Mercurial > hg > xemacs-beta

comparison src/md5.c @ 428:3ecd8885ac67 r21-2-22

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Import from CVS: tag r21-2-22
author cvs
date Mon, 13 Aug 2007 11:28:15 +0200
parents
children 84b14dcb0985
comparison
equal deleted inserted replaced
427:0a0253eac470 428:3ecd8885ac67
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20
21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
22
23 /* XEmacs frontend written by Ben Wing, Jareth Hein and Hrvoje Niksic. */
24
25 #ifdef HAVE_CONFIG_H
26 # include <config.h>
27 #endif
28
29 #include <sys/types.h>
30 #include <string.h>
31 #include <stdio.h>
32
33 #if defined HAVE_LIMITS_H || _LIBC
34 # include <limits.h>
35 #endif
36
37 /* The following contortions are an attempt to use the C preprocessor
38 to determine an unsigned integral type that is 32 bits wide. An
39 alternative approach is to use autoconf's AC_CHECK_SIZEOF macro, but
40 doing that would require that the configure script compile and *run*
41 the resulting executable. Locally running cross-compiled executables
42 is usually not possible. */
43
44 #ifdef _LIBC
45 # include <sys/types.h>
46 typedef u_int32_t md5_uint32;
47 #else
48 # if defined __STDC__ && __STDC__
49 # define UINT_MAX_32_BITS 4294967295U
50 # else
51 # define UINT_MAX_32_BITS 0xFFFFFFFF
52 # endif
53
54 /* If UINT_MAX isn't defined, assume it's a 32-bit type.
55 This should be valid for all systems GNU cares about because
56 that doesn't include 16-bit systems, and only modern systems
57 (that certainly have <limits.h>) have 64+-bit integral types. */
58
59 # ifndef UINT_MAX
60 # define UINT_MAX UINT_MAX_32_BITS
61 # endif
62
63 # if UINT_MAX == UINT_MAX_32_BITS
64 typedef unsigned int md5_uint32;
65 # else
66 # if USHRT_MAX == UINT_MAX_32_BITS
67 typedef unsigned short md5_uint32;
68 # else
69 # if ULONG_MAX == UINT_MAX_32_BITS
70 typedef unsigned long md5_uint32;
71 # else
72 /* The following line is intended to evoke an error.
73 Using #error is not portable enough. */
74 "Cannot determine unsigned 32-bit data type."
75 # endif
76 # endif
77 # endif
78 #endif
79
80 #include "lisp.h"
81 #include "buffer.h"
82 #include "lstream.h"
83 #ifdef FILE_CODING
84 # include "file-coding.h"
85 #endif
86
87 /* Structure to save state of computation between the single steps. */
88 struct md5_ctx
89 {
90 md5_uint32 A;
91 md5_uint32 B;
92 md5_uint32 C;
93 md5_uint32 D;
94
95 md5_uint32 total[2];
96 md5_uint32 buflen;
97 char buffer[128];
98 };
99
100 #ifdef WORDS_BIGENDIAN
101 # define SWAP(n) \
102 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
103 #else
104 # define SWAP(n) (n)
105 #endif
106
107
108 /* This array contains the bytes used to pad the buffer to the next
109 64-byte boundary. (RFC 1321, 3.1: Step 1) */
110 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
111
112
113 static void md5_process_block (CONST void *, size_t, struct md5_ctx *);
114
115
116 /* Initialize structure containing state of computation.
117 (RFC 1321, 3.3: Step 3) */
118 static void
119 md5_init_ctx (struct md5_ctx *ctx)
120 {
121 ctx->A = 0x67452301;
122 ctx->B = 0xefcdab89;
123 ctx->C = 0x98badcfe;
124 ctx->D = 0x10325476;
125
126 ctx->total[0] = ctx->total[1] = 0;
127 ctx->buflen = 0;
128 }
129
130 /* Put result from CTX in first 16 bytes following RESBUF. The result
131 must be in little endian byte order.
132
133 IMPORTANT: On some systems it is required that RESBUF is correctly
134 aligned for a 32 bits value. */
135 static void *
136 md5_read_ctx (CONST struct md5_ctx *ctx, void *resbuf)
137 {
138 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
139 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
140 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
141 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
142
143 return resbuf;
144 }
145
146 /* Process the remaining bytes in the internal buffer and the usual
147 prolog according to the standard and write the result to RESBUF.
