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/*
* Copyright (C) 2014 The Android Open Source Project
* Copyright (c) 1997, 2014, 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.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--for 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.
*
* 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.
*
*
By default, a reflected object is not accessible.
*
* @see Field
* @see Method
* @see Constructor
* @see ReflectPermission
*
* @since 1.2
*/
public class AccessibleObject implements AnnotatedElement {
// Android-removed: Code associated with SecurityManager calls.
/*
/**
* The Permission object that is used to check whether a client
* has sufficient privilege to defeat Java language access
* control checks.
*
static final private java.security.Permission ACCESS_PERMISSION =
new ReflectPermission("suppressAccessChecks");
*/
/**
* Convenience method to set the {@code accessible} flag for an
* array of objects with a single security check (for efficiency).
*
*
First, if there is a security manager, its
* {@code checkPermission} method is called with a
* {@code ReflectPermission("suppressAccessChecks")} permission.
*
*
A {@code SecurityException} is raised if {@code flag} is
* {@code true} but accessibility of any of the elements of the input
* {@code array} may not be changed (for example, if the element
* object is a {@link Constructor} object for the class {@link
* java.lang.Class}). In the event of such a SecurityException, the
* accessibility of objects is set to {@code flag} for array elements
* upto (and excluding) the element for which the exception occurred; the
* accessibility of elements beyond (and including) the element for which
* the exception occurred is unchanged.
*
* @param array the array of AccessibleObjects
* @param flag the new value for the {@code accessible} flag
* in each object
* @throws SecurityException if the request is denied.
* @see SecurityManager#checkPermission
* @see java.lang.RuntimePermission
*/
public static void setAccessible(AccessibleObject[] array, boolean flag)
throws SecurityException {
// Android-removed: SecurityManager calls.
// SecurityManager sm = System.getSecurityManager();
// if (sm != null) sm.checkPermission(ACCESS_PERMISSION);
for (int i = 0; i < array.length; i++) {
setAccessible0(array[i], 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.
*
*
First, if there is a security manager, its
* {@code checkPermission} method is called with a
* {@code ReflectPermission("suppressAccessChecks")} permission.
*
*
A {@code SecurityException} is raised if {@code flag} is
* {@code true} but accessibility of this object may not be changed
* (for example, if this element object is a {@link Constructor} object for
* the class {@link java.lang.Class}).
*
*
A {@code SecurityException} is raised if this object is a {@link
* java.lang.reflect.Constructor} object for the class
* {@code java.lang.Class}, and {@code flag} is true.
*
* @param flag the new value for the {@code accessible} flag
* @throws SecurityException if the request is denied.
* @see SecurityManager#checkPermission
* @see java.lang.RuntimePermission
*/
public void setAccessible(boolean flag) throws SecurityException {
// Android-removed: SecurityManager calls.
// SecurityManager sm = System.getSecurityManager();
// if (sm != null) sm.checkPermission(ACCESS_PERMISSION);
setAccessible0(this, flag);
}
/* Check that you aren't exposing java.lang.Class. or sensitive
fields in java.lang.Class. */
private static void setAccessible0(AccessibleObject obj, boolean flag)
throws SecurityException
{
if (obj instanceof Constructor && flag == true) {
Constructor c = (Constructor)obj;
// BEGIN Android-changed: Disallow making Method & Field constructors accessible.
// if (c.getDeclaringClass() == Class.class) {
// throw new SecurityException("Cannot make a java.lang.Class" +
// " constructor accessible");
// }
Class clazz = c.getDeclaringClass();
if (clazz == Class.class) {
throw new SecurityException("Can not make a java.lang.Class" +
" constructor accessible");
} else if (clazz == Method.class) {
throw new SecurityException("Can not make a java.lang.reflect.Method" +
" constructor accessible");
} else if (clazz == Field.class) {
throw new SecurityException("Can not make a java.lang.reflect.Field" +
" constructor accessible");
}
// END Android-changed: Disallow making Method & Field constructors accessible.
}
obj.override = flag;
}
/**
* 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;
// Android-removed: reflectionFactory: it is not used on Android.
/*
// 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 sun.reflect.ReflectionFactory.GetReflectionFactoryAction());
*/
/**
* @throws NullPointerException {@inheritDoc}
* @since 1.5
*/
public T getAnnotation(Class annotationClass) {
throw new AssertionError("All subclasses should override this method");
}
/**
* {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @since 1.5
*/
@Override
public boolean isAnnotationPresent(Class annotationClass) {
return AnnotatedElement.super.isAnnotationPresent(annotationClass);
}
/**
* @throws NullPointerException {@inheritDoc}
* @since 1.8
*/
@Override
public T[] getAnnotationsByType(Class 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 getDeclaredAnnotation(Class 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[] getDeclaredAnnotationsByType(Class 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");
}
// BEGIN Android-removed: Shared access checking logic: Not used on Android.
/*
// 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
}
*/
// END Android-removed: Shared access checking logic: Not used on Android.
}