Fixes #28893: Support JWT in UserInfo endpoint response

auth-backends/src/main/scala/bootstrap/rudder/plugin/AuthBackendsConf.scala

@@ -42,6 +42,7 @@ import bootstrap.liftweb.AuthenticationMethods
 import bootstrap.liftweb.RudderConfig
 import bootstrap.liftweb.RudderInMemoryUserDetailsService
 import bootstrap.liftweb.RudderProperties
+import cats.syntax.apply.*
 import com.github.benmanes.caffeine.cache.Caffeine
 import com.normation.errors.IOResult
 import com.normation.plugins.RudderPluginModule
@@ -72,6 +73,7 @@ import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
 import org.springframework.core.ParameterizedTypeReference
 import org.springframework.core.convert.converter.Converter
+import org.springframework.http.MediaType
 import org.springframework.http.RequestEntity
 import org.springframework.http.ResponseEntity
 import org.springframework.security.authentication.AbstractAuthenticationToken
@@ -1050,7 +1052,7 @@ class RudderOidcUserService(
     roleApiMapping:                      RoleApiMapping
 ) extends OidcUserService with RudderUserServerMapping[OidcUserRequest, OidcUser, RudderUserDetail & OidcUser] {
   // we need to use our copy of DefaultOAuth2UserService to log/manage errors
-  super.setOauth2UserService(new RudderDefaultOAuth2UserService()): @unchecked
+  super.setOauth2UserService(new RudderDefaultOAuth2UserService(registrationRepository)): @unchecked
 
   override val protocolId   = RudderOidcUserService.PROTOCOL_ID
   override val protocolName = "OIDC"
@@ -1077,7 +1079,7 @@ class RudderOAuth2UserService(
     roleApiMapping:                      RoleApiMapping
 ) extends OAuth2UserService[OAuth2UserRequest, OAuth2User]
     with RudderUserServerMapping[OAuth2UserRequest, OAuth2User, RudderUserDetail & OAuth2User] {
-  val defaultUserService = new RudderDefaultOAuth2UserService()
+  val defaultUserService = new RudderDefaultOAuth2UserService(registrationRepository)
 
   override val protocolId   = RudderOAuth2UserService.PROTOCOL_ID
   override val protocolName = "OAuth2"
@@ -1130,7 +1132,8 @@ object BuildLogout {
   }
 }
 
-class RudderDefaultOAuth2UserService extends DefaultOAuth2UserService with DebugOAuth2Attributes {
+class RudderDefaultOAuth2UserService(registrationRepository: RudderClientRegistrationRepository)
+    extends DefaultOAuth2UserService with DebugOAuth2Attributes {
 
   /*
    * this is a copy of parent method with more logs/error management
@@ -1147,7 +1150,9 @@ class RudderDefaultOAuth2UserService extends DefaultOAuth2UserService with Debug
   private val requestEntityConverter: Converter[OAuth2UserRequest, RequestEntity[?]] = new OAuth2UserRequestEntityConverter
 
   private val restOperations: RestOperations = {
-    val restTemplate = new RestTemplate
+    val restTemplate = new RestTemplate()
+    // TODO: set message converters instead of intercepting exception ? https://docs.spring.io/spring-framework/reference/web/webmvc/mvc-config/message-converters.html
+    // restTemplate.setMessageConverters(List(JwtConverter(registration.getProviderDetails.getJwkSetUri)).asJava)
     restTemplate.setErrorHandler(new OAuth2ErrorResponseErrorHandler)
     restTemplate
   }
@@ -1205,8 +1210,11 @@ class RudderDefaultOAuth2UserService extends DefaultOAuth2UserService with Debug
       userRequest: OAuth2UserRequest,
       request:     RequestEntity[?]
   ): ResponseEntity[java.util.Map[String, AnyRef]] = {
+    given jwtConfig: Option[JwtConfig] =
+      registrationRepository.registrations.get(userRequest.getClientRegistration.getRegistrationId).map(_.jwtConfig)
+    given ClientRegistration = userRequest.getClientRegistration
     try {
-      return this.restOperations.exchange(request, PARAMETERIZED_RESPONSE_TYPE)
+      this.restOperations.exchange(request, PARAMETERIZED_RESPONSE_TYPE)
     } catch {
       case ex: OAuth2AuthorizationException =>
         var oauth2Error:  OAuth2Error   = ex.getError
@@ -1226,6 +1234,8 @@ class RudderDefaultOAuth2UserService extends DefaultOAuth2UserService with Debug
           null
         )
         throw new OAuth2AuthenticationException(oauth2Error, oauth2Error.toString, ex)
+      case JwtContentTypeException(jwtResponse) =>
+        jwtResponse
       case ex: UnknownContentTypeException  =>
         val errorMessage: String      =
           "An error occurred while attempting to retrieve the UserInfo Resource from '" + userRequest.getClientRegistration.getProviderDetails.getUserInfoEndpoint.getUri + "': response contains invalid content type '" + ex.getContentType.toString + "'. " + "The UserInfo Response should return a JSON object (content type 'application/json') " + "that contains a collection of name and value pairs of the claims about the authenticated End-User. " + "Please ensure the UserInfo Uri in UserInfoEndpoint for Client Registration '" + userRequest.getClientRegistration.getRegistrationId + "' conforms to the UserInfo Endpoint, " + "as defined in OpenID Connect 1.0: 'https://openid.net/specs/openid-connect-core-1_0.html#UserInfo'"
@@ -1565,3 +1575,23 @@ trait DebugOAuth2TokenAttributes extends DebugOAuth2Attributes {
   def pivotAttributeRegistration: RegistrationWithPivotAttribute
   def pivotAttribute:             String = pivotAttributeRegistration.pivotAttributeName
 }
+
+// Special case for JWT interception upon content-type exception in getResponse : signed/encrypted response.
+// Spring has no direct support for these, we need to use Nimbus for decrypting
+object JwtContentTypeException {
+
+  private val APPLICATION_JWT: MediaType = new MediaType("application", "jwt")
+
+  def unapply(
+      ex:                 UnknownContentTypeException
+  )(using
+      jwtConfig:          Option[JwtConfig],
+      clientRegistration: ClientRegistration
+  ): Option[ResponseEntity[util.Map[String, AnyRef]]] = {
+    given JwtConfig = jwtConfig.getOrElse(JwtConfig.default(clientRegistration.getProviderDetails.getJwkSetUri))
+    Option(ex.getResponseHeaders).filter(_ => ex.getContentType.isCompatibleWith(APPLICATION_JWT)) *>
+    decodeJwt(ex.getResponseBodyAsString).toOption
+      .map(jwt => ResponseEntity.ok().body(jwt.getClaims))
+  }
+
+}