/*
 * :ts=4
 *
 * Password encryption routines, lifted from the Samba source code,
 * "libsmb/smbencrypt.c", "libsmb/smbdes.c" and "lib/md4.c":
 *
 * Unix SMB/Netbios implementation.
 * Version 1.9.
 *
 * SMB parameters and setup
 *
 * A partial implementation of DES designed for use in the
 * SMB authentication protocol
 *
 * An implementation of MD4 designed for use in the SMB authentication protocol
 *
 * Copyright (C) Andrew Tridgell 1992-1998
 * Modified by Jeremy Allison 1995.
 *
 * 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 "smbfs.h"

/****************************************************************************/

#include <smb/smb.h>

/****************************************************************************/

static void permute (char *out, const char *in, const unsigned char * const p, int n);
static void left_shift (char *d, int count, int n);
static void concat (char *out, const char *in1, const char *in2, int l1, int l2);
static void xor (char *out, const char *in1, const char *in2, int n);
static void dohash (char *out, const char *in, const char *key, int forw);
static void str_to_key (const unsigned char *str, unsigned char *key);
static void smbhash (unsigned char *out, const unsigned char *in, const unsigned char *key, int forw);
static void E_P16 (const unsigned char *p14, unsigned char *p16);
static void E_P24 (const unsigned char *p21, const unsigned char *c8, unsigned char *p24);
static int local_mbstowcs (short *dst, const unsigned char *src, int len);
static void E_md4hash (const unsigned char *passwd, unsigned char *p16);
static void smb_owf_encrypt (const unsigned char *passwd, const unsigned char *c8, unsigned char *p24);
static unsigned long F (unsigned long X, unsigned long Y, unsigned long Z);
static unsigned long G (unsigned long X, unsigned long Y, unsigned long Z);
static unsigned long H (unsigned long X, unsigned long Y, unsigned long Z);
static unsigned long lshift (unsigned long x, int s);
static void mdfour64 (unsigned long *M);
static void copy64 (unsigned long *M, const unsigned char *in);
static void copy4 (unsigned char *out, unsigned long x);
static void mdfour (unsigned char *out, const unsigned char *in, int n);

/****************************************************************************/

/* 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 an 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) */

static const unsigned char 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 const unsigned char 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 const unsigned char 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 const unsigned char 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 const unsigned char 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 const unsigned char 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 const unsigned char sc[16] =
{
	1, 1, 2, 2,
	2, 2, 2, 2,
	1, 2, 2, 2,
	2, 2, 2, 1
};

static const unsigned char 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, const char *in, const unsigned char * const p, int n)
{
	int i;

	for (i = 0; i < n; i++)
		out[i] = in[p[i] - 1];
}

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

	while (l2--)
		(*out++) = (*in2++);
}

static void
xor (char *out, const char *in1, const char *in2, int n)
{
	int i;

	for (i = 0; i < n; i++)
		out[i] = in1[i] ^ in2[i];
}

static void
dohash (char *out, const char *in, const 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++)
	{
		left_shift (c, sc[i], 28);
		left_shift (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 (const 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, const unsigned char *in, const 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)));
	}
}

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

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

static void
E_P24 (const unsigned char *p21, const 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);
}

/****************************************************************************/

/* This implements the X/Open SMB password encryption
   It takes a password, an 8 byte "crypt key" and puts 24 bytes of
   encrypted password into p24 */
void
smb_encrypt (const unsigned char *passwd, const unsigned char *c8, unsigned char *p24)
{
	unsigned char p14[15], p21[21];
	int len;

	memset (p21, '\0', sizeof(p21));
	memset (p14, '\0', sizeof(p14));

	len = strlen((const char *)passwd);
	if(len > (int)sizeof(p14)-1)
		len = sizeof(p14)-1;

	memcpy (p14, passwd, len);

	string_toupper ((char *) p14);
	E_P16 (p14, p21);

