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) 1995-1997, 1999-2001, 2005-2006, 2008-2011 Free Software
5 This file is part of the GNU C Library.
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
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.
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. */
21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
31 #include <sys/types.h>
34 # include "unlocked-io.h"
39 # if __BYTE_ORDER == __BIG_ENDIAN
40 # define WORDS_BIGENDIAN 1
42 /* We need to keep the namespace clean so define the MD5 function
43 protected using leading __ . */
44 # define md5_init_ctx __md5_init_ctx
45 # define md5_process_block __md5_process_block
46 # define md5_process_bytes __md5_process_bytes
47 # define md5_finish_ctx __md5_finish_ctx
48 # define md5_read_ctx __md5_read_ctx
49 # define md5_stream __md5_stream
50 # define md5_buffer __md5_buffer
53 #ifdef WORDS_BIGENDIAN
55 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
60 #define BLOCKSIZE 32768
61 #if BLOCKSIZE % 64 != 0
62 # error "invalid BLOCKSIZE"
65 /* This array contains the bytes used to pad the buffer to the next
66 64-byte boundary. (RFC 1321, 3.1: Step 1) */
67 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
70 /* Initialize structure containing state of computation.
71 (RFC 1321, 3.3: Step 3) */
73 md5_init_ctx (struct md5_ctx *ctx)
80 ctx->total[0] = ctx->total[1] = 0;
84 /* Copy the 4 byte value from v into the memory location pointed to by *cp,
85 If your architecture allows unaligned access this is equivalent to
86 * (uint32_t *) cp = v */
88 set_uint32 (char *cp, uint32_t v)
90 memcpy (cp, &v, sizeof v);
93 /* Put result from CTX in first 16 bytes following RESBUF. The result
94 must be in little endian byte order. */
96 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
99 set_uint32 (r + 0 * sizeof ctx->A, SWAP (ctx->A));
100 set_uint32 (r + 1 * sizeof ctx->B, SWAP (ctx->B));
101 set_uint32 (r + 2 * sizeof ctx->C, SWAP (ctx->C));
102 set_uint32 (r + 3 * sizeof ctx->D, SWAP (ctx->D));
107 /* Process the remaining bytes in the internal buffer and the usual
108 prolog according to the standard and write the result to RESBUF. */
110 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
112 /* Take yet unprocessed bytes into account. */
113 uint32_t bytes = ctx->buflen;
114 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
116 /* Now count remaining bytes. */
117 ctx->total[0] += bytes;
118 if (ctx->total[0] < bytes)
121 /* Put the 64-bit file length in *bits* at the end of the buffer. */
122 ctx->buffer[size - 2] = SWAP (ctx->total[0] << 3);
123 ctx->buffer[size - 1] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
125 memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
127 /* Process last bytes. */
128 md5_process_block (ctx->buffer, size * 4, ctx);
130 return md5_read_ctx (ctx, resbuf);
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. */
137 md5_stream (FILE *stream, void *resblock)
142 char *buffer = malloc (BLOCKSIZE + 72);
146 /* Initialize the computation context. */
149 /* Iterate over full file contents. */
152 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
153 computation function processes the whole buffer so that with the
154 next round of the loop another block can be read. */
158 /* Read block. Take care for partial reads. */
161 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
165 if (sum == BLOCKSIZE)
170 /* Check for the error flag IFF N == 0, so that we don't
171 exit the loop after a partial read due to e.g., EAGAIN
178 goto process_partial_block;
181 /* We've read at least one byte, so ignore errors. But always
182 check for EOF, since feof may be true even though N > 0.
