Line data Source code
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) 1995-2011, 2015 Red Hat, Inc.
4 : This file is part of elfutils.
5 : Written by Ulrich Drepper <drepper@redhat.com>, 1995.
6 :
7 : This file is free software; you can redistribute it and/or modify
8 : it under the terms of either
9 :
10 : * the GNU Lesser General Public License as published by the Free
11 : Software Foundation; either version 3 of the License, or (at
12 : your option) any later version
13 :
14 : or
15 :
16 : * the GNU General Public License as published by the Free
17 : Software Foundation; either version 2 of the License, or (at
18 : your option) any later version
19 :
20 : or both in parallel, as here.
21 :
22 : elfutils is distributed in the hope that it will be useful, but
23 : WITHOUT ANY WARRANTY; without even the implied warranty of
24 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
25 : General Public License for more details.
26 :
27 : You should have received copies of the GNU General Public License and
28 : the GNU Lesser General Public License along with this program. If
29 : not, see <http://www.gnu.org/licenses/>. */
30 :
31 : #ifdef HAVE_CONFIG_H
32 : # include <config.h>
33 : #endif
34 :
35 : #include <stdlib.h>
36 : #include <string.h>
37 : #include <sys/types.h>
38 :
39 : #include "md5.h"
40 : #include "system.h"
41 :
42 : #define SWAP(n) LE32 (n)
43 :
44 : /* This array contains the bytes used to pad the buffer to the next
45 : 64-byte boundary. (RFC 1321, 3.1: Step 1) */
46 : static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
47 :
48 :
49 : /* Initialize structure containing state of computation.
50 : (RFC 1321, 3.3: Step 3) */
51 : void
52 4 : md5_init_ctx (struct md5_ctx *ctx)
53 : {
54 4 : ctx->A = 0x67452301;
55 4 : ctx->B = 0xefcdab89;
56 4 : ctx->C = 0x98badcfe;
57 4 : ctx->D = 0x10325476;
58 :
59 4 : ctx->total[0] = ctx->total[1] = 0;
60 4 : ctx->buflen = 0;
61 4 : }
62 :
63 : /* Put result from CTX in first 16 bytes following RESBUF. The result
64 : must be in little endian byte order.
65 :
66 : IMPORTANT: On some systems it is required that RESBUF is correctly
67 : aligned for a 32 bits value. */
68 : void *
69 4 : md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
70 : {
71 4 : ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
72 4 : ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
73 4 : ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
74 4 : ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
75 :
76 4 : return resbuf;
77 : }
78 :
79 : static void
80 : le64_copy (char *dest, uint64_t x)
81 : {
82 32 : for (size_t i = 0; i < 8; ++i)
83 : {
84 32 : dest[i] = (uint8_t) x;
85 32 : x >>= 8;
86 : }
87 : }
88 :
89 : /* Process the remaining bytes in the internal buffer and the usual
90 : prolog according to the standard and write the result to RESBUF.
