[keycloak-dev] Better support for "scope" in adapters

[Pedro Igor Silva]

I'm not sure if we need to consider that in our adapters.

Usually, the front-end knows the set of scopes that it needs to interact
with the backend and stay functional. And the backend by itself is free to
exchange tokens to call other services (service chaining).

One thing that makes sense though is "incremental authorization" and allow
apps to request additional scopes during an authentication session, so the
app gets what was previously granted and the new scopes (depending on user
consent). But I think we support that already, right ?

Regards.
Pedro Igor

On Tue, Jan 29, 2019 at 9:36 AM Marek Posolda <mposolda at redhat.com> wrote:

> During my work on Client Scopes last year, I did not any work on the
> adapters side. I think there is a space for improvement here. I will try
> to summary current issues and some initial proposals for improve things.
> Suggestions welcomed! And sorry for longer email :)
>
>
> Both javascript adapter and servlet adapter has some way for requesting
> the additional "scope" and ensure that that initial OIDC authentication
> request sent to Keycloak will contain some custom "scope" parameter. The
> javascript adapter has support for "scope" as an option of the "login"
> method [1]. The servlet adapter has a possibility to inject custom
> "scope" with parameters forwarding [2]. I am not sure about node.js and
> other adapters TBH. But even for javascript and servlet adapter, the
> current support is quite limited for few reasons. For example:
>
> - The approach of parameters forwarding used in servlet adapters
> requires to logout before requesting the additional scope. Because  when
> I am already authenticated in the application and I open secured URL
> like http://localhost/app/secured?scope=some-custom-scope, the adapter
> will just ignore it in case that user is already logged-in and it will
> automatically forward to the application.
>
> - Both servlet and javascript adapters support to have just single
> "triplet" of tokens per browser session. In this context "triplet" means
> the single set of 3 tokens (ID token , Access Token , Refresh token). So
> for example when I want to request the custom scope for being able to
> invoke "service1", I can use "scope=service1". However after Keycloak
> redirects me back to the application, the existing triplet of tokens is
> just replaced with the new one for "service1" . Then when I want to
> later invoke another service like "service2", I need to request the
> additional scope "scope=service2", which will replace my tokens on the
> adapter's side with the "service2" tokens . But then later when I want
> to switch again to "service1", I need to redirect to Keycloak again as
> the current triplet of tokens for "service1" etc.
>
>
> To improve this limitation, I think that it will be good if adapters
> easily support the following:
>
> - Instead of having single triplet of tokens, it will be good if
> adapters can contain Map of tokens. Key of the map can be "scope"
> parameter. So for example, the adapter will have "default" tokens
> (those, which were used for initial login), the tokens for "service1"
> and the tokens for "service2" .
>
> - It will be nice if there is easy way to ask adapter for "service1"
> scope. In case that I don't have yet this scope, adapter will redirect
> me to Keycloak with "scope=service1". If I already have it, adapter will
> return me an existing token. If existing access token is expired,
> adapter will refresh the access token for requested scope in the
> background and return me the "updated" token.
>
> - When I want to invoke service1 and I need to use "scope=service1", I
> usually need just access token and refresh token. I don't need ID Token
> anymore. I also don't need the "profile" and "email" claims to be
> returned in the new access token. This is related to the JIRA of having
> the server-side support for client scopes like (always, default,
> optional) instead of current (default, optional) [3]. In other words,
> the client scopes "profile" and "email" will be default client scopes,
> which means that if I don't use "scope=openid" in the OIDC initial
> request, the "profile" and "email" will be ommited from the response as
> well as the ID Token will be ommited from the response.
>
>
> So how to support this on adapters? For Keycloak.js, I can think about
> some variation of existing "update" method like this:
>
>
> keycloak.updateTokenWithScope('service1',
> 5).success(function(accessToken, refreshed) {
>          if (refreshed) {
>              alert("I had existing accessToken for scope 'service1', but
> it needed to be refreshed as it was expired or about to expire in less
> than 5 seconds");
>          } else {
>              alert('I have accessToken for 'service1',  which didn't
> need to be refreshed');
>          }
>          // I can invoke REST service now with the accessToken
>          ...
>      }).error(function() {
>          alert("Failed to refresh the token OR I don't have yet scope
> for 'service1' .");
>          // User usually need to call keycloak.login with the requested
> scope now...
>      });
>
>
>
>
> For servlet adapter something like:
>
> KeycloakSecurityContext ctx = ... // Retrieved from HttpServletRequest
> or Principal as currently
>
> if (ctx.hasScope("service1")) {
>      try {
>          String accessToken = ctx.getScope("service1");
>          // Invoke service1 with accessToken now
>      } catch (TokenRefreshException ex) {
>          log.error("I already had scope for service1, but failed to
> refresh the token. Need to re-login for the scope service1");
>
>          // See method below
>          redirectToKeycloakWithService1Scope();
>      }
> } else {
>      // See method below
>      redirectToKeycloakWithService1Scope();
> }
>
>
> private void redirectToKeycloakWithService1Scope() {
>      KeycloakRedirectUriBuilder builder = ctx.createLoginUrl();
>      URL url = builder.scope("service1").build();
>      httpServletResponse.sendRedirect(url);
> }
>
>
> Regarding the class KeycloakRedirectUriBuilder, I was thinking about
> this class so that servlet adapter are able to easily create login URL
> with custom values for things like scope, prompt, max_age etc. This
> capability is currently missing in servlet adapters and the current
> approach based on parameters forwarding is a bit clunky for few reasons.
> One reason is usability and the other is, that you need to logout first.
>
>
> [1]
>
> https://www.keycloak.org/docs/latest/securing_apps/index.html#javascript-adapter-reference
> [2]
>
> https://www.keycloak.org/docs/latest/securing_apps/index.html#_params_forwarding
> [3] https://issues.jboss.org/browse/KEYCLOAK-8323
>
> Marek
>
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