src/misc/md5.c

   1 /*****************************************************************************
   2  * md5.c: not so strong MD5 hashing
   3  *****************************************************************************
   4  * Copyright (C) 1995,1996,1998,1999,2001,2002,
   5  *               2003  Free Software Foundation, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU Lesser General Public License as published by
   9  * the Free Software Foundation; either version 2.1 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this program; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  20  *****************************************************************************/
  21
  22 /* md5.c - MD5 Message-Digest Algorithm
  23  *
  24  * According to the definition of MD5 in RFC 1321 from April 1992.
  25  * NOTE: This is *not* the same file as the one from glibc.
  26  * Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
  27  * heavily modified for GnuPG by Werner Koch <wk@gnupg.org>
  28  */
  29
  30 /* Test values:
  31  * ""                  D4 1D 8C D9 8F 00 B2 04  E9 80 09 98 EC F8 42 7E
  32  * "a"                 0C C1 75 B9 C0 F1 B6 A8  31 C3 99 E2 69 77 26 61
  33  * "abc                90 01 50 98 3C D2 4F B0  D6 96 3F 7D 28 E1 7F 72
  34  * "message digest"    F9 6B 69 7D 7C B7 93 8D  52 5A 2F 31 AA F1 61 D0
  35  */
  36
  37 #ifdef HAVE_CONFIG_H
  38 # include "config.h"
  39 #endif
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <assert.h>
  44
  45 #include <vlc_common.h>
  46 #include <vlc_hash.h>
  47
  48 typedef uint32_t u32;
  49 typedef uint8_t byte;
  50 #define rol(x,n) ( ((x) << (n)) | ((x) >> (32-(n))) )
  51
  52 typedef struct md5_s MD5_CONTEXT;
  53
  54
  55 static void
  56 md5_init( void *context )
  57 {
  58   MD5_CONTEXT *ctx = context;
  59
  60   ctx->A = 0x67452301;
  61   ctx->B = 0xefcdab89;
  62   ctx->C = 0x98badcfe;
  63   ctx->D = 0x10325476;
  64
  65   ctx->nblocks = 0;
  66   ctx->count = 0;
  67 }
  68
  69
  70 /* These are the four functions used in the four steps of the MD5 algorithm
  71    and defined in the RFC 1321.  The first function is a little bit optimized
  72    (as found in Colin Plumbs public domain implementation).  */
  73 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
  74 #define FF(b, c, d) (d ^ (b & (c ^ d)))
  75 #define FG(b, c, d) FF (d, b, c)
  76 #define FH(b, c, d) (b ^ c ^ d)
  77 #define FI(b, c, d) (c ^ (b | ~d))
  78
  79
  80 /****************
  81  * transform n*64 bytes
  82  */
  83 static void
  84 transform ( MD5_CONTEXT *ctx, const unsigned char *data )
  85 {
  86   u32 correct_words[16];
  87   register u32 A = ctx->A;
  88   register u32 B = ctx->B;
  89   register u32 C = ctx->C;
  90   register u32 D = ctx->D;
  91   u32 *cwp = correct_words;
  92
  93 #ifdef WORDS_BIGENDIAN
  94   {
  95     int i;
  96     byte *p2, *p1;
  97     for(i=0, p1=data, p2=(byte*)correct_words; i < 16; i++, p2 += 4 )
  98       {
  99         p2[3] = *p1++;
 100         p2[2] = *p1++;
 101         p2[1] = *p1++;
 102         p2[0] = *p1++;
 103       }
 104   }
 105 #else
 106   memcpy( correct_words, data, 64 );
 107 #endif
 108
 109
 110 #define OP(a, b, c, d, s, T) \
 111   do                                       \
 112     {                                      \
 113       a += FF (b, c, d) + (*cwp++) + T;    \
 114       a = rol(a, s);                       \
 115       a += b;                              \
 116     }                                      \
 117   while (0)
 118
 119   /* Before we start, one word about the strange constants.
