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, 1996, 1997, 1999, 2000 Free Software Foundation, Inc.
4 This file is part of the GNU Emacs.
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.
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.
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. */
21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
27 #include <sys/types.h>
29 #if STDC_HEADERS || defined _LIBC
34 # define memcpy(d, s, n) bcopy ((s), (d), (n))
40 # if __BYTE_ORDER == __BIG_ENDIAN
41 # define WORDS_BIGENDIAN 1
43 /* We need to keep the namespace clean so define the MD5 function
44 protected using leading __ . */
45 # define md5_init_ctx __md5_init_ctx
46 # define md5_process_block __md5_process_block
47 # define md5_process_bytes __md5_process_bytes
48 # define md5_finish_ctx __md5_finish_ctx
49 # define md5_read_ctx __md5_read_ctx
50 # define md5_stream __md5_stream
51 # define md5_buffer __md5_buffer
56 #ifdef WORDS_BIGENDIAN
58 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
64 /* This array contains the bytes used to pad the buffer to the next
65 64-byte boundary. (RFC 1321, 3.1: Step 1) */
66 static const unsigned char fillbuf
[64] = { 0x80, 0 /* , 0, 0, ... */ };
69 /* Initialize structure containing state of computation.
70 (RFC 1321, 3.3: Step 3) */
80 ctx
->total
[0] = ctx
->total
[1] = 0;
84 /* Put result from CTX in first 16 bytes following RESBUF. The result
85 must be in little endian byte order.
87 IMPORTANT: On some systems it is required that RESBUF is correctly
88 aligned for a 32 bits value. */
90 md5_read_ctx (ctx
, resbuf
)
91 const struct md5_ctx
*ctx
;
94 ((md5_uint32
*) resbuf
)[0] = SWAP (ctx
->A
);
95 ((md5_uint32
*) resbuf
)[1] = SWAP (ctx
->B
);
96 ((md5_uint32
*) resbuf
)[2] = SWAP (ctx
->C
);
97 ((md5_uint32
*) resbuf
)[3] = SWAP (ctx
->D
);
102 /* Process the remaining bytes in the internal buffer and the usual
103 prolog according to the standard and write the result to RESBUF.
105 IMPORTANT: On some systems it is required that RESBUF is correctly
106 aligned for a 32 bits value. */
108 md5_finish_ctx (ctx
, resbuf
)
112 /* Take yet unprocessed bytes into account. */
113 md5_uint32 bytes
= ctx
->buflen
;
116 /* Now count remaining bytes. */
117 ctx
->total
[0] += bytes
;
118 if (ctx
->total
[0] < bytes
)
121 pad
= bytes
>= 56 ? 64 + 56 - bytes
: 56 - bytes
;
122 memcpy (&ctx
->buffer
[bytes
], fillbuf
, pad
);
124 /* Put the 64-bit file length in *bits* at the end of the buffer. */
125 *(md5_uint32
*) &ctx
->buffer
[bytes
+ pad
] = SWAP (ctx
->total
[0] << 3);
126 *(md5_uint32
*) &ctx
->buffer
[bytes
+ pad
+ 4] = SWAP ((ctx
->total
[1] << 3) |
127 (ctx
->total
[0] >> 29));
129 /* Process last bytes. */
130 md5_process_block (ctx
->buffer
, bytes
+ pad
+ 8, ctx
);
132 return md5_read_ctx (ctx
, resbuf
);
135 /* Compute MD5 message digest for bytes read from STREAM. The
136 resulting message digest number will be written into the 16 bytes
137 beginning at RESBLOCK. */
139 md5_stream (stream
, resblock
)
143 /* Important: BLOCKSIZE must be a multiple of 64. */
144 #define BLOCKSIZE 4096
146 char buffer
[BLOCKSIZE
+ 72];
149 /* Initialize the computation context. */
152 /* Iterate over full file contents. */
155 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
156 computation function processes the whole buffer so that with the
157 next round of the loop another block can be read. */
161 /* Read block. Take care for partial reads. */
164 n
= fread (buffer
+ sum
, 1, BLOCKSIZE
- sum
, stream
);
168 while (sum
