src/mn-md5.c (11232B) - raw
1 /*
2 * MD5 message digest implementation, taken from glibc and edited for
3 * style.
4 *
5 * The GNU C Library,
6 * Copyright (C) 1995,1996,1997,1999,2000,2001,2005
7 * Free Software Foundation, Inc.
8 *
9 * Mail Notification
10 * Copyright (C) 2003-2008 Jean-Yves Lefort <jylefort@brutele.be>
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 3 of the License, or
15 * (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License along
23 * with this program; if not, write to the Free Software Foundation, Inc.,
24 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
25 */
26
27 #include <sys/types.h>
28 #include <string.h>
29 #include "mn-md5.h"
30
31 #ifdef WORDS_BIGENDIAN
32 # define SWAP(n) \
33 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
34 #else
35 # define SWAP(n) (n)
36 #endif
37
38 #define HEXCHARS "0123456789abcdef"
39
40 /* This array contains the bytes used to pad the buffer to the next
41 64-byte boundary. (RFC 1321, 3.1: Step 1) */
42 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
43
44
45 /* Initialize structure containing state of computation.
46 (RFC 1321, 3.3: Step 3) */
47 void
48 mn_md5_init_ctx (MNMD5Context *ctx)
49 {
50 ctx->A = 0x67452301;
51 ctx->B = 0xefcdab89;
52 ctx->C = 0x98badcfe;
53 ctx->D = 0x10325476;
54
55 ctx->total[0] = ctx->total[1] = 0;
56 ctx->buflen = 0;
57 }
58
59 /* Put result from CTX in first 16 bytes following RESBUF. The result
60 must be in little endian byte order.
61
62 IMPORTANT: On some systems it is required that RESBUF is correctly
63 aligned for a 32 bits value. */
64 void *
65 mn_md5_read_ctx (MNMD5Context *ctx, void *resbuf)
66 {
67 ((uint32_t *) resbuf)[0] = SWAP (ctx->A);
68 ((uint32_t *) resbuf)[1] = SWAP (ctx->B);
69 ((uint32_t *) resbuf)[2] = SWAP (ctx->C);
70 ((uint32_t *) resbuf)[3] = SWAP (ctx->D);
71
72 return resbuf;
73 }
74
75 /* Process the remaining bytes in the internal buffer and the usual
76 prolog according to the standard and write the result to RESBUF.
77
78 IMPORTANT: On some systems it is required that RESBUF is correctly
79 aligned for a 32 bits value. */
80 void *
81 mn_md5_finish_ctx (MNMD5Context *ctx, unsigned char resbuf[16])
82 {
83 /* Take yet unprocessed bytes into account. */
84 uint32_t bytes = ctx->buflen;
85 size_t pad;
86
87 /* Now count remaining bytes. */
88 ctx->total[0] += bytes;
89 if (ctx->total[0] < bytes)
90 ++ctx->total[1];
91
92 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
93 memcpy (&ctx->buffer[bytes], fillbuf, pad);
94
95 /* Put the 64-bit file length in *bits* at the end of the buffer. */
96 *(uint32_t *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
97 *(uint32_t *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
98 (ctx->total[0] >> 29));
99
100 /* Process last bytes. */
101 mn_md5_process_block (ctx, ctx->buffer, bytes + pad + 8);
102
103 return mn_md5_read_ctx (ctx, resbuf);
104 }
105
106 void
107 mn_md5_to_hex (const unsigned char resbuf[16], char hexbuf[33])
108 {
109 int i;
110
111 for (i = 0; i < 16; i++)
112 {
113 hexbuf[i * 2] = HEXCHARS[resbuf[i] >> 4];
114 hexbuf[i * 2 + 1] = HEXCHARS[resbuf[i] & 0xf];
115 }
116
117 hexbuf[32] = 0;
118 }
119
120 void
121 mn_md5_process_bytes (MNMD5Context *ctx, const void *buffer, size_t len)
122 {
123 /* When we already have some bits in our internal buffer concatenate
124 both inputs first. */
125 if (ctx->buflen != 0)
126 {
127 size_t left_over = ctx->buflen;
128 size_t add = 128 - left_over > len ? len : 128 - left_over;
129
130 memcpy (&ctx->buffer[left_over], buffer, add);
131 ctx->buflen += add;
132
133 if (ctx->buflen > 64)
134 {
135 mn_md5_process_block (ctx, ctx->buffer, ctx->buflen & ~63);
136
137 ctx->buflen &= 63;
138 /* The regions in the following copy operation cannot overlap. */
139 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
140 ctx->buflen);
141 }
142
143 buffer = (const char *) buffer + add;
144 len -= add;
145 }
146
147 /* Process available complete blocks. */
148 if (len >= 64)
149 {
150 #ifndef STRING_ARCH_UNALIGNED
151 /* To check alignment gcc has an appropriate operator. Other
152 compilers don't. */
153 # if __GNUC__ >= 2
154 # define UNALIGNED_P(p) (((uintptr_t) p) % __alignof__ (uint32_t) != 0)
155 # else
156 # define UNALIGNED_P(p) (((uintptr_t) p) % sizeof (uint32_t) != 0)
157 # endif
158 if (UNALIGNED_P (buffer))
159 while (len > 64)
160 {
161 mn_md5_process_block (ctx, memcpy (ctx->buffer, buffer, 64), 64);
162 buffer = (const char *) buffer + 64;
163 len -= 64;
164 }
165 else
166 #endif
167 {
168 mn_md5_process_block (ctx, buffer, len & ~63);
169 buffer = (const char *) buffer + (len & ~63);
170 len &= 63;
171 }
172 }
173
174 /* Move remaining bytes in internal buffer. */
175 if (len > 0)
176 {
177 size_t left_over = ctx->buflen;
178
179 memcpy (&ctx->buffer[left_over], buffer, len);
180 left_over += len;
181 if (left_over >= 64)
182 {
183 mn_md5_process_block (ctx, ctx->buffer, 64);
184 left_over -= 64;
185 memcpy (ctx->buffer, &ctx->buffer[64], left_over);
186 }
187 ctx->buflen = left_over;
188 }
189 }
190
191
192 /* These are the four functions used in the four steps of the MD5 algorithm
193 and defined in the RFC 1321. The first function is a little bit optimized
194 (as found in Colin Plumbs public domain implementation). */
195 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
196 #define FF(b, c, d) (d ^ (b & (c ^ d)))
197 #define FG(b, c, d) FF (d, b, c)
198 #define FH(b, c, d) (b ^ c ^ d)
199 #define FI(b, c, d) (c ^ (b | ~d))
200
201 /* Process LEN bytes of BUFFER, accumulating context into CTX.
