/*
 * @(#)JndiLoginModule.java	1.11 04/05/05
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.security.auth.module;

import javax.security.auth.*;
import javax.security.auth.callback.*;
import javax.security.auth.login.*;
import javax.security.auth.spi.*;
import javax.naming.*;
import javax.naming.directory.*;

import java.io.IOException;
import java.util.Map;
import java.util.LinkedList;
import java.util.ResourceBundle;

import com.sun.security.auth.UnixPrincipal;
import com.sun.security.auth.UnixNumericUserPrincipal;
import com.sun.security.auth.UnixNumericGroupPrincipal;

import sun.security.util.AuthResources; 

/**
 * <p> The module prompts for a username and password
 * and then verifies the password against the password stored in
 * a directory service configured under JNDI.
 *
 * <p> This <code>LoginModule</code> interoperates with
 * any conformant JNDI service provider.  To direct this
 * <code>LoginModule</code> to use a specific JNDI service provider,
 * two options must be specified in the login <code>Configuration</code>
 * for this <code>LoginModule</code>.
 * <pre>
 *	user.provider.url=<b>name_service_url</b>
 *	group.provider.url=<b>name_service_url</b>
 * </pre>
 *
 * <b>name_service_url</b> specifies
 * the directory service and path where this <code>LoginModule</code>
 * can access the relevant user and group information.  Because this
 * <code>LoginModule</code> only performs one-level searches to
 * find the relevant user information, the <code>URL</code>
 * must point to a directory one level above where the user and group
 * information is stored in the directory service.
 * For example, to instruct this <code>LoginModule</code>
 * to contact a NIS server, the following URLs must be specified:
 * <pre>
 *    user.provider.url="nis://<b>NISServerHostName</b>/<b>NISDomain</b>/user"
 *    group.provider.url="nis://<b>NISServerHostName</b>/<b>NISDomain</b>/system/group"
 * </pre>
 *
 * <b>NISServerHostName</b> specifies the server host name of the
 * NIS server (for example, <i>nis.sun.com</i>, and <b>NISDomain</b>
 * specifies the domain for that NIS server (for example, <i>jaas.sun.com</i>.
 * To contact an LDAP server, the following URLs must be specified:
 * <pre>
 *    user.provider.url="ldap://<b>LDAPServerHostName</b>/<b>LDAPName</b>"
 *    group.provider.url="ldap://<b>LDAPServerHostName</b>/<b>LDAPName</b>"
 * </pre>
 *
 * <b>LDAPServerHostName</b> specifies the server host name of the
 * LDAP server, which may include a port number
 * (for example, <i>ldap.sun.com:389</i>),
 * and <b>LDAPName</b> specifies the entry name in the LDAP directory
 * (for example, <i>ou=People,o=Sun,c=US</i> and <i>ou=Groups,o=Sun,c=US</i>
 * for user and group information, respectively).
 *
 * <p> The format in which the user's information must be stored in
 * the directory service is specified in RFC 2307.  Specifically,
 * this <code>LoginModule</code> will search for the user's entry in the
 * directory service using the user's <i>uid</i> attribute,
 * where <i>uid=<b>username</b></i>.  If the search succeeds,
 * this <code>LoginModule</code> will then
 * obtain the user's encrypted password from the retrieved entry
 * using the <i>userPassword</i> attribute.
 * This <code>LoginModule</code> assumes that the password is stored
 * as a byte array, which when converted to a <code>String</code>,
 * has the following format:
 * <pre>
 *	"{crypt}<b>encrypted_password</b>"
 * </pre>
 * 
 * The LDAP directory server must be configured
 * to permit read access to the userPassword attribute.
 * If the user entered a valid username and password,
 * this <code>LoginModule</code> associates a
 * <code>UnixPrincipal</code>, <code>UnixNumericUserPrincipal</code>,
 * and the relevant UnixNumericGroupPrincipals with the
 * <code>Subject</code>.
 * 
 * <p> This LoginModule also recognizes the following <code>Configuration</code>
 * options:
 * <pre>
 *    debug          if, true, debug messages are output to System.out.
 *
 *    useFirstPass   if, true, this LoginModule retrieves the
 *                   username and password from the module's shared state,
 *                   using "javax.security.auth.login.name" and
 *                   "javax.security.auth.login.password" as the respective
 *                   keys.  The retrieved values are used for authentication.
 *                   If authentication fails, no attempt for a retry is made,
 *                   and the failure is reported back to the calling
 *                   application.
 *
 *    tryFirstPass   if, true, this LoginModule retrieves the
 *                   the username and password from the module's shared state,
 *                   using "javax.security.auth.login.name" and
 *                   "javax.security.auth.login.password" as the respective
 *                   keys.  The retrieved values are used for authentication.
 *                   If authentication fails, the module uses the
 *                   CallbackHandler to retrieve a new username and password,
 *                   and another attempt to authenticate is made.
 *                   If the authentication fails, the failure is reported
 *                   back to the calling application.
 *
 *    storePass      if, true, this LoginModule stores the username and password
 *                   obtained from the CallbackHandler in the module's
 *                   shared state, using "javax.security.auth.login.name" and
 *                   "javax.security.auth.login.password" as the respective
 *                   keys.  This is not performed if existing values already
 *                   exist for the username and password in the shared state,
 *                   or if authentication fails.
 *
 *    clearPass     if, true, this <code>LoginModule</code> clears the
 *                  username and password stored in the module's shared state
 *                  after both phases of authentication (login and commit)
 *                  have completed.
 * </pre>
 *
 * @version 1.11, 05/05/04
 */
public class JndiLoginModule implements LoginModule {

