QOF: md5.c Source File

QOF 0.7.5

md5.c
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 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
21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
22
23 #ifdef HAVE_CONFIG_H
24 # include <config.h>
25 #endif
26
27 #include <sys/types.h>
28
29 #if STDC_HEADERS || defined _LIBC
30 # include <stdlib.h>
31 # include <string.h>
32 #else
33 # ifndef HAVE_MEMCPY
34 #include <string.h>
35 # define memcpy(d, s, n) bcopy ((s), (d), (n))
36 # endif
37 #endif
38
39 #include "md5.h"
40
41 #ifdef _LIBC
42 # include <endian.h>
43 # if __BYTE_ORDER == __BIG_ENDIAN
44 # define WORDS_BIGENDIAN 1
45 # endif
46 #endif
47
48 #ifdef WORDS_BIGENDIAN
49 # define SWAP(n) \
50 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
51 #else
52 # define SWAP(n) (n)
53 #endif
54
55
56 /* This array contains the bytes used to pad the buffer to the next
57 64-byte boundary. (RFC 1321, 3.1: Step 1) */
58 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
59
60
61 /* Initialize structure containing state of computation.
62 (RFC 1321, 3.3: Step 3) */
63 void
64 md5_init_ctx (ctx)
65 struct md5_ctx *ctx;
66 {
67 ctx->A = 0x67452301;
68 ctx->B = 0xefcdab89;
69 ctx->C = 0x98badcfe;
70 ctx->D = 0x10325476;
71
72 ctx->total[0] = ctx->total[1] = 0;
73 ctx->buflen = 0;
74 }
75
76 /* Put result from CTX in first 16 bytes following RESBUF. The result
77 must be in little endian byte order.
78
79 IMPORTANT: On some systems it is required that RESBUF is correctly
80 aligned for a 32 bits value. */
81 void *
82 md5_read_ctx (ctx, resbuf)
83 const struct md5_ctx *ctx;
84 void *resbuf;
85 {
86 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
87 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
88 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
89 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
90
91 return resbuf;
92 }
93
94 /* Process the remaining bytes in the internal buffer and the usual
95 prolog according to the standard and write the result to RESBUF.
96
97 IMPORTANT: On some systems it is required that RESBUF is correctly
98 aligned for a 32 bits value. */
99 void *
100 md5_finish_ctx (ctx, resbuf)
101 struct md5_ctx *ctx;
102 void *resbuf;
103 {
104 /* Take yet unprocessed bytes into account. */
105 md5_uint32 bytes = ctx->buflen;
106 size_t pad;
107
108 /* Now count remaining bytes. */
109 ctx->total[0] += bytes;
110 if (ctx->total[0] < bytes)
111 ++ctx->total[1];
112
113 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
114 memcpy (&ctx->buffer[bytes], fillbuf, pad);
115
116 /* Put the 64-bit file length in *bits* at the end of the buffer. */
117 *(md5_uint32 *) & ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
118 *(md5_uint32 *) & ctx->buffer[bytes + pad + 4] =
119 SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
120
121 /* Process last bytes. */
122 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
123
124 return md5_read_ctx (ctx, resbuf);
125 }
126
127 /* Compute MD5 message digest for bytes read from STREAM. The
128 resulting message digest number will be written into the 16 bytes
129 beginning at RESBLOCK. */
130 int
131 md5_stream (stream, resblock)
132 FILE *stream;
133 void *resblock;
134 {
135 /* Important: BLOCKSIZE must be a multiple of 64. */
136 #define BLOCKSIZE 4096
137 struct md5_ctx ctx;
138 char buffer[BLOCKSIZE + 72];
139 size_t sum;
140
141 /* Initialize the computation context. */
142 md5_init_ctx (&ctx);
143
144 /* Iterate over full file contents. */
145 while (1)
146 {
147 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
148 computation function processes the whole buffer so that with the