91 :
92 : IMPORTANT: On some systems it is required that RESBUF is correctly
93 : aligned for a 32 bits value. */
94 : void *
95 4 : md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
96 : {
97 : /* Take yet unprocessed bytes into account. */
98 4 : md5_uint32 bytes = ctx->buflen;
99 : size_t pad;
100 :
101 : /* Now count remaining bytes. */
102 4 : ctx->total[0] += bytes;
103 4 : if (ctx->total[0] < bytes)
104 0 : ++ctx->total[1];
105 :
106 4 : pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
107 8 : memcpy (&ctx->buffer[bytes], fillbuf, pad);
108 :
109 : /* Put the 64-bit file length in *bits* at the end of the buffer. */
110 8 : const uint64_t bit_length = ((ctx->total[0] << 3)
111 8 : + ((uint64_t) ((ctx->total[1] << 3) |
112 8 : (ctx->total[0] >> 29)) << 32));
113 8 : le64_copy (&ctx->buffer[bytes + pad], bit_length);
114 :
115 : /* Process last bytes. */
116 4 : md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
117 :
118 4 : return md5_read_ctx (ctx, resbuf);
119 : }
120 :
121 :
122 : #ifdef NEED_MD5_STREAM
123 : /* Compute MD5 message digest for bytes read from STREAM. The
124 : resulting message digest number will be written into the 16 bytes
125 : beginning at RESBLOCK. */
126 : int
127 : md5_stream (FILE *stream, void *resblock)
128 : {
129 : /* Important: BLOCKSIZE must be a multiple of 64. */
130 : #define BLOCKSIZE 4096
131 : struct md5_ctx ctx;
132 : char buffer[BLOCKSIZE + 72];
133 : size_t sum;
134 :
135 : /* Initialize the computation context. */
136 : md5_init_ctx (&ctx);
137 :
138 : /* Iterate over full file contents. */
139 : while (1)
140 : {
141 : /* We read the file in blocks of BLOCKSIZE bytes. One call of the
142 : computation function processes the whole buffer so that with the
143 : next round of the loop another block can be read. */
144 : size_t n;
145 : sum = 0;
146 :
147 : /* Read block. Take care for partial reads. */
148 : do
149 : {
150 : n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
151 :
152 : sum += n;
153 : }
154 : while (sum < BLOCKSIZE && n != 0);
155 : if (n == 0 && ferror (stream))
156 : return 1;
157 :
158 : /* If end of file is reached, end the loop. */
159 : if (n == 0)
160 : break;
161 :
162 : /* Process buffer with BLOCKSIZE bytes. Note that
163 : BLOCKSIZE % 64 == 0
164 : */
165 : md5_process_block (buffer, BLOCKSIZE, &ctx);
166 : }
167 :
168 : /* Add the last bytes if necessary. */
169 : if (sum > 0)
170 : md5_process_bytes (buffer, sum, &ctx);
171 :
172 : /* Construct result in desired memory. */
173 : md5_finish_ctx (&ctx, resblock);
174 : return 0;
175 : }
176 : #endif
177 :
178 :
179 : #ifdef NEED_MD5_BUFFER
180 : /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
181 : result is always in little endian byte order, so that a byte-wise
182 : output yields to the wanted ASCII representation of the message
183 : digest. */
184 : void *
185 : md5_buffer (const char *buffer, size_t len, void *resblock)
186 : {
187 : struct md5_ctx ctx;
188 :
189 : /* Initialize the computation context. */
190 : md5_init_ctx (&ctx);
191 :
192 : /* Process whole buffer but last len % 64 bytes. */
193 : md5_process_bytes (buffer, len, &ctx);
194 :
195 : /* Put result in desired memory area. */
196 : return md5_finish_ctx (&ctx, resblock);
197 : }
198 : #endif
199 :
200 :
201 : void
202 1003 : md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
203 : {
204 : /* When we already have some bits in our internal buffer concatenate
205 : both inputs first. */
206 1003 : if (ctx->buflen != 0)
207 : {
208 875 : size_t left_over = ctx->buflen;
209 875 : size_t add = 128 - left_over > len ? len : 128 - left_over;
210 :
211 1750 : memcpy (&ctx->buffer[left_over], buffer, add);
212 875 : ctx->buflen += add;
213 :
214 875 : if (ctx->buflen > 64)
215 : {
216 875 : md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
217 :
218 875 : ctx->buflen &= 63;
219 : /* The regions in the following copy operation cannot overlap. */
