libiberty/md5.c

   1 /* md5.c - Functions to compute MD5 message digest of files or memory blocks
   2    according to the definition of MD5 in RFC 1321 from April 1992.
   3    Copyright (C) 1995, 1996 Free Software Foundation, Inc.
   4
   5    NOTE: This source is derived from an old version taken from the GNU C
   6    Library (glibc).
   7
   8    This program is free software; you can redistribute it and/or modify it
   9    under the terms of the GNU General Public License as published by the
  10    Free Software Foundation; either version 2, or (at your option) any
  11    later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software Foundation,
  20    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.  */
  23
  24 #ifdef HAVE_CONFIG_H
  25 # include <config.h>
  26 #endif
  27
  28 #include <sys/types.h>
  29
  30 #if STDC_HEADERS || defined _LIBC
  31 # include <stdlib.h>
  32 # include <string.h>
  33 #else
  34 # ifndef HAVE_MEMCPY
  35 #  define memcpy(d, s, n) bcopy ((s), (d), (n))
  36 # endif
  37 #endif
  38
  39 #include "ansidecl.h"
  40 #include "md5.h"
  41
  42 #ifdef _LIBC
  43 # include <endian.h>
  44 # if __BYTE_ORDER == __BIG_ENDIAN
  45 #  define WORDS_BIGENDIAN 1
  46 # endif
  47 #endif
  48
  49 #ifdef WORDS_BIGENDIAN
  50 # define SWAP(n)                                                        \
  51     (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
  52 #else
  53 # define SWAP(n) (n)
  54 #endif
  55
  56
  57 /* This array contains the bytes used to pad the buffer to the next
  58    64-byte boundary.  (RFC 1321, 3.1: Step 1)  */
  59 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */ };
  60
  61
  62 /* Initialize structure containing state of computation.
  63    (RFC 1321, 3.3: Step 3)  */
  64 void
  65 md5_init_ctx (ctx)
  66      struct md5_ctx *ctx;
  67 {
  68   ctx->A = 0x67452301;
  69   ctx->B = 0xefcdab89;
  70   ctx->C = 0x98badcfe;
  71   ctx->D = 0x10325476;
  72
  73   ctx->total[0] = ctx->total[1] = 0;
  74   ctx->buflen = 0;
  75 }
  76
  77 /* Put result from CTX in first 16 bytes following RESBUF.  The result
  78    must be in little endian byte order.
  79
  80    IMPORTANT: On some systems it is required that RESBUF is correctly
  81    aligned for a 32 bits value.  */
  82 void *
  83 md5_read_ctx (ctx, resbuf)
  84      const struct md5_ctx *ctx;
  85      void *resbuf;
  86 {
  87   ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
  88   ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
  89   ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
  90   ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
  91
  92   return resbuf;
  93 }
  94
  95 /* Process the remaining bytes in the internal buffer and the usual
  96    prolog according to the standard and write the result to RESBUF.
