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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package com.sun.security.auth.module;

import java.io.*;
import java.text.MessageFormat;
import java.util.*;

import javax.security.auth.*;
import javax.security.auth.kerberos.*;
import javax.security.auth.callback.*;
import javax.security.auth.login.*;
import javax.security.auth.spi.*;

import sun.security.krb5.*;
import sun.security.jgss.krb5.Krb5Util;
import sun.security.krb5.Credentials;
import sun.misc.HexDumpEncoder;

 This LoginModule authenticates users using
Kerberos protocols.
 The configuration entry for Krb5LoginModule has
several options that control the authentication process and
additions to the Subject's private credential
set. Irrespective of these options, the Subject's
principal set and private credentials set are updated only when
commit is called.
When commit is called, the KerberosPrincipal
is added to the  Subject's
principal set and KerberosTicket is
added to the Subject's private credentials.
 If the configuration entry for KerberosLoginModule
has the option storeKey set to true, then
KerberosKey will also be added to the
subject's private credentials. KerberosKey, the principal's
key will be either obtained from the keytab or
derived from user's password.
 This LoginModule recognizes the doNotPrompt
option. If set to true the user will not be prompted for the password.
 The user can  specify the location of the ticket cache by using
the option ticketCache in the configuration entry.
The user can specify the keytab location by using
the option keyTab
in the configuration entry.
 The principal name can be specified in the configuration entry
by using the option principal. The principal name
can either be a simple user name or a service name such as
host/mission.eng.sun.com. The principal can also
be set using the system property sun.security.krb5.principal.
This property is checked during login. If this property is not set, then
the principal name from the configuration is used. In the
case where the principal property is not set and the principal
entry also does not exist, the user is prompted for the name.
When this property of entry is set, and useTicketCache
is set to true, only TGT belonging to this principal is used.
 The following is a list of configuration options supported
for Krb5LoginModule:

refreshKrb5Config:
 Set this to true, if you want the configuration
to be refreshed before the login method is called.

useTicketCache:
Set this to true, if you want the
TGT to be obtained
from the ticket cache. Set this option
to false if you do not want this module to use the ticket cache.
(Default is False).
This module will
search for the ticket
cache in the following locations:
On Solaris and Linux
it will look for the ticket cache in /tmp/krb5cc_uid
where the uid is numeric user
identifier. If the ticket cache is
not available in the above location, or if we are on a
Windows platform, it will look for the cache as
{user.home}{file.separator}krb5cc_{user.name}.
You can override the ticket cache location by using
ticketCache.
For Windows, if a ticket cannot be retrieved from the file ticket cache,
it will use Local Security Authority (LSA) API to get the TGT.

ticketCache:
Set this to the name of the ticket
cache that  contains user's TGT.
If this is set,  useTicketCache
must also be set to true; Otherwise a configuration error will
be returned.
 

renewTGT:
Set this to true, if you want to renew the TGT when it's more than half-way expired (the time until expiration is less than the time since start time). If this is set, useTicketCache must also be set to true; otherwise a configuration error will be returned.

doNotPrompt:
Set this to true if you do not want to be
prompted for the password
if credentials can not be obtained from the cache, the keytab,
or through shared state.(Default is false)
If set to true, credential must be obtained through cache, keytab,
or shared state. Otherwise, authentication will fail.

useKeyTab:
Set this to true if you
want the module to get the principal's key from the
the keytab.(default value is False)
If keytab
is not set then
the module will locate the keytab from the
Kerberos configuration file.
If it is not specified in the Kerberos configuration file
then it will look for the file
{user.home}{file.separator}krb5.keytab.

keyTab:
Set this to the file name of the
keytab to get principal's secret key.

storeKey:
Set this to true to if you want the
principal's key to be stored in the Subject's private credentials. 

principal:
The name of the principal that should
be used. The principal can be a simple username such as
"testuser" or a service name such as
"host/testhost.eng.sun.com". You can use the
principal  option to set the principal when there are
credentials for multiple principals in the
keyTab or when you want a specific ticket cache only.
The principal can also be set using the system property
sun.security.krb5.principal. In addition, if this
system property is defined, then it will be used. If this property
is not set, then the principal name from the configuration will be
used.

isInitiator:
Set this to true, if initiator. Set this to false, if acceptor only.
(Default is true).
Note: Do not set this value to false for initiators.

 This LoginModule also recognizes the following additional
Configuration
options that enable you to share username and passwords across different
authentication modules:
   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
                  modules 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 LoginModule clears the
                  username and password stored in the module's shared
                  state  after both phases of authentication
                  (login and commit) have completed.

If the principal system property or key is already provided, the value of
"javax.security.auth.login.name" in the shared state is ignored.
When multiple mechanisms to retrieve a ticket or key is provided, the
preference order looks like this:

ticket cache
keytab
shared state
user prompt

Note that if any step fails, it will fallback to the next step.
There's only one exception, it the shared state step fails and
useFirstPass=true, no user prompt is made.
Examples of some configuration values for Krb5LoginModule in
JAAS config file and the results are:

 doNotPrompt=true;

 This is an illegal combination since none of useTicketCache,
useKeyTab, useFirstPass and tryFirstPass
is set and the user can not be prompted for the password.

 ticketCache = <filename>;

 This is an illegal combination since useTicketCache
is not set to true and the ticketCache is set. A configuration error
will occur.

 renewTGT=true;

 This is an illegal combination since useTicketCache is
not set to true and renewTGT is set. A configuration error will occur.

 storeKey=true
useTicketCache = true
doNotPrompt=true;;

 This is an illegal combination since  storeKey is set to
true but the key can not be obtained either by prompting the user or from
the keytab, or from the shared state. A configuration error will occur.

  keyTab = <filename> doNotPrompt=true ;

This is an illegal combination since useKeyTab is not set to true and
the keyTab is set. A configuration error will occur.

