libjava/classpath/gnu/javax/net/ssl/provider/SSLRandom.java

   1 /* SSLRandom.java -- SSLv3 pseudo-random function.
   2    Copyright (C) 2006  Free Software Foundation, Inc.
   3
   4 This file is a part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2 of the License, or (at
   9 your option) any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; if not, write to the Free Software
  18 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19 USA
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version.  */
  37
  38
  39 package gnu.javax.net.ssl.provider;
  40
  41 import java.util.Map;
  42 import gnu.java.security.hash.HashFactory;
  43 import gnu.java.security.hash.IMessageDigest;
  44 import gnu.java.security.prng.IRandom;
  45 import gnu.java.security.prng.LimitReachedException;
  46
  47 class SSLRandom implements IRandom
  48 {
  49
  50   // Fields.
  51   // -------------------------------------------------------------------------
  52
  53   static final String SECRET = "jessie.sslprng.secret";
  54   static final String SEED = "jessie.sslprng.seed";
  55
  56   private final IMessageDigest md5, sha;
  57   private byte[] secret;
  58   private byte[] buffer;
  59   private byte pad;
  60   private byte[] seed;
  61   private int idx;
  62
  63   // Constructor.
  64   // -------------------------------------------------------------------------
  65
  66   SSLRandom()
  67   {
  68     md5 = HashFactory.getInstance("MD5");
  69     sha = HashFactory.getInstance("SHA-1");
  70   }
  71
  72   // Instance methods.
  73   // -------------------------------------------------------------------------
  74
  75   public void init(Map attrib)
  76   {
  77     secret = (byte[]) attrib.get(SECRET);
  78     seed = (byte[]) attrib.get(SEED);
  79
  80     if (secret == null || seed == null)
  81       throw new NullPointerException();
  82
  83     pad = (byte) 'A';
  84     try { buffer = nextBlock(); }
  85     catch (LimitReachedException cantHappen) { }
  86   }
  87
  88   public String name()
  89   {
  90     return "SSLRandom";
  91   }
  92
  93   public Object clone()
  94   {
  95     throw new UnsupportedOperationException();
  96   }
  97
  98   public byte nextByte() throws LimitReachedException
  99   {
 100     if (buffer == null)
 101       throw new IllegalStateException();
 102     if (idx >= buffer.length)
 103       buffer = nextBlock();
 104     return buffer[idx++];
 105   }
 106
 107   public void nextBytes(byte[] buf, int off, int len)
 108     throws LimitReachedException
 109   {
 110     if (buffer == null)
 111       throw new IllegalStateException();
 112     if (buf == null)
 113       throw new NullPointerException();
 114     if (off < 0 || len < 0 || off+len > buf.length)
 115       throw new IndexOutOfBoundsException();
 116     int count = 0;
 117     while (count < len)
 118       {
 119         if (idx >= buffer.length)
 120           buffer = nextBlock();
 121         int l = Math.min(buffer.length-idx, len-count);
 122         System.arraycopy(buffer, idx, buf, off+count, l);
 123         count += l;
 124         idx += l;
 125       }
 126   }
 127
 128   public boolean selfTest()
 129   {
 130     return true; // XXX
 131   }
 132
 133   // For future versions of GNU Crypto. No-ops.
 134   public void addRandomByte (byte b)
 135   {
 136   }
 137
 138   public void addRandomBytes(byte[] buffer) {
 139     addRandomBytes(buffer, 0, buffer.length);
 140   }
 141
 142   public void addRandomBytes (byte[] b, int i, int j)
 143   {
 144   }
 145
 146   // Own methods.
 147   // -------------------------------------------------------------------------
 148
 149   private byte[] nextBlock() throws LimitReachedException
 150   {
 151     int count = pad - 'A' + 1;
 152     if (count > 26)
 153       throw new LimitReachedException();
 154     for (int i = 0; i < count; i++)
 155       sha.update(pad);
 156     sha.update(secret, 0, secret.length);
 157     sha.update(seed, 0, seed.length);
 158     byte[] b = sha.digest();
 159     md5.update(secret, 0, secret.length);
 160     md5.update(b, 0, b.length);
 161     idx = 0;
 162     pad++;
 163     return md5.digest();
 164   }
 165 }