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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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 (struct md5_ctx *ctx)
  66 {
  67   ctx->A = (md5_uint32) 0x67452301;
  68   ctx->B = (md5_uint32) 0xefcdab89;
  69   ctx->C = (md5_uint32) 0x98badcfe;
  70   ctx->D = (md5_uint32) 0x10325476;
  71
  72   ctx->total[0] = ctx->total[1] = 0;
  73   ctx->buflen = 0;
  74 }
  75
  76 /* Put result from CTX in first 16 bytes following RESBUF.  The result
  77    must be in little endian byte order.
  78
  79    IMPORTANT: On some systems it is required that RESBUF is correctly
  80    aligned for a 32 bits value.  */
  81 void *
  82 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
  83 {
  84   ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
  85   ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
  86   ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
  87   ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
  88
  89   return resbuf;
  90 }
  91
  92 /* Process the remaining bytes in the internal buffer and the usual
  93    prolog according to the standard and write the result to RESBUF.
  94
  95    IMPORTANT: On some systems it is required that RESBUF is correctly
  96    aligned for a 32 bits value.  */
  97 void *
  98 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
  99 {
 100   /* Take yet unprocessed bytes into account.  */
 101   md5_uint32 bytes = ctx->buflen;
 102   size_t pad;
 103
 104   /* Now count remaining bytes.  */
 105   ctx->total[0] += bytes;
 106   if (ctx->total[0] < bytes)
 107     ++ctx->total[1];
 108
 109   pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
 110   memcpy (&ctx->buffer[bytes], fillbuf, pad);
 111
 112   /* Put the 64-bit file length in *bits* at the end of the buffer.  */
 113   *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
 114   *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
 115                                                         (ctx->total[0] >> 29));
 116
 117   /* Process last bytes.  */
 118   md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
 119
 120   return md5_read_ctx (ctx, resbuf);
 121 }
 122
 123 /* Compute MD5 message digest for bytes read from STREAM.  The
 124    resulting message digest number will be written into the 16 bytes
 125    beginning at RESBLOCK.  */
 126 int
 127 md5_stream (FILE *stream, void *resblock)
 128 {
 129   /* Important: BLOCKSIZE must be a multiple of 64.  */
 130 #define BLOCKSIZE 4096
 131   struct md5_ctx ctx;
 132   char buffer[BLOCKSIZE + 72];
 133   size_t sum;
 134
 135   /* Initialize the computation context.  */
 136   md5_init_ctx (&ctx);
 137
 138   /* Iterate over full file contents.  */
 139   while (1)
 140     {
 141       /* We read the file in blocks of BLOCKSIZE bytes.  One call of the
 142          computation function processes the whole buffer so that with the
 143          next round of the loop another block can be read.  */
 144       size_t n;
 145       sum = 0;
 146
 147       /* Read block.  Take care for partial reads.  */
 148       do
 149         {
 150           n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
 151
 152           sum += n;
 153         }
 154       while (sum < BLOCKSIZE && n != 0);
 155       if (n == 0 && ferror (stream))
 156         return 1;
 157
 158       /* If end of file is reached, end the loop.  */
 159       if (n == 0)
 160         break;
 161
 162       /* Process buffer with BLOCKSIZE bytes.  Note that
 163                         BLOCKSIZE % 64 == 0
 164        */
 165       md5_process_block (buffer, BLOCKSIZE, &ctx);
 166     }
 167
 168   /* Add the last bytes if necessary.  */
 169   if (sum > 0)
 170     md5_process_bytes (buffer, sum, &ctx);
 171
 172   /* Construct result in desired memory.  */
 173   md5_finish_ctx (&ctx, resblock);
 174   return 0;
 175 }
 176
 177 /* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
 178    result is always in little endian byte order, so that a byte-wise
 179    output yields to the wanted ASCII representation of the message
 180    digest.  */
 181 void *
 182 md5_buffer (const char *buffer, size_t len, void *resblock)
 183 {
 184   struct md5_ctx ctx;
 185
 186   /* Initialize the computation context.  */
 187   md5_init_ctx (&ctx);
 188
 189   /* Process whole buffer but last len % 64 bytes.  */
 190   md5_process_bytes (buffer, len, &ctx);
 191
 192   /* Put result in desired memory area.  */
 193   return md5_finish_ctx (&ctx, resblock);
 194 }
 195
 196
 197 void
 198 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
 199 {
 200   /* When we already have some bits in our internal buffer concatenate
 201      both inputs first.  */
 202   if (ctx->buflen != 0)
 203     {
