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 Red Hat, Inc.
4 This file is part of Red Hat elfutils.
5 Written by Ulrich Drepper <drepper@redhat.com>, 1995.
6
7 Red Hat elfutils is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by the
9 Free Software Foundation; version 2 of the License.
10
11 Red Hat elfutils is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU General Public License along
17 with Red Hat elfutils; if not, write to the Free Software Foundation,
18 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
19
20 Red Hat elfutils is an included package of the Open Invention Network.
21 An included package of the Open Invention Network is a package for which
22 Open Invention Network licensees cross-license their patents. No patent
23 license is granted, either expressly or impliedly, by designation as an
24 included package. Should you wish to participate in the Open Invention
25 Network licensing program, please visit www.openinventionnetwork.com
26 <http://www.openinventionnetwork.com>. */
27
28 #ifdef HAVE_CONFIG_H
29 # include <config.h>
30 #endif
31
32 #include <stdlib.h>
33 #include <string.h>
34 #include <sys/types.h>
35
36 #include "md5.h"
37 #include "system.h"
38
39 #define SWAP(n) LE32 (n)
40
41 /* This array contains the bytes used to pad the buffer to the next
42 64-byte boundary. (RFC 1321, 3.1: Step 1) */
43 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
44
45
46 /* Initialize structure containing state of computation.
47 (RFC 1321, 3.3: Step 3) */
48 void
md5_init_ctx(ctx)49 md5_init_ctx (ctx)
50 struct md5_ctx *ctx;
51 {
52 ctx->A = 0x67452301;
53 ctx->B = 0xefcdab89;
54 ctx->C = 0x98badcfe;
55 ctx->D = 0x10325476;
56
57 ctx->total[0] = ctx->total[1] = 0;
58 ctx->buflen = 0;
59 }
60
61 /* Put result from CTX in first 16 bytes following RESBUF. The result
62 must be in little endian byte order.
63
64 IMPORTANT: On some systems it is required that RESBUF is correctly
65 aligned for a 32 bits value. */
66 void *
md5_read_ctx(ctx,resbuf)67 md5_read_ctx (ctx, resbuf)
68 const struct md5_ctx *ctx;
69 void *resbuf;
70 {
71 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
72 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
73 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
74 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
75
76 return resbuf;
77 }
78
79 static void
le64_copy(char * dest,uint64_t x)80 le64_copy (char *dest, uint64_t x)
81 {
82 for (size_t i = 0; i < 8; ++i)
83 {
84 dest[i] = (uint8_t) x;
85 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 *
md5_finish_ctx(ctx,resbuf)95 md5_finish_ctx (ctx, resbuf)
96 struct md5_ctx *ctx;
97 void *resbuf;
98 {
99 /* Take yet unprocessed bytes into account. */
100 md5_uint32 bytes = ctx->buflen;
101 size_t pad;
102
103 /* Now count remaining bytes. */
104 ctx->total[0] += bytes;
105 if (ctx->total[0] < bytes)
106 ++ctx->total[1];
107
108 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
109 memcpy (&ctx->buffer[bytes], fillbuf, pad);
110
111 /* Put the 64-bit file length in *bits* at the end of the buffer. */
112 const uint64_t bit_length = ((ctx->total[0] << 3)
113 + ((uint64_t) ((ctx->total[1] << 3) |
114 (ctx->total[0] >> 29)) << 32));
115 le64_copy (&ctx->buffer[bytes + pad], bit_length);
116
117 /* Process last bytes. */
118 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
119
120 return md5_read_ctx (ctx, resbuf);
121 }
122
123
124 #ifdef NEED_MD5_STREAM
