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) 1995,1996,1997,1999,2000,2001,2005,2006,2008 4 Free Software Foundation, Inc. 5 This file is part of the GNU C Library. 6 7 This program is free software; you can redistribute it and/or modify it 8 under the terms of the GNU General Public License as published by the 9 Free Software Foundation; either version 3, or (at your option) any 10 later version. 11 12 This program 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 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software Foundation, 19 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 20 21/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */ 22 23#include <config.h> 24 25#include "md5.h" 26 27#include <stddef.h> 28#include <stdlib.h> 29#include <string.h> 30#include <sys/types.h> 31 32#if USE_UNLOCKED_IO 33# include "unlocked-io.h" 34#endif 35 36#ifdef _LIBC 37# include <endian.h> 38# if __BYTE_ORDER == __BIG_ENDIAN 39# define WORDS_BIGENDIAN 1 40# endif 41/* We need to keep the namespace clean so define the MD5 function 42 protected using leading __ . */ 43# define md5_init_ctx __md5_init_ctx 44# define md5_process_block __md5_process_block 45# define md5_process_bytes __md5_process_bytes 46# define md5_finish_ctx __md5_finish_ctx 47# define md5_read_ctx __md5_read_ctx 48# define md5_stream __md5_stream 49# define md5_buffer __md5_buffer 50#endif 51 52#ifdef WORDS_BIGENDIAN 53# define SWAP(n) \ 54 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) 55#else 56# define SWAP(n) (n) 57#endif 58 59#define BLOCKSIZE 4096 60#if BLOCKSIZE % 64 != 0 61# error "invalid BLOCKSIZE" 62#endif 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 (struct md5_ctx *ctx) 73{ 74 ctx->A = 0x67452301; 75 ctx->B = 0xefcdab89; 76 ctx->C = 0x98badcfe; 77 ctx->D = 0x10325476; 78 79 ctx->total[0] = ctx->total[1] = 0; 80 ctx->buflen = 0; 81} 82 83/* Copy the 4 byte value from v into the memory location pointed to by *cp, 84 If your architecture allows unaligned access this is equivalent to 85 * (uint32_t *) cp = v */ 86static inline void 87set_uint32 (char *cp, uint32_t v) 88{ 89 memcpy (cp, &v, sizeof v); 90} 91 92/* Put result from CTX in first 16 bytes following RESBUF. The result 93 must be in little endian byte order. */ 94void * 95md5_read_ctx (const struct md5_ctx *ctx, void *resbuf) 96{ 97 char *r = resbuf; 98 set_uint32 (r + 0 * sizeof ctx->A, SWAP (ctx->A)); 99 set_uint32 (r + 1 * sizeof ctx->B, SWAP (ctx->B)); 100 set_uint32 (r + 2 * sizeof ctx->C, SWAP (ctx->C)); 101 set_uint32 (r + 3 * sizeof ctx->D, SWAP (ctx->D)); 102 103 return resbuf; 104} 105 106/* Process the remaining bytes in the internal buffer and the usual 107 prolog according to the standard and write the result to RESBUF. */ 108void * 109md5_finish_ctx (struct md5_ctx *ctx, void *resbuf) 110{ 111 /* Take yet unprocessed bytes into account. */ 112 uint32_t bytes = ctx->buflen; 113 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4; 114 115 /* Now count remaining bytes. */ 116 ctx->total[0] += bytes; 117 if (ctx->total[0] < bytes) 118 ++ctx->total[1]; 119 120 /* Put the 64-bit file length in *bits* at the end of the buffer. */ 121 ctx->buffer[size - 2] = SWAP (ctx->total[0] << 3); 122 ctx->buffer[size - 1] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29)); 123 124 memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes); 125 126 /* Process last bytes. */ 127 md5_process_block (ctx->buffer, size * 4, ctx); 128 129 return md5_read_ctx (ctx, resbuf); 130} 131 132/* Compute MD5 message digest for bytes read from STREAM. The 133 resulting message digest number will be written into the 16 bytes 134 beginning at RESBLOCK. */ 135int 136md5_stream (FILE *stream, void *resblock) 137{ 138 struct md5_ctx ctx; 139 char buffer[BLOCKSIZE + 72]; 140 size_t sum; 141 142 /* Initialize the computation context. */ 143 md5_init_ctx (&ctx); 144 145 /* Iterate over full file contents. */ 146 while (1) 147 { 148 /* We read the file in blocks of BLOCKSIZE bytes. One call of the 149 computation function processes the whole buffer so that with the 150 next round of the loop another block can be read. */ 151 size_t n; 152 sum = 0; 153 154 /* Read block. Take care for partial reads. */ 155 while (1) 156 { 157 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); 158 159 sum += n; 160 161 if (sum == BLOCKSIZE) 162 break; 163 164 if (n == 0) 165 { 166 /* Check for the error flag IFF N == 0, so that we don't 167 exit the loop after a partial read due to e.g., EAGAIN 168 or EWOULDBLOCK. */ 169 if (ferror (stream)) 170 return 1; 171 goto process_partial_block; 172 } 173 174 /* We've read at least one byte, so ignore errors. But always 175 check for EOF, since feof may be true even though N > 0. 