    static final java.util.ResourceBundle rb =
        java.util.ResourceBundle.getBundle("sun.security.util.AuthResources");

    /** JNDI Provider */
    public final String USER_PROVIDER = "user.provider.url";
    public final String GROUP_PROVIDER = "group.provider.url";

    // configurable options
    private boolean debug = false;
    private boolean strongDebug = false;
    private String userProvider;
    private String groupProvider;
    private boolean useFirstPass = false;
    private boolean tryFirstPass = false;
    private boolean storePass = false;
    private boolean clearPass = false;

    // the authentication status
    private boolean succeeded = false;
    private boolean commitSucceeded = false;

    // username, password, and JNDI context
    private String username;
    private char[] password;
    DirContext ctx;

    // the user (assume it is a UnixPrincipal)
    private UnixPrincipal userPrincipal;
    private UnixNumericUserPrincipal UIDPrincipal;
    private UnixNumericGroupPrincipal GIDPrincipal;
    private LinkedList supplementaryGroups = new LinkedList();

    // initial state
    private Subject subject;
    private CallbackHandler callbackHandler;
    private Map sharedState;
    private Map options;

    private static final String CRYPT = "{crypt}";
    private static final String USER_PWD = "userPassword";
    private static final String USER_UID = "uidNumber";
    private static final String USER_GID = "gidNumber";
    private static final String GROUP_ID = "gidNumber";
    private static final String NAME = "javax.security.auth.login.name";
    private static final String PWD = "javax.security.auth.login.password";

    /**
     * Initialize this <code>LoginModule</code>.
     *
     * <p>
     *
     * @param subject the <code>Subject</code> to be authenticated. <p>
     *
     * @param callbackHandler a <code>CallbackHandler</code> for communicating
     *			with the end user (prompting for usernames and
     *			passwords, for example). <p>
     *
     * @param sharedState shared <code>LoginModule</code> state. <p>
     *
     * @param options options specified in the login
     *			<code>Configuration</code> for this particular
     *			<code>LoginModule</code>.
     */
    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;

