Properly protect cell location.

Test: manual

bug:38489777
diff --git a/src/com/android/phone/LocationAccessPolicy.java b/src/com/android/phone/LocationAccessPolicy.java
new file mode 100644
index 0000000..9f863a3
--- /dev/null
+++ b/src/com/android/phone/LocationAccessPolicy.java
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2017 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 com.android.phone;
+
+import android.Manifest;
+import android.annotation.NonNull;
+import android.annotation.UserIdInt;
+import android.app.ActivityManager;
+import android.app.AppOpsManager;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.content.pm.UserInfo;
+import android.os.Build;
+import android.os.UserHandle;
+import android.os.UserManager;
+import android.provider.Settings;
+
+import java.util.List;
+
+/**
+ * Helper for performing location access checks.
+ */
+final class LocationAccessPolicy {
+
+    private LocationAccessPolicy() {
+        /* do nothing - hide ctor */
+    }
+
+    /**
+     * API to determine if the caller has permissions to get cell location.
+     *
+     * @param pkgName Package name of the application requesting access
+     * @param uid The uid of the package
+     * @return boolean true or false if permissions is granted
+     */
+    static boolean canAccessCellLocation(@NonNull Context context, @NonNull String pkgName,
+            int uid) throws SecurityException {
+        context.getSystemService(AppOpsManager.class).checkPackage(uid, pkgName);
+        // We always require the location permission and also require the
+        // location mode to be on for non-legacy apps. Legacy apps are
+        // required to be in the foreground to at least mitigate the case
+        // where a legacy app the user is not using tracks their location.
+        if (!hasUidLocationPermission(context, pkgName, uid)
+                || (!isLocationModeEnabled(context, UserHandle.getUserId(uid)))
+                        && !isLegacyForeground(context, pkgName)) {
+            return false;
+        }
+        // If the user or profile is current, permission is granted.
+        // Otherwise, uid must have INTERACT_ACROSS_USERS_FULL permission.
+        return isCurrentProfile(context, uid) || checkInteractAcrossUsersFull(context);
+    }
+
+    private static boolean isLocationModeEnabled(@NonNull Context context, @UserIdInt int userId) {
+        return Settings.Secure.getIntForUser(context.getContentResolver(),
+                Settings.Secure.LOCATION_MODE, Settings.Secure.LOCATION_MODE_OFF, userId)
+                != Settings.Secure.LOCATION_MODE_OFF;
+    }
+
+    private static boolean isLegacyForeground(@NonNull Context context, @NonNull String pkgName) {
+        return isLegacyVersion(context, pkgName) && isForegroundApp(context, pkgName);
+    }
+
+    private static boolean isLegacyVersion(@NonNull Context context, @NonNull String pkgName) {
+        try {
+            if (context.getPackageManager().getApplicationInfo(pkgName, 0)
+                    .targetSdkVersion <= Build.VERSION_CODES.O) {
+                return true;
+            }
+        } catch (PackageManager.NameNotFoundException e) {
+            // In case of exception, assume known app (more strict checking)
+            // Note: This case will never happen since checkPackage is
+            // called to verify validity before checking app's version.
+        }
+        return false;
+    }
+
+    private static boolean isForegroundApp(@NonNull Context context, @NonNull String pkgName) {
+        final ActivityManager am = context.getSystemService(ActivityManager.class);
+        final List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(1);
+        if (!tasks.isEmpty()) {
+            return pkgName.equals(tasks.get(0).topActivity.getPackageName());
+        }
+        return false;
+    }
+
+    private static boolean checkInteractAcrossUsersFull(@NonNull Context context) {
+        return context.checkCallingOrSelfPermission(
+                android.Manifest.permission.INTERACT_ACROSS_USERS_FULL)
+                == PackageManager.PERMISSION_GRANTED;
+    }
+
+    private static boolean hasUidLocationPermission(@NonNull Context context,
+            @NonNull String pkgName, int uid) {
+        // Grating ACCESS_FINE_LOCATION to an app automatically grants it ACCESS_COARSE_LOCATION.
+        if ((context.checkCallingOrSelfPermission(
+                Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED)) {
+            final int opCode = AppOpsManager.permissionToOpCode(
+                    Manifest.permission.ACCESS_COARSE_LOCATION);
+            if (opCode != AppOpsManager.OP_NONE) {
+                return context.getSystemService(AppOpsManager.class).noteOp(opCode, uid, pkgName)
+                        == AppOpsManager.MODE_ALLOWED;
+            }
+        }
+        return false;
+    }
+
+    private static boolean isCurrentProfile(@NonNull Context context, int uid) {
+        final int currentUser = ActivityManager.getCurrentUser();
+        final int callingUserId = UserHandle.getUserId(uid);
+        if (callingUserId == currentUser) {
+            return true;
+        } else {
+            List<UserInfo> userProfiles = context.getSystemService(
+                    UserManager.class).getProfiles(currentUser);
+            for (UserInfo user: userProfiles) {
+                if (user.id == callingUserId) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+}
diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index de60c61..2f7c203 100644
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -19,7 +19,6 @@
 import static com.android.internal.telephony.PhoneConstants.SUBSCRIPTION_KEY;
 
