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
4 Free Software Foundation, Inc.
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. */
32 #include <sys/types.h>
35 # include "unlocked-io.h"
40 # if __BYTE_ORDER == __BIG_ENDIAN
41 # define WORDS_BIGENDIAN 1
43 /* We need to keep the namespace clean so define the MD5 function
44 protected using leading __ . */
45 # define md5_init_ctx __md5_init_ctx
46 # define md5_process_block __md5_process_block
47 # define md5_process_bytes __md5_process_bytes
48 # define md5_finish_ctx __md5_finish_ctx
49 # define md5_read_ctx __md5_read_ctx
50 # define md5_stream __md5_stream
51 # define md5_buffer __md5_buffer
54 #ifdef WORDS_BIGENDIAN
56 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
61 #define BLOCKSIZE 4096
62 #if BLOCKSIZE % 64 != 0
63 # error "invalid BLOCKSIZE"
66 /* This array contains the bytes used to pad the buffer to the next
67 64-byte boundary. (RFC 1321, 3.1: Step 1) */
68 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
71 /* Initialize structure containing state of computation.
72 (RFC 1321, 3.3: Step 3) */
74 md5_init_ctx (struct md5_ctx *ctx)
81 ctx->total[0] = ctx->total[1] = 0;
85 /* Put result from CTX in first 16 bytes following RESBUF. The result
86 must be in little endian byte order.
88 IMPORTANT: On some systems it is required that RESBUF is correctly
89 aligned for a 32 bits value. */
91 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
93 ((uint32_t *) resbuf)[0] = SWAP (ctx->A);
94 ((uint32_t *) resbuf)[1] = SWAP (ctx->B);
95 ((uint32_t *) resbuf)[2] = SWAP (ctx->C);
96 ((uint32_t *) resbuf)[3] = SWAP (ctx->D);
101 /* Process the remaining bytes in the internal buffer and the usual
102 prolog according to the standard and write the result to RESBUF.
104 IMPORTANT: On some systems it is required that RESBUF is correctly
105 aligned for a 32 bits value. */
107 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
109 /* Take yet unprocessed bytes into account. */
110 uint32_t bytes = ctx->buflen;
113 /* Now count remaining bytes. */
114 ctx->total[0] += bytes;
115 if (ctx->total[0] < bytes)
118 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
119 memcpy (&ctx->buffer[bytes], fillbuf, pad);
121 /* Put the 64-bit file length in *bits* at the end of the buffer. */
122 *(uint32_t *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
123 *(uint32_t *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
124 (ctx->total[0] >> 29));
126 /* Process last bytes. */
127 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
129 return md5_read_ctx (ctx, resbuf);
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. */
136 md5_stream (FILE *stream, void *resblock)
139 char buffer[BLOCKSIZE + 72];
142 /* Initialize the computation context. */
145 /* Iterate over full file contents. */
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. */
154 /* Read block. Take care for partial reads. */
157 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
161 if (sum == BLOCKSIZE)
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
171 goto process_partial_block;
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. */
178 goto process_partial_block;
181 /* Process buffer with BLOCKSIZE bytes. Note that
184 md5_process_block (buffer, BLOCKSIZE, &ctx);
187 process_partial_block:;
189 /* Process any remaining bytes. */
191 md5_process_bytes (buffer, sum, &ctx);
193 /* Construct result in desired memory. */
194 md5_finish_ctx (&ctx, resblock);
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
203 md5_buffer (const char *buffer, size_t len, void *resblock)
207 /* Initialize the computation context. */
210 /* Process whole buffer but last len % 64 bytes. */
211 md5_process_bytes (buffer, len, &ctx);
213 /* Put result in desired memory area. */
214 return md5_finish_ctx (&ctx, resblock);
219 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
221 /* When we already have some bits in our internal buffer concatenate
222 both inputs first. */
223 if (ctx->buflen != 0)
225 size_t left_over = ctx->buflen;
226 size_t add = 128 - left_over > len ? len : 128 - left_over;
228 memcpy (&ctx->buffer[left_over], buffer, add);
231 if (ctx->buflen > 64)
233 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
236 /* The regions in the following copy operation cannot overlap. */
237 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
241 buffer = (const char *) buffer + add;
245 /* Process available complete blocks. */
248 #if !_STRING_ARCH_unaligned
249 /* To check alignment gcc has an appropriate operator. Other
252 # define UNALIGNED_P(p) (((uintptr_t) p) % __alignof__ (uint32_t) != 0)
254 # define alignof(type) offsetof (struct { char c; type x; }, x)
255 # define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0)
257 if (UNALIGNED_P (buffer))
260 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
261 buffer = (const char *) buffer + 64;
267 md5_process_block (buffer, len & ~63, ctx);
268 buffer = (const char *) buffer + (len & ~63);
273 /* Move remaining bytes in internal buffer. */
276 size_t left_over = ctx->buflen;
278 memcpy (&ctx->buffer[left_over], buffer, len);
282 md5_process_block (ctx->buffer, 64, ctx);
284 memcpy (ctx->buffer, &ctx->buffer[64], left_over);
286 ctx->buflen = left_over;
291 /* These are the four functions used in the four steps of the MD5 algorithm
292 and defined in the RFC 1321. The first function is a little bit optimized
293 (as found in Colin Plumbs public domain implementation). */
294 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
295 #define FF(b, c, d) (d ^ (b & (c ^ d)))
296 #define FG(b, c, d) FF (d, b, c)
297 #define FH(b, c, d) (b ^ c ^ d)
298 #define FI(b, c, d) (c ^ (b | ~d))
300 /* Process LEN bytes of BUFFER, accumulating context into CTX.
