[JBPM-10039] Incorrect groups are returned when "org.kie.server.bypas…

…s.auth.user" is set and JAASUserGroupCallbackImpl is used (kiegroup#2211)

Co-authored-by: egonzale <egonzale@redhat.com>

jbpm-human-task/jbpm-human-task-core/src/main/java/org/jbpm/services/task/identity/JAASUserGroupCallbackImpl.java

@@ -113,7 +113,7 @@ public List<String> getGroupsForUser(String userId) {
         try {
             Subject subject = getSubjectFromContainer();
 
-            if (subject != null) {
+            if (subject != null && subjectContainsUser(subject, userId)) {
                 Set<Principal> principals = subject.getPrincipals();
 
                 if (principals != null) {
@@ -157,6 +157,10 @@ public List<String> getGroupsForUser(String userId) {
         return roles;
 	}
 
+    private boolean subjectContainsUser(Subject subject, String userId) {
+        return subject.getPrincipals().stream().map(Principal::getName).anyMatch(userId::equals);
+    }
+
 	protected Subject getSubjectFromContainer() {
          try {
              return (Subject) PolicyContext.getContext( "javax.security.auth.Subject.container" );