    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      https://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.codec.digest;
    018
    019import java.nio.charset.StandardCharsets;
    020import java.security.MessageDigest;
    021import java.security.SecureRandom;
    022import java.util.Arrays;
    023import java.util.Objects;
    024import java.util.Random;
    025import java.util.regex.Matcher;
    026import java.util.regex.Pattern;
    027
    028/**
    029 * The libc crypt() "$1$" and Apache "$apr1$" MD5-based hash algorithm.
    030 * <p>
    031 * Based on the public domain ("beer-ware") C implementation from Poul-Henning Kamp which was found at: <a
    032 * href="https://www.freebsd.org/cgi/cvsweb.cgi/src/lib/libcrypt/crypt-md5.c?rev=1.1;content-type=text%2Fplain">
    033 * crypt-md5.c @ freebsd.org</a>
    034 * </p>
    035 * <p>
    036 * Source:
    037 * </p>
    038 * <pre>
    039 * $FreeBSD: src/lib/libcrypt/crypt-md5.c,v 1.1 1999/01/21 13:50:09 brandon Exp $
    040 * </pre>
    041 * <p>
    042 * Conversion to Kotlin and from there to Java in 2012.
    043 * </p>
    044 * <p>
    045 * The C style comments are from the original C code, the ones with "//" from the port.
    046 * </p>
    047 * <p>
    048 * This class is immutable and thread-safe.
    049 * </p>
    050 *
    051 * @since 1.7
    052 */
    053public class Md5Crypt {
    054
    055    /** The Identifier of the Apache variant. */
    056    static final String APR1_PREFIX = "$apr1$";
    057
    058    /** The number of bytes of the final hash. */
    059    private static final int BLOCKSIZE = 16;
    060
    061    /** The Identifier of this crypt() variant. */
    062    static final String MD5_PREFIX = "$1$";
    063
    064    /** The number of rounds of the big loop. */
    065    private static final int ROUNDS = 1000;
    066
    067    /**
    068     * See {@link #apr1Crypt(byte[], String)} for details.
    069     * <p>
    070     * A salt is generated for you using {@link SecureRandom}; your own {@link Random} in
    071     * {@link #apr1Crypt(byte[], Random)}.
    072     * </p>
    073     *
    074     * @param keyBytes plaintext string to hash. Each array element is set to {@code 0} before returning.
    075     * @return the hash value
    076     * @throws IllegalArgumentException when a {@link java.security.NoSuchAlgorithmException} is caught. *
    077     * @see #apr1Crypt(byte[], String)
    078     */
    079    public static String apr1Crypt(final byte[] keyBytes) {
    080        return apr1Crypt(keyBytes, APR1_PREFIX + B64.getRandomSalt(8));
    081    }
    082
    083    /**
    084     * See {@link #apr1Crypt(byte[], String)} for details.
    085     * <p>
    086     * A salt is generated for you using the user provided {@link Random}.
    087     * </p>
    088     *
    089     * @param keyBytes plaintext string to hash. Each array element is set to {@code 0} before returning.
    090     * @param random the instance of {@link Random} to use for generating the salt.
    091     *              Consider using {@link SecureRandom} for more secure salts.
    092     * @return the hash value
    093     * @throws IllegalArgumentException when a {@link java.security.NoSuchAlgorithmException} is caught. *
    094     * @see #apr1Crypt(byte[], String)
    095     * @since 1.12
    096     */
    097    public static String apr1Crypt(final byte[] keyBytes, final Random random) {
    098        return apr1Crypt(keyBytes, APR1_PREFIX + B64.getRandomSalt(8, random));
    099    }
    100
    101    /**
    102     * See {@link #apr1Crypt(String, String)} for details.
    103     * <p>
    104     * A salt is generated for you using {@link SecureRandom}
    105     * </p>
    106     *
    107     * @param keyBytes
    108     *            plaintext string to hash. Each array element is set to {@code 0} before returning.
