use Java methods for setting permissions on native executables

As of android-9, java.io.File has native methods for setting permissions,
inherited from Java 1.6.  Using these will help deal with compatibility
across devices, since some devices might not have chmod installed.

src/org/torproject/android/service/TorResourceInstaller.java

@@ -8,12 +8,10 @@ import java.io.DataOutputStream;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
-import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.PrintStream;
-import java.io.PrintWriter;
 import java.io.StringBufferInputStream;
 import java.util.ArrayList;
 import java.util.concurrent.TimeoutException;
@@ -96,11 +94,13 @@ public class TorResourceInstaller implements TorServiceConstants {
 	        outFile = new File(installFolder, OBFSCLIENT_ASSET_KEY);
 	        shell.add(new SimpleCommand(COMMAND_RM_FORCE + outFile.getAbsolutePath())).waitForFinish();
 	        streamToFile(is,outFile, false, true);
+	        setExecutable(outFile);
 	        
 	        is = context.getResources().openRawResource(R.raw.meek);
 	        outFile = new File(installFolder, MEEK_ASSET_KEY);
 	        shell.add(new SimpleCommand(COMMAND_RM_FORCE + outFile.getAbsolutePath())).waitForFinish();
 	        streamToFile(is,outFile, false, true);
+	        setExecutable(outFile);
 	        
 	        cpuPath = "armeabi";
         }
@@ -111,17 +111,19 @@ public class TorResourceInstaller implements TorServiceConstants {
         outFile = new File(installFolder, TOR_ASSET_KEY);
         shell.add(new SimpleCommand(COMMAND_RM_FORCE + outFile.getAbsolutePath())).waitForFinish();
         streamToFile(is,outFile, false, true);
+        setExecutable(outFile);
     
         is = context.getAssets().open(cpuPath + "/polipo.mp3");
         outFile = new File(installFolder, POLIPO_ASSET_KEY);
         shell.add(new SimpleCommand(COMMAND_RM_FORCE + outFile.getAbsolutePath())).waitForFinish();
         streamToFile(is,outFile, false, true);
+        setExecutable(outFile);
     
         is = context.getAssets().open(cpuPath + "/xtables.mp3");
         outFile = new File(installFolder, IPTABLES_ASSET_KEY);
         shell.add(new SimpleCommand(COMMAND_RM_FORCE + outFile.getAbsolutePath())).waitForFinish();
         streamToFile(is,outFile, false, true);
-   
+        setExecutable(outFile);
     
         return true;
     }
@@ -359,4 +361,11 @@ public class TorResourceInstaller implements TorServiceConstants {
     }*/
     
 
+    private void setExecutable(File fileBin) {
+        fileBin.setReadable(true);
+        fileBin.setExecutable(true);
+        fileBin.setWritable(false);
+        fileBin.setWritable(true, true);
+    }
+
 }

src/org/torproject/android/service/TorService.java

@@ -649,15 +649,10 @@ public class TorService extends Service implements TorServiceConstants, OrbotCon
             appCacheHome = getDir(DIRECTORY_TOR_DATA,Application.MODE_PRIVATE);
         
         fileTor= new File(appBinHome, TOR_ASSET_KEY);
-        
         filePolipo = new File(appBinHome, POLIPO_ASSET_KEY);
-        
         fileObfsclient = new File(appBinHome, OBFSCLIENT_ASSET_KEY);
-        
         fileMeekclient = new File(appBinHome, MEEK_ASSET_KEY);
-        
         fileTorRc = new File(appBinHome, TORRC_ASSET_KEY);
-        
         fileXtables = new File(appBinHome, IPTABLES_ASSET_KEY);
 
         SharedPreferences prefs = TorServiceUtils.getSharedPrefs(getApplicationContext());
@@ -678,8 +673,6 @@ public class TorService extends Service implements TorServiceConstants, OrbotCon
         }
 
         updateTorConfigFile ();
-        
-
     }
 
     private boolean updateTorConfigFile () throws FileNotFoundException, IOException, TimeoutException
@@ -738,27 +731,6 @@ public class TorService extends Service implements TorServiceConstants, OrbotCon
         return success;
     }
 
-    private boolean enableBinExec (File fileBin) throws Exception
-    {
-        
-        logNotice(fileBin.getName() + ": PRE: Is binary exec? " + fileBin.canExecute());
-  
-        if (!fileBin.canExecute())
-        {
-            logNotice("(re)Setting permission on binary: " + fileBin.getCanonicalPath());    
-            
-            Shell shell = Shell.startShell();
-            shell.add(new SimpleCommand("chmod " + CHMOD_EXE_VALUE + ' ' + fileBin.getCanonicalPath())).waitForFinish();
-            
-            File fileTest = new File(fileBin.getCanonicalPath());
-            logNotice(fileTest.getName() + ": POST: Is binary exec? " + fileTest.canExecute());
-            
-            shell.close();
-        }
-        
-        return fileBin.canExecute();
-    }
-    
     private void startTor () throws Exception
     {
         
@@ -768,12 +740,6 @@ public class TorService extends Service implements TorServiceConstants, OrbotCon
         if (fileTor == null)
             initBinariesAndDirectories();
 
-        enableBinExec(fileTor);
-        enableBinExec(filePolipo);    
-        enableBinExec(fileObfsclient);
-        enableBinExec(fileMeekclient);
-        enableBinExec(fileXtables);
-
         logNotice(getString(R.string.status_starting_up));
         sendCallbackLogMessage(getString(R.string.status_starting_up));
         
@@ -1361,8 +1327,6 @@ public class TorService extends Service implements TorServiceConstants, OrbotCon
 
                 mCurrentStatus = STATUS_OFF;  
                 sendCallbackStatus(mCurrentStatus);
-            
-                
             }
         }