/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

/*
 * Unix SMB/Netbios implementation.
 * Version 1.9.
 *
 * a partial implementation of DES designed for use in the
 * SMB authentication protocol
 *
 * Copyright (C) Andrew Tridgell 1997
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "squid.h"

/* NOTES:
 *
 * This code makes no attempt to be fast! In fact, it is a very
 * slow implementation
 *
 * This code is NOT a complete DES implementation. It implements only
 * the minimum necessary for SMB authentication, as used by all SMB
 * products (including every copy of Microsoft Windows95 ever sold)
 *
 * In particular, it can only do a unchained forward DES pass. This
 * means it is not possible to use this code for encryption/decryption
 * of data, instead it is only useful as a "hash" algorithm.
 *
 * There is no entry point into this code that allows normal DES operation.
 *
 * I believe this means that this code does not come under ITAR
 * regulations but this is NOT a legal opinion. If you are concerned
 * about the applicability of ITAR regulations to this code then you
 * should confirm it for yourself (and maybe let me know if you come
 * up with a different answer to the one above)
 */

#include "smbdes.h"

static int perm1[56] = {57, 49, 41, 33, 25, 17, 9,
                        1, 58, 50, 42, 34, 26, 18,
                        10, 2, 59, 51, 43, 35, 27,
                        19, 11, 3, 60, 52, 44, 36,
                        63, 55, 47, 39, 31, 23, 15,
                        7, 62, 54, 46, 38, 30, 22,
                        14, 6, 61, 53, 45, 37, 29,
                        21, 13, 5, 28, 20, 12, 4
                       };

static int perm2[48] = {14, 17, 11, 24, 1, 5,
                        3, 28, 15, 6, 21, 10,
                        23, 19, 12, 4, 26, 8,
                        16, 7, 27, 20, 13, 2,
                        41, 52, 31, 37, 47, 55,
                        30, 40, 51, 45, 33, 48,
                        44, 49, 39, 56, 34, 53,
                        46, 42, 50, 36, 29, 32
                       };

static int perm3[64] = {58, 50, 42, 34, 26, 18, 10, 2,
                        60, 52, 44, 36, 28, 20, 12, 4,
                        62, 54, 46, 38, 30, 22, 14, 6,
                        64, 56, 48, 40, 32, 24, 16, 8,
                        57, 49, 41, 33, 25, 17, 9, 1,
                        59, 51, 43, 35, 27, 19, 11, 3,
                        61, 53, 45, 37, 29, 21, 13, 5,
                        63, 55, 47, 39, 31, 23, 15, 7
                       };

static int perm4[48] = {32, 1, 2, 3, 4, 5,
                        4, 5, 6, 7, 8, 9,
                        8, 9, 10, 11, 12, 13,
                        12, 13, 14, 15, 16, 17,
                        16, 17, 18, 19, 20, 21,
                        20, 21, 22, 23, 24, 25,
                        24, 25, 26, 27, 28, 29,
                        28, 29, 30, 31, 32, 1
                       };

static int perm5[32] = {16, 7, 20, 21,
                        29, 12, 28, 17,
                        1, 15, 23, 26,
                        5, 18, 31, 10,
                        2, 8, 24, 14,
                        32, 27, 3, 9,
                        19, 13, 30, 6,
                        22, 11, 4, 25
                       };

static int perm6[64] = {40, 8, 48, 16, 56, 24, 64, 32,
                        39, 7, 47, 15, 55, 23, 63, 31,
                        38, 6, 46, 14, 54, 22, 62, 30,
                        37, 5, 45, 13, 53, 21, 61, 29,
                        36, 4, 44, 12, 52, 20, 60, 28,
                        35, 3, 43, 11, 51, 19, 59, 27,
                        34, 2, 42, 10, 50, 18, 58, 26,
                        33, 1, 41, 9, 49, 17, 57, 25
                       };

static int sc[16] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};

static int sbox[8][4][16] = {
    {
        {14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7},
        {0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8},
        {4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0},
        {15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}
    },

    {
        {15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10},
        {3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5},
        {0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15},
        {13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}
    },

    {
        {10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8},
        {13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1},
        {13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7},
        {1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}
    },

    {
        {7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15},
        {13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9},
        {10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4},
        {3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}
    },

    {
        {2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9},
        {14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6},
        {4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14},
        {11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}
    },

    {
        {12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11},
        {10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8},
        {9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6},
        {4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}
    },

    {
        {4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1},
        {13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6},
        {1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2},
        {6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}
    },

