source: trunk/essentials/net-misc/wget/src/gnu-md5.c@ 3609

Last change on this file since 3609 was 3440, checked in by bird, 19 years ago

wget 1.10.2
File size: 12.5 KB
Line 
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 This file is part of the GNU C library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Library General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Library General Public License for more details.
15
16 You should have received a copy of the GNU Library General Public
17 License along with the GNU C Library; see the file COPYING.LIB. If not,
18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
20
21/* Written by Ulrich Drepper <[email protected]>, 1995. */
22
23#ifdef HAVE_CONFIG_H
24# include <config.h>
25#endif
26
27/* Wget */
28/*#if STDC_HEADERS || defined _LIBC*/
29# include <stdlib.h>
30#ifdef HAVE_STRING_H
31# include <string.h>
32#else
33# include <strings.h>
34#endif
35/*#else*/
36/*# ifndef HAVE_MEMCPY*/
37/*# define memcpy(d, s, n) bcopy ((s), (d), (n))*/
38/*# endif*/
39/*#endif*/
40
41#include "wget.h"
42#include "gnu-md5.h"
43
44#ifdef _LIBC
45# include <endian.h>
46# if __BYTE_ORDER == __BIG_ENDIAN
47# define WORDS_BIGENDIAN 1
48# endif
49#endif
50
51#ifdef WORDS_BIGENDIAN
52# define SWAP(n) \
53 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
54#else
55# define SWAP(n) (n)
56#endif
57
58
59/* This array contains the bytes used to pad the buffer to the next
60 64-byte boundary. (RFC 1321, 3.1: Step 1) */
61static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
62
63
64/* Initialize structure containing state of computation.
65 (RFC 1321, 3.3: Step 3) */
66void
67md5_init_ctx (struct md5_ctx *ctx)
68{
69 ctx->A = 0x67452301;
70 ctx->B = 0xefcdab89;
71 ctx->C = 0x98badcfe;
72 ctx->D = 0x10325476;
73
74 ctx->total[0] = ctx->total[1] = 0;
75 ctx->buflen = 0;
76}
77
78/* Put result from CTX in first 16 bytes following RESBUF. The result
79 must be in little endian byte order.
80
81 IMPORTANT: On some systems it is required that RESBUF is correctly
82 aligned for a 32 bits value. */
83void *
84md5_read_ctx (const struct md5_ctx *ctx, 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. */
99void *
100md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
101{
102 /* Take yet unprocessed bytes into account. */
103 md5_uint32 bytes = ctx->buflen;
104 size_t pad;
105
106 /* Now count remaining bytes. */
107 ctx->total[0] += bytes;
108 if (ctx->total[0] < bytes)
109 ++ctx->total[1];
110
111 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
112 memcpy (&ctx->buffer[bytes], fillbuf, pad);
113
114 /* Put the 64-bit file length in *bits* at the end of the buffer. */
115 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
116 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
117 (ctx->total[0] >> 29));
118
119 /* Process last bytes. */
120 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
121
122 return md5_read_ctx (ctx, resbuf);
123}
124
125/* Unused in Wget */
126#if 0
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. */
130int
131md5_stream (FILE *stream, void *resblock)
132{
133 /* Important: BLOCKSIZE must be a multiple of 64. */
134#define BLOCKSIZE 4096
135 struct md5_ctx ctx;
136 char buffer[BLOCKSIZE + 72];
137 size_t sum;
138
139 /* Initialize the computation context. */
140 md5_init_ctx (&ctx);
141
142 /* Iterate over full file contents. */
143 while (1)
144 {
145 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
146 computation function processes the whole buffer so that with the
147 next round of the loop another block can be read. */
148 size_t n;
149 sum = 0;
150
151 /* Read block. Take care for partial reads. */
152 do
153 {
154 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
155
156 sum += n;
157 }
158 while (sum < BLOCKSIZE && n != 0);
159 if (n == 0 && ferror (stream))
160 return 1;
161
162 /* If end of file is reached, end the loop. */
163 if (n == 0)
164 break;
165
166 /* Process buffer with BLOCKSIZE bytes. Note that
167 BLOCKSIZE % 64 == 0
168 */
169 md5_process_block (buffer, BLOCKSIZE, &ctx);
170 }
171
172 /* Add the last bytes if necessary. */
173 if (sum > 0)
174 md5_process_bytes (buffer, sum, &ctx);
175
176 /* Construct result in desired memory. */
177 md5_finish_ctx (&ctx, resblock);
178 return 0;
179}
180
181/* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
182 result is always in little endian byte order, so that a byte-wise
183 output yields to the wanted ASCII representation of the message
184 digest. */
185void *
186md5_buffer (const char *buffer, size_t len, void *resblock)
187{
188 struct md5_ctx ctx;
189
190 /* Initialize the computation context. */
191 md5_init_ctx (&ctx);
192
193 /* Process whole buffer but last len % 64 bytes. */
194 md5_process_bytes (buffer, len, &ctx);
195
196 /* Put result in desired memory area. */
197 return md5_finish_ctx (&ctx, resblock);
198}
199#endif /* 0 */
200
201
202void
203md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
204{
205 /* When we already have some bits in our internal buffer concatenate
206 both inputs first. */
207 if (ctx->buflen != 0)
208 {
209 size_t left_over = ctx->buflen;
210 size_t add = 128 - left_over > len ? len : 128 - left_over;
211
212 memcpy (&ctx->buffer[left_over], buffer, add);
213 ctx->buflen += add;
214
215 if (left_over + add > 64)
216 {
217 md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
218 /* The regions in the following copy operation cannot overlap. */
219 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
220 (left_over + add) & 63);
221 ctx->buflen = (left_over + add) & 63;
222 }
223
224 buffer = (const char *) buffer + add;
225 len -= add;
226 }
227
228 /* Process available complete blocks. */
229 if (len > 64)
230 {
231 md5_process_block (buffer, len & ~63, ctx);
232 buffer = (const char *) buffer + (len & ~63);
233 len &= 63;
234 }
235
236 /* Move remaining bytes in internal buffer. */
237 if (len > 0)
238 {
239 memcpy (ctx->buffer, buffer, len);
240 ctx->buflen = len;
241 }
242}
243
244
245/* These are the four functions used in the four steps of the MD5 algorithm
246 and defined in the RFC 1321. The first function is a little bit optimized
247 (as found in Colin Plumbs public domain implementation). */
248/* #define FF(b, c, d) ((b & c) | (~b & d)) */
249#define FF(b, c, d) (d ^ (b & (c ^ d)))
250#define FG(b, c, d) FF (d, b, c)
251#define FH(b, c, d) (b ^ c ^ d)
252#define FI(b, c, d) (c ^ (b | ~d))
253
254/* Process LEN bytes of BUFFER, accumulating context into CTX.