  97
  98    IMPORTANT: On some systems it is required that RESBUF is correctly
  99    aligned for a 32 bits value.  */
 100 void *
 101 md5_finish_ctx (ctx, resbuf)
 102      struct md5_ctx *ctx;
 103      void *resbuf;
 104 {
 105   /* Take yet unprocessed bytes into account.  */
 106   md5_uint32 bytes = ctx->buflen;
 107   size_t pad;
 108
 109   /* Now count remaining bytes.  */
 110   ctx->total[0] += bytes;
 111   if (ctx->total[0] < bytes)
 112     ++ctx->total[1];
 113
 114   pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
 115   memcpy (&ctx->buffer[bytes], fillbuf, pad);
 116
 117   /* Put the 64-bit file length in *bits* at the end of the buffer.  */
 118   *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
 119   *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
 120                                                         (ctx->total[0] >> 29));
 121
 122   /* Process last bytes.  */
 123   md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
 124
 125   return md5_read_ctx (ctx, resbuf);
 126 }
 127
 128 /* Compute MD5 message digest for bytes read from STREAM.  The
 129    resulting message digest number will be written into the 16 bytes
 130    beginning at RESBLOCK.  */
 131 int
 132 md5_stream (stream, resblock)
 133      FILE *stream;
 134      void *resblock;
 135 {
 136   /* Important: BLOCKSIZE must be a multiple of 64.  */
 137 #define BLOCKSIZE 4096
 138   struct md5_ctx ctx;
 139   char buffer[BLOCKSIZE + 72];
 140   size_t sum;
 141
 142   /* Initialize the computation context.  */
 143   md5_init_ctx (&ctx);
 144
 145   /* Iterate over full file contents.  */
 146   while (1)
 147     {
 148       /* We read the file in blocks of BLOCKSIZE bytes.  One call of the
 149          computation function processes the whole buffer so that with the
 150          next round of the loop another block can be read.  */
 151       size_t n;
 152       sum = 0;
 153
 154       /* Read block.  Take care for partial reads.  */
 155       do
 156         {
 157           n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
 158
 159           sum += n;
 160         }
 161       while (sum < BLOCKSIZE && n != 0);
 162       if (n == 0 && ferror (stream))
 163         return 1;
 164
 165       /* If end of file is reached, end the loop.  */
 166       if (n == 0)
 167         break;
 168
 169       /* Process buffer with BLOCKSIZE bytes.  Note that
 170                         BLOCKSIZE % 64 == 0
 171        */
 172       md5_process_block (buffer, BLOCKSIZE, &ctx);
 173     }
 174
 175   /* Add the last bytes if necessary.  */
 176   if (sum > 0)
 177     md5_process_bytes (buffer, sum, &ctx);
 178
 179   /* Construct result in desired memory.  */
 180   md5_finish_ctx (&ctx, resblock);
 181   return 0;
 182 }
 183
 184 /* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
 185    result is always in little endian byte order, so that a byte-wise
 186    output yields to the wanted ASCII representation of the message
 187    digest.  */
 188 void *
 189 md5_buffer (buffer, len, resblock)
 190      const char *buffer;
 191      size_t len;
 192      void *resblock;
 193 {
 194   struct md5_ctx ctx;
 195
 196   /* Initialize the computation context.  */
 197   md5_init_ctx (&ctx);
 198
 199   /* Process whole buffer but last len % 64 bytes.  */
 200   md5_process_bytes (buffer, len, &ctx);
 201
 202   /* Put result in desired memory area.  */
 203   return md5_finish_ctx (&ctx, resblock);
 204 }
 205
 206
 207 void
 208 md5_process_bytes (buffer, len, ctx)
 209      const void *buffer;
 210      size_t len;
 211      struct md5_ctx *ctx;
 212 {
 213   /* When we already have some bits in our internal buffer concatenate
 214      both inputs first.  */
 215   if (ctx->buflen != 0)
 216     {
 217       size_t left_over = ctx->buflen;
 218       size_t add = 128 - left_over > len ? len : 128 - left_over;
 219
 220       memcpy (&ctx->buffer[left_over], buffer, add);
 221       ctx->buflen += add;
 222
 223       if (left_over + add > 64)
 224         {
 225           md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
 226           /* The regions in the following copy operation cannot overlap.  */
 227           memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
 228                   (left_over + add) & 63);
 229           ctx->buflen = (left_over + add) & 63;
 230         }
 231
 232       buffer = (const char *) buffer + add;
 233       len -= add;
 234     }
 235
 236   /* Process available complete blocks.  */
 237   if (len > 64)
 238     {
 239       md5_process_block (buffer, len & ~63, ctx);
 240       buffer = (const char *) buffer + (len & ~63);
 241       len &= 63;
 242     }
 243
 244   /* Move remaining bytes in internal buffer.  */
 245   if (len > 0)
 246     {
 247       memcpy (ctx->buffer, buffer, len);
 248       ctx->buflen = len;
 249     }
 250 }
 251
 252
 253 /* These are the four functions used in the four steps of the MD5 algorithm
 254    and defined in the RFC 1321.  The first function is a little bit optimized
 255    (as found in Colin Plumbs public domain implementation).  */
 256 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
 257 #define FF(b, c, d) (d ^ (b & (c ^ d)))
 258 #define FG(b, c, d) FF (d, b, c)
 259 #define FH(b, c, d) (b ^ c ^ d)
 260 #define FI(b, c, d) (c ^ (b | ~d))
 261
 262 /* Process LEN bytes of BUFFER, accumulating context into CTX.
