1 /*
   2  * Copyright (c) 2017, 2019, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 import java.security.NoSuchAlgorithmException;
  25 
  26 import javax.net.ssl.SSLContext;
  27 import javax.net.ssl.SSLParameters;
  28 import javax.net.ssl.SSLSocketFactory;
  29 
  30 /*
  31  * This class is used for returning some specific JDK information.
  32  */
  33 public class JdkUtils {
  34 
  35     public static final String JAVA_RUNTIME_VERSION = "javaRuntimeVersion";
  36     public static final String SUPPORTED_PROTOCOLS = "supportedProtocols";
  37     public static final String SUPPORTED_CIPHER_SUITES = "supportedCipherSuites";
  38     public static final String SUPPORTS_SNI = "supportsSNI";
  39     public static final String SUPPORTS_ALPN = "supportsALPN";
  40 
  41     // Returns the JDK build version.
  42     public static String javaRuntimeVersion() {
  43         return System.getProperty("java.runtime.version");
  44     }
  45 
  46     private static String supportedProtocols() {
  47         StringBuilder protocols = new StringBuilder();
  48         for (String protocol : new String[] {
  49                 "TLSv1", "TLSv1.1", "TLSv1.2", "TLSv1.3" }) {
  50             if (supportsProtocol(protocol)) {
  51                 protocols.append(protocol).append(Utils.VALUE_DELIMITER);
  52             }
  53         }
  54         return protocols.toString().substring(
  55                 0, protocols.toString().length() - 1);
  56     }
  57 
  58     private static boolean supportsProtocol(String protocol) {
  59         boolean supported = true;
  60         try {
  61             SSLContext.getInstance(protocol);
  62         } catch (NoSuchAlgorithmException e) {
  63             supported = false;
  64         }
  65         return supported;
  66     }
  67 
  68     private static String supportedCipherSuites() {
  69         StringBuilder cipherSuites = new StringBuilder();
  70         String[] supportedCipherSuites = ((SSLSocketFactory) SSLSocketFactory
  71                 .getDefault()).getSupportedCipherSuites();
  72         for (int i = 0; i < supportedCipherSuites.length - 1; i++) {
  73             cipherSuites.append(supportedCipherSuites[i])
  74                     .append(Utils.VALUE_DELIMITER);
  75         }
  76         cipherSuites.append(
  77                 supportedCipherSuites[supportedCipherSuites.length - 1]);
  78         return cipherSuites.toString();
  79     }
  80 
  81     // Checks if SNI is supported by the JDK build.
  82     private static boolean supportsSNI() {
  83         boolean isSupported = true;
  84         try {
  85             SSLParameters.class.getMethod("getServerNames");
  86         } catch (NoSuchMethodException e) {
  87             isSupported = false;
  88         }
  89         return isSupported;
  90     }
  91 
  92     // Checks if ALPN is supported by the JDK build.
  93     private static boolean supportsALPN() {
  94         boolean isSupported = true;
  95         try {
  96             SSLParameters.class.getMethod("getApplicationProtocols");
  97         } catch (NoSuchMethodException e) {
  98             isSupported = false;
  99         }
 100         return isSupported;
 101     }
 102 
 103     public static void main(String[] args) throws NoSuchAlgorithmException {
 104         System.out.print(Utils.join(Utils.PARAM_DELIMITER,
 105                 attr(JAVA_RUNTIME_VERSION, javaRuntimeVersion()),
 106                 attr(SUPPORTED_PROTOCOLS, supportedProtocols()),
 107                 attr(SUPPORTED_CIPHER_SUITES, supportedCipherSuites()),
 108                 attr(SUPPORTS_SNI, supportsSNI()),
 109                 attr(SUPPORTS_ALPN, supportsALPN())));
 110     }
 111 
 112     private static String attr(String name, Object value) {
 113         return name + "=" + String.valueOf(value);
 114     }
 115 }