source: coreutils/trunk/lib/md5.c@ 1649

Last change on this file since 1649 was 1648, checked in by Silvan Scherrer, 9 years ago

coreutils: update trunk to version 8.25
File size: 15.0 KB
Line 
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, 2008-2016 Free Software
4 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, see <http://www.gnu.org/licenses/>. */
19
20/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
21
22#include <config.h>
23
24#if HAVE_OPENSSL_MD5
25# define GL_OPENSSL_INLINE _GL_EXTERN_INLINE
26#endif
27#include "md5.h"
28
29#include <stdalign.h>
30#include <stdint.h>
31#include <stdlib.h>
32#include <string.h>
33#include <sys/types.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 32768
63#if BLOCKSIZE % 64 != 0
64# error "invalid BLOCKSIZE"
65#endif
66
67#if ! HAVE_OPENSSL_MD5
68/* This array contains the bytes used to pad the buffer to the next
69 64-byte boundary. (RFC 1321, 3.1: Step 1) */
70static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
71
72
73/* Initialize structure containing state of computation.
74 (RFC 1321, 3.3: Step 3) */
75void
76md5_init_ctx (struct md5_ctx *ctx)
77{
78 ctx->A = 0x67452301;
79 ctx->B = 0xefcdab89;
80 ctx->C = 0x98badcfe;
81 ctx->D = 0x10325476;
82
83 ctx->total[0] = ctx->total[1] = 0;
84 ctx->buflen = 0;
85}
86
87/* Copy the 4 byte value from v into the memory location pointed to by *cp,
88 If your architecture allows unaligned access this is equivalent to
89 * (uint32_t *) cp = v */
90static void
91set_uint32 (char *cp, uint32_t v)
92{
93 memcpy (cp, &v, sizeof v);
94}
95
96/* Put result from CTX in first 16 bytes following RESBUF. The result
97 must be in little endian byte order. */
98void *
99md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
100{
101 char *r = resbuf;
102 set_uint32 (r + 0 * sizeof ctx->A, SWAP (ctx->A));
103 set_uint32 (r + 1 * sizeof ctx->B, SWAP (ctx->B));
104 set_uint32 (r + 2 * sizeof ctx->C, SWAP (ctx->C));
105 set_uint32 (r + 3 * sizeof ctx->D, SWAP (ctx->D));
106
107 return resbuf;
108}
109
110/* Process the remaining bytes in the internal buffer and the usual
111 prolog according to the standard and write the result to RESBUF. */
112void *
113md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
114{
115 /* Take yet unprocessed bytes into account. */
116 uint32_t bytes = ctx->buflen;
117 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
118
119 /* Now count remaining bytes. */
120 ctx->total[0] += bytes;
121 if (ctx->total[0] < bytes)
122 ++ctx->total[1];
123
124 /* Put the 64-bit file length in *bits* at the end of the buffer. */
125 ctx->buffer[size - 2] = SWAP (ctx->total[0] << 3);
126 ctx->buffer[size - 1] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
127
128 memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
129
130 /* Process last bytes. */
131 md5_process_block (ctx->buffer, size * 4, ctx);
132
133 return md5_read_ctx (ctx, resbuf);
134}
135#endif
136
137/* Compute MD5 message digest for bytes read from STREAM. The
138 resulting message digest number will be written into the 16 bytes
139 beginning at RESBLOCK. */
140int
141md5_stream (FILE *stream, void *resblock)
142{
143 struct md5_ctx ctx;
144 size_t sum;
145
146 char *buffer = malloc (BLOCKSIZE + 72);
147 if (!buffer)
148 return 1;
149
150 /* Initialize the computation context. */
151 md5_init_ctx (&ctx);
152
153 /* Iterate over full file contents. */
154 while (1)
155 {
156 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
157 computation function processes the whole buffer so that with the
158 next round of the loop another block can be read. */
159 size_t n;
160 sum = 0;
161
162 /* Read block. Take care for partial reads. */
163 while (1)
164 {
165 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
166
167 sum += n;
168
169 if (sum == BLOCKSIZE)
170 break;
171
172 if (n == 0)
173 {
174 /* Check for the error flag IFF N == 0, so that we don't
175 exit the loop after a partial read due to e.g., EAGAIN
176 or EWOULDBLOCK. */
177 if (ferror (stream))
178 {
179 free (buffer);
180 return 1;
181 }
182 goto process_partial_block;
183 }
184
185 /* We've read at least one byte, so ignore errors. But always
186 check for EOF, since feof may be true even though N > 0.