 debug=true 

 Prompt the user for the principal name and the password.
Use the authentication exchange to get TGT from the KDC and
populate the Subject with the principal and TGT.
Output debug messages.

 useTicketCache = true doNotPrompt=true;

Check the default cache for TGT and populate the Subject
with the principal and TGT. If the TGT is not available,
do not prompt the user, instead fail the authentication.

principal=<name>useTicketCache = true
doNotPrompt=true;

 Get the TGT from the default cache for the principal and populate the
Subject's principal and private creds set. If ticket cache is
not available or does not contain the principal's TGT
authentication will fail.

 useTicketCache = true
ticketCache=<file name>useKeyTab = true
 keyTab=<keytab filename>
principal = <principal name>
doNotPrompt=true;

  Search the cache for the principal's TGT. If it is not available
use the key in the keytab to perform authentication exchange with the
KDC and acquire the TGT.
The Subject will be populated with the principal and the TGT.
If the key is not available or valid then authentication will fail.

useTicketCache = true
ticketCache=<file name>

 The TGT will be obtained from the cache specified.
The Kerberos principal name used will be the principal name in
the Ticket cache. If the TGT is not available in the
ticket cache the user will be prompted for the principal name
and the password. The TGT will be obtained using the authentication
exchange with the KDC.
The Subject will be populated with the TGT.

 useKeyTab = true
keyTab=<keytab filename>
principal= <principal name>
storeKey=true;

  The key for the principal will be retrieved from the keytab.
If the key is not available in the keytab the user will be prompted
for the principal's password. The Subject will be populated
with the principal's key either from the keytab or derived from the
password entered.

 useKeyTab = true
keyTab=<keytabname>
storeKey=true
doNotPrompt=true;

The user will be prompted for the service principal name.
If the principal's
longterm key is available in the keytab , it will be added to the
Subject's private credentials. An authentication exchange will be
attempted with the principal name and the key from the Keytab.
If successful the TGT will be added to the
Subject's private credentials set. Otherwise the authentication will
fail.


useTicketCache=true
ticketCache=<file name>;
useKeyTab = true
keyTab=<file name> storeKey=true
principal= <principal name>


The client's TGT will be retrieved from the ticket cache and added to the
Subject's private credentials. If the TGT is not available
in the ticket cache, or the TGT's client name does not match the principal
name, Java will use a secret key to obtain the TGT using the authentication
exchange and added to the Subject's private credentials.
This secret key will be first retrieved from the keytab. If the key
is not available, the user will be prompted for the password. In either
case, the key derived from the password will be added to the
Subject's private credentials set.

isInitiator = false

Configured to act as acceptor only, credentials are not acquired
via AS exchange. For acceptors only, set this value to false.
For initiators, do not set this value to false.

