undefect. CWE-407 — 63 sites patched across 27 ecosystems

Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com

Patches, unit tests, benchmarks, whitepaper, and outreach briefs.
Public domain — no copyright claimed. Use freely.

test/jdk/java/lang/ClassLoader/forNameLeak/ClassForNameLeak.java

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+/*
+ * Copyright (c) 2016, 2024, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8151486
+ * @summary Call Class.forName() on the system classloader from a class loaded
+ *          from a custom classloader.
+ * @library /test/lib
+ * @build jdk.test.lib.Utils
+ *        jdk.test.lib.util.ForceGC
+ *        jdk.test.lib.util.JarUtils
+ * @build ClassForName ClassForNameLeak
+ * @run main/othervm ClassForNameLeak
+ */
+
+import java.io.IOException;
+import java.lang.ref.WeakReference;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import jdk.test.lib.Utils;
+import jdk.test.lib.util.ForceGC;
+import jdk.test.lib.util.JarUtils;
+
+/*
+ * Create .jar, load ClassForName from .jar using a URLClassLoader
+ */
+public class ClassForNameLeak {
+    private static final long TIMEOUT = (long)(5000.0 * Utils.TIMEOUT_FACTOR);
+    private static final int THREADS = 10;
+    private static final Path jarFilePath = Paths.get("cfn.jar");
+
+    static class TestLoader extends URLClassLoader {
+        static URL[] toURLs() {
+            try {
+                return new URL[]{jarFilePath.toUri().toURL()};
+            } catch (MalformedURLException e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+        TestLoader() {
+            super("LeakedClassLoader", toURLs(), ClassLoader.getPlatformClassLoader());
+        }
+    }
+
+    // Use a new classloader to load the ClassForName class, then run its
+    // Runnable.
+    static WeakReference<TestLoader> loadAndRun() {
+        TestLoader classLoader = new TestLoader();
+        try {
+            Class<?> loadClass = Class.forName("ClassForName", true, classLoader);
+            ((Runnable) loadClass.newInstance()).run();
+        } catch (ReflectiveOperationException ex) {
+            throw new RuntimeException(ex);
+        }
+        return new WeakReference<>(classLoader);
+    }
+
+    public static void main(String... args) throws Exception {
+        // create the JAR file
+        setup();
+
+        // Make simultaneous calls to the test method, to stress things a bit
+        ExecutorService es = Executors.newFixedThreadPool(THREADS);
+
+        List<Callable<WeakReference<TestLoader>>> callables =
+                Stream.generate(() -> {
+                    Callable<WeakReference<TestLoader>> cprcl = ClassForNameLeak::loadAndRun;
+                    return cprcl;
+                }).limit(THREADS).collect(Collectors.toList());
+
+        for (Future<WeakReference<TestLoader>> future : es.invokeAll(callables)) {
+            WeakReference<TestLoader> ref = future.get();
+            if (!ForceGC.wait(() -> ref.refersTo(null))) {
+                throw new RuntimeException(ref.get() + " not unloaded");
+            }
+        }
+        es.shutdown();
+    }
+
+    private static final String CLASSFILENAME = "ClassForName.class";
+    private static void setup() throws IOException {
+        String testclasses = System.getProperty("test.classes", ".");
+
+        // Create a temporary .jar file containing ClassForName.class
+        Path testClassesDir = Paths.get(testclasses);
+        JarUtils.createJarFile(jarFilePath, testClassesDir, CLASSFILENAME);
+    }
+}