Signal-Android/src/org/thoughtcrime/securesms/util/MemoryCleaner.java

90 wiersze
2.9 KiB
Java

/**
* Copyright (C) 2011 Whisper Systems
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.thoughtcrime.securesms.util;
import java.lang.reflect.Field;
import java.util.Arrays;
import javax.crypto.spec.SecretKeySpec;
import org.thoughtcrime.securesms.crypto.MasterSecret;
import android.util.Log;
/**
* This is not straightforward in Java, but this class makes
* a best-effort attempt to clean up memory in immutable objects.
*
* @author Moxie Marlinspike
*/
public class MemoryCleaner {
// XXX This is basically not happening for now.
// The problem is that now secrets are moving
// through both Intents and binder calls, which
// means sometimes they're shared memory and sometimes
// they're not. We're going to need to do a lot more
// work in order to accurately keep track of when to
// wipe this within an Activity lifecycle. =(
public static void clean(MasterSecret masterSecret) {
// if (masterSecret == null)
// return;
//
// try {
// SecretKeySpec cipherKey = masterSecret.getEncryptionKey();
// SecretKeySpec macKey = masterSecret.getMacKey();
//
// Field keyField = SecretKeySpec.class.getDeclaredField("key");
// keyField.setAccessible(true);
//
// byte[] cipherKeyField = (byte[]) keyField.get(cipherKey);
// byte[] macKeyField = (byte[]) keyField.get(macKey);
//
// Arrays.fill(cipherKeyField, (byte)0x00);
// Arrays.fill(macKeyField, (byte)0x00);
//
// } catch (NoSuchFieldException nsfe) {
// Log.w("MemoryCleaner", nsfe);
// } catch (IllegalArgumentException e) {
// Log.w("MemoryCleaner", e);
// } catch (IllegalAccessException e) {
// Log.w("MemoryCleaner", e);
// }
}
public static void clean(String string) {
if (string == null)
return;
try {
Field charArrayField = String.class.getDeclaredField("value");
charArrayField.setAccessible(true);
char[] internalBuffer = (char[])charArrayField.get(string);
Arrays.fill(internalBuffer, 'A');
} catch (NoSuchFieldException nsfe) {
Log.w("MemoryCleaner", nsfe);
} catch (IllegalArgumentException e) {
Log.w("MemoryCleaner", e);
} catch (IllegalAccessException e) {
Log.w("MemoryCleaner", e);
}
}
}