    109     * @param salt
    110     *            An APR1 salt. The salt may be null, in which case a salt is generated for you using
    111     *            {@link SecureRandom}
    112     * @return the hash value
    113     * @throws IllegalArgumentException
    114     *             if the salt does not match the allowed pattern
    115     * @throws IllegalArgumentException
    116     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
    117     */
    118    public static String apr1Crypt(final byte[] keyBytes, String salt) {
    119        // to make the md5Crypt regex happy
    120        if (salt != null && !salt.startsWith(APR1_PREFIX)) {
    121            salt = APR1_PREFIX + salt;
    122        }
    123        return md5Crypt(keyBytes, salt, APR1_PREFIX);
    124    }
    125
    126    /**
    127     * See {@link #apr1Crypt(String, String)} for details.
    128     * <p>
    129     * A salt is generated for you using {@link SecureRandom}.
    130     * </p>
    131     *
    132     * @param keyBytes
    133     *            plaintext string to hash. Each array element is set to {@code 0} before returning.
    134     * @return the hash value
    135     * @throws IllegalArgumentException
    136     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
    137     * @see #apr1Crypt(byte[], String)
    138     */
    139    public static String apr1Crypt(final String keyBytes) {
    140        return apr1Crypt(keyBytes.getBytes(StandardCharsets.UTF_8));
    141    }
    142
    143    /**
    144     * Generates an Apache htpasswd compatible "$apr1$" MD5 based hash value.
    145     * <p>
    146     * The algorithm is identical to the crypt(3) "$1$" one but produces different outputs due to the different salt
    147     * prefix.
    148     * </p>
    149     *
    150     * @param keyBytes
    151     *            plaintext string to hash. Each array element is set to {@code 0} before returning.
    152     * @param salt
    153     *            salt string including the prefix and optionally garbage at the end. The salt may be null, in which
    154     *            case a salt is generated for you using {@link SecureRandom}.
    155     * @return the hash value
    156     * @throws IllegalArgumentException
    157     *             if the salt does not match the allowed pattern
    158     * @throws IllegalArgumentException
    159     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
    160     */
    161    public static String apr1Crypt(final String keyBytes, final String salt) {
    162        return apr1Crypt(keyBytes.getBytes(StandardCharsets.UTF_8), salt);
    163    }
    164
    165    /**
    166     * Generates a libc6 crypt() compatible "$1$" hash value.
    167     * <p>
    168     * See {@link #md5Crypt(byte[], String)} for details.
    169     * </p>
    170     * <p>
    171     * A salt is generated for you using {@link SecureRandom}.
    172     * </p>
    173     * @param keyBytes
    174     *            plaintext string to hash. Each array element is set to {@code 0} before returning.
    175     * @return the hash value
    176     * @throws IllegalArgumentException
    177     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
    178     * @see #md5Crypt(byte[], String)
    179     */
    180    public static String md5Crypt(final byte[] keyBytes) {
    181        return md5Crypt(keyBytes, MD5_PREFIX + B64.getRandomSalt(8));
    182    }
    183
    184    /**
    185     * Generates a libc6 crypt() compatible "$1$" hash value.
    186     * <p>
    187     * See {@link #md5Crypt(byte[], String)} for details.
    188     * </p>
    189     * <p>
    190     * A salt is generated for you using the instance of {@link Random} you supply.
    191     * </p>
    192     * @param keyBytes
    193     *            plaintext string to hash. Each array element is set to {@code 0} before returning.
    194     * @param random
    195     *            the instance of {@link Random} to use for generating the salt.
    196     *            Consider using {@link SecureRandom} for more secure salts.
    197     * @return the hash value
    198     * @throws IllegalArgumentException
    199     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
    200     * @see #md5Crypt(byte[], String)
    201     * @since 1.12
    202     */
    203    public static String md5Crypt(final byte[] keyBytes, final Random random) {
    204        return md5Crypt(keyBytes, MD5_PREFIX + B64.getRandomSalt(8, random));
    205    }
    206
    207    /**
    208     * Generates a libc crypt() compatible "$1$" MD5 based hash value.
    209     * <p>
    210     * See {@link Crypt#crypt(String, String)} for details. We use {@link SecureRandom} for seed generation by
    211     * default.
    212     * </p>
    213     *
    214     * @param keyBytes
    215     *            plaintext string to hash. Each array element is set to {@code 0} before returning.
