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, 2008-2012 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 3, 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, see <http://www.gnu.org/licenses/>. */
20 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
30 #include <sys/types.h>
33 # include "unlocked-io.h"
38 # if __BYTE_ORDER == __BIG_ENDIAN
39 # define WORDS_BIGENDIAN 1
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
52 #ifdef WORDS_BIGENDIAN
54 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
59 #define BLOCKSIZE 32768
60 #if BLOCKSIZE % 64 != 0
61 # error "invalid BLOCKSIZE"
64 /* This array contains the bytes used to pad the buffer to the next
65 64-byte boundary. (RFC 1321, 3.1: Step 1) */
66 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
69 /* Initialize structure containing state of computation.
70 (RFC 1321, 3.3: Step 3) */
72 md5_init_ctx (struct md5_ctx *ctx)
79 ctx->total[0] = ctx->total[1] = 0;
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 */
87 set_uint32 (char *cp, uint32_t v)
89 memcpy (cp, &v, sizeof v);
92 /* Put result from CTX in first 16 bytes following RESBUF. The result
93 must be in little endian byte order. */
95 md5_read_ctx (const struct md5_ctx *ctx, void *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));
106 /* Process the remaining bytes in the internal buffer and the usual
107 prolog according to the standard and write the result to RESBUF. */
109 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
111 /* Take yet unprocessed bytes into account. */
112 uint32_t bytes = ctx->buflen;
113 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
115 /* Now count remaining bytes. */
116 ctx->total[0] += bytes;
117 if (ctx->total[0] < bytes)
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));
124 memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
126 /* Process last bytes. */
127 md5_process_block (ctx->buffer, size * 4, ctx);
129 return md5_read_ctx (ctx, resbuf);
132 #if 0 /* Not needed by GnuTLS, and it has a large stack frame. */
134 /* Compute MD5 message digest for bytes read from STREAM. The
135 resulting message digest number will be written into the 16 bytes
136 beginning at RESBLOCK. */
138 md5_stream (FILE *stream, void *resblock)
143 char *buffer = malloc (BLOCKSIZE + 72);
147 /* Initialize the computation context. */
150 /* Iterate over full file contents. */
153 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
154 computation function processes the whole buffer so that with the
155 next round of the loop another block can be read. */
159 /* Read block. Take care for partial reads. */
162 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
166 if (sum == BLOCKSIZE)
171 /* Check for the error flag IFF N == 0, so that we don't
172 exit the loop after a partial read due to e.g., EAGAIN
179 goto process_partial_block;
182 /* We've read at least one byte, so ignore errors. But always
183 check for EOF, since feof may be true even though N > 0.
184 Otherwise, we could end up calling fread after EOF. */
186 goto process_partial_block;
189 /* Process buffer with BLOCKSIZE bytes. Note that
192 md5_process_block (buffer, BLOCKSIZE, &ctx);
195 process_partial_block:
197 /* Process any remaining bytes. */
199 md5_process_bytes (buffer, sum, &ctx);
201 /* Construct result in desired memory. */
202 md5_finish_ctx (&ctx, resblock);
208 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
209 result is always in little endian byte order, so that a byte-wise
210 output yields to the wanted ASCII representation of the message
213 md5_buffer (const char *buffer, size_t len, void *resblock)
217 /* Initialize the computation context. */
220 /* Process whole buffer but last len % 64 bytes. */
221 md5_process_bytes (buffer, len, &ctx);
223 /* Put result in desired memory area. */
224 return md5_finish_ctx (&ctx, resblock);
229 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
231 /* When we already have some bits in our internal buffer concatenate
232 both inputs first. */
233 if (ctx->buflen != 0)
235 size_t left_over = ctx->buflen;
236 size_t add = 128 - left_over > len ? len : 128 - left_over;
238 memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
241 if (ctx->buflen > 64)
243 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
246 /* The regions in the following copy operation cannot overlap. */
248 &((char *) ctx->buffer)[(left_over + add) & ~63],
252 buffer = (const char *) buffer + add;
256 /* Process available complete blocks. */
259 #if !_STRING_ARCH_unaligned
260 # define UNALIGNED_P(p) ((uintptr_t) (p) % alignof (uint32_t) != 0)
261 if (UNALIGNED_P (buffer))
264 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
265 buffer = (const char *) buffer + 64;
271 md5_process_block (buffer, len & ~63, ctx);
272 buffer = (const char *) buffer + (len & ~63);
277 /* Move remaining bytes in internal buffer. */
280 size_t left_over = ctx->buflen;
282 memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
286 md5_process_block (ctx->buffer, 64, ctx);
288 memcpy (ctx->buffer, &ctx->buffer[16], left_over);
290 ctx->buflen = left_over;
295 /* These are the four functions used in the four steps of the MD5 algorithm
296 and defined in the RFC 1321. The first function is a little bit optimized
297 (as found in Colin Plumbs public domain implementation). */
298 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
299 #define FF(b, c, d) (d ^ (b & (c ^ d)))
300 #define FG(b, c, d) FF (d, b, c)
301 #define FH(b, c, d) (b ^ c ^ d)
302 #define FI(b, c, d) (c ^ (b | ~d))
304 /* Process LEN bytes of BUFFER, accumulating context into CTX.
