Verify target service when issuing proxy tickets

 src/main/java/org/keycloak/protocol/cas/endpoints/AbstractValidateEndpoint.java

@@ -70,10 +70,7 @@

        event.detail(Details.REDIRECT_URI, service);

        client = realm.getClientsStream()
                .filter(c -> CASLoginProtocol.LOGIN_PROTOCOL.equals(c.getProtocol()))
                .filter(c -> RedirectUtils.verifyRedirectUri(session, service, c) != null)
                .findFirst().orElse(null);
        client = findClient(service);
        if (client == null) {
            event.error(Errors.CLIENT_NOT_FOUND);
            throw new CASValidationException(CASErrorCode.INVALID_SERVICE, "Client not found", Response.Status.BAD_REQUEST);
@@ -91,6 +88,13 @@
        session.getContext().setClient(client);
    }

    protected ClientModel findClient(String service) {
        return realm.getClientsStream()
                .filter(c -> CASLoginProtocol.LOGIN_PROTOCOL.equals(c.getProtocol()))
                .filter(c -> RedirectUtils.verifyRedirectUri(session, service, c) != null)
                .findFirst().orElse(null);
    }

    protected void checkTicket(String ticket, String prefix, boolean requireReauth) {
        if (ticket == null) {
            event.error(Errors.INVALID_CODE);

 src/main/java/org/keycloak/protocol/cas/endpoints/ProxyEndpoint.java

@@ -5,12 +5,15 @@
import jakarta.ws.rs.core.MultivaluedMap;
import jakarta.ws.rs.core.Response;
import org.jboss.resteasy.annotations.cache.NoCache;
import org.keycloak.events.Errors;
import org.keycloak.events.EventBuilder;
import org.keycloak.events.EventType;
import org.keycloak.models.*;
import org.keycloak.protocol.cas.CASLoginProtocol;
import org.keycloak.protocol.cas.representations.CASErrorCode;
import org.keycloak.protocol.cas.representations.CASServiceResponse;
import org.keycloak.protocol.cas.utils.CASValidationException;
import org.keycloak.protocol.cas.utils.RedirectUtils;
import org.keycloak.protocol.cas.utils.ContentTypeHelper;
import org.keycloak.protocol.cas.utils.ServiceResponseHelper;

@@ -33,13 +36,29 @@
            checkSsl();
            checkRealm();
            checkTicket(pgt, CASLoginProtocol.PROXY_GRANTING_TICKET_PREFIX, false);
            String verifiedTargetService = checkTargetService(targetService);
            event.success();
            return successResponse(getPT(this.session, clientSession, targetService));
            return successResponse(getPT(this.session, clientSession, verifiedTargetService));
        } catch (CASValidationException e) {
            return errorResponse(e);
        }
    }

    private String checkTargetService(String targetService) {
        if (targetService == null) {
            event.error(Errors.INVALID_REQUEST);
            throw new CASValidationException(CASErrorCode.INVALID_REQUEST, "Missing parameter: " + CASLoginProtocol.TARGET_SERVICE_PARAM, Response.Status.BAD_REQUEST);
        }

        ClientModel targetClient = findClient(targetService);
        if (targetClient == null || !targetClient.isEnabled()) {
            event.error(Errors.CLIENT_NOT_FOUND);
            throw new CASValidationException(CASErrorCode.INVALID_SERVICE, "Target service not allowed", Response.Status.BAD_REQUEST);
        }

        return RedirectUtils.verifyRedirectUri(session, targetService, targetClient);
    }

    protected Response successResponse(String pt) {
        CASServiceResponse serviceResponse = ServiceResponseHelper.createProxySuccess(pt);
        return prepare(Response.Status.OK, serviceResponse);