[Openid-specs-mobile-profile] Async authentication with polling and callback
Torsten Lodderstedt
torsten at lodderstedt.net
Tue Dec 27 15:57:04 UTC 2016
Hi Petteri,
as promised during the last WG call, please find below my detailed
feedback on your proposal:
Your proposal consists of two distinct contributions:
(1) a generic http level mechanism to control client/server interaction
using standard HTTP status codes
(2) a pattern to turn push-style into pull-style data retrival
I think the WG needs more concrete examples to understand the nature and
benefits of those contributions. I suggest to treat them separately
since they can be discussed and potentially adopted independently.
Regarding (1) I would suggest you to provide an example of how UQ or
CIBA could be represented.
Regarding (2) I suggest you to provide the WG with a concrete example
for CIBA (since this was the subject of the discussion where you made
this proposal for the first time). In order to facilitate comparability,
I would propose you do so based on the the application leven control
mechanism as defined in the CIBA spec (incl. fetching the tokens from
the token endpoint). Moreover, there is the need for a threat analysis
of this flow. You state your proposal will remove the need to
authenticate the caller (OP/AS). I'm not convinsed since any attacker
could obviously call (flood) the clients notification endpoint and cause
the client to send any opaque value to the OP/AS. Don't you think this
must be prevented?
and indeed, such an analysis must be conducted for the proposal defined
in the CIBA spec as well!
best regards,
Torsten.
Am 07.12.2016 um 10:15 schrieb Petteri Stenius:
>
> Hi Torsten.
>
> You are right, it is better not to mix the modes of the endpoints.
>
> Petteri
>
> *From:*Torsten Lodderstedt [mailto:torsten at lodderstedt.net]
> *Sent:* maanantaina 5. joulukuuta 2016 22.33
> *To:* Petteri Stenius <Petteri.Stenius at ubisecure.com>
> *Cc:* openid-specs-mobile-profile at lists.openid.net
> *Subject:* Re: [Openid-specs-mobile-profile] Async authentication with
> polling and callback
>
> Hi,
>
> Am 05.12.2016 um 13:18 schrieb Petteri Stenius:
>
> Hi,
>
> Registration of endpoints is an application level issue, not part
> of the generalized http level mechanism.
>
>
> but it somehow intervenes with the generic http level mechanism, so
> the generic http part is not self-explanatory.
>
>
> With OAuth/OIDC we should follow the convention of registering
> endpoints with client registration and provider metadata.
>
> The UQ draft defines a new client registration value
> “client_notification_endpoint” for the callback, but would it not
> be possible to use “redirect_uris” for this purpose?
>
>
> Do you think this is a good idea to mix the two different modes? The
> rules for processing a conventional redirect (XSRF, referrer header,
> session state/cookies) are different from receiving a server2server
> callback (e.g. IP address black/whitelisting). I would prefer to keep
> them separate.
>
>
> The client callback endpoint is an entry in the redirect_uris
> array of client registration metadata. With a parameter of the
> request that starts async authentication client indicates at which
> of the registered endpoints it wishes to receive the async
> callback. This is comparable to authorization code request.
>
> Petteri
>
>
> best regards,
> Torsten.
>
> ------------------------------------------------------------------------
>
> *From:*Torsten Lodderstedt <torsten at lodderstedt.net>
> <mailto:torsten at lodderstedt.net>
> *Sent:* Saturday, December 3, 2016 10:50:10 AM
> *To:* Petteri Stenius
> *Cc:* openid-specs-mobile-profile at lists.openid.net
> <mailto:openid-specs-mobile-profile at lists.openid.net>
> *Subject:* Re: [Openid-specs-mobile-profile] Async authentication
> with polling and callback
>
> Hi Petteri,
>
> thanks for your proposal.
>
> One question popped up when I read the sequence for the callback
> case: how does the server know where to send the callback in step 3?
>
> best regards,
>
> Torsten.
>
>
> Am 01.12.2016 um 16:58 schrieb Petteri Stenius
> <Petteri.Stenius at ubisecure.com
> <mailto:Petteri.Stenius at ubisecure.com>>:
>
> Hello everybody
>
> At the Paris meeting in September there was some discussion
> about polling and callback mechanisms related to asynchronous
> functions.
