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, 1997 Free Software Foundation, Inc. 4 This file is part of the GNU C Library. 5 6 The GNU C Library is free software; you can redistribute it and/or 7 modify it under the terms of the GNU Library General Public License as 8 published by the Free Software Foundation; either version 2 of the 9 License, or (at your option) any later version. 10 11 The GNU C Library is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 Library General Public License for more details. 15 16 You should have received a copy of the GNU Library General Public 17 License along with the GNU C Library; see the file COPYING.LIB. If not, 18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, 19 Boston, MA 02111-1307, USA. */ 20 21/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */ 22 23#ifdef HAVE_CONFIG_H 24# include <config.h> 25#endif 26 27#include <sys/types.h> 28 29#if STDC_HEADERS || defined _LIBC 30# include <stdlib.h> 31# include <string.h> 32#else 33# ifndef HAVE_MEMCPY 34# define memcpy(d, s, n) bcopy ((s), (d), (n)) 35# endif 36#endif 37 38#include "md5-gnu.h" 39 40#ifdef _LIBC 41# include <endian.h> 42# if __BYTE_ORDER == __BIG_ENDIAN 43# define WORDS_BIGENDIAN 1 44# endif 45/* We need to keep the namespace clean so define the MD5 function 46 protected using leading __ and use weak aliases. */ 47# define md5_init_ctx __md5_init_ctx 48# define md5_process_block __md5_process_block 49# define md5_process_bytes __md5_process_bytes 50# define md5_finish_ctx __md5_finish_ctx 51# define md5_read_ctx __md5_read_ctx 52# define md5_stream __md5_stream 53# define md5_buffer __md5_buffer 54#endif 55 56#ifdef WORDS_BIGENDIAN 57# define SWAP(n) \ 58 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) 59#else 60# define SWAP(n) (n) 61#endif 62 63 64/* This array contains the bytes used to pad the buffer to the next 65 64-byte boundary. (RFC 1321, 3.1: Step 1) */ 66static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; 67 68 69/* Initialize structure containing state of computation. 70 (RFC 1321, 3.3: Step 3) */ 71void 72md5_init_ctx (ctx) 73 struct md5_ctx *ctx; 74{ 75 ctx->A = 0x67452301; 76 ctx->B = 0xefcdab89; 77 ctx->C = 0x98badcfe; 78 ctx->D = 0x10325476; 79 80 ctx->total[0] = ctx->total[1] = 0; 81 ctx->buflen = 0; 82} 83 84/* Put result from CTX in first 16 bytes following RESBUF. The result 85 must be in little endian byte order. 86 87 IMPORTANT: On some systems it is required that RESBUF is correctly 88 aligned for a 32 bits value. */ 89void * 90md5_read_ctx (ctx, resbuf) 91 const struct md5_ctx *ctx; 92 void *resbuf; 93{ 94 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A); 95 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B); 96 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C); 97 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D); 98 99 return resbuf; 100} 101 102/* Process the remaining bytes in the internal buffer and the usual 103 prolog according to the standard and write the result to RESBUF. 104 105 IMPORTANT: On some systems it is required that RESBUF is correctly 106 aligned for a 32 bits value. */ 107void * 108md5_finish_ctx (ctx, resbuf) 109 struct md5_ctx *ctx; 110 void *resbuf; 111{ 112 /* Take yet unprocessed bytes into account. */ 113 md5_uint32 bytes = ctx->buflen; 114 size_t pad; 115 116 /* Now count remaining bytes. */ 117 ctx->total[0] += bytes; 118 if (ctx->total[0] < bytes) 119 ++ctx->total[1]; 120 121 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; 122 memcpy (&ctx->buffer[bytes], fillbuf, pad); 123 124 /* Put the 64-bit file length in *bits* at the end of the buffer. */ 125 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3); 126 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) | 127 (ctx->total[0] >> 29)); 128 129 /* Process last bytes. */ 130 md5_process_block (ctx->buffer, bytes + pad + 8, ctx); 131 132 return md5_read_ctx (ctx, resbuf); 133} 134 135/* Compute MD5 message digest for bytes read from STREAM. The 136 resulting message digest number will be written into the 16 bytes 137 beginning at RESBLOCK. */ 138int 139md5_stream (stream, resblock) 140 FILE *stream; 141 void *resblock; 142{ 143 /* Important: BLOCKSIZE must be a multiple of 64. */ 144#define BLOCKSIZE 4096 145 struct md5_ctx ctx; 146 char buffer[BLOCKSIZE + 72]; 147 size_t sum; 148 149 /* Initialize the computation context. */ 150 md5_init_ctx (&ctx); 151 152 /* Iterate over full file contents. */ 153 while (1) 154 { 155 /* We read the file in blocks of BLOCKSIZE bytes. One call of the 156 computation function processes the whole buffer so that with the 157 next round of the loop another block can be