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gnupg/cipher/md5.c

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/* md5.c - MD5 Message-Digest Algorithm
* Copyright (C) 1995, 1996, 1998, 1999,
* 2000, 2001 Free Software Foundation, Inc.
*
* 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, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* According to the definition of MD5 in RFC 1321 from April 1992.
* NOTE: This is *not* the same file as the one from glibc.
*/
/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
/* Heavily modified for GnuPG by <wk@gnupg.org> */
/* Test values:
* "" D4 1D 8C D9 8F 00 B2 04 E9 80 09 98 EC F8 42 7E
* "a" 0C C1 75 B9 C0 F1 B6 A8 31 C3 99 E2 69 77 26 61
* "abc 90 01 50 98 3C D2 4F B0 D6 96 3F 7D 28 E1 7F 72
* "message digest" F9 6B 69 7D 7C B7 93 8D 52 5A 2F 31 AA F1 61 D0
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "util.h"
#include "memory.h"
#include "algorithms.h"
#include "bithelp.h"
typedef struct {
u32 A,B,C,D; /* chaining variables */
u32 nblocks;
byte buf[64];
int count;
} MD5_CONTEXT;
static void
md5_init( MD5_CONTEXT *ctx )
{
ctx->A = 0x67452301;
ctx->B = 0xefcdab89;
ctx->C = 0x98badcfe;
ctx->D = 0x10325476;
ctx->nblocks = 0;
ctx->count = 0;
}
/* These are the four functions used in the four steps of the MD5 algorithm
and defined in the RFC 1321. The first function is a little bit optimized
(as found in Colin Plumbs public domain implementation). */
/* #define FF(b, c, d) ((b & c) | (~b & d)) */
#define FF(b, c, d) (d ^ (b & (c ^ d)))
#define FG(b, c, d) FF (d, b, c)
#define FH(b, c, d) (b ^ c ^ d)
#define FI(b, c, d) (c ^ (b | ~d))
static void
burn_stack (int bytes)
{
char buf[128];
wipememory(buf,sizeof buf);
bytes -= sizeof buf;
if (bytes > 0)
burn_stack (bytes);
}
/****************
* transform n*64 bytes
*/
static void
/*transform( MD5_CONTEXT *ctx, const void *buffer, size_t len )*/
transform( MD5_CONTEXT *ctx, byte *data )
{
u32 correct_words[16];
u32 A = ctx->A;
u32 B = ctx->B;
u32 C = ctx->C;
u32 D = ctx->D;
u32 *cwp = correct_words;
#ifdef BIG_ENDIAN_HOST
{ int i;
byte *p2, *p1;
for(i=0, p1=data, p2=(byte*)correct_words; i < 16; i++, p2 += 4 ) {
p2[3] = *p1++;
p2[2] = *p1++;
p2[1] = *p1++;
p2[0] = *p1++;
}
}
#else
memcpy( correct_words, data, 64 );
#endif
#define OP(a, b, c, d, s, T) \
do \
{ \
a += FF (b, c, d) + (*cwp++) + T; \
a = rol(a, s); \
a += b; \
} \
while (0)
/* Before we start, one word about the strange constants.
They are defined in RFC 1321 as
T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
*/
/* Round 1. */
OP (A, B, C, D, 7, 0xd76aa478);
OP (D, A, B, C, 12, 0xe8c7b756);
OP (C, D, A, B, 17, 0x242070db);
OP (B, C, D, A, 22, 0xc1bdceee);
OP (A, B, C, D, 7, 0xf57c0faf);
OP (D, A, B, C, 12, 0x4787c62a);
OP (C, D, A, B, 17, 0xa8304613);
OP (B, C, D, A, 22, 0xfd469501);
OP (A, B, C, D, 7, 0x698098d8);
OP (D, A, B, C, 12, 0x8b44f7af);
OP (C, D, A, B, 17, 0xffff5bb1);
OP (B, C, D, A, 22, 0x895cd7be);
OP (A, B, C, D, 7, 0x6b901122);
OP (D, A, B, C, 12, 0xfd987193);
OP (C, D, A, B, 17, 0xa679438e);
OP (B, C, D, A, 22, 0x49b40821);
#undef OP
#define OP(f, a, b, c, d, k, s, T) \
do \
{ \
a += f (b, c, d) + correct_words[k] + T; \
a = rol(a, s); \
a += b; \
} \
while (0)
/* Round 2. */
OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
OP (FG, D, A, B, C, 6, 9, 0xc040b340);
OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
OP (FG, D, A, B, C, 10, 9, 0x02441453);
OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
/* Round 3. */
OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
OP (FH, D, A, B, C, 8, 11, 0x8771f681);
OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
OP (FH, B, C, D, A, 6, 23, 0x04881d05);
OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
/* Round 4. */
OP (FI, A, B, C, D, 0, 6, 0xf4292244);
OP (FI, D, A, B, C, 7, 10, 0x432aff97);
OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
OP (FI, C, D, A, B, 6, 15, 0xa3014314);
OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
/* Put checksum in context given as argument. */
ctx->A += A;
ctx->B += B;
ctx->C += C;
ctx->D += D;
}
/* The routine updates the message-digest context to
* account for the presence of each of the characters inBuf[0..inLen-1]
* in the message whose digest is being computed.
