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, 1996, 1997, 1999, 2000, 2001, 2002, 2003, 2004, 4 2005, 2006, 2007 Free Software Foundation, Inc. 5 This file is part of the GNU Emacs. 6 7 The GNU C Library is free software; you can redistribute it and/or 8 modify it under the terms of the GNU General Public License as 9 published by the Free Software Foundation; either version 2 of the 10 License, or (at your option) any later version. 11 12 The GNU C Library is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 General Public License for more details. 16 17 You should have received a copy of the GNU General Public 18 License along with the GNU C Library; see the file COPYING. If not, 19 write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 20 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#ifdef _LIBC 40# include <endian.h> 41# if __BYTE_ORDER == __BIG_ENDIAN 42# define WORDS_BIG_ENDIAN 1 43# endif 44/* We need to keep the namespace clean so define the MD5 function 45 protected using leading __ . */ 46# define md5_init_ctx __md5_init_ctx 47# define md5_process_block __md5_process_block 48# define md5_process_bytes __md5_process_bytes 49# define md5_finish_ctx __md5_finish_ctx 50# define md5_read_ctx __md5_read_ctx 51# define md5_stream __md5_stream 52# define md5_buffer __md5_buffer 53#endif 54 55#include "md5.h" 56 57#ifdef WORDS_BIG_ENDIAN 58# define SWAP(n) \ 59 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) 60#else 61# define SWAP(n) (n) 62#endif 63 64 65/* This array contains the bytes used to pad the buffer to the next 66 64-byte boundary. (RFC 1321, 3.1: Step 1) */ 67static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; 68 69 70/* Initialize structure containing state of computation. 71 (RFC 1321, 3.3: Step 3) */ 72void 73md5_init_ctx (ctx) 74 struct md5_ctx *ctx; 75{ 76 ctx->A = 0x67452301; 77 ctx->B = 0xefcdab89; 78 ctx->C = 0x98badcfe; 79 ctx->D = 0x10325476; 80 81 ctx->total[0] = ctx->total[1] = 0; 82 ctx->buflen = 0; 83} 84 85/* Put result from CTX in first 16 bytes following RESBUF. The result 86 must be in little endian byte order. 87 88 IMPORTANT: On some systems it is required that RESBUF is correctly 89 aligned for a 32 bits value. */ 90void * 91md5_read_ctx (ctx, resbuf) 92 const struct md5_ctx *ctx; 93 void *resbuf; 94{ 95 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A); 96 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B); 97 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C); 98 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D); 99 100 return resbuf; 101} 102 103/* Process the remaining bytes in the internal buffer and the usual 104 prolog according to the standard and write the result to RESBUF. 105 106 IMPORTANT: On some systems it is required that RESBUF is correctly 107 aligned for a 32 bits value. */ 108void * 109md5_finish_ctx (ctx, resbuf) 110 struct md5_ctx *ctx; 111 void *resbuf; 112{ 113 /* Take yet unprocessed bytes into account. */ 114 md5_uint32 bytes = ctx->buflen; 115 size_t pad; 116 117 /* Now count remaining bytes. */ 118 ctx->total[0] += bytes; 119 if (ctx->total[0] < bytes) 120 ++ctx->total[1]; 121 122 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; 123 memcpy (&ctx->buffer[bytes], fillbuf, pad); 124 125 /* Put the 64-bit file length in *bits* at the end of the buffer. */ 126 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3); 127 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) | 128 (ctx->total[0] >> 29)); 129 130 /* Process last bytes. */ 131 md5_process_block (ctx->buffer, bytes + pad + 8, ctx); 132 133 return md5_read_ctx (ctx, resbuf); 134} 135 136/* Compute MD5 message digest for bytes read from STREAM. The 137 resulting message digest number will be written into the 16 bytes 138 beginning at RESBLOCK. */ 139int 140md5_stream (stream, resblock) 141 FILE *stream; 142 void *resblock; 143{ 144 /* Important: BLOCKSIZE must be a multiple of 64. */ 145#define BLOCKSIZE 4096 146 struct md5_ctx ctx; 147 char buffer[BLOCKSIZE + 72]; 148 size_t sum; 149 150 /* Initialize the computation context. */ 151 md5_init_ctx (&ctx); 152 153 /* Iterate over full file contents. */ 154 while (1) 155 { 156 /* We read the file in blocks of BLOCKSIZE bytes. One call of the 157 computation function processes the whole buffer so that with the 158 next round of the loop another block can be read. */ 159 size_t n; 160 sum = 0; 161 162 /* Read block. Take care for partial reads. */ 163 do 164 { 165 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); 