1 /* 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) 1995-2011 Red Hat, Inc. 4 This file is part of Red Hat elfutils. 5 Written by Ulrich Drepper <drepper (at) redhat.com>, 1995. 6 7 Red Hat elfutils is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by the 9 Free Software Foundation; version 2 of the License. 10 11 Red Hat elfutils is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License along 17 with Red Hat elfutils; if not, write to the Free Software Foundation, 18 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 19 20 Red Hat elfutils is an included package of the Open Invention Network. 21 An included package of the Open Invention Network is a package for which 22 Open Invention Network licensees cross-license their patents. No patent 23 license is granted, either expressly or impliedly, by designation as an 24 included package. Should you wish to participate in the Open Invention 25 Network licensing program, please visit www.openinventionnetwork.com 26 <http://www.openinventionnetwork.com>. */ 27 28 #ifdef HAVE_CONFIG_H 29 # include <config.h> 30 #endif 31 32 #include <stdlib.h> 33 #include <string.h> 34 #include <sys/types.h> 35 36 #include "md5.h" 37 #include "system.h" 38 39 #define SWAP(n) LE32 (n) 40 41 /* This array contains the bytes used to pad the buffer to the next 42 64-byte boundary. (RFC 1321, 3.1: Step 1) */ 43 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; 44 45 46 /* Initialize structure containing state of computation. 47 (RFC 1321, 3.3: Step 3) */ 48 void 49 md5_init_ctx (ctx) 50 struct md5_ctx *ctx; 51 { 52 ctx->A = 0x67452301; 53 ctx->B = 0xefcdab89; 54 ctx->C = 0x98badcfe; 55 ctx->D = 0x10325476; 56 57 ctx->total[0] = ctx->total[1] = 0; 58 ctx->buflen = 0; 59 } 60 61 /* Put result from CTX in first 16 bytes following RESBUF. The result 62 must be in little endian byte order. 63 64 IMPORTANT: On some systems it is required that RESBUF is correctly 65 aligned for a 32 bits value. */ 66 void * 67 md5_read_ctx (ctx, resbuf) 68 const struct md5_ctx *ctx; 69 void *resbuf; 70 { 71 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A); 72 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B); 73 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C); 74 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D); 75 76 return resbuf; 77 } 78 79 static void 80 le64_copy (char *dest, uint64_t x) 81 { 82 for (size_t i = 0; i < 8; ++i) 83 { 84 dest[i] = (uint8_t) x; 85 x >>= 8; 86 } 87 } 88 89 /* Process the remaining bytes in the internal buffer and the usual 90 prolog according to the standard and write the result to RESBUF. 91 92 IMPORTANT: On some systems it is required that RESBUF is correctly 93 aligned for a 32 bits value. */ 94 void * 95 md5_finish_ctx (ctx, resbuf) 96 struct md5_ctx *ctx; 97 void *resbuf; 98 { 99 /* Take yet unprocessed bytes into account. */ 100 md5_uint32 bytes = ctx->buflen; 101 size_t pad; 102 103 /* Now count remaining bytes. */ 104 ctx->total[0] += bytes; 105 if (ctx->total[0] < bytes) 106 ++ctx->total[1]; 107 108 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; 109 memcpy (&ctx->buffer[bytes], fillbuf, pad); 110 111 /* Put the 64-bit file length in *bits* at the end of the buffer. */ 112 const uint64_t bit_length = ((ctx->total[0] << 3) 113 + ((uint64_t) ((ctx->total[1] << 3) | 114 (ctx->total[0] >> 29)) << 32)); 115 le64_copy (&ctx->buffer[bytes + pad], bit_length); 116 117 /* Process last bytes. */ 118 md5_process_block (ctx->buffer, bytes + pad + 8, ctx); 119 120 return md5_read_ctx (ctx, resbuf); 121 } 122 123 124 #ifdef NEED_MD5_STREAM 125 /* Compute MD5 message digest for bytes read from STREAM. The 126 resulting message digest number will be written into the 16 bytes 127 beginning at RESBLOCK. */ 128 int 129 md5_stream (stream, resblock) 130 FILE *stream; 131 void *resblock; 132 { 133 /* Important: BLOCKSIZE must be a multiple of 64. */ 134 #define BLOCKSIZE 4096 135 struct md5_ctx ctx; 136 char buffer[BLOCKSIZE + 72]; 137 size_t sum; 138 139 /* Initialize the computation context. */ 140 md5_init_ctx (&ctx); 141 142 /* Iterate over full file contents. */ 143 while (1) 144 { 145 /* We read the file in blocks of BLOCKSIZE bytes. One call of the 146 computation function processes the whole buffer so that with the 147 next round of the loop another block can be read. */ 148 size_t n; 149 sum = 0; 150 151 /* Read block. Take care for partial reads. */ 152 do 153 { 