>
> These mechanisms exist in both UQ and SIBA draft
> specifications. Polling is also defined in OAuth Device Flow
> draft.
>
> This proposal is an attempt to generalize async polling and
> callback mechanisms:
>
> ·Define polling on the http level, not an application level
> function
>
> ·Callback is only a simple notification request, a client
> initiated request is required to fetch the actual content
>
> The two proposals work together, and make for example
> switching between polling and callback mechanisms very easy.
>
> Thanks,
>
> Petteri
>
> *Polling defined on the http level*
>
> Define mechanism with HTTP 303 redirect and Retry-After
> response header.
>
> 303 redirect is used to define polling as sequence of http
> redirects the client follows until async operation completes
> and response appears.
>
> The client MUST wait time indicated by Retry-After header
> before following a redirect. Failing to do so would result in
> 503 Service Unavailable error (with Retry-After header).
>
> Semantics is comparable to "Wait a moment, the response will
> soon appear at this location"
>
> The server is allowed to implement "long polling" by holding a
> response up to 30 seconds (see
> https://tools.ietf.org/html/rfc6202#section-5.5)
>
> Example of polling sequence:
>
> 1.Client begins async operation
>
> POST /begin-async-operation HTTP/1.1
>
> 2.Server response with 303 status indicates client must begin
> polling for response. Server encodes state into querystring of
> redirect uri
>
> HTTP/1.1 303 See Other
>
> Location: /async-response?opaque-server-state-1
>
> Retry-After: 10
>
> 3.Client waits at least 10 seconds before following the redirect
>
> GET /async-response?opaque-server-state-1 HTTP/1.1
>
> 4.Server response with new uri where querystring has changed
>
> HTTP/1.1 303 See Other
>
> Location: /async-response?opaque-server-state-2
>
> Retry-After: 10
>
> 5.Client again waits before following the redirect
>
> GET /async-response?opaque-server-state-2 HTTP/1.1
>
> 6.Server response with content when async operation has completed
>
> HTTP/1.1 200 OK
>
> "completed"
>
> *Callback is a simple notification request*
>
> My proposal for callback mechanism is a simple notification
> request.
>
> Server encodes any state it needs into querystring of the
> notification request.
>
> For the client the querysring is opaque and the client must
> pass it as-is when fetching the actual content from the server.
>
> Using a simple notification request removes the requirement
> for client to authenticate the callback request from server.
>
> Example of callback sequence:
>
> 1.Client begins async operation
>
> POST /begin-async-operation HTTP/1.1
>
> 2.Server response with 202 status indicates client needs to
> wait for callback
>
> HTTP/1.1 202 Accepted
>
> 3.When async operation completes server sends a notification
> request to client. Server encodes state into querystring of
> notification uri
>
> GET /callback?opaque-server-state-3 HTTP/1.1
>
> 4.Client response is not processed by server
>
> HTTP/1.1 204 No Content
>
> 5.Client creates request uri and fetches content from server
>
> GET /async-response?opaque-server-state-3 HTTP/1.1
>
> 6.Server response with content
>
> HTTP/1.1 200 OK
>
> "completed"
>
> *Related discussion*
>
> [Openid-specs-mobile-profile] Async authentication
>
> http://lists.openid.net/pipermail/openid-specs-mobile-profile/Week-of-Mon-20161010/000615.html
>
> [OAUTH-WG] polling in the device flow
>
> https://www.ietf.org/mail-archive/web/oauth/current/msg02939.html
>
> [OAUTH-WG] Device Flow: Alternative to Polling
>
> https://www.ietf.org/mail-archive/web/oauth/current/msg16723.html
>
> *References*
>
> OAuth 2.0 Device Flow
>
> https://tools.ietf.org/html/draft-ietf-oauth-device-flow-03
>
> HTTP/1.1 Semantics and Content
>
> https://tools.ietf.org/html/rfc7231
>
> Retry-After
>
> https://tools.ietf.org/html/rfc7231#section-7.1.3
>
> Best Practices for the Use of Long Polling
>
> https://tools.ietf.org/html/rfc6202
>
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