Run tomcat by Gretty in the security mode

Question

Anyone has an example of the catalina.policy file how to get tomcat working in the security mode when I run it by gretty-gradle-plugin? I think I need some additional permissions for the gretty-gradle-plugin, but I am not able to find out which ones. My build.gradle config...

gretty { 
  servletContainer = 'tomcat85'
  jvmArgs = [
        '-Djava.security.manager=java.lang.SecurityManager',
        "-Djava.security.policy=${project.projectDir}/tomcat.8080/conf/catalina.policy"
]}