305 It is assumed that LEN % 64 == 0. */
308 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
310 uint32_t correct_words[16];
311 const uint32_t *words = buffer;
312 size_t nwords = len / sizeof (uint32_t);
313 const uint32_t *endp = words + nwords;
319 /* First increment the byte count. RFC 1321 specifies the possible
320 length of the file up to 2^64 bits. Here we only compute the
321 number of bytes. Do a double word increment. */
322 ctx->total[0] += len;
323 if (ctx->total[0] < len)
326 /* Process all bytes in the buffer with 64 bytes in each round of
330 uint32_t *cwp = correct_words;
336 /* First round: using the given function, the context and a constant
337 the next context is computed. Because the algorithms processing
338 unit is a 32-bit word and it is determined to work on words in
339 little endian byte order we perhaps have to change the byte order
340 before the computation. To reduce the work for the next steps
341 we store the swapped words in the array CORRECT_WORDS. */
343 #define OP(a, b, c, d, s, T) \
346 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
353 /* It is unfortunate that C does not provide an operator for
354 cyclic rotation. Hope the C compiler is smart enough. */
355 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
357 /* Before we start, one word to the strange constants.
358 They are defined in RFC 1321 as
360 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
362 Here is an equivalent invocation using Perl:
364 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
368 OP (A, B, C, D, 7, 0xd76aa478);
369 OP (D, A, B, C, 12, 0xe8c7b756);
370 OP (C, D, A, B, 17, 0x242070db);
371 OP (B, C, D, A, 22, 0xc1bdceee);
372 OP (A, B, C, D, 7, 0xf57c0faf);
373 OP (D, A, B, C, 12, 0x4787c62a);
374 OP (C, D, A, B, 17, 0xa8304613);
375 OP (B, C, D, A, 22, 0xfd469501);
376 OP (A, B, C, D, 7, 0x698098d8);
377 OP (D, A, B, C, 12, 0x8b44f7af);
378 OP (C, D, A, B, 17, 0xffff5bb1);
379 OP (B, C, D, A, 22, 0x895cd7be);
380 OP (A, B, C, D, 7, 0x6b901122);
381 OP (D, A, B, C, 12, 0xfd987193);
382 OP (C, D, A, B, 17, 0xa679438e);
383 OP (B, C, D, A, 22, 0x49b40821);
385 /* For the second to fourth round we have the possibly swapped words
386 in CORRECT_WORDS. Redefine the macro to take an additional first
387 argument specifying the function to use. */
389 #define OP(f, a, b, c, d, k, s, T) \
392 a += f (b, c, d) + correct_words[k] + T; \
399 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
400 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
401 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
402 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
403 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
404 OP (FG, D, A, B, C, 10, 9, 0x02441453);
405 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
406 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
407 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
408 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
409 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
410 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
411 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
412 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
413 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
414 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
417 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
418 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
419 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
420 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
421 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
422 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
423 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
424 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
425 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
426 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
427 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
428 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
429 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
430 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
431 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
432 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
435 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
436 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
437 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
438 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
439 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
440 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
441 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
442 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
443 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
444 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
445 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
446 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
447 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
448 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
449 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
450 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
452 /* Add the starting values of the context. */
459 /* Put checksum in context given as argument. */