Add Functionality to Verify whether a Given IdP is a Trusted Token Issuer

[dhaura]

Is your feature request related to a problem?

• With the effort on enabling API Based authentication [1], there is a need to check whether a given IdP is a trusted token issuer in order to distinguish between the following modes under federation flows.
  • Mode 1: External IDP is configured in IS and the authentication is handled through IS by redirecting to the external IDP.
  • Mode 2: The app uses the IdP SDK for a social login option, for example, Google; and federating to Google directly from the app.
• Here, Mode 2 flow will be executed, if the IdP is a trusted token issuer.
• Hence, it is necessary to implement a verification mechanism for ascertaining whether the provided IdP is a trusted token issuer.

Describe the solution you would prefer

• Introduce a new method within the IdentityProviderManagementService [2] class that facilitates the verification of a provided IdP as a trusted token issuer.

[1] - #15684
[2] - https://github.com/wso2/carbon-identity-framework/blob/master/components/idp-mgt/org.wso2.carbon.idp.mgt/src/main/java/org/wso2/carbon/idp/mgt/IdentityProviderManagementService.java

[dhaura]

Solution Update

• Since AuthenticationContext object contains the ExternalIdPConfig object, which in turns contains the IdentityProvider object with its relevant IdP properties, there is no need to create a new method within the IdentityProviderManagementService [1] class that facilitates the verification of a provided IdP as a trusted token issuer.
• Therefore, the verification mechanism for ascertaining whether the provided IdP is a trusted token issuer will be done in place at the OpenIDConnectAuthenticator[2] class using the IdP object retrieved through Authentication Context object.

[1] - https://github.com/wso2/carbon-identity-framework/blob/master/components/idp-mgt/org.wso2.carbon.idp.mgt/src/main/java/org/wso2/carbon/idp/mgt/IdentityProviderManagementService.java
[2] - https://github.com/wso2-extensions/identity-outbound-auth-oidc/blob/master/components/org.wso2.carbon.identity.application.authenticator.oidc/src/main/java/org/wso2/carbon/identity/application/authenticator/oidc/OpenIDConnectAuthenticator.java