/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates
 * and other contributors as indicated by the @author tags.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.keycloak.protocol.oidc.endpoints;

import org.jboss.logging.Logger;
import org.keycloak.http.HttpRequest;
import org.keycloak.http.HttpResponse;
import org.keycloak.OAuth2Constants;
import org.keycloak.OAuthErrorException;
import org.keycloak.authentication.AuthenticationProcessor;
import org.keycloak.authorization.AuthorizationProvider;
import org.keycloak.authorization.authorization.AuthorizationTokenService;
import org.keycloak.authorization.util.Tokens;
import org.keycloak.common.ClientConnection;
import org.keycloak.common.Profile;
import org.keycloak.common.VerificationException;
import org.keycloak.common.constants.ServiceAccountConstants;
import org.keycloak.common.util.KeycloakUriBuilder;
import org.keycloak.common.util.ResponseSessionTask;
import org.keycloak.constants.AdapterConstants;
import org.keycloak.events.Details;
import org.keycloak.events.Errors;
import org.keycloak.events.EventBuilder;
import org.keycloak.events.EventType;
import org.keycloak.jose.jws.JWSInput;
import org.keycloak.jose.jws.JWSInputException;
import org.keycloak.models.AuthenticatedClientSessionModel;
import org.keycloak.models.AuthenticationFlowModel;
import org.keycloak.models.ClientModel;
import org.keycloak.models.ClientScopeModel;
import org.keycloak.models.ClientSessionContext;
import org.keycloak.models.KeycloakSession;
import org.keycloak.models.RealmModel;
import org.keycloak.models.UserModel;
import org.keycloak.models.UserSessionModel;
import org.keycloak.models.utils.AuthenticationFlowResolver;
import org.keycloak.models.utils.KeycloakModelUtils;
import org.keycloak.protocol.oidc.OIDCAdvancedConfigWrapper;
import org.keycloak.protocol.oidc.OIDCLoginProtocol;
import org.keycloak.protocol.oidc.TokenExchangeContext;
import org.keycloak.protocol.oidc.TokenExchangeProvider;
import org.keycloak.protocol.oidc.TokenManager;
import org.keycloak.protocol.oidc.grants.ciba.CibaGrantType;
import org.keycloak.protocol.oidc.grants.device.DeviceGrantType;
import org.keycloak.protocol.oidc.utils.AuthorizeClientUtil;
import org.keycloak.protocol.oidc.utils.OAuth2Code;
import org.keycloak.protocol.oidc.utils.OAuth2CodeParser;
import org.keycloak.protocol.oidc.utils.PkceUtils;
import org.keycloak.protocol.saml.JaxrsSAML2BindingBuilder;
import org.keycloak.protocol.saml.SamlClient;
import org.keycloak.protocol.saml.SamlProtocol;
import org.keycloak.rar.AuthorizationRequestContext;
import org.keycloak.representations.AccessToken;
import org.keycloak.representations.AccessTokenResponse;
import org.keycloak.representations.dpop.DPoP;
import org.keycloak.representations.idm.authorization.AuthorizationRequest.Metadata;
import org.keycloak.saml.common.constants.JBossSAMLConstants;
import org.keycloak.saml.common.constants.JBossSAMLURIConstants;
import org.keycloak.saml.common.exceptions.ConfigurationException;
import org.keycloak.saml.common.exceptions.ProcessingException;
import org.keycloak.saml.common.util.DocumentUtil;
import org.keycloak.services.CorsErrorResponseException;
import org.keycloak.services.ServicesLogger;
import org.keycloak.services.Urls;
import org.keycloak.services.clientpolicy.ClientPolicyContext;
import org.keycloak.services.clientpolicy.ClientPolicyException;
import org.keycloak.services.clientpolicy.context.ResourceOwnerPasswordCredentialsContext;
import org.keycloak.services.clientpolicy.context.ResourceOwnerPasswordCredentialsResponseContext;
import org.keycloak.services.clientpolicy.context.ServiceAccountTokenRequestContext;
import org.keycloak.services.clientpolicy.context.ServiceAccountTokenResponseContext;
import org.keycloak.services.clientpolicy.context.TokenRefreshContext;
import org.keycloak.services.clientpolicy.context.TokenRefreshResponseContext;
import org.keycloak.services.clientpolicy.context.TokenRequestContext;
import org.keycloak.services.clientpolicy.context.TokenResponseContext;
import org.keycloak.services.managers.AppAuthManager;
import org.keycloak.services.managers.AuthenticationManager;
import org.keycloak.services.managers.AuthenticationSessionManager;
import org.keycloak.services.managers.ClientManager;
import org.keycloak.services.managers.RealmManager;
import org.keycloak.services.managers.UserSessionManager;
import org.keycloak.services.resources.Cors;
import org.keycloak.services.util.AuthorizationContextUtil;
import org.keycloak.services.util.DefaultClientSessionContext;
import org.keycloak.services.util.DPoPUtil;
import org.keycloak.services.util.MtlsHoKTokenUtil;
import org.keycloak.sessions.AuthenticationSessionModel;
import org.keycloak.sessions.RootAuthenticationSessionModel;
import org.keycloak.util.TokenUtil;
import org.keycloak.utils.ProfileHelper;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.InternalServerErrorException;
import jakarta.ws.rs.OPTIONS;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.HttpHeaders;
import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.core.MultivaluedHashMap;
import jakarta.ws.rs.core.MultivaluedMap;
import jakarta.ws.rs.core.Response;
import jakarta.ws.rs.core.Response.Status;
import javax.xml.namespace.QName;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Stream;

import static org.keycloak.utils.LockObjectsForModification.lockUserSessionsForModification;

