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 md5_uint32 swap_bytes; 107 size_t pad; 108 109 /* Now count remaining bytes. */ 110 ctx->total[0] += bytes; 111 if (ctx->total[0] < bytes) 112 ++ctx->total[1]; 113 114 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; 115 memcpy (&ctx->buffer[bytes], fillbuf, pad); 116 117 /* Put the 64-bit file length in *bits* at the end of the buffer. 118 Use memcpy to avoid aliasing problems. On most systems, this 119 will be optimized away to the same code. */ 120 swap_bytes = SWAP (ctx->total[0] << 3); 121 memcpy (&ctx->buffer[bytes + pad], &swap_bytes, sizeof (swap_bytes)); 122 swap_bytes = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29)); 123 memcpy (&ctx->buffer[bytes + pad + 4], &swap_bytes, sizeof (swap_bytes)); 124 125 /* Process last bytes. */ 126 md5_process_block (ctx->buffer, bytes + pad + 8, ctx); 127 128 return md5_read_ctx (ctx, resbuf); 129 } 130 131 /* Compute MD5 message digest for bytes read from STREAM. The 132 resulting message digest number will be written into the 16 bytes 133 beginning at RESBLOCK. */ 134 int 135 md5_stream (FILE *stream, void *resblock) 136 { 137 /* Important: BLOCKSIZE must be a multiple of 64. */ 138 #define BLOCKSIZE 4096 139 struct md5_ctx ctx; 140 char buffer[BLOCKSIZE + 72]; 141 size_t sum; 142 143 /* Initialize the computation context. */ 144 md5_init_ctx (&ctx); 145 146 /* Iterate over full file contents. */ 147 while (1) 148 { 149 /* We read the file in blocks of BLOCKSIZE bytes. One call of the 150 computation function processes the whole buffer so that with the 151 next round of the loop another block can be read. */ 152 size_t n; 153 sum = 0; 154 155 /* Read block. Take care for partial reads. */ 156 do 157 { 158 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); 159 160 sum += n; 161 } 162 while (sum < BLOCKSIZE && n != 0); 163 if (n == 0 && ferror (stream)) 164 return 1; 165 166 /* If end of file is reached, end the loop. */ 167 if (n == 0) 168 break; 169 170 /* Process buffer with BLOCKSIZE bytes. Note that 171 BLOCKSIZE % 64 == 0 172 */ 173 md5_process_block (buffer, BLOCKSIZE, &ctx); 174 } 175 176 /* Add the last bytes if necessary. */ 177 if (sum > 0) 178 md5_process_bytes (buffer, sum, &ctx); 179 180 /* Construct result in desired memory. */ 181 md5_finish_ctx (&ctx, resblock); 182 return 0; 183 } 184 185 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The 186 result is always in little endian byte order, so that a byte-wise 187 output yields to the wanted ASCII representation of the message 188 digest. */ 189 void * 190 md5_buffer (const char *buffer, size_t len, void *resblock) 191 { 192 struct md5_ctx ctx; 193 194 /* Initialize the computation context. */ 195 md5_init_ctx (&ctx); 196 197 /* Process whole buffer but last len % 64 bytes. */ 198 md5_process_bytes (buffer, len, &ctx); 199 200 /* Put result in desired memory area. */ 201 return md5_finish_ctx (&ctx, resblock); 202 } 203 204 205 void 206 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx) 207 { 208 /* When we already have some bits in our internal buffer concatenate 209 both inputs first. */ 210 if (ctx->buflen != 0) 211 { 212 size_t left_over = ctx->buflen; 213 size_t add = 128 - left_over > len ? len : 128 - left_over; 214 215 memcpy (&ctx->buffer[left_over], buffer, add); 216 ctx->buflen += add; 217 218 if (left_over + add > 64) 219 { 220 md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx); 221 /* The regions in the following copy operation cannot overlap. */ 222 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], 223 (left_over + add) & 63); 224 ctx->buflen = (left_over + add) & 63; 225 } 226 227 buffer = (const void *) ((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 /* To check alignment gcc has an appropriate operator. Other 236 compilers don't. */ 237 # if __GNUC__ >= 2 238 # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0) 239 # else 240 # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0) 241 # endif 242 if (UNALIGNED_P (buffer)) 243 while (len > 64) 244 { 245 memcpy (ctx->buffer, buffer, 64); 246 md5_process_block (ctx->buffer, 64, ctx); 247 buffer = (const char *) buffer + 64; 248 len -= 64; 249 } 250 else 251 #endif 252 { 253 md5_process_block (buffer, len & ~63, ctx); 254 buffer = (const void *) ((const char *) buffer + (len & ~63)); 255 len &= 63; 256 } 257 } 258 259 /* Move remaining bytes in internal buffer. */ 260 if (len > 0) 261 { 262 memcpy (ctx->buffer, buffer, len); 263 ctx->buflen = len; 264 } 265 } 266 267 268 /* These are the four functions used in the four steps of the MD5 algorithm 269 and defined in the RFC 1321. The first function is a little bit optimized 270 (as found in Colin Plumbs public domain implementation). */ 271 /* #define FF(b, c, d) ((b & c) | (~b & d)) */ 272 #define FF(b, c, d) (d ^ (b & (c ^ d))) 273 #define FG(b, c, d) FF (d, b, c) 274 #define FH(b, c, d) (b ^ c ^ d) 275 #define FI(b, c, d) (c ^ (b | ~d)) 276 277 /* Process LEN bytes of BUFFER, accumulating context into CTX. 278 It is assumed that LEN % 64 == 0. */ 279 280 void 281 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx) 282 { 283 md5_uint32 correct_words[16]; 284 const md5_uint32 *words = (const md5_uint32 *) buffer; 285 size_t nwords = len / sizeof (md5_uint32); 286 const md5_uint32 *endp = words + nwords; 287 md5_uint32 A = ctx->A; 288 md5_uint32 B = ctx->B; 289 md5_uint32 C = ctx->C; 290 md5_uint32 D = ctx->D; 291 292 /* First increment the byte count. RFC 1321 specifies the possible 293 length of the file up to 2^64 bits. Here we only compute the 294 number of bytes. Do a double word increment. */ 295 ctx->total[0] += len; 296 ctx->total[1] += ((len >> 31) >> 1) + (ctx->total[0] < len); 297 298 /* Process all bytes in the buffer with 64 bytes in each round of 299 the loop. */ 300 while (words < endp) 301 { 302 md5_uint32 *cwp = correct_words; 303 md5_uint32 A_save = A; 304 md5_uint32 B_save = B; 305 md5_uint32 C_save = C; 306 md5_uint32 D_save = D; 307 308 /* First round: using the given function, the context and a constant 309 the next context is computed. Because the algorithms processing 310 unit is a 32-bit word and it is determined to work on words in 311 little endian byte order we perhaps have to change the byte order 312 before the computation. To reduce the work for the next steps 313 we store the swapped words in the array CORRECT_WORDS. */ 314 315 #define OP(a, b, c, d, s, T) \ 316 do \ 317 { \ 318 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ 319 ++words; \ 320 CYCLIC (a, s); \ 321 a += b; \ 322 } \ 323 while (0) 324 325 /* It is unfortunate that C does not provide an operator for 326 cyclic rotation. Hope the C compiler is smart enough. */ 327 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) 328 329 /* Before we start, one word to the strange constants. 330 They are defined in RFC 1321 as 331 332 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 333 */ 334 335 /* Round 1. */ 336 OP (A, B, C, D, 7, (md5_uint32) 0xd76aa478); 337 OP (D, A, B, C, 12, (md5_uint32) 0xe8c7b756); 338 OP (C, D, A, B, 17, (md5_uint32) 0x242070db); 339 OP (B, C, D, A, 22, (md5_uint32) 0xc1bdceee); 340 OP (A, B, C, D, 7, (md5_uint32) 0xf57c0faf); 341 OP (D, A, B, C, 12, (md5_uint32) 0x4787c62a); 342 OP (C, D, A, B, 17, (md5_uint32) 0xa8304613); 343 OP (B, C, D, A, 22, (md5_uint32) 0xfd469501); 344 OP (A, B, C, D, 7, (md5_uint32) 0x698098d8); 345 OP (D, A, B, C, 