KAFKA-17078: Add SecurityManagerCompatibility shim

clients/src/main/java/org/apache/kafka/common/internals/CompositeStrategy.java

@@ -0,0 +1,106 @@
+/*
+ * 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.kafka.common.internals;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.security.PrivilegedAction;
+import java.util.Objects;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Function;
+
+import javax.security.auth.Subject;
+
+/**
+ * This strategy combines the functionality of the {@link LegacyStrategy}, {@link ModernStrategy}, and
+ * {@link UnsupportedStrategy} strategies to provide the legacy APIs as long as they are present and not degraded.
+ * If the legacy APIs are missing or degraded, this falls back to the modern APIs.
+ */
+class CompositeStrategy implements SecurityManagerCompatibility {
+
+    private static final Logger log = LoggerFactory.getLogger(CompositeStrategy.class);
+    static final CompositeStrategy INSTANCE = new CompositeStrategy(ReflectiveStrategy.Loader.forName());
+
+    private final SecurityManagerCompatibility fallbackStrategy;
+    private final AtomicReference<SecurityManagerCompatibility> activeStrategy;
+
+    // Visible for testing
+    CompositeStrategy(ReflectiveStrategy.Loader loader) {
+        SecurityManagerCompatibility initial;
+        SecurityManagerCompatibility fallback = null;
+        try {
+            initial = new LegacyStrategy(loader);
+            try {
+                fallback = new ModernStrategy(loader);
+                // This is expected for JRE 18+
+                log.debug("Loaded legacy SecurityManager methods, will fall back to modern methods after UnsupportedOperationException");
+            } catch (NoSuchMethodException | ClassNotFoundException ex) {
+                // This is expected for JRE <= 17
+                log.debug("Unable to load modern Subject methods, relying only on legacy methods", ex);
+            }
+        } catch (ClassNotFoundException | NoSuchMethodException e) {
+            try {
+                initial = new ModernStrategy(loader);
+                // This is expected for JREs after the removal takes place.
+                log.debug("Unable to load legacy SecurityManager methods, relying only on modern methods", e);
+            } catch (NoSuchMethodException | ClassNotFoundException ex) {
+                initial = new UnsupportedStrategy(e, ex);
+                // This is not expected in normal use, only in test environments.
+                log.error("Unable to load legacy SecurityManager methods", e);
+                log.error("Unable to load modern Subject methods", ex);
+            }
+        }
+        Objects.requireNonNull(initial, "initial strategy must be defined");
+        activeStrategy = new AtomicReference<>(initial);
+        fallbackStrategy = fallback;
+    }
+
+    private <T> T performAction(Function<SecurityManagerCompatibility, T> action) {
+        SecurityManagerCompatibility active = activeStrategy.get();
+        try {
+            return action.apply(active);
+        } catch (UnsupportedOperationException e) {
+            // If we chose a fallback strategy during loading, switch to it and retry this operation.
+            if (active != fallbackStrategy && fallbackStrategy != null) {
+                if (activeStrategy.compareAndSet(active, fallbackStrategy)) {
+                    log.debug("Using fallback strategy after encountering degraded legacy method", e);
+                }
+                return action.apply(fallbackStrategy);
+            }
+            // If we're already using the fallback strategy, then there's nothing to do to handle these exceptions.
+            throw e;
+        }
+    }
+
+    @Override
+    public <T> T doPrivileged(PrivilegedAction<T> action) {
+        return performAction(compatibility -> compatibility.doPrivileged(action));
+    }
+
+    @Override
+    public Subject current() {
+        return performAction(SecurityManagerCompatibility::current);
+    }
+
+    @Override
+    public <T> T callAs(Subject subject, Callable<T> action) throws CompletionException {
+        return performAction(compatibility -> compatibility.callAs(subject, action));
+    }
+}

