/*
   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
   Modified by Steve French (sfrench@us.ibm.com) 2002,2004

   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.
*/

/* 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)
*/
#include <linux/slab.h>
#include "cifsencrypt.h"
#define uchar 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;
	char c[28];
	char d[28];
	char *cd;
	char (*ki)[48];
	char *pd1;
	char l[32], r[32];
	char *rl;

	/* Have to reduce stack usage */
	pk1 = kmalloc(56+56+64+64, GFP_KERNEL);
	if (pk1 == NULL)
		return;

	ki = kmalloc(16*48, GFP_KERNEL);
	if (ki == NULL) {
		kfree(pk1);
		return;
	}

	cd = pk1 + 56;
	pd1 = cd  + 56;
	rl = pd1 + 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;  /* er[48]  */
		char *erk; /* erk[48] */
		char b[8][6];
		char *cb;  /* cb[32]  */
		char *pcb; /* pcb[32] */
		char *r2;  /* r2[32]  */

		er = kmalloc(48+48+32+32+32, GFP_KERNEL);
		if (er == NULL) {
			kfree(pk1);
			kfree(ki);
			return;
		}
		erk = er+48;
		cb  = erk+48;
		pcb = cb+32;
		r2  = pcb+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];

		kfree(er);
	}

	concat(rl, r, l, 32, 32);

	permute(out, rl, perm6, 64);
	kfree(pk1);
	kfree(ki);
}

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; /* outb[64] */
	char *inb;  /* inb[64]  */
	char *keyb; /* keyb[64] */
	unsigned char key2[8];

	outb = kmalloc(64 * 3, GFP_KERNEL);
	if (outb == NULL)
		return;

	inb  = outb + 64;
	keyb = inb +  64;

	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)));
	}
	kfree(outb);
}

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 /* currently unsued */
static 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);
}

static 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);
}
/* these routines are currently unneeded, but may be
	needed later */
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);
}
#endif /* unneeded routines */