OpenID Connect Provider



OpenID Connect is a protocol based on REST, OAuth 2.0 and JOSE stacks. It is described here:

LL::NG can act as an OpenID Connect Provider (OP). It will answer to OpenID Connect requests to give user identity (through ID Token) and information (through User Info end point).

As an OP, LL::NG supports a lot of OpenID Connect features:

  • Authorization Code, Implicit and Hybrid flows

  • Publication of JSON metadata and JWKS data (Discovery)

  • prompt, display, ui_locales, max_age parameters

  • Extra claims definition

  • Authentication context Class References (ACR)

  • Nonce

  • Dynamic registration

  • Access Token Hash generation

  • ID Token signature (HS256/HS384/HS512/RS256/RS384/RS512)

  • UserInfo endpoint, as JSON or as JWT

  • Request and Request URI

  • Session management

  • FrontChannel Logout

  • BackChannel Logout

  • PKCE (Since 2.0.4) - See RFC 7636

  • Introspection endpoint (Since 2.0.6) - See RFC 7662

  • Offline access (Since 2.0.7)

  • Refresh Tokens (Since 2.0.7)

  • Optional JWT Access Tokens (Since 2.0.12) - See RFC 9068


OpenID Connect Service

See OpenID Connect service configuration chapter.


Go in General Parameters » Issuer modules » OpenID Connect and configure:

  • Activation: set to On.

  • Path: keep ^/oauth2/ unless you need to use another path

  • Use rule: a rule to allow user to use this module, set to 1 to always allow.


For example, to allow only users with a strong authentication level:

$authenticationLevel > 2

Configuration of LL::NG in Relying Party

Each Relying Party has its own configuration way. LL::NG publish its OpenID Connect metadata to ease the configuration of client.

The metadata can be found at the standard “Well Known” URL:

An example of its content:

   "end_session_endpoint" : "",
   "jwks_uri" : "",
   "token_endpoint_auth_methods_supported" : [
   "token_endpoint" : "",
   "response_types_supported" : [
      "id_token token",
      "code id_token",
      "code token",
      "code id_token token"
   "userinfo_signing_alg_values_supported" : [
   "id_token_signing_alg_values_supported" : [
   "userinfo_endpoint" : "",
   "request_uri_parameter_supported" : "true",
   "acr_values_supported" : [
   "request_parameter_supported" : "true",
   "subject_types_supported" : [
   "issuer" : "",
   "grant_types_supported" : [
   "authorization_endpoint" : "",
   "scopes_supported" : [
   "require_request_uri_registration" : "false",
   "registration_endpoint" : ""

Configuration of Relying Party in LL::NG

Go in Manager and click on OpenID Connect Relying Parties, then click on Add OpenID Relying Party. Give a technical label (no spaces, no special characters), like “sample-rp”;

You can then access to the configuration of this RP.

Exported attributes


By default, only standard OpenID Connect claims are visible to applications. If you want to add non-standard attributes, you must create a new scope in the Scope values content section and make your application request it

For each OpenID Connect attribute you want to release to applications, you can define:

  • Claim name: the name of the attribute as it will appear in Userinfo responses

  • Variable name: the name of the LemonLDAP::NG session variable containing the attribute value

  • Type: the data type of the attribute. By default, a string. Choosing integer or boolean will make the attribute appear as the corresponding JSON type.

  • Array: choose how to process multi-valued attributes

    • Auto: If the session key contains a single value, it will be released as a JSON number, string or boolean, depending on the previously specified type. If the session key contains multiple values, it will be released as an array of numbers, strings or booleans.

    • Always: Return an array even if the attribute only contains one value

    • Never: If the session key contains a single value, it will be released as a JSON number, string or boolean. If the session key contains multiple values, it will be released as a single string with a separator character.


The specific sub attribute is not defined here, but in User attribute parameter (see below).

Scope values content

By default, LemonLDAP::NG already defines the following scope-to-attribute map:

Scope value

Attribute list


name family_name given_name middle_name nickname preferred_username profile picture website gender birthdate zoneinfo locale updated_at


email email_verified


street_address locality region postal_code country


phone_number phone_number_verified

If you want to make custom attribute visible to OpenID Connect clients, you need to declare them in a new scope in this section.

Add your additional scope as the Key, and a space-separated list of attribute as the Value:

  • employment_info => position company

In this example, an OpenID Client asking for the employment_info scope will be able to read the company and position attribute from the Userinfo endpoint.


Any attribute defined in this section must be mapped to a LemonLDAP::NG session variable in the Exported Attributes section


Your custom attributes will only be visible if the application requests the corresponding scope value

Scope Rules

New in version 2.0.12.

beta This feature may change in a future version in a way that breaks compatibility with existing configuration

By default, LemonLDAP::NG grants all scopes requested by the application, as long as the user consents to them.

This configuration screen allows you to change that behavior by attaching a rule to a particular scope.

  • If the rule evaluates to true, the scope is added to the current request, even if it was not requested by the application

  • If the rule evaluates to false, the scope is removed from the current request

  • Scopes which are not declared in the “Scope rules” list are left untouched

When writing scope rules, you can use the special $requested variable. This variables evaluates to true within a scope rule when the corresponding scope has been requested by the application. You can use this variable in a dynamic rule when you only want to add a scope when the application requested it.