clients/src/main/java/org/apache/kafka/common/internals/LegacyStrategy.java

@@ -0,0 +1,96 @@
+/*
+ * 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.kafka.common.internals;
+
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CompletionException;
+
+import javax.security.auth.Subject;
+
+/**
+ * This class implements reflective access to the deprecated-for-removal methods of AccessController and Subject.
+ * <p>Instantiating this class may fail if any of the required classes or methods are not found.
+ * Method invocations for this class may fail with {@link UnsupportedOperationException} if all methods are found,
+ * but the operation is not permitted to be invoked.
+ * <p>This class is expected to be instantiable in JRE >=8 until the removal finally takes place.
+ */
+@SuppressWarnings("unchecked")
+class LegacyStrategy extends ReflectiveStrategy {
+
+    private final Method doPrivileged;
+    private final Method getContext;
+    private final Method getSubject;
+    private final Method doAs;
+
+    // Visible for testing
+    LegacyStrategy(Loader loader) throws ClassNotFoundException, NoSuchMethodException {
+        Class<?> accessController = loader.loadClass("java.security.AccessController");
+        doPrivileged = accessController.getDeclaredMethod("doPrivileged", PrivilegedAction.class);
+        getContext = accessController.getDeclaredMethod("getContext");
+        Class<?> accessControlContext = loader.loadClass("java.security.AccessControlContext");
+        Class<?> subject = loader.loadClass(Subject.class.getName());
+        getSubject = subject.getDeclaredMethod("getSubject", accessControlContext);
+        // Note that the Subject class isn't deprecated or removed, so reference it as an argument type.
+        // This allows for mocking out the method implementation while still accepting Subject instances as arguments.
+        doAs = subject.getDeclaredMethod("doAs", Subject.class, PrivilegedExceptionAction.class);
+    }
+
+    @Override
+    public <T> T doPrivileged(PrivilegedAction<T> action) {
+        return (T) invoke(doPrivileged, null, action);
+    }
+
+    /**
+     * @return the result of AccessController.getContext(), of type AccessControlContext
+     */
+    private Object getContext() {
+        return invoke(getContext, null);
+    }
+
+    /**
+     * @param context The current AccessControlContext
+     * @return The result of Subject.getSubject(AccessControlContext)
+     */
+    private Subject getSubject(Object context) {
+        return (Subject) invoke(getSubject, null, context);
+    }
+
+    @Override
+    public Subject current() {
+        return getSubject(getContext());
+    }
+
+    /**
+     * @return The result of Subject.doAs(Subject, PrivilegedExceptionAction)
+     */
+    private <T> T doAs(Subject subject, PrivilegedExceptionAction<T> action) throws PrivilegedActionException {
+        return (T) invokeChecked(doAs, PrivilegedActionException.class, null, subject, action);
+    }
+
+    @Override
+    public <T> T callAs(Subject subject, Callable<T> callable) throws CompletionException {
+        try {
+            return doAs(subject, callable::call);
+        } catch (PrivilegedActionException e) {
+            throw new CompletionException(e.getCause());
+        }
+    }
+}

clients/src/main/java/org/apache/kafka/common/internals/ModernStrategy.java

@@ -0,0 +1,64 @@
+/*
+ * 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.kafka.common.internals;
+
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CompletionException;
+
+import javax.security.auth.Subject;
+
+/**
+ * This class implements reflective access to the methods of Subject added to replace deprecated methods.
+ * <p>Instantiating this class may fail if any of the required classes or methods are not found.
+ * Method invocations for this class may fail with {@link UnsupportedOperationException} if all methods are found,
+ * but the operation is not permitted to be invoked.
+ * <p>This class is expected to be instantiable in JRE >= 18. At the time of writing, these methods do not have
+ * a sunset date, and are expected to be available past the removal of the SecurityManager.
+ */
+@SuppressWarnings("unchecked")
+class ModernStrategy extends ReflectiveStrategy {
+
+    private final Method current;
+    private final Method callAs;
+
+    // Visible for testing
+    ModernStrategy(Loader loader) throws NoSuchMethodException, ClassNotFoundException {
+        Class<?> subject = loader.loadClass(Subject.class.getName());
+        current = subject.getDeclaredMethod("current");
+        // Note that the Subject class isn't deprecated or removed, so reference it as an argument type.
+        // This allows for mocking out the method implementation while still accepting Subject instances as arguments.
+        callAs = subject.getDeclaredMethod("callAs", Subject.class, Callable.class);
+    }
+
+    @Override
+    public <T> T doPrivileged(PrivilegedAction<T> action) {
+        // This is intentionally a pass-through
+        return action.run();
+    }
+
+    @Override
+    public Subject current() {
+        return (Subject) invoke(current, null);
+    }
+
+    @Override
+    public <T> T callAs(Subject subject, Callable<T> action) throws CompletionException {
+        return (T) invokeChecked(callAs, CompletionException.class, null, subject, action);
+    }
+}

clients/src/main/java/org/apache/kafka/common/internals/ReflectiveStrategy.java

@@ -0,0 +1,69 @@
+/*
+ * 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.kafka.common.internals;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ * A strategy which uses reflection to access methods without requiring them at compile-time.
+ */
+abstract class ReflectiveStrategy implements SecurityManagerCompatibility {
+
+    Object invoke(Method method, Object obj, Object... args) {
+        try {
+            return method.invoke(obj, args);
+        } catch (IllegalAccessException e) {
+            throw new UnsupportedOperationException(e);
+        } catch (InvocationTargetException e) {
+            Throwable cause = e.getCause();
+            if (cause instanceof RuntimeException) {
+                throw (RuntimeException) cause;
+            } else {
+                throw new RuntimeException(cause);
+            }
+        }
+    }
+
+    <T extends Exception> Object invokeChecked(Method method, Class<T> ex, Object obj, Object... args) throws T {
+        try {
+            return method.invoke(obj, args);
+        } catch (IllegalAccessException e) {
+            throw new UnsupportedOperationException(e);
+        } catch (InvocationTargetException e) {
+            Throwable cause = e.getCause();
+            if (ex.isInstance(cause)) {
+                throw ex.cast(cause);
+            } else if (cause instanceof RuntimeException) {
+                throw (RuntimeException) cause;
+            } else {
+                throw new RuntimeException(cause);
+            }
+        }
+    }
+
+    /**
+     * Interface to allow mocking out classloading infrastructure. This is used to test reflective operations.
+     */
+    interface Loader {
+        Class<?> loadClass(String className) throws ClassNotFoundException;
+
+        static Loader forName() {
+            return className -> Class.forName(className, true, Loader.class.getClassLoader());
+        }
+    }
+}