183 Otherwise, we could end up calling fread after EOF. */
185 goto process_partial_block;
188 /* Process buffer with BLOCKSIZE bytes. Note that
191 md5_process_block (buffer, BLOCKSIZE, &ctx);
194 process_partial_block:
196 /* Process any remaining bytes. */
198 md5_process_bytes (buffer, sum, &ctx);
200 /* Construct result in desired memory. */
201 md5_finish_ctx (&ctx, resblock);
206 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
207 result is always in little endian byte order, so that a byte-wise
208 output yields to the wanted ASCII representation of the message
211 md5_buffer (const char *buffer, size_t len, void *resblock)
215 /* Initialize the computation context. */
218 /* Process whole buffer but last len % 64 bytes. */
219 md5_process_bytes (buffer, len, &ctx);
221 /* Put result in desired memory area. */
222 return md5_finish_ctx (&ctx, resblock);
227 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
229 /* When we already have some bits in our internal buffer concatenate
230 both inputs first. */
231 if (ctx->buflen != 0)
233 size_t left_over = ctx->buflen;
234 size_t add = 128 - left_over > len ? len : 128 - left_over;
236 memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
239 if (ctx->buflen > 64)
241 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
244 /* The regions in the following copy operation cannot overlap. */
246 &((char *) ctx->buffer)[(left_over + add) & ~63],
250 buffer = (const char *) buffer + add;
254 /* Process available complete blocks. */
257 #if !_STRING_ARCH_unaligned
258 # define UNALIGNED_P(p) ((uintptr_t) (p) % alignof (uint32_t) != 0)
259 if (UNALIGNED_P (buffer))
262 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
263 buffer = (const char *) buffer + 64;
269 md5_process_block (buffer, len & ~63, ctx);
270 buffer = (const char *) buffer + (len & ~63);
275 /* Move remaining bytes in internal buffer. */
278 size_t left_over = ctx->buflen;
280 memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
284 md5_process_block (ctx->buffer, 64, ctx);
286 memcpy (ctx->buffer, &ctx->buffer[16], left_over);
288 ctx->buflen = left_over;
293 /* These are the four functions used in the four steps of the MD5 algorithm
294 and defined in the RFC 1321. The first function is a little bit optimized
295 (as found in Colin Plumbs public domain implementation). */
296 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
297 #define FF(b, c, d) (d ^ (b & (c ^ d)))
298 #define FG(b, c, d) FF (d, b, c)
299 #define FH(b, c, d) (b ^ c ^ d)
300 #define FI(b, c, d) (c ^ (b | ~d))
302 /* Process LEN bytes of BUFFER, accumulating context into CTX.
303 It is assumed that LEN % 64 == 0. */
306 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
308 uint32_t correct_words[16];
309 const uint32_t *words = buffer;
310 size_t nwords = len / sizeof (uint32_t);
311 const uint32_t *endp = words + nwords;
317 /* First increment the byte count. RFC 1321 specifies the possible
318 length of the file up to 2^64 bits. Here we only compute the
319 number of bytes. Do a double word increment. */
320 ctx->total[0] += len;
321 if (ctx->total[0] < len)
324 /* Process all bytes in the buffer with 64 bytes in each round of
328 uint32_t *cwp = correct_words;
334 /* First round: using the given function, the context and a constant
335 the next context is computed. Because the algorithms processing
336 unit is a 32-bit word and it is determined to work on words in
337 little endian byte order we perhaps have to change the byte order
338 before the computation. To reduce the work for the next steps
339 we store the swapped words in the array CORRECT_WORDS. */
341 #define OP(a, b, c, d, s, T) \
344 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
351 /* It is unfortunate that C does not provide an operator for
352 cyclic rotation. Hope the C compiler is smart enough. */
353 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
355 /* Before we start, one word to the strange constants.
356 They are defined in RFC 1321 as
358 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
360 Here is an equivalent invocation using Perl:
362 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
366 OP (A, B, C, D, 7, 0xd76aa478);
367 OP (D, A, B, C, 12, 0xe8c7b756);
368 OP (C, D, A, B, 17, 0x242070db);
369 OP (B, C, D, A, 22, 0xc1bdceee);
370 OP (A, B, C, D, 7, 0xf57c0faf);
371 OP (D, A, B, C, 12, 0x4787c62a);
372 OP (C, D, A, B, 17, 0xa8304613);
373 OP (B, C, D, A, 22, 0xfd469501);
374 OP (A, B, C, D, 7, 0x698098d8);
375 OP (D, A, B, C, 12, 0x8b44f7af);
376 OP (C, D, A, B, 17, 0xffff5bb1);
377 OP (B, C, D, A, 22, 0x895cd7be);
378 OP (A, B, C, D, 7, 0x6b901122);
379 OP (D, A, B, C, 12, 0xfd987193);
380 OP (C, D, A, B, 17, 0xa679438e);
381 OP (B, C, D, A, 22, 0x49b40821);
383 /* For the second to fourth round we have the possibly swapped words
384 in CORRECT_WORDS. Redefine the macro to take an additional first
385 argument specifying the function to use. */
387 #define OP(f, a, b, c, d, k, s, T) \
390 a += f (b, c, d) + correct_words[k] + T; \
397 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
398 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
399 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
400 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
401 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
402 OP (FG, D, A, B, C, 10, 9, 0x02441453);
403 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
404 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
405 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
406 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
407 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
408 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
409 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
410 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
411 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
412 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
415 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
416 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
417 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
418 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
419 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
420 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
421 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
422 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
423 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
424 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
425 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
426 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
427 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
428 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
429 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
430 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
433 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
434 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
435 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
436 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
437 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
438 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
439 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
440 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
441 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
442 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
443 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
444 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
445 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
446 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
447 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
448 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
450 /* Add the starting values of the context. */
457 /* Put checksum in context given as argument. */