1 /*
   2  * Copyright (c) 1996, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.security.ssl;
  27 
  28 import java.security.SecureRandom;
  29 import java.util.Arrays;
  30 import javax.net.ssl.SSLProtocolException;
  31 
  32 /**
  33  * Encapsulates an SSL session ID.
  34  *
  35  * @author Satish Dharmaraj
  36  * @author David Brownell
  37  */
  38 final class SessionId {
  39     private static final int MAX_LENGTH = 32;
  40     private final byte[] sessionId;          // max 32 bytes
  41 
  42     // Constructs a new session ID ... perhaps for a rejoinable session
  43     SessionId(boolean isRejoinable, SecureRandom generator) {
  44         if (isRejoinable && (generator != null)) {
  45             sessionId = new RandomCookie(generator).randomBytes;
  46         } else {
  47             sessionId = new byte[0];
  48         }
  49     }
  50 
  51     // Constructs a session ID from a byte array (max size 32 bytes)
  52     SessionId(byte[] sessionId) {
  53         this.sessionId = sessionId.clone();
  54     }
  55 
  56     // Returns the length of the ID, in bytes
  57     int length() {
  58         return sessionId.length;
  59     }
  60 
  61     // Returns the bytes in the ID.  May be an empty array.
  62     byte[] getId() {
  63         return sessionId.clone();
  64     }
  65 
  66     // Returns the ID as a string
  67     @Override
  68     public String toString() {
  69         if (sessionId.length == 0) {
  70             return "";
  71         }
  72 
  73         return Utilities.toHexString(sessionId);
  74     }
  75 
  76 
  77     // Returns a value which is the same for session IDs which are equal
  78     @Override
  79     public int hashCode() {
  80         return Arrays.hashCode(sessionId);
  81     }
  82 
  83     // Returns true if the parameter is the same session ID
  84     @Override
  85     public boolean equals (Object obj) {
  86         if (obj == this) {
  87             return true;
  88         }
  89 
  90         if (obj instanceof SessionId) {
  91             SessionId that = (SessionId)obj;
  92             return Arrays.equals(this.sessionId, that.sessionId);
  93         }
  94 
  95         return false;
  96     }
  97 
  98     /**
  99      * Checks the length of the session ID to make sure it sits within
 100      * the range called out in the specification
 101      */
 102     void checkLength(int protocolVersion) throws SSLProtocolException {
 103         // As of today all versions of TLS have a 32-byte maximum length.
 104         // In the future we can do more here to support protocol versions
 105         // that may have longer max lengths.
 106         if (sessionId.length > MAX_LENGTH) {
 107             throw new SSLProtocolException("Invalid session ID length (" +
 108                     sessionId.length + " bytes)");
 109         }
 110     }
 111 }