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