 204       size_t left_over = ctx->buflen;
 205       size_t add = 128 - left_over > len ? len : 128 - left_over;
 206
 207       memcpy (&ctx->buffer[left_over], buffer, add);
 208       ctx->buflen += add;
 209
 210       if (left_over + add > 64)
 211         {
 212           md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
 213           /* The regions in the following copy operation cannot overlap.  */
 214           memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
 215                   (left_over + add) & 63);
 216           ctx->buflen = (left_over + add) & 63;
 217         }
 218
 219       buffer = (const void *) ((const char *) buffer + add);
 220       len -= add;
 221     }
 222
 223   /* Process available complete blocks.  */
 224   if (len > 64)
 225     {
 226 #if !_STRING_ARCH_unaligned
 227 /* To check alignment gcc has an appropriate operator.  Other
 228    compilers don't.  */
 229 # if __GNUC__ >= 2
 230 #  define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0)
 231 # else
 232 #  define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0)
 233 # endif
 234       if (UNALIGNED_P (buffer))
 235         while (len > 64)
 236           {
 237             memcpy (ctx->buffer, buffer, 64);
 238             md5_process_block (ctx->buffer, 64, ctx);
 239             buffer = (const char *) buffer + 64;
 240             len -= 64;
 241           }
 242       else
 243 #endif
 244       md5_process_block (buffer, len & ~63, ctx);
 245       buffer = (const void *) ((const char *) buffer + (len & ~63));
 246       len &= 63;
 247     }
 248
 249   /* Move remaining bytes in internal buffer.  */
 250   if (len > 0)
 251     {
 252       memcpy (ctx->buffer, buffer, len);
 253       ctx->buflen = len;
 254     }
 255 }
 256
 257
 258 /* These are the four functions used in the four steps of the MD5 algorithm
 259    and defined in the RFC 1321.  The first function is a little bit optimized
 260    (as found in Colin Plumbs public domain implementation).  */
 261 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
 262 #define FF(b, c, d) (d ^ (b & (c ^ d)))
 263 #define FG(b, c, d) FF (d, b, c)
 264 #define FH(b, c, d) (b ^ c ^ d)
 265 #define FI(b, c, d) (c ^ (b | ~d))
 266
 267 /* Process LEN bytes of BUFFER, accumulating context into CTX.
 268    It is assumed that LEN % 64 == 0.  */
 269
 270 void
 271 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
 272 {
 273   md5_uint32 correct_words[16];
 274   const md5_uint32 *words = (const md5_uint32 *) buffer;
 275   size_t nwords = len / sizeof (md5_uint32);
 276   const md5_uint32 *endp = words + nwords;
 277   md5_uint32 A = ctx->A;
 278   md5_uint32 B = ctx->B;
 279   md5_uint32 C = ctx->C;
 280   md5_uint32 D = ctx->D;
 281
 282   /* First increment the byte count.  RFC 1321 specifies the possible
 283      length of the file up to 2^64 bits.  Here we only compute the
 284      number of bytes.  Do a double word increment.  */
 285   ctx->total[0] += len;
 286   if (ctx->total[0] < len)
 287     ++ctx->total[1];
 288
 289   /* Process all bytes in the buffer with 64 bytes in each round of
 290      the loop.  */
 291   while (words < endp)
 292     {
 293       md5_uint32 *cwp = correct_words;
 294       md5_uint32 A_save = A;
 295       md5_uint32 B_save = B;
 296       md5_uint32 C_save = C;
 297       md5_uint32 D_save = D;
 298
 299       /* First round: using the given function, the context and a constant
 300          the next context is computed.  Because the algorithms processing
 301          unit is a 32-bit word and it is determined to work on words in
 302          little endian byte order we perhaps have to change the byte order
 303          before the computation.  To reduce the work for the next steps
 304          we store the swapped words in the array CORRECT_WORDS.  */
 305
 306 #define OP(a, b, c, d, s, T)                                            \
 307       do                                                                \
 308         {                                                               \
 309           a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;             \
 310           ++words;                                                      \
 311           CYCLIC (a, s);                                                \
 312           a += b;                                                       \
 313         }                                                               \
 314       while (0)
 315
 316       /* It is unfortunate that C does not provide an operator for
 317          cyclic rotation.  Hope the C compiler is smart enough.  */
 318 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
 319
 320       /* Before we start, one word to the strange constants.
