ld/sha1.c

   1 /* sha1.c - Functions to compute SHA1 message digest of files or
   2    memory blocks according to the NIST specification FIPS-180-1.
   3
   4    Copyright (C) 2007 Free Software Foundation, Inc.
   5
   6    This file is part of the GNU Binutils.
   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 3, 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 Scott G. Miller
  23    Credits:
  24       Robert Klep <robert@ilse.nl>  -- Expansion function fix  */
  25
  26 #include <config.h>
  27 #include "sha1.h"
  28 #include <stddef.h>
  29 #include <string.h>
  30
  31 #if USE_UNLOCKED_IO
  32 # include "unlocked-io.h"
  33 #endif
  34
  35 #ifdef WORDS_BIGENDIAN
  36 # define SWAP(n) (n)
  37 #else
  38 # define SWAP(n) \
  39     (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
  40 #endif
  41
  42 #define BLOCKSIZE 4096
  43 #if BLOCKSIZE % 64 != 0
  44 # error "invalid BLOCKSIZE"
  45 #endif
  46
  47 /* This array contains the bytes used to pad the buffer to the next
  48    64-byte boundary.  (RFC 1321, 3.1: Step 1)  */
  49 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */ };
  50
  51
  52 /* Take a pointer to a 160 bit block of data (five 32 bit ints) and
  53    initialize it to the start constants of the SHA1 algorithm.  This
  54    must be called before using hash in the call to sha1_hash.  */
  55
  56 void
  57 sha1_init_ctx (struct sha1_ctx *ctx)
  58 {
  59   ctx->A = 0x67452301;
  60   ctx->B = 0xefcdab89;
  61   ctx->C = 0x98badcfe;
  62   ctx->D = 0x10325476;
  63   ctx->E = 0xc3d2e1f0;
  64
  65   ctx->total[0] = ctx->total[1] = 0;
  66   ctx->buflen = 0;
  67 }
  68
  69 /* Put result from CTX in first 20 bytes following RESBUF.  The result
  70    must be in little endian byte order.
  71
  72    IMPORTANT: On some systems it is required that RESBUF is correctly
  73    aligned for a 32-bit value.  */
  74
  75 void *
  76 sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf)
  77 {
  78   ((uint32_t *) resbuf)[0] = SWAP (ctx->A);
  79   ((uint32_t *) resbuf)[1] = SWAP (ctx->B);
  80   ((uint32_t *) resbuf)[2] = SWAP (ctx->C);
  81   ((uint32_t *) resbuf)[3] = SWAP (ctx->D);
  82   ((uint32_t *) resbuf)[4] = SWAP (ctx->E);
  83
  84   return resbuf;
  85 }
  86
  87 /* Process the remaining bytes in the internal buffer and the usual
  88    prolog according to the standard and write the result to RESBUF.
  89
  90    IMPORTANT: On some systems it is required that RESBUF is correctly
  91    aligned for a 32-bit value.  */
  92
  93 void *
  94 sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf)
  95 {
  96   /* Take yet unprocessed bytes into account.  */
  97   uint32_t bytes = ctx->buflen;
  98   size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
  99
 100   /* Now count remaining bytes.  */
 101   ctx->total[0] += bytes;
 102   if (ctx->total[0] < bytes)
 103     ++ctx->total[1];
 104
 105   /* Put the 64-bit file length in *bits* at the end of the buffer.  */
 106   ctx->buffer[size - 2] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
 107   ctx->buffer[size - 1] = SWAP (ctx->total[0] << 3);
 108
 109   memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
 110
 111   /* Process last bytes.  */
 112   sha1_process_block (ctx->buffer, size * 4, ctx);
 113
 114   return sha1_read_ctx (ctx, resbuf);
 115 }
 116
 117 /* Compute SHA1 message digest for bytes read from STREAM.  The
 118    resulting message digest number will be written into the 16 bytes
 119    beginning at RESBLOCK.  */
 120
 121 int
 122 sha1_stream (FILE *stream, void *resblock)
 123 {
 124   struct sha1_ctx ctx;
 125   char buffer[BLOCKSIZE + 72];
 126   size_t sum;
 127
 128   /* Initialize the computation context.  */
 129   sha1_init_ctx (&ctx);
 130
 131   /* Iterate over full file contents.  */
 132   while (1)
 133     {
 134       /* We read the file in blocks of BLOCKSIZE bytes.  One call of the
 135          computation function processes the whole buffer so that with the
 136          next round of the loop another block can be read.  */
 137       size_t n;
 138       sum = 0;
 139
 140       /* Read block.  Take care for partial reads.  */
 141       while (1)
 142         {
 143           n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
 144
 145           sum += n;
 146
 147           if (sum == BLOCKSIZE)
 148             break;
 149
 150           if (n == 0)
 151             {
 152               /* Check for the error flag IFF N == 0, so that we don't
 153                  exit the loop after a partial read due to e.g., EAGAIN
 154                  or EWOULDBLOCK.  */
 155               if (ferror (stream))
 156                 return 1;
 157               goto process_partial_block;
 158             }
 159
 160           /* We've read at least one byte, so ignore errors.  But always
 161              check for EOF, since feof may be true even though N > 0.
