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       md5_process_block (buffer, len & ~63, ctx);
 227       buffer = (const void *) ((const char *) buffer + (len & ~63));
 228       len &= 63;
 229     }
 230
 231   /* Move remaining bytes in internal buffer.  */
 232   if (len > 0)
 233     {
 234       memcpy (ctx->buffer, buffer, len);
 235       ctx->buflen = len;
 236     }
 237 }
 238
 239
 240 /* These are the four functions used in the four steps of the MD5 algorithm
 241    and defined in the RFC 1321.  The first function is a little bit optimized
 242    (as found in Colin Plumbs public domain implementation).  */
 243 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
 244 #define FF(b, c, d) (d ^ (b & (c ^ d)))
 245 #define FG(b, c, d) FF (d, b, c)
 246 #define FH(b, c, d) (b ^ c ^ d)
 247 #define FI(b, c, d) (c ^ (b | ~d))
 248
 249 /* Process LEN bytes of BUFFER, accumulating context into CTX.
 250    It is assumed that LEN % 64 == 0.  */
 251
 252 void
 253 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
 254 {
 255   md5_uint32 correct_words[16];
 256   const md5_uint32 *words = (const md5_uint32 *) buffer;
 257   size_t nwords = len / sizeof (md5_uint32);
 258   const md5_uint32 *endp = words + nwords;
 259   md5_uint32 A = ctx->A;
 260   md5_uint32 B = ctx->B;
 261   md5_uint32 C = ctx->C;
 262   md5_uint32 D = ctx->D;
 263
 264   /* First increment the byte count.  RFC 1321 specifies the possible
 265      length of the file up to 2^64 bits.  Here we only compute the
 266      number of bytes.  Do a double word increment.  */
 267   ctx->total[0] += len;
 268   if (ctx->total[0] < len)
 269     ++ctx->total[1];
 270
 271   /* Process all bytes in the buffer with 64 bytes in each round of
 272      the loop.  */
 273   while (words < endp)
 274     {
 275       md5_uint32 *cwp = correct_words;
 276       md5_uint32 A_save = A;
 277       md5_uint32 B_save = B;
 278       md5_uint32 C_save = C;
 279       md5_uint32 D_save = D;
 280
 281       /* First round: using the given function, the context and a constant
 282          the next context is computed.  Because the algorithms processing
 283          unit is a 32-bit word and it is determined to work on words in
 284          little endian byte order we perhaps have to change the byte order
 285          before the computation.  To reduce the work for the next steps
 286          we store the swapped words in the array CORRECT_WORDS.  */
 287
 288 #define OP(a, b, c, d, s, T)                                            \
 289       do                                                                \
 290         {                                                               \
 291           a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;             \
 292           ++words;                                                      \
 293           CYCLIC (a, s);                                                \
 294           a += b;                                                       \
 295         }                                                               \
 296       while (0)
 297
 298       /* It is unfortunate that C does not provide an operator for
 299          cyclic rotation.  Hope the C compiler is smart enough.  */
 300 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
 301
 302       /* Before we start, one word to the strange constants.
 303          They are defined in RFC 1321 as
 304
 305          T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
 306        */
 307
 308       /* Round 1.  */
 309       OP (A, B, C, D,  7, (md5_uint32) 0xd76aa478);
 310       OP (D, A, B, C, 12, (md5_uint32) 0xe8c7b756);
 311       OP (C, D, A, B, 17, (md5_uint32) 0x242070db);
 312       OP (B, C, D, A, 22, (md5_uint32) 0xc1bdceee);
 313       OP (A, B, C, D,  7, (md5_uint32) 0xf57c0faf);
 314       OP (D, A, B, C, 12, (md5_uint32) 0x4787c62a);
 315       OP (C, D, A, B, 17, (md5_uint32) 0xa8304613);
 316       OP (B, C, D, A, 22, (md5_uint32) 0xfd469501);
 317       OP (A, B, C, D,  7, (md5_uint32) 0x698098d8);
 318       OP (D, A, B, C, 12, (md5_uint32) 0x8b44f7af);
 319       OP (C, D, A, B, 17, (md5_uint32) 0xffff5bb1);
 320       OP (B, C, D, A, 22, (md5_uint32) 0x895cd7be);
 321       OP (A, B, C, D,  7, (md5_uint32) 0x6b901122);
 322       OP (D, A, B, C, 12, (md5_uint32) 0xfd987193);