 321          They are defined in RFC 1321 as
 322
 323          T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
 324        */
 325
 326       /* Round 1.  */
 327       OP (A, B, C, D,  7, (md5_uint32) 0xd76aa478);
 328       OP (D, A, B, C, 12, (md5_uint32) 0xe8c7b756);
 329       OP (C, D, A, B, 17, (md5_uint32) 0x242070db);
 330       OP (B, C, D, A, 22, (md5_uint32) 0xc1bdceee);
 331       OP (A, B, C, D,  7, (md5_uint32) 0xf57c0faf);
 332       OP (D, A, B, C, 12, (md5_uint32) 0x4787c62a);
 333       OP (C, D, A, B, 17, (md5_uint32) 0xa8304613);
 334       OP (B, C, D, A, 22, (md5_uint32) 0xfd469501);
 335       OP (A, B, C, D,  7, (md5_uint32) 0x698098d8);
 336       OP (D, A, B, C, 12, (md5_uint32) 0x8b44f7af);
 337       OP (C, D, A, B, 17, (md5_uint32) 0xffff5bb1);
 338       OP (B, C, D, A, 22, (md5_uint32) 0x895cd7be);
 339       OP (A, B, C, D,  7, (md5_uint32) 0x6b901122);
 340       OP (D, A, B, C, 12, (md5_uint32) 0xfd987193);
 341       OP (C, D, A, B, 17, (md5_uint32) 0xa679438e);
 342       OP (B, C, D, A, 22, (md5_uint32) 0x49b40821);
 343
 344       /* For the second to fourth round we have the possibly swapped words
 345          in CORRECT_WORDS.  Redefine the macro to take an additional first
 346          argument specifying the function to use.  */
 347 #undef OP
 348 #define OP(a, b, c, d, k, s, T)                                         \
 349       do                                                                \
 350         {                                                               \
 351           a += FX (b, c, d) + correct_words[k] + T;                     \
 352           CYCLIC (a, s);                                                \
 353           a += b;                                                       \
 354         }                                                               \
 355       while (0)
 356
 357 #define FX(b, c, d) FG (b, c, d)
 358
 359       /* Round 2.  */
 360       OP (A, B, C, D,  1,  5, (md5_uint32) 0xf61e2562);
 361       OP (D, A, B, C,  6,  9, (md5_uint32) 0xc040b340);
 362       OP (C, D, A, B, 11, 14, (md5_uint32) 0x265e5a51);
 363       OP (B, C, D, A,  0, 20, (md5_uint32) 0xe9b6c7aa);
 364       OP (A, B, C, D,  5,  5, (md5_uint32) 0xd62f105d);
 365       OP (D, A, B, C, 10,  9, (md5_uint32) 0x02441453);
 366       OP (C, D, A, B, 15, 14, (md5_uint32) 0xd8a1e681);
 367       OP (B, C, D, A,  4, 20, (md5_uint32) 0xe7d3fbc8);
 368       OP (A, B, C, D,  9,  5, (md5_uint32) 0x21e1cde6);
 369       OP (D, A, B, C, 14,  9, (md5_uint32) 0xc33707d6);
 370       OP (C, D, A, B,  3, 14, (md5_uint32) 0xf4d50d87);
 371       OP (B, C, D, A,  8, 20, (md5_uint32) 0x455a14ed);
