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             md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
 238             buffer = (const char *) buffer + 64;
 239             len -= 64;
 240           }
 241       else
 242 #endif
 243       md5_process_block (buffer, len & ~63, ctx);
 244       buffer = (const void *) ((const char *) buffer + (len & ~63));
 245       len &= 63;
 246     }
 247
 248   /* Move remaining bytes in internal buffer.  */
 249   if (len > 0)
 250     {
 251       memcpy (ctx->buffer, buffer, len);
 252       ctx->buflen = len;
 253     }
 254 }
 255
 256
 257 /* These are the four functions used in the four steps of the MD5 algorithm
 258    and defined in the RFC 1321.  The first function is a little bit optimized
 259    (as found in Colin Plumbs public domain implementation).  */
 260 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
 261 #define FF(b, c, d) (d ^ (b & (c ^ d)))
 262 #define FG(b, c, d) FF (d, b, c)
 263 #define FH(b, c, d) (b ^ c ^ d)
 264 #define FI(b, c, d) (c ^ (b | ~d))
 265
 266 /* Process LEN bytes of BUFFER, accumulating context into CTX.
 267    It is assumed that LEN % 64 == 0.  */
 268
 269 void
 270 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
 271 {
 272   md5_uint32 correct_words[16];
 273   const md5_uint32 *words = (const md5_uint32 *) buffer;
 274   size_t nwords = len / sizeof (md5_uint32);
 275   const md5_uint32 *endp = words + nwords;
 276   md5_uint32 A = ctx->A;
 277   md5_uint32 B = ctx->B;
 278   md5_uint32 C = ctx->C;
 279   md5_uint32 D = ctx->D;
 280
 281   /* First increment the byte count.  RFC 1321 specifies the possible
 282      length of the file up to 2^64 bits.  Here we only compute the
 283      number of bytes.  Do a double word increment.  */
 284   ctx->total[0] += len;
 285   if (ctx->total[0] < len)
 286     ++ctx->total[1];
 287
 288   /* Process all bytes in the buffer with 64 bytes in each round of
 289      the loop.  */
 290   while (words < endp)
 291     {
 292       md5_uint32 *cwp = correct_words;
 293       md5_uint32 A_save = A;
 294       md5_uint32 B_save = B;
 295       md5_uint32 C_save = C;
 296       md5_uint32 D_save = D;
 297
 298       /* First round: using the given function, the context and a constant
 299          the next context is computed.  Because the algorithms processing
 300          unit is a 32-bit word and it is determined to work on words in
 301          little endian byte order we perhaps have to change the byte order
 302          before the computation.  To reduce the work for the next steps
 303          we store the swapped words in the array CORRECT_WORDS.  */
 304
 305 #define OP(a, b, c, d, s, T)                                            \
 306       do                                                                \
 307         {                                                               \
 308           a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;             \
 309           ++words;                                                      \
 310           CYCLIC (a, s);                                                \
 311           a += b;                                                       \
 312         }                                                               \
 313       while (0)
 314
 315       /* It is unfortunate that C does not provide an operator for
 316          cyclic rotation.  Hope the C compiler is smart enough.  */
 317 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
 318
 319       /* Before we start, one word to the strange constants.
 320          They are defined in RFC 1321 as
 321
 322          T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
 323        */
 324
 325       /* Round 1.  */
 326       OP (A, B, C, D,  7, (md5_uint32) 0xd76aa478);
 327       OP (D, A, B, C, 12, (md5_uint32) 0xe8c7b756);
 328       OP (C, D, A, B, 17, (md5_uint32) 0x242070db);
 329       OP (B, C, D, A, 22, (md5_uint32) 0xc1bdceee);
 330       OP (A, B, C, D,  7, (md5_uint32) 0xf57c0faf);
 331       OP (D, A, B, C, 12, (md5_uint32) 0x4787c62a);
 332       OP (C, D, A, B, 17, (md5_uint32) 0xa8304613);
 333       OP (B, C, D, A, 22, (md5_uint32) 0xfd469501);
 334       OP (A, B, C, D,  7, (md5_uint32) 0x698098d8);
 335       OP (D, A, B, C, 12, (md5_uint32) 0x8b44f7af);
 336       OP (C, D, A, B, 17, (md5_uint32) 0xffff5bb1);
 337       OP (B, C, D, A, 22, (md5_uint32) 0x895cd7be);
 338       OP (A, B, C, D,  7, (md5_uint32) 0x6b901122);