12, (md5_uint32) 0x8b44f7af); 346 OP (C, D, A, B, 17, (md5_uint32) 0xffff5bb1); 347 OP (B, C, D, A, 22, (md5_uint32) 0x895cd7be); 348 OP (A, B, C, D, 7, (md5_uint32) 0x6b901122); 349 OP (D, A, B, C, 12, (md5_uint32) 0xfd987193); 350 OP (C, D, A, B, 17, (md5_uint32) 0xa679438e); 351 OP (B, C, D, A, 22, (md5_uint32) 0x49b40821); 352 353 /* For the second to fourth round we have the possibly swapped words 354 in CORRECT_WORDS. Redefine the macro to take an additional first 355 argument specifying the function to use. */ 356 #undef OP 357 #define OP(a, b, c, d, k, s, T) \ 358 do \ 359 { \ 360 a += FX (b, c, d) + correct_words[k] + T; \ 361 CYCLIC (a, s); \ 362 a += b; \ 363 } \ 364 while (0) 365 366 #define FX(b, c, d) FG (b, c, d) 367 368 /* Round 2. */ 369 OP (A, B, C, D, 1, 5, (md5_uint32) 0xf61e2562); 370 OP (D, A, B, C, 6, 9, (md5_uint32) 0xc040b340); 371 OP (C, D, A, B, 11, 14, (md5_uint32) 0x265e5a51); 372 OP (B, C, D, A, 0, 20, (md5_uint32) 0xe9b6c7aa); 373 OP (A, B, C, D, 5, 5, (md5_uint32) 0xd62f105d); 374 OP (D, A, B, C, 10, 9, (md5_uint32) 0x02441453); 375 OP (C, D, A, B, 15, 14, (md5_uint32) 0xd8a1e681); 376 OP (B, C, D, A, 4, 20, (md5_uint32) 0xe7d3fbc8); 377 OP (A, B, C, D, 9, 5, (md5_uint32) 0x21e1cde6); 378 OP (D, A, B, C, 14, 9, (md5_uint32) 0xc33707d6); 379 OP (C, D, A, B, 3, 14, (md5_uint32) 0xf4d50d87); 380 OP (B, C, D, A, 8, 20, (md5_uint32) 0x455a14ed); 381 OP (A, B, C, D, 13, 5, (md5_uint32) 0xa9e3e905); 382 OP (D, A, B, C, 2, 9, (md5_uint32) 0xfcefa3f8); 383 OP (C, D, A, B, 7, 14, (md5_uint32) 0x676f02d9); 384 OP (B, C, D, A, 12, 20, (md5_uint32) 0x8d2a4c8a); 385 386 #undef FX 387 #define FX(b, c, d) FH (b, c, d) 388 389 /* Round 3. */ 390 OP (A, B, C, D, 5, 4, (md5_uint32) 0xfffa3942); 391 OP (D, A, B, C, 8, 11, (md5_uint32) 0x8771f681); 392 OP (C, D, A, B, 11, 16, (md5_uint32) 0x6d9d6122); 393 OP (B, C, D, A, 14, 23, (md5_uint32) 0xfde5380c); 394 OP (A, B, C, D, 1, 4, (md5_uint32) 0xa4beea44); 395 OP (D, A, B, C, 4, 11, (md5_uint32) 0x4bdecfa9); 396 OP (C, D, A, B, 7, 16, (md5_uint32) 0xf6bb4b60); 397 OP (B, C, D, A, 10, 23, (md5_uint32) 0xbebfbc70); 398 OP (A, B, C, D, 13, 4, (md5_uint32) 0x289b7ec6); 399 OP (D, A, B, C, 0, 11, (md5_uint32) 0xeaa127fa); 400 OP (C, D, A, B, 3, 16, (md5_uint32) 0xd4ef3085); 401 OP (B, C, D, A, 6, 23, (md5_uint32) 0x04881d05); 402 OP (A, B, C, D, 9, 4, (md5_uint32) 0xd9d4d039); 403 OP (D, A, B, C, 12, 11, (md5_uint32) 0xe6db99e5); 404 OP (C, D, A, B, 15, 16, (md5_uint32) 0x1fa27cf8); 405 OP (B, C, D, A, 2, 23, (md5_uint32) 0xc4ac5665); 406 407 #undef FX 408 #define FX(b, c, d) FI (b, c, d) 409 410 /* Round 4. */ 411 OP (A, B, C, D, 0, 6, (md5_uint32) 0xf4292244); 412 OP (D, A, B, C, 7, 10, (md5_uint32) 0x432aff97); 413 OP (C, D, A, B, 14, 15, (md5_uint32) 0xab9423a7); 414 OP (B, C, D, A, 5, 21, (md5_uint32) 0xfc93a039); 415 OP (A, B, C, D, 12, 6, (md5_uint32) 0x655b59c3); 416 OP (D, A, B, C, 3, 10, (md5_uint32) 0x8f0ccc92); 417 OP (C, D, A, B, 10, 15, (md5_uint32) 0xffeff47d); 418 OP (B, C, D, A, 1, 21, (md5_uint32) 0x85845dd1); 419 OP (A, B, C, D, 8, 6, (md5_uint32) 0x6fa87e4f); 420 OP (D, A, B, C, 15, 10, (md5_uint32) 0xfe2ce6e0); 421 OP (C, D, A, B, 6, 15, (md5_uint32) 0xa3014314); 422 OP (B, C, D, A, 13, 21, (md5_uint32) 0x4e0811a1); 423 OP (A, B, C, D, 4, 6, (md5_uint32) 0xf7537e82); 424 OP (D, A, B, C, 11, 10, (md5_uint32) 0xbd3af235); 425 OP (C, D, A, B, 2, 15, (md5_uint32) 0x2ad7d2bb); 426 OP (B, C, D, A, 9, 21, (md5_uint32) 0xeb86d391); 427 428 /* Add the starting values of the context. */ 429 A += A_save; 430 B += B_save; 431 C += C_save; 432 D += D_save; 433 } 434 435 /* Put checksum in context given as argument. */ 436 ctx->A = A; 437 ctx->B = B; 438 ctx->C = C; 439 ctx->D = D; 440 } 441