149 next round of the loop another block can be read. */
150 size_t n;
151 sum = 0;
152
153 /* Read block. Take care for partial reads. */
154 do
155 {
156 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
157
158 sum += n;
159 }
160 while (sum < BLOCKSIZE && n != 0);
161 if (n == 0 && ferror (stream))
162 return 1;
163
164 /* If end of file is reached, end the loop. */
165 if (n == 0)
166 break;
167
168 /* Process buffer with BLOCKSIZE bytes. Note that
169 BLOCKSIZE % 64 == 0
170 */
171 md5_process_block (buffer, BLOCKSIZE, &ctx);
172 }
173
174 /* Add the last bytes if necessary. */
175 if (sum > 0)
176 md5_process_bytes (buffer, sum, &ctx);
177
178 /* Construct result in desired memory. */
179 md5_finish_ctx (&ctx, resblock);
180 return 0;
181 }
182
183 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
184 result is always in little endian byte order, so that a byte-wise
185 output yields to the wanted ASCII representation of the message
186 digest. */
187 void *
188 md5_buffer (buffer, len, resblock)
189 const char *buffer;
190 size_t len;
191 void *resblock;
192 {
193 struct md5_ctx ctx;
194
195 /* Initialize the computation context. */
196 md5_init_ctx (&ctx);
197
198 /* Process whole buffer but last len % 64 bytes. */
199 md5_process_bytes (buffer, len, &ctx);
200
201 /* Put result in desired memory area. */
202 return md5_finish_ctx (&ctx, resblock);
203 }
204
205
206 void
207 md5_process_bytes (buffer, len, ctx)
208 const void *buffer;
209 size_t len;
210 struct md5_ctx *ctx;
211 {
212 #define NUM_MD5_WORDS 1024
213 size_t add = 0;
214
215 /* When we already have some bits in our internal buffer concatenate
216 both inputs first. */
217 if (ctx->buflen != 0)
218 {
219 size_t left_over = ctx->buflen;
220
221 add = 128 - left_over > len ? len : 128 - left_over;
222
223 memcpy (&ctx->buffer[left_over], buffer, add);
224 ctx->buflen += add;
225
226 if (left_over + add > 64)
227 {
228 md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
229 /* The regions in the following copy operation cannot overlap. */
230 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
231 (left_over + add) & 63);
232 ctx->buflen = (left_over + add) & 63;
233 }
234
235 buffer = (const char *) buffer + add;
236 len -= add;
237 }
238
239 /* Process available complete blocks. */
240 if (len > 64)
241 {
242 if ((add & 3) == 0) /* buffer is still 32-bit aligned */
243 {
244 md5_process_block (buffer, len & ~63, ctx);
245 buffer = (const char *) buffer + (len & ~63);
246 }
247 else /* buffer is not 32-bit aligned */
248 {
249 md5_uint32 md5_buffer[NUM_MD5_WORDS];
250 size_t num_bytes;
251 size_t buf_bytes;
252
253 num_bytes = len & ~63;
254 while (num_bytes > 0)
255 {
256 buf_bytes = (num_bytes < sizeof (md5_buffer)) ?
257 num_bytes : sizeof (md5_buffer);
258 memcpy (md5_buffer, buffer, buf_bytes);
259 md5_process_block (md5_buffer, buf_bytes, ctx);
260 num_bytes -= buf_bytes;
261 buffer = (const char *) buffer + buf_bytes;
262 }
263 }
264
265 len &= 63;
266 }
267
268 /* Move remaining bytes in internal buffer. */
269 if (len > 0)
270 {
271 memcpy (ctx->buffer, buffer, len);
272 ctx->buflen = len;
273 }
274 }
275
276
277 /* These are the four functions used in the four steps of the MD5 algorithm
278 and defined in the RFC 1321. The first function is a little bit optimized
279 (as found in Colin Plumbs public domain implementation). */
280 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
281 #define FF(b, c, d) (d ^ (b & (c ^ d)))
282 #define FG(b, c, d) FF (d, b, c)
283 #define FH(b, c, d) (b ^ c ^ d)
284 #define FI(b, c, d) (c ^ (b | ~d))
285
286 /* Process LEN bytes of BUFFER, accumulating context into CTX.
