Monday, March 10, 2008

 

JAAS Callback Example

JAAS已經有內建讓你從console或是跳出一個GUI視窗讓使用者填入帳號密碼進行Authentication的功能了
如果你想要有其他種方式
就必須去實作CallbackHandler這個interface
下面我提供一個只有兩個類別、一個設定檔的範例給大家參考

SampleLoginModule.java


import java.util.Map;

import java.util.Arrays;

import javax.security.auth.Subject;
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.login.LoginException;
import javax.security.auth.spi.LoginModule;

public class SampleLoginModule implements LoginModule {

  private Subject subject;
  private CallbackHandler callbackHandler;
  private Map<String, ?> sharedState;
  private Map<String, ?> options;

  public void initialize(Subject subject, CallbackHandler callbackHandler,
      Map<String, ?> sharedState, Map<String, ?> options) {
    this.subject = subject;
    this.callbackHandler = callbackHandler;
    this.sharedState = sharedState;
    this.options = options;
  }

  public boolean login() throws LoginException {
    if (callbackHandler == null)
      throw new LoginException("Error: no CallbackHandler");

    Callback[] callbacks = new Callback[2];
    callbacks[0] = new NameCallback("user name: ");
    callbacks[1] = new PasswordCallback("password: ", true);

    try {
      callbackHandler.handle(callbacks);
    } catch (Exception e) {
      e.printStackTrace();
    }
    String username = ((NameCallback) callbacks[0]).getName();
    char[] password = ((PasswordCallback) callbacks[1]).getPassword();

    System.out.println("Username: " + username);
    System.out.println("Password: " + Arrays.toString(password));

    return true;
  }

  public boolean commit() throws LoginException {
    return true;
  }

  public boolean abort() throws LoginException {
    return true;
  }

  public boolean logout() throws LoginException {
    return true;
  }
}

Test.java


import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.login.LoginContext;

import com.sun.security.auth.callback.DialogCallbackHandler;
import com.sun.security.auth.callback.TextCallbackHandler;

public class Test {

  public static void main(String[] args) throws Exception {
    CallbackHandler textCallbackHandler = new TextCallbackHandler();
    CallbackHandler dialogCllbackHandler = new DialogCallbackHandler();

//    LoginContext lc = new LoginContext("Sample", textCallbackHandler);
    LoginContext lc = new LoginContext("Sample", dialogCllbackHandler);
    lc.login();
  }
}

sample_jaas.config


Sample {
    SampleLoginModule required;
};

放在同一個目錄中
執行


javac *.java
java -Djava.security.auth.login.config=sample_jaas.config Test
就可以跑跑看啦!

延伸閱讀

  1. jini寫的JAAS authentication 的介紹

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