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https://issues.apache.org/jira/browse/HADOOP-19574?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18017449#comment-18017449
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ASF GitHub Bot commented on HADOOP-19574:
-----------------------------------------
stoty commented on code in PR #7892:
URL: https://github.com/apache/hadoop/pull/7892#discussion_r2313987803
##########
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/concurrent/SubjectInheritingThread.java:
##########
@@ -0,0 +1,148 @@
+/**
+ * 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.hadoop.util.concurrent;
+
+import java.security.PrivilegedAction;
+import javax.security.auth.Subject;
+
+import org.apache.hadoop.security.authentication.util.SubjectUtil;
+
+/**
+ * Helper class to restore Subject propagation behavior of threads after the
+ * JEP411/JEP486 changes.
+ * <p>
+ * Java propagates the current Subject to any new Threads in all version up to
+ * Java 21. In Java 22-23 the Subject is only propagated if the SecurityManager
+ * is enabled, while in Java 24+ it is never propagated.
+ * <p>
+ * Hadoop security heavily relies on the original behavior, as Subject is at
the
+ * core of JAAS. This class wraps thread. It overrides start() and saves the
+ * Subject of the current thread, and wraps the payload in a
+ * Subject.doAs()/callAs() call to restorere it in the newly created Thread.
+ * <p>
+ * When specifying a Runnable, this class is used in exactly the same way as
+ * Thread.
+ * <p>
+ * {@link #run()} cannot be directly overridden, as that would also override
the
+ * subject restoration logic. SubjectInheritingThread provides a {@link work()}
+ * method instead, which is wrapped and invoked by its own final {@link run()}
+ * method.
+ */
+public class SubjectInheritingThread extends Thread {
+
+ private Subject startSubject;
+ // {@link Thread#target} is private, so we need our own
+ private Runnable hadoopTarget;
+
+ /**
+ * Behaves similar to {@link Thread#Thread()} constructor, but the code to
run
+ * must be specified by overriding the {@link #work()} instead of the {link
+ * #run()} method.
+ */
+ public SubjectInheritingThread() {
+ super();
+ }
+
+ /**
+ * Behaves similar to {@link Thread#Thread(Runnable)} constructor.
+ */
+ public SubjectInheritingThread(Runnable target) {
+ super();
+ this.hadoopTarget = target;
+ }
+
+ /**
+ * Behaves similar to {@link Thread#Thread(ThreadGroup, Runnable)}
constructor.
+ */
+ public SubjectInheritingThread(ThreadGroup group, Runnable target) {
+ // The target passed to Thread has no effect, we only pass it
+ // because there is no super(group) constructor.
+ super(group, target);
+ this.hadoopTarget = target;
+ }
+
+ /**
+ * Behaves similar to {@link Thread#Thread(Runnable, String)} constructor.
+ */
+ public SubjectInheritingThread(Runnable target, String name) {
+ super(name);
+ this.hadoopTarget = target;
+ }
+
+ /**
+ * Behaves similar to {@link Thread#Thread(String)} constructor.
+ */
+ public SubjectInheritingThread(String name) {
+ super(name);
+ }
+
+ /**
+ * Behaves similar to {@link Thread#Thread(ThreadGroup, String)} constructor.
+ */
+ public SubjectInheritingThread(ThreadGroup group, String name) {
+ super(group, name);
+ }
+
+ /**
+ * Behaves similar to {@link Thread#Thread(ThreadGroup, Runnable, String)}
+ * constructor.
+ */
+ public SubjectInheritingThread(ThreadGroup group, Runnable target, String
name) {
+ super(group, name);
+ this.hadoopTarget = target;
+ }
+
+ /**
+ * Behaves similar to pre-Java 22 {@link Thread#start()}. It saves the
current
+ * Subject before starting the new thread, which is then used as the Subject
for
+ * the Runnable or the overridden work() method.
+ */
+ @Override
+ public final void start() {
+ startSubject = SubjectUtil.current();
+ super.start();
+ }
+
+ /**
+ * This is the equivalent of {@link Thread#run()}. Override this instead of
+ * {@link #run()} Subject will be propagated like in pre-Java 22 Thread.
+ */
+ public void work() {
+ if (hadoopTarget != null) {
+ hadoopTarget.run();
+ }
+ }
+
+ /**
+ * This cannot be overridden in this class. Override the {@link #work()}
method
+ * instead which behaves like pre-Java 22 {@link Thread#run()}
+ */
+ @Override
+ public final void run() {
+ SubjectUtil.doAs(startSubject, new PrivilegedAction<Void>() {
Review Comment:
I think that's neglible compared to the cost of creating a new thread, but I
added a new commit to avoid it if possible, @szetszwo .
> Restore Subject propagation semantics for Java 22+
> --------------------------------------------------
>
> Key: HADOOP-19574
> URL: https://issues.apache.org/jira/browse/HADOOP-19574
> Project: Hadoop Common
> Issue Type: Improvement
> Reporter: Istvan Toth
> Assignee: Istvan Toth
> Priority: Critical
> Labels: pull-request-available
>
> Java 22 breaks Subject propagation for new Threads (when SecurityManager is
> not enabled).
> Previously, the Subject set by Subject.doAs() / Subject.callAs()
> automatically propagated to any new Threads created (via new Thread(), not
> Executors).
> With JDK22, this is no longer the case, new Threads do NOT inherit the
> Subject.
> As Hadoop heavily relies on the original behavior, we somehow need to solve
> this problem.
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