	// initialize any configured options
	debug = "true".equalsIgnoreCase((String)options.get("debug"));
	strongDebug =
		"true".equalsIgnoreCase((String)options.get("strongDebug"));
	userProvider = (String)options.get(USER_PROVIDER);
	groupProvider = (String)options.get(GROUP_PROVIDER);
	tryFirstPass =
		"true".equalsIgnoreCase((String)options.get("tryFirstPass"));
	useFirstPass =
		"true".equalsIgnoreCase((String)options.get("useFirstPass"));
	storePass =
		"true".equalsIgnoreCase((String)options.get("storePass"));
	clearPass =
		"true".equalsIgnoreCase((String)options.get("clearPass"));
    }

    /**
     * <p> Prompt for username and password.
     * Verify the password against the relevant name service.
     *
     * <p>
     *
     * @return true always, since this <code>LoginModule</code>
     *		should not be ignored.
     *
     * @exception FailedLoginException if the authentication fails. <p>
     *
     * @exception LoginException if this <code>LoginModule</code>
     *		is unable to perform the authentication.
     */
    public boolean login() throws LoginException {

	if (userProvider == null) {
	    throw new LoginException
		("Error: Unable to locate JNDI user provider");
	}
	if (groupProvider == null) {
	    throw new LoginException
		("Error: Unable to locate JNDI group provider");
	}

	if (debug) {
	    System.out.println("\t\t[JndiLoginModule] user provider: " +
				userProvider);
	    System.out.println("\t\t[JndiLoginModule] group provider: " +
				groupProvider);
	}

	// attempt the authentication
	if (tryFirstPass) {

	    try {
		// attempt the authentication by getting the
		// username and password from shared state
		attemptAuthentication(true);

		// authentication succeeded
		succeeded = true;
		if (debug) {
		    System.out.println("\t\t[JndiLoginModule] " +
				"tryFirstPass succeeded");
		}
		return true;
	    } catch (LoginException le) {
		// authentication failed -- try again below by prompting
		cleanState();
		if (debug) {
		    System.out.println("\t\t[JndiLoginModule] " +
				"tryFirstPass failed with:" +
				le.toString());
		}
	    }

	} else if (useFirstPass) {

	    try {
		// attempt the authentication by getting the
		// username and password from shared state
		attemptAuthentication(true);

		// authentication succeeded
		succeeded = true;
		if (debug) {
		    System.out.println("\t\t[JndiLoginModule] " +
				"useFirstPass succeeded");
		}
		return true;
	    } catch (LoginException le) {
		// authentication failed
		cleanState();
		if (debug) {
		    System.out.println("\t\t[JndiLoginModule] " +
				"useFirstPass failed");
		}
		throw le;
	    }
	}

	// attempt the authentication by prompting for the username and pwd
	try {
	    attemptAuthentication(false);

	    // authentication succeeded
	   succeeded = true;
	    if (debug) {
		System.out.println("\t\t[JndiLoginModule] " +
				"regular authentication succeeded");
	    }
	    return true;
	} catch (LoginException le) {
	    cleanState();
	    if (debug) {
		System.out.println("\t\t[JndiLoginModule] " +
				"regular authentication failed");
	    }
	    throw le;
	}
    }

    /**
     * Abstract method to commit the authentication process (phase 2).
     *
     * <p> This method is called if the LoginContext's
     * overall authentication succeeded
     * (the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules
     * succeeded).
     *
     * <p> If this LoginModule's own authentication attempt
     * succeeded (checked by retrieving the private state saved by the
     * <code>login</code> method), then this method associates a
     * <code>UnixPrincipal</code>
     * with the <code>Subject</code> located in the
     * <code>LoginModule</code>.  If this LoginModule's own
     * authentication attempted failed, then this method removes
     * any state that was originally saved.
     *
     * <p>
     *
     * @exception LoginException if the commit fails
     *
     * @return true if this LoginModule's own login and commit
     *		attempts succeeded, or false otherwise.
     */
    public boolean commit() throws LoginException {

