Access Management 7.3.2

Dynamic OAuth 2.0 authorization

AM can grant OAuth 2.0 scopes statically or dynamically:

Static scopes (default)

OAuth 2.0 client configurations specify the allowed and, optionally, default scopes.

When the client requests allowed scopes and the resource owner consents to grant the client access, AM issues the token with the scopes requested.

When different users use the same client that requests scopes A and B, the access token always includes scopes A and B.

Dynamic scopes

OAuth 2.0 client configurations specify the allowed and, optionally, default scopes.

You configure AM policies for OAuth 2.0 scope decisions. You configure the client or the OAuth 2.0 provider service to use the AM policy engine for scope decisions.

AM checks each scope against the applicable OAuth 2.0 scope policies. AM grants or denies access to scopes dynamically at runtime.

When different users use the same client that requests scopes A and B, the access token scopes can differ.

Example use case

A company supports custom OAuth 2.0 clients for internal applications. The use of the internal applications is bound by the terms and conditions in the contracts of those who work for the company. The terms and conditions grant the internal applications access to profile information the company maintains. It would be redundant to prompt employees and contractors for consent to access their profile information.

The AM administrator creates policies to grant the profile scope for all internal client tokens.

How it works

How policies determine whether to grant or deny an OAuth 2.0 scope
Figure 1. Policies for dynamic scopes

AM processes consent based on the policy decision:

  • If a policy grants access to a scope (GRANT=true), consent is automatic.

    AM does not prompt the user to grant access.

  • If a policy denies access to a scope (GRANT=false), AM omits the scope from any resulting token.

    AM does not prompt the user to grant access.

  • If no policy grants or denies access, then the result depends on the flow.

    When the flow is interactive as in authorization or device code flows, AM prompts the user to grant access or uses the saved consent state if available.

    If the flow is not interactive as in resource owner password or client credentials flows, AM omits the scope from any resulting token.

    For details about which flows are interactive, refer to the examples in OAuth 2.0 grant flows and OpenID Connect grant flows.

The default scopes behavior does not change for dynamic authorization. AM only evaluates default scopes from the OAuth 2.0 client profile when the client does not request a scope. AM follows the same rules to deduce consent for both default and requested scopes.

When issuing refresh tokens, AM issues the same scopes as for the access token, unless a policy explicitly denies one of the scopes.

Validate OAuth 2.0 scope policies

Writing policies for OAuth 2.0 may not be straightforward if your environment requires complex conditions. The easiest way to validate OAuth 2.0 policies is to configure a client to use the policies and request some tokens.

Prepare a demonstration

Start by preparing the demonstration:

OAuth 2.0 scope policy

The sample scope policy denies access to the email scope.

  1. In the AM admin UI, go to Realms > alpha > Authorization > Policy Sets and select Default OAuth2 Scopes Policy Set to edit the policy set.

    This is the oauth2Scopes policy.

  2. Click + Add a Policy, use the following settings, and create the policy:

    Name

    Dynamic OAuth 2.0 Scopes

    Resource Type

    OAuth2 Scope

    Resources

    Select * as the pattern and add email as the scope.

  3. Click the Actions tab, set GRANT to Deny, and save your changes.

  4. Click the Subjects tab, set the subject type to Authenticated Users, and save your changes.

The resulting policy reflects your work:

OAuth 2.0 policy denying the email scope for all authenticated users
Figure 2. OAuth 2.0 scopes policy

OAuth 2.0 client

The OAuth 2.0 client profile in this example overrides the AM OAuth 2.0 provider settings. This lets you test the scope policy without affecting other clients.

  1. Create a confidential OAuth 2.0 client account.

    In the AM admin UI, select Realm > Realm Name > Applications > OAuth 2.0 > Clients > + Add Client, and create a new confidential client with the following settings:

    Client ID

    myClient

    Client Secret

    forgerock

    Redirection URIs

    https://www.example.com:443/callback

    Scopes

    openid
    profile
    email

  2. Add the following settings in the client profile and save your work:

    Core tab > Name

    Dynamic scopes client

    Advanced tab > Grant Types

    Authorization Code
    Client Credentials
    Implicit
    Refresh Token
    Resource Owner Password Credentials

  3. Override OAuth 2.0 provider settings for this client.

    Switch to the OAuth2 Provider Overrides tab, update the following settings and save your work:

    Enable OAuth2 Provider Overrides

    Enabled

    Use Policy Engine for Scope decisions

    Enabled

    Scopes Policy Set

    oauth2Scopes

Resource owner

Create the OAuth 2.0 resource owner account:

  1. In the AM admin UI, select Identities > + Add Identity and fill the required fields.

  2. Record the username and password.

Test the demonstration

Test the feature with non-interactive and interactive flows.

Non-interactive

This test uses the resource owner password credentials flow:

  • The OAuth 2.0 client credentials are myClient:forgerock.

  • The resource owner credentials are the username and password you recorded; here, test:Secret12!.

  • The requested scopes are openid and email.

$ curl \
--request POST \
--user 'myClient:forgerock' \
--data 'scope=openid email' \
--data 'grant_type=password' \
--data 'username=test' \
--data 'password=Secret12!' \
'https://openam.example.com:8443/openam/access_token'
{
  "access_token": "…​",
  "refresh_token": "…​",
  "scope": "openid",
  "id_token": "…​",
  "token_type": "Bearer",
  "expires_in": 3599
}

Notice the access token has "scope": "openid". AM removed email from the scopes.

Interactive

This test uses the implicit flow. It stops after demonstrating the user consent phase of the process.

  1. Update the client configuration to require resource owner consent.

    In the AM admin UI, go to Realm > Realm Name > Applications > OAuth 2.0 > Clients > myClient, switch to the Advanced tab.

    Clear Implied consent and save your change.

  2. In a web browser, go to the /authorize endpoint to initiate the implicit flow.

    https://openam.example.com:8443/openam/authorize?scope=openid+profile+email&response_type=id_token&client_id=myClient&nonce=123&state=456&redirect_uri=https://www.example.com:443/callback

  3. Sign in with the resource owner’s credentials.

  4. Observe the prompt for consent that does not include the email scope:

    AM prompts for consent to access the profile scope.
    Figure 3. Consent for the profile scope