/* 
   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"

/* 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)
*/


#define uchar unsigned char

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

static const 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, const char *in, const 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 x_or(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);

		x_or(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);

		x_or(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);
}

/* Convert a 7 byte string to an 8 byte key. */
static void str_to_key(const unsigned char str[7], unsigned char key[8])
{
	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);
	}
}


void des_crypt56(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)));
	}
}

void E_P16(const unsigned char *p14,unsigned char *p16)
{
	unsigned char 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 unsigned char *p21, const unsigned char *c8, unsigned char *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 unsigned char *p14, const unsigned char *in, unsigned char *out)
{
	des_crypt56(out, in, p14, 0);
        des_crypt56(out+8, in+8, p14+7, 0);
}

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

/* forward des encryption with a 128 bit key */
void des_crypt128(unsigned char out[8], const unsigned char in[8], const unsigned char key[16])
{
	unsigned char buf[8];

	des_crypt56(buf, in, key, 1);
	des_crypt56(out, buf, key+9, 1);
}

/* forward des encryption with a 64 bit key */
void des_crypt64(unsigned char out[8], const unsigned char in[8], const unsigned char key[8])
{
	unsigned char buf[8];
	unsigned char key2[8];

	memset(key2,'\0',8);
	des_crypt56(buf, in, key, 1);
	key2[0] = key[7];
	des_crypt56(out, buf, key2, 1);
}

/* des encryption with a 112 bit (14 byte) key */
/* Note that if the forw is 1, and key is actually 8 bytes of key, followed by 6 bytes of zeros,
   this is identical to des_crypt64(). JRA. */

void des_crypt112(unsigned char out[8], const unsigned char in[8], const unsigned char key[14], int forw)
{
	unsigned char buf[8];
	des_crypt56(buf, in, key, forw);
	des_crypt56(out, buf, key+7, forw);
}

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

	memset(key2,'\0',8);
        des_crypt56(out, in, key, forw);
        key2[0] = key[7];
        des_crypt56(out + 8, in + 8, key2, forw);
}

/* des encryption of a 16 byte lump of data with a 112 bit key */
/* Note that if the key is actually 8 bytes of key, followed by 6 bytes of zeros,
   this is identical to cred_hash3(). JRA. */

void des_crypt112_16(unsigned char out[16], unsigned char in[16], const unsigned char key[14], int forw)
{
	des_crypt56(out, in, key, forw);
	des_crypt56(out + 8, in + 8, key+7, forw);
}

/*****************************************************************
 arc4 crypt/decrypt with a 16 byte key.
*****************************************************************/

void SamOEMhash( unsigned char *data, const unsigned char key[16], size_t len)
{
	struct arcfour_state arc4_state;
	DATA_BLOB keyblob = { key, 16 };

	arcfour_init(&arc4_state, &keyblob);
	arcfour_crypt_sbox(&arc4_state, data, len);
}

void SamOEMhashBlob( unsigned char *data, size_t len, DATA_BLOB *key)
{
	struct arcfour_state arc4_state;

	arcfour_init(&arc4_state, key);
	arcfour_crypt_sbox(&arc4_state, data, len);
}

/* 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_pwd_hash(unsigned int rid, const uchar *in, uchar *out, int forw)
{
	uchar s[14];

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

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