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Revision 61 - (show annotations)
Mon Aug 27 22:38:35 2007 UTC (14 years, 5 months ago) by gray
File MIME type: text/plain
File size: 13602 byte(s)
Lots of fixes in pam_mysql
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) 1995,1996,1997,1999,2000,2001,2005,2006
4 Free Software 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 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 "md5.h"
28
29 #include <stddef.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <sys/types.h>
33
34 #if USE_UNLOCKED_IO
35 # include "unlocked-io.h"
36 #endif
37
38 #ifdef _LIBC
39 # include <endian.h>
40 # if __BYTE_ORDER == __BIG_ENDIAN
41 # define WORDS_BIGENDIAN 1
42 # endif
43
44 #endif
45
46 #ifdef WORDS_BIGENDIAN
47 # define SWAP(n) \
48 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
49 #else
50 # define SWAP(n) (n)
51 #endif
52
53 #define BLOCKSIZE 4096
54 #if BLOCKSIZE % 64 != 0
55 # error "invalid BLOCKSIZE"
56 #endif
57
58 /* This array contains the bytes used to pad the buffer to the next
59 64-byte boundary. (RFC 1321, 3.1: Step 1) */
60 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
61
62
63 /* Initialize structure containing state of computation.
64 (RFC 1321, 3.3: Step 3) */
65 void
66 md5_init_ctx (struct md5_ctx *ctx)
67 {
68 ctx->A = 0x67452301;
69 ctx->B = 0xefcdab89;
70 ctx->C = 0x98badcfe;
71 ctx->D = 0x10325476;
72
73 ctx->total[0] = ctx->total[1] = 0;
74 ctx->buflen = 0;
75 }
76
77 /* Put result from CTX in first 16 bytes following RESBUF. The result
78 must be in little endian byte order.
79
80 IMPORTANT: On some systems it is required that RESBUF is correctly
81 aligned for a 32-bit value. */
82 void *
83 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
84 {
85 ((uint32_t *) resbuf)[0] = SWAP (ctx->A);
86 ((uint32_t *) resbuf)[1] = SWAP (ctx->B);
87 ((uint32_t *) resbuf)[2] = SWAP (ctx->C);
88 ((uint32_t *) resbuf)[3] = SWAP (ctx->D);
89
90 return resbuf;
91 }
92
93 /* Process the remaining bytes in the internal buffer and the usual
94 prolog according to the standard and write the result to RESBUF.
95
96 IMPORTANT: On some systems it is required that RESBUF is correctly
97 aligned for a 32-bit value. */
98 void *
99 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
100 {
101 /* Take yet unprocessed bytes into account. */
102 uint32_t bytes = ctx->buflen;
103 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
104
105 /* Now count remaining bytes. */
106 ctx->total[0] += bytes;
107 if (ctx->total[0] < bytes)
108 ++ctx->total[1];
109
110 /* Put the 64-bit file length in *bits* at the end of the buffer. */
111 ctx->buffer[size - 2] = SWAP (ctx->total[0] << 3);
112 ctx->buffer[size - 1] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
113
114 memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
115
116 /* Process last bytes. */
117 md5_process_block (ctx->buffer, size * 4, ctx);
118
119 return md5_read_ctx (ctx, resbuf);
120 }
121
122 /* Compute MD5 message digest for bytes read from STREAM. The
123 resulting message digest number will be written into the 16 bytes
124 beginning at RESBLOCK. */
125 int
126 md5_stream (FILE *stream, void *resblock)
127 {
128 struct md5_ctx ctx;
129 char buffer[BLOCKSIZE + 72];
130 size_t sum;
131
132 /* Initialize the computation context. */
133 md5_init_ctx (&ctx);
134
135 /* Iterate over full file contents. */
136 while (1)
137 {
138 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
139 computation function processes the whole buffer so that with the
140 next round of the loop another block can be read. */
141 size_t n;
142 sum = 0;
143
144 /* Read block. Take care for partial reads. */
145 while (1)
146 {
147 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
148
149 sum += n;
150
151 if (sum == BLOCKSIZE)
152 break;
153
154 if (n == 0)
155 {
156 /* Check for the error flag IFF N == 0, so that we don't
157 exit the loop after a partial read due to e.g., EAGAIN
158 or EWOULDBLOCK. */
159 if (ferror (stream))
160 return 1;
161 goto process_partial_block;
162 }
163
164 /* We've read at least one byte, so ignore errors. But always
165 check for EOF, since feof may be true even though N > 0.