	if (succeeded == false) {
	    return false;
	} else {
	    if (subject.isReadOnly()) {
		cleanState();
		throw new LoginException ("Subject is Readonly");
	    } 
	    // add Principals to the Subject
	    if (!subject.getPrincipals().contains(userPrincipal))
		subject.getPrincipals().add(userPrincipal);
	    if (!subject.getPrincipals().contains(UIDPrincipal))
		subject.getPrincipals().add(UIDPrincipal);
	    if (!subject.getPrincipals().contains(GIDPrincipal))
		subject.getPrincipals().add(GIDPrincipal);
	    for (int i = 0; i < supplementaryGroups.size(); i++) {
		if (!subject.getPrincipals().contains
		    ((UnixNumericGroupPrincipal)supplementaryGroups.get(i)))
		    subject.getPrincipals().add((UnixNumericGroupPrincipal)
						supplementaryGroups.get(i));
	    }
	    
	    if (debug) {
		System.out.println("\t\t[JndiLoginModule]: " +
				   "added UnixPrincipal,");
		System.out.println("\t\t\t\tUnixNumericUserPrincipal,");
		System.out.println("\t\t\t\tUnixNumericGroupPrincipal(s),");
		System.out.println("\t\t\t to Subject");
	    }
	}
	// in any case, clean out state
	cleanState();
	commitSucceeded = true;
	return true;
    }

    /**
     * <p> This method is called if the LoginContext's
     * overall authentication failed.
     * (the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules
     * did not succeed).
     *
     * <p> If this LoginModule's own authentication attempt
     * succeeded (checked by retrieving the private state saved by the
     * <code>login</code> and <code>commit</code> methods),
     * then this method cleans up any state that was originally saved.
     *
     * <p>
     *
     * @exception LoginException if the abort fails.
     *
     * @return false if this LoginModule's own login and/or commit attempts
     *		failed, and true otherwise.
     */
    public boolean abort() throws LoginException {
	if (debug)
	    System.out.println("\t\t[JndiLoginModule]: " +
		"aborted authentication failed");

	if (succeeded == false) {
	    return false;
	} else if (succeeded == true && commitSucceeded == false) {

	    // Clean out state
	    succeeded = false;
	    cleanState();

	    userPrincipal = null;
	    UIDPrincipal = null;
	    GIDPrincipal = null;
	    supplementaryGroups = new LinkedList();
	} else {
	    // overall authentication succeeded and commit succeeded,
	    // but someone else's commit failed
	    logout();
	}
	return true;
    }

    /**
     * Logout a user.
     *
     * <p> This method removes the Principals
     * that were added by the <code>commit</code> method.
     *
     * <p>
     *
     * @exception LoginException if the logout fails.
     *
     * @return true in all cases since this <code>LoginModule</code>
     *		should not be ignored.
     */
    public boolean logout() throws LoginException {
	if (subject.isReadOnly()) {
	    cleanState();
	    throw new LoginException ("Subject is Readonly");
	}
	subject.getPrincipals().remove(userPrincipal);
	subject.getPrincipals().remove(UIDPrincipal);
	subject.getPrincipals().remove(GIDPrincipal);
	for (int i = 0; i < supplementaryGroups.size(); i++) {
	    subject.getPrincipals().remove
		((UnixNumericGroupPrincipal)supplementaryGroups.get(i));
	}
    
    
	// clean out state
	cleanState();
	succeeded = false;
	commitSucceeded = false;

	userPrincipal = null;
	UIDPrincipal = null;
	GIDPrincipal = null;
	supplementaryGroups = new LinkedList();

	if (debug) {
	    System.out.println("\t\t[JndiLoginModule]: " +
		"logged out Subject");
	}
	return true;
    }

    /**
     * Attempt authentication
     *
     * <p>
     *
     * @param getPasswdFromSharedState boolean that tells this method whether
     *		to retrieve the password from the sharedState.
     */
    private void attemptAuthentication(boolean getPasswdFromSharedState)
    throws LoginException {

	String encryptedPassword = null;

	// first get the username and password
	getUsernamePassword(getPasswdFromSharedState);
	
	try {

	    // get the user's passwd entry from the user provider URL
	    InitialContext iCtx = new InitialContext();
	    ctx = (DirContext)iCtx.lookup(userProvider);