/**
 * @author <a href="mailto:sthorger@redhat.com">Stian Thorgersen</a>
 */
public class TokenEndpoint {

    private static final Logger logger = Logger.getLogger(TokenEndpoint.class);
    private MultivaluedMap<String, String> formParams;
    private ClientModel client;
    private Map<String, String> clientAuthAttributes;
    private OIDCAdvancedConfigWrapper clientConfig;
    private DPoP dPoP;

    private enum Action {
        AUTHORIZATION_CODE, REFRESH_TOKEN, PASSWORD, CLIENT_CREDENTIALS, TOKEN_EXCHANGE, PERMISSION, OAUTH2_DEVICE_CODE, CIBA
    }

    private final KeycloakSession session;

    private final HttpRequest request;

    private final HttpResponse httpResponse;

    private final HttpHeaders headers;

    private final ClientConnection clientConnection;

    private final TokenManager tokenManager;
    private final RealmModel realm;
    private final EventBuilder event;

    private Action action;

    private String grantType;

    private Cors cors;

    public TokenEndpoint(KeycloakSession session, TokenManager tokenManager, EventBuilder event) {
        this.session = session;
        this.clientConnection = session.getContext().getConnection();
        this.tokenManager = tokenManager;
        this.realm = session.getContext().getRealm();
        this.event = event;
        this.request = session.getContext().getHttpRequest();
        this.httpResponse = session.getContext().getHttpResponse();
        this.headers = session.getContext().getRequestHeaders();
    }

    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @POST
    public Response processGrantRequest() {
        if (Profile.isFeatureEnabled(Profile.Feature.MAP_STORAGE)) {
            // grant request needs to be run in a retriable transaction as concurrent execution of this action can lead to
            // exceptions on DBs with SERIALIZABLE isolation level.
            return KeycloakModelUtils.runJobInRetriableTransaction(session.getKeycloakSessionFactory(), new ResponseSessionTask(session) {
                @Override
                public Response runInternal(KeycloakSession session) {
                    // create another instance of the endpoint to isolate each run.
                    TokenEndpoint other = new TokenEndpoint(session, tokenManager,
                            new EventBuilder(session.getContext().getRealm(), session, clientConnection));
                    // process the request in the created instance.
                    return other.processGrantRequestInternal();
                }
            }, 10, 100);
        } else {
            return processGrantRequestInternal();
        }
    }

    private Response processGrantRequestInternal() {
        cors = Cors.add(request).auth().allowedMethods("POST").auth().exposedHeaders(Cors.ACCESS_CONTROL_ALLOW_METHODS);

        MultivaluedMap<String, String> formParameters = request.getDecodedFormParameters();

        if (formParameters == null) {
            formParameters = new MultivaluedHashMap<>();
        }

        formParams = formParameters;
        grantType = formParams.getFirst(OIDCLoginProtocol.GRANT_TYPE_PARAM);

        // https://tools.ietf.org/html/rfc6749#section-5.1
        // The authorization server MUST include the HTTP "Cache-Control" response header field
        // with a value of "no-store" as well as the "Pragma" response header field with a value of "no-cache".
        httpResponse.setHeader("Cache-Control", "no-store");
        httpResponse.setHeader("Pragma", "no-cache");

        checkSsl();
        checkRealm();
        checkGrantType();

        if (!action.equals(Action.PERMISSION)) {
            checkClient();
            checkParameterDuplicated();
        }

        switch (action) {
            case AUTHORIZATION_CODE:
                return codeToToken();
            case REFRESH_TOKEN:
                return refreshTokenGrant();
            case PASSWORD:
                return resourceOwnerPasswordCredentialsGrant();
            case CLIENT_CREDENTIALS:
                return clientCredentialsGrant();
            case TOKEN_EXCHANGE:
                return tokenExchange();
            case PERMISSION:
                return permissionGrant();
            case OAUTH2_DEVICE_CODE:
                return oauth2DeviceCodeToToken();
            case CIBA:
                return cibaGrant();
        }

        throw new RuntimeException("Unknown action " + action);
    }

    @Path("introspect")
    public Object introspect() {
        return new TokenIntrospectionEndpoint(this.session, this.event);
    }

    @OPTIONS
    public Response preflight() {
        if (logger.isDebugEnabled()) {
            logger.debugv("CORS preflight from: {0}", headers.getRequestHeaders().getFirst("Origin"));
        }
        return Cors.add(request, Response.ok()).auth().preflight().allowedMethods("POST", "OPTIONS").build();
    }

    private void checkSsl() {
        if (!session.getContext().getUri().getBaseUri().getScheme().equals("https") && realm.getSslRequired().isRequired(clientConnection)) {
            throw new CorsErrorResponseException(cors.allowAllOrigins(), OAuthErrorException.INVALID_REQUEST, "HTTPS required", Response.Status.FORBIDDEN);
        }
    }

    private void checkRealm() {
        if (!realm.isEnabled()) {
            throw new CorsErrorResponseException(cors.allowAllOrigins(), "access_denied", "Realm not enabled", Response.Status.FORBIDDEN);
        }
    }

    private void checkClient() {
        AuthorizeClientUtil.ClientAuthResult clientAuth = AuthorizeClientUtil.authorizeClient(session, event, cors);
        client = clientAuth.getClient();
        clientAuthAttributes = clientAuth.getClientAuthAttributes();
        clientConfig = OIDCAdvancedConfigWrapper.fromClientModel(client);

        cors.allowedOrigins(session, client);

        if (client.isBearerOnly()) {
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_CLIENT, "Bearer-only not allowed", Response.Status.BAD_REQUEST);
        }


