876
> <https://ico.org.uk/ESDWebPages/Entry/ZA782876>. UK VAT №: GB378323867.
> EU VAT №: EU372013983. Turkish VAT №: 0861333524. South Korean VAT №:
> 522-80-03080. AS207960 Ewrop OÜ, having a registered office at Lääne-Viru
> maakond, Tapa vald, Porkuni küla, Lossi tn 1, 46001, trading as Glauca
> Digital, is a company registered in Estonia under № 16755226. Estonian VAT
> №: EE102625532. Glauca Digital and the Glauca logo are registered
> trademarks in the UK, under № UK00003718474 and № UK00003718468,
> respectively.
>
>
> On Fri, 13 Oct 2023 at 17:19, Q Misell <[e-mail]> wrote:
>
>> I've found some time to specify in-band CAA, a quick first draft is in
>> the working draft[1]. Looking forward to hearing people's thoughts.
>>
>> [1]:
>> https://as207960.github.io/acme-onion/draft-ietf-acme-onion.html#name-alternative-in-band-present
>> ------------------------------
>>
>> Any statements contained in this email are personal to the author and are
>> not necessarily the statements of the company unless specifically stated.
>> AS207960 Cyfyngedig, having a registered office at 13 Pen-y-lan Terrace,
>> Caerdydd, Cymru, CF23 9EU, trading as Glauca Digital, is a company
>> registered in Wales under № 12417574
>> <https://find-and-update.company-information.service.gov.uk/company/12417574>,
>> LEI 875500FXNCJPAPF3PD10. ICO register №: ZA782876
>> <https://ico.org.uk/ESDWebPages/Entry/ZA782876>. UK VAT №: GB378323867.
>> EU VAT №: EU372013983. Turkish VAT №: 0861333524. South Korean VAT №:
>> 522-80-03080. AS207960 Ewrop OÜ, having a registered office at Lääne-Viru
>> maakond, Tapa vald, Porkuni küla, Lossi tn 1, 46001, trading as Glauca
>> Digital, is a company registered in Estonia under № 16755226. Estonian VAT
>> №: EE102625532. Glauca Digital and the Glauca logo are registered
>> trademarks in the UK, under № UK00003718474 and № UK00003718468,
>> respectively.
>>
>>
>> On Tue, 10 Oct 2023 at 21:22, Q Misell <[e-mail]> wrote:
>>
>>> Hi Silvio,
>>>
>>> Thanks for that info, that's quite helpful.
>>>
>>> I think the idea of allowing the client to just send the CAA lines
>>> signed by its key would work well, and remove most if not all of the
>>> problems I've been running into.
>>> I'll work on implementing that in my draft, and see how difficult it'd
>>> be to get that part only working in Boulder (as Let's Encrypt have already
>>> indicated that they won't be implementing http-01 and tls-alpn-01 for
>>> hidden services).
>>>
>>> Cheers,
>>> Q
>>> ------------------------------
>>>
>>> Any statements contained in this email are personal to the author and
>>> are not necessarily the statements of the company unless specifically
>>> stated. AS207960 Cyfyngedig, having a registered office at 13 Pen-y-lan
>>> Terrace, Caerdydd, Cymru, CF23 9EU, trading as Glauca Digital, is a company
>>> registered in Wales under № 12417574
>>> <https://find-and-update.company-information.service.gov.uk/company/12417574>,
>>> LEI 875500FXNCJPAPF3PD10. ICO register №: ZA782876
>>> <https://ico.org.uk/ESDWebPages/Entry/ZA782876>. UK VAT №: GB378323867.
>>> EU VAT №: EU372013983. Turkish VAT №: 0861333524. South Korean VAT №:
>>> 522-80-03080. AS207960 Ewrop OÜ, having a registered office at Lääne-Viru
>>> maakond, Tapa vald, Porkuni küla, Lossi tn 1, 46001, trading as Glauca
>>> Digital, is a company registered in Estonia under № 16755226. Estonian VAT
>>> №: EE102625532. Glauca Digital and the Glauca logo are registered
>>> trademarks in the UK, under № UK00003718474 and № UK00003718468,
>>> respectively.
