| /* |
| * Copyright (c) 1997, 2016, 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * 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. |
| */ |
| |
| package java.lang.reflect; |
| |
| import java.security.AccessController; |
| |
| import jdk.internal.reflect.CallerSensitive; |
| import jdk.internal.reflect.Reflection; |
| import jdk.internal.reflect.ReflectionFactory; |
| import java.lang.annotation.Annotation; |
| |
| /** |
| * The AccessibleObject class is the base class for Field, Method and |
| * Constructor objects. It provides the ability to flag a reflected |
| * object as suppressing default Java language access control checks |
| * when it is used. The access checks -- <em>module boundaries</em>, |
| * public, default (package) access, protected, and private members -- |
| * are performed when Fields, Methods or Constructors are used to set |
| * or get fields, to invoke methods or to create and initialize new |
| * instances of classes, respectively. Unlike access control specified |
| * in the <cite>The Java™ Language Specification</cite> and |
| * <cite>The Java Virtual Machine Specification</cite>, access checks |
| * with reflected objects assume {@link Module#canRead readability}. |
| * |
| * <p>Setting the {@code accessible} flag in a reflected object |
| * permits sophisticated applications with sufficient privilege, such |
| * as Java Object Serialization or other persistence mechanisms, to |
| * manipulate objects in a manner that would normally be prohibited. |
| * |
| * <p>By default, a reflected object is <em>not</em> accessible. |
| * |
| * @see Field |
| * @see Method |
| * @see Constructor |
| * @see ReflectPermission |
| * |
| * @since 1.2 |
| */ |
| public class AccessibleObject implements AnnotatedElement { |
| |
| /** |
| * The Permission object that is used to check whether a client |
| * has sufficient privilege to defeat Java language access |
| * control checks. |
| */ |
| private static final java.security.Permission ACCESS_PERMISSION = |
| new ReflectPermission("suppressAccessChecks"); |
| |
| static void checkPermission() { |
| SecurityManager sm = System.getSecurityManager(); |
| if (sm != null) sm.checkPermission(ACCESS_PERMISSION); |
| } |
| |
| /** |
| * Convenience method to set the {@code accessible} flag for an |
| * array of objects with a single security check (for efficiency). |
| * |
| * <p>This method cannot be used to enable access to an object that is a |
| * {@link Member member} of a class in a different module to the caller and |
| * where the class is in a package that is not exported to the caller's |
| * module. Additionally, this method cannot be used to enable access to |
| * non-public members of {@code AccessibleObject} or {@link Module}. |
| * |
| * <p>If there is a security manager, its |
| * {@code checkPermission} method is first called with a |
| * {@code ReflectPermission("suppressAccessChecks")} permission. |
| * |
| * <p>A {@code SecurityException} is also thrown if any of the elements of |
| * the input {@code array} is a {@link java.lang.reflect.Constructor} |
| * object for the class {@code java.lang.Class} and {@code flag} is true. |
| * |
| * @param array the array of AccessibleObjects |
| * @param flag the new value for the {@code accessible} flag |
| * in each object |
| * @throws InaccessibleObjectException if access cannot be enabled |
| * @throws SecurityException if the request is denied. |
| * @see SecurityManager#checkPermission |
| * @see ReflectPermission |
| */ |
| @CallerSensitive |
| public static void setAccessible(AccessibleObject[] array, boolean flag) { |
| checkPermission(); |
| if (flag) { |
| Class<?> caller = Reflection.getCallerClass(); |
| array = array.clone(); |
| for (AccessibleObject ao : array) { |
| ao.checkCanSetAccessible(caller); |
| } |
| } |
| for (AccessibleObject ao : array) { |
| ao.setAccessible0(flag); |
| } |
| } |
| |
| /** |
| * Set the {@code accessible} flag for this object to |
| * the indicated boolean value. A value of {@code true} indicates that |
| * the reflected object should suppress Java language access |
| * checking when it is used. A value of {@code false} indicates |