    }

    private void checkGrantType() {
        if (grantType == null) {
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_REQUEST, "Missing form parameter: " + OIDCLoginProtocol.GRANT_TYPE_PARAM, Response.Status.BAD_REQUEST);
        }

        if (grantType.equals(OAuth2Constants.AUTHORIZATION_CODE)) {
            event.event(EventType.CODE_TO_TOKEN);
            action = Action.AUTHORIZATION_CODE;
        } else if (grantType.equals(OAuth2Constants.REFRESH_TOKEN)) {
            event.event(EventType.REFRESH_TOKEN);
            action = Action.REFRESH_TOKEN;
        } else if (grantType.equals(OAuth2Constants.PASSWORD)) {
            event.event(EventType.LOGIN);
            action = Action.PASSWORD;
        } else if (grantType.equals(OAuth2Constants.CLIENT_CREDENTIALS)) {
            event.event(EventType.CLIENT_LOGIN);
            action = Action.CLIENT_CREDENTIALS;
        } else if (grantType.equals(OAuth2Constants.TOKEN_EXCHANGE_GRANT_TYPE)) {
            event.event(EventType.TOKEN_EXCHANGE);
            action = Action.TOKEN_EXCHANGE;
        } else if (grantType.equals(OAuth2Constants.UMA_GRANT_TYPE)) {
            event.event(EventType.PERMISSION_TOKEN);
            action = Action.PERMISSION;
        } else if (grantType.equals(OAuth2Constants.DEVICE_CODE_GRANT_TYPE)) {
            event.event(EventType.OAUTH2_DEVICE_CODE_TO_TOKEN);
            action = Action.OAUTH2_DEVICE_CODE;
        } else if (grantType.equals(OAuth2Constants.CIBA_GRANT_TYPE)) {
            event.event(EventType.AUTHREQID_TO_TOKEN);
            action = Action.CIBA;
        } else {
            throw new CorsErrorResponseException(cors, OAuthErrorException.UNSUPPORTED_GRANT_TYPE,
                "Unsupported " + OIDCLoginProtocol.GRANT_TYPE_PARAM, Response.Status.BAD_REQUEST);
        }

        event.detail(Details.GRANT_TYPE, grantType);
    }

    private void checkParameterDuplicated() {
        for (String key : formParams.keySet()) {
            if (formParams.get(key).size() != 1) {
                throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_REQUEST, "duplicated parameter",
                    Response.Status.BAD_REQUEST);
            }
        }
    }

    private void checkAndRetrieveDPoPProof(boolean isDPoPSupported) {
        if (!isDPoPSupported) return;

        if (clientConfig.isUseDPoP() || request.getHttpHeaders().getHeaderString(DPoPUtil.DPOP_HTTP_HEADER) != null) {
            try {
                dPoP = new DPoPUtil.Validator(session).request(request).uriInfo(session.getContext().getUri()).validate();
                session.setAttribute(DPoPUtil.DPOP_SESSION_ATTRIBUTE, dPoP);
            } catch (VerificationException ex) {
                event.error(Errors.INVALID_DPOP_PROOF);
                throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_DPOP_PROOF, ex.getMessage(), Response.Status.BAD_REQUEST);
            }
        }
    }

    public Response codeToToken() {
        checkAndRetrieveDPoPProof(Profile.isFeatureEnabled(Profile.Feature.DPOP));

        String code = formParams.getFirst(OAuth2Constants.CODE);
        if (code == null) {
            event.error(Errors.INVALID_CODE);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_REQUEST, "Missing parameter: " + OAuth2Constants.CODE, Response.Status.BAD_REQUEST);
        }

        OAuth2CodeParser.ParseResult parseResult = OAuth2CodeParser.parseCode(session, code, realm, event);
        if (parseResult.isIllegalCode()) {
            AuthenticatedClientSessionModel clientSession = parseResult.getClientSession();

            // Attempt to use same code twice should invalidate existing clientSession
            if (clientSession != null) {
                clientSession.detachFromUserSession();
            }

            event.error(Errors.INVALID_CODE);

            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "Code not valid", Response.Status.BAD_REQUEST);
        }

        AuthenticatedClientSessionModel clientSession = parseResult.getClientSession();

        if (parseResult.isExpiredCode()) {
            event.error(Errors.EXPIRED_CODE);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "Code is expired", Response.Status.BAD_REQUEST);
        }

        UserSessionModel userSession = null;
        if (clientSession != null) {
            userSession = clientSession.getUserSession();
        }

        if (userSession == null) {
            event.error(Errors.USER_SESSION_NOT_FOUND);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "User session not found", Response.Status.BAD_REQUEST);
        }


        UserModel user = userSession.getUser();
        if (user == null) {
            event.error(Errors.USER_NOT_FOUND);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "User not found", Response.Status.BAD_REQUEST);
        }

        event.user(userSession.getUser());

        if (!user.isEnabled()) {
            event.error(Errors.USER_DISABLED);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "User disabled", Response.Status.BAD_REQUEST);
        }

        OAuth2Code codeData = parseResult.getCodeData();
        String redirectUri = codeData.getRedirectUriParam();
        String redirectUriParam = formParams.getFirst(OAuth2Constants.REDIRECT_URI);

        // KEYCLOAK-4478 Backwards compatibility with the adapters earlier than KC 3.4.2
        if (redirectUriParam != null && redirectUriParam.contains("session_state=") && !redirectUri.contains("session_state=")) {
            redirectUriParam = KeycloakUriBuilder.fromUri(redirectUriParam)
                    .replaceQueryParam(OAuth2Constants.SESSION_STATE, null)
                    .build().toString();
        }

        if (redirectUri != null && !redirectUri.equals(redirectUriParam)) {
            event.error(Errors.INVALID_CODE);
            logger.tracef("Parameter 'redirect_uri' did not match originally saved redirect URI used in initial OIDC request. Saved redirectUri: %s, redirectUri parameter: %s", redirectUri, redirectUriParam);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "Incorrect redirect_uri", Response.Status.BAD_REQUEST);
        }

        if (!client.getClientId().equals(clientSession.getClient().getClientId())) {
            event.error(Errors.INVALID_CODE);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "Auth error", Response.Status.BAD_REQUEST);
        }

        if (!client.isStandardFlowEnabled()) {
            event.error(Errors.NOT_ALLOWED);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "Client not allowed to exchange code", Response.Status.BAD_REQUEST);
        }

        if (!AuthenticationManager.isSessionValid(realm, userSession)) {
            event.error(Errors.USER_SESSION_NOT_FOUND);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "Session not active", Response.Status.BAD_REQUEST);
        }

