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mdfour.c
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mdfour.c
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/*= -*- c-basic-offset: 4; indent-tabs-mode: nil; -*-
*
* librsync -- the library for network deltas
* $Id$
*
* Copyright (C) 2000, 2001 by Martin Pool <[email protected]>
* Copyright (C) 1997-1999 by Andrew Tridgell
* Copyright (C) 2002, 2003 by Donovan Baarda <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* MD4 message digest algorithm.
*
* TODO: Perhaps use the MD4 routine from OpenSSL if it's installed.
* It's probably not worth the trouble.
*
* This was originally written by Andrew Tridgell for use in Samba.
* It was then modified by;
*
* 2002-06-xx: Robert Weber <[email protected]>
* optimisations and fixed >512M support.
*
* 2002-06-27: Donovan Baarda <[email protected]>
* further optimisations and cleanups.
*
* 2004-09-09: Simon Law <[email protected]>
* handle little-endian machines that can't do unaligned access
* (e.g. ia64, pa-risc).
*/
#include <config.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "librsync.h"
#include "trace.h"
#include "types.h"
#include "mdfour.h"
#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)
/** padding data used for finalising */
static unsigned char PADDING[64] = {
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static void
rs_mdfour_block(rs_mdfour_t *md, void const *p);
/**
* Update an MD4 accumulator from a 64-byte chunk.
*
* This cannot be used for the last chunk of the file, which must be
* padded and contain the file length. rs_mdfour_tail() is used for
* that.
*
* \todo Recode to be fast, and to use system integer types. Perhaps
* if we can find an mdfour implementation already on the system
* (e.g. in OpenSSL) then we should use it instead of our own?
*
* \param X A series of integer, read little-endian from the file.
*/
static void
rs_mdfour64(rs_mdfour_t * m, const void *p)
{
uint32_t AA, BB, CC, DD;
uint32_t A, B, C, D;
const uint32_t *X = (const uint32_t *) p;
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;
m->A = A;
m->B = B;
m->C = C;
m->D = D;
}
/**
* These next routines are necessary because MD4 is specified in terms of
* little-endian int32s, but we have a byte buffer. On little-endian
* platforms, I think we can just use the buffer pointer directly.
*
* There are some nice endianness routines in glib, including assembler
* variants. If we ever depended on glib, then it could be good to use them
* instead. */
__inline static void copy4( /* @out@ */ unsigned char *out, uint32_t const x)
{
out[0] = x;
out[1] = x >> 8;
out[2] = x >> 16;
out[3] = x >> 24;
}
/* We need this if there is a uint64 */
/* [email protected] */
#ifdef HAVE_UINT64
inline static void
copy8( /* @out@ */ unsigned char *out, uint64_t const x)
{
out[0] = x;
out[1] = x >> 8;
out[2] = x >> 16;
out[3] = x >> 24;
out[4] = x >> 32;
out[5] = x >> 40;
out[6] = x >> 48;
out[7] = x >> 56;
}
#endif /* HAVE_UINT64 */
/* We only need this if we are big-endian */
#ifdef WORDS_BIGENDIAN
inline static void
copy64( /* @out@ */ uint32_t * M, unsigned char const *in)
{
int i=16;
while (i--) {
*M++ = (in[3] << 24) | (in[2] << 16) | (in[1] << 8) | in[0];
in += 4;
}
}
/**
* Accumulate a block, making appropriate conversions for bigendian
* machines.
*/
inline static void
rs_mdfour_block(rs_mdfour_t *md, void const *p)
{
uint32_t M[16];
copy64(M, p);
rs_mdfour64(md, M);
}
#else /* WORDS_BIGENDIAN */
# ifdef __i386__
/* If we are on an IA-32 machine, we can process directly. */
inline static void
rs_mdfour_block(rs_mdfour_t *md, void const *p)
{
rs_mdfour64(md,p);
}
# else /* !WORDS_BIGENDIAN && !__i386__ */
/* We are little-endian, but not on i386 and therefore may not be able
* to do unaligned access safely/quickly.
