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	/*
	* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.security.sasl;

	import javax.security.sasl.*;

	/**
	* Implements the PLAIN SASL client mechanism.
	* (<A
	* HREF="http://ftp.isi.edu/in-notes/rfc2595.txt">RFC 2595</A>)
	*
	* @author Rosanna Lee
	*/
	final class PlainClient implements SaslClient {
	private boolean completed = false;
	private byte[] pw;
	private String authorizationID;
	private String authenticationID;
	private static byte SEP = 0; // US-ASCII <NUL>

	/**
	* Creates a SASL mechanism with client credentials that it needs
	* to participate in Plain authentication exchange with the server.
	*
	* @param authorizationID A possibly null string representing the principal
	* for which authorization is being granted; if null, same as
	* authenticationID
	* @param authenticationID A non-null string representing the principal
	* being authenticated. pw is associated with with this principal.
	* @param pw A non-null byte[] containing the password.
	*/
	PlainClient(String authorizationID, String authenticationID, byte[] pw)
	throws SaslException {
	if (authenticationID == null \|\| pw == null) {
	throw new SaslException(
	"PLAIN: authorization ID and password must be specified");
	}

	this.authorizationID = authorizationID;
	this.authenticationID = authenticationID;
	this.pw = pw; // caller should have already cloned
	}

	/**
	* Retrieves this mechanism's name for to initiate the PLAIN protocol
	* exchange.
	*
	* @return The string "PLAIN".
	*/
	public String getMechanismName() {
	return "PLAIN";
	}

	public boolean hasInitialResponse() {
	return true;
	}

	public void dispose() throws SaslException {
	clearPassword();
	}

	/**
	* Retrieves the initial response for the SASL command, which for
	* PLAIN is the concatenation of authorization ID, authentication ID
	* and password, with each component separated by the US-ASCII <NUL> byte.
	*
	* @param challengeData Ignored
	* @return A non-null byte array containing the response to be sent to the server.
	* @throws SaslException If cannot encode ids in UTF-8
	* @throw IllegalStateException if authentication already completed
	*/
	public byte[] evaluateChallenge(byte[] challengeData) throws SaslException {
	if (completed) {
	throw new IllegalStateException(
	"PLAIN authentication already completed");
	}
	completed = true;

	try {
	byte[] authz = (authorizationID != null)?
	authorizationID.getBytes("UTF8") :
	null;
	byte[] auth = authenticationID.getBytes("UTF8");

	byte[] answer = new byte[pw.length + auth.length + 2 +
	(authz == null ? 0 : authz.length)];

	int pos = 0;
	if (authz != null) {
	System.arraycopy(authz, 0, answer, 0, authz.length);
	pos = authz.length;
	}
	answer[pos++] = SEP;
	System.arraycopy(auth, 0, answer, pos, auth.length);

	pos += auth.length;
	answer[pos++] = SEP;

	System.arraycopy(pw, 0, answer, pos, pw.length);

	clearPassword();
	return answer;
	} catch (java.io.UnsupportedEncodingException e) {
	throw new SaslException("Cannot get UTF-8 encoding of ids", e);
	}
	}

	/**
	* Determines whether this mechanism has completed.
	* Plain completes after returning one response.
	*
	* @return true if has completed; false otherwise;
	*/
	public boolean isComplete() {
	return completed;
	}

	/**
	* Unwraps the incoming buffer.
	*
	* @throws SaslException Not applicable to this mechanism.
	*/
	public byte[] unwrap(byte[] incoming, int offset, int len)
	throws SaslException {
	if (completed) {
	throw new SaslException(
	"PLAIN supports neither integrity nor privacy");
	} else {
	throw new IllegalStateException("PLAIN authentication not completed");
	}
	}

	/**
	* Wraps the outgoing buffer.
	*
	* @throws SaslException Not applicable to this mechanism.
	*/
	public byte[] wrap(byte[] outgoing, int offset, int len) throws SaslException {
	if (completed) {
	throw new SaslException(
	"PLAIN supports neither integrity nor privacy");
	} else {
	throw new IllegalStateException("PLAIN authentication not completed");
	}
	}

	/**
	* Retrieves the negotiated property.
	* This method can be called only after the authentication exchange has
	* completed (i.e., when {@code isComplete()} returns true); otherwise, a
	* {@code SaslException} is thrown.
	*
	* @return value of property; only QOP is applicable to PLAIN.
	* @exception IllegalStateException if this authentication exchange
	* has not completed
	*/
	public Object getNegotiatedProperty(String propName) {
	if (completed) {
	if (propName.equals(Sasl.QOP)) {
	return "auth";
	} else {
	return null;
	}
	} else {
	throw new IllegalStateException("PLAIN authentication not completed");
	}
	}

	private void clearPassword() {
	if (pw != null) {
	// zero out password
	for (int i = 0; i < pw.length; i++) {
	pw[i] = (byte)0;
	}
	pw = null;
	}
	}

	protected void finalize() {
	clearPassword();
	}
	}

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