        // https://tools.ietf.org/html/rfc7636#section-4.6
        String codeVerifier = formParams.getFirst(OAuth2Constants.CODE_VERIFIER);
        String codeChallenge = codeData.getCodeChallenge();
        String codeChallengeMethod = codeData.getCodeChallengeMethod();
        String authUserId = user.getId();
        String authUsername = user.getUsername();
        if (authUserId == null) {
            authUserId = "unknown";
        }
        if (authUsername == null) {
            authUsername = "unknown";
        }

        if (codeChallengeMethod != null && !codeChallengeMethod.isEmpty()) {
            PkceUtils.checkParamsForPkceEnforcedClient(codeVerifier, codeChallenge, codeChallengeMethod, authUserId, authUsername, event, cors);
        } else {
            // PKCE Activation is OFF, execute the codes implemented in KEYCLOAK-2604
            PkceUtils.checkParamsForPkceNotEnforcedClient(codeVerifier, codeChallenge, codeChallengeMethod, authUserId, authUsername, event, cors);
        }

        try {
            session.clientPolicy().triggerOnEvent(new TokenRequestContext(formParams, parseResult));
        } catch (ClientPolicyException cpe) {
            event.error(cpe.getError());
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, cpe.getErrorDetail(), Response.Status.BAD_REQUEST);
        }

        updateClientSession(clientSession);
        updateUserSessionFromClientAuth(userSession);

        // Compute client scopes again from scope parameter. Check if user still has them granted
        // (but in code-to-token request, it could just theoretically happen that they are not available)
        String scopeParam = codeData.getScope();
        Supplier<Stream<ClientScopeModel>> clientScopesSupplier = () -> TokenManager.getRequestedClientScopes(scopeParam, client);
        if (!TokenManager.verifyConsentStillAvailable(session, user, client, clientScopesSupplier.get())) {
            event.error(Errors.NOT_ALLOWED);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_SCOPE, "Client no longer has requested consent from user", Response.Status.BAD_REQUEST);
        }

        ClientSessionContext clientSessionCtx = DefaultClientSessionContext.fromClientSessionAndScopeParameter(clientSession, scopeParam, session);

        // Set nonce as an attribute in the ClientSessionContext. Will be used for the token generation
        clientSessionCtx.setAttribute(OIDCLoginProtocol.NONCE_PARAM, codeData.getNonce());

        return createTokenResponse(user, userSession, clientSessionCtx, scopeParam, true, s -> {return new TokenResponseContext(formParams, parseResult, clientSessionCtx, s);});
    }

    public Response createTokenResponse(UserModel user, UserSessionModel userSession, ClientSessionContext clientSessionCtx,
        String scopeParam, boolean code, Function<TokenManager.AccessTokenResponseBuilder, ClientPolicyContext> clientPolicyContextGenerator) {
        AccessToken token = tokenManager.createClientAccessToken(session, realm, client, user, userSession, clientSessionCtx);

        TokenManager.AccessTokenResponseBuilder responseBuilder = tokenManager
            .responseBuilder(realm, client, event, session, userSession, clientSessionCtx).accessToken(token);
        boolean useRefreshToken = clientConfig.isUseRefreshToken();
        if (useRefreshToken) {
            responseBuilder.generateRefreshToken();
        }

        checkAndBindMtlsHoKToken(responseBuilder, useRefreshToken);
        checkAndBindDPoPToken(responseBuilder, useRefreshToken && client.isPublicClient(), Profile.isFeatureEnabled(Profile.Feature.DPOP));

        if (TokenUtil.isOIDCRequest(scopeParam)) {
            responseBuilder.generateIDToken().generateAccessTokenHash();
        }

        if (clientPolicyContextGenerator != null) {
            try {
                session.clientPolicy().triggerOnEvent(clientPolicyContextGenerator.apply(responseBuilder));
            } catch (ClientPolicyException cpe) {
                event.error(cpe.getError());
                throw new CorsErrorResponseException(cors, cpe.getError(), cpe.getErrorDetail(), cpe.getErrorStatus());
            }
        }

        AccessTokenResponse res = null;
        if (code) {
            try {
                res = responseBuilder.build();
            } catch (RuntimeException re) {
                if ("can not get encryption KEK".equals(re.getMessage())) {
                    throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_REQUEST,
                        "can not get encryption KEK", Response.Status.BAD_REQUEST);
                } else {
                    throw re;
                }
            }
        } else {
            res = responseBuilder.build();
        }

        event.success();

        return cors.builder(Response.ok(res).type(MediaType.APPLICATION_JSON_TYPE)).build();
    }

    private void checkAndBindMtlsHoKToken(TokenManager.AccessTokenResponseBuilder responseBuilder, boolean useRefreshToken) {
        // KEYCLOAK-6771 Certificate Bound Token
        // https://tools.ietf.org/html/draft-ietf-oauth-mtls-08#section-3
        if (clientConfig.isUseMtlsHokToken()) {
            AccessToken.Confirmation confirmation = MtlsHoKTokenUtil.bindTokenWithClientCertificate(request, session);
            if (confirmation != null) {
                responseBuilder.getAccessToken().setConfirmation(confirmation);
                if (useRefreshToken) {
                    responseBuilder.getRefreshToken().setConfirmation(confirmation);
                }
            } else {
                event.error(Errors.INVALID_REQUEST);
                throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_REQUEST,
                        "Client Certification missing for MTLS HoK Token Binding", Response.Status.BAD_REQUEST);
            }
        }
    }

    private void checkAndBindDPoPToken(TokenManager.AccessTokenResponseBuilder responseBuilder, boolean useRefreshToken, boolean isDPoPSupported) {
        if (!isDPoPSupported) return;

        if (clientConfig.isUseDPoP() || dPoP != null) {
            DPoPUtil.bindToken(responseBuilder.getAccessToken(), dPoP);
            responseBuilder.getAccessToken().type(DPoPUtil.DPOP_TOKEN_TYPE);
            responseBuilder.responseTokenType(DPoPUtil.DPOP_TOKEN_TYPE);

            // Bind refresh tokens for public clients, See "Section 5. DPoP Access Token Request" from DPoP specification
            if (useRefreshToken) {
                DPoPUtil.bindToken(responseBuilder.getRefreshToken(), dPoP);
            }
        }
    }

    public Response refreshTokenGrant() {
        checkAndRetrieveDPoPProof(Profile.isFeatureEnabled(Profile.Feature.DPOP));

