/* 
   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 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 "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)
*/


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);
	}
}


void smbhash(uint8_t *out, const uint8_t *in, const uint8_t *key, 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};
	smbhash(p16, sp8, p14, 1);
	smbhash(p16+8, sp8, p14+7, 1);
}

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

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

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

void cred_hash1(uint8_t *out, const uint8_t *in, const uint8_t *key)
{
	uint8_t buf[8];

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

void cred_hash2(uint8_t *out, const uint8_t *in, const uint8_t *key, int forw)
{
	uint8_t buf[8];
	uint8_t key2[8];
	ZERO_STRUCT(key2);
	smbhash(buf, in, key, forw);
	key2[0] = key[7];
	smbhash(out, buf, key2, forw);
}

void cred_hash3(uint8_t *out, uint8_t *in, const uint8_t *key, int forw)
{
        uint8_t key2[8];
	ZERO_STRUCT(key2);
        smbhash(out, in, key, forw);
        key2[0] = key[7];
        smbhash(out + 8, in + 8, key2, forw);
}


void SamOEMhashBlob(uint8_t *data, int len, const DATA_BLOB *key)
{
	uint8_t s_box[256];
	uint8_t index_i = 0;
	uint8_t index_j = 0;
	uint8_t j = 0;
	int ind;
	
	for (ind = 0; ind < 256; ind++) {
		s_box[ind] = (uint8_t)ind;
	}

	for (ind = 0; ind < 256; ind++) {
		uint8_t tc;

		j += (s_box[ind] + key->data[ind%key->length]);

		tc = s_box[ind];
		s_box[ind] = s_box[j];
		s_box[j] = tc;
	}
	for (ind = 0; ind < len; ind++) {
		uint8_t tc;
		uint8_t 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];
	}
}

/*
  a varient that assumes a 16 byte key. This should be removed
  when the last user is gone
*/
void SamOEMhash(uint8_t *data, const uint8_t keystr[16], int len)
{
	DATA_BLOB key = data_blob(keystr, 16);
	
	SamOEMhashBlob(data, len, &key);

	data_blob_free(&key);
}


/* 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(uint_t 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);

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