 372       OP (A, B, C, D, 13,  5, (md5_uint32) 0xa9e3e905);
 373       OP (D, A, B, C,  2,  9, (md5_uint32) 0xfcefa3f8);
 374       OP (C, D, A, B,  7, 14, (md5_uint32) 0x676f02d9);
 375       OP (B, C, D, A, 12, 20, (md5_uint32) 0x8d2a4c8a);
 376
 377 #undef FX
 378 #define FX(b, c, d) FH (b, c, d)
 379
 380       /* Round 3.  */
 381       OP (A, B, C, D,  5,  4, (md5_uint32) 0xfffa3942);
 382       OP (D, A, B, C,  8, 11, (md5_uint32) 0x8771f681);
 383       OP (C, D, A, B, 11, 16, (md5_uint32) 0x6d9d6122);
 384       OP (B, C, D, A, 14, 23, (md5_uint32) 0xfde5380c);
 385       OP (A, B, C, D,  1,  4, (md5_uint32) 0xa4beea44);
 386       OP (D, A, B, C,  4, 11, (md5_uint32) 0x4bdecfa9);
 387       OP (C, D, A, B,  7, 16, (md5_uint32) 0xf6bb4b60);
 388       OP (B, C, D, A, 10, 23, (md5_uint32) 0xbebfbc70);
 389       OP (A, B, C, D, 13,  4, (md5_uint32) 0x289b7ec6);
 390       OP (D, A, B, C,  0, 11, (md5_uint32) 0xeaa127fa);
 391       OP (C, D, A, B,  3, 16, (md5_uint32) 0xd4ef3085);
 392       OP (B, C, D, A,  6, 23, (md5_uint32) 0x04881d05);
 393       OP (A, B, C, D,  9,  4, (md5_uint32) 0xd9d4d039);
 394       OP (D, A, B, C, 12, 11, (md5_uint32) 0xe6db99e5);
 395       OP (C, D, A, B, 15, 16, (md5_uint32) 0x1fa27cf8);
 396       OP (B, C, D, A,  2, 23, (md5_uint32) 0xc4ac5665);
 397
 398 #undef FX
 399 #define FX(b, c, d) FI (b, c, d)
 400
 401       /* Round 4.  */
 402       OP (A, B, C, D,  0,  6, (md5_uint32) 0xf4292244);
 403       OP (D, A, B, C,  7, 10, (md5_uint32) 0x432aff97);
 404       OP (C, D, A, B, 14, 15, (md5_uint32) 0xab9423a7);
 405       OP (B, C, D, A,  5, 21, (md5_uint32) 0xfc93a039);
 406       OP (A, B, C, D, 12,  6, (md5_uint32) 0x655b59c3);
 407       OP (D, A, B, C,  3, 10, (md5_uint32) 0x8f0ccc92);
 408       OP (C, D, A, B, 10, 15, (md5_uint32) 0xffeff47d);
 409       OP (B, C, D, A,  1, 21, (md5_uint32) 0x85845dd1);
 410       OP (A, B, C, D,  8,  6, (md5_uint32) 0x6fa87e4f);
 411       OP (D, A, B, C, 15, 10, (md5_uint32) 0xfe2ce6e0);
 412       OP (C, D, A, B,  6, 15, (md5_uint32) 0xa3014314);
 413       OP (B, C, D, A, 13, 21, (md5_uint32) 0x4e0811a1);
 414       OP (A, B, C, D,  4,  6, (md5_uint32) 0xf7537e82);
 415       OP (D, A, B, C, 11, 10, (md5_uint32) 0xbd3af235);
 416       OP (C, D, A, B,  2, 15, (md5_uint32) 0x2ad7d2bb);
 417       OP (B, C, D, A,  9, 21, (md5_uint32) 0xeb86d391);
 418
 419       /* Add the starting values of the context.  */
 420       A += A_save;
 421       B += B_save;
 422       C += C_save;
 423       D += D_save;
 424     }
 425
 426   /* Put checksum in context given as argument.  */
 427   ctx->A = A;
 428   ctx->B = B;
 429   ctx->C = C;
 430   ctx->D = D;
 431 }