        String refreshToken = formParams.getFirst(OAuth2Constants.REFRESH_TOKEN);
        if (refreshToken == null) {
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_REQUEST, "No refresh token", Response.Status.BAD_REQUEST);
        }

        try {
            session.clientPolicy().triggerOnEvent(new TokenRefreshContext(formParams));
            refreshToken = formParams.getFirst(OAuth2Constants.REFRESH_TOKEN);
        } catch (ClientPolicyException cpe) {
            event.error(cpe.getError());
            throw new CorsErrorResponseException(cors, cpe.getError(), cpe.getErrorDetail(), cpe.getErrorStatus());
        }

        AccessTokenResponse res;
        try {
            // KEYCLOAK-6771 Certificate Bound Token
            TokenManager.AccessTokenResponseBuilder responseBuilder = tokenManager.refreshAccessToken(session, session.getContext().getUri(), clientConnection, realm, client, refreshToken, event, headers, request);

            session.clientPolicy().triggerOnEvent(new TokenRefreshResponseContext(formParams, responseBuilder));

            checkAndBindMtlsHoKToken(responseBuilder, clientConfig.isUseRefreshToken());
            checkAndBindDPoPToken(responseBuilder, clientConfig.isUseRefreshToken() && (client.isPublicClient() || client.isBearerOnly()), Profile.isFeatureEnabled(Profile.Feature.DPOP));

            res = responseBuilder.build();

            if (!responseBuilder.isOfflineToken()) {
                UserSessionModel userSession = lockUserSessionsForModification(session, () -> session.sessions().getUserSession(realm, res.getSessionState()));
                AuthenticatedClientSessionModel clientSession = userSession.getAuthenticatedClientSessionByClient(client.getId());
                updateClientSession(clientSession);
                updateUserSessionFromClientAuth(userSession);
            }
        } catch (OAuthErrorException e) {
            logger.trace(e.getMessage(), e);
            // KEYCLOAK-6771 Certificate Bound Token
            if (MtlsHoKTokenUtil.CERT_VERIFY_ERROR_DESC.equals(e.getDescription())) {
                event.error(Errors.NOT_ALLOWED);
                throw new CorsErrorResponseException(cors, e.getError(), e.getDescription(), Response.Status.UNAUTHORIZED);
            } else {
                event.error(Errors.INVALID_TOKEN);
                throw new CorsErrorResponseException(cors, e.getError(), e.getDescription(), Response.Status.BAD_REQUEST);
            }
        } catch (ClientPolicyException cpe) {
            event.error(cpe.getError());
            throw new CorsErrorResponseException(cors, cpe.getError(), cpe.getErrorDetail(), cpe.getErrorStatus());
        }

        event.success();

        return cors.builder(Response.ok(res, MediaType.APPLICATION_JSON_TYPE)).build();
    }

    private void updateClientSession(AuthenticatedClientSessionModel clientSession) {

        if(clientSession == null) {
            ServicesLogger.LOGGER.clientSessionNull();
            return;
        }

        String adapterSessionId = formParams.getFirst(AdapterConstants.CLIENT_SESSION_STATE);
        if (adapterSessionId != null) {
            String adapterSessionHost = formParams.getFirst(AdapterConstants.CLIENT_SESSION_HOST);
            logger.debugf("Adapter Session '%s' saved in ClientSession for client '%s'. Host is '%s'", adapterSessionId, client.getClientId(), adapterSessionHost);

            String oldClientSessionState = clientSession.getNote(AdapterConstants.CLIENT_SESSION_STATE);
            if (!adapterSessionId.equals(oldClientSessionState)) {
                clientSession.setNote(AdapterConstants.CLIENT_SESSION_STATE, adapterSessionId);
            }

            String oldClientSessionHost = clientSession.getNote(AdapterConstants.CLIENT_SESSION_HOST);
            if (!Objects.equals(adapterSessionHost, oldClientSessionHost)) {
                clientSession.setNote(AdapterConstants.CLIENT_SESSION_HOST, adapterSessionHost);
            }
        }
    }

    private void updateUserSessionFromClientAuth(UserSessionModel userSession) {
        for (Map.Entry<String, String> attr : clientAuthAttributes.entrySet()) {
            userSession.setNote(attr.getKey(), attr.getValue());
        }
    }

    public Response resourceOwnerPasswordCredentialsGrant() {
        event.detail(Details.AUTH_METHOD, "oauth_credentials");

        if (!client.isDirectAccessGrantsEnabled()) {
            event.error(Errors.NOT_ALLOWED);
            throw new CorsErrorResponseException(cors, OAuthErrorException.UNAUTHORIZED_CLIENT, "Client not allowed for direct access grants", Response.Status.BAD_REQUEST);
        }

        if (client.isConsentRequired()) {
            event.error(Errors.CONSENT_DENIED);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_CLIENT, "Client requires user consent", Response.Status.BAD_REQUEST);
        }

        try {
            session.clientPolicy().triggerOnEvent(new ResourceOwnerPasswordCredentialsContext(formParams));
        } catch (ClientPolicyException cpe) {
            event.error(cpe.getError());
            throw new CorsErrorResponseException(cors, cpe.getError(), cpe.getErrorDetail(), cpe.getErrorStatus());
        }

        String scope = getRequestedScopes();

        RootAuthenticationSessionModel rootAuthSession = new AuthenticationSessionManager(session).createAuthenticationSession(realm, false);
        AuthenticationSessionModel authSession = rootAuthSession.createAuthenticationSession(client);

        authSession.setProtocol(OIDCLoginProtocol.LOGIN_PROTOCOL);
        authSession.setAction(AuthenticatedClientSessionModel.Action.AUTHENTICATE.name());
        authSession.setClientNote(OIDCLoginProtocol.ISSUER, Urls.realmIssuer(session.getContext().getUri().getBaseUri(), realm.getName()));
        authSession.setClientNote(OIDCLoginProtocol.SCOPE_PARAM, scope);

