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      1 /*
      2  * Copyright (C) 2012 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.security.cts;
     18 
     19 import android.os.IBinder;
     20 import android.os.DeadObjectException;
     21 import android.os.TransactionTooLargeException;
     22 import android.platform.test.annotations.SecurityTest;
     23 import android.test.AndroidTestCase;
     24 import android.util.Log;
     25 
     26 import java.io.BufferedReader;
     27 import java.io.File;
     28 import java.io.FileInputStream;
     29 import java.io.FileOutputStream;
     30 import java.io.InputStreamReader;
     31 import java.lang.reflect.InvocationTargetException;
     32 import java.util.ArrayList;
     33 
     34 /**
     35  * Verifies that permissions are enforced on various system services.
     36  */
     37 @SecurityTest
     38 public class ServicePermissionsTest extends AndroidTestCase {
     39 
     40     private static final String TAG = "ServicePermissionsTest";
     41 
     42     private File mTempFile;
     43 
     44     @Override
     45     protected void setUp() throws Exception {
     46         super.setUp();
     47         mTempFile = new File(getContext().getCacheDir(), "CTS_DUMP");
     48     }
     49 
     50     @Override
     51     protected void tearDown() throws Exception {
     52         try {
     53             mTempFile.delete();
     54         } finally {
     55             super.tearDown();
     56         }
     57     }
     58 
     59     /**
     60      * Test that {@link IBinder#dump(java.io.FileDescriptor, String[])} on all
     61      * registered system services checks if caller holds
     62      * {@link android.Manifest.permission#DUMP} permission.
     63      */
     64     public void testDumpProtected() throws Exception {
     65 
     66         String[] services = null;
     67         try {
     68             services = (String[]) Class.forName("android.os.ServiceManager")
     69                     .getDeclaredMethod("listServices").invoke(null);
     70         } catch (ClassCastException e) {
     71         } catch (ClassNotFoundException e) {
     72         } catch (NoSuchMethodException e) {
     73         } catch (InvocationTargetException e) {
     74         } catch (IllegalAccessException e) {
     75         }
     76 
     77         if ((services == null) || (services.length == 0)) {
     78             Log.w(TAG, "No registered services, that's odd");
     79             return;
     80         }
     81 
     82         for (String service : services) {
     83             mTempFile.delete();
     84 
     85             IBinder serviceBinder = null;
     86             try {
     87                 serviceBinder = (IBinder) Class.forName("android.os.ServiceManager")
     88                         .getDeclaredMethod("getService", String.class).invoke(null, service);
     89             } catch (ClassCastException e) {
     90             } catch (ClassNotFoundException e) {
     91             } catch (NoSuchMethodException e) {
     92             } catch (InvocationTargetException e) {
     93             } catch (IllegalAccessException e) {
     94             }
     95 
     96             if (serviceBinder == null) {
     97                 Log.w(TAG, "Missing service " + service);
     98                 continue;
     99             }
    100 
    101             Log.d(TAG, "Dumping service " + service);
    102             final FileOutputStream out = new FileOutputStream(mTempFile);
    103             try {
    104                 serviceBinder.dump(out.getFD(), new String[0]);
    105             } catch (SecurityException e) {
    106                 String msg = e.getMessage();
    107                 if ((msg == null) || msg.contains("android.permission.DUMP")) {
    108                     // Service correctly checked for DUMP permission, yay
    109                 } else {
    110                     // Service is throwing about something else; they're
    111                     // probably not checking for DUMP.
    112                     throw e;
    113                 }
    114             } catch (TransactionTooLargeException | DeadObjectException e) {
    115                 // SELinux likely prevented the dump - assume safe
    116                 continue;
    117             } finally {
    118                 out.close();
    119             }
    120 
    121             // Verify that dump produced minimal output
    122             final BufferedReader reader = new BufferedReader(
    123                     new InputStreamReader(new FileInputStream(mTempFile)));
    124             final ArrayList<String> lines = new ArrayList<String>();
    125             try {
    126                 String line;
    127                 while ((line = reader.readLine()) != null) {
    128                     lines.add(line);
    129                     Log.v(TAG, "--> " + line);
    130                 }
    131             } finally {
    132                 reader.close();
    133             }
    134 
    135             if (lines.size() > 1) {
    136                 fail("dump() for " + service + " produced several lines of output; this "
    137                         + "may be leaking sensitive data.  At most, services should emit a "
    138                         + "single line when the caller doesn't have DUMP permission.");
    139             }
    140 
    141             if (lines.size() == 1) {
    142                 String message = lines.get(0);
    143                 if (!message.contains("Permission Denial") &&
    144                         !message.contains("android.permission.DUMP")) {
    145                     fail("dump() for " + service + " produced a single line which didn't "
    146                             + "reference a permission; it may be leaking sensitive data.");
    147                 }
    148             }
    149         }
    150     }
    151 }
    152