176 Otherwise, we could end up calling fread after EOF. */ 177 if (feof (stream)) 178 goto process_partial_block; 179 } 180 181 /* Process buffer with BLOCKSIZE bytes. Note that 182 BLOCKSIZE % 64 == 0 183 */ 184 md5_process_block (buffer, BLOCKSIZE, &ctx); 185 } 186 187process_partial_block: 188 189 /* Process any remaining bytes. */ 190 if (sum > 0) 191 md5_process_bytes (buffer, sum, &ctx); 192 193 /* Construct result in desired memory. */ 194 md5_finish_ctx (&ctx, resblock); 195 return 0; 196} 197 198/* Compute MD5 message digest for LEN bytes beginning at BUFFER. The 199 result is always in little endian byte order, so that a byte-wise 200 output yields to the wanted ASCII representation of the message 201 digest. */ 202void * 203md5_buffer (const char *buffer, size_t len, void *resblock) 204{ 205 struct md5_ctx ctx; 206 207 /* Initialize the computation context. */ 208 md5_init_ctx (&ctx); 209 210 /* Process whole buffer but last len % 64 bytes. */ 211 md5_process_bytes (buffer, len, &ctx); 212 213 /* Put result in desired memory area. */ 214 return md5_finish_ctx (&ctx, resblock); 215} 216 217 218void 219md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx) 220{ 221 /* When we already have some bits in our internal buffer concatenate 222 both inputs first. */ 223 if (ctx->buflen != 0) 224 { 225 size_t left_over = ctx->buflen; 226 size_t add = 128 - left_over > len ? len : 128 - left_over; 227 228 memcpy (&((char *) ctx->buffer)[left_over], buffer, add); 229 ctx->buflen += add; 230 231 if (ctx->buflen > 64) 232 { 233 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx); 234 235 ctx->buflen &= 63; 236 /* The regions in the following copy operation cannot overlap. */ 237 memcpy (ctx->buffer, 238 &((char *) ctx->buffer)[(left_over + add) & ~63], 239 ctx->buflen); 240 } 241 242 buffer = (const char *) buffer + add; 243 len -= add; 244 } 245 246 /* Process available complete blocks. */ 247 if (len >= 64) 248 { 249#if !_STRING_ARCH_unaligned 250# define alignof(type) offsetof (struct { char c; type x; }, x) 251# define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0) 252 if (UNALIGNED_P (buffer)) 253 while (len > 64) 254 { 255 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx); 256 buffer = (const char *) buffer + 64; 257 len -= 64; 258 } 259 else 260#endif 261 { 262 md5_process_block (buffer, len & ~63, ctx); 263 buffer = (const char *) buffer + (len & ~63); 264 len &= 63; 265 } 266 } 267 268 /* Move remaining bytes in internal buffer. */ 269 if (len > 0) 270 { 271 size_t left_over = ctx->buflen; 272 273 memcpy (&((char *) ctx->buffer)[left_over], buffer, len); 274 left_over += len; 275 if (left_over >= 64) 276 { 277 md5_process_block (ctx->buffer, 64, ctx); 278 left_over -= 64; 279 memcpy (ctx->buffer, &ctx->buffer[16], left_over); 280 } 281 ctx->buflen = left_over; 282 } 283} 284 285 286/* These are the four functions used in the four steps of the MD5 algorithm 287 and defined in the RFC 1321. The first function is a little bit optimized 288 (as found in Colin Plumbs public domain implementation). */ 289/* #define FF(b, c, d) ((b & c) | (~b & d)) */ 290#define FF(b, c, d) (d ^ (b & (c ^ d))) 291#define FG(b, c, d) FF (d, b, c) 292#define FH(b, c, d) (b ^ c ^ d) 293#define FI(b, c, d) (c ^ (b | ~d)) 294 295/* Process LEN bytes of BUFFER, accumulating context into CTX. 296 It is assumed that LEN % 64 == 0. */ 297 298void 299md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx) 300{ 301 uint32_t correct_words[16]; 302 const uint32_t *words = buffer; 303 size_t nwords = len / sizeof (uint32_t); 304 const uint32_t *endp = words + nwords; 305 uint32_t A = ctx->A; 306 uint32_t B = ctx->B; 307 uint32_t C = ctx->C; 308 uint32_t D = ctx->D; 309 310 /* First increment the byte count. RFC 1321 specifies the possible 311 length of the file up to 2^64 bits. Here we only compute the 312 number of bytes. Do a double word increment. */ 313 ctx->total[0] += len; 314 if (ctx->total[0] < len) 315 ++ctx->total[1]; 316 317 /* Process all bytes in the buffer with 64 bytes in each round of 318 the loop. */ 319 while (words < endp) 320 { 321 uint32_t *cwp = correct_words; 322 uint32_t A_save = A; 323 uint32_t B_save = B; 324 uint32_t C_save = C; 325 uint32_t D_save = D; 326 327 /* First round: using the given function, the context and a constant 328 the next context is computed. Because the algorithms processing 329 unit is a 32-bit word and it is determined to work on words in 330 little endian byte order we perhaps have to change the byte order 331 before the computation. To reduce the work for the next steps 332 we store the swapped words in the array CORRECT_WORDS. */ 333 334#define OP(a, b, c, d, s, T) \ 335 do \ 336 { \ 337 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ 338 ++words; \ 339 CYCLIC (a, s); \ 340 a += b; \ 341 } \ 342 while (0) 343 344 /* It is unfortunate that C does not provide an operator for 345 cyclic rotation. Hope the C compiler is smart enough. */ 346#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) 347 348 /* Before we start, one word to the strange constants. 