 162              Otherwise, we could end up calling fread after EOF.  */
 163           if (feof (stream))
 164             goto process_partial_block;
 165         }
 166
 167       /* Process buffer with BLOCKSIZE bytes.  Note that
 168                         BLOCKSIZE % 64 == 0.  */
 169       sha1_process_block (buffer, BLOCKSIZE, &ctx);
 170     }
 171
 172  process_partial_block:;
 173
 174   /* Process any remaining bytes.  */
 175   if (sum > 0)
 176     sha1_process_bytes (buffer, sum, &ctx);
 177
 178   /* Construct result in desired memory.  */
 179   sha1_finish_ctx (&ctx, resblock);
 180   return 0;
 181 }
 182
 183 /* Compute SHA1 message digest for LEN bytes beginning at BUFFER.  The
 184    result is always in little endian byte order, so that a byte-wise
 185    output yields to the wanted ASCII representation of the message
 186    digest.  */
 187
 188 void *
 189 sha1_buffer (const char *buffer, size_t len, void *resblock)
 190 {
 191   struct sha1_ctx ctx;
 192
 193   /* Initialize the computation context.  */
 194   sha1_init_ctx (&ctx);
 195
 196   /* Process whole buffer but last len % 64 bytes.  */
 197   sha1_process_bytes (buffer, len, &ctx);
 198
 199   /* Put result in desired memory area.  */
 200   return sha1_finish_ctx (&ctx, resblock);
 201 }
 202
 203 void
 204 sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx)
 205 {
 206   /* When we already have some bits in our internal buffer concatenate
 207      both inputs first.  */
 208   if (ctx->buflen != 0)
 209     {
 210       size_t left_over = ctx->buflen;
 211       size_t add = 128 - left_over > len ? len : 128 - left_over;
 212
 213       memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
 214       ctx->buflen += add;
 215
 216       if (ctx->buflen > 64)
 217         {
 218           sha1_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
 219
 220           ctx->buflen &= 63;
 221           /* The regions in the following copy operation cannot overlap.  */
 222           memcpy (ctx->buffer,
 223                   &((char *) ctx->buffer)[(left_over + add) & ~63],
 224                   ctx->buflen);
 225         }
 226
 227       buffer = (const char *) buffer + add;
 228       len -= add;
 229     }
 230
 231   /* Process available complete blocks.  */
 232   if (len >= 64)
 233     {
 234 #if !_STRING_ARCH_unaligned
 235 # define alignof(type)  offsetof (struct { char c; type x; }, x)
 236 # define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0)
 237       if (UNALIGNED_P (buffer))
 238         while (len > 64)
 239           {
 240             sha1_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
 241             buffer = (const char *) buffer + 64;
 242             len -= 64;
 243           }
 244       else
 245 #endif
 246         {
 247           sha1_process_block (buffer, len & ~63, ctx);
 248           buffer = (const char *) buffer + (len & ~63);
 249           len &= 63;
 250         }
 251     }
 252
 253   /* Move remaining bytes in internal buffer.  */
 254   if (len > 0)
 255     {
 256       size_t left_over = ctx->buflen;
 257
 258       memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
 259       left_over += len;
 260       if (left_over >= 64)
 261         {
 262           sha1_process_block (ctx->buffer, 64, ctx);
 263           left_over -= 64;
 264           memcpy (ctx->buffer, &ctx->buffer[16], left_over);
 265         }
 266       ctx->buflen = left_over;
 267     }
 268 }
 269
 270 /* --- Code below is the primary difference between md5.c and sha1.c --- */
 271
 272 /* SHA1 round constants.  */
 273 #define K1 0x5a827999
 274 #define K2 0x6ed9eba1
 275 #define K3 0x8f1bbcdc
 276 #define K4 0xca62c1d6
 277
 278 /* Round functions.  Note that F2 is the same as F4.  */
 279 #define F1(B,C,D) (D ^ (B & (C ^ D)))
 280 #define F2(B,C,D) (B ^ C ^ D)
 281 #define F3(B,C,D) ((B & C) | (D & (B | C)))
 282 #define F4(B,C,D) (B ^ C ^ D)
 283
 284 /* Process LEN bytes of BUFFER, accumulating context into CTX.
