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FFmpeg/libavutil/md5.c
Giorgio Vazzana c78cf00bd8 md5: consistently use uint32_t instead of unsigned int
Basically to make code clearer and adherent to the
standard. RFC 1321, on page 2 states

Let the symbol "+" denote addition of words (i.e., modulo-2^32
addition). Let X <<< s denote the 32-bit value obtained by circularly
shifting (rotating) X left by s bit positions.

on page 3, section 3.3 states:

A four-word buffer (A,B,C,D) is used to compute the message digest.
Here each of A, B, C, D is a 32-bit register.

so the algorithm needs to work with integers that are exactly 32bits
in length. And indeed in struct AVMD5 the MD buffer is declared as
"uint32_t ABCD[4];", while in the function that performs the block
transformation the state variables were "unsigned int"s. On
architectures where sizeof(unsigned int) != sizeof(uint32_t) this
could be a problem, although I can't name such an architecture from
the top of my head.
On a side note, both the reference implementation in RFC 1321 and the
gnulib implementation (used by md5sum program on GNU systems) use
uint32_t in the transform function.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2012-06-16 12:47:46 +02:00

206 lines
5.9 KiB
C

/*
* Copyright (C) 2006 Michael Niedermayer (michaelni@gmx.at)
* Copyright (C) 2003-2005 by Christopher R. Hertel (crh@ubiqx.mn.org)
*
* References:
* IETF RFC 1321: The MD5 Message-Digest Algorithm
* Ron Rivest. IETF, April, 1992
*
* based on http://ubiqx.org/libcifs/source/Auth/MD5.c
* from Christopher R. Hertel (crh@ubiqx.mn.org)
* Simplified, cleaned and IMO redundant comments removed by michael.
*
* If you use gcc, then version 4.1 or later and -fomit-frame-pointer is
* strongly recommended.
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include "bswap.h"
#include "intreadwrite.h"
#include "md5.h"
typedef struct AVMD5{
uint64_t len;
uint8_t block[64];
uint32_t ABCD[4];
} AVMD5;
const int av_md5_size = sizeof(AVMD5);
static const uint8_t S[4][4] = {
{ 7, 12, 17, 22 }, /* round 1 */
{ 5, 9, 14, 20 }, /* round 2 */
{ 4, 11, 16, 23 }, /* round 3 */
{ 6, 10, 15, 21 } /* round 4 */
};
static const uint32_t T[64] = { // T[i]= fabs(sin(i+1)<<32)
0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, /* round 1 */
0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, /* round 2 */
0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, /* round 3 */
0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, /* round 4 */
0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391,
};
#define CORE(i, a, b, c, d) do { \
t = S[i >> 4][i & 3]; \
a += T[i]; \
\
if (i < 32) { \
if (i < 16) a += (d ^ (b & (c ^ d))) + X[ i & 15]; \
else a += (c ^ (d & (c ^ b))) + X[(1 + 5*i) & 15]; \
} else { \
if (i < 48) a += (b ^ c ^ d) + X[(5 + 3*i) & 15]; \
else a += (c ^ (b | ~d)) + X[( 7*i) & 15]; \
} \
a = b + (a << t | a >> (32 - t)); \
} while (0)
static void body(uint32_t ABCD[4], uint32_t X[16])
{
int i av_unused;
uint32_t t;
uint32_t a = ABCD[3];
uint32_t b = ABCD[2];
uint32_t c = ABCD[1];
uint32_t d = ABCD[0];
#if HAVE_BIGENDIAN
for (i = 0; i < 16; i++)
X[i] = av_bswap32(X[i]);
#endif
#if CONFIG_SMALL
for (i = 0; i < 64; i++) {
CORE(i, a, b, c, d);
t = d;
d = c;
c = b;
b = a;
a = t;
}
#else
#define CORE2(i) \
CORE( i, a,b,c,d); CORE((i+1),d,a,b,c); \
CORE((i+2),c,d,a,b); CORE((i+3),b,c,d,a)
#define CORE4(i) CORE2(i); CORE2((i+4)); CORE2((i+8)); CORE2((i+12))
CORE4(0); CORE4(16); CORE4(32); CORE4(48);
#endif
ABCD[0] += d;
ABCD[1] += c;
ABCD[2] += b;
ABCD[3] += a;
}
void av_md5_init(AVMD5 *ctx)
{
ctx->len = 0;
ctx->ABCD[0] = 0x10325476;
ctx->ABCD[1] = 0x98badcfe;
ctx->ABCD[2] = 0xefcdab89;
ctx->ABCD[3] = 0x67452301;
}
void av_md5_update(AVMD5 *ctx, const uint8_t *src, const int len)
{
int i, j;
j = ctx->len & 63;
ctx->len += len;
for (i = 0; i < len; i++) {
ctx->block[j++] = src[i];
if (j == 64) {
body(ctx->ABCD, (uint32_t *) ctx->block);
j = 0;
}
}
}
void av_md5_final(AVMD5 *ctx, uint8_t *dst)
{
int i;
uint64_t finalcount = av_le2ne64(ctx->len << 3);
av_md5_update(ctx, "\200", 1);
while ((ctx->len & 63) != 56)
av_md5_update(ctx, "", 1);
av_md5_update(ctx, (uint8_t *)&finalcount, 8);
for (i = 0; i < 4; i++)
AV_WL32(dst + 4*i, ctx->ABCD[3 - i]);
}
void av_md5_sum(uint8_t *dst, const uint8_t *src, const int len)
{
AVMD5 ctx;
av_md5_init(&ctx);
av_md5_update(&ctx, src, len);
av_md5_final(&ctx, dst);
}
#ifdef TEST
#undef printf
#include <stdio.h>
static void print_md5(uint8_t *md5)
{
int i;
for (i = 0; i < 16; i++)
printf("%02x", md5[i]);
printf("\n");
}
int main(void){
uint8_t md5val[16];
int i;
uint8_t in[1000];
for (i = 0; i < 1000; i++)
in[i] = i * i;
av_md5_sum(md5val, in, 1000); print_md5(md5val);
av_md5_sum(md5val, in, 63); print_md5(md5val);
av_md5_sum(md5val, in, 64); print_md5(md5val);
av_md5_sum(md5val, in, 65); print_md5(md5val);
for (i = 0; i < 1000; i++)
in[i] = i % 127;
av_md5_sum(md5val, in, 999); print_md5(md5val);
return 0;
}
#endif