  • read: inGroup('readers')

    • the read scope will be granted if the user is a member of the readers group even if the application did not request it.

  • write: $requested and inGroup('writers')

    • the write scope will be granted if the user is a member of the writers group, but only if the application requested it.


  • Basic

    • Client ID: Client ID for this RP

    • Client secret: Client secret for this RP (can be use for symmetric signature)

    • Public client (since version 2.0.4): set this RP as public client, so authentication is not needed on token endpoint

    • Redirection addresses: Space separated list of redirect addresses allowed for this RP

  • Advanced

    • Bypass consent: Enable if you never want to display the scope sharing consent screen (consent will be accepted by default). Bypassing the consent is not compliant with OpenID Connect standard.

    • User attribute: session field that will be used as main identifier (sub)

    • Force claims to be returned in ID Token: This options will make user attributes from the requested scope appear as ID Token claims.

    • Use JWT format for Access Token (since version 2.0.12): When using this option, Access Tokens will use the JWT format, which means they can be verified by external OAuth2.0 resource servers without using the introspection or userinfo endpoint.

    • Release claims in Access Token (since version 2.0.12): If Access Tokens are in JWT format, this option lets you release the claims defined in the Extra Claims section inside the Access Token itself.

    • Additional audiences (since version 2.0.8): You can specify a space-separate list of audiences that will be added the audiences of the ID Token

    • Use refresh tokens (since version 2.0.7): If this option is set, LemonLDAP::NG will issue a Refresh Token that can be used to obtain new access tokens as long as the user session is still valid.

  • Timeouts

    • Authorization Code expiration: Expiration time of authorization code, when using the Authorization Code flow. The default value is one minute.

    • ID Token expiration: Expiration time of ID Tokens. The default value is one hour.

    • Access token expiration: Expiration time of Access Tokens. The default value is one hour.

    • Offline session expiration: This sets the lifetime of the refresh token obtained with the offline_access scope. The default value is one month. This parameter only applies if offline sessions are enabled.

  • Security

    • ID Token signature algorithm: Select one of the available public key (RSXXX) or HMAC (HSXXX) based signature algorithms

    • Access Token signature algorithm (since version 2.0.12): Select one of the available public key signature algorithms

    • Userinfo response format (since version 2.0.12): By default, UserInfo is returned as a simple JSON object. You can also choose to return it as a JWT, using one of the available signature algorithms.

    • Require PKCE (since version 2.0.4): a code challenge is required at token endpoint (see RFC 7636)

    • Allow offline access (since version 2.0.7): After enabling this feature, an application may request the offline_access scope, and will obtain a Refresh Token that persists even after the user has logged off. See for details. These offline sessions can be administered through the Session Browser.

    • Allow OAuth2.0 Password Grant (since version 2.0.8): Allow the use of the Resource Owner Password Credentials Grant by this client. This feature only works if you have configured a form-based authentication module.

    • Allow OAuth2.0 Client Credentials Grant (since version 2.0.11): Allow the use of the Client Credentials Grant by this client.

    • Authentication Level: required authentication level to access this application

    • Access Rule: lets you specify a Perl rule to restrict access to this client

  • Logout

    • Allowed redirection addresses for logout: A space separated list of URLs that this client can redirect the user to once the logout is done (through post_logout_redirect_uri)

    • URL: Specify the relying party’s logout URL

    • Type: Type of Logout to perform (only Front-Channel is implemented for now)

    • Session required: Whether to send the Session ID in the logout request

Access Rule extra variables

When writing your access rules, you can additionally use the following variables:

  • $_oidc_grant_type (since version 2.0.14): the grant type being used to access this service. Possible values: authorizationcode, implicit, hybrid, clientcredentials, password

Resource Owner Password Credentials Grant

The Resource Owner Password Credentials Grant allows you to exchange a user’s login and password for an access token. This must be considered a legacy form of authentication, since the Authorization Code web-based flow is prefered for all applications that support it. It can however be useful in some scenarios involving technical accounts that cannot implement a web-based authentication flow.

Changed in version 2.0.12: when using the Choice authentication module, the Choice used for password authentication setting can be used to select which authentication choice is used by the Resource Owner Password Credentials Grant. Naturally, the selected choice must be a password-based authentication method (LDAP, DBI, REST, etc.)

See also

Specification for the Resource Owner Password Credentials Grant: RFC 6749#section-4.3

Client Credentials Grant

The Client Credentials Grant allows you to obtain an Access Token using only a Relying Party’s Client ID and Client Secret.

The following attributes are made available in the created session:

  • The _whatToTrace attribute (main session identifier), is set to the relying party’s configuration key

  • The _scope attribute is set to the requested scopes

  • The _clientId attribute is set to the Client ID that obtained the access token.

  • The _clientConfKey attribute is set to the LemonLDAP::NG configuration key for the client that obtained the access token.

The Access Rule, if defined, will have access to those variables, as well as the @ENV array. You can use it to restrict the use of this grant to pre-determined scopes, a particular IP address, etc.

These session attribute will be released on the UserInfo endpoint if they are mapped to Exported Attributes and Extra Claims

See also

Specification for the Client Credentials Grant: RFC 6749#section-4.4


You can define here macros that will be only evaluated for this service, and not registered in the session of the user.


  • Display name: Name of the RP application

  • Logo: Logo of the RP application