 120      They are defined in RFC 1321 as
 121
 122      T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
 123   */
 124
 125   /* Round 1.  */
 126   OP (A, B, C, D,  7, 0xd76aa478);
 127   OP (D, A, B, C, 12, 0xe8c7b756);
 128   OP (C, D, A, B, 17, 0x242070db);
 129   OP (B, C, D, A, 22, 0xc1bdceee);
 130   OP (A, B, C, D,  7, 0xf57c0faf);
 131   OP (D, A, B, C, 12, 0x4787c62a);
 132   OP (C, D, A, B, 17, 0xa8304613);
 133   OP (B, C, D, A, 22, 0xfd469501);
 134   OP (A, B, C, D,  7, 0x698098d8);
 135   OP (D, A, B, C, 12, 0x8b44f7af);
 136   OP (C, D, A, B, 17, 0xffff5bb1);
 137   OP (B, C, D, A, 22, 0x895cd7be);
 138   OP (A, B, C, D,  7, 0x6b901122);
 139   OP (D, A, B, C, 12, 0xfd987193);
 140   OP (C, D, A, B, 17, 0xa679438e);
 141   OP (B, C, D, A, 22, 0x49b40821);
 142
 143 #undef OP
 144 #define OP(f, a, b, c, d, k, s, T)  \
 145     do                                                                \
 146       {                                                               \
 147         a += f (b, c, d) + correct_words[k] + T;                      \
 148         a = rol(a, s);                                                \
 149         a += b;                                                       \
 150       }                                                               \
 151     while (0)
 152
 153   /* Round 2.  */
 154   OP (FG, A, B, C, D,  1,  5, 0xf61e2562);
 155   OP (FG, D, A, B, C,  6,  9, 0xc040b340);
 156   OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
 157   OP (FG, B, C, D, A,  0, 20, 0xe9b6c7aa);
 158   OP (FG, A, B, C, D,  5,  5, 0xd62f105d);
 159   OP (FG, D, A, B, C, 10,  9, 0x02441453);
 160   OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
 161   OP (FG, B, C, D, A,  4, 20, 0xe7d3fbc8);
 162   OP (FG, A, B, C, D,  9,  5, 0x21e1cde6);
 163   OP (FG, D, A, B, C, 14,  9, 0xc33707d6);
 164   OP (FG, C, D, A, B,  3, 14, 0xf4d50d87);
 165   OP (FG, B, C, D, A,  8, 20, 0x455a14ed);
 166   OP (FG, A, B, C, D, 13,  5, 0xa9e3e905);
 167   OP (FG, D, A, B, C,  2,  9, 0xfcefa3f8);
 168   OP (FG, C, D, A, B,  7, 14, 0x676f02d9);
 169   OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
 170
 171   /* Round 3.  */
 172   OP (FH, A, B, C, D,  5,  4, 0xfffa3942);
 173   OP (FH, D, A, B, C,  8, 11, 0x8771f681);
 174   OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
 175   OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
 176   OP (FH, A, B, C, D,  1,  4, 0xa4beea44);
 177   OP (FH, D, A, B, C,  4, 11, 0x4bdecfa9);
 178   OP (FH, C, D, A, B,  7, 16, 0xf6bb4b60);
 179   OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
 180   OP (FH, A, B, C, D, 13,  4, 0x289b7ec6);
 181   OP (FH, D, A, B, C,  0, 11, 0xeaa127fa);
 182   OP (FH, C, D, A, B,  3, 16, 0xd4ef3085);
 183   OP (FH, B, C, D, A,  6, 23, 0x04881d05);
 184   OP (FH, A, B, C, D,  9,  4, 0xd9d4d039);
 185   OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
 186   OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
 187   OP (FH, B, C, D, A,  2, 23, 0xc4ac5665);
 188
 189   /* Round 4.  */
 190   OP (FI, A, B, C, D,  0,  6, 0xf4292244);
 191   OP (FI, D, A, B, C,  7, 10, 0x432aff97);
 192   OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
 193   OP (FI, B, C, D, A,  5, 21, 0xfc93a039);
 194   OP (FI, A, B, C, D, 12,  6, 0x655b59c3);
 195   OP (FI, D, A, B, C,  3, 10, 0x8f0ccc92);
 196   OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
 197   OP (FI, B, C, D, A,  1, 21, 0x85845dd1);
 198   OP (FI, A, B, C, D,  8,  6, 0x6fa87e4f);
 199   OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
 200   OP (FI, C, D, A, B,  6, 15, 0xa3014314);
 201   OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
 202   OP (FI, A, B, C, D,  4,  6, 0xf7537e82);
 203   OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
 204   OP (FI, C, D, A, B,  2, 15, 0x2ad7d2bb);
 205   OP (FI, B, C, D, A,  9, 21, 0xeb86d391);
 206
 207   /* Put checksum in context given as argument.  */
 208   ctx->A += A;
 209   ctx->B += B;
 210   ctx->C += C;
 211   ctx->D += D;
 212 }
 213
 214
 215
 216 /* The routine updates the message-digest context to
 217  * account for the presence of each of the characters inBuf[0..inLen-1]
 218  * in the message whose digest is being computed.