>>>
>>>
>>> On Tue, 10 Oct 2023 at 20:14, rhatto <[e-mail]> wrote:
>>>
>>>> On Thu, Sep 07, 2023 at 04:55:51PM +0100, Q Misell wrote:
>>>> > I've had some discussion recently with the Tor project on
>>>> implementation
>>>> > hurdles for draft-ietf-acme-onion. One concern that has been raised
>>>> by a few is
>>>> > the need to run a Tor client to validate requests, even with
>>>> onion-csr-01, due
>>>> > to the inclusion of CAA in the draft.
>>>>
>>>> Hi Q, and thanks for bringing this up.
>>>>
>>>> > One solution proposed to this is that the ACME client MAY[1] send the
>>>> hidden
>>>> > service descriptor to CA as part of the finalize request. The CA also
>>>> MAY
>>>> > require this, if they do not wish to run a Tor client. This, to my
>>>> knowledge,
>>>> > wouldn't reduce the security of the validation of CAA, as the
>>>> descriptor
>>>> > document is still cryptographically validated in the same way using
>>>> the current
>>>> > network consensus. Additionally the directory authorities that serve
>>>> > descriptors are already non-trusted actors in Tor.
>>>> >
>>>> > The CA would still need a copy of the network consensus document to
>>>> verify
>>>> > the descriptor submitted by the client. Most directory authorities
>>>> however
>>>> > are reachable over standard HTTP over TCP, in addition to HTTP over
>>>> Tor.
>>>> > This would allow the CA to fetch the current consensus without any
>>>> > connection to Tor. The consensus fetched this way would still be
>>>> verified
>>>> > against the trusted directory authorities of Tor[2].
>>>>
>>>> Specifically, the "valid-after", "fresh-until", and "hsdir_interval" are
>>>> the only consensus items needed to parse, decrypt and validate an Onion
>>>> Service descriptor.
>>>>
>>>> > What are people's thoughts on this, and more importantly, what
>>>> problems do
>>>> > people see with this?
>>>>
>>>> After a lengthy discussion with Tor developers, we suggest the following
>>>> options, prioritizing the least complex:
>>>>
>>>> 0. ACME clients MAY send "valid-after", "fresh-until" and "hs_interval"
>>>>    along with the descriptor, which would allow the ACME Server to
>>>> verify
>>>>    CAA in a stateless way, without bootstrapping Tor to fetch the
>>>>    descriptor and without fetching the network consensus.
>>>>
>>>> 1. Only the descriptor is sent by the ACME client, so the ACME server
>>>> would
>>>>    need to fetch and cache the network consensus.
>>>>
>>>> 2. The ACME client does not send the descriptor, leaving to the ACME
>>>> server
>>>>    the job of fetching it, as stated on draft-ietf-acme-onion-00.
>>>>
>>>> For options 0 and 1 above, there are two ways that a consensus (or just
>>>> the
>>>> needed items) can be fetched either by ACME clients or servers:
>>>>
>>>> a. Through the Tor network, from one of many directory caches.
>>>>
>>>>    As this involves bootstrapping Tor, it makes more sense for ACME
>>>>    clients to do this fetching, as clients are probably already
>>>> connected
>>>>    to Tor in order to run an Onion Service or to make the ACME request
>>>>    through Tor.
>>>>
>>>> b. Doing HTTP over TCP, or HTTP over Tor to the directory authorities.
>>>>
>>>>    While this is supported nowadays, it's not guaranteed to work in the
>>>>    long term, since this method is deprecated in favor of the approach
>>>>    above, and DirAuths may even stop serving the consensus directly by
>>>> HTTP
>>>>    at some point.
>>>>
>>>>    This also requires checking the DirAuths' signatures in the consensus
>>>>    document.
>>>>
>>>> > Should this be incorporated into the draft?
>>>>
>>>> Yes, we support this idea, but also note that, despite parsing and
>>>> validating an .onion descriptor being relatively straightforward, it
>>>> involves more code to be maintained.
>>>>
>>>> We understand that signed CAA parameters could be accepted directly in
>>>> an ACME API request without reducing security and the need to process an
>>>> entire descriptor.
>>>>
>>>> --
>>>> Silvio Rhatto
>>>> pronouns he/him
>>>> _______________________________________________
>>>> Acme mailing list
>>>> [e-mail]
>>>> https://www.ietf.org/mailman/listinfo/acme
>>>>
>>>
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