hwanju commented on a change in pull request #14499: URL: https://github.com/apache/flink/pull/14499#discussion_r550362614
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/security/FlinkUserSecurityManager.java ########## @@ -0,0 +1,165 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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.apache.flink.runtime.security; + +import org.apache.flink.configuration.Configuration; +import org.apache.flink.configuration.IllegalConfigurationException; +import org.apache.flink.configuration.SecurityOptions; +import org.apache.flink.runtime.UserSystemExitException; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.security.Permission; + +/** + * Flink user security manager to control unexpected user behaviors that potentially impact cluster availability, for + * example, it can warn or prevent user code from terminating JVM by System.exit or halt by logging or throwing an exception. + * This does not necessarily prevent malicious users who try to tweak security manager on their own, but more for being dependable + * against user mistakes by gracefully handling them informing users rather than causing silent unavailability. + */ +public class FlinkUserSecurityManager extends SecurityManager { + + /** + * The mode of how to handle user code attempting to exit JVM. + */ + public enum CheckExitMode { + /** No check is enabled, that is allowing exit without any action. */ + DISABLED, + /** Warn by logging but still allowing exit to be performed. */ + WARN, + /** Throw exception when exit is attempted disallowing JVM termination. */ + THROW, + } + + static final Logger LOG = LoggerFactory.getLogger(FlinkUserSecurityManager.class); + + private final SecurityManager originalSecurityManager = System.getSecurityManager(); + private ThreadLocal<Boolean> monitorSystemExit = new InheritableThreadLocal<>(); + private CheckExitMode checkExitMode; + + public FlinkUserSecurityManager(CheckExitMode checkExitMode) { + super(); + this.checkExitMode = checkExitMode; + + LOG.info("FlinkUserSecurityManager is created with {} system exit check (previous security manager is {})", + this.checkExitMode, originalSecurityManager != null ? originalSecurityManager : "not existing"); + } + + /** + * Instantiate FlinkUserSecurityManager from configuration. Return null if no security manager + * check is needed, so that a caller can skip setting security manager avoiding runtime check cost, + * if there is no security check set up already. Use {@link #setFromConfiguration} helper, which + * handles disabled case. + * + * @param configuration to instantiate the security manager from + * + * @return FlinkUserSecurityManager instantiated baesd on configuration. Return null if disabled. + */ + public static FlinkUserSecurityManager fromConfiguration(Configuration configuration) { + final String checkExitModeConfig = configuration.getString(SecurityOptions.CHECK_SYSTEM_EXIT); + final CheckExitMode checkExitMode; + + try { + checkExitMode = CheckExitMode.valueOf(checkExitModeConfig.toUpperCase()); + } catch (Exception ex) { + throw new IllegalConfigurationException( + String.format("%s is invalid configuration for %s.", checkExitModeConfig, SecurityOptions.CHECK_SYSTEM_EXIT.key()), + ex); + } + + // If no check is enabled, return null so that caller can avoid setting security manager not to incur any runtime cost. + if (checkExitMode == CheckExitMode.DISABLED) { + return null; + } + // Add more configuration parameters that need user security manager (currently only for system exit). + return new FlinkUserSecurityManager(checkExitMode); + } + + public static void setFromConfiguration(Configuration configuration) { + final FlinkUserSecurityManager flinkUserSecurityManager = + FlinkUserSecurityManager.fromConfiguration(configuration); + if (flinkUserSecurityManager != null) { + System.setSecurityManager(flinkUserSecurityManager); + } + } + + public void checkPermission(Permission perm) { + if (originalSecurityManager != null) { + originalSecurityManager.checkPermission(perm); + } + } + + public void checkPermission(Permission perm, Object context) { + if (originalSecurityManager != null) { + originalSecurityManager.checkPermission(perm, context); + } + } + + public void checkExit(int status) { Review comment: Right. Originally forwarding behavior to existing one is via checkPermission override, which is called by `super.checkExit`, but existing manager may do work in checkExit not checkPermission. I will change it. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