isInitiator = true

Configured to act as initiator, credentials are acquired
via AS exchange. For initiators, set this value to true, or leave this
option unset, in which case default value (true) will be used.
Author:
Ram Marti/**
 * <p> This <code>LoginModule</code> authenticates users using
 * Kerberos protocols.
 *
 * <p> The configuration entry for <code>Krb5LoginModule</code> has
 * several options that control the authentication process and
 * additions to the <code>Subject</code>'s private credential
 * set. Irrespective of these options, the <code>Subject</code>'s
 * principal set and private credentials set are updated only when
 * <code>commit</code> is called.
 * When <code>commit</code> is called, the <code>KerberosPrincipal</code>
 * is added to the  <code>Subject</code>'s
 * principal set and <code>KerberosTicket</code> is
 * added to the <code>Subject</code>'s private credentials.
 *
 * <p> If the configuration entry for <code>KerberosLoginModule</code>
 * has the option <code>storeKey</code> set to true, then
 * <code>KerberosKey</code> will also be added to the
 * subject's private credentials. <code>KerberosKey</code>, the principal's
 * key will be either obtained from the keytab or
 * derived from user's password.
 *
 * <p> This <code>LoginModule</code> recognizes the <code>doNotPrompt</code>
 * option. If set to true the user will not be prompted for the password.
 *
 * <p> The user can  specify the location of the ticket cache by using
 * the option <code>ticketCache</code> in the configuration entry.
 *
 * <p>The user can specify the keytab location by using
 * the option <code>keyTab</code>
 * in the configuration entry.
 *
 * <p> The principal name can be specified in the configuration entry
 * by using the option <code>principal</code>. The principal name
 * can either be a simple user name or a service name such as
 * <code>host/mission.eng.sun.com</code>. The principal can also
 * be set using the system property <code>sun.security.krb5.principal</code>.
 * This property is checked during login. If this property is not set, then
 * the principal name from the configuration is used. In the
 * case where the principal property is not set and the principal
 * entry also does not exist, the user is prompted for the name.
 * When this property of entry is set, and <code>useTicketCache</code>
 * is set to true, only TGT belonging to this principal is used.
 *
 * <p> The following is a list of configuration options supported
 * for <code>Krb5LoginModule</code>:
 * <dl>
 * <blockquote><dt><b><code>refreshKrb5Config</code></b>:</dt>
 * <dd> Set this to true, if you want the configuration
 * to be refreshed before the <code>login</code> method is called.</dd>
 * <P>
 * <dt><b><code>useTicketCache</code></b>:</dt>
 * <dd>Set this to true, if you want the
 * TGT to be obtained
 * from the ticket cache. Set this option
 * to false if you do not want this module to use the ticket cache.
 * (Default is False).
 * This module will
 * search for the ticket
 * cache in the following locations:
 * On Solaris and Linux
 * it will look for the ticket cache in /tmp/krb5cc_<code>uid</code>
 * where the uid is numeric user
 * identifier. If the ticket cache is
 * not available in the above location, or if we are on a
 * Windows platform, it will look for the cache as
 * {user.home}{file.separator}krb5cc_{user.name}.
 * You can override the ticket cache location by using
 * <code>ticketCache</code>.
 * For Windows, if a ticket cannot be retrieved from the file ticket cache,
 * it will use Local Security Authority (LSA) API to get the TGT.
 * <P>
 * <dt><b><code>ticketCache</code></b>:</dt>
 * <dd>Set this to the name of the ticket
 * cache that  contains user's TGT.
 * If this is set,  <code>useTicketCache</code>
 * must also be set to true; Otherwise a configuration error will
 * be returned.</dd>
 *  <P>
 * <dt><b><code>renewTGT</code></b>:</dt>
 * <dd>Set this to true, if you want to renew the TGT when it's more than
 * half-way expired (the time until expiration is less than the time
 * since start time). If this is set, {@code useTicketCache} must also be
 * set to true; otherwise a configuration error will be returned.</dd>
 * <p>
 * <dt><b><code>doNotPrompt</code></b>:</dt>
 * <dd>Set this to true if you do not want to be
 * prompted for the password
 * if credentials can not be obtained from the cache, the keytab,
 * or through shared state.(Default is false)
 * If set to true, credential must be obtained through cache, keytab,
 * or shared state. Otherwise, authentication will fail.</dd>
 * <P>
 * <dt><b><code>useKeyTab</code></b>:</dt>
 * <dd>Set this to true if you
 * want the module to get the principal's key from the
 * the keytab.(default value is False)
 * If <code>keytab</code>
 * is not set then
 * the module will locate the keytab from the
 * Kerberos configuration file.
 * If it is not specified in the Kerberos configuration file
 * then it will look for the file
 * <code>{user.home}{file.separator}</code>krb5.keytab.</dd>
 * <P>
 * <dt><b><code>keyTab</code></b>:</dt>
 * <dd>Set this to the file name of the
 * keytab to get principal's secret key.</dd>
 * <P>
 * <dt><b><code>storeKey</code></b>:</dt>
 * <dd>Set this to true to if you want the
 * principal's key to be stored in the Subject's private credentials. </dd>
 * <p>
 * <dt><b><code>principal</code></b>:</dt>
 * <dd>The name of the principal that should
 * be used. The principal can be a simple username such as
 * "<code>testuser</code>" or a service name such as
 * "<code>host/testhost.eng.sun.com</code>". You can use the
 * <code>principal</code>  option to set the principal when there are
 * credentials for multiple principals in the
 * <code>keyTab</code> or when you want a specific ticket cache only.
 * The principal can also be set using the system property
 * <code>sun.security.krb5.principal</code>. In addition, if this
 * system property is defined, then it will be used. If this property
 * is not set, then the principal name from the configuration will be
 * used.</dd>
 * <P>
 * <dt><b><code>isInitiator</code></b>:</dt>
 * <dd>Set this to true, if initiator. Set this to false, if acceptor only.
 * (Default is true).
 * Note: Do not set this value to false for initiators.</dd>
 * </dl></blockquote>
 *
 * <p> This <code>LoginModule</code> also recognizes the following additional
 * <code>Configuration</code>
 * options that enable you to share username and passwords across different
 * authentication modules:
 * <pre>
 *
 *    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
 *                   modules 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 LoginModule clears the
 *                   username and password stored in the module's shared
 *                   state  after both phases of authentication
 *                   (login and commit) have completed.
 * </pre>
 * <p>If the principal system property or key is already provided, the value of
 * "javax.security.auth.login.name" in the shared state is ignored.
 * <p>When multiple mechanisms to retrieve a ticket or key is provided, the
 * preference order looks like this:
 * <ol>
 * <li>ticket cache
 * <li>keytab
 * <li>shared state
 * <li>user prompt
 * </ol>
 * <p>Note that if any step fails, it will fallback to the next step.
 * There's only one exception, it the shared state step fails and
 * <code>useFirstPass</code>=true, no user prompt is made.
 * <p>Examples of some configuration values for Krb5LoginModule in
 * JAAS config file and the results are:
 * <ul>
 * <p> <code>doNotPrompt</code>=true;
 * </ul>
 * <p> This is an illegal combination since none of <code>useTicketCache</code>,
 * <code>useKeyTab</code>, <code>useFirstPass</code> and <code>tryFirstPass</code>
 * is set and the user can not be prompted for the password.
 *<ul>
 * <p> <code>ticketCache</code> = &lt;filename&gt;;
 *</ul>
 * <p> This is an illegal combination since <code>useTicketCache</code>
 * is not set to true and the ticketCache is set. A configuration error
 * will occur.
 * <ul>
 * <p> <code>renewTGT</code>=true;
 *</ul>
 * <p> This is an illegal combination since <code>useTicketCache</code> is
 * not set to true and renewTGT is set. A configuration error will occur.
 * <ul>
 * <p> <code>storeKey</code>=true
 * <code>useTicketCache</code> = true
 * <code>doNotPrompt</code>=true;;
 *</ul>
 * <p> This is an illegal combination since  <code>storeKey</code> is set to
 * true but the key can not be obtained either by prompting the user or from
 * the keytab, or from the shared state. A configuration error will occur.
 * <ul>
 * <p>  <code>keyTab</code> = &lt;filename&gt; <code>doNotPrompt</code>=true ;
 * </ul>
 * <p>This is an illegal combination since useKeyTab is not set to true and
 * the keyTab is set. A configuration error will occur.
 * <ul>
 * <p> <code>debug=true </code>
 *</ul>
 * <p> Prompt the user for the principal name and the password.
 * Use the authentication exchange to get TGT from the KDC and
 * populate the <code>Subject</code> with the principal and TGT.
 * Output debug messages.
 * <ul>
 * <p> <code>useTicketCache</code> = true <code>doNotPrompt</code>=true;
 *</ul>
 * <p>Check the default cache for TGT and populate the <code>Subject</code>
 * with the principal and TGT. If the TGT is not available,
 * do not prompt the user, instead fail the authentication.
 * <ul>
 * <p><code>principal</code>=&lt;name&gt;<code>useTicketCache</code> = true
 * <code>doNotPrompt</code>=true;
 *</ul>
 * <p> Get the TGT from the default cache for the principal and populate the
 * Subject's principal and private creds set. If ticket cache is
 * not available or does not contain the principal's TGT
 * authentication will fail.
 * <ul>
 * <p> <code>useTicketCache</code> = true
 * <code>ticketCache</code>=&lt;file name&gt;<code>useKeyTab</code> = true
 * <code> keyTab</code>=&lt;keytab filename&gt;
 * <code>principal</code> = &lt;principal name&gt;
 * <code>doNotPrompt</code>=true;
 *</ul>
 * <p>  Search the cache for the principal's TGT. If it is not available
 * use the key in the keytab to perform authentication exchange with the
 * KDC and acquire the TGT.
 * The Subject will be populated with the principal and the TGT.
 * If the key is not available or valid then authentication will fail.
 * <ul>
 * <p><code>useTicketCache</code> = true
 * <code>ticketCache</code>=&lt;file name&gt;
 *</ul>
 * <p> The TGT will be obtained from the cache specified.
 * The Kerberos principal name used will be the principal name in
 * the Ticket cache. If the TGT is not available in the
 * ticket cache the user will be prompted for the principal name
 * and the password. The TGT will be obtained using the authentication
 * exchange with the KDC.
 * The Subject will be populated with the TGT.
 *<ul>
 * <p> <code>useKeyTab</code> = true
 * <code>keyTab</code>=&lt;keytab filename&gt;
 * <code>principal</code>= &lt;principal name&gt;
 * <code>storeKey</code>=true;
 *</ul>
 * <p>  The key for the principal will be retrieved from the keytab.
 * If the key is not available in the keytab the user will be prompted
 * for the principal's password. The Subject will be populated
 * with the principal's key either from the keytab or derived from the
 * password entered.
 * <ul>
 * <p> <code>useKeyTab</code> = true
 * <code>keyTab</code>=&lt;keytabname&gt;
 * <code>storeKey</code>=true
 * <code>doNotPrompt</code>=true;
 *</ul>
 * <p>The user will be prompted for the service principal name.
 * If the principal's
 * longterm key is available in the keytab , it will be added to the
 * Subject's private credentials. An authentication exchange will be
 * attempted with the principal name and the key from the Keytab.
 * If successful the TGT will be added to the
 * Subject's private credentials set. Otherwise the authentication will
 * fail.
 *<ul>
 * <p>
 * <code>useTicketCache</code>=true
 * <code>ticketCache</code>=&lt;file name&gt;;
 * <code>useKeyTab</code> = true
 * <code>keyTab</code>=&lt;file name&gt; <code>storeKey</code>=true
 * <code>principal</code>= &lt;principal name&gt;
 *</ul>
 * <p>
 * The client's TGT will be retrieved from the ticket cache and added to the
 * <code>Subject</code>'s private credentials. If the TGT is not available
 * in the ticket cache, or the TGT's client name does not match the principal
 * name, Java will use a secret key to obtain the TGT using the authentication
 * exchange and added to the Subject's private credentials.
 * This secret key will be first retrieved from the keytab. If the key
 * is not available, the user will be prompted for the password. In either
 * case, the key derived from the password will be added to the
 * Subject's private credentials set.
 * <ul>
 * <p><code>isInitiator</code> = false
 *</ul>
 * <p>Configured to act as acceptor only, credentials are not acquired
 * via AS exchange. For acceptors only, set this value to false.
 * For initiators, do not set this value to false.
 * <ul>
 * <p><code>isInitiator</code> = true
 *</ul>
 * <p>Configured to act as initiator, credentials are acquired
 * via AS exchange. For initiators, set this value to true, or leave this
 * option unset, in which case default value (true) will be used.
 *
 * @author Ram Marti
 */

