/*
   Unix SMB/CIFS implementation.
   a implementation of MD4 designed for use in the SMB authentication protocol
   Copyright (C) Andrew Tridgell 1997-1998.

   $Id: crypt-md4.c 30393 2009-10-07 22:36:33Z guy $

   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.
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <glib.h>
#include <string.h>

#include <epan/crypt/crypt-md4.h>

/* NOTE: This code makes no attempt to be fast!

   It assumes that a int is at least 32 bits long
*/

static guint32 A, B, C, D;

static guint32 F(guint32 X, guint32 Y, guint32 Z)
{
	return (X&Y) | ((~X)&Z);
}

static guint32 G(guint32 X, guint32 Y, guint32 Z)
{
	return (X&Y) | (X&Z) | (Y&Z);
}

static guint32 H(guint32 X, guint32 Y, guint32 Z)
{
	return X^Y^Z;
}

static guint32 lshift(guint32 x, int s)
{
	x &= 0xFFFFFFFF;
	return ((x<<s)&0xFFFFFFFF) | (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] + (guint32)0x5A827999,s)
#define ROUND3(a,b,c,d,k,s) a = lshift(a + H(b,c,d) + X[k] + (guint32)0x6ED9EBA1,s)

/* this applies md4 to 64 byte chunks */
static void mdfour64(guint32 *M)
{
	int j;
	guint32 AA, BB, CC, DD;
	guint32 X[16];

	for (j=0;j<16;j++)
		X[j] = M[j];

	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;

	A &= 0xFFFFFFFF; B &= 0xFFFFFFFF;
	C &= 0xFFFFFFFF; D &= 0xFFFFFFFF;

	for (j=0;j<16;j++)
		X[j] = 0;
}

static void copy64(guint32 *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, guint32 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 */
void crypt_md4(unsigned char *out, const unsigned char *in, size_t n)
{
	unsigned char buf[128];
	guint32 M[16];
	guint32 b = (guint32)(n * 8);
	int i;

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

	while (n > 64) {
		copy64(M, in);
		mdfour64(M);
		in += 64;
		n -= 64;
	}

	for (i=0;i<128;i++)
		buf[i] = 0;
	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);
	}

	for (i=0;i<128;i++)
		buf[i] = 0;
	copy64(M, buf);

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

	A = B = C = D = 0;
}