 263    It is assumed that LEN % 64 == 0.  */
 264
 265 void
 266 md5_process_block (buffer, len, ctx)
 267      const void *buffer;
 268      size_t len;
 269      struct md5_ctx *ctx;
 270 {
 271   md5_uint32 correct_words[16];
 272   const md5_uint32 *words = buffer;
 273   size_t nwords = len / sizeof (md5_uint32);
 274   const md5_uint32 *endp = words + nwords;
 275   md5_uint32 A = ctx->A;
 276   md5_uint32 B = ctx->B;
 277   md5_uint32 C = ctx->C;
 278   md5_uint32 D = ctx->D;
 279
 280   /* First increment the byte count.  RFC 1321 specifies the possible
 281      length of the file up to 2^64 bits.  Here we only compute the
 282      number of bytes.  Do a double word increment.  */
 283   ctx->total[0] += len;
 284   if (ctx->total[0] < len)
 285     ++ctx->total[1];
 286
 287   /* Process all bytes in the buffer with 64 bytes in each round of
 288      the loop.  */
 289   while (words < endp)
 290     {
 291       md5_uint32 *cwp = correct_words;
 292       md5_uint32 A_save = A;
 293       md5_uint32 B_save = B;
 294       md5_uint32 C_save = C;
 295       md5_uint32 D_save = D;
 296
 297       /* First round: using the given function, the context and a constant
 298          the next context is computed.  Because the algorithms processing
 299          unit is a 32-bit word and it is determined to work on words in
 300          little endian byte order we perhaps have to change the byte order
 301          before the computation.  To reduce the work for the next steps
 302          we store the swapped words in the array CORRECT_WORDS.  */
 303
 304 #define OP(a, b, c, d, s, T)                                            \
 305       do                                                                \
 306         {                                                               \
 307           a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;             \
 308           ++words;                                                      \
 309           CYCLIC (a, s);                                                \
 310           a += b;                                                       \
 311         }                                                               \
 312       while (0)
 313
 314       /* It is unfortunate that C does not provide an operator for
 315          cyclic rotation.  Hope the C compiler is smart enough.  */
 316 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
 317
 318       /* Before we start, one word to the strange constants.
 319          They are defined in RFC 1321 as
 320
 321          T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
 322        */
 323
 324       /* Round 1.  */
 325       OP (A, B, C, D,  7, 0xd76aa478);
 326       OP (D, A, B, C, 12, 0xe8c7b756);
 327       OP (C, D, A, B, 17, 0x242070db);
 328       OP (B, C, D, A, 22, 0xc1bdceee);
 329       OP (A, B, C, D,  7, 0xf57c0faf);
 330       OP (D, A, B, C, 12, 0x4787c62a);
 331       OP (C, D, A, B, 17, 0xa8304613);
 332       OP (B, C, D, A, 22, 0xfd469501);
 333       OP (A, B, C, D,  7, 0x698098d8);
 334       OP (D, A, B, C, 12, 0x8b44f7af);
 335       OP (C, D, A, B, 17, 0xffff5bb1);
 336       OP (B, C, D, A, 22, 0x895cd7be);
 337       OP (A, B, C, D,  7, 0x6b901122);
 338       OP (D, A, B, C, 12, 0xfd987193);
 339       OP (C, D, A, B, 17, 0xa679438e);
 340       OP (B, C, D, A, 22, 0x49b40821);
 341
 342       /* For the second to fourth round we have the possibly swapped words
 343          in CORRECT_WORDS.  Redefine the macro to take an additional first
 344          argument specifying the function to use.  */
 345 #undef OP