| * that the reflected object should enforce Java language access checks |
| * while assuming readability (as noted in the class description). |
| * |
| * <p>This method cannot be used to enable access to an object that is a |
| * {@link Member member} of a class in a different module to the caller and |
| * where the class is in a package that is not exported to the caller's |
| * module. Additionally, this method cannot be used to enable access to |
| * non-public members of {@code AccessibleObject} or {@link Module}. |
| * |
| * <p>If there is a security manager, its |
| * {@code checkPermission} method is first called with a |
| * {@code ReflectPermission("suppressAccessChecks")} permission. |
| * |
| * @param flag the new value for the {@code accessible} flag |
| * @throws InaccessibleObjectException if access cannot be enabled |
| * @throws SecurityException if the request is denied |
| * @see SecurityManager#checkPermission |
| * @see ReflectPermission |
| */ |
| public void setAccessible(boolean flag) { |
| AccessibleObject.checkPermission(); |
| setAccessible0(flag); |
| } |
| |
| void setAccessible0(boolean flag) { |
| this.override = flag; |
| } |
| |
| /** |
| * If the given AccessibleObject is a {@code Constructor}, {@code Method} |
| * or {@code Field} then checks that its declaring class is in a package |
| * that can be accessed by the given caller of setAccessible. |
| */ |
| void checkCanSetAccessible(Class<?> caller) { |
| // do nothing, needs to be overridden by Constructor, Method, Field |
| } |
| |
| void checkCanSetAccessible(Class<?> caller, Class<?> declaringClass) { |
| Module callerModule = caller.getModule(); |
| Module declaringModule = declaringClass.getModule(); |
| |
| if (callerModule != declaringModule |
| && callerModule != Object.class.getModule()) { |
| |
| // check exports to target module |
| String pn = packageName(declaringClass); |
| if (!declaringModule.isExported(pn, callerModule)) { |
| String msg = "Unable to make member of " |
| + declaringClass + " accessible: " |
| + declaringModule + " does not export " |
| + pn + " to " + callerModule; |
| Reflection.throwInaccessibleObjectException(msg); |
| } |
| |
| } |
| |
| if (declaringClass == Module.class |
| || declaringClass == AccessibleObject.class) { |
| int modifiers; |
| if (this instanceof Executable) { |
| modifiers = ((Executable) this).getModifiers(); |
| } else { |
| modifiers = ((Field) this).getModifiers(); |
| } |
| if (!Modifier.isPublic(modifiers)) { |
| String msg = "Cannot make a non-public member of " |
| + declaringClass + " accessible"; |
| Reflection.throwInaccessibleObjectException(msg); |
| } |
| } |
| } |
| |
| /** |
| * Returns the package name of the given class. |
| */ |
| private static String packageName(Class<?> c) { |
| while (c.isArray()) { |
| c = c.getComponentType(); |
| } |
| String pn = c.getPackageName(); |
| return (pn != null) ? pn : ""; |
| } |
| |
| /** |
| * Get the value of the {@code accessible} flag for this object. |
| * |
| * @return the value of the object's {@code accessible} flag |
| */ |
| public boolean isAccessible() { |
| return override; |
| } |
| |
| /** |
| * Constructor: only used by the Java Virtual Machine. |
| */ |
| protected AccessibleObject() {} |
| |
| // Indicates whether language-level access checks are overridden |
| // by this object. Initializes to "false". This field is used by |
| // Field, Method, and Constructor. |
| // |
| // NOTE: for security purposes, this field must not be visible |
| // outside this package. |
| boolean override; |
| |
| // Reflection factory used by subclasses for creating field, |
| // method, and constructor accessors. Note that this is called |
| // very early in the bootstrapping process. |
| static final ReflectionFactory reflectionFactory = |
| AccessController.doPrivileged( |
| new ReflectionFactory.GetReflectionFactoryAction()); |
| |
| /** |
| * @throws NullPointerException {@inheritDoc} |
| * @since 1.5 |
| */ |
| public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { |
| throw new AssertionError("All subclasses should override this method"); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * @throws NullPointerException {@inheritDoc} |
