/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.javascript;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.lang.reflect.UndeclaredThrowableException;
import java.net.URL;
import java.security.AccessController;
import java.security.CodeSource;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.security.SecureClassLoader;
import java.util.Map;
import java.util.WeakHashMap;
/**
* @author Attila Szegedi
*/
public abstract class SecureCaller
{
private static final byte[] secureCallerImplBytecode = loadBytecode();
// We're storing a CodeSource -> (ClassLoader -> SecureRenderer), since we
// need to have one renderer per class loader. We're using weak hash maps
// and soft references all the way, since we don't want to interfere with
// cleanup of either CodeSource or ClassLoader objects.
private static final Map<CodeSource,Map<ClassLoader,SoftReference<SecureCaller>>>
callers =
new WeakHashMap<CodeSource,Map<ClassLoader,SoftReference<SecureCaller>>>();
public abstract Object call(Callable callable, Context cx,
Scriptable scope, Scriptable thisObj, Object[] args);
/**
* Call the specified callable using a protection domain belonging to the
* specified code source.
*/
static Object callSecurely(final CodeSource codeSource, Callable callable,
Context cx, Scriptable scope, Scriptable thisObj, Object[] args)
{
final Thread thread = Thread.currentThread();
// Run in doPrivileged as we might be checked for "getClassLoader"
// runtime permission
final ClassLoader classLoader = (ClassLoader)AccessController.doPrivileged(
new PrivilegedAction<Object>() {
public Object run() {
return thread.getContextClassLoader();
}
});
Map<ClassLoader,SoftReference<SecureCaller>> classLoaderMap;
synchronized(callers)
{
classLoaderMap = callers.get(codeSource);
if(classLoaderMap == null)
{
classLoaderMap = new WeakHashMap<ClassLoader,SoftReference<SecureCaller>>();
callers.put(codeSource, classLoaderMap);
}
}
SecureCaller caller;
synchronized(classLoaderMap)
{
SoftReference<SecureCaller> ref = classLoaderMap.get(classLoader);
if (ref != null) {
caller = ref.get();
} else {
caller = null;
}
if (caller == null) {
try
{
// Run in doPrivileged as we'll be checked for
// "createClassLoader" runtime permission
caller = (SecureCaller)AccessController.doPrivileged(
new PrivilegedExceptionAction<Object>()
{
public Object run() throws Exception
{
ClassLoader effectiveClassLoader;
Class<?> thisClass = getClass();
if(classLoader.loadClass(thisClass.getName()) != thisClass) {
effectiveClassLoader = thisClass.getClassLoader();
} else {
effectiveClassLoader = classLoader;
}
SecureClassLoaderImpl secCl =
new SecureClassLoaderImpl(effectiveClassLoader);
Class<?> c = secCl.defineAndLinkClass(
SecureCaller.class.getName() + "Impl",
secureCallerImplBytecode, codeSource);
return c.newInstance();
}
});
classLoaderMap.put(classLoader, new SoftReference<SecureCaller>(caller));
}
catch(PrivilegedActionException ex)
{
throw new UndeclaredThrowableException(ex.getCause());
}
}
}
return caller.call(callable, cx, scope, thisObj, args);
}
private static class SecureClassLoaderImpl extends SecureClassLoader
{
SecureClassLoaderImpl(ClassLoader parent)
{
super(parent);
}
Class<?> defineAndLinkClass(String name, byte[] bytes, CodeSource cs)
{
Class<?> cl = defineClass(name, bytes, 0, bytes.length, cs);
resolveClass(cl);
return cl;
}
}
private static byte[] loadBytecode()
{
return (byte[])AccessController.doPrivileged(new PrivilegedAction<Object>()
{
public Object run()
{
return loadBytecodePrivileged();
}
});
}
private static byte[] loadBytecodePrivileged()
{
URL url = SecureCaller.class.getResource("SecureCallerImpl.clazz");
try
{
InputStream in = url.openStream();
try
{
ByteArrayOutputStream bout = new ByteArrayOutputStream();
for(;;)
{
int r = in.read();
if(r == -1)
{
return bout.toByteArray();
}
bout.write(r);
}
}
finally
{
in.close();
}
}
catch(IOException e)
{
throw new UndeclaredThrowableException(e);
}
}
}