 339       OP (D, A, B, C, 12, (md5_uint32) 0xfd987193);
 340       OP (C, D, A, B, 17, (md5_uint32) 0xa679438e);
 341       OP (B, C, D, A, 22, (md5_uint32) 0x49b40821);
 342
 343       /* For the second to fourth round we have the possibly swapped words
 344          in CORRECT_WORDS.  Redefine the macro to take an additional first
 345          argument specifying the function to use.  */
 346 #undef OP
 347 #define OP(a, b, c, d, k, s, T)                                         \
 348       do                                                                \
 349         {                                                               \
 350           a += FX (b, c, d) + correct_words[k] + T;                     \
 351           CYCLIC (a, s);                                                \
 352           a += b;                                                       \
 353         }                                                               \
 354       while (0)
 355
 356 #define FX(b, c, d) FG (b, c, d)
 357
 358       /* Round 2.  */
 359       OP (A, B, C, D,  1,  5, (md5_uint32) 0xf61e2562);
 360       OP (D, A, B, C,  6,  9, (md5_uint32) 0xc040b340);
 361       OP (C, D, A, B, 11, 14, (md5_uint32) 0x265e5a51);
 362       OP (B, C, D, A,  0, 20, (md5_uint32) 0xe9b6c7aa);
 363       OP (A, B, C, D,  5,  5, (md5_uint32) 0xd62f105d);
 364       OP (D, A, B, C, 10,  9, (md5_uint32) 0x02441453);
 365       OP (C, D, A, B, 15, 14, (md5_uint32) 0xd8a1e681);
 366       OP (B, C, D, A,  4, 20, (md5_uint32) 0xe7d3fbc8);
 367       OP (A, B, C, D,  9,  5, (md5_uint32) 0x21e1cde6);
 368       OP (D, A, B, C, 14,  9, (md5_uint32) 0xc33707d6);
 369       OP (C, D, A, B,  3, 14, (md5_uint32) 0xf4d50d87);
 370       OP (B, C, D, A,  8, 20, (md5_uint32) 0x455a14ed);
 371       OP (A, B, C, D, 13,  5, (md5_uint32) 0xa9e3e905);
 372       OP (D, A, B, C,  2,  9, (md5_uint32) 0xfcefa3f8);
 373       OP (C, D, A, B,  7, 14, (md5_uint32) 0x676f02d9);
 374       OP (B, C, D, A, 12, 20, (md5_uint32) 0x8d2a4c8a);
 375
 376 #undef FX
 377 #define FX(b, c, d) FH (b, c, d)
 378
 379       /* Round 3.  */
 380       OP (A, B, C, D,  5,  4, (md5_uint32) 0xfffa3942);
 381       OP (D, A, B, C,  8, 11, (md5_uint32) 0x8771f681);
 382       OP (C, D, A, B, 11, 16, (md5_uint32) 0x6d9d6122);
 383       OP (B, C, D, A, 14, 23, (md5_uint32) 0xfde5380c);
 384       OP (A, B, C, D,  1,  4, (md5_uint32) 0xa4beea44);
 385       OP (D, A, B, C,  4, 11, (md5_uint32) 0x4bdecfa9);
 386       OP (C, D, A, B,  7, 16, (md5_uint32) 0xf6bb4b60);
 387       OP (B, C, D, A, 10, 23, (md5_uint32) 0xbebfbc70);
 388       OP (A, B, C, D, 13,  4, (md5_uint32) 0x289b7ec6);
 389       OP (D, A, B, C,  0, 11, (md5_uint32) 0xeaa127fa);
 390       OP (C, D, A, B,  3, 16, (md5_uint32) 0xd4ef3085);
 391       OP (B, C, D, A,  6, 23, (md5_uint32) 0x04881d05);
 392       OP (A, B, C, D,  9,  4, (md5_uint32) 0xd9d4d039);
 393       OP (D, A, B, C, 12, 11, (md5_uint32) 0xe6db99e5);
 394       OP (C, D, A, B, 15, 16, (md5_uint32) 0x1fa27cf8);
 395       OP (B, C, D, A,  2, 23, (md5_uint32) 0xc4ac5665);
 396
 397 #undef FX
 398 #define FX(b, c, d) FI (b, c, d)
 399
 400       /* Round 4.  */
 401       OP (A, B, C, D,  0,  6, (md5_uint32) 0xf4292244);
 402       OP (D, A, B, C,  7, 10, (md5_uint32) 0x432aff97);
 403       OP (C, D, A, B, 14, 15, (md5_uint32) 0xab9423a7);
 404       OP (B, C, D, A,  5, 21, (md5_uint32) 0xfc93a039);
 405       OP (A, B, C, D, 12,  6, (md5_uint32) 0x655b59c3);
 406       OP (D, A, B, C,  3, 10, (md5_uint32) 0x8f0ccc92);
 407       OP (C, D, A, B, 10, 15, (md5_uint32) 0xffeff47d);
 408       OP (B, C, D, A,  1, 21, (md5_uint32) 0x85845dd1);
 409       OP (A, B, C, D,  8,  6, (md5_uint32) 0x6fa87e4f);
 410       OP (D, A, B, C, 15, 10, (md5_uint32) 0xfe2ce6e0);
 411       OP (C, D, A, B,  6, 15, (md5_uint32) 0xa3014314);
 412       OP (B, C, D, A, 13, 21, (md5_uint32) 0x4e0811a1);
 413       OP (A, B, C, D,  4,  6, (md5_uint32) 0xf7537e82);
 414       OP (D, A, B, C, 11, 10, (md5_uint32) 0xbd3af235);
 415       OP (C, D, A, B,  2, 15, (md5_uint32) 0x2ad7d2bb);
 416       OP (B, C, D, A,  9, 21, (md5_uint32) 0xeb86d391);
 417
 418       /* Add the starting values of the context.  */
 419       A += A_save;
 420       B += B_save;
 421       C += C_save;
 422       D += D_save;
 423     }
 424
 425   /* Put checksum in context given as argument.  */
 426   ctx->A = A;
 427   ctx->B = B;
 428   ctx->C = C;
 429   ctx->D = D;
 430 }