    216     * @param salt
    217     *            salt string including the prefix and optionally garbage at the end. The salt may be null, in which
    218     *            case a salt is generated for you using {@link SecureRandom}.
    219     * @return the hash value
    220     * @throws IllegalArgumentException
    221     *             if the salt does not match the allowed pattern
    222     * @throws IllegalArgumentException
    223     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
    224     */
    225    public static String md5Crypt(final byte[] keyBytes, final String salt) {
    226        return md5Crypt(keyBytes, salt, MD5_PREFIX);
    227    }
    228
    229    /**
    230     * Generates a libc6 crypt() "$1$" or Apache htpasswd "$apr1$" hash value.
    231     * <p>
    232     * See {@link Crypt#crypt(String, String)} or {@link #apr1Crypt(String, String)} for details. We use
    233     * {@link SecureRandom by default}.
    234     * </p>
    235     *
    236     * @param keyBytes
    237     *            plaintext string to hash. Each array element is set to {@code 0} before returning.
    238     * @param salt
    239     *            real salt value without prefix or "rounds=". The salt may be null, in which case a salt
    240     *            is generated for you using {@link SecureRandom}.
    241     * @param prefix
    242     *            The salt prefix {@value #APR1_PREFIX}, {@value #MD5_PREFIX}.
    243     * @return the hash value
    244     * @throws IllegalArgumentException
    245     *             if the salt does not match the allowed pattern
    246     * @throws IllegalArgumentException
    247     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
    248     */
    249    public static String md5Crypt(final byte[] keyBytes, final String salt, final String prefix) {
    250        return md5Crypt(keyBytes, salt, prefix, new SecureRandom());
    251    }
    252
    253    /**
    254     * Generates a libc6 crypt() "$1$" or Apache htpasswd "$apr1$" hash value.
    255     * <p>
    256     * See {@link Crypt#crypt(String, String)} or {@link #apr1Crypt(String, String)} for details.
    257     * </p>
    258     *
    259     * @param keyBytes
    260     *            plaintext string to hash. Each array element is set to {@code 0} before returning.
    261     * @param salt
    262     *            real salt value without prefix or "rounds=". The salt may be null, in which case a salt
    263     *            is generated for you using {@link SecureRandom}.
    264     * @param prefix
    265     *            The salt prefix {@value #APR1_PREFIX}, {@value #MD5_PREFIX}.
    266     * @param random
    267     *            the instance of {@link Random} to use for generating the salt.
    268     *            Consider using {@link SecureRandom} for more secure salts.
    269     * @return the hash value
    270     * @throws IllegalArgumentException
    271     *             if the salt or prefix does not match the allowed pattern
    272     * @throws IllegalArgumentException
    273     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
    274     * @since 1.12
    275     */
    276    public static String md5Crypt(final byte[] keyBytes, final String salt, final String prefix, final Random random) {
    277        final int keyLen = keyBytes.length;
    278
    279        // Extract the real salt from the given string which can be a complete hash string.
    280        final String saltString;
    281        if (salt == null) {
    282            saltString = B64.getRandomSalt(8, random);
    283        } else {
    284            Objects.requireNonNull(prefix, "prefix");
    285            if (prefix.length() < 3) {
    286                throw new IllegalArgumentException("Invalid prefix value: " + prefix);
    287            }
    288            if (prefix.charAt(0) != '$' && prefix.charAt(prefix.length() - 1) != '$') {
    289                throw new IllegalArgumentException("Invalid prefix value: " + prefix);
    290            }
    291            final Pattern p = Pattern.compile("^" + prefix.replace("$", "\\$") + "([\\.\\/a-zA-Z0-9]{1,8}).*");
    292            final Matcher m = p.matcher(salt);
    293            if (!m.find()) {
    294                throw new IllegalArgumentException("Invalid salt value: " + salt);
    295            }
    296            saltString = m.group(1);
    297        }
    298        final byte[] saltBytes = saltString.getBytes(StandardCharsets.UTF_8);
    299
    300        final MessageDigest ctx = DigestUtils.getMd5Digest();
    301
    302        /*
    303         * The password first, since that is what is most unknown
    304         */
    305        ctx.update(keyBytes);
    306
    307        /*
    308         * Then our magic string
    309         */
    310        ctx.update(prefix.getBytes(StandardCharsets.UTF_8));
    311
    312        /*
    313         * Then the raw salt
    314         */
    315        ctx.update(saltBytes);
    316
    317        /*
    318         * Then just as many characters of the MD5(pw,salt,pw)
    319         */
    320        MessageDigest ctx1 = DigestUtils.getMd5Digest();
    321        ctx1.update(keyBytes);
    322        ctx1.update(saltBytes);
    323        ctx1.update(keyBytes);
    324        byte[] finalb = ctx1.digest();
    325        int ii = keyLen;
    326        while (ii > 0) {
    327            ctx.update(finalb, 0, Math.min(ii, 16));
    328            ii -= 16;
    329        }
    330
    331        /*
    332         * Don't leave anything around in JVM they could use.
