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Logout from Gluu Server#

OpenID Connect Single Log Out (SLO)#

The Gluu Server uses OpenID Connect to end sessions for logout. Usually a logout link is provided to the connected SP and the session is killed inside the IDP.

When using OpenID Connect Logout, it is recommeneded to use Front-Channel Logout. In Front-Channel Logout the browser receives a page with a list of application logout urls within an iframe. This prompts the browser to call each application logout individually and the OpenID Connect end-session endpoint via Javascript.

The workflow for single logout for two applications using OpenID Connect Front-Channel Logout would be the following:

  1. App-A - registers frontchannel_logout_uri_1
  2. App-B - registers frontchannel_logout_uri_2
  3. App-A - login to the Authorization Server (AS), in this case the Gluu Server.
  4. App-B - login to AS (SSO)
  5. App-A - calls /end_session
  6. AS - returns back HTML with iframes where each iframe points to all frontchannel_logout_uris within this session, in our case it is frontchannel_logout_uri_1 and frontchannel_logout_uri_2
  7. Browser loads HTML (with all iframes, so it calls frontchannel_logout_uri_1 and frontchannel_logout_uri_2)
  8. App-A does not know anything about frontchannel_logout_uri_2, it just calls /end_session endpoint and it's the responsibility of the AS to track it and return the correct HTML page with iframes (once iframe is loaded, it means that frontchannel_logout_uri_2 is called and app-B must log itself out).

There are a few important points to note:

  1. post_logout_redirect_uri is not mandatory but registration specification says The value MUST have been previously registered with the OP. We have dual behavior description directly in specification. oxauth ends session successfully (if session is present on OP) independently from whether post_logout_redirect_uri is valid or not. If it is not valid then server returns 200 with message Session is ended successfully but redirect to post logout redirect uri is not performed because it fails validation. Server returns 200 because session was ended successfully however inform that validation failed.
  2. id_token_hint and session_id parameters are optional. Therefore OP will end session successfully if these parameters are missed. However from other side if RP included them in request OP validates them and if any of those are invalid OP returns 400 (Bad Request) http code.

Read the OpenID Connect Front-Channel Logout Specifications to learn more about logout with OpenID Connect.

SAML Logout#

The Shibboleth IDP (which is included in the Gluu Server) does not support single logout in any meaningful sense. Take a look at the Shibboleth wiki for more information.

Instead, the logout has to be initiated from the SP. The logout URL is a combination of the SP logout link (i.e. for the Shibboleth SP, https://[SP_hostname]/Shibboleth.sso/Logout) and the Gluu Server SAML Logout link (https://[Gluu_Server_hostname]/idp/Authn/oxAuth/logout).

Sending the above combination will kill the sessions from both the SP and the Gluu Server.

Click the picture below to see a video example of the process in action:

Link to SAML Logout video

Customizing Logout#

It is possible to use a custom authentication script to call individual logout methods for both SAML and OpenID Connect and log out of the desired SP/RPs when the user logs out of the Gluu Server. Please see the Custom Script Guide to start writing your own custom scripts.