/*= -*- c-basic-offset: 4; indent-tabs-mode: nil; -*- * * librsync -- the library for network deltas * Id: mdfour.c,v 1.28 2001/04/09 14:59:42 mbp Exp * * Copyright (C) 2000, 2001 by Martin Pool * Copyright (C) 1997-1999 by Andrew Tridgell * * 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. */ #include #include #include #include #include "rsync.h" #include "trace.h" #include "types.h" static void (*rs_mdfour_block)(rs_mdfour_t *md, void const *p) = NULL; #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) /** * 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 two 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. */ 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; } } static void copy4( /* @out@ */ unsigned char *out, uint32_t const x) { out[0] = x & 0xFF; out[1] = (x >> 8) & 0xFF; out[2] = (x >> 16) & 0xFF; out[3] = (x >> 24) & 0xFF; } /** * Accumulate a block, making appropriate conversions for bigendian * machines. */ static void rs_mdfour_block_slow(rs_mdfour_t *md, void const *p) { uint32_t M[16]; copy64(M, p); rs_mdfour64(md, M); } static void rs_mdfour_choose_packer(void) { const uint32_t foo = 0x01020304; const char *p = (const char *)&foo; if (sizeof(uint32_t) != 4) rs_fatal("internal error: uint32_t is not really 32 bits!"); if (sizeof(foo) != 4) rs_fatal("internal error: something wierd about char arrays"); if (*p == 0x1) { rs_trace("big-endian machine"); rs_mdfour_block = rs_mdfour_block_slow; } else if (*p == 0x4) { rs_trace("little-endian machine"); rs_mdfour_block = rs_mdfour64; } else { rs_fatal("world is broken - can't determine endianness from %#x", *p); } } void rs_mdfour_begin(rs_mdfour_t * md) { if (!rs_mdfour_block) rs_mdfour_choose_packer(); memset(md, 0, sizeof(*md)); md->A = 0x67452301; md->B = 0xefcdab89; md->C = 0x98badcfe; md->D = 0x10325476; md->totalN = 0; } /** * Handle special behaviour for processing the last block of a file * when calculating its MD4 checksum. * * This must be called exactly once per file. */ static void rs_mdfour_tail(rs_mdfour_t * m, unsigned char const *in, int n) { unsigned char buf[128]; 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); rs_mdfour_block(m, buf); } else { copy4(buf + 120, b); rs_mdfour_block(m, buf); rs_mdfour_block(m, buf + 64); } } /** * 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; if (n == 0) return; if (md->tail_len) { size_t tail_gap = 64 - md->tail_len; /* If there's any leftover data in the tail buffer, then first * we have to make it up to a whole block and process it. */ if (tail_gap > n) tail_gap = n; memcpy(&md->tail[md->tail_len], in, tail_gap); md->tail_len += tail_gap; in += tail_gap; n -= tail_gap; if (md->tail_len != 64) return; rs_mdfour_block(md, md->tail); md->tail_len = 0; md->totalN += 64; } while (n >= 64) { rs_mdfour_block(md, in); in += 64; n -= 64; md->totalN += 64; } if (n) { memcpy(md->tail, in, n); md->tail_len = n; } } void rs_mdfour_result(rs_mdfour_t * md, unsigned char *out) { rs_mdfour_tail(md, md->tail, md->tail_len); 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); }