LDAP changing user password on Active Directory

I state that I am a complete beginner to LDAP.
I have to let a user change its own password through an Android device. User has NOT administrative privileges.
Using the UnboudId LDAP SDK for Java I'm able to bind to server and get the user entry using this code:

final SocketFactory _socket_factory;
final SSLUtil _ssl_util = new SSLUtil(new TrustAllTrustManager());
try {               
  _socket_factory = _ssl_util.createSSLSocketFactory();             
}
catch (Exception e) {
  Log.e(LOG_TAG, "*** Unable to initialize ssl", e);
}

LDAPConnectionOptions _ldap_connection_options = new LDAPConnectionOptions();
_ldap_connection_options.setAutoReconnect(true);
_ldap_connection_options.setConnectTimeoutMillis(30000);
_ldap_connection_options.setFollowReferrals(false);
_ldap_connection_options.setMaxMessageSize(1024*1024);

LDAPConnection _ldap_connection = new LDAPConnection(_socket_factory, _ldap_connection_options, [host ip], 636, [username], [password]);

Filter _filter = Filter.create("(userPrincipalName=" + [username] + ")");
SearchRequest _search_request = new SearchRequest([base DN], SearchScope.SUB, _filter);
_search_request.setSizeLimit(1000);
_search_request.setTimeLimitSeconds(30);            

SearchResult _search_result = _connection.search(_search_request);

This works and I get 1 entry and all the relative attributes. Now my task is to change the password [password] with a new [new password].
My attempts:

PasswordModifyExtendedRequest _password_modify_request = new PasswordModifyExtendedRequest([found entry DN], [password], [new password]);
PasswordModifyExtendedResult _password_modify_result = (PasswordModifyExtendedResult)_ldap_connection.processExtendedOperation(_password_modify_request);

This doesn't work due to LDAPException

LDAPException(resultCode=2 (protocol error), errorMessage='0000203D: LdapErr: DSID-0C090C7D, comment: Unknown extended request OID, data 0, vece��', diagnosticMessage='0000203D: LdapErr: DSID-0C090C7D, comment: Unknown extended request OID, data 0, vece��')

Then I've tryed

final Modification _replace_modification = new Modification(ModificationType.REPLACE, "unicodePwd", _get_quoted_string_bytes([new password]));
LDAPResult _result = _connection.modify([found entry DN], _replace_modification);

This doesn't work due to LDAPException

LDAPException(resultCode=50 (insufficient access rights), errorMessage='00000005: SecErr: DSID-031A0F44, problem 4003 (INSUFF_ACCESS_RIGHTS), data 0)

Finally I've tryed

final Modification _delete_old_modification = new Modification(ModificationType.DELETE, "unicodePwd", _get_quoted_string_bytes([password]));
final Modification _add_new_modification = new Modification(ModificationType.ADD, "unicodePwd", _get_quoted_string_bytes([new password]));
final ArrayList<Modification> _modifications = new ArrayList<Modification>();
_modifications.add(_delete_old_modification);
_modifications.add(_add_new_modification);
LDAPResult _result = _connection.modify([found entry DN], _modifications);

This doesn't work due to LDAPException

LDAPException(resultCode=19 (constraint violation), errorMessage='00000005: AtrErr: DSID-03190F00, #1:0: 00000005: DSID-03190F00, problem 1005 (CONSTRAINT_ATT_TYPE), data 0, Att 9005a (unicodePwd)��', diagnosticMessage='00000005: AtrErr: DSID-03190F00, #1: 0: 00000005: DSID-03190F00, problem 1005 (CONSTRAINT_ATT_TYPE), data 0, Att 9005a (unicodePwd) ��')

And now i have no more ideas... Any help will be appreciated, thanks in advance

回答1:

final Modification _delete_old_modification = new Modification(ModificationType.DELETE, "unicodePwd", ('"' + oldPassword + '"').getBytes("UTF-16LE"));
final Modification _add_new_modification = new Modification(ModificationType.ADD, "unicodePwd", ('"' + newPassword + '"').getBytes("UTF-16LE"));

Did the trick.

回答2:

Finally, I was able to resolve CONSTRAINT_ATT_TYPE issue in password change. I had set minimum password age as 4 days, so AD wasn’t allowing me to update the password. AD throws generic error CONSTRAINT_ATT_TYPE for all such violations. After setting minimum password age as 0 (None), everything works fine. AD password history also gets updated.

Refer: http://www.javaxt.com/Tutorials/Windows/How_to_Authenticate_Users_with_Active_Directory