187 Otherwise, we could end up calling fread after EOF. */
188 if (feof (stream))
189 goto process_partial_block;
190 }
191
192 /* Process buffer with BLOCKSIZE bytes. Note that
193 BLOCKSIZE % 64 == 0
194 */
195 md5_process_block (buffer, BLOCKSIZE, &ctx);
196 }
197
198process_partial_block:
199
200 /* Process any remaining bytes. */
201 if (sum > 0)
202 md5_process_bytes (buffer, sum, &ctx);
203
204 /* Construct result in desired memory. */
205 md5_finish_ctx (&ctx, resblock);
206 free (buffer);
207 return 0;
208}
209
210#if ! HAVE_OPENSSL_MD5
211/* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
212 result is always in little endian byte order, so that a byte-wise
213 output yields to the wanted ASCII representation of the message
214 digest. */
215void *
216md5_buffer (const char *buffer, size_t len, void *resblock)
217{
218 struct md5_ctx ctx;
219
220 /* Initialize the computation context. */
221 md5_init_ctx (&ctx);
222
223 /* Process whole buffer but last len % 64 bytes. */
224 md5_process_bytes (buffer, len, &ctx);
225
226 /* Put result in desired memory area. */
227 return md5_finish_ctx (&ctx, resblock);
228}
229
230
231void
232md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
233{
234 /* When we already have some bits in our internal buffer concatenate
235 both inputs first. */
236 if (ctx->buflen != 0)
237 {
238 size_t left_over = ctx->buflen;
239 size_t add = 128 - left_over > len ? len : 128 - left_over;
240
241 memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
242 ctx->buflen += add;
243
244 if (ctx->buflen > 64)
245 {
246 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
247
248 ctx->buflen &= 63;
249 /* The regions in the following copy operation cannot overlap. */
250 memcpy (ctx->buffer,
251 &((char *) ctx->buffer)[(left_over + add) & ~63],
252 ctx->buflen);
253 }
254
255 buffer = (const char *) buffer + add;
256 len -= add;
257 }
258
259 /* Process available complete blocks. */
260 if (len >= 64)
261 {
262#if !_STRING_ARCH_unaligned
263# define UNALIGNED_P(p) ((uintptr_t) (p) % alignof (uint32_t) != 0)
264 if (UNALIGNED_P (buffer))
265 while (len > 64)
266 {
267 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
268 buffer = (const char *) buffer + 64;
269 len -= 64;
270 }
271 else
272#endif
273 {
274 md5_process_block (buffer, len & ~63, ctx);
275 buffer = (const char *) buffer + (len & ~63);
276 len &= 63;
277 }
278 }
279
280 /* Move remaining bytes in internal buffer. */
281 if (len > 0)
282 {
283 size_t left_over = ctx->buflen;
284
285 memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
286 left_over += len;
287 if (left_over >= 64)
288 {
289 md5_process_block (ctx->buffer, 64, ctx);
290 left_over -= 64;
291 memcpy (ctx->buffer, &ctx->buffer[16], left_over);
292 }
293 ctx->buflen = left_over;
294 }
295}
296
297
298/* These are the four functions used in the four steps of the MD5 algorithm
299 and defined in the RFC 1321. The first function is a little bit optimized
300 (as found in Colin Plumbs public domain implementation). */
301/* #define FF(b, c, d) ((b & c) | (~b & d)) */
302#define FF(b, c, d) (d ^ (b & (c ^ d)))
303#define FG(b, c, d) FF (d, b, c)
304#define FH(b, c, d) (b ^ c ^ d)
305#define FI(b, c, d) (c ^ (b | ~d))
306
307/* Process LEN bytes of BUFFER, accumulating context into CTX.