*/
static void
md5_write( MD5_CONTEXT *hd, byte *inbuf, size_t inlen)
{
if( hd->count == 64 ) { /* flush the buffer */
transform( hd, hd->buf );
burn_stack (80+6*sizeof(void*));
hd->count = 0;
hd->nblocks++;
}
if( !inbuf )
return;
if( hd->count ) {
for( ; inlen && hd->count < 64; inlen-- )
hd->buf[hd->count++] = *inbuf++;
md5_write( hd, NULL, 0 );
if( !inlen )
return;
}
while( inlen >= 64 ) {
transform( hd, inbuf );
hd->count = 0;
hd->nblocks++;
inlen -= 64;
inbuf += 64;
}
burn_stack (80+6*sizeof(void*));
for( ; inlen && hd->count < 64; inlen-- )
hd->buf[hd->count++] = *inbuf++;
}
/* The routine final terminates the message-digest computation and
* ends with the desired message digest in mdContext->digest[0...15].
* The handle is prepared for a new MD5 cycle.
* Returns 16 bytes representing the digest.
*/
static void
md5_final( MD5_CONTEXT *hd )
{
u32 t, msb, lsb;
byte *p;
md5_write(hd, NULL, 0); /* flush */;
t = hd->nblocks;
/* multiply by 64 to make a byte count */
lsb = t << 6;
msb = t >> 26;
/* add the count */
t = lsb;
if( (lsb += hd->count) < t )
msb++;
/* multiply by 8 to make a bit count */
t = lsb;
lsb <<= 3;
msb <<= 3;
msb |= t >> 29;
if( hd->count < 56 ) { /* enough room */
hd->buf[hd->count++] = 0x80; /* pad */
while( hd->count < 56 )
hd->buf[hd->count++] = 0; /* pad */
}
else { /* need one extra block */
hd->buf[hd->count++] = 0x80; /* pad character */
while( hd->count < 64 )
hd->buf[hd->count++] = 0;
md5_write(hd, NULL, 0); /* flush */;
memset(hd->buf, 0, 56 ); /* fill next block with zeroes */
}
/* append the 64 bit count */
hd->buf[56] = lsb ;
hd->buf[57] = lsb >> 8;
hd->buf[58] = lsb >> 16;
hd->buf[59] = lsb >> 24;
hd->buf[60] = msb ;
hd->buf[61] = msb >> 8;
hd->buf[62] = msb >> 16;
hd->buf[63] = msb >> 24;
transform( hd, hd->buf );
burn_stack (80+6*sizeof(void*));
p = hd->buf;
#ifdef BIG_ENDIAN_HOST
#define X(a) do { *p++ = hd-> a ; *p++ = hd-> a >> 8; \
*p++ = hd-> a >> 16; *p++ = hd-> a >> 24; } while(0)
#else /* little endian */
#define X(a) do { *(u32*)p = hd-> a ; p += 4; } while(0)
#endif
X(A);
X(B);
X(C);
X(D);
#undef X
}
static byte *
md5_read( MD5_CONTEXT *hd )
{
return hd->buf;
}
/****************
* Return some information about the algorithm. We need algo here to
* distinguish different flavors of the algorithm.
* Returns: A pointer to string describing the algorithm or NULL if
* the ALGO is invalid.
*/
const char *
md5_get_info( int algo, size_t *contextsize,
byte **r_asnoid, int *r_asnlen, int *r_mdlen,
void (**r_init)( void *c ),
void (**r_write)( void *c, byte *buf, size_t nbytes ),
void (**r_final)( void *c ),
byte *(**r_read)( void *c )
)
{
static byte asn[18] = /* Object ID is 1.2.840.113549.2.5 */
{ 0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, 0x2a, 0x86,0x48,
0x86, 0xf7, 0x0d, 0x02, 0x05, 0x05, 0x00, 0x04, 0x10 };
if( algo != 1 )
return NULL;
*contextsize = sizeof(MD5_CONTEXT);
*r_asnoid = asn;
*r_asnlen = DIM(asn);
*r_mdlen = 16;
*(void (**)(MD5_CONTEXT *))r_init = md5_init;
*(void (**)(MD5_CONTEXT *, byte*, size_t))r_write = md5_write;
*(void (**)(MD5_CONTEXT *))r_final = md5_final;
*(byte *(**)(MD5_CONTEXT *))r_read = md5_read;
return "MD5";
}
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