public class Krb5LoginModule implements LoginModule {

    // initial state
    private Subject subject;
    private CallbackHandler callbackHandler;
    private Map<String, Object> sharedState;
    private Map<String, ?> options;

    // configurable option
    private boolean debug = false;
    private boolean storeKey = false;
    private boolean doNotPrompt = false;
    private boolean useTicketCache = false;
    private boolean useKeyTab = false;
    private String ticketCacheName = null;
    private String keyTabName = null;
    private String princName = null;

    private boolean useFirstPass = false;
    private boolean tryFirstPass = false;
    private boolean storePass = false;
    private boolean clearPass = false;
    private boolean refreshKrb5Config = false;
    private boolean renewTGT = false;

    // specify if initiator.
    // perform authentication exchange if initiator
    private boolean isInitiator = true;

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

    // Encryption keys calculated from password. Assigned when storekey == true
    // and useKeyTab == false (or true but not found)
    private EncryptionKey[] encKeys = null;

    KeyTab ktab = null;

    private Credentials cred = null;

    private PrincipalName principal = null;
    private KerberosPrincipal kerbClientPrinc = null;
    private KerberosTicket kerbTicket = null;
    private KerberosKey[] kerbKeys = null;
    private StringBuffer krb5PrincName = null;
    private char[] password = null;

    private static final String NAME = "javax.security.auth.login.name";
    private static final String PWD = "javax.security.auth.login.password";
    static final java.util.ResourceBundle rb =
        java.util.ResourceBundle.getBundle("sun.security.util.AuthResources");

    
Initialize this LoginModule.

