UNCKerberos.java

package net.sourceforge.solexatools.authentication;

import java.io.IOException;
import java.util.HashMap;

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.callback.UnsupportedCallbackException;
import javax.security.auth.login.LoginException;

import com.sun.security.auth.module.Krb5LoginModule;

/**
 * <p>
 * UNCKerberos class.
 * </p>
 * 
 * @author boconnor
 * @version $Id: $Id
 */
public class UNCKerberos extends Authentication {

    /**
     * {@inheritDoc}
     * 
     * Get boolean true/false based on onyen/password pair. No exception is thrown.
     * 
     * @return
     */
    @Override
    public boolean loginSuccess(String uid, String password) {
        String user = uid;
        if (uid.contains("@")) {
            String[] t = uid.split("\\@");
            user = t[0];
        }
        try {
            return (getSubject(user, password, null) != null);
        } catch (Exception e) {
            e.printStackTrace();
            System.err.println(e.getMessage());
        }
        return (false);
    }

    // does the heavy-lifting for methods, above
    /**
     * <p>
     * getSubject.
     * </p>
     * 
     * @param uid
     *            a {@link java.lang.String} object.
     * @param password
     *            a {@link java.lang.String} object.
     * @param keytabfile
     *            a {@link java.lang.String} object.
     * @return a {@link javax.security.auth.Subject} object.
     * @throws javax.security.auth.login.LoginException
     *             if any.
     */
    protected Subject getSubject(String uid, String password, String keytabfile) throws LoginException {
        try {
            Subject jSubject = null;

            if (password != null) {

                Krb5LoginModule lm = new com.sun.security.auth.module.Krb5LoginModule();

                HashMap options = new HashMap();
                jSubject = new Subject();
                options.put("doNotPrompt", "false");
                // options.put("debug", "true");

                lm.initialize(jSubject, new NamePasswordCallbackHandler(uid, password), null, options);
                lm.logout();
                lm.login();
                lm.commit();
            } else {
                // use the old way for keytabs
                Krb5LoginModule lm = new com.sun.security.auth.module.Krb5LoginModule();
                HashMap options = new HashMap();
                jSubject = new Subject();
                options.put("principal", uid);
                options.put("keyTab", keytabfile);
                options.put("useTicketCache", "false");
                options.put("useKeyTab", "true");
                options.put("storeKey", "true");
                options.put("doNotPrompt", "true");
                // options.put("debug", "true");
                lm.initialize(jSubject, null, null, options);
                lm.logout();
                lm.login();
                lm.commit();
            }

            return jSubject;
        } catch (LoginException e) {
            throw e;
        }
    }

    /**
     * <p>
     * isConfigError.
     * </p>
     * 
     * @param e
     *            a {@link java.lang.Throwable} object.
     * @return a boolean.
     */
    protected boolean isConfigError(Throwable e) {
        boolean rval = false;
        Throwable t = e.getCause();
        if (t != null) {
            rval = isConfigError(t);
        }

        if (!rval) {
            StackTraceElement[] ste = e.getStackTrace();
            for (StackTraceElement e1 : ste) {
                String s = e1.getClassName();
                if ("sun.security.krb5.Config".equals(s)) {
                    rval = true;
                    break;
                }
            }
        }
        return rval;
    }

    protected class NamePasswordCallbackHandler implements CallbackHandler {

        String username;
        String password;

        public NamePasswordCallbackHandler(String onyen, String pwd) {
            super();
            username = onyen;
            password = pwd;
        }

        @Override
        public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException {
            boolean n = false;
            boolean p = false;
            for (Callback c : callbacks) {
                if (c instanceof NameCallback) {
                    NameCallback nc = (NameCallback) c;
                    nc.setName(username);
                    n = true;
                } else if (c instanceof PasswordCallback) {
                    PasswordCallback pc = (PasswordCallback) c;

                    // pc.setPassword( password.toCharArray() );
                    byte[] bytes = password.getBytes();

                    int length = password.length();
                    char[] passwordChars = new char[length];

                    for (int j = 0; j < length; j++) {
                        passwordChars[j] = (char) bytes[j];// password.charAt(j);
                    }

                    pc.setPassword(passwordChars);

                    p = true;
                }
                if (n && p) {
                    break;
                }
            }
        }
    }
}