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 } 431