Params:
subject – the Subject to be authenticated. 
callbackHandler – a CallbackHandler for
                 communication with the end user (prompting for
                 usernames and passwords, for example). 
sharedState – shared LoginModule state. 
options – options specified in the login
                 Configuration for this particular
                 LoginModule./**
     * Initialize this <code>LoginModule</code>.
     *
     * <p>
     * @param subject the <code>Subject</code> to be authenticated. <p>
     *
     * @param callbackHandler a <code>CallbackHandler</code> for
     *                  communication 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>.
     */
    // Unchecked warning from (Map<String, Object>)sharedState is safe
    // since javax.security.auth.login.LoginContext passes a raw HashMap.
    // Unchecked warnings from options.get(String) are safe since we are
    // passing known keys.
    @SuppressWarnings("unchecked")
    public void initialize(Subject subject,
                           CallbackHandler callbackHandler,
                           Map<String, ?> sharedState,
                           Map<String, ?> options) {

        this.subject = subject;
        this.callbackHandler = callbackHandler;
        this.sharedState = (Map<String, Object>)sharedState;
        this.options = options;

        // initialize any configured options

        debug = "true".equalsIgnoreCase((String)options.get("debug"));
        storeKey = "true".equalsIgnoreCase((String)options.get("storeKey"));
        doNotPrompt = "true".equalsIgnoreCase((String)options.get
                                              ("doNotPrompt"));
        useTicketCache = "true".equalsIgnoreCase((String)options.get
                                                 ("useTicketCache"));
        useKeyTab = "true".equalsIgnoreCase((String)options.get("useKeyTab"));
        ticketCacheName = (String)options.get("ticketCache");
        keyTabName = (String)options.get("keyTab");
        if (keyTabName != null) {
            keyTabName = sun.security.krb5.internal.ktab.KeyTab.normalize(
                         keyTabName);
        }
        princName = (String)options.get("principal");
        refreshKrb5Config =
            "true".equalsIgnoreCase((String)options.get("refreshKrb5Config"));
        renewTGT =
            "true".equalsIgnoreCase((String)options.get("renewTGT"));

        // check isInitiator value
        String isInitiatorValue = ((String)options.get("isInitiator"));
        if (isInitiatorValue == null) {
            // use default, if value not set
        } else {
            isInitiator = "true".equalsIgnoreCase(isInitiatorValue);
        }

        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"));
        if (debug) {
            System.out.print("Debug is  " + debug
                             + " storeKey " + storeKey
                             + " useTicketCache " + useTicketCache
                             + " useKeyTab " + useKeyTab
                             + " doNotPrompt " + doNotPrompt
                             + " ticketCache is " + ticketCacheName
                             + " isInitiator " + isInitiator
                             + " KeyTab is " + keyTabName
                             + " refreshKrb5Config is " + refreshKrb5Config
                             + " principal is " + princName
                             + " tryFirstPass is " + tryFirstPass
                             + " useFirstPass is " + useFirstPass
                             + " storePass is " + storePass
                             + " clearPass is " + clearPass + "\n");
        }
    }


    
Authenticate the user

Throws:
FailedLoginException – if the authentication fails. 
LoginException – if this LoginModule
         is unable to perform the authentication.
Returns:
true in all cases since this LoginModule
         should not be ignored./**
     * Authenticate the user
     *
     * <p>
     *
     * @return true in all cases 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 {

        int len;
        validateConfiguration();
        if (refreshKrb5Config) {
            try {
                if (debug) {
                    System.out.println("Refreshing Kerberos configuration");
                }
                sun.security.krb5.Config.refresh();
            } catch (KrbException ke) {
                LoginException le = new LoginException(ke.getMessage());
                le.initCause(ke);
                throw le;
            }
        }
        String principalProperty = System.getProperty
            ("sun.security.krb5.principal");
        if (principalProperty != null) {
            krb5PrincName = new StringBuffer(principalProperty);
        } else {
            if (princName != null) {
                krb5PrincName = new StringBuffer(princName);
            }
        }

        if (tryFirstPass) {
            try {
                attemptAuthentication(true);
                if (debug)
                    System.out.println("\t\t[Krb5LoginModule] " +
                                       "authentication succeeded");
                succeeded = true;
                cleanState();
                return true;
            } catch (LoginException le) {
                // authentication failed -- try again below by prompting
                cleanState();
                if (debug) {
                    System.out.println("\t\t[Krb5LoginModule] " +
                                       "tryFirstPass failed with:" +
                                       le.getMessage());
                }
            }
        } else if (useFirstPass) {
            try {
                attemptAuthentication(true);
                succeeded = true;
                cleanState();
                return true;
            } catch (LoginException e) {
                // authentication failed -- clean out state
                if (debug) {
                    System.out.println("\t\t[Krb5LoginModule] " +
                                       "authentication failed \n" +
                                       e.getMessage());
                }
                succeeded = false;
                cleanState();
                throw e;
            }
        }

        // attempt the authentication by getting the username and pwd
        // by prompting or configuration i.e. not from shared state

        try {
            attemptAuthentication(false);
            succeeded = true;
            cleanState();
            return true;
        } catch (LoginException e) {
            // authentication failed -- clean out state
            if (debug) {
                System.out.println("\t\t[Krb5LoginModule] " +
                                   "authentication failed \n" +
                                   e.getMessage());
            }
            succeeded = false;
            cleanState();
            throw e;
        }
    }
    
process the configuration options
Get the TGT either out of
cache or from the KDC using the password entered
Check the  permission before getting the TGT
/**
     * process the configuration options
     * Get the TGT either out of
     * cache or from the KDC using the password entered
     * Check the  permission before getting the TGT
     */

    private void attemptAuthentication(boolean getPasswdFromSharedState)
        throws LoginException {