202 It is assumed that LEN % 64 == 0. */
203
204 void
205 mn_md5_process_block (MNMD5Context *ctx, const void *buffer, size_t len)
206 {
207 uint32_t correct_words[16];
208 const uint32_t *words = buffer;
209 size_t nwords = len / sizeof (uint32_t);
210 const uint32_t *endp = words + nwords;
211 uint32_t A = ctx->A;
212 uint32_t B = ctx->B;
213 uint32_t C = ctx->C;
214 uint32_t D = ctx->D;
215
216 /* First increment the byte count. RFC 1321 specifies the possible
217 length of the file up to 2^64 bits. Here we only compute the
218 number of bytes. Do a double word increment. */
219 ctx->total[0] += len;
220 if (ctx->total[0] < len)
221 ++ctx->total[1];
222
223 /* Process all bytes in the buffer with 64 bytes in each round of
224 the loop. */
225 while (words < endp)
226 {
227 uint32_t *cwp = correct_words;
228 uint32_t A_save = A;
229 uint32_t B_save = B;
230 uint32_t C_save = C;
231 uint32_t D_save = D;
232
233 /* First round: using the given function, the context and a constant
234 the next context is computed. Because the algorithms processing
235 unit is a 32-bit word and it is determined to work on words in
236 little endian byte order we perhaps have to change the byte order
237 before the computation. To reduce the work for the next steps
238 we store the swapped words in the array CORRECT_WORDS. */
239
240 #define OP(a, b, c, d, s, T) \
241 do \
242 { \
243 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
244 ++words; \
245 CYCLIC (a, s); \
246 a += b; \
247 } \
248 while (0)
249
250 /* It is unfortunate that C does not provide an operator for
251 cyclic rotation. Hope the C compiler is smart enough. */
252 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
253
254 /* Before we start, one word to the strange constants.
255 They are defined in RFC 1321 as
256
257 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
258 */
259
260 /* Round 1. */
261 OP (A, B, C, D, 7, 0xd76aa478);
262 OP (D, A, B, C, 12, 0xe8c7b756);
263 OP (C, D, A, B, 17, 0x242070db);
264 OP (B, C, D, A, 22, 0xc1bdceee);
265 OP (A, B, C, D, 7, 0xf57c0faf);
266 OP (D, A, B, C, 12, 0x4787c62a);
267 OP (C, D, A, B, 17, 0xa8304613);
268 OP (B, C, D, A, 22, 0xfd469501);
269 OP (A, B, C, D, 7, 0x698098d8);
270 OP (D, A, B, C, 12, 0x8b44f7af);
271 OP (C, D, A, B, 17, 0xffff5bb1);
272 OP (B, C, D, A, 22, 0x895cd7be);
273 OP (A, B, C, D, 7, 0x6b901122);
274 OP (D, A, B, C, 12, 0xfd987193);
275 OP (C, D, A, B, 17, 0xa679438e);
276 OP (B, C, D, A, 22, 0x49b40821);
277
278 /* For the second to fourth round we have the possibly swapped words
279 in CORRECT_WORDS. Redefine the macro to take an additional first
280 argument specifying the function to use. */
281 #undef OP
282 #define OP(f, a, b, c, d, k, s, T) \
283 do \
284 { \
285 a += f (b, c, d) + correct_words[k] + T; \
286 CYCLIC (a, s); \
287 a += b; \
288 } \
289 while (0)
290
291 /* Round 2. */
292 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
293 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
294 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
295 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
296 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
297 OP (FG, D, A, B, C, 10, 9, 0x02441453);
298 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
299 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
300 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
301 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
302 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
303 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
304 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
305 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
306 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
307 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
308
309 /* Round 3. */
310 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
311 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
312 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
313 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
314 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
315 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
316 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
317 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
318 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
319 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
320 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
321 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
322 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
323 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
324 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
325 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
326
327 /* Round 4. */
328 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
329 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
330 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
331 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
332 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
333 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
334 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
335 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
336 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
337 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
338 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
339 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
340 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
341 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
342 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
343 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
344
345 /* Add the starting values of the context. */
346 A += A_save;
347 B += B_save;
348 C += C_save;
349 D += D_save;
350 }
351
352 /* Put checksum in context given as argument. */
353 ctx->A = A;
354 ctx->B = B;
355 ctx->C = C;
356 ctx->D = D;
357 }