OpenID Connect Provider

Presentation

Note

OpenID Connect is a protocol based on REST, OAuth 2.0 and JOSE stacks. It is described here: http://openid.net/connect/.

LL::NG can act as an OpenID Connect Provider (OP). It will reply to OpenID Connect requests to give user identity (through ID Token) and information (through UserInfo endpoint).

As an OP, LL::NG supports many OpenID Connect features:

• Authorization Code, Implicit and Hybrid flows

• Publication of JSON metadata and JWKS data (Discovery)

• prompt, display, ui_locales, max_age parameters

• Mapping custom scope values to non-standard claims

• 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

• Back Channel Logout

• Front Channel Logout

• RP-Initiated 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

• Form Post Response Mode (Since 2.0.16)

Configuration

OpenID Connect Service

See OpenID Connect service configuration chapter.

IssuerDB

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: Rule to allow user to use this module, set to 1 to always allow

Tip

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 exposes its OpenID Connect metadata to help clients configuration.

Metadata can be downloaded at the standard “Well Known” URL: http://auth.example.com/.well-known/openid-configuration

OIDC metadata example:

{
   "end_session_endpoint" : "http://auth.example.com/oauth2/logout",
   "jwks_uri" : "http://auth.example.com/oauth2/jwks",
   "token_endpoint_auth_methods_supported" : [
      "client_secret_post",
      "client_secret_basic"
   ],
   "token_endpoint" : "http://auth.example.com/oauth2/token",
   "response_types_supported" : [
      "code",
      "id_token",
      "id_token token",
      "code id_token",
      "code token",
      "code id_token token"
   ],
   "userinfo_signing_alg_values_supported" : [
      "none",
      "HS256",
      "HS384",
      "HS512",
      "RS256",
      "RS384",
      "RS512"
   ],
   "id_token_signing_alg_values_supported" : [
      "none",
      "HS256",
      "HS384",
      "HS512",
      "RS256",
      "RS384",
      "RS512"
   ],
   "userinfo_endpoint" : "http://auth.example.com/oauth2/userinfo",
   "request_uri_parameter_supported" : "true",
   "acr_values_supported" : [
      "loa-4",
      "loa-1",
      "loa-3",
      "loa-5",
      "loa-2"
   ],
   "request_parameter_supported" : "true",
   "subject_types_supported" : [
      "public"
   ],
   "issuer" : "http://auth.example.com/",
   "grant_types_supported" : [
      "authorization_code",
      "implicit",
      "hybrid"
   ],
   "authorization_endpoint" : "http://auth.example.com/oauth2/authorize",
   "scopes_supported" : [
      "openid",
      "profile",
      "email",
      "address",
      "phone"
   ],
   "require_request_uri_registration" : "false",
   "registration_endpoint" : "http://auth.example.com/oauth2/register"
}

Configuration of Relying Party in LL::NG

Go in Manager and click on OpenID Connect Relying Parties, then click on Add OpenID Relying Party. Set a technical name (without space or special character), like “sample-rp”;

You can then set this RP configuration.

Basic options

• Public client (since version 2.0.4): Set this RP as public client, so authentication is not needed on tokens endpoint. Set this for mobile apps or native Javascript apps.

• Client ID: Client ID for this RP

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

• Allowed redirection addresses for login: Space-separated list of redirect addresses allowed for this RP

Exported attributes (claims)

Changed in version In: 2.0.16, all exported attributes are sent if Always send exported attributes option is enabled in OpenID Connect Service. In previous versions, you had to declare them in Options/Scope/Scope Values content too.

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

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

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

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

• Array: Select how multi-valued attributes are processed

  • Automatic: 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.

Attention

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

Options

• 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.

  • 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

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

  • User attribute: Session field that will be used as main identifier (sub). Default value is whatToTrace.

  • Additional audiences (since version 2.0.8): You can specify a space-separated list of audiences that will be added to the ID Token audiences, and possibly the access token audiences if the access token format is JWT

• Scope

  • Scope values content: see Scope values content below

  • Scope rules: see Scope rules below

• 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 Tokens 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 https://openid.net/specs/openid-connect-core-1_0.html#OfflineAccess 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

• Timeouts

  • Authorization Codes (default: one minute): Expiration time of Authorization Codes, when using the Authorization Code flow.

  • ID Tokens (default: one hour): Expiration time of ID Tokens.

  • Access Tokens (default: one hour): Expiration time of Access Tokens.

  • Offline sessions (default: one month): Lifetime of the refresh token obtained with the offline_access scope. This parameter only applies if offline sessions are enabled.

• Logout

  • Bypass confirm: Bypass logout confirmation when logout is initiated by relaying party

  • Session required: Whether to send the Session ID (sid) in the logout request (Front and Back Channel)

  • Type: Type of logout to perform

  • URL: Specify the relying party’s logout URL

  • 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)

• Comment: set a comment

Macros

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

Display

• Name: Name of the RP application

• Logo: Logo of the RP application

Scope values content

When the Always send exported attributes option is disabled in OpenID Connect Service, attributes can only be released if they are part of a scope.

By default, LL::NG will grant all requested scopes except if Only allow declared scopes option is enabled in OpenID Connect Service.

In this case, only standard OpenID Connect claims are exposed to applications. If you want to add non-standard attributes, you have to create a new scope in the Scope values content section and your application must request that scope.

By default, the following scope-to-attributes are already mapped by LL::NG:

Scope value	Attribute list
profile	name family_name given_name middle_name nickname preferred_username profile picture website gender birthdate zoneinfo locale updated_at
email	email email_verified
address	street_address locality region postal_code country
phone	phone_number phone_number_verified

If you want to expose custom attributes to OpenID Connect clients, you have to declare them in a new scope in this section.

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

• employment_info => position company

In this example, an OpenID Connect client (RP) requesting for the employment_info scope will be able to read the company and position attributes from the UserInfo endpoint.

Important

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

Important

Your custom attributes will only be visible if the application requests the corresponding scope value, or if you use a Scope Rule to always enable that scope.

Scope rules

New in version 2.0.12.

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

By default, LL::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.

Examples:

• 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.

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

The following attributes are made available in the created session:

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

• 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 attributes will be released on the UserInfo endpoint if they are mapped to Exported Attributes and Extra Claims.

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 for selecting 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.

See also

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