| * @since 1.5 |
| */ |
| @Override |
| public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) { |
| return AnnotatedElement.super.isAnnotationPresent(annotationClass); |
| } |
| |
| /** |
| * @throws NullPointerException {@inheritDoc} |
| * @since 1.8 |
| */ |
| @Override |
| public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) { |
| throw new AssertionError("All subclasses should override this method"); |
| } |
| |
| /** |
| * @since 1.5 |
| */ |
| public Annotation[] getAnnotations() { |
| return getDeclaredAnnotations(); |
| } |
| |
| /** |
| * @throws NullPointerException {@inheritDoc} |
| * @since 1.8 |
| */ |
| @Override |
| public <T extends Annotation> T getDeclaredAnnotation(Class<T> annotationClass) { |
| // Only annotations on classes are inherited, for all other |
| // objects getDeclaredAnnotation is the same as |
| // getAnnotation. |
| return getAnnotation(annotationClass); |
| } |
| |
| /** |
| * @throws NullPointerException {@inheritDoc} |
| * @since 1.8 |
| */ |
| @Override |
| public <T extends Annotation> T[] getDeclaredAnnotationsByType(Class<T> annotationClass) { |
| // Only annotations on classes are inherited, for all other |
| // objects getDeclaredAnnotationsByType is the same as |
| // getAnnotationsByType. |
| return getAnnotationsByType(annotationClass); |
| } |
| |
| /** |
| * @since 1.5 |
| */ |
| public Annotation[] getDeclaredAnnotations() { |
| throw new AssertionError("All subclasses should override this method"); |
| } |
| |
| |
| // Shared access checking logic. |
| |
| // For non-public members or members in package-private classes, |
| // it is necessary to perform somewhat expensive security checks. |
| // If the security check succeeds for a given class, it will |
| // always succeed (it is not affected by the granting or revoking |
| // of permissions); we speed up the check in the common case by |
| // remembering the last Class for which the check succeeded. |
| // |
| // The simple security check for Constructor is to see if |
| // the caller has already been seen, verified, and cached. |
| // (See also Class.newInstance(), which uses a similar method.) |
| // |
| // A more complicated security check cache is needed for Method and Field |
| // The cache can be either null (empty cache), a 2-array of {caller,target}, |
| // or a caller (with target implicitly equal to this.clazz). |
| // In the 2-array case, the target is always different from the clazz. |
| volatile Object securityCheckCache; |
| |
| void checkAccess(Class<?> caller, Class<?> clazz, Object obj, int modifiers) |
| throws IllegalAccessException |
| { |
| if (caller == clazz) { // quick check |
| return; // ACCESS IS OK |
| } |
| Object cache = securityCheckCache; // read volatile |
| Class<?> targetClass = clazz; |
| if (obj != null |
| && Modifier.isProtected(modifiers) |
| && ((targetClass = obj.getClass()) != clazz)) { |
| // Must match a 2-list of { caller, targetClass }. |
| if (cache instanceof Class[]) { |
| Class<?>[] cache2 = (Class<?>[]) cache; |
| if (cache2[1] == targetClass && |
| cache2[0] == caller) { |
| return; // ACCESS IS OK |
| } |
| // (Test cache[1] first since range check for [1] |
| // subsumes range check for [0].) |
| } |
| } else if (cache == caller) { |
| // Non-protected case (or obj.class == this.clazz). |
| return; // ACCESS IS OK |
| } |
| |
| // If no return, fall through to the slow path. |
| slowCheckMemberAccess(caller, clazz, obj, modifiers, targetClass); |
| } |
| |
| // Keep all this slow stuff out of line: |
| void slowCheckMemberAccess(Class<?> caller, Class<?> clazz, Object obj, int modifiers, |
| Class<?> targetClass) |
| throws IllegalAccessException |
| { |
| Reflection.ensureMemberAccess(caller, clazz, obj, modifiers); |
| |
| // Success: Update the cache. |
| Object cache = ((targetClass == clazz) |
| ? caller |
| : new Class<?>[] { caller, targetClass }); |
| |
| // Note: The two cache elements are not volatile, |
| // but they are effectively final. The Java memory model |
| // guarantees that the initializing stores for the cache |
| // elements will occur before the volatile write. |
| securityCheckCache = cache; // write volatile |
| } |
| } |