        AuthenticationFlowModel flow = AuthenticationFlowResolver.resolveDirectGrantFlow(authSession);
        String flowId = flow.getId();
        AuthenticationProcessor processor = new AuthenticationProcessor();
        processor.setAuthenticationSession(authSession)
                .setFlowId(flowId)
                .setConnection(clientConnection)
                .setEventBuilder(event)
                .setRealm(realm)
                .setSession(session)
                .setUriInfo(session.getContext().getUri())
                .setRequest(request);
        Response challenge = processor.authenticateOnly();
        if (challenge != null) {
            // Remove authentication session as "Resource Owner Password Credentials Grant" is single-request scoped authentication
            new AuthenticationSessionManager(session).removeAuthenticationSession(realm, authSession, false);
            cors.build(httpResponse);
            return challenge;
        }
        processor.evaluateRequiredActionTriggers();
        UserModel user = authSession.getAuthenticatedUser();
        if (user.getRequiredActionsStream().count() > 0 || authSession.getRequiredActions().size() > 0) {
            // Remove authentication session as "Resource Owner Password Credentials Grant" is single-request scoped authentication
            new AuthenticationSessionManager(session).removeAuthenticationSession(realm, authSession, false);
            event.error(Errors.RESOLVE_REQUIRED_ACTIONS);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "Account is not fully set up", Response.Status.BAD_REQUEST);

        }

        AuthenticationManager.setClientScopesInSession(authSession);

        ClientSessionContext clientSessionCtx = processor.attachSession();
        UserSessionModel userSession = processor.getUserSession();
        updateUserSessionFromClientAuth(userSession);

        TokenManager.AccessTokenResponseBuilder responseBuilder = tokenManager
            .responseBuilder(realm, client, event, session, userSession, clientSessionCtx).generateAccessToken();
        boolean useRefreshToken = clientConfig.isUseRefreshToken();
        if (useRefreshToken) {
            responseBuilder.generateRefreshToken();
        }

        String scopeParam = clientSessionCtx.getClientSession().getNote(OAuth2Constants.SCOPE);
        if (TokenUtil.isOIDCRequest(scopeParam)) {
            responseBuilder.generateIDToken().generateAccessTokenHash();
        }

        checkAndBindMtlsHoKToken(responseBuilder, useRefreshToken);

        try {
            session.clientPolicy().triggerOnEvent(new ResourceOwnerPasswordCredentialsResponseContext(formParams, clientSessionCtx, responseBuilder));
        } catch (ClientPolicyException cpe) {
            event.error(cpe.getError());
            throw new CorsErrorResponseException(cors, cpe.getError(), cpe.getErrorDetail(), cpe.getErrorStatus());
        }

        AccessTokenResponse res = responseBuilder.build();

        event.success();
        AuthenticationManager.logSuccess(session, authSession);

        return cors.builder(Response.ok(res, MediaType.APPLICATION_JSON_TYPE)).build();
    }

    public Response clientCredentialsGrant() {
        if (client.isBearerOnly()) {
            event.error(Errors.INVALID_CLIENT);
            throw new CorsErrorResponseException(cors, OAuthErrorException.UNAUTHORIZED_CLIENT, "Bearer-only client not allowed to retrieve service account", Response.Status.UNAUTHORIZED);
        }
        if (client.isPublicClient()) {
            event.error(Errors.INVALID_CLIENT);
            throw new CorsErrorResponseException(cors, OAuthErrorException.UNAUTHORIZED_CLIENT, "Public client not allowed to retrieve service account", Response.Status.UNAUTHORIZED);
        }
        if (!client.isServiceAccountsEnabled()) {
            event.error(Errors.INVALID_CLIENT);
            throw new CorsErrorResponseException(cors, OAuthErrorException.UNAUTHORIZED_CLIENT, "Client not enabled to retrieve service account", Response.Status.UNAUTHORIZED);
        }

        UserModel clientUser = session.users().getServiceAccount(client);

        if (clientUser == null || client.getProtocolMapperByName(OIDCLoginProtocol.LOGIN_PROTOCOL, ServiceAccountConstants.CLIENT_ID_PROTOCOL_MAPPER) == null) {
            // May need to handle bootstrap here as well
            logger.debugf("Service account user for client '%s' not found or default protocol mapper for service account not found. Creating now", client.getClientId());
            new ClientManager(new RealmManager(session)).enableServiceAccount(client);
            clientUser = session.users().getServiceAccount(client);
        }

        String clientUsername = clientUser.getUsername();
        event.detail(Details.USERNAME, clientUsername);
        event.user(clientUser);

        if (!clientUser.isEnabled()) {
            event.error(Errors.USER_DISABLED);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_REQUEST, "User '" + clientUsername + "' disabled", Response.Status.UNAUTHORIZED);
        }

        String scope = getRequestedScopes();

        RootAuthenticationSessionModel rootAuthSession = new AuthenticationSessionManager(session).createAuthenticationSession(realm, false);
        AuthenticationSessionModel authSession = rootAuthSession.createAuthenticationSession(client);

        authSession.setAuthenticatedUser(clientUser);
        authSession.setProtocol(OIDCLoginProtocol.LOGIN_PROTOCOL);
        authSession.setClientNote(OIDCLoginProtocol.ISSUER, Urls.realmIssuer(session.getContext().getUri().getBaseUri(), realm.getName()));
        authSession.setClientNote(OIDCLoginProtocol.SCOPE_PARAM, scope);

        // persisting of userSession by default
        UserSessionModel.SessionPersistenceState sessionPersistenceState = UserSessionModel.SessionPersistenceState.PERSISTENT;

        boolean useRefreshToken = clientConfig.isUseRefreshTokenForClientCredentialsGrant();
        if (!useRefreshToken) {
            // we don't want to store a session hence we mark it as transient, see KEYCLOAK-9551
            sessionPersistenceState = UserSessionModel.SessionPersistenceState.TRANSIENT;
        }

        UserSessionModel userSession = new UserSessionManager(session).createUserSession(authSession.getParentSession().getId(), realm, clientUser, clientUsername,
                clientConnection.getRemoteAddr(), ServiceAccountConstants.CLIENT_AUTH, false, null, null, sessionPersistenceState);
        event.session(userSession);