148
149 IMPORTANT: On some systems it is required that RESBUF is correctly
150 aligned for a 32 bits value. */
151 static void *
152 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
153 {
154 /* Take yet unprocessed bytes into account. */
155 md5_uint32 bytes = ctx->buflen;
156 size_t pad;
157
158 /* Now count remaining bytes. */
159 ctx->total[0] += bytes;
160 if (ctx->total[0] < bytes)
161 ++ctx->total[1];
162
163 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
164 memcpy (&ctx->buffer[bytes], fillbuf, pad);
165
166 /* Put the 64-bit file length in *bits* at the end of the buffer. */
167 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
168 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
169 (ctx->total[0] >> 29));
170
171 /* Process last bytes. */
172 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
173
174 return md5_read_ctx (ctx, resbuf);
175 }
176
177 #ifndef emacs /* unused in Emacs */
178 /* Compute MD5 message digest for bytes read from STREAM. The
179 resulting message digest number will be written into the 16 bytes
180 beginning at RESBLOCK. */
181 int
182 md5_stream (FILE *stream, void *resblock)
183 {
184 /* Important: BLOCKSIZE must be a multiple of 64. */
185 #define BLOCKSIZE 4096
186 struct md5_ctx ctx;
187 char buffer[BLOCKSIZE + 72];
188 size_t sum;
189
190 /* Initialize the computation context. */
191 md5_init_ctx (&ctx);
192
193 /* Iterate over full file contents. */
194 while (1)
195 {
196 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
197 computation function processes the whole buffer so that with the
198 next round of the loop another block can be read. */
199 size_t n;
200 sum = 0;
201
202 /* Read block. Take care for partial reads. */
203 do
204 {
205 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
206
207 sum += n;
208 }
209 while (sum < BLOCKSIZE && n != 0);
210 if (n == 0 && ferror (stream))
211 return 1;
212
213 /* If end of file is reached, end the loop. */
214 if (n == 0)
215 break;
216
217 /* Process buffer with BLOCKSIZE bytes. Note that
218 BLOCKSIZE % 64 == 0
219 */
220 md5_process_block (buffer, BLOCKSIZE, &ctx);
221 }
222
223 /* Add the last bytes if necessary. */
224 if (sum > 0)
225 md5_process_bytes (buffer, sum, &ctx);
226
227 /* Construct result in desired memory. */
228 md5_finish_ctx (&ctx, resblock);
229 return 0;
230 }
231
232 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
233 result is always in little endian byte order, so that a byte-wise
234 output yields to the wanted ASCII representation of the message
235 digest. */
236 void *
237 md5_buffer (const char *buffer, size_t len, void *resblock)
238 {
239 struct md5_ctx ctx;
240
241 /* Initialize the computation context. */
242 md5_init_ctx (&ctx);
243
244 /* Process whole buffer but last len % 64 bytes. */
245 md5_process_bytes (buffer, len, &ctx);
246
247 /* Put result in desired memory area. */
248 return md5_finish_ctx (&ctx, resblock);
249 }
250 #endif /* not emacs */
251
252
253 static void
254 md5_process_bytes (CONST void *buffer, size_t len, struct md5_ctx *ctx)
255 {
256 /* When we already have some bits in our internal buffer concatenate
257 both inputs first. */
258 if (ctx->buflen != 0)
259 {
260 size_t left_over = ctx->buflen;
261 size_t add = 128 - left_over > len ? len : 128 - left_over;
262
263 memcpy (&ctx->buffer[left_over], buffer, add);
264 ctx->buflen += add;
265
266 if (left_over + add > 64)
267 {
268 md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
269 /* The regions in the following copy operation cannot overlap. */
270 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
271 (left_over + add) & 63);
272 ctx->buflen = (left_over + add) & 63;
273 }
274
275 buffer = (const char *) buffer + add;
276 len -= add;
277 }
278
279 /* Process available complete blocks. */
280 if (len > 64)
281 {
282 md5_process_block (buffer, len & ~63, ctx);
283 buffer = (const char *) buffer + (len & ~63);
284 len &= 63;
285 }
286
287 /* Move remaining bytes in internal buffer. */
288 if (len > 0)
289 {
290 memcpy (ctx->buffer, buffer, len);
291 ctx->buflen = len;
292 }
293 }
294
295
296 /* These are the four functions used in the four steps of the MD5 algorithm
297 and defined in the RFC 1321. The first function is a little bit optimized
298 (as found in Colin Plumbs public domain implementation). */
299 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
300 #define FF(b, c, d) (d ^ (b & (c ^ d)))
301 #define FG(b, c, d) FF (d, b, c)
302 #define FH(b, c, d) (b ^ c ^ d)
303 #define FI(b, c, d) (c ^ (b | ~d))
304
305 /* Process LEN bytes of BUFFER, accumulating context into CTX.