125 /* Compute MD5 message digest for bytes read from STREAM. The
126 resulting message digest number will be written into the 16 bytes
127 beginning at RESBLOCK. */
128 int
md5_stream(stream,resblock)129 md5_stream (stream, resblock)
130 FILE *stream;
131 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 #endif
181
182
183 #ifdef NEED_MD5_BUFFER
184 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
185 result is always in little endian byte order, so that a byte-wise
186 output yields to the wanted ASCII representation of the message
187 digest. */
188 void *
md5_buffer(buffer,len,resblock)189 md5_buffer (buffer, len, resblock)
190 const char *buffer;
191 size_t len;
192 void *resblock;
193 {
194 struct md5_ctx ctx;
195
196 /* Initialize the computation context. */
197 md5_init_ctx (&ctx);
198
199 /* Process whole buffer but last len % 64 bytes. */
200 md5_process_bytes (buffer, len, &ctx);
201
202 /* Put result in desired memory area. */
203 return md5_finish_ctx (&ctx, resblock);
204 }
205 #endif
206
207
208 void
md5_process_bytes(buffer,len,ctx)209 md5_process_bytes (buffer, len, ctx)
210 const void *buffer;
211 size_t len;
212 struct md5_ctx *ctx;
213 {
214 /* When we already have some bits in our internal buffer concatenate
215 both inputs first. */
216 if (ctx->buflen != 0)
217 {
218 size_t left_over = ctx->buflen;
219 size_t add = 128 - left_over > len ? len : 128 - left_over;
220
221 memcpy (&ctx->buffer[left_over], buffer, add);
222 ctx->buflen += add;
223
224 if (ctx->buflen > 64)
225 {
226 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
227
228 ctx->buflen &= 63;
229 /* The regions in the following copy operation cannot overlap. */
230 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
231 ctx->buflen);
232 }
233
234 buffer = (const char *) buffer + add;
235 len -= add;
236 }
237
238 /* Process available complete blocks. */
239 if (len >= 64)
240 {
241 #if !_STRING_ARCH_unaligned
242 /* To check alignment gcc has an appropriate operator. Other
243 compilers don't. */
244 # if __GNUC__ >= 2
245 # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0)
246 # else
247 # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0)
248 # endif
249 if (UNALIGNED_P (buffer))
250 while (len > 64)
251 {
252 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
253 buffer = (const char *) buffer + 64;
254 len -= 64;
255 }
256 else
257 #endif
258 {
259 md5_process_block (buffer, len & ~63, ctx);
260 buffer = (const char *) buffer + (len & ~63);
261 len &= 63;
262 }
263 }
264
265 /* Move remaining bytes in internal buffer. */
266 if (len > 0)
267 {
268 size_t left_over = ctx->buflen;
269
270 memcpy (&ctx->buffer[left_over], buffer, len);
271 left_over += len;
272 if (left_over >= 64)
273 {
274 md5_process_block (ctx->buffer, 64, ctx);
275 left_over -= 64;
276 memcpy (ctx->buffer, &ctx->buffer[64], left_over);
277 }
278 ctx->buflen = left_over;
279 }
280 }
281
282
283 /* These are the four functions used in the four steps of the MD5 algorithm
284 and defined in the RFC 1321. The first function is a little bit optimized
285 (as found in Colin Plumbs public domain implementation). */
286 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
287 #define FF(b, c, d) (d ^ (b & (c ^ d)))
288 #define FG(b, c, d) FF (d, b, c)
289 #define FH(b, c, d) (b ^ c ^ d)
290 #define FI(b, c, d) (c ^ (b | ~d))
291
292 /* Process LEN bytes of BUFFER, accumulating context into CTX.
