/*
* @(#)SecureClassLoader.java 1.85 04/05/05
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.security;
import java.util.HashMap;
import java.util.ArrayList;
import java.net.URL;
import sun.security.util.Debug;
/**
* This class extends ClassLoader with additional support for defining
* classes with an associated code source and permissions which are
* retrieved by the system policy by default.
*
* @version 1.85, 05/05/04
* @author Li Gong
* @author Roland Schemers
*/
public class SecureClassLoader extends ClassLoader {
/*
* If initialization succeed this is set to true and security checks will
* succeed. Otherwise the object is not initialized and the object is
* useless.
*/
private boolean initialized = false;
// HashMap that maps CodeSource to ProtectionDomain
private HashMap pdcache = new HashMap(11);
private static final Debug debug = Debug.getInstance("scl");
/**
* Creates a new SecureClassLoader using the specified parent
* class loader for delegation.
*
* <p>If there is a security manager, this method first
* calls the security manager's <code>checkCreateClassLoader</code>
* method to ensure creation of a class loader is allowed.
* <p>
* @param parent the parent ClassLoader
* @exception SecurityException if a security manager exists and its
* <code>checkCreateClassLoader</code> method doesn't allow
* creation of a class loader.
* @see SecurityManager#checkCreateClassLoader
*/
protected SecureClassLoader(ClassLoader parent) {
super(parent);
// this is to make the stack depth consistent with 1.1
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkCreateClassLoader();
}
initialized = true;
}
/**
* Creates a new SecureClassLoader using the default parent class
* loader for delegation.
*
* <p>If there is a security manager, this method first
* calls the security manager's <code>checkCreateClassLoader</code>
* method to ensure creation of a class loader is allowed.
*
* @exception SecurityException if a security manager exists and its
* <code>checkCreateClassLoader</code> method doesn't allow
* creation of a class loader.
* @see SecurityManager#checkCreateClassLoader
*/
protected SecureClassLoader() {
super();
// this is to make the stack depth consistent with 1.1
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkCreateClassLoader();
}
initialized = true;
}
/**
* Converts an array of bytes into an instance of class Class,
* with an optional CodeSource. Before the
* class can be used it must be resolved.
* <p>
* If a non-null CodeSource is supplied a ProtectionDomain is
* constructed and associated with the class being defined.
* <p>
* @param name the expected name of the class, or <code>null</code>
* if not known, using '.' and not '/' as the separator
* and without a trailing ".class" suffix.
* @param b the bytes that make up the class data. The bytes in
* positions <code>off</code> through <code>off+len-1</code>
* should have the format of a valid class file as defined
* by the
* <a href="http://java.sun.com/docs/books/vmspec/">Java
* Virtual Machine Specification</a>.
* @param off the start offset in <code>b</code> of the class data
* @param len the length of the class data
* @param cs the associated CodeSource, or <code>null</code> if none
* @return the <code>Class</code> object created from the data,
* and optional CodeSource.
* @exception ClassFormatError if the data did not contain a valid class
* @exception IndexOutOfBoundsException if either <code>off</code> or
* <code>len</code> is negative, or if
* <code>off+len</code> is greater than <code>b.length</code>.
*
* @exception SecurityException if an attempt is made to add this class
* to a package that contains classes that were signed by
* a different set of certificates than this class, or if
* the class name begins with "java.".
*/
protected final Class<?> defineClass(String name,
byte[] b, int off, int len,
CodeSource cs)
{
if (cs == null)
return defineClass(name, b, off, len);
else
return defineClass(name, b, off, len, getProtectionDomain(cs));
}
/**
* Converts a {@link java.nio.ByteBuffer <tt>ByteBuffer</tt>}
* into an instance of class <tt>Class</tt>, with an optional CodeSource.
* Before the class can be used it must be resolved.
* <p>
* If a non-null CodeSource is supplied a ProtectionDomain is
* constructed and associated with the class being defined.
* <p>
* @param name the expected name of the class, or <code>null</code>
* if not known, using '.' and not '/' as the separator
* and without a trailing ".class" suffix.
* @param b the bytes that make up the class data. The bytes from positions
* <tt>b.position()</tt> through <tt>b.position() + b.limit() -1</tt>
* should have the format of a valid class file as defined by the
* <a href="http://java.sun.com/docs/books/vmspec/">Java Virtual
* Machine Specification</a>.
* @param cs the associated CodeSource, or <code>null</code> if none
* @return the <code>Class</code> object created from the data,
* and optional CodeSource.
* @exception ClassFormatError if the data did not contain a valid class
* @exception SecurityException if an attempt is made to add this class
* to a package that contains classes that were signed by
* a different set of certificates than this class, or if
* the class name begins with "java.".
*
* @since 1.5
*/
protected final Class<?> defineClass(String name, java.nio.ByteBuffer b,
CodeSource cs)
{
if (cs == null)
return defineClass(name, b, (ProtectionDomain)null);
else
return defineClass(name, b, getProtectionDomain(cs));
}
/**
* Returns the permissions for the given CodeSource object.
* <p>
* This method is invoked by the defineClass method which takes
* a CodeSource as an argument when it is constructing the
* ProtectionDomain for the class being defined.
* <p>
* @param codesource the codesource.
*
* @return the permissions granted to the codesource.
*
*/
protected PermissionCollection getPermissions(CodeSource codesource)
{
check();
return new Permissions(); // ProtectionDomain defers the binding
}
/*
* Returned cached ProtectionDomain for the specified CodeSource.
*/
private ProtectionDomain getProtectionDomain(CodeSource cs) {
if (cs == null)
return null;
ProtectionDomain pd = null;
synchronized (pdcache) {
pd = (ProtectionDomain)pdcache.get(cs);
if (pd == null) {
PermissionCollection perms = getPermissions(cs);
pd = new ProtectionDomain(cs, perms, this, null);
if (pd != null) {
pdcache.put(cs, pd);
if (debug != null) {
debug.println(" getPermissions "+ pd);
debug.println("");
}
}
}
}
return pd;
}
/*
* Check to make sure the class loader has been initialized.
*/
private void check() {
if (!initialized) {
throw new SecurityException("ClassLoader object not initialized");
}
}
}
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