287 It is assumed that LEN % 64 == 0. */
288
289 void
290 md5_process_block (buffer, len, ctx)
291 const void *buffer;
292 size_t len;
293 struct md5_ctx *ctx;
294 {
295 md5_uint32 correct_words[16];
296 const md5_uint32 *words = buffer;
297 size_t nwords = len / sizeof (md5_uint32);
298 const md5_uint32 *endp = words + nwords;
299 md5_uint32 A = ctx->A;
300 md5_uint32 B = ctx->B;
301 md5_uint32 C = ctx->C;
302 md5_uint32 D = ctx->D;
303
304 /* First increment the byte count. RFC 1321 specifies the possible
305 length of the file up to 2^64 bits. Here we only compute the
306 number of bytes. Do a double word increment. */
307 ctx->total[0] += len;
308 if (ctx->total[0] < len)
309 ++ctx->total[1];
310
311 /* Process all bytes in the buffer with 64 bytes in each round of
312 the loop. */
313 while (words < endp)
314 {
315 md5_uint32 *cwp = correct_words;
316 md5_uint32 A_save = A;
317 md5_uint32 B_save = B;
318 md5_uint32 C_save = C;
319 md5_uint32 D_save = D;
320
321 /* First round: using the given function, the context and a constant
322 the next context is computed. Because the algorithms processing
323 unit is a 32-bit word and it is determined to work on words in
324 little endian byte order we perhaps have to change the byte order
325 before the computation. To reduce the work for the next steps
326 we store the swapped words in the array CORRECT_WORDS. */
327
328 #define OP(a, b, c, d, s, T) \
329 do \
330 { \
331 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
332 ++words; \
333 CYCLIC (a, s); \
334 a += b; \
335 } \
336 while (0)
337
338 /* It is unfortunate that C does not provide an operator for
339 cyclic rotation. Hope the C compiler is smart enough. */
340 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
341
342 /* Before we start, one word to the strange constants.
343 They are defined in RFC 1321 as
344
345 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
346 */
347
348 /* Round 1. */
349 OP (A, B, C, D, 7, 0xd76aa478);
350 OP (D, A, B, C, 12, 0xe8c7b756);
351 OP (C, D, A, B, 17, 0x242070db);
352 OP (B, C, D, A, 22, 0xc1bdceee);
353 OP (A, B, C, D, 7, 0xf57c0faf);
354 OP (D, A, B, C, 12, 0x4787c62a);
355 OP (C, D, A, B, 17, 0xa8304613);
356 OP (B, C, D, A, 22, 0xfd469501);
357 OP (A, B, C, D, 7, 0x698098d8);
358 OP (D, A, B, C, 12, 0x8b44f7af);
359 OP (C, D, A, B, 17, 0xffff5bb1);
360 OP (B, C, D, A, 22, 0x895cd7be);
361 OP (A, B, C, D, 7, 0x6b901122);
362 OP (D, A, B, C, 12, 0xfd987193);
363 OP (C, D, A, B, 17, 0xa679438e);
364 OP (B, C, D, A, 22, 0x49b40821);
365
366 /* For the second to fourth round we have the possibly swapped words
367 in CORRECT_WORDS. Redefine the macro to take an additional first
368 argument specifying the function to use. */
369 #undef OP
370 #define OP(f, a, b, c, d, k, s, T) \
371 do \
372 { \
373 a += f (b, c, d) + correct_words[k] + T; \
374 CYCLIC (a, s); \
375 a += b; \
376 } \
377 while (0)
378
379 /* Round 2. */
380 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
381 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
382 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
383 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
384 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
385 OP (FG, D, A, B, C, 10, 9, 0x02441453);
386 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
387 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
388 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
389 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
390 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
391 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
392 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
393 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
394 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
395 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
396
397 /* Round 3. */
398 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
399 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
400 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
401 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
402 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
403 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
404 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
405 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
406 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
407 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
408 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
409 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
410 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
411 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
412 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
413 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
414
415 /* Round 4. */
416 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
417 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
418 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
419 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
420 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
421 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
422 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
423 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
424 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
425 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
426 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
427 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
428 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
429 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
430 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
431 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
432
433 /* Add the starting values of the context. */
434 A += A_save;
435 B += B_save;
436 C += C_save;
437 D += D_save;
438 }
439
440 /* Put checksum in context given as argument. */
441 ctx->A = A;
442 ctx->B = B;
443 ctx->C = C;
444 ctx->D = D;
445 }
md5_ctx
Definition: md5.h:80