        /*
         * Check the creds cache to see whether
         * we have TGT for this client principal
         */
        if (krb5PrincName != null) {
            try {
                principal = new PrincipalName
                    (krb5PrincName.toString(),
                     PrincipalName.KRB_NT_PRINCIPAL);
            } catch (KrbException e) {
                LoginException le = new LoginException(e.getMessage());
                le.initCause(e);
                throw le;
            }
        }

        try {
            if (useTicketCache) {
                // ticketCacheName == null implies the default cache
                if (debug)
                    System.out.println("Acquire TGT from Cache");
                cred  = Credentials.acquireTGTFromCache
                    (principal, ticketCacheName);

                if (cred != null) {
                    if (renewTGT && isOld(cred)) {
                        // renew if ticket is old.
                        Credentials newCred = renewCredentials(cred);
                        if (newCred != null) {
                            cred = newCred;
                        }
                    }
                    if (!isCurrent(cred)) {
                        // credentials have expired
                        cred = null;
                        if (debug)
                            System.out.println("Credentials are" +
                                    " no longer valid");
                    }
                }

                if (cred != null) {
                   // get the principal name from the ticket cache
                   if (principal == null) {
                        principal = cred.getClient();
                   }
                }
                if (debug) {
                    System.out.println("Principal is " + principal);
                    if (cred == null) {
                        System.out.println
                            ("null credentials from Ticket Cache");
                    }
                }
            }

            // cred = null indicates that we didn't get the creds
            // from the cache or useTicketCache was false

            if (cred == null) {
                // We need the principal name whether we use keytab
                // or AS Exchange
                if (principal == null) {
                    promptForName(getPasswdFromSharedState);
                    principal = new PrincipalName
                        (krb5PrincName.toString(),
                         PrincipalName.KRB_NT_PRINCIPAL);
                }

                /*
                 * Before dynamic KeyTab support (6894072), here we check if
                 * the keytab contains keys for the principal. If no, keytab
                 * will not be used and password is prompted for.
                 *
                 * After 6894072, we normally don't check it, and expect the
                 * keys can be populated until a real connection is made. The
                 * check is still done when isInitiator == true, where the keys
                 * will be used right now.
                 *
                 * Probably tricky relations:
                 *
                 * useKeyTab is config flag, but when it's true but the ktab
                 * does not contains keys for principal, we would use password
                 * and keep the flag unchanged (for reuse?). In this method,
                 * we use (ktab != null) to check whether keytab is used.
                 * After this method (and when storeKey == true), we use
                 * (encKeys == null) to check.
                 */
                if (useKeyTab) {
                    ktab = (keyTabName == null)
                                ? KeyTab.getInstance()
                                : KeyTab.getInstance(new File(keyTabName));
                    if (isInitiator) {
                        if (Krb5Util.keysFromJavaxKeyTab(ktab, principal).length
                                == 0) {
                            ktab = null;
                            if (debug) {
                                System.out.println
                                    ("Key for the principal " +
                                     principal  +
                                     " not available in " +
                                     ((keyTabName == null) ?
                                      "default key tab" : keyTabName));
                            }
                        }
                    }
                }

                KrbAsReqBuilder builder;

                if (ktab == null) {
                    promptForPass(getPasswdFromSharedState);
                    builder = new KrbAsReqBuilder(principal, password);
                    if (isInitiator) {
                        // XXX Even if isInitiator=false, it might be
                        // better to do an AS-REQ so that keys can be
                        // updated with PA info
                        cred = builder.action().getCreds();
                    }
                    if (storeKey) {
                        encKeys = builder.getKeys(isInitiator);
                        // When encKeys is empty, the login actually fails.
                        // For compatibility, exception is thrown in commit().
                    }
                } else {
                    builder = new KrbAsReqBuilder(principal, ktab);
                    if (isInitiator) {
                        cred = builder.action().getCreds();
                    }
                }
                builder.destroy();

                if (debug) {
                    System.out.println("principal is " + principal);
                    HexDumpEncoder hd = new HexDumpEncoder();
                    if (ktab != null) {
                        System.out.println("Will use keytab");
                    } else if (storeKey) {
                        for (int i = 0; i < encKeys.length; i++) {
                            System.out.println("EncryptionKey: keyType=" +
                                encKeys[i].getEType() +
                                " keyBytes (hex dump)=" +
                                hd.encodeBuffer(encKeys[i].getBytes()));
                        }
                    }
                }

                // we should hava a non-null cred
                if (isInitiator && (cred == null)) {
                    throw new LoginException
                        ("TGT Can not be obtained from the KDC ");
                }

            }
        } catch (KrbException e) {
            LoginException le = new LoginException(e.getMessage());
            le.initCause(e);
            throw le;
        } catch (IOException ioe) {
            LoginException ie = new LoginException(ioe.getMessage());
            ie.initCause(ioe);
            throw ie;
        }
    }

    private void promptForName(boolean getPasswdFromSharedState)
        throws LoginException {
        krb5PrincName = new StringBuffer("");
        if (getPasswdFromSharedState) {
            // use the name saved by the first module in the stack
            username = (String)sharedState.get(NAME);
            if (debug) {
                System.out.println
                    ("username from shared state is " + username + "\n");
            }
            if (username == null) {
                System.out.println
                    ("username from shared state is null\n");
                throw new LoginException
                    ("Username can not be obtained from sharedstate ");
            }
            if (debug) {
                System.out.println
                    ("username from shared state is " + username + "\n");
            }
            if (username != null && username.length() > 0) {
                krb5PrincName.insert(0, username);
                return;
            }
        }

        if (doNotPrompt) {
            throw new LoginException
                ("Unable to obtain Princpal Name for authentication ");
        } else {
            if (callbackHandler == null)
                throw new LoginException("No CallbackHandler "
                                         + "available "
                                         + "to garner authentication "
                                         + "information from the user");
            try {
                String defUsername = System.getProperty("user.name");

                Callback[] callbacks = new Callback[1];
                MessageFormat form = new MessageFormat(
                                       rb.getString(
                                       "Kerberos.username.defUsername."));
                Object[] source =  {defUsername};
                callbacks[0] = new NameCallback(form.format(source));
                callbackHandler.handle(callbacks);
                username = ((NameCallback)callbacks[0]).getName();
                if (username == null || username.length() == 0)
                    username = defUsername;
                krb5PrincName.insert(0, username);