154 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); 155 156 sum += n; 157 } 158 while (sum < BLOCKSIZE && n != 0); 159 if (n == 0 && ferror (stream)) 160 return 1; 161 162 /* If end of file is reached, end the loop. */ 163 if (n == 0) 164 break; 165 166 /* Process buffer with BLOCKSIZE bytes. Note that 167 BLOCKSIZE % 64 == 0 168 */ 169 md5_process_block (buffer, BLOCKSIZE, &ctx); 170 } 171 172 /* Add the last bytes if necessary. */ 173 if (sum > 0) 174 md5_process_bytes (buffer, sum, &ctx); 175 176 /* Construct result in desired memory. */ 177 md5_finish_ctx (&ctx, resblock); 178 return 0; 179 } 180 #endif 181 182 183 #ifdef NEED_MD5_BUFFER 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 #endif 206 207 208 void 209 md5_process_bytes (buffer, len, ctx) 210 const void *buffer; 211 size_t len; 212 struct md5_ctx *ctx; 213 { 214 /* When we already have some bits in our internal buffer concatenate 215 both inputs first. */ 216 if (ctx->buflen != 0) 217 { 218 size_t left_over = ctx->buflen; 219 size_t add = 128 - left_over > len ? len : 128 - left_over; 220 221 memcpy (&ctx->buffer[left_over], buffer, add); 222 ctx->buflen += add; 223 224 if (ctx->buflen > 64) 225 { 226 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx); 227 228 ctx->buflen &= 63; 229 /* The regions in the following copy operation cannot overlap. */ 230 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], 231 ctx->buflen); 232 } 233 234 buffer = (const char *) buffer + add; 235 len -= add; 236 } 237 238 /* Process available complete blocks. */ 239 if (len >= 64) 240 { 241 #if !_STRING_ARCH_unaligned 242 /* To check alignment gcc has an appropriate operator. Other 243 compilers don't. */ 244 # if __GNUC__ >= 2 245 # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0) 246 # else 247 # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0) 248 # endif 249 if (UNALIGNED_P (buffer)) 250 while (len > 64) 251 { 252 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx); 253 buffer = (const char *) buffer + 64; 254 len -= 64; 255 } 256 else 257 #endif 258 { 259 md5_process_block (buffer, len & ~63, ctx); 260 buffer = (const char *) buffer + (len & ~63); 261 len &= 63; 262 } 263 } 264 265 /* Move remaining bytes in internal buffer. */ 266 if (len > 0) 267 { 268 size_t left_over = ctx->buflen; 269 270 memcpy (&ctx->buffer[left_over], buffer, len); 271 left_over += len; 272 if (left_over >= 64) 273 { 274 md5_process_block (ctx->buffer, 64, ctx); 275 left_over -= 64; 276 memcpy (ctx->buffer, &ctx->buffer[64], left_over); 277 } 278 ctx->buflen = left_over; 279 } 280 } 281 282 283 /* These are the four functions used in the four steps of the MD5 algorithm 284 and defined in the RFC 1321. The first function is a little bit optimized 285 (as found in Colin Plumbs public domain implementation). */ 286 /* #define FF(b, c, d) ((b & c) | (~b & d)) */ 287 #define FF(b, c, d) (d ^ (b & (c ^ d))) 288 #define FG(b, c, d) FF (d, b, c) 289 #define FH(b, c, d) (b ^ c ^ d) 290 #define FI(b, c, d) (c ^ (b | ~d)) 291 292 /* Process LEN bytes of BUFFER, accumulating context into CTX. 293 It is assumed that LEN % 64 == 0. */ 294 295 void 296 md5_process_block (buffer, len, ctx) 297 const void *buffer; 298 size_t len; 299 struct md5_ctx *ctx; 300 { 301 md5_uint32 correct_words[16]; 302 const md5_uint32 *words = buffer; 303 size_t nwords = len / sizeof (md5_uint32); 304 const md5_uint32 *endp = words + nwords; 305 md5_uint32 A = ctx->A; 306 md5_uint32 B = ctx->B; 307 md5_uint32 C = ctx->C; 308 md5_uint32 D = ctx->D; 309 310 /* First increment the byte count. RFC 1321 specifies the possible 311 length of the file up to 2^64 bits. Here we only compute the 312 number of bytes. Do a double word increment. */ 313 ctx->total[0] += len; 314 if (ctx->total[0] < len) 315 ++ctx->total[1]; 316 317 /* Process all bytes in the buffer with 64 bytes in each round of 318 the loop. */ 319 while (words < endp) 320 { 321 md5_uint32 *cwp = correct_words; 322 md5_uint32 A_save = A; 323 md5_uint32 B_save = B; 324 md5_uint32 C_save = C; 325 md5_uint32 D_save = D; 326 327 /* First round: using the given function, the context and a constant 328 the next context is computed. Because the algorithms processing 329 unit is a 32-bit word and it is determined to work on words in 330 little endian byte order we perhaps have to change the byte order 331 before the computation. To reduce the work for the next steps 332 we store the swapped words in the array CORRECT_WORDS. */ 333 334 #define OP(a, b, c, d, s, T) \ 335 do \ 336 { \ 337 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ 338 ++words; \ 339 CYCLIC (a, s); \ 340 a += b; \ 341 } \ 342 while (0) 343 344 /* It is unfortunate that C does not provide an operator for 345 cyclic rotation. Hope the C compiler is smart enough. */ 346 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) 347 348 /* Before we start, one word to the strange constants. 