166 167 sum += n; 168 } 169 while (sum < BLOCKSIZE && n != 0); 170 if (n == 0 && ferror (stream)) 171 return 1; 172 173 /* If end of file is reached, end the loop. */ 174 if (n == 0) 175 break; 176 177 /* Process buffer with BLOCKSIZE bytes. Note that 178 BLOCKSIZE % 64 == 0 179 */ 180 md5_process_block (buffer, BLOCKSIZE, &ctx); 181 } 182 183 /* Add the last bytes if necessary. */ 184 if (sum > 0) 185 md5_process_bytes (buffer, sum, &ctx); 186 187 /* Construct result in desired memory. */ 188 md5_finish_ctx (&ctx, resblock); 189 return 0; 190} 191 192/* Compute MD5 message digest for LEN bytes beginning at BUFFER. The 193 result is always in little endian byte order, so that a byte-wise 194 output yields to the wanted ASCII representation of the message 195 digest. */ 196void * 197md5_buffer (buffer, len, resblock) 198 const char *buffer; 199 size_t len; 200 void *resblock; 201{ 202 struct md5_ctx ctx; 203 204 /* Initialize the computation context. */ 205 md5_init_ctx (&ctx); 206 207 /* Process whole buffer but last len % 64 bytes. */ 208 md5_process_bytes (buffer, len, &ctx); 209 210 /* Put result in desired memory area. */ 211 return md5_finish_ctx (&ctx, resblock); 212} 213 214 215void 216md5_process_bytes (buffer, len, ctx) 217 const void *buffer; 218 size_t len; 219 struct md5_ctx *ctx; 220{ 221 /* const void aligned_buffer = buffer; */ 222 223 /* When we already have some bits in our internal buffer concatenate 224 both inputs first. */ 225 if (ctx->buflen != 0) 226 { 227 size_t left_over = ctx->buflen; 228 size_t add = 128 - left_over > len ? len : 128 - left_over; 229 230 /* Only put full words in the buffer. */ 231 add -= add % __alignof__ (md5_uint32); 232 233 memcpy (&ctx->buffer[left_over], buffer, add); 234 ctx->buflen += add; 235 236 if (ctx->buflen > 64) 237 { 238 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx); 239 240 ctx->buflen &= 63; 241 /* The regions in the following copy operation cannot overlap. */ 242 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], 243 ctx->buflen); 244 } 245 246 buffer = (const char *) buffer + add; 247 len -= add; 248 } 249 250 /* Process available complete blocks. */ 251 if (len > 64) 252 { 253 md5_process_block (buffer, len & ~63, ctx); 254 buffer = (const char *) buffer + (len & ~63); 255 len &= 63; 256 } 257 258 /* Move remaining bytes in internal buffer. */ 259 if (len > 0) 260 { 261 size_t left_over = ctx->buflen; 262 263 memcpy (&ctx->buffer[left_over], buffer, len); 264 left_over += len; 265 if (left_over >= 64) 266 { 267 md5_process_block (ctx->buffer, 64, ctx); 268 left_over -= 64; 269 memcpy (ctx->buffer, &ctx->buffer[64], left_over); 270 } 271 ctx->buflen = left_over; 272 } 273} 274 275 276/* These are the four functions used in the four steps of the MD5 algorithm 277 and defined in the RFC 1321. The first function is a little bit optimized 278 (as found in Colin Plumbs public domain implementation). */ 279/* #define FF(b, c, d) ((b & c) | (~b & d)) */ 280#define FF(b, c, d) (d ^ (b & (c ^ d))) 281#define FG(b, c, d) FF (d, b, c) 282#define FH(b, c, d) (b ^ c ^ d) 283#define FI(b, c, d) (c ^ (b | ~d)) 284 285/* Process LEN bytes of BUFFER, accumulating context into CTX. 286 It is assumed that LEN % 64 == 0. */ 287 288void 289md5_process_block (buffer, len, ctx) 290 const void *buffer; 291 size_t len; 292 struct md5_ctx *ctx; 293{ 294 md5_uint32 correct_words[16]; 295 const md5_uint32 *words = buffer; 296 size_t nwords = len / sizeof (md5_uint32); 297 const md5_uint32 *endp = words + nwords; 298 md5_uint32 A = ctx->A; 299 md5_uint32 B = ctx->B; 300 md5_uint32 C = ctx->C; 301 md5_uint32 D = ctx->D; 302 303 /* First increment the byte count. RFC 1321 specifies the possible 304 length of the file up to 2^64 bits. Here we only compute the 305 number of bytes. Do a double word increment. */ 306 ctx->total[0] += len; 307 if (ctx->total[0] < len) 308 ++ctx->total[1]; 309 310 /* Process all bytes in the buffer with 64 bytes in each round of 311 the loop. */ 312 while (words < endp) 313 { 314 md5_uint32 *cwp = correct_words; 315 md5_uint32 A_save = A; 316 md5_uint32 B_save = B; 317 md5_uint32 C_save = C; 318 md5_uint32 D_save = D; 319 320 /* First round: using the given function, the context and a constant 321 the next context is computed. Because the algorithms processing 322 unit is a 32-bit word and it is determined to work on words in 323 little endian byte order we perhaps have to change the byte order 324 before the computation. To reduce the work for the next steps 325 we store the swapped words in the array CORRECT_WORDS. */ 326 327#define OP(a, b, c, d, s, T) \ 328 do \ 329 { \ 330 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ 331 ++words; \ 332 CYCLIC (a, s); \ 333 a += b; \ 334 } \ 335 while (0) 336 337 /* It is unfortunate that C does not provide an operator for 338 cyclic rotation. Hope the C compiler is smart enough. */ 339#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) 340 341 /* Before we start, one word to the strange constants. 