 346 #define OP(f, a, b, c, d, k, s, T)                                      \
 347       do                                                                \
 348         {                                                               \
 349           a += f (b, c, d) + correct_words[k] + T;                      \
 350           CYCLIC (a, s);                                                \
 351           a += b;                                                       \
 352         }                                                               \
 353       while (0)
 354
 355       /* Round 2.  */
 356       OP (FG, A, B, C, D,  1,  5, 0xf61e2562);
 357       OP (FG, D, A, B, C,  6,  9, 0xc040b340);
 358       OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
 359       OP (FG, B, C, D, A,  0, 20, 0xe9b6c7aa);
 360       OP (FG, A, B, C, D,  5,  5, 0xd62f105d);
 361       OP (FG, D, A, B, C, 10,  9, 0x02441453);
 362       OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
 363       OP (FG, B, C, D, A,  4, 20, 0xe7d3fbc8);
 364       OP (FG, A, B, C, D,  9,  5, 0x21e1cde6);
 365       OP (FG, D, A, B, C, 14,  9, 0xc33707d6);
 366       OP (FG, C, D, A, B,  3, 14, 0xf4d50d87);
 367       OP (FG, B, C, D, A,  8, 20, 0x455a14ed);
 368       OP (FG, A, B, C, D, 13,  5, 0xa9e3e905);
 369       OP (FG, D, A, B, C,  2,  9, 0xfcefa3f8);
 370       OP (FG, C, D, A, B,  7, 14, 0x676f02d9);
 371       OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
 372
 373       /* Round 3.  */
 374       OP (FH, A, B, C, D,  5,  4, 0xfffa3942);
 375       OP (FH, D, A, B, C,  8, 11, 0x8771f681);
 376       OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
 377       OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
 378       OP (FH, A, B, C, D,  1,  4, 0xa4beea44);
 379       OP (FH, D, A, B, C,  4, 11, 0x4bdecfa9);
 380       OP (FH, C, D, A, B,  7, 16, 0xf6bb4b60);
 381       OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
 382       OP (FH, A, B, C, D, 13,  4, 0x289b7ec6);
 383       OP (FH, D, A, B, C,  0, 11, 0xeaa127fa);
 384       OP (FH, C, D, A, B,  3, 16, 0xd4ef3085);
 385       OP (FH, B, C, D, A,  6, 23, 0x04881d05);
 386       OP (FH, A, B, C, D,  9,  4, 0xd9d4d039);
 387       OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
 388       OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
 389       OP (FH, B, C, D, A,  2, 23, 0xc4ac5665);
 390
 391       /* Round 4.  */
 392       OP (FI, A, B, C, D,  0,  6, 0xf4292244);
 393       OP (FI, D, A, B, C,  7, 10, 0x432aff97);
 394       OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
 395       OP (FI, B, C, D, A,  5, 21, 0xfc93a039);
 396       OP (FI, A, B, C, D, 12,  6, 0x655b59c3);
 397       OP (FI, D, A, B, C,  3, 10, 0x8f0ccc92);
 398       OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
 399       OP (FI, B, C, D, A,  1, 21, 0x85845dd1);
 400       OP (FI, A, B, C, D,  8,  6, 0x6fa87e4f);
 401       OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
 402       OP (FI, C, D, A, B,  6, 15, 0xa3014314);
 403       OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
 404       OP (FI, A, B, C, D,  4,  6, 0xf7537e82);
 405       OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
 406       OP (FI, C, D, A, B,  2, 15, 0x2ad7d2bb);
 407       OP (FI, B, C, D, A,  9, 21, 0xeb86d391);
 408
 409       /* Add the starting values of the context.  */
 410       A += A_save;
 411       B += B_save;
 412       C += C_save;
 413       D += D_save;
 414     }
 415
 416   /* Put checksum in context given as argument.  */
 417   ctx->A = A;
 418   ctx->B = B;
 419   ctx->C = C;
 420   ctx->D = D;
 421 }