BundleScrubber.java

/*
 * Copyright 2013 two forty four a.m. LLC <http://www.twofortyfouram.com>
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * <http://www.apache.org/licenses/LICENSE-2.0>
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and limitations under the License.
 */

package fero.taskerplugin.dismissalarm.utilities;

import android.content.Intent;
import android.os.Bundle;

/**
 * Helper class to scrub Bundles of invalid extras. This is a workaround for an
 * Android bug: <http://code.google.com/p/android/issues/detail?id=16006>.
 */
public final class BundleScrubber {

	/**
	 * Scrubs Intents for private serializable subclasses in the Intent extras.
	 * If the Intent's extras contain a private serializable subclass, the
	 * Bundle is cleared. The Bundle will not be set to null. If the Bundle is
	 * null, has no extras, or the extras do not contain a private serializable
	 * subclass, the Bundle is not mutated.
	 * 
	 * @param intent {@code Intent} to scrub. This parameter may be mutated if
	 *            scrubbing is necessary. This parameter may be null.
	 * @return true if the Intent was scrubbed, false if the Intent was not
	 *         modified.
	 */
	public static boolean scrub(final Intent intent) {
		if (null == intent) {
			return false;
		}

		return scrub(intent.getExtras());
	}

	/**
	 * Scrubs Bundles for private serializable subclasses in the extras. If the
	 * Bundle's extras contain a private serializable subclass, the Bundle is
	 * cleared. If the Bundle is null, has no extras, or the extras do not
	 * contain a private serializable subclass, the Bundle is not mutated.
	 * 
	 * @param bundle {@code Bundle} to scrub. This parameter may be mutated if
	 *            scrubbing is necessary. This parameter may be null.
	 * @return true if the Bundle was scrubbed, false if the Bundle was not
	 *         modified.
	 */
	public static boolean scrub(final Bundle bundle) {
		if (null == bundle) {
			return false;
		}

		/*
		 * Note: This is a hack to work around a private serializable
		 * classloader attack
		 */
		try {
			// if a private serializable exists, this will throw an exception
			bundle.containsKey(null);
		} catch (final Exception e) {
			bundle.clear();
			return true;
		}

		return false;
	}
}