342 They are defined in RFC 1321 as 343 344 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 345 */ 346 347 /* Round 1. */ 348 OP (A, B, C, D, 7, 0xd76aa478); 349 OP (D, A, B, C, 12, 0xe8c7b756); 350 OP (C, D, A, B, 17, 0x242070db); 351 OP (B, C, D, A, 22, 0xc1bdceee); 352 OP (A, B, C, D, 7, 0xf57c0faf); 353 OP (D, A, B, C, 12, 0x4787c62a); 354 OP (C, D, A, B, 17, 0xa8304613); 355 OP (B, C, D, A, 22, 0xfd469501); 356 OP (A, B, C, D, 7, 0x698098d8); 357 OP (D, A, B, C, 12, 0x8b44f7af); 358 OP (C, D, A, B, 17, 0xffff5bb1); 359 OP (B, C, D, A, 22, 0x895cd7be); 360 OP (A, B, C, D, 7, 0x6b901122); 361 OP (D, A, B, C, 12, 0xfd987193); 362 OP (C, D, A, B, 17, 0xa679438e); 363 OP (B, C, D, A, 22, 0x49b40821); 364 365 /* For the second to fourth round we have the possibly swapped words 366 in CORRECT_WORDS. Redefine the macro to take an additional first 367 argument specifying the function to use. */ 368#undef OP 369#define OP(f, a, b, c, d, k, s, T) \ 370 do \ 371 { \ 372 a += f (b, c, d) + correct_words[k] + T; \ 373 CYCLIC (a, s); \ 374 a += b; \ 375 } \ 376 while (0) 377 378 /* Round 2. */ 379 OP (FG, A, B, C, D, 1, 5, 0xf61e2562); 380 OP (FG, D, A, B, C, 6, 9, 0xc040b340); 381 OP (FG, C, D, A, B, 11, 14, 0x265e5a51); 382 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa); 383 OP (FG, A, B, C, D, 5, 5, 0xd62f105d); 384 OP (FG, D, A, B, C, 10, 9, 0x02441453); 385 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681); 386 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8); 387 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6); 388 OP (FG, D, A, B, C, 14, 9, 0xc33707d6); 389 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87); 390 OP (FG, B, C, D, A, 8, 20, 0x455a14ed); 391 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905); 392 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8); 393 OP (FG, C, D, A, B, 7, 14, 0x676f02d9); 394 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a); 395 396 /* Round 3. */ 397 OP (FH, A, B, C, D, 5, 4, 0xfffa3942); 398 OP (FH, D, A, B, C, 8, 11, 0x8771f681); 399 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122); 400 OP (FH, B, C, D, A, 14, 23, 0xfde5380c); 401 OP (FH, A, B, C, D, 1, 4, 0xa4beea44); 402 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9); 403 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60); 404 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70); 405 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6); 406 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa); 407 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085); 408 OP (FH, B, C, D, A, 6, 23, 0x04881d05); 409 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039); 410 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5); 411 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8); 412 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665); 413 414 /* Round 4. */ 415 OP (FI, A, B, C, D, 0, 6, 0xf4292244); 416 OP (FI, D, A, B, C, 7, 10, 0x432aff97); 417 OP (FI, C, D, A, B, 14, 15, 0xab9423a7); 418 OP (FI, B, C, D, A, 5, 21, 0xfc93a039); 419 OP (FI, A, B, C, D, 12, 6, 0x655b59c3); 420 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92); 421 OP (FI, C, D, A, B, 10, 15, 0xffeff47d); 422 OP (FI, B, C, D, A, 1, 21, 0x85845dd1); 423 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f); 424 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0); 425 OP (FI, C, D, A, B, 6, 15, 0xa3014314); 426 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1); 427 OP (FI, A, B, C, D, 4, 6, 0xf7537e82); 428 OP (FI, D, A, B, C, 11, 10, 0xbd3af235); 429 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb); 430 OP (FI, B, C, D, A, 9, 21, 0xeb86d391); 431 432 /* Add the starting values of the context. */ 433 A += A_save; 434 B += B_save; 435 C += C_save; 436 D += D_save; 437 } 438 439 /* Put checksum in context given as argument. */ 440 ctx->A = A; 441 ctx->B = B; 442 ctx->C = C; 443 ctx->D = D; 444} 445 446/* arch-tag: 60084f04-b434-42cb-9d2b-e91df01f4325 447 (do not change this comment) */ 448