java - 如何使用 Java SASL API 和 CRAM-MD5

Question

我目前正在使用 Java SASL API，并编写了一个小程序来使用 CRAM-MD5 模拟质询响应序列。但是，我不确定如何执行此操作，因为 SaslClient 和 SaslServer 仅具有方法valuateChallenge(...) 和evaluateResponse(...)。我希望 SaslServer 有一个像 issuesChallenge(...) 或类似的方法，但它没有。那么正确的方法是什么？

在下面您可以找到我的(不起作用)代码。

    package mypackage;

    import java.io.IOException;

    import javax.security.auth.callback.Callback;
    import javax.security.auth.callback.CallbackHandler;
    import javax.security.auth.callback.NameCallback;
    import javax.security.auth.callback.PasswordCallback;
    import javax.security.auth.callback.UnsupportedCallbackException;
    import javax.security.sasl.AuthorizeCallback;
    import javax.security.sasl.Sasl;
    import javax.security.sasl.SaslClient;
    import javax.security.sasl.SaslException;
    import javax.security.sasl.SaslServer;

    public class Main {

    public static void main(String[] args) throws SaslException {

  new Main().start();
 }

 private static class ClientHandler implements CallbackHandler {

  @Override
  public void handle(Callback[] cbs) throws IOException, UnsupportedCallbackException {
   for (Callback cb : cbs) {
    if (cb instanceof NameCallback) {

     System.out.println("Client - NameCallback");

     NameCallback nc = (NameCallback)cb;
     nc.setName("username");
    } else if (cb instanceof PasswordCallback) {

     System.out.println("Client - PasswordCallback");

     PasswordCallback pc = (PasswordCallback)cb;
     pc.setPassword("password".toCharArray());
    }
   }
  }
 }

 private static class ServerHandler implements CallbackHandler {

  @Override
  public void handle(Callback[] cbs) throws IOException, UnsupportedCallbackException {
   for (Callback cb : cbs) {
    if (cb instanceof AuthorizeCallback) {

     System.out.println("Server - AuthorizeCallback");

     AuthorizeCallback ac = (AuthorizeCallback)cb;
     ac.setAuthorized(true);

    } else if (cb instanceof NameCallback) {

     System.out.println("Server - NameCallback");

     NameCallback nc = (NameCallback)cb;
     nc.setName("username");

    } else if (cb instanceof PasswordCallback) {

     System.out.println("Server - PasswordCallback");

     PasswordCallback pc = (PasswordCallback)cb;
     pc.setPassword("password".toCharArray());
    }
   }
  }
 }

 private void start() throws SaslException {

  byte[] challenge;
  byte[] response;

  ClientHandler clientHandler = new ClientHandler();
  ServerHandler serverHandler = new ServerHandler();

  SaslClient sc = Sasl.createSaslClient(new String[] { "CRAM-MD5" }, null, "my_server", "FQHN", null, clientHandler); 
  SaslServer ss = Sasl.createSaslServer("CRAM-MD5", "my_server", "FQHN", null, serverHandler);

  // Challenge response sequence (not working)
  challenge = ss.evaluateResponse(null);
  response = sc.evaluateChallenge(challenge);
  ss.evaluateResponse(response);

  if (ss.isComplete()) {
   System.out.println("Authentication successful.");
  }
 }
}

你好，弗雷德

Answer 1

我可以通过更改一行来使上述代码正常工作

来自

challenge = ss.evaluateResponse(null);

至

challenge = ss.evaluateResponse(new byte[0]);

evaluateResponse() 的 javadoc 说

this method is called to prepare an appropriate next challenge to submit to the client

所以我从上面猜测，不需要 issueChallange() 方法，evaluateResponse() 负责发出响应。