user_oidc

OpenID Connect user backend for Nextcloud

General usage

See Nextcloud and OpenID-Connect for a proper jumpstart.

User IDs

The OpenID Connect backend will ensure that user ids are unique even when multiple providers would report the same user id to ensure that a user cannot identify for the same Nextcloud account through different providers. Therefore, a hash of the provider id and the user id is used. This behaviour can be turned off in the provider options.

Commandline settings

The app could also be configured by commandline.

Provider entries

Providers are located by provider identifier.

To list all configured providers, use:

sudo -u www-data php /var/www/nextcloud/occ user_oidc:provider

To show detailed provider configuration, use:

sudo -u www-data php /var/www/nextcloud/occ user_oidc:provider demoprovider

A provider is created if none with the given identifier exists and all parameters are given:

sudo -u www-data php /var/www/nextcloud/occ user_oidc:provider demoprovider --clientid="WBXCa003871" \
    --clientsecret="lbXy***********" --discoveryuri="https://accounts.example.com/openid-configuration"

Attribute mappings can be optionally specified. For more details refer to occ user_oidc:provider --help.

To delete a provider, use:

sudo -u www-data php /var/www/nextcloud/occ user_oidc:provider:delete demoprovider
  Are you sure you want to delete OpenID Provider demoprovider
  and may invalidate all assiciated user accounts.

To skip the confirmation, use --force.

Warning: be careful with the deletion of a provider because in some setup, this invalidates access to all NextCloud accounts associated with this provider.

Avatar support

The avatar attribute on your IdP side may contain a URL pointing to an image file or directly a base64 encoded image. The base64 should start with data:image/png;base64, or data:image/jpeg;base64,. The image should be in JPG or PNG format and have the same width and height.

Disable default claims

Even if you don't map any attribute for quota, display name, email or groups, this application will ask for the 'quota', 'name', 'email', 'groups' claims and map them to an attribute with the same name.

To change this behaviour and disable the default claims, you can change this value in config.php:

'user_oidc' => [
    'enable_default_claims' => false,
],

When default claims are disabled, each claim will be asked for only if there is an attribute explicitely mapped in the OpenId client settings (in Nextcloud's admin settings).

ID4me option

ID4me is an application setting switch which is configurable as normal Nextcloud app setting:

sudo -u www-data php /var/www/nextcloud/occ config:app:set --value=1 user_oidc id4me_enabled

Disable other login methods

If there is only one OpenID Connect provider configured, it can be made the default login method and the user would get redirected to the provider immediately for the login. Admins can still use the regular login through adding the ?direct=1 parameter to the login URL.

sudo -u www-data php var/www/nextcloud/occ config:app:set --value=0 user_oidc allow_multiple_user_backends

PKCE

This app supports PKCE (Proof Key for Code Exchange). https://datatracker.ietf.org/doc/html/rfc7636 Unless PKCE is not supported by the configured OpenID Connect provider, it is enabled by default. You can also manually disable it in config.php:

'user_oidc' => [
    'use_pkce' => false,
],

Single logout

Single logout is enabled by default. When logging out of Nextcloud, the end_session_endpoint of the OpenID Connect provider is requested to end the session on this side.

It can be disabled in config.php:

'user_oidc' => [
    'single_logout' => false,
],

Backchannel logout

OpenId backchannel logout is supported by this app. You just have to configure 2 settings for the OpenId client (on the provider side, Keycloak for example):

1. Backchannel Logout URL: If your Nextcloud base URL is https://my.nextcloud.org and your OpenId provider identifier (on the Nextcloud side) is "myOidcProvider" set the backchannel Logout URL to https://my.nextcloud.org/index.php/apps/user_oidc/backchannel-logout/myOidcProvider . This URL is provided for each provider in the OpenID Connect admin settings.
2. Enable the "Backchannel Logout Session Required" setting.

Auto provisioning

By default, this app provisions the users with the information contained in the OIDC token which means it gets the user information (such as the display name or the email) from the ID provider. This also means that user_oidc takes care of creating the users when they first log in.

It is possible to disable auto provisioning to let other user backends (like LDAP) take care of user creation and attribute mapping. This leaves user_oidc to only take care of authentication.

Auto provisioning can be disabled in config.php:

'user_oidc' => [
    'auto_provision' => false,
],

⚠️ When relying on the LDAP user backend for user provisioning, you need to adjust the "Login Attributes" section and the Expert tab's "Internal Username" value of your LDAP settings. Even if LDAP does not handle the login process, the user_oidc app will trigger an LDAP search when logging in to make sure the user is created if it was not synced already. So it is essential that:

• the OpenID Connect "User ID mapping" attribute matches the LDAP Expert tab's "Internal Username". The attribute names can be different but their values should match. Do not change the LDAP configuration, simply adapt the OpenID Connect provider configuration.
• the OpenID Connect "User ID mapping" attribute can be used in the LDAP login query defined in the "Login Attributes" tab.