	smb_owf_encrypt (p21, c8, p24);
}

/****************************************************************************/

/* Convert a string into an NT UNICODE string.
   Note that regardless of processor type
   this must be in intel (little-endian)
   format. */
static int
local_mbstowcs (short *dst, const unsigned char *src, int len)
{
	int i;
	short val;

	for (i = 0; i < len; i++)
	{
		val = (*src++);
		WSET(dst,0,val);
		dst++;

		if (val == 0)
			break;
	}

	return i;
}

/* Creates the MD4 Hash of the users password in NT UNICODE. */
static void
E_md4hash (const unsigned char *passwd, unsigned char *p16)
{
	short wpwd[129];
	int len, size;

	/* Password cannot be longer than 128 characters */
	len = strlen ((char *) passwd);
	if (len > 128)
		len = 128;

	/* Password must be converted to NT unicode */
	local_mbstowcs (wpwd, passwd, len);
	wpwd[len] = 0; /* Ensure string is null terminated */

	/* Calculate size in bytes */
	size = len * sizeof (short);

	mdfour (p16, (unsigned char *) wpwd, size);
}

/* Does the DES encryption from the NT or LM MD4 hash. */
static void
smb_owf_encrypt (const unsigned char *passwd, const unsigned char *c8, unsigned char *p24)
{
	unsigned char p21[21];

	memset (p21, '\0', sizeof(p21));

	memcpy (p21, passwd, 16);
	E_P24 (p21, c8, p24);
}

/****************************************************************************/

/* Does the NT MD4 hash then DES encryption. */
void
smb_nt_encrypt (const unsigned char *passwd, const unsigned char *c8, unsigned char *p24)
{
	unsigned char p21[21];

	memset (p21, '\0', sizeof(p21));

	E_md4hash (passwd, p21);
	smb_owf_encrypt (p21, c8, p24);
}

/****************************************************************************/

static unsigned long A, B, C, D;

static unsigned long
F(unsigned long X, unsigned long Y, unsigned long Z)
{
	return (X & Y) | ((~X) & Z);
}

static unsigned long
G(unsigned long X, unsigned long Y, unsigned long Z)
{
	return (X & Y) | (X & Z) | (Y & Z);
}

static unsigned long
H(unsigned long X, unsigned long Y, unsigned long Z)
{
	return X ^ Y ^ Z;
}

static unsigned long
lshift (unsigned long x, int s)
{
	return (x << s) | (x >> (32 - s));
}

#define ROUND1(a,b,c,d,k,s) a = lshift(a + F(b,c,d) + X[k], s)
#define ROUND2(a,b,c,d,k,s) a = lshift(a + G(b,c,d) + X[k] + 0x5A827999UL,s)
#define ROUND3(a,b,c,d,k,s) a = lshift(a + H(b,c,d) + X[k] + 0x6ED9EBA1UL,s)

/* this applies md4 to 64 byte chunks */
static void
mdfour64 (unsigned long *M)
{
	unsigned long AA, BB, CC, DD;
	unsigned long X[16];

	memcpy(X,M,sizeof(X));

	AA = A;
	BB = B;
	CC = C;
	DD = D;

	ROUND1 (A, B, C, D, 0, 3);
	ROUND1 (D, A, B, C, 1, 7);
	ROUND1 (C, D, A, B, 2, 11);
	ROUND1 (B, C, D, A, 3, 19);
	ROUND1 (A, B, C, D, 4, 3);
	ROUND1 (D, A, B, C, 5, 7);
	ROUND1 (C, D, A, B, 6, 11);
	ROUND1 (B, C, D, A, 7, 19);
	ROUND1 (A, B, C, D, 8, 3);
	ROUND1 (D, A, B, C, 9, 7);
	ROUND1 (C, D, A, B, 10, 11);
	ROUND1 (B, C, D, A, 11, 19);
	ROUND1 (A, B, C, D, 12, 3);
	ROUND1 (D, A, B, C, 13, 7);
	ROUND1 (C, D, A, B, 14, 11);
	ROUND1 (B, C, D, A, 15, 19);

