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, 2011 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: RESBUF may not be aligned as strongly as MD5_UNIT32 so we 80 put things in a local (aligned) buffer first, then memcpy into RESBUF. */ 81 void * 82 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf) 83 { 84 md5_uint32 buffer[4]; 85 86 buffer[0] = SWAP (ctx->A); 87 buffer[1] = SWAP (ctx->B); 88 buffer[2] = SWAP (ctx->C); 89 buffer[3] = SWAP (ctx->D); 90 91 memcpy (resbuf, buffer, 16); 92 93 return resbuf; 94 } 95 96 /* Process the remaining bytes in the internal buffer and the usual 97 prolog according to the standard and write the result to RESBUF. 98 99 IMPORTANT: On some systems it is required that RESBUF is correctly 100 aligned for a 32 bits value. */ 101 void * 102 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf) 103 { 104 /* Take yet unprocessed bytes into account. */ 105 md5_uint32 bytes = ctx->buflen; 106 size_t pad; 107 108 /* Now count remaining bytes. */ 109 ctx->total[0] += bytes; 110 if (ctx->total[0] < bytes) 111 ++ctx->total[1]; 112 113 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; 114 memcpy (&ctx->buffer[bytes], fillbuf, pad); 115 116 /* Put the 64-bit file length in *bits* at the end of the buffer. */ 117 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3); 118 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) | 119 (ctx->total[0] >> 29)); 120 121 /* Process last bytes. */ 122 md5_process_block (ctx->buffer, bytes + pad + 8, ctx); 123 124 return md5_read_ctx (ctx, resbuf); 125 } 126 127 /* Compute MD5 message digest for bytes read from STREAM. The 128 resulting message digest number will be written into the 16 bytes 129 beginning at RESBLOCK. */ 130 int 131 md5_stream (FILE *stream, 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 } 180 181 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The 182 result is always in little endian byte order, so that a byte-wise 183 output yields to the wanted ASCII representation of the message 184 digest. */ 185 void * 186 md5_buffer (const char *buffer, size_t len, void *resblock) 187 { 188 struct md5_ctx ctx; 189 190 /* Initialize the computation context. */ 191 md5_init_ctx (&ctx); 192 193 /* Process whole buffer but last len % 64 bytes. */ 194 md5_process_bytes (buffer, len, &ctx); 195 196 /* Put result in desired memory area. */ 197 return md5_finish_ctx (&ctx, resblock); 198 } 199 200 201 void 202 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx) 203 { 204 /* When we already have some bits in our internal buffer concatenate 205 both inputs first. */ 206 if (ctx->buflen != 0) 207 { 208 size_t left_over = ctx->buflen; 209 size_t add = 128 - left_over > len ? len : 128 - left_over; 210 211 memcpy (&ctx->buffer[left_over], buffer, add); 212 ctx->buflen += add; 213 214 if (left_over + add > 64) 215 { 216 md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx); 217 /* The regions in the following copy operation cannot overlap. */ 218 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], 219 (left_over + add) & 63); 220 ctx->buflen = (left_over + add) & 63; 221 } 222 223 buffer = (const void *) ((const char *) buffer + add); 224 len -= add; 225 } 226 227 /* Process available complete blocks. */ 228 if (len > 64) 229 { 230 #if !