	    /*
	    SearchControls controls = new SearchControls
					(SearchControls.ONELEVEL_SCOPE,
					0,
					5000,
					new String[] { USER_PWD },
					false,
					false);
	    */

	    SearchControls controls = new SearchControls();
	    NamingEnumeration ne = ctx.search("",
					"(uid=" + username + ")",
					controls);
	    if (ne.hasMore()) {
		SearchResult result = (SearchResult)ne.next();
		Attributes attributes = result.getAttributes();

		// get the password

		// this module works only if the LDAP directory server
		// is configured to permit read access to the userPassword
		// attribute. The directory administrator need to grant
		// this access.
		//
		// A workaround would be to make the server do authentication
		// by setting the Context.SECURITY_PRINCIPAL
		// and Context.SECURITY_CREDENTIALS property.
		// However, this would make it not work with systems that
		// don't do authentication at the server (like NIS).
		//
		// Setting the SECURITY_* properties and using "simple"
		// authentication for LDAP is recommended only for secure
		// channels. For nonsecure channels, SSL is recommended.

		Attribute pwd = attributes.get(USER_PWD);
		String encryptedPwd = new String((byte[])pwd.get(), "UTF8");
		encryptedPassword = encryptedPwd.substring(CRYPT.length());

		// check the password
		if (verifyPassword
		    (encryptedPassword, new String(password)) == true) {

		    // authentication succeeded
		    if (debug)
			System.out.println("\t\t[JndiLoginModule] " +
				"attemptAuthentication() succeeded");

		} else {
		    // authentication failed
		    if (debug)
			System.out.println("\t\t[JndiLoginModule] " +
				"attemptAuthentication() failed");
		    throw new FailedLoginException("Login incorrect");
		}

		// save input as shared state only if
		// authentication succeeded
		if (storePass &&
		    !sharedState.containsKey(NAME) &&
		    !sharedState.containsKey(PWD)) {
		    sharedState.put(NAME, username);
		    sharedState.put(PWD, password);
		}

		// create the user principal
		userPrincipal = new UnixPrincipal(username);

		// get the UID
		Attribute uid = attributes.get(USER_UID);
		String uidNumber = (String)uid.get();
		UIDPrincipal = new UnixNumericUserPrincipal(uidNumber);
		if (debug && uidNumber != null) {
		    System.out.println("\t\t[JndiLoginModule] " +
				"user: '" + username + "' has UID: " +
				uidNumber);
		}

		// get the GID
		Attribute gid = attributes.get(USER_GID);
		String gidNumber = (String)gid.get();
		GIDPrincipal = new UnixNumericGroupPrincipal
				(gidNumber, true);
		if (debug && gidNumber != null) {
		    System.out.println("\t\t[JndiLoginModule] " +
				"user: '" + username + "' has GID: " +
				gidNumber);
		}

		// get the supplementary groups from the group provider URL
		ctx = (DirContext)iCtx.lookup(groupProvider);
		ne = ctx.search("", new BasicAttributes("memberUid", username));

		while (ne.hasMore()) {
		    result = (SearchResult)ne.next();
		    attributes = result.getAttributes();

		    gid = attributes.get(GROUP_ID);
		    String suppGid = (String)gid.get();
		    if (!gidNumber.equals(suppGid)) {
			UnixNumericGroupPrincipal suppPrincipal =
			    new UnixNumericGroupPrincipal(suppGid, false);
			supplementaryGroups.add(suppPrincipal);
			if (debug && suppGid != null) {
			    System.out.println("\t\t[JndiLoginModule] " +
				"user: '" + username +
				"' has Supplementary Group: " +
				suppGid);
			}
		    }
		}

