Download | Plain Text | No Line Numbers 

  1. /*
  2.  * Copyright (c) 2010, Manuel Mausz. All rights reserved.
  3.  *
  4.  * Redistribution and use in source and binary forms, with or without
  5.  * modification, are permitted provided that the following conditions
  6.  * are met:
  7.  *
  8.  *   - Redistributions of source code must retain the above copyright
  9.  *     notice, this list of conditions and the following disclaimer.
  10.  *
  11.  *   - Redistributions in binary form must reproduce the above copyright
  12.  *     notice, this list of conditions and the following disclaimer in the
  13.  *     documentation and/or other materials provided with the distribution.
  14.  *
  15.  *   - The names of the authors may not be used to endorse or promote products
  16.  *     derived from this software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  19.  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  20.  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  21.  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  22.  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  23.  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  24.  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  25.  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  26.  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  27.  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  28.  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29.  */
  30.  
  31. import java.io.*;
  32. import javax.crypto.*;
  33. import java.util.Collection;
  34. import java.util.Iterator;
  35. import org.bouncycastle.util.encoders.Base64;
  36. import java.security.GeneralSecurityException;
  37.  
  38. /*
  39.  * Common static methods used by all applications
  40.  *
  41.  * @author Manuel Mausz (0728348)
  42.  */
  43. class Utils
  44. {
  45.   static class Shutdown
  46.     extends java.lang.RuntimeException
  47.   {
  48.     public Shutdown()
  49.     {
  50.       super();
  51.     }
  52.  
  53.     public Shutdown(String message)
  54.     {
  55.       super(message);
  56.     }
  57.   }
  58.  
  59.   /*==========================================================================*/
  60.  
  61.   private static final String B64 = "a-zA-Z0-9/+";
  62.  
  63.   /*==========================================================================*/
  64.  
  65.   public static <T> String join(final Collection<T> objs, final String delimiter)
  66.   {
  67.     if (objs == null || objs.isEmpty())
  68.       return "";
  69.     Iterator<T> iter = objs.iterator();
  70.     StringBuffer buffer = new StringBuffer(iter.next().toString());
  71.     while (iter.hasNext())
  72.       buffer.append(delimiter).append(iter.next().toString());
  73.     return buffer.toString();
  74.   }
  75.  
  76.   /*--------------------------------------------------------------------------*/
  77.  
  78.   public static long parseHeaderNum(String[] args, int index)
  79.   {
  80.     long num = -1;
  81.     try
  82.     {
  83.       if (args.length < index + 1)
  84.         throw new NumberFormatException();
  85.       num = Long.parseLong(args[index]);
  86.       if (num < 0)
  87.         throw new NumberFormatException();
  88.     }
  89.     catch(NumberFormatException e)
  90.     {
  91.       System.err.println("Error: Invalid network paket from peer:");
  92.       System.err.println(join(java.util.Arrays.asList(args), " "));
  93.     }
  94.     return num;
  95.   }
  96.  
  97.   /*------------------------------------------------------------------------*/
  98.  
  99.   public static void sendOutput(EncObjectOutputStream out, String[] msgs)
  100.     throws IOException
  101.   {
  102.     out.writeLine("!output " + msgs.length);
  103.     for(String msg : msgs)
  104.       out.writeLine("!" + msg);
  105.     out.flush();
  106.   }
  107.  
  108.   /*------------------------------------------------------------------------*/
  109.  
  110.   public static void sendOutput(EncObjectOutputStream out, String msg)
  111.     throws IOException
  112.   {
  113.     String[] tmp = { msg };
  114.     sendOutput(out, tmp);
  115.   }
  116.  
  117.   /*------------------------------------------------------------------------*/
  118.  
  119.   public static void sendError(EncObjectOutputStream out, String[] msgs)
  120.     throws IOException
  121.   {
  122.     out.writeLine("!error " + msgs.length);
  123.     for(String msg : msgs)
  124.       out.writeLine("!" + msg);
  125.     out.flush();
  126.   }
  127.  
  128.   /*------------------------------------------------------------------------*/
  129.  
  130.   public static void sendError(EncObjectOutputStream out, String msg)
  131.     throws IOException
  132.   {
  133.     String[] tmp = { "Error: " + msg };
  134.     sendError(out, tmp);
  135.   }
  136.  
  137.   /*==========================================================================*/
  138.  
  139.   static class EncObjectInputStream
  140.     extends ObjectInputStream
  141.   {
  142.     private Cipher cipher = null;
  143.     private Mac mac = null;
  144.  
  145.     public EncObjectInputStream(InputStream in)
  146.       throws IOException
  147.     {
  148.       super(in);
  149.     }
  150.  
  151.     /*------------------------------------------------------------------------*/
  152.  
  153.     public void setCipher(Cipher cipher)
  154.     {
  155.       this.cipher = cipher;
  156.     }
  157.  
  158.     /*------------------------------------------------------------------------*/
  159.  
  160.     public void setMAC(Mac mac)
  161.     {
  162.       this.mac = mac;
  163.     }
  164.  
  165.     /*------------------------------------------------------------------------*/
  166.  
  167.     private String decode(String msg)
  168.     {
  169.       if (msg == null)
  170.         return null;
  171.       if ((cipher == null && mac == null) || msg.charAt(0) == '!')
