/*
   Unix SMB/Netbios implementation.
   Version 1.9.

   a partial implementation of DES designed for use in the 
   SMB authentication protocol

   Copyright (C) Andrew Tridgell 1998

   Copyright (C) 2011-2021
   Free Software Foundation, Inc.

   This file is part of the Midnight Commander.

   The Midnight Commander 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 3 of the License,
   or (at your option) any later version.

   The Midnight Commander 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, see <http://www.gnu.org/licenses/>.
 */

#include "includes.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)
 */

#undef	uchar
#define uchar const unsigned char

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

static uchar 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, uchar * 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 forw)
{
    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[forw ? i : 15 - 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 forw)
{
    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, forw);

    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, 1);
    smbhash (p16 + 8, sp8, p14 + 7, 1);
}

void
E_P24 (unsigned char *p21, unsigned char *c8, unsigned char *p24)
{
    smbhash (p24, c8, p21, 1);
    smbhash (p24 + 8, c8, p21 + 7, 1);
    smbhash (p24 + 16, c8, p21 + 14, 1);
}

#if 0
void
D_P16 (unsigned char *p14, unsigned char *in, unsigned char *out)
{
    smbhash (out, in, p14, 0);
    smbhash (out + 8, in + 8, p14 + 7, 0);
}

void
E_old_pw_hash (unsigned char *p14, unsigned char *in, unsigned char *out)
{
    smbhash (out, in, p14, 1);
    smbhash (out + 8, in + 8, p14 + 7, 1);
}

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

    smbhash (buf, in, key, 1);
    smbhash (out, buf, key + 9, 1);
}

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, 1);
    key2[0] = key[7];
    smbhash (out, buf, key2, 1);
}

void
cred_hash3 (unsigned char *out, unsigned char *in, unsigned char *key, int forw)
{
    static unsigned char key2[8];

    smbhash (out, in, key, forw);
    key2[0] = key[7];
    smbhash (out + 8, in + 8, key2, forw);
}

void
SamOEMhash (unsigned char *data, unsigned char *key, int val)
{
    unsigned char s_box[256];
    unsigned char index_i = 0;
    unsigned char index_j = 0;
    unsigned char j = 0;
    int ind;

    for (ind = 0; ind < 256; ind++)
    {
        s_box[ind] = (unsigned char) ind;
    }

    for (ind = 0; ind < 256; ind++)
    {
        unsigned char tc;

        j += (s_box[ind] + key[ind % 16]);

        tc = s_box[ind];
        s_box[ind] = s_box[j];
        s_box[j] = tc;
    }
    for (ind = 0; ind < (val ? 516 : 16); ind++)
    {
        unsigned char tc;
        unsigned char t;

        index_i++;
        index_j += s_box[index_i];

        tc = s_box[index_i];
        s_box[index_i] = s_box[index_j];
        s_box[index_j] = tc;

        t = s_box[index_i] + s_box[index_j];
        data[ind] = data[ind] ^ s_box[t];
    }
}
#endif /* 0 */
