Nextcloud OIDC Login

Make possible create users and login via one single OpenID Connect provider. Even though a fork of nextcloud-social-login, it fundamentally differs in two ways - aims for simplistic, single provider login (and hence is very minimalastic), and it supports having LDAP as the primary user backend. This way, you can use OpenID Connect to login to Nextcloud while maintaining an LDAP backend with attributes with the LDAP plugin. Supports automatic discovery of endpoints through the OpenID Connect spec, with a single provider configuration attribute.

Config

All configuration for the app is directly picked up from Nextcloud's system configuration file (config.php). The following properties (with their descriptions) are valid configuration entries.

$CONFIG = array (
    // Some Nextcloud options that might make sense here
    'allow_user_to_change_display_name' => false,
    'lost_password_link' => 'disabled',

    // URL of provider. All other URLs are auto-discovered from .well-known
    'oidc_login_provider_url' => 'https://openid.example.com',

    // Client ID and secret registered with the provider
    'oidc_login_client_id' => 'application',
    'oidc_login_client_secret' => 'secret',

    // Automatically redirect the login page to the provider
    'oidc_login_auto_redirect' => false,

    // Redirect to this page after logging out the user
    'oidc_login_logout_url' => 'https://openid.example.com/thankyou',

    // Quota to assign if no quota is specified in the OIDC response (bytes)
    'oidc_login_default_quota' => '1000000000',

    // Login button text
    'oidc_login_button_text' => 'Log in with OpenID',

    // Attribute map for OIDC response. Available keys are:
    //   i)   id:       Unique identifier for username
    //   ii)  name:     Full name
    //   iii) mail:     Email address
    //   iv)  quota:    Nextcloud storage quota
    //   v)   home:     Home directory location. A symlink or external storage to this location is used
    //   vi)  ldap_uid: LDAP uid to search for when running in proxy mode
    //   vii) groups:   Array or space separated string of NC groups for the user
    //
    // The attributes in the OIDC response are flattened by adding the nested
    // array key as the prefix and an underscore. Thus,
    //
    //     $profile = [
    //         'id' => 1234,
    //         'attributes' => [
    //             'uid' => 'myuid'
    //         ]
    //     ];
    //
    // would become,
    //
    //     $profile = [
    //         'id' => 1234,
    //         'attributes_uid' => 'myuid'
    //     ]
    //
    'oidc_login_attributes' => array (
        'id' => 'sub',
        'name' => 'name',
        'mail' => 'email',
        'quota' => 'ownCloudQuota',
        'home' => 'homeDirectory',
        'ldap_uid' => 'uid',
        'groups' => 'ownCloudGroups',
    ),

    // Default group to add users to (optional, defaults to nothing)
    'oidc_login_default_group' => 'oidc',

    // Use external storage instead of a symlink to the home directory
    // Requires the files_external app to be enabled
    'oidc_login_use_external_storage' => false,

    // Set OpenID Connect scope
    'oidc_login_scope' => 'openid profile',

    // Run in LDAP proxy mode
    // In this mode, instead of creating users of its own, OIDC login
    // will get the existing user from an LDAP database and only
    // perform authentication with OIDC. All user data will be derived
    // from the LDAP database instead of the OIDC user response
    //
    // The `id` attribute in `oidc_login_attributes` must return the
    // "Internal Username" (see expert settings in LDAP integration)
    'oidc_login_proxy_ldap' => false,

    // Disable creation of new users from OIDC login
    'oidc_login_disable_registration' => true,

    // Fallback to direct login if login from OIDC fails
    // Note that no error message will be displayed if enabled
    'oidc_login_redir_fallback' => false,

    // Use an alternative login page
    // This page will be php-included instead of a redirect if specified
    // In the example below, the PHP file `login.php` in `assets`
    // in nextcloud base directory will be included
    // Note: the PHP variable $OIDC_LOGIN_URL is available for redirect URI
    // Note: you may want to try setting `oidc_login_logout_url` to your
    // base URL if you face issues regarding re-login after logout
    'oidc_login_alt_login_page' => 'assets/login.php',
    
    // For development, you may disable TLS verification. Default value is `true`
    // which should be kept in production
    'oidc_login_tls_verify' => true,
);

Usage with Keycloak

1. Create a new Client for Nextcloud in a Keycloak Realm of your choosing.

   1. Set a Client ID and save.
   2. Set Access type to confidential
   3. Add a Valid Redirect URI e.g. https://cloud.example.com/*.
   4. Open the Fine Grain OpenID Connect Configuration dropdown and set ID Token Signature Algorithm to RS256 and save.

2. Open your created Client and go to Mappers. (optional)

   1. Click create and set Mapper Type to User Attribute.
   2. Set Name, User Attribute, and Token Claim Name to ownCloudQuota.
   3. Set Claim JSON Type as String.
   4. Click create and set Mapper Type to User Client Role.
   5. Set Name and Token Claim Name to ownCloudGroups and select your Client ID.
   6. Set Claim JSON Type as String.
   7. Add or edit a User and go to Attributes.
   8. Add an Attribute by setting Key as ownCloudQuota and Value to your preferred limit (in bytes).

3. Necessary config.php settings (differing from above)

'oidc_login_client_id' => 'nextcloud', // Client ID: Step 1
'oidc_login_client_secret' => 'secret', // Client Secret: Got to Clients -> Client -> Credentials
'oidc_login_provider_url' => 'https://keycloak.example.com/auth/realms/YOUR_REALM',
'oidc_login_logout_url' => 'https://keycloak.example.com/auth/realms/MY_REALM/protocol/openid-connect/logout?redirect_uri=https%3A%2F%2Fcloud.example.com%2F',
'oidc_login_auto_redirect' => true,
'oidc_login_redir_fallback' => true,
'oidc_login_attributes' => array(
	'id' => 'preferred_username',
	'mail' => 'email',
),
// If you are running Nextcloud behind a reverse proxy, make sure this is set
'overwriteprotocol' => 'https',

Note:

• If necessary, restart Nextcloud to clear the APCu cache for the config file.
• You can use the above Mapper method to map any arbitrary user attribute in Keycloak to output with standard userdata, allowing use of arbitrary fields for id, etc.