  172.         return msg;
  173.  
  174.       if (mac != null)
  175.       {
  176.         msg = new String(Base64.decode(msg));
  177.         assert msg.matches("[" + B64 + "]{43}= [\\s[^\\s]]+");
  178.         int ix = msg.indexOf(' ');
  179.         if (ix == -1)
  180.         {
  181.           System.err.println("Error: invalid hashed message format:");
  182.           System.err.println(msg);
  183.           return null;
  184.         }
  185.         String hasht = msg.substring(0, ix);
  186.         String msgtmp = msg.substring(ix + 1);
  187.         String hashc = new String(Base64.encode(mac.doFinal(msgtmp.getBytes())));
  188.         if (!hasht.equals(hashc))
  189.         {
  190.           System.err.println("Error: invalid MAC:");
  191.           System.err.println(msg);
  192.           throw new HashError();
  193.           //return null;
  194.         }
  195.         msg = msgtmp;
  196.       }
  197.  
  198.       if (cipher != null)
  199.       {
  200.         try
  201.         {
  202.           byte[] decmsg = Base64.decode(msg);
  203.           return new String(cipher.doFinal(decmsg));
  204.         }
  205.         catch(GeneralSecurityException e)
  206.         {
  207.           System.err.println("Error: Unable to decode message: " + e.getMessage());
  208.           return null;
  209.         }
  210.       }
  211.  
  212.       return msg;
  213.     }
  214.  
  215.     /*------------------------------------------------------------------------*/
  216.  
  217.     public String readUTF()
  218.       throws IOException
  219.     {
  220.       return decode(super.readUTF());
  221.     }
  222.  
  223.     /*------------------------------------------------------------------------*/
  224.  
  225.     @SuppressWarnings("deprecation")
  226.     public String readLine()
  227.       throws IOException
  228.     {
  229.       return decode(super.readLine());
  230.     }
  231.   }
  232.  
  233.   /*==========================================================================*/
  234.  
  235.   static class EncObjectOutputStream
  236.     extends ObjectOutputStream
  237.   {
  238.     private Cipher cipher = null;
  239.     private Mac mac = null;
  240.  
  241.     public EncObjectOutputStream(OutputStream out)
  242.       throws IOException
  243.     {
  244.       super(out);
  245.     }
  246.  
  247.     /*------------------------------------------------------------------------*/
  248.  
  249.     public void setCipher(Cipher cipher)
  250.     {
  251.       this.cipher = cipher;
  252.     }
  253.  
  254.     /*------------------------------------------------------------------------*/
  255.  
  256.     public void setMAC(Mac mac)
  257.     {
  258.       this.mac = mac;
  259.     }
  260.  
  261.     /*------------------------------------------------------------------------*/
  262.  
  263.     private byte[] encode(byte[] msg)
  264.     {
  265.       try
  266.       {
  267.         return Base64.encode(cipher.doFinal(msg));
  268.       }
  269.       catch(GeneralSecurityException e)
  270.       {
  271.         System.err.println("Error: Unable to encode message: " + e.getMessage());
  272.       }
  273.       return null;
  274.     }
  275.  
  276.     /*------------------------------------------------------------------------*/
  277.  
  278.     public void writeUTF(String msg)
  279.       throws IOException
  280.     {
  281.       if (cipher == null && mac == null)
  282.       {
  283.         super.writeUTF(msg);
  284.         return;
  285.       }
  286.  
  287.       if (mac != null)
  288.       {
  289.         byte[] hash = mac.doFinal(msg.getBytes());
  290.         msg = new String(Base64.encode(hash)) + " " + msg;
  291.         assert msg.matches("[" + B64 + "]{43}= [\\s[^\\s]]+");
  292.       }
  293.  
  294.       if (cipher != null)
  295.       {
  296.         super.writeUTF(new String(encode(msg.getBytes())));
  297.         return;
  298.       }
  299.  
  300.       String hashedmsg = new String(Base64.encode(msg.getBytes()));
  301.       super.writeUTF(hashedmsg);
  302.       return;
  303.     }
  304.  
  305.     /*------------------------------------------------------------------------*/
  306.  
  307.     public void writeLine(String msg)
  308.       throws IOException
  309.     {
  310.       if (cipher == null && mac == null)
  311.       {
  312.         super.writeBytes(msg + "\n");
  313.         return;
  314.       }
  315.  
  316.       if (mac != null)
  317.       {
  318.         byte[] hash = mac.doFinal(msg.getBytes());
  319.         msg = new String(Base64.encode(hash)) + " " + msg;
  320.         assert msg.matches("[" + B64 + "]{43}= [\\s[^\\s]]+");
  321.       }
  322.  
  323.       if (cipher != null)
  324.       {
  325.         super.writeBytes(new String(encode(msg.getBytes())) + "\n");
  326.         return;
  327.       }
  328.  
  329.       super.writeBytes(new String(Base64.encode(msg.getBytes())) + "\n");
  330.       return;
  331.     }
  332.   }
  333.  
  334.   /*==========================================================================*/
  335.  
  336.   static class HashError
  337.     extends java.lang.RuntimeException
  338.   {
  339.     public HashError()
  340.     {
  341.       super();
  342.     }
  343.   }
  344. }
  345.