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, 2001, 2003, 2004, 2005 Free Software Foundation, Inc. 4 NOTE: The canonical source of this file is maintained with the GNU C 5 Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu. 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 2, 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#include <sys/cdefs.h> 21__RCSID("$NetBSD: md5.c,v 1.2 2016/05/17 14:00:09 christos Exp $"); 22 23 24/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */ 25 26#ifdef HAVE_CONFIG_H 27# include <config.h> 28#endif 29 30#include "md5.h" 31 32#include <stddef.h> 33#include <string.h> 34 35#if USE_UNLOCKED_IO 36# include "unlocked-io.h" 37#endif 38 39#ifdef _LIBC 40# include <endian.h> 41# if __BYTE_ORDER == __BIG_ENDIAN 42# define WORDS_BIGENDIAN 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#ifdef WORDS_BIGENDIAN 56# define SWAP(n) \ 57 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) 58#else 59# define SWAP(n) (n) 60#endif 61 62#define BLOCKSIZE 4096 63#if BLOCKSIZE % 64 != 0 64# error "invalid BLOCKSIZE" 65#endif 66 67/* This array contains the bytes used to pad the buffer to the next 68 64-byte boundary. (RFC 1321, 3.1: Step 1) */ 69static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; 70 71 72/* Initialize structure containing state of computation. 73 (RFC 1321, 3.3: Step 3) */ 74void 75md5_init_ctx (struct md5_ctx *ctx) 76{ 77 ctx->A = 0x67452301; 78 ctx->B = 0xefcdab89; 79 ctx->C = 0x98badcfe; 80 ctx->D = 0x10325476; 81 82 ctx->total[0] = ctx->total[1] = 0; 83 ctx->buflen = 0; 84} 85 86/* Put result from CTX in first 16 bytes following RESBUF. The result 87 must be in little endian byte order. 88 89 IMPORTANT: On some systems it is required that RESBUF is correctly 90 aligned for a 32 bits value. */ 91void * 92md5_read_ctx (const struct md5_ctx *ctx, 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 (struct md5_ctx *ctx, void *resbuf) 109{ 110 /* Take yet unprocessed bytes into account. */ 111 md5_uint32 bytes = ctx->buflen; 112 size_t pad; 113 114 /* Now count remaining bytes. */ 115 ctx->total[0] += bytes; 116 if (ctx->total[0] < bytes) 117 ++ctx->total[1]; 118 119 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; 120 memcpy (&ctx->buffer[bytes], fillbuf, pad); 121 122 /* Put the 64-bit file length in *bits* at the end of the buffer. */ 123 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3); 124 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) | 125 (ctx->total[0] >> 29)); 126 127 /* Process last bytes. */ 128 md5_process_block (ctx->buffer, bytes + pad + 8, ctx); 129 130 return md5_read_ctx (ctx, resbuf); 131} 132 133/* Compute MD5 message digest for bytes read from STREAM. The 134 resulting message digest number will be written into the 16 bytes 135 beginning at RESBLOCK. */ 136int 137md5_stream (FILE *stream, void *resblock) 138{ 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 while (1) 157 { 158 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); 159 160 sum += n; 161 162 if (sum == BLOCKSIZE) 163 break; 164 165 if (n == 0) 166 { 167 /* Check for the error flag IFF N == 0, so that we don't 168 exit the loop after a partial read due to e.g., EAGAIN 169 or EWOULDBLOCK. */ 170 if (ferror (stream)) 171 return 1; 172 goto process_partial_block; 173 } 174 175 /* We've read at least one byte, so ignore errors. But always 176 check for EOF, since feof may be true even though N > 0. 177 Otherwise, we could end up calling fread after EOF. */ 178 if (feof (stream)) 179 goto process_partial_block; 180 } 181 182 /* Process buffer with BLOCKSIZE bytes. Note that 183 BLOCKSIZE % 64 == 0 184 */ 185 md5_process_block (buffer, BLOCKSIZE, &ctx); 186 } 187 188 process_partial_block:; 189 190 /* Process any remaining bytes. */ 191 if (sum > 0) 192 md5_process_bytes (buffer, sum, &ctx); 193 194 /* Construct result in desired memory. */ 195 md5_finish_ctx (&ctx, resblock); 196 return 0; 197} 198 199/* Compute MD5 message digest for LEN bytes beginning at BUFFER. The 200 result is always in little endian byte order, so that a byte-wise 201 output yields to the wanted ASCII representation of the message 202 digest. */ 203void * 204md5_buffer (const char *buffer, size_t len, void *resblock) 205{ 206 struct md5_ctx ctx; 207 208 /* Initialize the computation context. */ 209 md5_init_ctx (&ctx); 210 211 /* Process whole buffer but last len % 64 bytes. */ 212 md5_process_bytes (buffer, len, &ctx); 213 214 /* Put result in desired memory area. */ 215 return md5_finish_ctx (&ctx, resblock); 216} 217 218 219void 220md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx) 221{ 222 /* When we already have some bits in our internal buffer concatenate 223 both inputs first. */ 224 if (ctx->buflen != 0) 225 { 226 size_t left_over = ctx->buflen; 227 size_t add = 128 - left_over > len ? len : 128 - left_over; 228 229 memcpy (&ctx->buffer[left_over], buffer, add); 230 ctx->buflen += add; 231 232 if (ctx->buflen > 64) 233 { 234 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx); 235 236 ctx->buflen &= 63; 237 /* The regions in the following copy operation cannot overlap. */ 238 memcpy (ctx->buffer, &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 (md5_uint32) != 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 (&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[64], 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 md5_uint32 correct_words[16]; 302 const md5_uint32 *words = buffer; 303 size_t nwords = len / sizeof (md5_uint32); 304 const md5_uint32 *endp = words + nwords; 305 md5_uint32 A = ctx->A; 306 md5_uint32 B = ctx->B; 307 md5_uint32 C = ctx->C; 308 md5_uint32 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 md5_uint32 *cwp = correct_words; 322 md5_uint32 A_save = A; 323 md5_uint32 B_save = B; 324 md5_uint32 C_save = C; 325 md5_uint32 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