In other words, make sure that your OpenID Connect provider's "User ID mapping" setting is set to an attribute which provides the same values as the LDAP attribute set in "Internal Username" in your LDAP settings.

Soft auto provisioning

If you have existing users managed by another backend (local or LDAP users for example) and you want them to be managed by user_oidc but you still want user_oidc to auto-provision users (create new users when they are in the Oidc IdP but not found in any other user backend), this is possible with soft auto provisioning.

There is a soft_auto_provision system config flag that is enabled by default and is effective only if auto_provision is enabled.

'user_oidc' => [
    'auto_provision' => true, // default: true
    'soft_auto_provision' => true, // default: true
],

• When soft_auto_provision is enabled
  • If the user already exists in another backend, we don't create a new one in the user_oidc backend. We update the information (mapped attributes) of the existing user. If the user does not exist in another backend, we create it in the user_oidc backend
• When soft_auto_provision is disabled
  • We refuse Oidc login of users that already exist in other backends

Soft auto provisioning without user creation

You might want soft auto provisioning but prevent user_oidc to create users, meaning you want user_oidc to accept connection only for users that already exist in Nextcloud and are managed by other user backend BUT you still want user_oidc to set the user information according to the OIDC mapped attributes.

For that, there is a disable_account_creation system config flag that is false by default and is effective only if auto_provision and soft_auto_provision are enabled is enabled.

'user_oidc' => [
    'auto_provision' => true, // default: true
    'soft_auto_provision' => true, // default: true
    'disable_account_creation' => true, // default: false
],

4 Provisioning scenarios

• Create users if they don't exist
  • Accept connection of existing users (from other backends) and update their attributes:

    'user_oidc' => [
        'auto_provision' => true, // default: true
        'soft_auto_provision' => true, // default: true
    ],

  • Do not accept connection of users existing in other backends:

    'user_oidc' => [
        'auto_provision' => true, // default: true
        'soft_auto_provision' => false, // default: true
    ],

• Do not create users if they don't exist
  • Update attributes of existing users (create by user_oidc or any other backend):

    'user_oidc' => [
    	'auto_provision' => true, // default: true
    	'soft_auto_provision' => true, // default: true
    	'disable_account_creation' => true, // default: false
    ],

  • Do not update attributes of existing users:

    'user_oidc' => [
        'auto_provision' => false, // default: true
    ],

Pre-provisioning

If you need the users to exist before they authenticate for the first time (because you want other users to be able to share files with them, for example) you can pre-provision them with the user_oidc API:

curl -H "ocs-apirequest: true" -u admin:admin -X POST -H "content-type: application/json" \
  -d '{"providerId":2,"userId":"new_user","displayName":"New User","email":"[email protected]","quota":"5GB"}' \
  https://my.nextcloud.org/ocs/v2.php/apps/user_oidc/api/v1/user

Only the providerId and userId parameters are mandatory.

You can also delete users managed by user_oidc with this API endpoint:

curl -H "ocs-apirequest: true" -u admin:admin -X DELETE
  https://my.nextcloud.org/ocs/v2.php/apps/user_oidc/api/v1/user/USER_ID

UserInfo request for Bearer token validation

The OIDC tokens used to make API call to Nextcloud might have been generated by an external entity. It is possible that they don't contain the user ID attribute. In this case, this attribute can be requested to the provider's userinfo endpoint.

Add this to config.php to enable such extra validation step:

'user_oidc' => [
    'userinfo_bearer_validation' => true,
],

If you only want the token to be validated against the userinfo endpoint, it is possible to disable the classic "self-encoded" validation:

'user_oidc' => [
    'userinfo_bearer_validation' => true,
    'selfencoded_bearer_validation' => false,
],

Disable audience and azp checks

The audience and azp token claims will be checked when validating a login or bearer ID token. You can disable these check with these config value (in config.php):

'user_oidc' => [
    'login_validation_audience_check' => false,
    'login_validation_azp_check' => false,
    'selfencoded_bearer_validation_audience_check' => false,
    'selfencoded_bearer_validation_azp_check' => false,
],

Disable the user search by email

This app can stop matching users (when a user search is performed in Nextcloud) by setting this config.php value:

'user_oidc' => [
    'user_search_match_emails' => false,
],

Building the app

Requirements for building:

• Node.js 14
• NPM 7
• PHP
• composer

The app uses krankerl to build the release archive from the git repository. The release will be put into build/artifacts/ when running the krankerl package.

The app can also be built without krankerl by manually running:

composer install --no-dev -o
npm ci
npm run build

On Ubuntu 20.04, a possible way to get build working is with matching npm and node versions is:

sudo apt-get remove nodejs
sudo curl -sL https://deb.nodesource.com/setup_14.x | sudo -E bash -
sudo apt-get install nodejs
sudo npm install -g npm@7