255 It is assumed that LEN % 64 == 0. */
256
257void
258md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
259{
260 md5_uint32 correct_words[16];
261 const md5_uint32 *words = (md5_uint32 *)buffer;
262 size_t nwords = len / sizeof (md5_uint32);
263 const md5_uint32 *endp = words + nwords;
264 md5_uint32 A = ctx->A;
265 md5_uint32 B = ctx->B;
266 md5_uint32 C = ctx->C;
267 md5_uint32 D = ctx->D;
268
269 /* First increment the byte count. RFC 1321 specifies the possible
270 length of the file up to 2^64 bits. Here we only compute the
271 number of bytes. Do a double word increment. */
272 ctx->total[0] += len;
273 if (ctx->total[0] < len)
274 ++ctx->total[1];
275
276 /* Process all bytes in the buffer with 64 bytes in each round of
277 the loop. */
278 while (words < endp)
279 {
280 md5_uint32 *cwp = correct_words;
281 md5_uint32 A_save = A;
282 md5_uint32 B_save = B;
283 md5_uint32 C_save = C;
284 md5_uint32 D_save = D;
285
286 /* First round: using the given function, the context and a constant
287 the next context is computed. Because the algorithms processing
288 unit is a 32-bit word and it is determined to work on words in
289 little endian byte order we perhaps have to change the byte order
290 before the computation. To reduce the work for the next steps
291 we store the swapped words in the array CORRECT_WORDS. */
292
293#define OP(a, b, c, d, s, T) \
294 do \
295 { \
296 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
297 ++words; \
298 CYCLIC (a, s); \
299 a += b; \
300 } \
301 while (0)
302
303 /* It is unfortunate that C does not provide an operator for
304 cyclic rotation. Hope the C compiler is smart enough. */
305#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
306
307 /* Before we start, one word to the strange constants.
308 They are defined in RFC 1321 as
309
310 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
311 */
312
313 /* Round 1. */
314 OP (A, B, C, D, 7, 0xd76aa478);
315 OP (D, A, B, C, 12, 0xe8c7b756);
316 OP (C, D, A, B, 17, 0x242070db);
317 OP (B, C, D, A, 22, 0xc1bdceee);
318 OP (A, B, C, D, 7, 0xf57c0faf);
319 OP (D, A, B, C, 12, 0x4787c62a);
320 OP (C, D, A, B, 17, 0xa8304613);
321 OP (B, C, D, A, 22, 0xfd469501);
322 OP (A, B, C, D, 7, 0x698098d8);
323 OP (D, A, B, C, 12, 0x8b44f7af);
324 OP (C, D, A, B, 17, 0xffff5bb1);
325 OP (B, C, D, A, 22, 0x895cd7be);
326 OP (A, B, C, D, 7, 0x6b901122);
327 OP (D, A, B, C, 12, 0xfd987193);
328 OP (C, D, A, B, 17, 0xa679438e);
329 OP (B, C, D, A, 22, 0x49b40821);
330
331 /* For the second to fourth round we have the possibly swapped words
332 in CORRECT_WORDS. Redefine the macro to take an additional first
333 argument specifying the function to use. */
334#undef OP
335#define OP(f, a, b, c, d, k, s, T) \
336 do \
337 { \
338 a += f (b, c, d) + correct_words[k] + T; \
339 CYCLIC (a, s); \
340 a += b; \
341 } \
342 while (0)
343
344 /* Round 2. */
345 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
346 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
347 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
348 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
349 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
350 OP (FG, D, A, B, C, 10, 9, 0x02441453);
351 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
352 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
353 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
354 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
355 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
356 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
357 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
358 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
359 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
360 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
361
362 /* Round 3. */
363 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
364 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
365 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
366 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
367 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
368 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
369 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
370 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
371 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
372 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
373 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
374 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
375 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
376 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
377 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
378 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
379
380 /* Round 4. */
381 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
382 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
383 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
384 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
385 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
386 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
387 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
388 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
389 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
390 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
391 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
392 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
393 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
394 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
395 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
396 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
397
398 /* Add the starting values of the context. */
399 A += A_save;
400 B += B_save;
401 C += C_save;
402 D += D_save;
403 }
404
405 /* Put checksum in context given as argument. */
406 ctx->A = A;
407 ctx->B = B;
408 ctx->C = C;
409 ctx->D = D;
410}
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