/* 
   Unix SMB/CIFS implementation.

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

   Copyright (C) Andrew Tridgell 1998
   
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "libcli/auth/libcli_auth.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)
*/


static const uint8_t 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 uint8_t 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 uint8_t 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 uint8_t 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 uint8_t 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 uint8_t 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 uint8_t sc[16] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};

static const uint8_t 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 uint8_t *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(const uint8_t *str,uint8_t *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);
	}
}

/*
  basic des crypt using a 56 bit (7 byte) key
*/
void des_crypt56(uint8_t out[8], const uint8_t in[8], const uint8_t key[7], int forw)
{
	int i;
	char outb[64];
	char inb[64];
	char keyb[64];
	uint8_t 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(const uint8_t *p14,uint8_t *p16)
{
	const uint8_t sp8[8] = {0x4b, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25};
	des_crypt56(p16, sp8, p14, 1);
	des_crypt56(p16+8, sp8, p14+7, 1);
}

void E_P24(const uint8_t *p21, const uint8_t *c8, uint8_t *p24)
{
	des_crypt56(p24, c8, p21, 1);
	des_crypt56(p24+8, c8, p21+7, 1);
	des_crypt56(p24+16, c8, p21+14, 1);
}

void D_P16(const uint8_t *p14, const uint8_t *in, uint8_t *out)
{
	des_crypt56(out, in, p14, 0);
        des_crypt56(out+8, in+8, p14+7, 0);
}

void E_old_pw_hash( uint8_t *p14, const uint8_t *in, uint8_t *out)
{
        des_crypt56(out, in, p14, 1);
        des_crypt56(out+8, in+8, p14+7, 1);
}

/* des encryption with a 128 bit key */
void des_crypt128(uint8_t out[8], const uint8_t in[8], const uint8_t key[16])
{
	uint8_t buf[8];
	des_crypt56(buf, in, key, 1);
	des_crypt56(out, buf, key+9, 1);
}

/* des encryption with a 64 bit key */
void des_crypt64(uint8_t out[8], const uint8_t in[8], const uint8_t key[8], int forw)
{
	uint8_t buf[8];
	uint8_t key2[8];
	ZERO_STRUCT(key2);
	des_crypt56(buf, in, key, forw);
	key2[0] = key[7];
	des_crypt56(out, buf, key2, forw);
}

/* des encryption with a 112 bit (14 byte) key */
void des_crypt112(uint8_t out[8], const uint8_t in[8], const uint8_t key[14], int forw)
{
	uint8_t buf[8];
	des_crypt56(buf, in, key, forw);
	des_crypt56(out, buf, key+7, forw);
}

/* des encryption of a 16 byte lump of data with a 112 bit key */
void des_crypt112_16(uint8_t out[16], const uint8_t in[16], const uint8_t key[14], int forw)
{
        des_crypt56(out, in, key, forw);
        des_crypt56(out + 8, in + 8, key+7, forw);
}

/* Decode a sam password hash into a password.  The password hash is the
   same method used to store passwords in the NT registry.  The DES key
   used is based on the RID of the user. */
void sam_rid_crypt(unsigned int rid, const uint8_t *in, uint8_t *out, int forw)
{
	uint8_t s[14];

	s[0] = s[4] = s[8] = s[12] = (uint8_t)(rid & 0xFF);
	s[1] = s[5] = s[9] = s[13] = (uint8_t)((rid >> 8) & 0xFF);
	s[2] = s[6] = s[10]        = (uint8_t)((rid >> 16) & 0xFF);
	s[3] = s[7] = s[11]        = (uint8_t)((rid >> 24) & 0xFF);

	des_crypt56(out, in, s, forw);
	des_crypt56(out+8, in+8, s+7, forw);
}