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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License
     15  */
     16 
     17 package android.telephony;
     18 
     19 import android.Manifest;
     20 import android.annotation.NonNull;
     21 import android.annotation.UserIdInt;
     22 import android.app.ActivityManager;
     23 import android.app.AppOpsManager;
     24 import android.content.Context;
     25 import android.content.pm.PackageManager;
     26 import android.content.pm.UserInfo;
     27 import android.location.LocationManager;
     28 import android.os.Binder;
     29 import android.os.Process;
     30 import android.os.Trace;
     31 import android.os.UserHandle;
     32 import android.os.UserManager;
     33 import android.util.Log;
     34 
     35 import java.util.List;
     36 
     37 /**
     38  * Helper for performing location access checks.
     39  * @hide
     40  */
     41 public final class LocationAccessPolicy {
     42     private static final String LOG_TAG = LocationAccessPolicy.class.getSimpleName();
     43 
     44     /**
     45      * API to determine if the caller has permissions to get cell location.
     46      *
     47      * @param pkgName Package name of the application requesting access
     48      * @param uid The uid of the package
     49      * @param pid The pid of the package
     50      * @param throwOnDeniedPermission Whether to throw if the location permission is denied.
     51      * @return boolean true or false if permissions is granted
     52      */
     53     public static boolean canAccessCellLocation(@NonNull Context context, @NonNull String pkgName,
     54             int uid, int pid, boolean throwOnDeniedPermission) throws SecurityException {
     55         Trace.beginSection("TelephonyLohcationCheck");
     56         try {
     57             // Always allow the phone process to access location. This avoid breaking legacy code
     58             // that rely on public-facing APIs to access cell location, and it doesn't create a
     59             // info leak risk because the cell location is stored in the phone process anyway.
     60             if (uid == Process.PHONE_UID) {
     61                 return true;
     62             }
     63 
     64             // We always require the location permission and also require the
     65             // location mode to be on for non-legacy apps. Legacy apps are
     66             // required to be in the foreground to at least mitigate the case
     67             // where a legacy app the user is not using tracks their location.
     68             // Granting ACCESS_FINE_LOCATION to an app automatically grants it
     69             // ACCESS_COARSE_LOCATION.
     70             if (throwOnDeniedPermission) {
     71                 context.enforcePermission(Manifest.permission.ACCESS_COARSE_LOCATION,
     72                         pid, uid, "canAccessCellLocation");
     73             } else if (context.checkPermission(Manifest.permission.ACCESS_COARSE_LOCATION,
     74                     pid, uid) == PackageManager.PERMISSION_DENIED) {
     75                 return false;
     76             }
     77             final int opCode = AppOpsManager.permissionToOpCode(
     78                     Manifest.permission.ACCESS_COARSE_LOCATION);
     79             if (opCode != AppOpsManager.OP_NONE && context.getSystemService(AppOpsManager.class)
     80                     .noteOpNoThrow(opCode, uid, pkgName) != AppOpsManager.MODE_ALLOWED) {
     81                 return false;
     82             }
     83             if (!isLocationModeEnabled(context, UserHandle.getUserId(uid))) {
     84                 return false;
     85             }
     86             // If the user or profile is current, permission is granted.
     87             // Otherwise, uid must have INTERACT_ACROSS_USERS_FULL permission.
     88             return isCurrentProfile(context, uid) || checkInteractAcrossUsersFull(context);
     89         } finally {
     90             Trace.endSection();
     91         }
     92     }
     93 
     94     private static boolean isLocationModeEnabled(@NonNull Context context, @UserIdInt int userId) {
     95         LocationManager locationManager = context.getSystemService(LocationManager.class);
     96         if (locationManager == null) {
     97             Log.w(LOG_TAG, "Couldn't get location manager, denying location access");
     98             return false;
     99         }
    100         return locationManager.isLocationEnabledForUser(UserHandle.of(userId));
    101     }
    102 
    103     private static boolean checkInteractAcrossUsersFull(@NonNull Context context) {
    104         return context.checkCallingOrSelfPermission(
    105                 android.Manifest.permission.INTERACT_ACROSS_USERS_FULL)
    106                 == PackageManager.PERMISSION_GRANTED;
    107     }
    108 
    109     private static boolean isCurrentProfile(@NonNull Context context, int uid) {
    110         long token = Binder.clearCallingIdentity();
    111         try {
    112             final int currentUser = ActivityManager.getCurrentUser();
    113             final int callingUserId = UserHandle.getUserId(uid);
    114             if (callingUserId == currentUser) {
    115                 return true;
    116             } else {
    117                 List<UserInfo> userProfiles = context.getSystemService(
    118                         UserManager.class).getProfiles(currentUser);
    119                 for (UserInfo user : userProfiles) {
    120                     if (user.id == callingUserId) {
    121                         return true;
    122                     }
    123                 }
    124             }
    125             return false;
    126         } finally {
    127             Binder.restoreCallingIdentity(token);
    128         }
    129     }
    130 }
    131