    333         */
    334        Arrays.fill(finalb, (byte) 0);
    335
    336        /*
    337         * Then something really weird...
    338         */
    339        ii = keyLen;
    340        final int j = 0;
    341        while (ii > 0) {
    342            if ((ii & 1) == 1) {
    343                ctx.update(finalb[j]);
    344            } else {
    345                ctx.update(keyBytes[j]);
    346            }
    347            ii >>= 1;
    348        }
    349
    350        /*
    351         * Now make the output string
    352         */
    353        final StringBuilder passwd = new StringBuilder(prefix + saltString + "$");
    354        finalb = ctx.digest();
    355
    356        /*
    357         * and now, just to make sure things don't run too fast On a 60 Mhz Pentium this takes 34 milliseconds, so you
    358         * would need 30 seconds to build a 1000 entry dictionary...
    359         */
    360        for (int i = 0; i < ROUNDS; i++) {
    361            ctx1 = DigestUtils.getMd5Digest();
    362            if ((i & 1) != 0) {
    363                ctx1.update(keyBytes);
    364            } else {
    365                ctx1.update(finalb, 0, BLOCKSIZE);
    366            }
    367
    368            if (i % 3 != 0) {
    369                ctx1.update(saltBytes);
    370            }
    371
    372            if (i % 7 != 0) {
    373                ctx1.update(keyBytes);
    374            }
    375
    376            if ((i & 1) != 0) {
    377                ctx1.update(finalb, 0, BLOCKSIZE);
    378            } else {
    379                ctx1.update(keyBytes);
    380            }
    381            finalb = ctx1.digest();
    382        }
    383
    384        // The following was nearly identical to the Sha2Crypt code.
    385        // Again, the buflen is not really needed.
    386        // int buflen = MD5_PREFIX.length() - 1 + salt_string.length() + 1 + BLOCKSIZE + 1;
    387        B64.b64from24bit(finalb[0], finalb[6], finalb[12], 4, passwd);
    388        B64.b64from24bit(finalb[1], finalb[7], finalb[13], 4, passwd);
    389        B64.b64from24bit(finalb[2], finalb[8], finalb[14], 4, passwd);
    390        B64.b64from24bit(finalb[3], finalb[9], finalb[15], 4, passwd);
    391        B64.b64from24bit(finalb[4], finalb[10], finalb[5], 4, passwd);
    392        B64.b64from24bit((byte) 0, (byte) 0, finalb[11], 2, passwd);
    393
    394        /*
    395         * Don't leave anything around in JVM they could use.
    396         */
    397        // Is there a better way to do this with the JVM?
    398        ctx.reset();
    399        ctx1.reset();
    400        Arrays.fill(keyBytes, (byte) 0);
    401        Arrays.fill(saltBytes, (byte) 0);
    402        Arrays.fill(finalb, (byte) 0);
    403
    404        return passwd.toString();
    405    }
    406
    407    /**
    408     * TODO Make private in 2.0.
    409     *
    410     * @deprecated TODO Make private in 2.0.
    411     */
    412    @Deprecated
    413    public Md5Crypt() {
    414        // empty
    415    }
    416}