    {
        {13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7},
        {1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2},
        {7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8},
        {2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11}
    }
};

static void
permute(char *out, char *in, int *p, int n)
{
    int i;
    for (i = 0; i < n; i++)
        out[i] = in[p[i] - 1];
}

static void
lshift(char *d, int count, int n)
{
    char out[64];
    int i;
    for (i = 0; i < n; i++)
        out[i] = d[(i + count) % n];
    for (i = 0; i < n; i++)
        d[i] = out[i];
}

static void
concat(char *out, char *in1, char *in2, int l1, int l2)
{
    while (l1--)
        *out++ = *in1++;
    while (l2--)
        *out++ = *in2++;
}

static void
xor(char *out, char *in1, char *in2, int n)
{
    int i;
    for (i = 0; i < n; i++)
        out[i] = in1[i] ^ in2[i];
}

static void
dohash(char *out, char *in, char *key)
{
    int i, j, k;
    char pk1[56];
    char c[28];
    char d[28];
    char cd[56];
    char ki[16][48];
    char pd1[64];
    char l[32], r[32];
    char rl[64];

    permute(pk1, key, perm1, 56);

    for (i = 0; i < 28; i++)
        c[i] = pk1[i];
    for (i = 0; i < 28; i++)
        d[i] = pk1[i + 28];

    for (i = 0; i < 16; i++) {
        lshift(c, sc[i], 28);
        lshift(d, sc[i], 28);

        concat(cd, c, d, 28, 28);
        permute(ki[i], cd, perm2, 48);
    }

    permute(pd1, in, perm3, 64);

    for (j = 0; j < 32; j++) {
        l[j] = pd1[j];
        r[j] = pd1[j + 32];
    }

    for (i = 0; i < 16; i++) {
        char er[48];
        char erk[48];
        char b[8][6];
        char cb[32];
        char pcb[32];
        char r2[32];

        permute(er, r, perm4, 48);

        xor(erk, er, ki[i], 48);

        for (j = 0; j < 8; j++)
            for (k = 0; k < 6; k++)
                b[j][k] = erk[j * 6 + k];

        for (j = 0; j < 8; j++) {
            int m, n;
            m = (b[j][0] << 1) | b[j][5];

            n = (b[j][1] << 3) | (b[j][2] << 2) | (b[j][3] << 1) | b[j][4];

            for (k = 0; k < 4; k++)
                b[j][k] = (sbox[j][m][n] & (1 << (3 - k))) ? 1 : 0;
        }

        for (j = 0; j < 8; j++)
            for (k = 0; k < 4; k++)
                cb[j * 4 + k] = b[j][k];
        permute(pcb, cb, perm5, 32);

        xor(r2, l, pcb, 32);

        for (j = 0; j < 32; j++)
            l[j] = r[j];

        for (j = 0; j < 32; j++)
            r[j] = r2[j];
    }

    concat(rl, r, l, 32, 32);

    permute(out, rl, perm6, 64);
}

static void
str_to_key(unsigned char *str, unsigned char *key)
{
    int i;

    key[0] = str[0] >> 1;
    key[1] = ((str[0] & 0x01) << 6) | (str[1] >> 2);
    key[2] = ((str[1] & 0x03) << 5) | (str[2] >> 3);
    key[3] = ((str[2] & 0x07) << 4) | (str[3] >> 4);
    key[4] = ((str[3] & 0x0F) << 3) | (str[4] >> 5);
    key[5] = ((str[4] & 0x1F) << 2) | (str[5] >> 6);
    key[6] = ((str[5] & 0x3F) << 1) | (str[6] >> 7);
    key[7] = str[6] & 0x7F;
    for (i = 0; i < 8; i++) {
        key[i] = (key[i] << 1);
    }
}

static void
smbhash(unsigned char *out, unsigned char *in, unsigned char *key)
{
    int i;
    char outb[64];
    char inb[64];
    char keyb[64];
    unsigned char key2[8];

    str_to_key(key, key2);

    for (i = 0; i < 64; i++) {
        inb[i] = (in[i / 8] & (1 << (7 - (i % 8)))) ? 1 : 0;
        keyb[i] = (key2[i / 8] & (1 << (7 - (i % 8)))) ? 1 : 0;
        outb[i] = 0;
    }

    dohash(outb, inb, keyb);

    for (i = 0; i < 8; i++) {
        out[i] = 0;
    }

    for (i = 0; i < 64; i++) {
        if (outb[i])
            out[i / 8] |= (1 << (7 - (i % 8)));
    }
}

void
E_P16(unsigned char *p14, unsigned char *p16)
{
    unsigned char sp8[8] = {0x4b, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25};
    smbhash(p16, sp8, p14);
    smbhash(p16 + 8, sp8, p14 + 7);
}

void
E_P24(unsigned char *p21, unsigned char *c8, unsigned char *p24)
{
    smbhash(p24, c8, p21);
    smbhash(p24 + 8, c8, p21 + 7);
    smbhash(p24 + 16, c8, p21 + 14);
}

void
cred_hash1(unsigned char *out, unsigned char *in, unsigned char *key)
{
    unsigned char buf[8];

    smbhash(buf, in, key);
    smbhash(out, buf, key + 9);
}

void
cred_hash2(unsigned char *out, unsigned char *in, unsigned char *key)
{
    unsigned char buf[8];
    static unsigned char key2[8];

    smbhash(buf, in, key);
    key2[0] = key[7];
    smbhash(out, buf, key2);
}