293 It is assumed that LEN % 64 == 0. */
294
295 void
md5_process_block(buffer,len,ctx)296 md5_process_block (buffer, len, ctx)
297 const void *buffer;
298 size_t len;
299 struct md5_ctx *ctx;
300 {
301 md5_uint32 correct_words[16];
302 const md5_uint32 *words = buffer;
303 size_t nwords = len / sizeof (md5_uint32);
304 const md5_uint32 *endp = words + nwords;
305 md5_uint32 A = ctx->A;
306 md5_uint32 B = ctx->B;
307 md5_uint32 C = ctx->C;
308 md5_uint32 D = ctx->D;
309
310 /* First increment the byte count. RFC 1321 specifies the possible
311 length of the file up to 2^64 bits. Here we only compute the
312 number of bytes. Do a double word increment. */
313 ctx->total[0] += len;
314 if (ctx->total[0] < len)
315 ++ctx->total[1];
316
317 /* Process all bytes in the buffer with 64 bytes in each round of
318 the loop. */
319 while (words < endp)
320 {
321 md5_uint32 *cwp = correct_words;
322 md5_uint32 A_save = A;
323 md5_uint32 B_save = B;
324 md5_uint32 C_save = C;
325 md5_uint32 D_save = D;
326
327 /* First round: using the given function, the context and a constant
328 the next context is computed. Because the algorithms processing
329 unit is a 32-bit word and it is determined to work on words in
330 little endian byte order we perhaps have to change the byte order
331 before the computation. To reduce the work for the next steps
332 we store the swapped words in the array CORRECT_WORDS. */
333
334 #define OP(a, b, c, d, s, T) \
335 do \
336 { \
337 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
338 ++words; \
339 CYCLIC (a, s); \
340 a += b; \
341 } \
342 while (0)
343
344 /* It is unfortunate that C does not provide an operator for
345 cyclic rotation. Hope the C compiler is smart enough. */
346 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
347
348 /* Before we start, one word to the strange constants.
349 They are defined in RFC 1321 as
350
351 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
352 */
353
354 /* Round 1. */
355 OP (A, B, C, D, 7, 0xd76aa478);
356 OP (D, A, B, C, 12, 0xe8c7b756);
357 OP (C, D, A, B, 17, 0x242070db);
358 OP (B, C, D, A, 22, 0xc1bdceee);
359 OP (A, B, C, D, 7, 0xf57c0faf);
360 OP (D, A, B, C, 12, 0x4787c62a);
361 OP (C, D, A, B, 17, 0xa8304613);
362 OP (B, C, D, A, 22, 0xfd469501);
363 OP (A, B, C, D, 7, 0x698098d8);
364 OP (D, A, B, C, 12, 0x8b44f7af);
365 OP (C, D, A, B, 17, 0xffff5bb1);
366 OP (B, C, D, A, 22, 0x895cd7be);
367 OP (A, B, C, D, 7, 0x6b901122);
368 OP (D, A, B, C, 12, 0xfd987193);
369 OP (C, D, A, B, 17, 0xa679438e);
370 OP (B, C, D, A, 22, 0x49b40821);
371
372 /* For the second to fourth round we have the possibly swapped words
373 in CORRECT_WORDS. Redefine the macro to take an additional first
374 argument specifying the function to use. */
375 #undef OP
376 #define OP(f, a, b, c, d, k, s, T) \
377 do \
378 { \
379 a += f (b, c, d) + correct_words[k] + T; \
380 CYCLIC (a, s); \
381 a += b; \
382 } \
383 while (0)
384
385 /* Round 2. */
386 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
387 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
388 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
389 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
390 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
391 OP (FG, D, A, B, C, 10, 9, 0x02441453);
392 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
393 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
394 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
395 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
396 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
397 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
398 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
399 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
400 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
401 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
402
403 /* Round 3. */
404 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
405 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
406 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
407 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
408 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
409 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
410 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
411 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
412 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
413 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
414 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
415 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
416 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
417 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
418 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
419 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
420
421 /* Round 4. */
422 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
423 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
424 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
425 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
426 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
427 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
428 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
429 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
430 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
431 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
432 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
433 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
434 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
435 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
436 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
437 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
438
439 /* Add the starting values of the context. */
440 A += A_save;
441 B += B_save;
442 C += C_save;
443 D += D_save;
444 }
445
446 /* Put checksum in context given as argument. */
447 ctx->A = A;
448 ctx->B = B;
449 ctx->C = C;
450 ctx->D = D;
451 }
452