 import android.Manifest.permission;
-import android.app.ActivityManager;
 import android.app.AppOpsManager;
 import android.app.PendingIntent;
 import android.content.ComponentName;
@@ -1635,47 +1634,23 @@
 
     @Override
     public Bundle getCellLocation(String callingPackage) {
-        enforceFineOrCoarseLocationPermission("getCellLocation");
-
-        // OP_COARSE_LOCATION controls both fine and coarse location.
-        if (mAppOps.noteOp(AppOpsManager.OP_COARSE_LOCATION, Binder.getCallingUid(),
-                callingPackage) != AppOpsManager.MODE_ALLOWED) {
-            log("getCellLocation: returning null; mode != allowed");
+        if (!LocationAccessPolicy.canAccessCellLocation(mPhone.getContext(),
+                callingPackage, Binder.getCallingUid())) {
             return null;
         }
 
-        if (checkIfCallerIsSelfOrForegroundUser() ||
-                checkCallerInteractAcrossUsersFull()) {
-            if (DBG_LOC) log("getCellLocation: is active user");
-            Bundle data = new Bundle();
-            Phone phone = getPhone(mSubscriptionController.getDefaultDataSubId());
-            if (phone == null) {
-                return null;
-            }
-
-            WorkSource workSource = getWorkSource(null, Binder.getCallingUid());
-            phone.getCellLocation(workSource).fillInNotifierBundle(data);
-            return data;
-        } else {
-            log("getCellLocation: suppress non-active user");
+        if (DBG_LOC) log("getCellLocation: is active user");
+        Bundle data = new Bundle();
+        Phone phone = getPhone(mSubscriptionController.getDefaultDataSubId());
+        if (phone == null) {
             return null;
         }
-    }
 
-    private void enforceFineOrCoarseLocationPermission(String message) {
-        try {
-            mApp.enforceCallingOrSelfPermission(
-                    android.Manifest.permission.ACCESS_FINE_LOCATION, null);
-        } catch (SecurityException e) {
-            // If we have ACCESS_FINE_LOCATION permission, skip the check for ACCESS_COARSE_LOCATION
-            // A failure should throw the SecurityException from ACCESS_COARSE_LOCATION since this
-            // is the weaker precondition
-            mApp.enforceCallingOrSelfPermission(
-                    android.Manifest.permission.ACCESS_COARSE_LOCATION, message);
-        }
+        WorkSource workSource = getWorkSource(null, Binder.getCallingUid());
+        phone.getCellLocation(workSource).fillInNotifierBundle(data);
+        return data;
     }
 
-
     @Override
     public void enableLocationUpdates() {
         enableLocationUpdatesForSubscriber(getDefaultSubscription());
@@ -1709,11 +1684,8 @@
     @Override
     @SuppressWarnings("unchecked")
     public List<NeighboringCellInfo> getNeighboringCellInfo(String callingPackage) {
-        enforceFineOrCoarseLocationPermission("getNeighboringCellInfo");
-
-        // OP_COARSE_LOCATION controls both fine and coarse location.
-        if (mAppOps.noteOp(AppOpsManager.OP_COARSE_LOCATION, Binder.getCallingUid(),
-                callingPackage) != AppOpsManager.MODE_ALLOWED) {
+        if (!LocationAccessPolicy.canAccessCellLocation(mPhone.getContext(),
+                callingPackage, Binder.getCallingUid())) {
             return null;
         }
 
@@ -1722,52 +1694,37 @@
             return null;
         }
 
-        if (checkIfCallerIsSelfOrForegroundUser() ||
-                checkCallerInteractAcrossUsersFull()) {
-            if (DBG_LOC) log("getNeighboringCellInfo: is active user");
+        if (DBG_LOC) log("getNeighboringCellInfo: is active user");
 
-            ArrayList<NeighboringCellInfo> cells = null;
+        ArrayList<NeighboringCellInfo> cells = null;
 