 285    It is assumed that LEN % 64 == 0.
 286    Most of this code comes from GnuPG's cipher/sha1.c.  */
 287
 288 void
 289 sha1_process_block (const void *buffer, size_t len, struct sha1_ctx *ctx)
 290 {
 291   const uint32_t *words = buffer;
 292   size_t nwords = len / sizeof (uint32_t);
 293   const uint32_t *endp = words + nwords;
 294   uint32_t x[16];
 295   uint32_t a = ctx->A;
 296   uint32_t b = ctx->B;
 297   uint32_t c = ctx->C;
 298   uint32_t d = ctx->D;
 299   uint32_t e = ctx->E;
 300
 301   /* First increment the byte count.  RFC 1321 specifies the possible
 302      length of the file up to 2^64 bits.  Here we only compute the
 303      number of bytes.  Do a double word increment.  */
 304   ctx->total[0] += len;
 305   if (ctx->total[0] < len)
 306     ++ctx->total[1];
 307
 308 #define rol(x, n) (((x) << (n)) | ((uint32_t) (x) >> (32 - (n))))
 309
 310 #define M(I) (tm = x[I & 0x0f]       ^ x[(I - 14) & 0x0f] \
 311                  ^ x[(I - 8) & 0x0f] ^ x[(I - 3) & 0x0f]  \
 312                , (x[I & 0x0f] = rol (tm, 1)))
 313
 314 #define R(A,B,C,D,E,F,K,M)      \
 315   do                            \
 316     {                           \
 317       E += rol (A, 5)           \
 318         + F (B, C, D)           \
 319         + K                     \
 320         + M;                    \
 321       B = rol (B, 30);          \
 322     }                           \
 323   while (0)
 324
 325   while (words < endp)
 326     {
 327       uint32_t tm;
 328       int t;
 329
 330       for (t = 0; t < 16; t++)
 331         {
 332           x[t] = SWAP (*words);
 333           words++;
 334         }
 335
 336       R (a, b, c, d, e, F1, K1, x[ 0]);
 337       R (e, a, b, c, d, F1, K1, x[ 1]);
 338       R (d, e, a, b, c, F1, K1, x[ 2]);
 339       R (c, d, e, a, b, F1, K1, x[ 3]);
 340       R (b, c, d, e, a, F1, K1, x[ 4]);
 341       R (a, b, c, d, e, F1, K1, x[ 5]);
 342       R (e, a, b, c, d, F1, K1, x[ 6]);
 343       R (d, e, a, b, c, F1, K1, x[ 7]);
 344       R (c, d, e, a, b, F1, K1, x[ 8]);
 345       R (b, c, d, e, a, F1, K1, x[ 9]);
 346       R (a, b, c, d, e, F1, K1, x[10]);
 347       R (e, a, b, c, d, F1, K1, x[11]);
 348       R (d, e, a, b, c, F1, K1, x[12]);
 349       R (c, d, e, a, b, F1, K1, x[13]);
 350       R (b, c, d, e, a, F1, K1, x[14]);
 351       R (a, b, c, d, e, F1, K1, x[15]);
 352       R (e, a, b, c, d, F1, K1, M(16));
 353       R (d, e, a, b, c, F1, K1, M(17));
 354       R (c, d, e, a, b, F1, K1, M(18));
 355       R (b, c, d, e, a, F1, K1, M(19));
 356       R (a, b, c, d, e, F2, K2, M(20));
 357       R (e, a, b, c, d, F2, K2, M(21));
 358       R (d, e, a, b, c, F2, K2, M(22));