220 875 : memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
221 : ctx->buflen);
222 : }
223 :
224 875 : buffer = (const char *) buffer + add;
225 875 : len -= add;
226 : }
227 :
228 : /* Process available complete blocks. */
229 1003 : if (len >= 64)
230 : {
231 : #if !_STRING_ARCH_unaligned
232 : /* To check alignment gcc has an appropriate operator. Other
233 : compilers don't. */
234 : # if __GNUC__ >= 2
235 : # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0)
236 : # else
237 : # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0)
238 : # endif
239 1000 : if (UNALIGNED_P (buffer))
240 0 : while (len > 64)
241 : {
242 0 : md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
243 0 : buffer = (const char *) buffer + 64;
244 0 : len -= 64;
245 : }
246 : else
247 : #endif
248 : {
249 1000 : md5_process_block (buffer, len & ~63, ctx);
250 1000 : buffer = (const char *) buffer + (len & ~63);
251 1000 : len &= 63;
252 : }
253 : }
254 :
255 : /* Move remaining bytes in internal buffer. */
256 1003 : if (len > 0)
257 : {
258 878 : size_t left_over = ctx->buflen;
259 :
260 1756 : memcpy (&ctx->buffer[left_over], buffer, len);
261 878 : left_over += len;
262 878 : if (left_over >= 64)
263 : {
264 0 : md5_process_block (ctx->buffer, 64, ctx);
265 0 : left_over -= 64;
266 0 : memcpy (ctx->buffer, &ctx->buffer[64], left_over);
267 : }
268 878 : ctx->buflen = left_over;
269 : }
270 1003 : }
271 :
272 :
273 : /* These are the four functions used in the four steps of the MD5 algorithm
274 : and defined in the RFC 1321. The first function is a little bit optimized
275 : (as found in Colin Plumbs public domain implementation). */
276 : /* #define FF(b, c, d) ((b & c) | (~b & d)) */
277 : #define FF(b, c, d) (d ^ (b & (c ^ d)))
278 : #define FG(b, c, d) FF (d, b, c)
279 : #define FH(b, c, d) (b ^ c ^ d)
280 : #define FI(b, c, d) (c ^ (b | ~d))
281 :
282 : /* Process LEN bytes of BUFFER, accumulating context into CTX.
283 : It is assumed that LEN % 64 == 0. */
284 :
285 : void
286 1879 : md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
287 : {
288 : md5_uint32 correct_words[16];
289 1879 : const md5_uint32 *words = buffer;
290 1879 : size_t nwords = len / sizeof (md5_uint32);
291 1879 : const md5_uint32 *endp = words + nwords;
292 1879 : md5_uint32 A = ctx->A;
293 1879 : md5_uint32 B = ctx->B;
294 1879 : md5_uint32 C = ctx->C;
295 1879 : md5_uint32 D = ctx->D;
296 :
297 : /* First increment the byte count. RFC 1321 specifies the possible
298 : length of the file up to 2^64 bits. Here we only compute the
299 : number of bytes. Do a double word increment. */
300 1879 : ctx->total[0] += len;
301 1879 : if (ctx->total[0] < len)
302 0 : ++ctx->total[1];
303 :
304 : /* Process all bytes in the buffer with 64 bytes in each round of
305 : the loop. */
306 17509 : while (words < endp)
307 : {
308 15630 : md5_uint32 *cwp = correct_words;
309 15630 : md5_uint32 A_save = A;
310 15630 : md5_uint32 B_save = B;
311 15630 : md5_uint32 C_save = C;
312 15630 : md5_uint32 D_save = D;
313 :
314 : /* First round: using the given function, the context and a constant
315 : the next context is computed. Because the algorithms processing
316 : unit is a 32-bit word and it is determined to work on words in
317 : little endian byte order we perhaps have to change the byte order
318 : before the computation. To reduce the work for the next steps
319 : we store the swapped words in the array CORRECT_WORDS. */
320 :
321 : #define OP(a, b, c, d, s, T) \
322 : do \
323 : { \
324 : a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
325 : ++words; \
326 : CYCLIC (a, s); \
327 : a += b; \
328 : } \
329 : while (0)
330 :
331 : /* It is unfortunate that C does not provide an operator for
332 : cyclic rotation. Hope the C compiler is smart enough. */
333 : #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
334 :
335 : /* Before we start, one word to the strange constants.
