[keycloak-user] Log out server sessions when using bearer authentication

[Dan Østerberg]

That was actually a third alternative that we also initially considered, but discarded. We wouldn’t get single-sign-out on open URLs, and sign-out would be delayed. It’s not ideal, but in practice it would probably be OK… except that later on in the request, Undertow (in Wildfly) would throw an exception whenever someone invoked getSession(...) and used the returned object. However, apparently there are several bug fixes for this in Undertow, so we can attempt to upgrade and try this approach out. Thanx for the reminder.

~Dan

Fra: Stian Thorgersen [mailto:sthorger at redhat.com]
Sendt: tirsdag 3. januar 2017 10.53
Til: Dan Østerberg <dan at ren.no>
Kopi: keycloak-user at lists.jboss.org
Emne: Re: [keycloak-user] Log out server sessions when using bearer authentication

What about a simple filter that looks at the session state from the token and associates it with the http session if one is set? If the tokens session state is different to the http session invalidate it.

On 3 January 2017 at 10:39, Dan Østerberg <dan at ren.no<mailto:dan at ren.no>> wrote:
Yes, avoiding to store any security related stuff in the session would ensure that authentication / permissions are read from the current access token. But… the entire problem isn’t solved, since the server session still won’t be invalidated. Lets say I log in and trigger some REST calls. For some of those, a session is created, storing my personal information. Then I log out – from Keycloak. You log in, and get a new security context but can access my personal information still stored in my old server session. (Naturally, this also goes for the same user logging in again – seing old session data that he shouldn’t see. It’s just a less severe issue.)

When logging out normally, the client can trigger logout from all x webapps it (might) have accessed. But that won’t happen when logging out via another webapp, or kicking out a session from Keycloak admin console.

Maybe the problem isn’t so big if all precautions are taken. But it’s still a problem, and I still can’t see how it can be completely solved other than by one of the two approaches I outlined.

~Dan

Fra: Stian Thorgersen [mailto:sthorger at redhat.com<mailto:sthorger at redhat.com>]
Sendt: tirsdag 3. januar 2017 10.26

Til: Dan Østerberg <dan at ren.no<mailto:dan at ren.no>>
Kopi: keycloak-user at lists.jboss.org<mailto:keycloak-user at lists.jboss.org>
Emne: Re: [keycloak-user] Log out server sessions when using bearer authentication

As I suggested just make sure the sessions don't contain the security context and that all requests that require security include an access token even when there is a session. Problem solved.

Or the much more complicated approach and find some way of centrally track all sessions to all REST services to destroy all session on logout. Keycloak can't do that as we only track sessions from application that do the actual login not services that are invoked by those applications.

On 3 January 2017 at 10:06, Dan Østerberg <dan at ren.no<mailto:dan at ren.no>> wrote:
The other way around – to _mainly_ use stateless REST services. With client-controlled tokens.

The fact that single-sign-out wont affect the client until token renewal is attempted is OK. And in most cases we’ll even eagerly detect that, using a simple a cookie-logic. But the problem is if/when some REST call creates a session. Then that session won’t be invalidated, even if the user (or another user) logs into Keycloak again. We need to address that somehow.

As I see it, we either need to:

1)      Prevent session creation. Easy said, but we don’t control all code, and it’s fairly easy for one programmer to accidentally e.g. inject a session-scoped WELD bean in code reachable from a REST service. If going for this route, we’d at least need mechanisms for detecting if a session was after all created, and notify developers plus maybe auto-destroy it. Or wrap the request so that sessions aren’t created (with uncertain consequences). Since parts of the webapps + shared libraries might be used statefully, it gets a bit messy.

2)      Connect all sessions to the single-sign-out controller (Keycloak).

I evaluated 2) to be the cleaner approach, but wanted to know if Keycloak has some built-in solution.

~Dan

Fra: Stian Thorgersen [mailto:sthorger at redhat.com<mailto:sthorger at redhat.com>]
Sendt: tirsdag 3. januar 2017 08.52

Til: Dan Østerberg <dan at ren.no<mailto:dan at ren.no>>
Kopi: keycloak-user at lists.jboss.org<mailto:keycloak-user at lists.jboss.org>
Emne: Re: [keycloak-user] Log out server sessions when using bearer authentication

Not really following what you are saying. Are you saying you want your REST services to be stateful and use cookie based security rather than tokens? Or the other way around?

On 3 January 2017 at 08:40, Dan Østerberg <dan at ren.no<mailto:dan at ren.no>> wrote:
Thanx for the reply. But wouldn’t that be a bit against the whole point with token based authentication? We’ve used Jasig CAS before, and thereby used internal server-only authentication + server session. That’s very similar to Keycloak used the way you describe – and limiting in several ways. If that was the only option, we would have stayed with CAS. Being stateless & having more control in the client is certainly beneficial in a client-heavy REST-based application, where the client accesses multiple webapps (within the same realm).

I guess we’ll just have to implement some in-house solution then...

~Dan

Fra: Stian Thorgersen [mailto:sthorger at redhat.com<mailto:sthorger at redhat.com>]
Sendt: mandag 2. januar 2017 15.16
Til: Dan Østerberg <dan at ren.no<mailto:dan at ren.no>>
Kopi: keycloak-user at lists.jboss.org<mailto:keycloak-user at lists.jboss.org>
Emne: Re: [keycloak-user] Log out server sessions when using bearer authentication

There's no standard way of doing backchannel logout with OAuth2. There's a draft spec for OpenID Connect that we may implement in the future.

Keycloak has it's own proprietary backchannel logout, but that's only for applications that do the login. In your case as it's a JS app that obtains the tokens there's no backchannel logout involved and instead it relies on the session cookie + access token timeout. Assuming your JEE app is a rest service it should create a session that allows invoking without a access token from the JS app. That way it won't be possible for the JS app to invoke it once the session is logged out as it won't be able to obtain new access tokens.

On 29 December 2016 at 11:27, Dan Østerberg <dan at ren.no<mailto:dan at ren.no>> wrote:
Hi,

How can we make single sign out work when passing bearer tokens to a server guarded by a «traditional» session based Oauth2 client / adapter?

Lets say we use bearer authentication via the Javascript adapter, and make REST requests to a stateless (no session) server. Lets further say that during some later request, a server session will be created – either intentionally to store state, or unintentionally e.g. by some shared code (since sessions are auto-created in Java EE). Now single sign out won’t work, because Keycloak is neither aware of the server session nor the Oauth2 client that has an admin URL.

One solution could be to detect the creation of a session, and internally via an extended REST API tell the Keycloak server to create a session also for the client with admin URL (connecting it to the created session ID). But it just sounds as if this should be covered out-of-the-box, so maybe I’m just missing or misunderstanding something...

~Dan
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