349 They are defined in RFC 1321 as 350 351 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 352 353 Here is an equivalent invocation using Perl: 354 355 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}' 356 */ 357 358 /* Round 1. */ 359 OP (A, B, C, D, 7, 0xd76aa478); 360 OP (D, A, B, C, 12, 0xe8c7b756); 361 OP (C, D, A, B, 17, 0x242070db); 362 OP (B, C, D, A, 22, 0xc1bdceee); 363 OP (A, B, C, D, 7, 0xf57c0faf); 364 OP (D, A, B, C, 12, 0x4787c62a); 365 OP (C, D, A, B, 17, 0xa8304613); 366 OP (B, C, D, A, 22, 0xfd469501); 367 OP (A, B, C, D, 7, 0x698098d8); 368 OP (D, A, B, C, 12, 0x8b44f7af); 369 OP (C, D, A, B, 17, 0xffff5bb1); 370 OP (B, C, D, A, 22, 0x895cd7be); 371 OP (A, B, C, D, 7, 0x6b901122); 372 OP (D, A, B, C, 12, 0xfd987193); 373 OP (C, D, A, B, 17, 0xa679438e); 374 OP (B, C, D, A, 22, 0x49b40821); 375 376 /* For the second to fourth round we have the possibly swapped words 377 in CORRECT_WORDS. Redefine the macro to take an additional first 378 argument specifying the function to use. */ 379#undef OP 380#define OP(f, a, b, c, d, k, s, T) \ 381 do \ 382 { \ 383 a += f (b, c, d) + correct_words[k] + T; \ 384 CYCLIC (a, s); \ 385 a += b; \ 386 } \ 387 while (0) 388 389 /* Round 2. */ 390 OP (FG, A, B, C, D, 1, 5, 0xf61e2562); 391 OP (FG, D, A, B, C, 6, 9, 0xc040b340); 392 OP (FG, C, D, A, B, 11, 14, 0x265e5a51); 393 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa); 394 OP (FG, A, B, C, D, 5, 5, 0xd62f105d); 395 OP (FG, D, A, B, C, 10, 9, 0x02441453); 396 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681); 397 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8); 398 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6); 399 OP (FG, D, A, B, C, 14, 9, 0xc33707d6); 400 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87); 401 OP (FG, B, C, D, A, 8, 20, 0x455a14ed); 402 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905); 403 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8); 404 OP (FG, C, D, A, B, 7, 14, 0x676f02d9); 405 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a); 406 407 /* Round 3. */ 408 OP (FH, A, B, C, D, 5, 4, 0xfffa3942); 409 OP (FH, D, A, B, C, 8, 11, 0x8771f681); 410 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122); 411 OP (FH, B, C, D, A, 14, 23, 0xfde5380c); 412 OP (FH, A, B, C, D, 1, 4, 0xa4beea44); 413 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9); 414 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60); 415 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70); 416 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6); 417 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa); 418 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085); 419 OP (FH, B, C, D, A, 6, 23, 0x04881d05); 420 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039); 421 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5); 422 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8); 423 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665); 424 425 /* Round 4. */ 426 OP (FI, A, B, C, D, 0, 6, 0xf4292244); 427 OP (FI, D, A, B, C, 7, 10, 0x432aff97); 428 OP (FI, C, D, A, B, 14, 15, 0xab9423a7); 429 OP (FI, B, C, D, A, 5, 21, 0xfc93a039); 430 OP (FI, A, B, C, D, 12, 6, 0x655b59c3); 431 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92); 432 OP (FI, C, D, A, B, 10, 15, 0xffeff47d); 433 OP (FI, B, C, D, A, 1, 21, 0x85845dd1); 434 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f); 435 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0); 436 OP (FI, C, D, A, B, 6, 15, 0xa3014314); 437 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1); 438 OP (FI, A, B, C, D, 4, 6, 0xf7537e82); 439 OP (FI, D, A, B, C, 11, 10, 0xbd3af235); 440 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb); 441 OP (FI, B, C, D, A, 9, 21, 0xeb86d391); 442 443 /* Add the starting values of the context. */ 444 A += A_save; 445 B += B_save; 446 C += C_save; 447 D += D_save; 448 } 449 450 /* Put checksum in context given as argument. */ 451 ctx->A = A; 452 ctx->B = B; 453 ctx->C = C; 454 ctx->D = D; 455} 456