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

    private void promptForPass(boolean getPasswdFromSharedState)
        throws LoginException {

        if (getPasswdFromSharedState) {
            // use the password saved by the first module in the stack
            password = (char[])sharedState.get(PWD);
            if (password == null) {
                if (debug) {
                    System.out.println
                        ("Password from shared state is null");
                }
                throw new LoginException
                    ("Password can not be obtained from sharedstate ");
            }
            if (debug) {
                System.out.println
                    ("password is " + new String(password));
            }
            return;
        }
        if (doNotPrompt) {
            throw new LoginException
                ("Unable to obtain password from user\n");
        } else {
            if (callbackHandler == null)
                throw new LoginException("No CallbackHandler "
                                         + "available "
                                         + "to garner authentication "
                                         + "information from the user");
            try {
                Callback[] callbacks = new Callback[1];
                String userName = krb5PrincName.toString();
                MessageFormat form = new MessageFormat(
                                         rb.getString(
                                         "Kerberos.password.for.username."));
                Object[] source = {userName};
                callbacks[0] = new PasswordCallback(
                                                    form.format(source),
                                                    false);
                callbackHandler.handle(callbacks);
                char[] tmpPassword = ((PasswordCallback)
                                      callbacks[0]).getPassword();
                if (tmpPassword == null) {
                    throw new LoginException("No password provided");
                }
                password = new char[tmpPassword.length];
                System.arraycopy(tmpPassword, 0,
                                 password, 0, tmpPassword.length);
                ((PasswordCallback)callbacks[0]).clearPassword();


                // clear tmpPassword
                for (int i = 0; i < tmpPassword.length; i++)
                    tmpPassword[i] = ' ';
                tmpPassword = null;
                if (debug) {
                    System.out.println("\t\t[Krb5LoginModule] " +
                                       "user entered username: " +
                                       krb5PrincName);
                    System.out.println();
                }
            } catch (java.io.IOException ioe) {
                throw new LoginException(ioe.getMessage());
            } catch (UnsupportedCallbackException uce) {
                throw new LoginException(uce.getMessage()
                                         +" not available to garner "
                                         +" authentication information "
                                         + "from the user");
            }
        }
    }

    private void validateConfiguration() throws LoginException {
        if (doNotPrompt && !useTicketCache && !useKeyTab
                && !tryFirstPass && !useFirstPass)
            throw new LoginException
                ("Configuration Error"
                 + " - either doNotPrompt should be "
                 + " false or at least one of useTicketCache, "
                 + " useKeyTab, tryFirstPass and useFirstPass"
                 + " should be true");
        if (ticketCacheName != null && !useTicketCache)
            throw new LoginException
                ("Configuration Error "
                 + " - useTicketCache should be set "
                 + "to true to use the ticket cache"
                 + ticketCacheName);
        if (keyTabName != null & !useKeyTab)
            throw new LoginException
                ("Configuration Error - useKeyTab should be set to true "
                 + "to use the keytab" + keyTabName);
        if (storeKey && doNotPrompt && !useKeyTab
                && !tryFirstPass && !useFirstPass)
            throw new LoginException
                ("Configuration Error - either doNotPrompt should be set to "
                 + " false or at least one of tryFirstPass, useFirstPass "
                 + "or useKeyTab must be set to true for storeKey option");
        if (renewTGT && !useTicketCache)
            throw new LoginException
                ("Configuration Error"
                 + " - either useTicketCache should be "
                 + " true or renewTGT should be false");
    }

    private static boolean isCurrent(Credentials creds)
    {
        Date endTime = creds.getEndTime();
        if (endTime != null) {
            return (System.currentTimeMillis() <= endTime.getTime());
        }
        return true;
    }

    private static boolean isOld(Credentials creds)
    {
        Date endTime = creds.getEndTime();
        if (endTime != null) {
            Date authTime = creds.getAuthTime();
            long now = System.currentTimeMillis();
            if (authTime != null) {
                // pass the mid between auth and end
                return now - authTime.getTime() > endTime.getTime() - now;
            } else {
                // will expire in less than 2 hours
                return now <= endTime.getTime() - 1000*3600*2L;
            }
        }
        return false;
    }

    private Credentials renewCredentials(Credentials creds)
    {
        Credentials lcreds;
        try {
            if (!creds.isRenewable())
                throw new RefreshFailedException("This ticket" +
                                " is not renewable");
            if (creds.getRenewTill() == null) {
                // Renewable ticket without renew-till. Illegal and ignored.
                return creds;
            }
            if (System.currentTimeMillis() > cred.getRenewTill().getTime())
                throw new RefreshFailedException("This ticket is past "
                                             + "its last renewal time.");
            lcreds = creds.renew();
            if (debug)
                System.out.println("Renewed Kerberos Ticket");
        } catch (Exception e) {
            lcreds = null;
            if (debug)
                System.out.println("Ticket could not be renewed : "
                                + e.getMessage());
        }
        return lcreds;
    }

    
 This method is called if the LoginContext's
overall authentication succeeded
(the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL
LoginModules succeeded).
 If this LoginModule's own authentication attempt
succeeded (checked by retrieving the private state saved by the
login method), then this method associates a
Krb5Principal
with the Subject located in the
LoginModule. It adds Kerberos Credentials to the
 the Subject's private credentials set. If this LoginModule's own
authentication attempted failed, then this method removes
any state that was originally saved.