306 It is assumed that LEN % 64 == 0. */
307
308 static void
309 md5_process_block (CONST void *buffer, size_t len, struct md5_ctx *ctx)
310 {
311 md5_uint32 correct_words[16];
312 const md5_uint32 *words = (const md5_uint32 *) buffer;
313 size_t nwords = len / sizeof (md5_uint32);
314 const md5_uint32 *endp = words + nwords;
315 md5_uint32 A = ctx->A;
316 md5_uint32 B = ctx->B;
317 md5_uint32 C = ctx->C;
318 md5_uint32 D = ctx->D;
319
320 /* First increment the byte count. RFC 1321 specifies the possible
321 length of the file up to 2^64 bits. Here we only compute the
322 number of bytes. Do a double word increment. */
323 ctx->total[0] += len;
324 if (ctx->total[0] < len)
325 ++ctx->total[1];
326
327 /* Process all bytes in the buffer with 64 bytes in each round of
328 the loop. */
329 while (words < endp)
330 {
331 md5_uint32 *cwp = correct_words;
332 md5_uint32 A_save = A;
333 md5_uint32 B_save = B;
334 md5_uint32 C_save = C;
335 md5_uint32 D_save = D;
336
337 /* First round: using the given function, the context and a constant
338 the next context is computed. Because the algorithms processing
339 unit is a 32-bit word and it is determined to work on words in
340 little endian byte order we perhaps have to change the byte order
341 before the computation. To reduce the work for the next steps
342 we store the swapped words in the array CORRECT_WORDS. */
343
344 #define OP(a, b, c, d, s, T) \
345 do \
346 { \
347 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
348 ++words; \
349 CYCLIC (a, s); \
350 a += b; \
351 } \
352 while (0)
353
354 /* It is unfortunate that C does not provide an operator for
355 cyclic rotation. Hope the C compiler is smart enough. */
356 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
357
358 /* Before we start, one word to the strange constants.
359 They are defined in RFC 1321 as
360
361 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
362 */
363
364 /* Round 1. */
365 OP (A, B, C, D, 7, 0xd76aa478);
366 OP (D, A, B, C, 12, 0xe8c7b756);
367 OP (C, D, A, B, 17, 0x242070db);
368 OP (B, C, D, A, 22, 0xc1bdceee);
369 OP (A, B, C, D, 7, 0xf57c0faf);
370 OP (D, A, B, C, 12, 0x4787c62a);
371 OP (C, D, A, B, 17, 0xa8304613);
372 OP (B, C, D, A, 22, 0xfd469501);
373 OP (A, B, C, D, 7, 0x698098d8);
374 OP (D, A, B, C, 12, 0x8b44f7af);
375 OP (C, D, A, B, 17, 0xffff5bb1);
376 OP (B, C, D, A, 22, 0x895cd7be);
377 OP (A, B, C, D, 7, 0x6b901122);
378 OP (D, A, B, C, 12, 0xfd987193);
379 OP (C, D, A, B, 17, 0xa679438e);
380 OP (B, C, D, A, 22, 0x49b40821);
381
382 /* For the second to fourth round we have the possibly swapped words
383 in CORRECT_WORDS. Redefine the macro to take an additional first
384 argument specifying the function to use. */
385 #undef OP
386 #define OP(f, a, b, c, d, k, s, T) \
387 do \
388 { \
389 a += f (b, c, d) + correct_words[k] + T; \
390 CYCLIC (a, s); \
391 a += b; \
392 } \
393 while (0)
394
395 /* Round 2. */
396 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
397 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
398 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
399 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
400 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
401 OP (FG, D, A, B, C, 10, 9, 0x02441453);
402 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
403 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
404 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
405 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
406 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
407 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
408 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
409 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
410 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
411 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
412
413 /* Round 3. */
414 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
415 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
416 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
417 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
418 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
419 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
420 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
421 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
422 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
423 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
424 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
425 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
426 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
427 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
428 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
429 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
430
431 /* Round 4. */
432 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
433 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
434 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
435 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
436 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
437 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
438 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
439 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
440 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
441 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
442 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
443 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
444 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
445 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
446 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
447 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
448
449 /* Add the starting values of the context. */
450 A += A_save;
451 B += B_save;
452 C += C_save;
453 D += D_save;
454 }
455
456 /* Put checksum in context given as argument. */
457 ctx->A = A;
458 ctx->B = B;
459 ctx->C = C;
460 ctx->D = D;
461 }
462
463
464 #ifdef emacs
465 #ifdef FILE_CODING
466 /* Find out what format the buffer will be saved in, so we can make
467 the digest based on what it will look like on disk. */
468 static Lisp_Object
469 md5_coding_system (Lisp_Object object, Lisp_Object coding, Lisp_Object istream,
470 int error_me_not)
471 {
472 Lisp_Object coding_system;
473
474 if (NILP (coding))
475 {
476 if (BUFFERP (object))
477 {
478 /* Use the file coding for this buffer by default. */
479 coding_system = XBUFFER (object)->buffer_file_coding_system;
480 }
481 else
482 {
483 /* Attempt to autodetect the coding of the string. This is
484 VERY hit-and-miss. */
485 enum eol_type eol = EOL_AUTODETECT;
486 coding_system = Fget_coding_system (Qundecided);
487 determine_real_coding_system (XLSTREAM (istream),
488 &coding_system, &eol);
489 }
490 if (NILP (coding_system))
491 coding_system = Fget_coding_system (Qbinary);
492 else
493 {
494 coding_system = Ffind_coding_system (coding_system);
495 if (NILP (coding_system))
496 coding_system = Fget_coding_system (Qbinary);
497 }
498 }
499 else
500 {
501 coding_system = Ffind_coding_system (coding);
502 if (NILP (coding_system))
503 {
504 if (error_me_not)
505 /* Default to binary. */
506 coding_system = Fget_coding_system (Qbinary);
507 else
508 signal_simple_error ("No such coding system", coding);
509 }
510 }
511 return coding_system;
