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