308 It is assumed that LEN % 64 == 0. */
309
310void
311md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
312{
313 uint32_t correct_words[16];
314 const uint32_t *words = buffer;
315 size_t nwords = len / sizeof (uint32_t);
316 const uint32_t *endp = words + nwords;
317 uint32_t A = ctx->A;
318 uint32_t B = ctx->B;
319 uint32_t C = ctx->C;
320 uint32_t D = ctx->D;
321 uint32_t lolen = len;
322
323 /* First increment the byte count. RFC 1321 specifies the possible
324 length of the file up to 2^64 bits. Here we only compute the
325 number of bytes. Do a double word increment. */
326 ctx->total[0] += lolen;
327 ctx->total[1] += (len >> 31 >> 1) + (ctx->total[0] < lolen);
328
329 /* Process all bytes in the buffer with 64 bytes in each round of
330 the loop. */
331 while (words < endp)
332 {
333 uint32_t *cwp = correct_words;
334 uint32_t A_save = A;
335 uint32_t B_save = B;
336 uint32_t C_save = C;
337 uint32_t D_save = D;
338
339 /* First round: using the given function, the context and a constant
340 the next context is computed. Because the algorithms processing
341 unit is a 32-bit word and it is determined to work on words in
342 little endian byte order we perhaps have to change the byte order
343 before the computation. To reduce the work for the next steps
344 we store the swapped words in the array CORRECT_WORDS. */
345
346#define OP(a, b, c, d, s, T) \
347 do \
348 { \
349 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
350 ++words; \
351 CYCLIC (a, s); \
352 a += b; \
353 } \
354 while (0)
355
356 /* It is unfortunate that C does not provide an operator for
357 cyclic rotation. Hope the C compiler is smart enough. */
358#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
359
360 /* Before we start, one word to the strange constants.
361 They are defined in RFC 1321 as
362
363 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
364
365 Here is an equivalent invocation using Perl:
366
367 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
368 */
369
370 /* Round 1. */
371 OP (A, B, C, D, 7, 0xd76aa478);
372 OP (D, A, B, C, 12, 0xe8c7b756);
373 OP (C, D, A, B, 17, 0x242070db);
374 OP (B, C, D, A, 22, 0xc1bdceee);
375 OP (A, B, C, D, 7, 0xf57c0faf);
376 OP (D, A, B, C, 12, 0x4787c62a);
377 OP (C, D, A, B, 17, 0xa8304613);
378 OP (B, C, D, A, 22, 0xfd469501);
379 OP (A, B, C, D, 7, 0x698098d8);
380 OP (D, A, B, C, 12, 0x8b44f7af);
381 OP (C, D, A, B, 17, 0xffff5bb1);
382 OP (B, C, D, A, 22, 0x895cd7be);
383 OP (A, B, C, D, 7, 0x6b901122);
384 OP (D, A, B, C, 12, 0xfd987193);
385 OP (C, D, A, B, 17, 0xa679438e);
386 OP (B, C, D, A, 22, 0x49b40821);
387
388 /* For the second to fourth round we have the possibly swapped words
389 in CORRECT_WORDS. Redefine the macro to take an additional first
390 argument specifying the function to use. */
391#undef OP
392#define OP(f, a, b, c, d, k, s, T) \
393 do \
394 { \
395 a += f (b, c, d) + correct_words[k] + T; \
396 CYCLIC (a, s); \
397 a += b; \
398 } \
399 while (0)
400
401 /* Round 2. */
402 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
403 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
404 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
405 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
406 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
407 OP (FG, D, A, B, C, 10, 9, 0x02441453);
408 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
409 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
410 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
411 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
412 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
413 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
414 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
415 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
416 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
417 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
418
419 /* Round 3. */
420 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
421 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
422 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
423 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
424 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
425 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
426 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
427 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
428 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
429 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
430 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
431 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
432 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
433 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
434 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
435 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
436
437 /* Round 4. */
438 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
439 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
440 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
441 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
442 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
443 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
444 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
445 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
446 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
447 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
448 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
449 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
450 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
451 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
452 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
453 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
454
455 /* Add the starting values of the context. */
456 A += A_save;
457 B += B_save;
458 C += C_save;
459 D += D_save;
460 }
461
462 /* Put checksum in context given as argument. */
463 ctx->A = A;
464 ctx->B = B;
465 ctx->C = C;
466 ctx->D = D;
467}
468#endif
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