349 They are defined in RFC 1321 as 350 351 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 352 */ 353 354 /* Round 1. */ 355 OP (A, B, C, D, 7, 0xd76aa478); 356 OP (D, A, B, C, 12, 0xe8c7b756); 357 OP (C, D, A, B, 17, 0x242070db); 358 OP (B, C, D, A, 22, 0xc1bdceee); 359 OP (A, B, C, D, 7, 0xf57c0faf); 360 OP (D, A, B, C, 12, 0x4787c62a); 361 OP (C, D, A, B, 17, 0xa8304613); 362 OP (B, C, D, A, 22, 0xfd469501); 363 OP (A, B, C, D, 7, 0x698098d8); 364 OP (D, A, B, C, 12, 0x8b44f7af); 365 OP (C, D, A, B, 17, 0xffff5bb1); 366 OP (B, C, D, A, 22, 0x895cd7be); 367 OP (A, B, C, D, 7, 0x6b901122); 368 OP (D, A, B, C, 12, 0xfd987193); 369 OP (C, D, A, B, 17, 0xa679438e); 370 OP (B, C, D, A, 22, 0x49b40821); 371 372 /* For the second to fourth round we have the possibly swapped words 373 in CORRECT_WORDS. Redefine the macro to take an additional first 374 argument specifying the function to use. */ 375 #undef OP 376 #define OP(f, a, b, c, d, k, s, T) \ 377 do \ 378 { \ 379 a += f (b, c, d) + correct_words[k] + T; \ 380 CYCLIC (a, s); \ 381 a += b; \ 382 } \ 383 while (0) 384 385 /* Round 2. */ 386 OP (FG, A, B, C, D, 1, 5, 0xf61e2562); 387 OP (FG, D, A, B, C, 6, 9, 0xc040b340); 388 OP (FG, C, D, A, B, 11, 14, 0x265e5a51); 389 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa); 390 OP (FG, A, B, C, D, 5, 5, 0xd62f105d); 391 OP (FG, D, A, B, C, 10, 9, 0x02441453); 392 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681); 393 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8); 394 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6); 395 OP (FG, D, A, B, C, 14, 9, 0xc33707d6); 396 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87); 397 OP (FG, B, C, D, A, 8, 20, 0x455a14ed); 398 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905); 399 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8); 400 OP (FG, C, D, A, B, 7, 14, 0x676f02d9); 401 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a); 402 403 /* Round 3. */ 404 OP (FH, A, B, C, D, 5, 4, 0xfffa3942); 405 OP (FH, D, A, B, C, 8, 11, 0x8771f681); 406 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122); 407 OP (FH, B, C, D, A, 14, 23, 0xfde5380c); 408 OP (FH, A, B, C, D, 1, 4, 0xa4beea44); 409 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9); 410 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60); 411 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70); 412 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6); 413 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa); 414 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085); 415 OP (FH, B, C, D, A, 6, 23, 0x04881d05); 416 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039); 417 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5); 418 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8); 419 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665); 420 421 /* Round 4. */ 422 OP (FI, A, B, C, D, 0, 6, 0xf4292244); 423 OP (FI, D, A, B, C, 7, 10, 0x432aff97); 424 OP (FI, C, D, A, B, 14, 15, 0xab9423a7); 425 OP (FI, B, C, D, A, 5, 21, 0xfc93a039); 426 OP (FI, A, B, C, D, 12, 6, 0x655b59c3); 427 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92); 428 OP (FI, C, D, A, B, 10, 15, 0xffeff47d); 429 OP (FI, B, C, D, A, 1, 21, 0x85845dd1); 430 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f); 431 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0); 432 OP (FI, C, D, A, B, 6, 15, 0xa3014314); 433 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1); 434 OP (FI, A, B, C, D, 4, 6, 0xf7537e82); 435 OP (FI, D, A, B, C, 11, 10, 0xbd3af235); 436 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb); 437 OP (FI, B, C, D, A, 9, 21, 0xeb86d391); 438 439 /* Add the starting values of the context. */ 440 A += A_save; 441 B += B_save; 442 C += C_save; 443 D += D_save; 444 } 445 446 /* Put checksum in context given as argument. */ 447 ctx->A = A; 448 ctx->B = B; 449 ctx->C = C; 450 ctx->D = D; 451 } 452