_STRING_ARCH_unaligned 231 /* To check alignment gcc has an appropriate operator. Other 232 compilers don't. */ 233 # if __GNUC__ >= 2 234 # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0) 235 # else 236 # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0) 237 # endif 238 if (UNALIGNED_P (buffer)) 239 while (len > 64) 240 { 241 memcpy (ctx->buffer, buffer, 64); 242 md5_process_block (ctx->buffer, 64, ctx); 243 buffer = (const char *) buffer + 64; 244 len -= 64; 245 } 246 else 247 #endif 248 { 249 md5_process_block (buffer, len & ~63, ctx); 250 buffer = (const void *) ((const char *) buffer + (len & ~63)); 251 len &= 63; 252 } 253 } 254 255 /* Move remaining bytes in internal buffer. */ 256 if (len > 0) 257 { 258 memcpy (ctx->buffer, buffer, len); 259 ctx->buflen = len; 260 } 261 } 262 263 264 /* These are the four functions used in the four steps of the MD5 algorithm 265 and defined in the RFC 1321. The first function is a little bit optimized 266 (as found in Colin Plumbs public domain implementation). */ 267 /* #define FF(b, c, d) ((b & c) | (~b & d)) */ 268 #define FF(b, c, d) (d ^ (b & (c ^ d))) 269 #define FG(b, c, d) FF (d, b, c) 270 #define FH(b, c, d) (b ^ c ^ d) 271 #define FI(b, c, d) (c ^ (b | ~d)) 272 273 /* Process LEN bytes of BUFFER, accumulating context into CTX. 274 It is assumed that LEN % 64 == 0. */ 275 276 void 277 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx) 278 { 279 md5_uint32 correct_words[16]; 280 const md5_uint32 *words = (const md5_uint32 *) buffer; 281 size_t nwords = len / sizeof (md5_uint32); 282 const md5_uint32 *endp = words + nwords; 283 md5_uint32 A = ctx->A; 284 md5_uint32 B = ctx->B; 285 md5_uint32 C = ctx->C; 286 md5_uint32 D = ctx->D; 287 288 /* First increment the byte count. RFC 1321 specifies the possible 289 length of the file up to 2^64 bits. Here we only compute the 290 number of bytes. Do a double word increment. */ 291 ctx->total[0] += len; 292 if (ctx->total[0] < len) 293 ++ctx->total[1]; 294 295 /* Process all bytes in the buffer with 64 bytes in each round of 296 the loop. */ 297 while (words < endp) 298 { 299 md5_uint32 *cwp = correct_words; 300 md5_uint32 A_save = A; 301 md5_uint32 B_save = B; 302 md5_uint32 C_save = C; 303 md5_uint32 D_save = D; 304 305 /* First round: using the given function, the context and a constant 306 the next context is computed. Because the algorithms processing 307 unit is a 32-bit word and it is determined to work on words in 308 little endian byte order we perhaps have to change the byte order 309 before the computation. To reduce the work for the next steps 310 we store the swapped words in the array CORRECT_WORDS. */ 311 312 #define OP(a, b, c, d, s, T) \ 313 do \ 314 { \ 315 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ 316 ++words; \ 317 CYCLIC (a, s); \ 318 a += b; \ 319 } \ 320 while (0) 321 322 /* It is unfortunate that C does not provide an operator for 323 cyclic rotation. Hope the C compiler is smart enough. */ 324 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) 325 326 /* Before we start, one word to the strange constants. 327 They are defined in RFC 1321 as 328 329 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 330 */ 331 332 /* Round 1. */ 333 OP (A, B, C, D, 7, (md5_uint32) 0xd76aa478); 334 OP (D, A, B, C, 12, (md5_uint32) 0xe8c7b756); 335 OP (C, D, A, B, 17, (md5_uint32) 0x242070db); 336 OP (B, C, D, A, 22, (md5_uint32) 0xc1bdceee); 337 OP (A, B, C, D, 7, (md5_uint32) 0xf57c0faf); 338 OP (D, A, B, C, 12, (md5_uint32) 0x4787c62a); 339 OP (C, D, A, B, 17, (md5_uint32) 0xa8304613); 340 OP (B, C, D, A, 22, (md5_uint32) 0xfd469501); 341 OP (A, B, C, D, 7, (md5_uint32) 0x698098d8); 342 OP (D, A, B, C, 12, (md5_uint32) 0x8b44f7af); 343 OP (C, D, A, B, 17, (md5_uint32) 0xffff5bb1); 344 OP (B, C, D, A, 22, (md5_uint32) 0x895cd7be); 345 OP (A, B, C, D, 