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Google+ OAuth 2.0 Login#

Overview#

This document will explain how to use Gluu's gplus interception script to configure the Gluu Server to send users to Google for authentication.

Prerequisites#

Configure oxTrust#

Follow the steps below to configure the certificate authentication in the oxTrust Admin GUI.

  1. Navigate to Configuration > Manage Custom Scripts > Person Authentication.

  2. Click the Add Custom Scritp button
    add-script-button

  3. Fill in the form and add the Google External Authenticator Script.

You'll also need to add some custom properties:

  • gplus_client_secrets_file: /etc/gluu/conf/google.json
  • gplus_deployment_type: enroll
  • gplus_remote_attributes_list: email, given_name, family_name, and locale
  • gplus_local_attributes_list: uid, mail, givenName, sn, cn, preferredLanguage
  • gplus_client_secrets_file - It is a mandatory property that holds the path to the application configuration file downloaded from Google console for application. An example is /etc/certs/gplus_client_secrets.json.

Setting Google App#

In order to call Google API's you will need to register as a developer and create client credentials. You can follow these instructions.

The first thing you'll need to do is Create a Project on Google to obtain client credentials. Click "Create project" and enter your desired project name.

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Then click on your newly created project from the listing on the dashboard, and under the Credentials section, create a new "OAuth 2.0 client ID".

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Google will ask you to configure your consent screen, to add your logo and other information displayed to the user to authorize Google to release information.

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Fill out the form...

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Now you're ready to create the credentials. Enter "Authorized JavaScript origins". It should be the uri of your Gluu Server--for example https://idp.example.com.

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Google will display the client-id and secret. Ignore that for now. Instead, download the JSON file which you are going to upload into your Gluu Server next.

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Move this file to the location /etc/gluu/conf/google.json. The JSON file will look something like this example: 

{
  "web": {
    "client_id": "7a64e55f-724d4e8c91823d5f1f18a0b2.apps.googleusercontent.com",
    "auth_uri": "https:\/\/accounts.google.com\/o\/oauth2\/auth",
    "token_uri": "https:\/\/accounts.google.com\/o\/oauth2\/token",
    "auth_provider_x509_cert_url": "https:\/\/www.googleapis.com\/oauth2\/v1\/certs",
    "client_secret": "bb76a2c99be94e35b874",
    "javascript_origins": [
    "https:\/\/brookie.gluu.info"
    ]
  }
}

The last step is to enable Google+ API's:

  • Navigate back to the Google API console
  • Select project and enter project name
  • Open new project "API & auth -> API" menu item in configuration navigation tree
  • Click "Google+ API"
  • Click "Enable API" button

1) gplus_deployment_type - Specify the deployment mode. It is an optional property. If this property isn't specified the script tries to find the user in the local LDAP by 'subject_identifier' claim specified in id_token. If this property has a 'map' value the script allows to map 'subject_identifier' to the local user account. If this property has an 'enroll' value the script adds a new user to the local LDAP with status 'active'. In order to map the IDP attributes to the local attributes it uses properties from both gplus_remote_attributes_list and gplus_local_attributes_list. The allowed values are map and enroll.

2) gplus_remote_attributes_list - Comma-separated list of attribute names (user claims) that Google+ returns which map to local attributes in the gplus_local_attributes_list property. It is mandatory only if gplus_deployment_type is set to 'enroll'.

3) gplus_local_attributes_list - Comma-separated list of Gluu Server LDAP attribute names that are mapped to Google user claims from the gplus_remote_attributes_list property. It is mandatory only if gplus_deployment_type is set to 'enroll'.

4) extension_module - Optional property to specify the full path of an external module that implements two methods:

# This is called when the authentication script initializes

    def init(conf_attr):
    # Code here
    return True/False

# This is called after authentication

    def postLogin(conf_attr, user):
    # Code here
    return True    # or return False

5) gplus_client_configuration_attribute - Optional property to specify the client entry attribute name which can override gplus_client_secrets_file file content. It can be used in cases when all clients should use a separate gplus_client_secrets.json configuration.

Testing#

One simple way to test the configuration is to use oxTrust. In the "Configure Authentication" dropdown menu, select "Google" (or whatever you entered as the "Name" of the custom authentication script--as the default authentication method.

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After you login and logout, you should be presented with a new login form that has the Google login button:

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After clicking the Google login button, you are presented for authorization--Google needs to make sure its ok to release attributes to the Gluu Server:

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If the script doesn't work, and you locked yourself out of oxTrust, don't worry! You could always revert back. Refer to Reverting authentication method

If things go wrong, it can leave the sessions in your browser in a bad state. If things get really weird, remove the cookies in your browser for the hostname of your Gluu Server.