read. */ 158 size_t n; 159 sum = 0; 160 161 /* Read block. Take care for partial reads. */ 162 do 163 { 164 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); 165 166 sum += n; 167 } 168 while (sum < BLOCKSIZE && n != 0); 169 if (n == 0 && ferror (stream)) 170 return 1; 171 172 /* If end of file is reached, end the loop. */ 173 if (n == 0) 174 break; 175 176 /* Process buffer with BLOCKSIZE bytes. Note that 177 BLOCKSIZE % 64 == 0 178 */ 179 md5_process_block (buffer, BLOCKSIZE, &ctx); 180 } 181 182 /* Add the last bytes if necessary. */ 183 if (sum > 0) 184 md5_process_bytes (buffer, sum, &ctx); 185 186 /* Construct result in desired memory. */ 187 md5_finish_ctx (&ctx, resblock); 188 return 0; 189} 190 191/* Compute MD5 message digest for LEN bytes beginning at BUFFER. The 192 result is always in little endian byte order, so that a byte-wise 193 output yields to the wanted ASCII representation of the message 194 digest. */ 195void * 196md5_buffer (buffer, len, resblock) 197 const char *buffer; 198 size_t len; 199 void *resblock; 200{ 201 struct md5_ctx ctx; 202 203 /* Initialize the computation context. */ 204 md5_init_ctx (&ctx); 205 206 /* Process whole buffer but last len % 64 bytes. */ 207 md5_process_bytes (buffer, len, &ctx); 208 209 /* Put result in desired memory area. */ 210 return md5_finish_ctx (&ctx, resblock); 211} 212 213 214void 215md5_process_bytes (buffer, len, ctx) 216 const void *buffer; 217 size_t len; 218 struct md5_ctx *ctx; 219{ 220 /* When we already have some bits in our internal buffer concatenate 221 both inputs first. */ 222 if (ctx->buflen != 0) 223 { 224 size_t left_over = ctx->buflen; 225 size_t add = 128 - left_over > len ? len : 128 - left_over; 226 227 memcpy (&ctx->buffer[left_over], buffer, add); 228 ctx->buflen += add; 229 230 if (left_over + add > 64) 231 { 232 md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx); 233 /* The regions in the following copy operation cannot overlap. */ 234 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], 235 (left_over + add) & 63); 236 ctx->buflen = (left_over + add) & 63; 237 } 238 239 buffer = (const char *) buffer + add; 240 len -= add; 241 } 242 243 /* Process available complete blocks. */ 244 if (len > 64) 245 { 246 md5_process_block (buffer, len & ~63, ctx); 247 buffer = (const char *) buffer + (len & ~63); 248 len &= 63; 249 } 250 251 /* Move remaining bytes in internal buffer. */ 252 if (len > 0) 253 { 254 memcpy (ctx->buffer, buffer, len); 255 ctx->buflen = len; 256 } 257} 258 259 260/* These are the four functions used in the four steps of the MD5 algorithm 261 and defined in the RFC 1321. The first function is a little bit optimized 262 (as found in Colin Plumbs public domain implementation). */ 263/* #define FF(b, c, d) ((b & c) | (~b & d)) */ 264#define FF(b, c, d) (d ^ (b & (c ^ d))) 265#define FG(b, c, d) FF (d, b, c) 266#define FH(b, c, d) (b ^ c ^ d) 267#define FI(b, c, d) (c ^ (b | ~d)) 268 269/* Process LEN bytes of BUFFER, accumulating context into CTX. 270 It is assumed that LEN % 64 == 0. */ 271 272void 273md5_process_block (buffer, len, ctx) 274 const void *buffer; 275 size_t len; 276 struct md5_ctx *ctx; 277{ 278 md5_uint32 correct_words[16]; 279 const md5_uint32 *words = buffer; 280 size_t nwords = len / sizeof (md5_uint32); 281 const md5_uint32 *endp = words + nwords; 282 md5_uint32 A = ctx->A; 283 md5_uint32 B = ctx->B; 284 md5_uint32 C = ctx->C; 285 md5_uint32 D = ctx->D; 286 287 /* First increment the byte count. RFC 1321 specifies the possible 288 length of the file up to 2^64 bits. Here we only compute the 289 number of bytes. Do a double word increment. */ 290 ctx->total[0] += len; 291 if (ctx->total[0] < len) 292 ++ctx->total[1]; 293 294 /* Process all bytes in the buffer with 64 bytes in each round of 295 the loop. */ 296 while (words < endp) 297 { 298 md5_uint32 *cwp = correct_words; 299 md5_uint32 A_save = A; 300 md5_uint32 B_save = B; 301 md5_uint32 C_save = C; 302 md5_uint32 D_save = D; 303 304 /* First round: using the given function, the context and a constant 305 the next context is computed. Because the algorithms processing 306 unit is a 32-bit word and it is determined to work on words in 307 little endian byte order we perhaps have to change the byte order 308 before the computation. To reduce the work for the next steps 309 we store the swapped words in the array CORRECT_WORDS. */ 310 311#define OP(a, b, c, d, s, T) \ 312 do \ 313 { \ 314 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ 315 ++words; \ 316 CYCLIC (a, s); \ 317 a += b; \ 318 } \ 319 while (0) 320 321 /* It is unfortunate that C does not provide an operator for 322 cyclic rotation. Hope the C compiler is smart enough. */ 323#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) 324 325 /* Before we start, one word to the strange constants. 