        AuthenticationManager.setClientScopesInSession(authSession);
        ClientSessionContext clientSessionCtx = TokenManager.attachAuthenticationSession(session, userSession, authSession);

        // Notes about client details
        userSession.setNote(ServiceAccountConstants.CLIENT_ID_SESSION_NOTE, client.getClientId()); // This is for backwards compatibility
        userSession.setNote(ServiceAccountConstants.CLIENT_ID, client.getClientId());
        userSession.setNote(ServiceAccountConstants.CLIENT_HOST, clientConnection.getRemoteHost());
        userSession.setNote(ServiceAccountConstants.CLIENT_ADDRESS, clientConnection.getRemoteAddr());

        try {
            session.clientPolicy().triggerOnEvent(new ServiceAccountTokenRequestContext(formParams, clientSessionCtx.getClientSession()));
        } catch (ClientPolicyException cpe) {
            event.error(cpe.getError());
            throw new CorsErrorResponseException(cors, cpe.getError(), cpe.getErrorDetail(), Response.Status.BAD_REQUEST);
        }

        updateUserSessionFromClientAuth(userSession);

        TokenManager.AccessTokenResponseBuilder responseBuilder = tokenManager.responseBuilder(realm, client, event, session, userSession, clientSessionCtx)
                .generateAccessToken();

        // Make refresh token generation optional, see KEYCLOAK-9551
        if (useRefreshToken) {
            responseBuilder = responseBuilder.generateRefreshToken();
        } else {
            responseBuilder.getAccessToken().setSessionState(null);
        }

        checkAndBindMtlsHoKToken(responseBuilder, useRefreshToken);

        String scopeParam = clientSessionCtx.getClientSession().getNote(OAuth2Constants.SCOPE);
        if (TokenUtil.isOIDCRequest(scopeParam)) {
            responseBuilder.generateIDToken().generateAccessTokenHash();
        }

        try {
            session.clientPolicy().triggerOnEvent(new ServiceAccountTokenResponseContext(formParams, clientSessionCtx.getClientSession(), responseBuilder));
        } catch (ClientPolicyException cpe) {
            event.error(cpe.getError());
            throw new CorsErrorResponseException(cors, cpe.getError(), cpe.getErrorDetail(), Response.Status.BAD_REQUEST);
        }

        // TODO : do the same as codeToToken()
        AccessTokenResponse res = null;
        try {
            res = responseBuilder.build();
        } catch (RuntimeException re) {
            if ("can not get encryption KEK".equals(re.getMessage())) {
                throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_REQUEST,
                        "can not get encryption KEK", Response.Status.BAD_REQUEST);
            } else {
                throw re;
            }
        }
        event.success();

        return cors.builder(Response.ok(res, MediaType.APPLICATION_JSON_TYPE)).build();
    }

    private String getRequestedScopes() {
        String scope = formParams.getFirst(OAuth2Constants.SCOPE);

        boolean validScopes;
        if (Profile.isFeatureEnabled(Profile.Feature.DYNAMIC_SCOPES)) {
            AuthorizationRequestContext authorizationRequestContext = AuthorizationContextUtil.getAuthorizationRequestContextFromScopes(session, scope);
            validScopes = TokenManager.isValidScope(scope, authorizationRequestContext, client);
        } else {
            validScopes = TokenManager.isValidScope(scope, client);
        }

        if (!validScopes) {
            event.error(Errors.INVALID_REQUEST);
            throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_SCOPE, "Invalid scopes: " + scope,
                    Status.BAD_REQUEST);
        }

        return scope;
    }

    public Response tokenExchange() {
        ProfileHelper.requireFeature(Profile.Feature.TOKEN_EXCHANGE);

        event.detail(Details.AUTH_METHOD, "token_exchange");
        event.client(client);

        TokenExchangeContext context = new TokenExchangeContext(
                session,
                formParams,
                cors,
                realm,
                event,
                client,
                clientConnection,
                headers,
                tokenManager,
                clientAuthAttributes);

        return session.getKeycloakSessionFactory()
                .getProviderFactoriesStream(TokenExchangeProvider.class)
                .sorted((f1, f2) -> f2.order() - f1.order())
                .map(f -> session.getProvider(TokenExchangeProvider.class, f.getId()))
                .filter(p -> p.supports(context))
                .findFirst()
                .orElseThrow(() -> new InternalServerErrorException("No token exchange provider available"))
                .exchange(context);
    }

    public Response permissionGrant() {
        event.detail(Details.AUTH_METHOD, "oauth_credentials");

        String accessTokenString = null;
        String authorizationHeader = headers.getRequestHeaders().getFirst(HttpHeaders.AUTHORIZATION);

        if (authorizationHeader != null && authorizationHeader.toLowerCase().startsWith("bearer")) {
            accessTokenString = new AppAuthManager().extractAuthorizationHeaderToken(headers);
        }

        // we allow public clients to authenticate using a bearer token, where the token should be a valid access token.
        // public clients don't have secret and should be able to obtain a RPT by providing an access token previously issued by the server
        if (accessTokenString != null) {
            AccessToken accessToken = Tokens.getAccessToken(session);

            if (accessToken == null) {
                try {
                    // In case the access token is invalid because it's expired or the user is disabled, identify the client
                    // from the access token anyway in order to set correct CORS headers.
                    AccessToken invalidToken = new JWSInput(accessTokenString).readJsonContent(AccessToken.class);
                    ClientModel client = realm.getClientByClientId(invalidToken.getIssuedFor());
                    cors.allowedOrigins(session, client);
                    event.client(client);
                } catch (JWSInputException ignore) {
                }
                event.error(Errors.INVALID_TOKEN);
                throw new CorsErrorResponseException(cors, OAuthErrorException.INVALID_GRANT, "Invalid bearer token", Status.UNAUTHORIZED);
            }

            ClientModel client = realm.getClientByClientId(accessToken.getIssuedFor());

            session.getContext().setClient(client);

            cors.allowedOrigins(session, client);
            event.client(client);
        }

        String claimToken = null;

