/*
    mdfour.c

    An implementation of MD4 designed for use in the samba SMB
    authentication protocol

    Copyright (C) 1997-1998  <NAME>

    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:

        Free Software Foundation, Inc.
        59 Temple Place - Suite 330
        Boston, MA  02111-1307, USA

    $Id: mdfour.c 7689 2007-11-12 14:28:40Z divverent $
 */

#include <string.h>     /* XoXus: needed for memset call */
#include "md4.h"

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

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

static struct mdfour *m;

#define F( X,Y,Z ) ( ( (X)&( Y ) ) | ( ( ~( X ) ) & ( Z ) ) )
#define G( X,Y,Z ) ( ( (X)&( Y ) ) | ( (X)&( Z ) ) | ( (Y)&( Z ) ) )
#define H( X,Y,Z ) ( ( X ) ^ ( Y ) ^ ( Z ) )
#define lshift( x,s ) ( ( ( x ) << ( s ) ) | ( ( 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] + 0x5A827999,s )
#define ROUND3( a,b,c,d,k,s ) a = lshift( a + H( b,c,d ) + X[k] + 0x6ED9EBA1,s )

/* this applies md4 to 64 byte chunks */
static void mdfour64( uint32_t *M ){
	int j;
	uint32_t AA, BB, CC, DD;
	uint32_t X[16];
	uint32_t A,B,C,D;

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

	A = m->A; B = m->B; C = m->C; D = m->D;
	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;

#ifdef LARGE_INT32
	A &= 0xFFFFFFFF; B &= 0xFFFFFFFF;
	C &= 0xFFFFFFFF; D &= 0xFFFFFFFF;
#endif

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

	m->A = A; m->B = B; m->C = C; m->D = D;
}

static void copy64( uint32_t *M, 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, uint32_t x ){
	out[0] = x & 0xFF;
	out[1] = ( x >> 8 ) & 0xFF;
	out[2] = ( x >> 16 ) & 0xFF;
	out[3] = ( x >> 24 ) & 0xFF;
}

void mdfour_begin( struct mdfour *md ){
	md->A = 0x67452301;
	md->B = 0xefcdab89;
	md->C = 0x98badcfe;
	md->D = 0x10325476;
	md->totalN = 0;
}


static void mdfour_tail( unsigned char *in, int n ){
	unsigned char buf[128];
	uint32_t M[16];
	uint32_t b;

	m->totalN += n;

	b = m->totalN * 8;

	memset( buf, 0, 128 );
	if ( n ) {
		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 );
	}
}

void mdfour_update( struct mdfour *md, unsigned char *in, int n ){
	uint32_t M[16];

// start of edit by Forest 'LordHavoc' Hale
// commented out to prevent crashing when length is 0
//	if (n == 0) mdfour_tail(in, n);
// end of edit by Forest 'LordHavoc' Hale

	m = md;

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

	mdfour_tail( in, n );
}


void mdfour_result( struct mdfour *md, unsigned char *out ){
	m = md;

	copy4( out, m->A );
	copy4( out + 4, m->B );
	copy4( out + 8, m->C );
	copy4( out + 12, m->D );
}


void mdfour( unsigned char *out, unsigned char *in, int n ){
	struct mdfour md;
	mdfour_begin( &md );
	mdfour_update( &md, in, n );
	mdfour_result( &md, out );
}

///////////////////////////////////////////////////////////////
//	MD4-based checksum utility functions
//
//	Copyright (C) 2000       <NAME> <<EMAIL>>
//
//	Author: <NAME>	<<EMAIL>>
//	Date: 01 Jan 2000

unsigned Com_BlockChecksum( void *buffer, int length ){
	int digest[4];
	unsigned val;

	mdfour( (unsigned char *) digest, (unsigned char *) buffer, length );

	val = digest[0] ^ digest[1] ^ digest[2] ^ digest[3];

	return val;
}

void Com_BlockFullChecksum( void *buffer, int len, unsigned char *outbuf ){
	mdfour( outbuf, (unsigned char *) buffer, len );
}