 323       OP (C, D, A, B, 17, (md5_uint32) 0xa679438e);
 324       OP (B, C, D, A, 22, (md5_uint32) 0x49b40821);
 325
 326       /* For the second to fourth round we have the possibly swapped words
 327          in CORRECT_WORDS.  Redefine the macro to take an additional first
 328          argument specifying the function to use.  */
 329 #undef OP
 330 #define OP(a, b, c, d, k, s, T)                                         \
 331       do                                                                \
 332         {                                                               \
 333           a += FX (b, c, d) + correct_words[k] + T;                     \
 334           CYCLIC (a, s);                                                \
 335           a += b;                                                       \
 336         }                                                               \
 337       while (0)
 338
 339 #define FX(b, c, d) FG (b, c, d)
 340
 341       /* Round 2.  */
 342       OP (A, B, C, D,  1,  5, (md5_uint32) 0xf61e2562);
 343       OP (D, A, B, C,  6,  9, (md5_uint32) 0xc040b340);
 344       OP (C, D, A, B, 11, 14, (md5_uint32) 0x265e5a51);
 345       OP (B, C, D, A,  0, 20, (md5_uint32) 0xe9b6c7aa);
 346       OP (A, B, C, D,  5,  5, (md5_uint32) 0xd62f105d);
 347       OP (D, A, B, C, 10,  9, (md5_uint32) 0x02441453);
 348       OP (C, D, A, B, 15, 14, (md5_uint32) 0xd8a1e681);
 349       OP (B, C, D, A,  4, 20, (md5_uint32) 0xe7d3fbc8);
 350       OP (A, B, C, D,  9,  5, (md5_uint32) 0x21e1cde6);
 351       OP (D, A, B, C, 14,  9, (md5_uint32) 0xc33707d6);
 352       OP (C, D, A, B,  3, 14, (md5_uint32) 0xf4d50d87);
 353       OP (B, C, D, A,  8, 20, (md5_uint32) 0x455a14ed);
 354       OP (A, B, C, D, 13,  5, (md5_uint32) 0xa9e3e905);
 355       OP (D, A, B, C,  2,  9, (md5_uint32) 0xfcefa3f8);
 356       OP (C, D, A, B,  7, 14, (md5_uint32) 0x676f02d9);
 357       OP (B, C, D, A, 12, 20, (md5_uint32) 0x8d2a4c8a);
 358
 359 #undef FX
 360 #define FX(b, c, d) FH (b, c, d)
 361
 362       /* Round 3.  */
 363       OP (A, B, C, D,  5,  4, (md5_uint32) 0xfffa3942);
 364       OP (D, A, B, C,  8, 11, (md5_uint32) 0x8771f681);
 365       OP (C, D, A, B, 11, 16, (md5_uint32) 0x6d9d6122);
 366       OP (B, C, D, A, 14, 23, (md5_uint32) 0xfde5380c);
 367       OP (A, B, C, D,  1,  4, (md5_uint32) 0xa4beea44);
 368       OP (D, A, B, C,  4, 11, (md5_uint32) 0x4bdecfa9);
 369       OP (C, D, A, B,  7, 16, (md5_uint32) 0xf6bb4b60);
 370       OP (B, C, D, A, 10, 23, (md5_uint32) 0xbebfbc70);
 371       OP (A, B, C, D, 13,  4, (md5_uint32) 0x289b7ec6);
 372       OP (D, A, B, C,  0, 11, (md5_uint32) 0xeaa127fa);
 373       OP (C, D, A, B,  3, 16, (md5_uint32) 0xd4ef3085);
 374       OP (B, C, D, A,  6, 23, (md5_uint32) 0x04881d05);
 375       OP (A, B, C, D,  9,  4, (md5_uint32) 0xd9d4d039);
 376       OP (D, A, B, C, 12, 11, (md5_uint32) 0xe6db99e5);
 377       OP (C, D, A, B, 15, 16, (md5_uint32) 0x1fa27cf8);
 378       OP (B, C, D, A,  2, 23, (md5_uint32) 0xc4ac5665);
 379
 380 #undef FX
 381 #define FX(b, c, d) FI (b, c, d)
 382
 383       /* Round 4.  */
 384       OP (A, B, C, D,  0,  6, (md5_uint32) 0xf4292244);
 385       OP (D, A, B, C,  7, 10, (md5_uint32) 0x432aff97);
 386       OP (C, D, A, B, 14, 15, (md5_uint32) 0xab9423a7);
 387       OP (B, C, D, A,  5, 21, (md5_uint32) 0xfc93a039);
 388       OP (A, B, C, D, 12,  6, (md5_uint32) 0x655b59c3);
 389       OP (D, A, B, C,  3, 10, (md5_uint32) 0x8f0ccc92);
 390       OP (C, D, A, B, 10, 15, (md5_uint32) 0xffeff47d);
 391       OP (B, C, D, A,  1, 21, (md5_uint32) 0x85845dd1);
 392       OP (A, B, C, D,  8,  6, (md5_uint32) 0x6fa87e4f);
 393       OP (D, A, B, C, 15, 10, (md5_uint32) 0xfe2ce6e0);
 394       OP (C, D, A, B,  6, 15, (md5_uint32) 0xa3014314);
 395       OP (B, C, D, A, 13, 21, (md5_uint32) 0x4e0811a1);
 396       OP (A, B, C, D,  4,  6, (md5_uint32) 0xf7537e82);
 397       OP (D, A, B, C, 11, 10, (md5_uint32) 0xbd3af235);
 398       OP (C, D, A, B,  2, 15, (md5_uint32) 0x2ad7d2bb);
 399       OP (B, C, D, A,  9, 21, (md5_uint32) 0xeb86d391);
 400
 401       /* Add the starting values of the context.  */
 402       A += A_save;
 403       B += B_save;
 404       C += C_save;
 405       D += D_save;
 406     }
 407
 408   /* Put checksum in context given as argument.  */
 409   ctx->A = A;
 410   ctx->B = B;
 411   ctx->C = C;
 412   ctx->D = D;
 413 }