        // claim_token is optional, if provided we just grab it from the request
        if (formParams.containsKey("claim_token")) {
            claimToken = formParams.get("claim_token").get(0);
        }

        String claimTokenFormat = formParams.getFirst("claim_token_format");

        if (claimToken != null && claimTokenFormat == null) {
            claimTokenFormat = AuthorizationTokenService.CLAIM_TOKEN_FORMAT_ID_TOKEN;
        }

        String subjectToken = formParams.getFirst("subject_token");

        if (accessTokenString == null) {
            // in case no bearer token is provided, we force client authentication
            checkClient();

            // if a claim token is provided, we check if the format is a OpenID Connect IDToken and assume the token represents the identity asking for permissions
            if (AuthorizationTokenService.CLAIM_TOKEN_FORMAT_ID_TOKEN.equalsIgnoreCase(claimTokenFormat)) {
                accessTokenString = claimToken;
            } else if (subjectToken != null) {
                accessTokenString = subjectToken;
            } else {
                // Clients need to authenticate in order to obtain a RPT from the server.
                // In order to support cases where the client is obtaining permissions on its on behalf, we issue a temporary access token
                accessTokenString = AccessTokenResponse.class.cast(clientCredentialsGrant().getEntity()).getToken();
            }
        }

        AuthorizationTokenService.KeycloakAuthorizationRequest authorizationRequest = new AuthorizationTokenService.KeycloakAuthorizationRequest(session.getProvider(AuthorizationProvider.class),
                tokenManager, event, this.request, cors, clientConnection);

        authorizationRequest.setTicket(formParams.getFirst("ticket"));
        authorizationRequest.setClaimToken(claimToken);
        authorizationRequest.setClaimTokenFormat(claimTokenFormat);
        authorizationRequest.setPct(formParams.getFirst("pct"));

        String rpt = formParams.getFirst("rpt");

        if (rpt != null) {
            AccessToken accessToken = session.tokens().decode(rpt, AccessToken.class);
            if (accessToken == null) {
                event.error(Errors.INVALID_REQUEST);
                throw new CorsErrorResponseException(cors, "invalid_rpt", "RPT signature is invalid", Status.FORBIDDEN);
            }

            authorizationRequest.setRpt(accessToken);
        }

        authorizationRequest.setScope(formParams.getFirst("scope"));
        String audienceParam = formParams.getFirst("audience");
        authorizationRequest.setAudience(audienceParam);
        authorizationRequest.setSubjectToken(accessTokenString);

        event.detail(Details.AUDIENCE, audienceParam);

        String submitRequest = formParams.getFirst("submit_request");

        authorizationRequest.setSubmitRequest(submitRequest == null ? true : Boolean.valueOf(submitRequest));

        // permissions have a format like RESOURCE#SCOPE1,SCOPE2
        List<String> permissions = formParams.get("permission");

        if (permissions != null) {
            event.detail(Details.PERMISSION, String.join("|", permissions));
            String permissionResourceFormat = formParams.getFirst("permission_resource_format");
            boolean permissionResourceMatchingUri = Boolean.parseBoolean(formParams.getFirst("permission_resource_matching_uri"));
            authorizationRequest.addPermissions(permissions, permissionResourceFormat, permissionResourceMatchingUri);
        }

        Metadata metadata = new Metadata();

        String responseIncludeResourceName = formParams.getFirst("response_include_resource_name");

        if (responseIncludeResourceName != null) {
            metadata.setIncludeResourceName(Boolean.parseBoolean(responseIncludeResourceName));
        }

        String responsePermissionsLimit = formParams.getFirst("response_permissions_limit");

        if (responsePermissionsLimit != null) {
            metadata.setLimit(Integer.parseInt(responsePermissionsLimit));
        }

        metadata.setResponseMode(formParams.getFirst("response_mode"));

        authorizationRequest.setMetadata(metadata);

        Response authorizationResponse = AuthorizationTokenService.instance().authorize(authorizationRequest);

        event.success();

        return authorizationResponse;
    }

    public Response oauth2DeviceCodeToToken() {
        DeviceGrantType deviceGrantType = new DeviceGrantType(formParams, client, session, this, realm, event, cors);
        return deviceGrantType.oauth2DeviceFlow();
    }

    public Response cibaGrant() {
        CibaGrantType grantType = new CibaGrantType(formParams, client, session, this, realm, event, cors);
        return grantType.cibaGrant();
    }

    public static class TokenExchangeSamlProtocol extends SamlProtocol {

        final SamlClient samlClient;

        public TokenExchangeSamlProtocol(SamlClient samlClient) {
            this.samlClient = samlClient;
        }

        @Override
        protected Response buildAuthenticatedResponse(AuthenticatedClientSessionModel clientSession, String redirectUri,
                                                      Document samlDocument, JaxrsSAML2BindingBuilder bindingBuilder)
                throws ConfigurationException, ProcessingException, IOException {
            JaxrsSAML2BindingBuilder.PostBindingBuilder builder = bindingBuilder.postBinding(samlDocument);

            Element assertionElement;
            if (samlClient.requiresEncryption()) {
                assertionElement = DocumentUtil.getElement(builder.getDocument(), new QName(JBossSAMLURIConstants.ASSERTION_NSURI.get(), JBossSAMLConstants.ENCRYPTED_ASSERTION.get()));
            } else {
                assertionElement = DocumentUtil.getElement(builder.getDocument(), new QName(JBossSAMLURIConstants.ASSERTION_NSURI.get(), JBossSAMLConstants.ASSERTION.get()));
            }
            if (assertionElement == null) {
                return Response.status(Status.BAD_REQUEST).build();
            }
            String assertion = DocumentUtil.getNodeAsString(assertionElement);
            return Response.ok(assertion, MediaType.APPLICATION_XML_TYPE).build();
        }

        @Override
        protected Response buildErrorResponse(boolean isPostBinding, String destination, JaxrsSAML2BindingBuilder binding, Document document) throws ConfigurationException, ProcessingException, IOException {
            return Response.status(Status.BAD_REQUEST).build();
        }
    }
}
