1 /*

     2  * Copyright (c) 2015, 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.io.IOException;

    29 import java.nio.charset.*;

    30 import java.util.*;

    31 

    32 import javax.net.ssl.*;

    33 

    34 /*

    35  * [RFC 7301]

    36  * This TLS extension facilitates the negotiation of application-layer protocols

    37  * within the TLS handshake. Clients MAY include an extension of type

    38  * "application_layer_protocol_negotiation" in the (extended) ClientHello

    39  * message. The "extension_data" field of this extension SHALL contain a

    40  * "ProtocolNameList" value:

    41  *

    42  *     enum {

    43  *         application_layer_protocol_negotiation(16), (65535)

    44  *     } ExtensionType;

    45  *

    46  *     opaque ProtocolName<1..2^8-1>;

    47  *

    48  *     struct {

    49  *         ProtocolName protocol_name_list<2..2^16-1>

    50  *     } ProtocolNameList;

    51  */

    52 final class ALPNExtension extends HelloExtension {

    53 

    54     final static int ALPN_HEADER_LENGTH = 1;

    55     final static int MAX_APPLICATION_PROTOCOL_LENGTH = 255;

    56     final static int MAX_APPLICATION_PROTOCOL_LIST_LENGTH = 65535;

    57     private int listLength = 0;     // ProtocolNameList length

    58     private List<String> protocolNames = null;

    59 

    60     // constructor for ServerHello

    61     ALPNExtension(String protocolName) throws SSLException {

    62         this(new String[]{ protocolName });

    63     }

    64 

    65     // constructor for ClientHello

    66     ALPNExtension(String[] protocolNames) throws SSLException {

    67         super(ExtensionType.EXT_ALPN);

    68         if (protocolNames.length == 0) { // never null, never empty

    69             throw new IllegalArgumentException(

    70                 "The list of application protocols cannot be empty");

    71         }

    72         this.protocolNames = Arrays.asList(protocolNames);

    73         for (String p : protocolNames) {

    74             int length = p.getBytes(StandardCharsets.UTF_8).length;

    75             if (length == 0) {

    76                 throw new SSLProtocolException(

    77                     "Application protocol name is empty");

    78             }

    79             if (length <= MAX_APPLICATION_PROTOCOL_LENGTH) {

    80                 listLength += length + ALPN_HEADER_LENGTH;

    81             } else {

    82                 throw new SSLProtocolException(

    83                     "Application protocol name is too long: " + p);

    84             }

    85             if (listLength > MAX_APPLICATION_PROTOCOL_LIST_LENGTH) {

    86                 throw new SSLProtocolException(

    87                     "Application protocol name list is too long");

    88             }

    89         }

    90     }

    91 

    92     // constructor for ServerHello for parsing ALPN extension

    93     ALPNExtension(HandshakeInStream s, int len) throws IOException {

    94         super(ExtensionType.EXT_ALPN);

    95 

    96         if (len >= 2) {

    97             listLength = s.getInt16(); // list length

    98             if (listLength < 2 || listLength + 2 != len) {

    99                 throw new SSLProtocolException(

   100                     "Invalid " + type + " extension: incorrect list length " +

   101                     "(length=" + listLength + ")");

   102             }

   103         } else {

   104             throw new SSLProtocolException(

   105                 "Invalid " + type + " extension: insufficient data " +

   106                 "(length=" + len + ")");

   107         }

   108 

   109         int remaining = listLength;

   110         this.protocolNames = new ArrayList<>();

   111         while (remaining > 0) {

   112             // opaque ProtocolName<1..2^8-1>; // RFC 7301

   113             byte[] bytes = s.getBytes8();

   114             if (bytes.length == 0) {

   115                 throw new SSLProtocolException("Invalid " + type +

   116                     " extension: empty application protocol name");

   117             }

   118             String p =

   119                 new String(bytes, StandardCharsets.UTF_8); // app protocol

   120             protocolNames.add(p);

   121             remaining -= bytes.length + ALPN_HEADER_LENGTH;

   122         }

   123 

   124         if (remaining != 0) {

   125             throw new SSLProtocolException(

   126                 "Invalid " + type + " extension: extra data " +

   127                 "(length=" + remaining + ")");

   128         }

   129     }

   130 

   131     List<String> getPeerAPs() {

   132         return protocolNames;

   133     }

   134 

   135     /*

   136      * Return the length in bytes, including extension type and length fields.

   137      */

   138     @Override

   139     int length() {

   140         return 6 + listLength;

   141     }

   142 

   143     @Override

   144     void send(HandshakeOutStream s) throws IOException {

   145         s.putInt16(type.id);

   146         s.putInt16(listLength + 2); // length of extension_data

   147         s.putInt16(listLength);     // length of ProtocolNameList

   148 

   149         for (String p : protocolNames) {

   150             s.putBytes8(p.getBytes(StandardCharsets.UTF_8));

   151         }

   152     }

   153 

   154     @Override

   155     public String toString() {

   156         StringBuilder sb = new StringBuilder();

   157         if (protocolNames == null || protocolNames.isEmpty()) {

   158             sb.append("<empty>");

   159         } else {

   160             for (String protocolName : protocolNames) {

   161                 sb.append("[" + protocolName + "]");

   162             }

   163         }

   164 

   165         return "Extension " + type +

   166             ", protocol names: " + sb;

   167     }

   168 }