166 Otherwise, we could end up calling fread after EOF. */
167 if (feof (stream))
168 goto process_partial_block;
169 }
170
171 /* Process buffer with BLOCKSIZE bytes. Note that
172 BLOCKSIZE % 64 == 0
173 */
174 md5_process_block (buffer, BLOCKSIZE, &ctx);
175 }
176
177 process_partial_block:
178
179 /* Process any remaining bytes. */
180 if (sum > 0)
181 md5_process_bytes (buffer, sum, &ctx);
182
183 /* Construct result in desired memory. */
184 md5_finish_ctx (&ctx, resblock);
185 return 0;
186 }
187
188 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
189 result is always in little endian byte order, so that a byte-wise
190 output yields to the wanted ASCII representation of the message
191 digest. */
192 void *
193 md5_buffer (const char *buffer, size_t len, void *resblock)
194 {
195 struct md5_ctx ctx;
196
197 /* Initialize the computation context. */
198 md5_init_ctx (&ctx);
199
200 /* Process whole buffer but last len % 64 bytes. */
201 md5_process_bytes (buffer, len, &ctx);
202
203 /* Put result in desired memory area. */
204 return md5_finish_ctx (&ctx, resblock);
205 }
206
207
208 void
209 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
210 {
211 /* When we already have some bits in our internal buffer concatenate
212 both inputs first. */
213 if (ctx->buflen != 0)
214 {
215 size_t left_over = ctx->buflen;
216 size_t add = 128 - left_over > len ? len : 128 - left_over;
217
218 memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
219 ctx->buflen += add;
220
221 if (ctx->buflen > 64)
222 {
223 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
224
225 ctx->buflen &= 63;
226 /* The regions in the following copy operation cannot overlap. */
227 memcpy (ctx->buffer,
228 &((char *) ctx->buffer)[(left_over + add) & ~63],
229 ctx->buflen);
230 }
231
232 buffer = (const char *) buffer + add;
233 len -= add;
234 }
235
236 /* Process available complete blocks. */
237 if (len >= 64)
238 {
239 #if !_STRING_ARCH_unaligned
240 # define alignof(type) offsetof (struct { char c; type x; }, x)
241 # define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0)
242 if (UNALIGNED_P (buffer))
243 while (len > 64)
244 {
245 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
246 buffer = (const char *) buffer + 64;
247 len -= 64;
248 }
249 else
250 #endif
251 {
252 md5_process_block (buffer, len & ~63, ctx);
253 buffer = (const char *) buffer + (len & ~63);
254 len &= 63;
255 }
256 }
257
258 /* Move remaining bytes in internal buffer. */
259 if (len > 0)
260 {
261 size_t left_over = ctx->buflen;
262
263 memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
264 left_over += len;
265 if (left_over >= 64)
266 {
267 md5_process_block (ctx->buffer, 64, ctx);
268 left_over -= 64;
269 memcpy (ctx->buffer, &ctx->buffer[16], left_over);
270 }
271 ctx->buflen = left_over;
272 }
273 }
274
275
276 /* These are the four functions used in the four steps of the MD5 algorithm
277 and defined in the RFC 1321. The first function is a little bit optimized
278 (as found in Colin Plumbs public domain implementation). */
279 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
280 #define FF(b, c, d) (d ^ (b & (c ^ d)))
281 #define FG(b, c, d) FF (d, b, c)
282 #define FH(b, c, d) (b ^ c ^ d)
283 #define FI(b, c, d) (c ^ (b | ~d))
284
285 /* Process LEN bytes of BUFFER, accumulating context into CTX.
286 It is assumed that LEN % 64 == 0. */
287
288 void
289 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
290 {
291 uint32_t correct_words[16];
292 const uint32_t *words = buffer;
293 size_t nwords = len / sizeof (uint32_t);
294 const uint32_t *endp = words + nwords;
295 uint32_t A = ctx->A;
296 uint32_t B = ctx->B;
297 uint32_t C = ctx->C;
298 uint32_t D = ctx->D;
299
300 /* First increment the byte count. RFC 1321 specifies the possible
301 length of the file up to 2^64 bits. Here we only compute the
302 number of bytes. Do a double word increment. */
303 ctx->total[0] += len;
304 if (ctx->total[0] < len)
305 ++ctx->total[1];
306
307 /* Process all bytes in the buffer with 64 bytes in each round of
308 the loop. */
309 while (words < endp)
310 {
311 uint32_t *cwp = correct_words;
312 uint32_t A_save = A;
313 uint32_t B_save = B;
314 uint32_t C_save = C;
315 uint32_t D_save = D;
316
317 /* First round: using the given function, the context and a constant
318 the next context is computed. Because the algorithms processing
319 unit is a 32-bit word and it is determined to work on words in
320 little endian byte order we perhaps have to change the byte order
321 before the computation. To reduce the work for the next steps
322 we store the swapped words in the array CORRECT_WORDS. */
323
324 #define OP(a, b, c, d, s, T) \
325 do \
326 { \
327 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
328 ++words; \
329 CYCLIC (a, s); \
330 a += b; \
331 } \
332 while (0)
333
334 /* It is unfortunate that C does not provide an operator for
335 cyclic rotation. Hope the C compiler is smart enough. */
336 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
337
338 /* Before we start, one word to the strange constants.
339 They are defined in RFC 1321 as
340
341 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
342
343 Here is an equivalent invocation using Perl:
344
345 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
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 }

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