326 They are defined in RFC 1321 as 327 328 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 329 */ 330 331 /* Round 1. */ 332 OP (A, B, C, D, 7, 0xd76aa478); 333 OP (D, A, B, C, 12, 0xe8c7b756); 334 OP (C, D, A, B, 17, 0x242070db); 335 OP (B, C, D, A, 22, 0xc1bdceee); 336 OP (A, B, C, D, 7, 0xf57c0faf); 337 OP (D, A, B, C, 12, 0x4787c62a); 338 OP (C, D, A, B, 17, 0xa8304613); 339 OP (B, C, D, A, 22, 0xfd469501); 340 OP (A, B, C, D, 7, 0x698098d8); 341 OP (D, A, B, C, 12, 0x8b44f7af); 342 OP (C, D, A, B, 17, 0xffff5bb1); 343 OP (B, C, D, A, 22, 0x895cd7be); 344 OP (A, B, C, D, 7, 0x6b901122); 345 OP (D, A, B, C, 12, 0xfd987193); 346 OP (C, D, A, B, 17, 0xa679438e); 347 OP (B, C, D, A, 22, 0x49b40821); 348 349 /* For the second to fourth round we have the possibly swapped words 350 in CORRECT_WORDS. Redefine the macro to take an additional first 351 argument specifying the function to use. */ 352#undef OP 353#define OP(f, a, b, c, d, k, s, T) \ 354 do \ 355 { \ 356 a += f (b, c, d) + correct_words[k] + T; \ 357 CYCLIC (a, s); \ 358 a += b; \ 359 } \ 360 while (0) 361 362 /* Round 2. */ 363 OP (FG, A, B, C, D, 1, 5, 0xf61e2562); 364 OP (FG, D, A, B, C, 6, 9, 0xc040b340); 365 OP (FG, C, D, A, B, 11, 14, 0x265e5a51); 366 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa); 367 OP (FG, A, B, C, D, 5, 5, 0xd62f105d); 368 OP (FG, D, A, B, C, 10, 9, 0x02441453); 369 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681); 370 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8); 371 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6); 372 OP (FG, D, A, B, C, 14, 9, 0xc33707d6); 373 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87); 374 OP (FG, B, C, D, A, 8, 20, 0x455a14ed); 375 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905); 376 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8); 377 OP (FG, C, D, A, B, 7, 14, 0x676f02d9); 378 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a); 379 380 /* Round 3. */ 381 OP (FH, A, B, C, D, 5, 4, 0xfffa3942); 382 OP (FH, D, A, B, C, 8, 11, 0x8771f681); 383 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122); 384 OP (FH, B, C, D, A, 14, 23, 0xfde5380c); 385 OP (FH, A, B, C, D, 1, 4, 0xa4beea44); 386 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9); 387 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60); 388 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70); 389 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6); 390 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa); 391 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085); 392 OP (FH, B, C, D, A, 6, 23, 0x04881d05); 393 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039); 394 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5); 395 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8); 396 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665); 397 398 /* Round 4. */ 399 OP (FI, A, B, C, D, 0, 6, 0xf4292244); 400 OP (FI, D, A, B, C, 7, 10, 0x432aff97); 401 OP (FI, C, D, A, B, 14, 15, 0xab9423a7); 402 OP (FI, B, C, D, A, 5, 21, 0xfc93a039); 403 OP (FI, A, B, C, D, 12, 6, 0x655b59c3); 404 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92); 405 OP (FI, C, D, A, B, 10, 15, 0xffeff47d); 406 OP (FI, B, C, D, A, 1, 21, 0x85845dd1); 407 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f); 408 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0); 409 OP (FI, C, D, A, B, 6, 15, 0xa3014314); 410 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1); 411 OP (FI, A, B, C, D, 4, 6, 0xf7537e82); 412 OP (FI, D, A, B, C, 11, 10, 0xbd3af235); 413 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb); 414 OP (FI, B, C, D, A, 9, 21, 0xeb86d391); 415 416 /* Add the starting values of the context. */ 417 A += A_save; 418 B += B_save; 419 C += C_save; 420 D += D_save; 421 } 422 423 /* Put checksum in context given as argument. */ 424 ctx->A = A; 425 ctx->B = B; 426 ctx->C = C; 427 ctx->D = D; 428} 429 430 431#ifdef _LIBC 432/* Define weak aliases. */ 433# undef md5_init_ctx 434weak_alias (__md5_init_ctx, md5_init_ctx) 435# undef md5_process_block 436weak_alias (__md5_process_block, md5_process_block) 437# undef md5_process_bytes 438weak_alias (__md5_process_bytes, md5_process_bytes) 439# undef md5_finish_ctx 440weak_alias (__md5_finish_ctx, md5_finish_ctx) 441# undef md5_read_ctx 442weak_alias (__md5_read_ctx, md5_read_ctx) 443# undef md5_stream 444weak_alias (__md5_stream, md5_stream) 445# undef md5_buffer 446weak_alias (__md5_buffer, md5_buffer) 447#endif 448