512 }
513 #endif /* FILE_CODING */
514
515
516 DEFUN ("md5", Fmd5, 1, 5, 0, /*
517 Return the MD5 message digest of OBJECT, a buffer or string.
518
519 Optional arguments START and END denote positions for computing the
520 digest of a portion of OBJECT.
521
522 The optional CODING argument specifies the coding system the text is to be
523 represented in while computing the digest. If unspecified, it defaults
524 to the current format of the data, or is guessed.
525
526 If NOERROR is non-nil, silently assume binary coding if the guesswork
527 fails. Normally, an error is signaled in such case.
528
529 CODING and NOERROR arguments are meaningful only in XEmacsen with
530 file-coding or Mule support. Otherwise, they are ignored.
531 */
532 (object, start, end, coding, noerror))
533 {
534 /* This function can GC */
535 /* Can this really GC? How? */
536 struct md5_ctx ctx;
537 unsigned char digest[16];
538 unsigned char thehash[33];
539 int i;
540
541 Lisp_Object instream;
542 struct gcpro gcpro1;
543 #ifdef FILE_CODING
544 Lisp_Object raw_instream;
545 struct gcpro ngcpro1;
546 #endif
547
548 /* Set up the input stream. */
549 if (BUFFERP (object))
550 {
551 struct buffer *b;
552 Bufpos begv, endv;
553 CHECK_LIVE_BUFFER (object);
554 b = XBUFFER (object);
555 /* Figure out where we need to get info from */
556 get_buffer_range_char (b, start, end, &begv, &endv, GB_ALLOW_NIL);
557
558 instream = make_lisp_buffer_input_stream (b, begv, endv, 0);
559 }
560 else
561 {
562 Bytecount bstart, bend;
563 CHECK_STRING (object);
564 get_string_range_byte (object, start, end, &bstart, &bend,
565 GB_HISTORICAL_STRING_BEHAVIOR);
566 instream = make_lisp_string_input_stream (object, bstart, bend - bstart);
567 }
568 GCPRO1 (instream);
569
570 #ifdef FILE_CODING
571 /* Determine the coding and set up the conversion stream. */
572 coding = md5_coding_system (object, coding, instream, !NILP (noerror));
573 raw_instream = instream;
574 instream = make_encoding_input_stream (XLSTREAM (instream), coding);
575 NGCPRO1 (raw_instream);
576 #endif
577
578 /* Initialize MD5 context. */
579 md5_init_ctx (&ctx);
580
581 /* Get the data while doing the conversion. */
582 while (1)
583 {
584 Bufbyte tempbuf[1024]; /* some random amount */
585 ssize_t size_in_bytes =
586 Lstream_read (XLSTREAM (instream), tempbuf, sizeof (tempbuf));
587 if (!size_in_bytes)
588 break;
589
590 /* Process the bytes. */
591 md5_process_bytes (tempbuf, size_in_bytes, &ctx);
592 }
593 Lstream_delete (XLSTREAM (instream));
594 #ifdef FILE_CODING
595 Lstream_delete (XLSTREAM (raw_instream));
596 NUNGCPRO;
597 #endif
598 UNGCPRO;
599
600 md5_finish_ctx (&ctx, digest);
601 for (i = 0; i < 16; i++)
602 sprintf ((char *) (thehash + (i * 2)), "%02x", digest[i]);
603
604 return make_string (thehash, 32);
605 }
606
607 void
608 syms_of_md5 (void)
609 {
610 DEFSUBR (Fmd5);
611 }
612
613 void
614 vars_of_md5 (void)
615 {
616 Fprovide (intern ("md5"));
617 }
618 #endif /* emacs */