Throws:
LoginException – if the commit fails.
Returns:
true if this LoginModule's own login and commit
         attempts succeeded, or false otherwise./**
     * <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>Krb5Principal</code>
     * with the <code>Subject</code> located in the
     * <code>LoginModule</code>. It adds Kerberos Credentials to the
     *  the Subject's private credentials set. 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 {

        /*
         * Let us add the Krb5 Creds to the Subject's
         * private credentials. The credentials are of type
         * KerberosKey or KerberosTicket
         */
        if (succeeded == false) {
            return false;
        } else {

            if (isInitiator && (cred == null)) {
                succeeded = false;
                throw new LoginException("Null Client Credential");
            }

            if (subject.isReadOnly()) {
                cleanKerberosCred();
                throw new LoginException("Subject is Readonly");
            }

            /*
             * Add the Principal (authenticated identity)
             * to the Subject's principal set and
             * add the credentials (TGT or Service key) to the
             * Subject's private credentials
             */

            Set<Object> privCredSet =  subject.getPrivateCredentials();
            Set<java.security.Principal> princSet  = subject.getPrincipals();
            kerbClientPrinc = new KerberosPrincipal(principal.getName());

            // create Kerberos Ticket
            if (isInitiator) {
                kerbTicket = Krb5Util.credsToTicket(cred);
            }

            if (storeKey && encKeys != null) {
                if (encKeys.length == 0) {
                    succeeded = false;
                    throw new LoginException("Null Server Key ");
                }

                kerbKeys = new KerberosKey[encKeys.length];
                for (int i = 0; i < encKeys.length; i ++) {
                    Integer temp = encKeys[i].getKeyVersionNumber();
                    kerbKeys[i] = new KerberosKey(kerbClientPrinc,
                                          encKeys[i].getBytes(),
                                          encKeys[i].getEType(),
                                          (temp == null?
                                          0: temp.intValue()));
                }

            }
            // Let us add the kerbClientPrinc,kerbTicket and KeyTab/KerbKey (if
            // storeKey is true)
            if (!princSet.contains(kerbClientPrinc)) {
                princSet.add(kerbClientPrinc);
            }

            // add the TGT
            if (kerbTicket != null) {
                if (!privCredSet.contains(kerbTicket))
                    privCredSet.add(kerbTicket);
            }

            if (storeKey) {
                if (encKeys == null) {
                    if (ktab != null) {
                        if (!privCredSet.contains(ktab)) {
                            privCredSet.add(ktab);
                        }
                    } else {
                        succeeded = false;
                        throw new LoginException("No key to store");
                    }
                } else {
                    for (int i = 0; i < kerbKeys.length; i ++) {
                        if (!privCredSet.contains(kerbKeys[i])) {
                            privCredSet.add(kerbKeys[i]);
                        }
                        encKeys[i].destroy();
                        encKeys[i] = null;
                        if (debug) {
                            System.out.println("Added server's key"
                                            + kerbKeys[i]);
                            System.out.println("\t\t[Krb5LoginModule] " +
                                           "added Krb5Principal  " +
                                           kerbClientPrinc.toString()
                                           + " to Subject");
                        }
                    }
                }
            }
        }
        commitSucceeded = true;
        if (debug)
            System.out.println("Commit Succeeded \n");
        return true;
    }

    
 This method is called if the LoginContext's
overall authentication failed.
(the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL
LoginModules did not succeed).
 If this LoginModule's own authentication attempt
succeeded (checked by retrieving the private state saved by the
login and commit methods),
then this method cleans up any state that was originally saved.

Throws:
LoginException – if the abort fails.
Returns:
false if this LoginModule's own login and/or commit attempts
         failed, and true otherwise./**
     * <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 (succeeded == false) {
            return false;
        } else if (succeeded == true && commitSucceeded == false) {
            // login succeeded but overall authentication failed
            succeeded = false;
            cleanKerberosCred();
        } else {
            // overall authentication succeeded and commit succeeded,
            // but someone else's commit failed
            logout();
        }
        return true;
    }

    
Logout the user.
 This method removes the Krb5Principal
that was added by the commit method.

Throws:
LoginException – if the logout fails.
Returns:
true in all cases since this LoginModule
         should not be ignored./**
     * Logout the user.
     *
     * <p> This method removes the <code>Krb5Principal</code>
     * that was 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 (debug) {
            System.out.println("\t\t[Krb5LoginModule]: " +
                "Entering logout");
        }

        if (subject.isReadOnly()) {
            cleanKerberosCred();
            throw new LoginException("Subject is Readonly");
        }

        subject.getPrincipals().remove(kerbClientPrinc);
           // Let us remove all Kerberos credentials stored in the Subject
        Iterator<Object> it = subject.getPrivateCredentials().iterator();
        while (it.hasNext()) {
            Object o = it.next();
            if (o instanceof KerberosTicket ||
                    o instanceof KerberosKey ||
                    o instanceof KeyTab) {
                it.remove();
            }
        }
        // clean the kerberos ticket and keys
        cleanKerberosCred();

        succeeded = false;
        commitSucceeded = false;
        if (debug) {
            System.out.println("\t\t[Krb5LoginModule]: " +
                               "logged out Subject");
        }
        return true;
    }

    
Clean Kerberos credentials
/**
     * Clean Kerberos credentials
     */
    private void cleanKerberosCred() throws LoginException {
        // Clean the ticket and server key
        try {
            if (kerbTicket != null)
                kerbTicket.destroy();
            if (kerbKeys != null) {
                for (int i = 0; i < kerbKeys.length; i++) {
                    kerbKeys[i].destroy();
                }
            }
        } catch (DestroyFailedException e) {
            throw new LoginException
                ("Destroy Failed on Kerberos Private Credentials");
        }
        kerbTicket = null;
        kerbKeys = null;
        kerbClientPrinc = null;
    }

    
Clean out the state
/**
     * Clean out the state
     */
    private void cleanState() {

        // save input as shared state only if
        // authentication succeeded
        if (succeeded) {
            if (storePass &&
                !sharedState.containsKey(NAME) &&
                !sharedState.containsKey(PWD)) {
                sharedState.put(NAME, username);
                sharedState.put(PWD, password);
            }
        } else {
            // remove temp results for the next try
            encKeys = null;
            ktab = null;
            principal = null;
        }
        username = null;
        password = null;
        if (krb5PrincName != null && krb5PrincName.length() != 0)
            krb5PrincName.delete(0, krb5PrincName.length());
        krb5PrincName = null;
        if (clearPass) {
            sharedState.remove(NAME);
            sharedState.remove(PWD);
        }
    }
}