336 : They are defined in RFC 1321 as
337 :
338 : T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
339 : */
340 :
341 : /* Round 1. */
342 15630 : OP (A, B, C, D, 7, 0xd76aa478);
343 15630 : OP (D, A, B, C, 12, 0xe8c7b756);
344 15630 : OP (C, D, A, B, 17, 0x242070db);
345 15630 : OP (B, C, D, A, 22, 0xc1bdceee);
346 15630 : OP (A, B, C, D, 7, 0xf57c0faf);
347 15630 : OP (D, A, B, C, 12, 0x4787c62a);
348 15630 : OP (C, D, A, B, 17, 0xa8304613);
349 15630 : OP (B, C, D, A, 22, 0xfd469501);
350 15630 : OP (A, B, C, D, 7, 0x698098d8);
351 15630 : OP (D, A, B, C, 12, 0x8b44f7af);
352 15630 : OP (C, D, A, B, 17, 0xffff5bb1);
353 15630 : OP (B, C, D, A, 22, 0x895cd7be);
354 15630 : OP (A, B, C, D, 7, 0x6b901122);
355 15630 : OP (D, A, B, C, 12, 0xfd987193);
356 15630 : OP (C, D, A, B, 17, 0xa679438e);
357 15630 : OP (B, C, D, A, 22, 0x49b40821);
358 :
359 : /* For the second to fourth round we have the possibly swapped words
360 : in CORRECT_WORDS. Redefine the macro to take an additional first
361 : argument specifying the function to use. */
362 : #undef OP
363 : #define OP(f, a, b, c, d, k, s, T) \
364 : do \
365 : { \
366 : a += f (b, c, d) + correct_words[k] + T; \
367 : CYCLIC (a, s); \
368 : a += b; \
369 : } \
370 : while (0)
371 :
372 : /* Round 2. */
373 15630 : OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
374 15630 : OP (FG, D, A, B, C, 6, 9, 0xc040b340);
375 15630 : OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
376 15630 : OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
377 15630 : OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
378 15630 : OP (FG, D, A, B, C, 10, 9, 0x02441453);
379 15630 : OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
380 15630 : OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
381 15630 : OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
382 15630 : OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
383 15630 : OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
384 15630 : OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
385 15630 : OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
386 15630 : OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
387 15630 : OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
388 15630 : OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
389 :
390 : /* Round 3. */
391 15630 : OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
392 15630 : OP (FH, D, A, B, C, 8, 11, 0x8771f681);
393 15630 : OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
394 15630 : OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
395 15630 : OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
396 15630 : OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
397 15630 : OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
398 15630 : OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
399 15630 : OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
400 15630 : OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
401 15630 : OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
402 15630 : OP (FH, B, C, D, A, 6, 23, 0x04881d05);
403 15630 : OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
404 15630 : OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
405 15630 : OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
406 15630 : OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
407 :
408 : /* Round 4. */
409 15630 : OP (FI, A, B, C, D, 0, 6, 0xf4292244);
410 15630 : OP (FI, D, A, B, C, 7, 10, 0x432aff97);
411 15630 : OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
412 15630 : OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
413 15630 : OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
414 15630 : OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
415 15630 : OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
416 15630 : OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
417 15630 : OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
418 15630 : OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
419 15630 : OP (FI, C, D, A, B, 6, 15, 0xa3014314);
420 15630 : OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
421 15630 : OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
422 15630 : OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
423 15630 : OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
424 15630 : OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
425 :
426 : /* Add the starting values of the context. */
427 15630 : A += A_save;
428 15630 : B += B_save;
429 15630 : C += C_save;
430 15630 : D += D_save;
431 : }
432 :
433 : /* Put checksum in context given as argument. */
434 1879 : ctx->A = A;
435 1879 : ctx->B = B;
436 1879 : ctx->C = C;
437 1879 : ctx->D = D;
438 1879 : }
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