 219  */
 220 static void
 221 md5_write( void *context, const void *inbuf_arg , size_t inlen)
 222 {
 223   const unsigned char *inbuf = inbuf_arg;
 224   MD5_CONTEXT *hd = context;
 225
 226   if( hd->count == 64 )  /* flush the buffer */
 227     {
 228       transform( hd, hd->buf );
 229       hd->count = 0;
 230       hd->nblocks++;
 231     }
 232   if( !inbuf )
 233     return;
 234
 235   if( hd->count )
 236     {
 237       for( ; inlen && hd->count < 64; inlen-- )
 238         hd->buf[hd->count++] = *inbuf++;
 239       md5_write( hd, NULL, 0 );
 240       if( !inlen )
 241         return;
 242     }
 243
 244   while( inlen >= 64 )
 245     {
 246       transform( hd, inbuf );
 247       hd->count = 0;
 248       hd->nblocks++;
 249       inlen -= 64;
 250       inbuf += 64;
 251     }
 252   for( ; inlen && hd->count < 64; inlen-- )
 253     hd->buf[hd->count++] = *inbuf++;
 254
 255 }
 256
 257
 258
 259 /* The routine final terminates the message-digest computation and
 260  * ends with the desired message digest in mdContext->digest[0...15].
 261  * The handle is prepared for a new MD5 cycle.
 262  * Returns 16 bytes representing the digest.
 263  */
 264
 265 static void
 266 md5_final( void *context)
 267 {
 268   MD5_CONTEXT *hd = context;
 269   u32 t, msb, lsb;
 270   byte *p;
 271
 272   md5_write(hd, NULL, 0); /* flush */;
 273
 274   t = hd->nblocks;
 275   /* multiply by 64 to make a byte count */
 276   lsb = t << 6;
 277   msb = t >> 26;
 278   /* add the count */
 279   t = lsb;
 280   if( (lsb += hd->count) < t )
 281     msb++;
 282   /* multiply by 8 to make a bit count */
 283   t = lsb;
 284   lsb <<= 3;
 285   msb <<= 3;
 286   msb |= t >> 29;
 287
 288   if( hd->count < 56 )  /* enough room */
 289     {
 290       hd->buf[hd->count++] = 0x80; /* pad */
 291       while( hd->count < 56 )
 292         hd->buf[hd->count++] = 0;  /* pad */
 293     }
 294   else  /* need one extra block */
 295     {
 296       hd->buf[hd->count++] = 0x80; /* pad character */
 297       while( hd->count < 64 )
 298         hd->buf[hd->count++] = 0;
 299       md5_write(hd, NULL, 0);  /* flush */;
 300       memset(hd->buf, 0, 56 ); /* fill next block with zeroes */
 301     }
 302   /* append the 64 bit count */
 303   hd->buf[56] = lsb        ;
 304   hd->buf[57] = lsb >>  8;
 305   hd->buf[58] = lsb >> 16;
 306   hd->buf[59] = lsb >> 24;
 307   hd->buf[60] = msb        ;
 308   hd->buf[61] = msb >>  8;
 309   hd->buf[62] = msb >> 16;
 310   hd->buf[63] = msb >> 24;
 311   transform( hd, hd->buf );
 312
 313   p = hd->buf;
 314 #ifdef WORDS_BIGENDIAN
 315 #define X(a) do { *p++ = hd->a      ; *p++ = hd->a >> 8;      \
 316                   *p++ = hd->a >> 16; *p++ = hd->a >> 24; } while(0)
 317 #else /* little endian */
 318 #define X(a) do { *(u32*)p = (*hd).a ; p += 4; } while(0)
 319 #endif
 320   X(A);
 321   X(B);
 322   X(C);
 323   X(D);
 324 #undef X
 325
 326 }
 327
 328 #if 0
 329 static byte *
 330 md5_read( void *context )
 331 {
 332   MD5_CONTEXT *hd = (MD5_CONTEXT *) context;
 333   return hd->buf;
 334 }
 335 #endif
 336
 337 /* Public API */
 338 void vlc_hash_md5_Init(vlc_hash_md5_t *ctx)
 339 {
 340     md5_init(&ctx->priv);
 341 }
 342
 343 void vlc_hash_md5_Update(vlc_hash_md5_t *ctx, const void *data, size_t length)
 344 {
 345     md5_write(&ctx->priv, data, length);
 346 }
 347
 348 void vlc_hash_md5_Finish(vlc_hash_md5_t *ctx, void *output, size_t size)
 349 {
 350     assert(size >= VLC_HASH_MD5_DIGEST_SIZE);
 351     md5_final(&ctx->priv);
 352     memcpy(output, ctx->priv.buf, VLC_HASH_MD5_DIGEST_SIZE);
 353 }