 359       R (c, d, e, a, b, F2, K2, M(23));
 360       R (b, c, d, e, a, F2, K2, M(24));
 361       R (a, b, c, d, e, F2, K2, M(25));
 362       R (e, a, b, c, d, F2, K2, M(26));
 363       R (d, e, a, b, c, F2, K2, M(27));
 364       R (c, d, e, a, b, F2, K2, M(28));
 365       R (b, c, d, e, a, F2, K2, M(29));
 366       R (a, b, c, d, e, F2, K2, M(30));
 367       R (e, a, b, c, d, F2, K2, M(31));
 368       R (d, e, a, b, c, F2, K2, M(32));
 369       R (c, d, e, a, b, F2, K2, M(33));
 370       R (b, c, d, e, a, F2, K2, M(34));
 371       R (a, b, c, d, e, F2, K2, M(35));
 372       R (e, a, b, c, d, F2, K2, M(36));
 373       R (d, e, a, b, c, F2, K2, M(37));
 374       R (c, d, e, a, b, F2, K2, M(38));
 375       R (b, c, d, e, a, F2, K2, M(39));
 376       R (a, b, c, d, e, F3, K3, M(40));
 377       R (e, a, b, c, d, F3, K3, M(41));
 378       R (d, e, a, b, c, F3, K3, M(42));
 379       R (c, d, e, a, b, F3, K3, M(43));
 380       R (b, c, d, e, a, F3, K3, M(44));
 381       R (a, b, c, d, e, F3, K3, M(45));
 382       R (e, a, b, c, d, F3, K3, M(46));
 383       R (d, e, a, b, c, F3, K3, M(47));
 384       R (c, d, e, a, b, F3, K3, M(48));
 385       R (b, c, d, e, a, F3, K3, M(49));
 386       R (a, b, c, d, e, F3, K3, M(50));
 387       R (e, a, b, c, d, F3, K3, M(51));
 388       R (d, e, a, b, c, F3, K3, M(52));
 389       R (c, d, e, a, b, F3, K3, M(53));
 390       R (b, c, d, e, a, F3, K3, M(54));
 391       R (a, b, c, d, e, F3, K3, M(55));
 392       R (e, a, b, c, d, F3, K3, M(56));
 393       R (d, e, a, b, c, F3, K3, M(57));
 394       R (c, d, e, a, b, F3, K3, M(58));
 395       R (b, c, d, e, a, F3, K3, M(59));
 396       R (a, b, c, d, e, F4, K4, M(60));
 397       R (e, a, b, c, d, F4, K4, M(61));
 398       R (d, e, a, b, c, F4, K4, M(62));
 399       R (c, d, e, a, b, F4, K4, M(63));
 400       R (b, c, d, e, a, F4, K4, M(64));
 401       R (a, b, c, d, e, F4, K4, M(65));
 402       R (e, a, b, c, d, F4, K4, M(66));
 403       R (d, e, a, b, c, F4, K4, M(67));
 404       R (c, d, e, a, b, F4, K4, M(68));
 405       R (b, c, d, e, a, F4, K4, M(69));
 406       R (a, b, c, d, e, F4, K4, M(70));
 407       R (e, a, b, c, d, F4, K4, M(71));
 408       R (d, e, a, b, c, F4, K4, M(72));
 409       R (c, d, e, a, b, F4, K4, M(73));
 410       R (b, c, d, e, a, F4, K4, M(74));
 411       R (a, b, c, d, e, F4, K4, M(75));
 412       R (e, a, b, c, d, F4, K4, M(76));
 413       R (d, e, a, b, c, F4, K4, M(77));
 414       R (c, d, e, a, b, F4, K4, M(78));
 415       R (b, c, d, e, a, F4, K4, M(79));
 416
 417       a = ctx->A += a;
 418       b = ctx->B += b;
 419       c = ctx->C += c;
 420       d = ctx->D += d;
 421       e = ctx->E += e;
 422     }
 423 }