	    } else {
		// bad username
		if (debug) {
		    System.out.println("\t\t[JndiLoginModule]: User not found");
		}
		throw new FailedLoginException("User not found");
	    }
	} catch (NamingException ne) {
	    // bad username
	    if (debug) {
		System.out.println("\t\t[JndiLoginModule]:  User not found");
		ne.printStackTrace();
	    }
	    throw new FailedLoginException("User not found");
	} catch (java.io.UnsupportedEncodingException uee) {
	    // password stored in incorrect format
	    if (debug) {
		System.out.println("\t\t[JndiLoginModule]:  " +
				"password incorrectly encoded");
		uee.printStackTrace();
	    }
	    throw new LoginException("Login failure due to incorrect " +
				"password encoding in the password database");
	}

	// authentication succeeded
    }
 
    /**
     * Get the username and password.
     * This method does not return any value.
     * Instead, it sets global name and password variables.
     *
     * <p> Also note that this method will set the username and password
     * values in the shared state in case subsequent LoginModules
     * want to use them via use/tryFirstPass.
     *
     * <p>
     *
     * @param getPasswdFromSharedState boolean that tells this method whether
     *		to retrieve the password from the sharedState.
     */
    private void getUsernamePassword(boolean getPasswdFromSharedState)
    throws LoginException {

	if (getPasswdFromSharedState) {
	    // use the password saved by the first module in the stack
	    username = (String)sharedState.get(NAME);
	    password = (char[])sharedState.get(PWD);
	    return;
	}

	// prompt for a username and password
        if (callbackHandler == null)
	    throw new LoginException("Error: no CallbackHandler available " +
		"to garner authentication information from the user");

	String protocol = userProvider.substring(0, userProvider.indexOf(":"));

	Callback[] callbacks = new Callback[2];
	callbacks[0] = new NameCallback(protocol + " " 
					    + rb.getString("username: "));
	callbacks[1] = new PasswordCallback(protocol + " " +
 					        rb.getString("password: "),
					    false);

	try {
	    callbackHandler.handle(callbacks);
	    username = ((NameCallback)callbacks[0]).getName();
	    char[] tmpPassword = ((PasswordCallback)callbacks[1]).getPassword();
	    password = new char[tmpPassword.length];
	    System.arraycopy(tmpPassword, 0,
				password, 0, tmpPassword.length);
	    ((PasswordCallback)callbacks[1]).clearPassword();

	} catch (java.io.IOException ioe) {
	    throw new LoginException(ioe.toString());
	} catch (UnsupportedCallbackException uce) {
	    throw new LoginException("Error: " + uce.getCallback().toString() +
			" not available to garner authentication information " +
			"from the user");
	}

	// print debugging information
	if (strongDebug) {
	    System.out.println("\t\t[JndiLoginModule] " +
				"user entered username: " +
				username);
	    System.out.print("\t\t[JndiLoginModule] " +
				"user entered password: ");
	    for (int i = 0; i < password.length; i++)
		System.out.print(password[i]);
	    System.out.println();
	}
    }

    /**
     * Verify a password against the encrypted passwd from /etc/shadow
     */
    private boolean verifyPassword(String encryptedPassword, String password) {

	if (encryptedPassword == null)
	    return false;

	Crypt c = new Crypt();
	try {
	    byte oldCrypt[] = encryptedPassword.getBytes("UTF8");
	    byte newCrypt[] = c.crypt(password.getBytes("UTF8"),
				      oldCrypt);
	    if (newCrypt.length != oldCrypt.length)
	        return false;
	    for (int i = 0; i < newCrypt.length; i++) {
	        if (oldCrypt[i] != newCrypt[i])
		    return false;
	    }
	} catch (java.io.UnsupportedEncodingException uee) {
	    // cannot happen, but return false just to be safe
	    return false;
	}
	return true;
    }

    /**
     * Clean out state because of a failed authentication attempt
     */
    private void cleanState() {
	username = null;
	if (password != null) {
	    for (int i = 0; i < password.length; i++)
		password[i] = ' ';
	    password = null;
	}
	ctx = null;

	if (clearPass) {
	    sharedState.remove(NAME);
	    sharedState.remove(PWD);
	}
    }
}