	ROUND2 (A, B, C, D, 0, 3);
	ROUND2 (D, A, B, C, 4, 5);
	ROUND2 (C, D, A, B, 8, 9);
	ROUND2 (B, C, D, A, 12, 13);
	ROUND2 (A, B, C, D, 1, 3);
	ROUND2 (D, A, B, C, 5, 5);
	ROUND2 (C, D, A, B, 9, 9);
	ROUND2 (B, C, D, A, 13, 13);
	ROUND2 (A, B, C, D, 2, 3);
	ROUND2 (D, A, B, C, 6, 5);
	ROUND2 (C, D, A, B, 10, 9);
	ROUND2 (B, C, D, A, 14, 13);
	ROUND2 (A, B, C, D, 3, 3);
	ROUND2 (D, A, B, C, 7, 5);
	ROUND2 (C, D, A, B, 11, 9);
	ROUND2 (B, C, D, A, 15, 13);

	ROUND3 (A, B, C, D, 0, 3);
	ROUND3 (D, A, B, C, 8, 9);
	ROUND3 (C, D, A, B, 4, 11);
	ROUND3 (B, C, D, A, 12, 15);
	ROUND3 (A, B, C, D, 2, 3);
	ROUND3 (D, A, B, C, 10, 9);
	ROUND3 (C, D, A, B, 6, 11);
	ROUND3 (B, C, D, A, 14, 15);
	ROUND3 (A, B, C, D, 1, 3);
	ROUND3 (D, A, B, C, 9, 9);
	ROUND3 (C, D, A, B, 5, 11);
	ROUND3 (B, C, D, A, 13, 15);
	ROUND3 (A, B, C, D, 3, 3);
	ROUND3 (D, A, B, C, 11, 9);
	ROUND3 (C, D, A, B, 7, 11);
	ROUND3 (B, C, D, A, 15, 15);

	A += AA;
	B += BB;
	C += CC;
	D += DD;
}

static void
copy64 (unsigned long *M, const unsigned char *in)
{
	int i;

	for (i = 0; i < 16; i++)
	{
		M[i] = (in[i * 4 + 3] << 24) | (in[i * 4 + 2] << 16) |
			(in[i * 4 + 1] << 8) | (in[i * 4 + 0] << 0);
	}
}

static void
copy4 (unsigned char *out, unsigned long x)
{
	out[0] = x & 0xFF;
	out[1] = (x >> 8) & 0xFF;
	out[2] = (x >> 16) & 0xFF;
	out[3] = (x >> 24) & 0xFF;
}

/* produce a md4 message digest from data of length n bytes */
static void
mdfour (unsigned char *out, const unsigned char *in, int n)
{
	unsigned char buf[128];
	unsigned long M[16];
	unsigned long b = n * 8;

	A = 0x67452301;
	B = 0xefcdab89;
	C = 0x98badcfe;
	D = 0x10325476;

	while (n > 64)
	{
		copy64 (M, in);
		mdfour64 (M);

		in += 64;
		n -= 64;
	}

	memset (buf, 0, sizeof(buf));
	memcpy (buf, in, n);
	buf[n] = 0x80;

	if (n <= 55)
	{
		copy4 (buf + 56, b);
		copy64 (M, buf);
		mdfour64 (M);
	}
	else
	{
		copy4 (buf + 120, b);
		copy64 (M, buf);
		mdfour64 (M);
		copy64 (M, buf + 64);
		mdfour64 (M);
	}

	memset (buf, 0, sizeof(buf));
	copy64 (M, buf);

	copy4 (out, A);
	copy4 (out + 4, B);
	copy4 (out + 8, C);
	copy4 (out + 12, D);
}