301 It is assumed that LEN % 64 == 0. */
304 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
306 uint32_t correct_words[16];
307 const uint32_t *words = buffer;
308 size_t nwords = len / sizeof (uint32_t);
309 const uint32_t *endp = words + nwords;
315 /* First increment the byte count. RFC 1321 specifies the possible
316 length of the file up to 2^64 bits. Here we only compute the
317 number of bytes. Do a double word increment. */
318 ctx->total[0] += len;
319 if (ctx->total[0] < len)
322 /* Process all bytes in the buffer with 64 bytes in each round of
326 uint32_t *cwp = correct_words;
332 /* First round: using the given function, the context and a constant
333 the next context is computed. Because the algorithms processing
334 unit is a 32-bit word and it is determined to work on words in
335 little endian byte order we perhaps have to change the byte order
336 before the computation. To reduce the work for the next steps
337 we store the swapped words in the array CORRECT_WORDS. */
339 #define OP(a, b, c, d, s, T) \
342 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
349 /* It is unfortunate that C does not provide an operator for
350 cyclic rotation. Hope the C compiler is smart enough. */
351 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
353 /* Before we start, one word to the strange constants.
354 They are defined in RFC 1321 as
356 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
358 Here is an equivalent invocation using Perl:
360 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
364 OP (A, B, C, D, 7, 0xd76aa478);
365 OP (D, A, B, C, 12, 0xe8c7b756);
366 OP (C, D, A, B, 17, 0x242070db);
367 OP (B, C, D, A, 22, 0xc1bdceee);
368 OP (A, B, C, D, 7, 0xf57c0faf);
369 OP (D, A, B, C, 12, 0x4787c62a);
370 OP (C, D, A, B, 17, 0xa8304613);
371 OP (B, C, D, A, 22, 0xfd469501);
372 OP (A, B, C, D, 7, 0x698098d8);
373 OP (D, A, B, C, 12, 0x8b44f7af);
374 OP (C, D, A, B, 17, 0xffff5bb1);
375 OP (B, C, D, A, 22, 0x895cd7be);
376 OP (A, B, C, D, 7, 0x6b901122);
377 OP (D, A, B, C, 12, 0xfd987193);
378 OP (C, D, A, B, 17, 0xa679438e);
379 OP (B, C, D, A, 22, 0x49b40821);
381 /* For the second to fourth round we have the possibly swapped words
382 in CORRECT_WORDS. Redefine the macro to take an additional first
383 argument specifying the function to use. */
385 #define OP(f, a, b, c, d, k, s, T) \
388 a += f (b, c, d) + correct_words[k] + T; \
395 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
396 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
397 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
398 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
399 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
400 OP (FG, D, A, B, C, 10, 9, 0x02441453);
401 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
402 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
403 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
404 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
405 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
406 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
407 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
408 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
409 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
410 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
413 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
414 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
415 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
416 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
417 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
418 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
419 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
420 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
421 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
422 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
423 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
424 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
425 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
426 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
427 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
428 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
431 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
432 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
433 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
434 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
435 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
436 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
437 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
438 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
439 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
440 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
441 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
442 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
443 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
444 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
445 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
446 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
448 /* Add the starting values of the context. */
455 /* Put checksum in context given as argument. */