-            WorkSource workSource = getWorkSource(null, Binder.getCallingUid());
-            try {
-                cells = (ArrayList<NeighboringCellInfo>) sendRequest(
-                        CMD_HANDLE_NEIGHBORING_CELL, workSource,
-                        SubscriptionManager.INVALID_SUBSCRIPTION_ID);
-            } catch (RuntimeException e) {
-                Log.e(LOG_TAG, "getNeighboringCellInfo " + e);
-            }
-            return cells;
-        } else {
-            if (DBG_LOC) log("getNeighboringCellInfo: suppress non-active user");
-            return null;
+        WorkSource workSource = getWorkSource(null, Binder.getCallingUid());
+        try {
+            cells = (ArrayList<NeighboringCellInfo>) sendRequest(
+                    CMD_HANDLE_NEIGHBORING_CELL, workSource,
+                    SubscriptionManager.INVALID_SUBSCRIPTION_ID);
+        } catch (RuntimeException e) {
+            Log.e(LOG_TAG, "getNeighboringCellInfo " + e);
         }
+        return cells;
     }
 
 
     @Override
     public List<CellInfo> getAllCellInfo(String callingPackage) {
-        enforceFineOrCoarseLocationPermission("getAllCellInfo");
-
-        // OP_COARSE_LOCATION controls both fine and coarse location.
-        if (mAppOps.noteOp(AppOpsManager.OP_COARSE_LOCATION, Binder.getCallingUid(),
-                callingPackage) != AppOpsManager.MODE_ALLOWED) {
+        if (!LocationAccessPolicy.canAccessCellLocation(mPhone.getContext(),
+                callingPackage, Binder.getCallingUid())) {
             return null;
         }
 
-        if (checkIfCallerIsSelfOrForegroundUser() ||
-                checkCallerInteractAcrossUsersFull()) {
-            if (DBG_LOC) log("getAllCellInfo: is active user");
-            WorkSource workSource = getWorkSource(null, Binder.getCallingUid());
-            List<CellInfo> cellInfos = new ArrayList<CellInfo>();
-            for (Phone phone : PhoneFactory.getPhones()) {
-                final List<CellInfo> info = phone.getAllCellInfo(workSource);
-                if (info != null) cellInfos.addAll(info);
-            }
-            return cellInfos;
-        } else {
-            if (DBG_LOC) log("getAllCellInfo: suppress non-active user");
-            return null;
+        if (DBG_LOC) log("getAllCellInfo: is active user");
+        WorkSource workSource = getWorkSource(null, Binder.getCallingUid());
+        List<CellInfo> cellInfos = new ArrayList<CellInfo>();
+        for (Phone phone : PhoneFactory.getPhones()) {
+            final List<CellInfo> info = phone.getAllCellInfo(workSource);
+            if (info != null) cellInfos.addAll(info);
         }
+        return cellInfos;
     }
 
     @Override
@@ -1809,47 +1766,6 @@
     //
 
     /**
-     * Returns true if the caller holds INTERACT_ACROSS_USERS_FULL.
-     */
-    private boolean checkCallerInteractAcrossUsersFull() {
-        return mPhone.getContext().checkCallingOrSelfPermission(
-                android.Manifest.permission.INTERACT_ACROSS_USERS_FULL)
-                == PackageManager.PERMISSION_GRANTED;
-    }
-
-    private static boolean checkIfCallerIsSelfOrForegroundUser() {
-        boolean ok;
-
-        boolean self = Binder.getCallingUid() == Process.myUid();
-        if (!self) {
-            // Get the caller's user id then clear the calling identity
-            // which will be restored in the finally clause.
-            int callingUser = UserHandle.getCallingUserId();
-            long ident = Binder.clearCallingIdentity();
-
-            try {
-                // With calling identity cleared the current user is the foreground user.
-                int foregroundUser = ActivityManager.getCurrentUser();
-                ok = (foregroundUser == callingUser);
-                if (DBG_LOC) {
-                    log("checkIfCallerIsSelfOrForegoundUser: foregroundUser=" + foregroundUser
-                            + " callingUser=" + callingUser + " ok=" + ok);
-                }
-            } catch (Exception ex) {
-                if (DBG_LOC) loge("checkIfCallerIsSelfOrForegoundUser: Exception ex=" + ex);
-                ok = false;
-            } finally {
-                Binder.restoreCallingIdentity(ident);
-            }
-        } else {
-            if (DBG_LOC) log("checkIfCallerIsSelfOrForegoundUser: is self");
-            ok = true;
-        }
-        if (DBG_LOC) log("checkIfCallerIsSelfOrForegoundUser: ret=" + ok);
-        return ok;
-    }
-
-    /**
      * Make sure the caller has the MODIFY_PHONE_STATE permission.
      *
      * @throws SecurityException if the caller does not have the required permission