*
* So if the input is not already aligned correctly, copy it to an
* aligned buffer first. */
__inline static void
rs_mdfour_block(rs_mdfour_t *md, void const *p)
{
unsigned long ptrval = (unsigned long) p;
if (ptrval & 3) {
uint32_t M[16];
memcpy(M, p, 16 * sizeof(uint32_t));
rs_mdfour64(md, M);
} else {
rs_mdfour64(md, (const uint32_t *) p);
}
}
# endif /* ! __i386__ */
#endif /* WORDS_BIGENDIAN */
void
rs_mdfour_begin(rs_mdfour_t * md)
{
memset(md, 0, sizeof(*md));
md->A = 0x67452301;
md->B = 0xefcdab89;
md->C = 0x98badcfe;
md->D = 0x10325476;
#if HAVE_UINT64
md->totalN = 0;
#else
md->totalN_hi = md->totalN_lo = 0;
#endif
}
/**
* Handle special behaviour for processing the last block of a file
* when calculating its MD4 checksum.
*
* This must be called exactly once per file.
*
* Modified by Robert Weber to use uint64 in order that we can sum files
* > 2^29 = 512 MB.
*/
static void
rs_mdfour_tail(rs_mdfour_t * m)
{
#ifdef HAVE_UINT64
uint64_t b;
#else /* HAVE_UINT64 */
uint32_t b[2];
#endif /* HAVE_UINT64 */
unsigned char buf[8];
size_t pad_len;
/* convert the totalN byte count into a bit count buffer */
#ifdef HAVE_UINT64
b = m->totalN << 3;
copy8(buf, b);
#else /* HAVE_UINT64 */
b[0] = m->totalN_lo << 3;
b[1] = ((m->totalN_hi << 3) | (m->totalN_lo >> 29));
copy4(buf, b[0]);
copy4(buf + 4, b[1]);
#endif /* HAVE_UINT64 */
/* calculate length and process the padding data */
pad_len=(m->tail_len <56) ? (56 - m->tail_len) : (120 - m->tail_len);
rs_mdfour_update(m,PADDING,pad_len);
/* process the bit count */
rs_mdfour_update(m,buf,8);
}
/**
* Feed some data into the MD4 accumulator.
*
* \param n Number of bytes fed in.
*/
void
rs_mdfour_update(rs_mdfour_t * md, void const *in_void, size_t n)
{
unsigned char const *in = (unsigned char const *) in_void;
/* increment totalN */
#ifdef HAVE_UINT64
md->totalN+=n;
#else /* HAVE_UINT64 */
if ((md->totalN_lo += n) < n)
md->totalN_hi++;
#endif /* HAVE_UINT64 */
/* If there's any leftover data in the tail buffer, then first we have
* to make it up to a whole block to process it. */
if (md->tail_len) {
size_t tail_gap = 64 - md->tail_len;
if (tail_gap <= n) {
memcpy(&md->tail[md->tail_len], in, tail_gap);
rs_mdfour_block(md, md->tail);
in += tail_gap;
n -= tail_gap;
md->tail_len = 0;
}
}
/* process complete blocks of input */
while (n >= 64) {
rs_mdfour_block(md, in);
in += 64;
n -= 64;
}
/* Put remaining bytes onto tail*/
if (n) {
memcpy(&md->tail[md->tail_len], in, n);
md->tail_len += n;
}
}
void
rs_mdfour_result(rs_mdfour_t * md, unsigned char *out)
{
rs_mdfour_tail(md);
copy4(out, md->A);
copy4(out + 4, md->B);
copy4(out + 8, md->C);
copy4(out + 12, md->D);
}
void
rs_mdfour(unsigned char *out, void const *in, size_t n)
{
rs_mdfour_t md;
rs_mdfour_begin(&md);
rs_mdfour_update(&md, in, n);
rs_mdfour_result(&md, out);
}