/*

 * Copyright (c) 2010, 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.ntlm;

import java.util.Arrays;

import java.util.Locale;

/**

 * The NTLM server, not multi-thread enabled.<p>

 * Example:

 * <pre>

 * Server server = new Server(null, "REALM") {

 *     public char[] getPassword(String ntdomain, String username) {

 *         switch (username) {

 *             case "dummy": return "t0pSeCr3t".toCharArray();

 *             case "guest": return "".toCharArray();

 *             default: return null;

 *         }

 *     }

 * };

 * // Receive client request as type1

 * byte[] type2 = server.type2(type1, nonce);

 * // Send type2 to client and receive type3

 * verify(type3, nonce);

 * </pre>

 */

public abstract class Server extends NTLM {

    final private String domain;

    final private boolean allVersion;

    /**

     * Creates a Server instance.

     * @param version the NTLM version to use, which can be:

     * <ul>

     * <li>NTLM: Original NTLM v1

     * <li>NTLM2: NTLM v1 with Client Challenge

     * <li>NTLMv2: NTLM v2

     * </ul>

     * If null, all versions will be supported. Please note that unless NTLM2

     * is selected, authentication succeeds if one of LM (or LMv2) or

     * NTLM (or NTLMv2) is verified.

     * @param domain the domain, must not be null

     * @throws NTLMException if {@code domain} is null.

     */

    public Server(String version, String domain) throws NTLMException {

        super(version);

        if (domain == null) {

            throw new NTLMException(NTLMException.PROTOCOL,

                    "domain cannot be null");

        }

        this.allVersion = (version == null);

        this.domain = domain;

        debug("NTLM Server: (t,version) = (%s,%s)\n", domain, version);

    }

    /**

     * Generates the Type 2 message

     * @param type1 the Type1 message received, must not be null

     * @param nonce the random 8-byte array to be used in message generation,

     * must not be null

     * @return the message generated

     * @throws NTLMException if the incoming message is invalid, or

     * {@code nonce} is null.

     */

    public byte[] type2(byte[] type1, byte[] nonce) throws NTLMException {

        if (nonce == null) {

            throw new NTLMException(NTLMException.PROTOCOL,

                    "nonce cannot be null");

        }

        debug("NTLM Server: Type 1 received\n");

        if (type1 != null) debug(type1);

        Writer p = new Writer(2, 32);

        int flags = 0x80205;

        p.writeSecurityBuffer(12, domain, true);

        p.writeInt(20, flags);

        p.writeBytes(24, nonce);

        debug("NTLM Server: Type 2 created\n");

        debug(p.getBytes());

        return p.getBytes();

    }

    /**

     * Verifies the Type3 message received from client and returns

     * various negotiated information.

     * @param type3 the incoming Type3 message from client, must not be null

     * @param nonce the same nonce provided in {@link #type2}, must not be null

     * @throws NTLMException if the incoming message is invalid, or

     * {@code nonce} is null.

     */

    public String[] verify(byte[] type3, byte[] nonce)

            throws NTLMException {

        if (type3 == null || nonce == null) {

            throw new NTLMException(NTLMException.PROTOCOL,

                    "type1 or nonce cannot be null");

        }

        debug("NTLM Server: Type 3 received\n");

        if (type3 != null) debug(type3);

        Reader r = new Reader(type3);

        String username = r.readSecurityBuffer(36, true);

        String hostname = r.readSecurityBuffer(44, true);

        String incomingDomain = r.readSecurityBuffer(28, true);

        /*if (incomingDomain != null && !incomingDomain.equals(domain)) {

            throw new NTLMException(NTLMException.DOMAIN_UNMATCH,

                    "Wrong domain: " + incomingDomain +

                    " vs " + domain); // Needed?

        }*/

        boolean verified = false;

        char[] password = getPassword(domain, username);

        if (password == null) {

            throw new NTLMException(NTLMException.USER_UNKNOWN,

                    "Unknown user");

        }

        byte[] incomingLM = r.readSecurityBuffer(12);

        byte[] incomingNTLM = r.readSecurityBuffer(20);

        if (!verified && (allVersion || v == Version.NTLM)) {

            if (incomingLM.length > 0) {

                byte[] pw1 = getP1(password);

                byte[] lmhash = calcLMHash(pw1);

                byte[] lmresponse = calcResponse (lmhash, nonce);

                if (Arrays.equals(lmresponse, incomingLM)) {

                    verified = true;

                }

            }

            if (incomingNTLM.length > 0) {

                byte[] pw2 = getP2(password);

                byte[] nthash = calcNTHash(pw2);

                byte[] ntresponse = calcResponse (nthash, nonce);

                if (Arrays.equals(ntresponse, incomingNTLM)) {

                    verified = true;

                }

            }

            debug("NTLM Server: verify using NTLM: " + verified  + "\n");

        }

        if (!verified && (allVersion || v == Version.NTLM2)) {

            byte[] pw2 = getP2(password);

            byte[] nthash = calcNTHash(pw2);

            byte[] clientNonce = Arrays.copyOf(incomingLM, 8);

            byte[] ntlmresponse = ntlm2NTLM(nthash, clientNonce, nonce);

            if (Arrays.equals(incomingNTLM, ntlmresponse)) {

                verified = true;

            }

            debug("NTLM Server: verify using NTLM2: " + verified + "\n");

        }

        if (!verified && (allVersion || v == Version.NTLMv2)) {

            byte[] pw2 = getP2(password);

            byte[] nthash = calcNTHash(pw2);

            if (incomingLM.length > 0) {

                byte[] clientNonce = Arrays.copyOfRange(

                        incomingLM, 16, incomingLM.length);

                byte[] lmresponse = calcV2(nthash,

                        username.toUpperCase(Locale.US)+incomingDomain,

                        clientNonce, nonce);

                if (Arrays.equals(lmresponse, incomingLM)) {

                    verified = true;

                }

            }

            if (incomingNTLM.length > 0) {

                byte[] clientBlob = Arrays.copyOfRange(

                        incomingNTLM, 16, incomingNTLM.length);

                byte[] ntlmresponse = calcV2(nthash,

                        username.toUpperCase(Locale.US)+incomingDomain,

                        clientBlob, nonce);

                if (Arrays.equals(ntlmresponse, incomingNTLM)) {

                    verified = true;

                }

            }

            debug("NTLM Server: verify using NTLMv2: " + verified + "\n");

        }

        if (!verified) {

            throw new NTLMException(NTLMException.AUTH_FAILED,

                    "None of LM and NTLM verified");

        }

    }

    /**

     * Retrieves the password for a given user. This method should be

     * overridden in a concrete class.

     * @param domain can be null

     * @param username must not be null

     * @return the password for the user, or null if unknown

     */

    public abstract char[] getPassword(String domain, String username);

}