7, (md5_uint32) 0x6b901122); 346 OP (D, A, B, C, 12, (md5_uint32) 0xfd987193); 347 OP (C, D, A, B, 17, (md5_uint32) 0xa679438e); 348 OP (B, C, D, A, 22, (md5_uint32) 0x49b40821); 349 350 /* For the second to fourth round we have the possibly swapped words 351 in CORRECT_WORDS. Redefine the macro to take an additional first 352 argument specifying the function to use. */ 353 #undef OP 354 #define OP(a, b, c, d, k, s, T) \ 355 do \ 356 { \ 357 a += FX (b, c, d) + correct_words[k] + T; \ 358 CYCLIC (a, s); \ 359 a += b; \ 360 } \ 361 while (0) 362 363 #define FX(b, c, d) FG (b, c, d) 364 365 /* Round 2. */ 366 OP (A, B, C, D, 1, 5, (md5_uint32) 0xf61e2562); 367 OP (D, A, B, C, 6, 9, (md5_uint32) 0xc040b340); 368 OP (C, D, A, B, 11, 14, (md5_uint32) 0x265e5a51); 369 OP (B, C, D, A, 0, 20, (md5_uint32) 0xe9b6c7aa); 370 OP (A, B, C, D, 5, 5, (md5_uint32) 0xd62f105d); 371 OP (D, A, B, C, 10, 9, (md5_uint32) 0x02441453); 372 OP (C, D, A, B, 15, 14, (md5_uint32) 0xd8a1e681); 373 OP (B, C, D, A, 4, 20, (md5_uint32) 0xe7d3fbc8); 374 OP (A, B, C, D, 9, 5, (md5_uint32) 0x21e1cde6); 375 OP (D, A, B, C, 14, 9, (md5_uint32) 0xc33707d6); 376 OP (C, D, A, B, 3, 14, (md5_uint32) 0xf4d50d87); 377 OP (B, C, D, A, 8, 20, (md5_uint32) 0x455a14ed); 378 OP (A, B, C, D, 13, 5, (md5_uint32) 0xa9e3e905); 379 OP (D, A, B, C, 2, 9, (md5_uint32) 0xfcefa3f8); 380 OP (C, D, A, B, 7, 14, (md5_uint32) 0x676f02d9); 381 OP (B, C, D, A, 12, 20, (md5_uint32) 0x8d2a4c8a); 382 383 #undef FX 384 #define FX(b, c, d) FH (b, c, d) 385 386 /* Round 3. */ 387 OP (A, B, C, D, 5, 4, (md5_uint32) 0xfffa3942); 388 OP (D, A, B, C, 8, 11, (md5_uint32) 0x8771f681); 389 OP (C, D, A, B, 11, 16, (md5_uint32) 0x6d9d6122); 390 OP (B, C, D, A, 14, 23, (md5_uint32) 0xfde5380c); 391 OP (A, B, C, D, 1, 4, (md5_uint32) 0xa4beea44); 392 OP (D, A, B, C, 4, 11, (md5_uint32) 0x4bdecfa9); 393 OP (C, D, A, B, 7, 16, (md5_uint32) 0xf6bb4b60); 394 OP (B, C, D, A, 10, 23, (md5_uint32) 0xbebfbc70); 395 OP (A, B, C, D, 13, 4, (md5_uint32) 0x289b7ec6); 396 OP (D, A, B, C, 0, 11, (md5_uint32) 0xeaa127fa); 397 OP (C, D, A, B, 3, 16, (md5_uint32) 0xd4ef3085); 398 OP (B, C, D, A, 6, 23, (md5_uint32) 0x04881d05); 399 OP (A, B, C, D, 9, 4, (md5_uint32) 0xd9d4d039); 400 OP (D, A, B, C, 12, 11, (md5_uint32) 0xe6db99e5); 401 OP (C, D, A, B, 15, 16, (md5_uint32) 0x1fa27cf8); 402 OP (B, C, D, A, 2, 23, (md5_uint32) 0xc4ac5665); 403 404 #undef FX 405 #define FX(b, c, d) FI (b, c, d) 406 407 /* Round 4. */ 408 OP (A, B, C, D, 0, 6, (md5_uint32) 0xf4292244); 409 OP (D, A, B, C, 7, 10, (md5_uint32) 0x432aff97); 410 OP (C, D, A, B, 14, 15, (md5_uint32) 0xab9423a7); 411 OP (B, C, D, A, 5, 21, (md5_uint32) 0xfc93a039); 412 OP (A, B, C, D, 12, 6, (md5_uint32) 0x655b59c3); 413 OP (D, A, B, C, 3, 10, (md5_uint32) 0x8f0ccc92); 414 OP (C, D, A, B, 10, 15, (md5_uint32) 0xffeff47d); 415 OP (B, C, D, A, 1, 21, (md5_uint32) 0x85845dd1); 416 OP (A, B, C, D, 8, 6, (md5_uint32) 0x6fa87e4f); 417 OP (D, A, B, C, 15, 10, (md5_uint32) 0xfe2ce6e0); 418 OP (C, D, A, B, 6, 15, (md5_uint32) 0xa3014314); 419 OP (B, C, D, A, 13, 21, (md5_uint32) 0x4e0811a1); 420 OP (A, B, C, D, 4, 6, (md5_uint32) 0xf7537e82); 421 OP (D, A, B, C, 11, 10, (md5_uint32) 0xbd3af235); 422 OP (C, D, A, B, 2, 15, (md5_uint32) 0x2ad7d2bb); 423 OP (B, C, D, A, 9, 21, (md5_uint32) 0xeb86d391); 424 425 /* Add the starting values of the context. */ 426 A += A_save; 427 B += B_save; 428 C += C_save; 429 D += D_save; 430 } 431 432 /* Put checksum in context given as argument. */ 433 ctx->A = A; 434 ctx->B = B; 435 ctx->C = C; 436 ctx->D = D; 437 } 438