< BLOCKSIZE
&& n
!= 0);
169 if (n
== 0 && ferror (stream
))
172 /* If end of file is reached, end the loop. */
176 /* Process buffer with BLOCKSIZE bytes. Note that
179 md5_process_block (buffer
, BLOCKSIZE
, &ctx
);
182 /* Add the last bytes if necessary. */
184 md5_process_bytes (buffer
, sum
, &ctx
);
186 /* Construct result in desired memory. */
187 md5_finish_ctx (&ctx
, resblock
);
191 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
192 result is always in little endian byte order, so that a byte-wise
193 output yields to the wanted ASCII representation of the message
196 md5_buffer (buffer
, len
, resblock
)
203 /* Initialize the computation context. */
206 /* Process whole buffer but last len % 64 bytes. */
207 md5_process_bytes (buffer
, len
, &ctx
);
209 /* Put result in desired memory area. */
210 return md5_finish_ctx (&ctx
, resblock
);
215 md5_process_bytes (buffer
, len
, ctx
)
220 /* const void aligned_buffer = buffer; */
222 /* When we already have some bits in our internal buffer concatenate
223 both inputs first. */
224 if (ctx
->buflen
!= 0)
226 size_t left_over
= ctx
->buflen
;
227 size_t add
= 128 - left_over
> len
? len
: 128 - left_over
;
229 /* Only put full words in the buffer. */
230 add
-= add
% __alignof__ (md5_uint32
);
232 memcpy (&ctx
->buffer
[left_over
], buffer
, add
);
235 if (ctx
->buflen
> 64)
237 md5_process_block (ctx
->buffer
, ctx
->buflen
& ~63, ctx
);
240 /* The regions in the following copy operation cannot overlap. */
241 memcpy (ctx
->buffer
, &ctx
->buffer
[(left_over
+ add
) & ~63],
245 buffer
= (const char *) buffer
+ add
;
249 /* Process available complete blocks. */
252 md5_process_block (buffer
, len
& ~63, ctx
);
253 buffer
= (const char *) buffer
+ (len
& ~63);
257 /* Move remaining bytes in internal buffer. */
260 size_t left_over
= ctx
->buflen
;
262 memcpy (&ctx
->buffer
[left_over
], buffer
, len
);
266 md5_process_block (ctx
->buffer
, 64, ctx
);
268 memcpy (ctx
->buffer
, &ctx
->buffer
[64], left_over
);
270 ctx
->buflen
= left_over
;
275 /* These are the four functions used in the four steps of the MD5 algorithm
276 and defined in the RFC 1321. The first function is a little bit optimized
277 (as found in Colin Plumbs public domain implementation). */
278 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
279 #define FF(b, c, d) (d ^ (b & (c ^ d)))
280 #define FG(b, c, d) FF (d, b, c)
281 #define FH(b, c, d) (b ^ c ^ d)
282 #define FI(b, c, d) (c ^ (b | ~d))
284 /* Process LEN bytes of BUFFER, accumulating context into CTX.
285 It is assumed that LEN % 64 == 0. */
288 md5_process_block (buffer
, len
, ctx
)
293 md5_uint32 correct_words
[16];
294 const md5_uint32
*words
= buffer
;
295 size_t nwords
= len
/ sizeof (md5_uint32
);
296 const md5_uint32
*endp
= words
+ nwords
;
297 md5_uint32 A
= ctx
->A
;
298 md5_uint32 B
= ctx
->B
;
299 md5_uint32 C
= ctx
->C
;
300 md5_uint32 D
= ctx
->D
;
302 /* First increment the byte count. RFC 1321 specifies the possible
303 length of the file up to 2^64 bits. Here we only compute the
304 number of bytes. Do a double word increment. */
305 ctx
->total
[0] += len
;
306 if (ctx
->total
[0] < len
)
309 /* Process all bytes in the buffer with 64 bytes in each round of
313 md5_uint32
*cwp
= correct_words
;
314 md5_uint32 A_save
= A
;
315 md5_uint32 B_save
= B
;
316 md5_uint32 C_save
= C
;
317 md5_uint32 D_save
= D
;
319 /* First round: using the given function, the context and a constant
320 the next context is computed. Because the algorithms processing
321 unit is a 32-bit word and it is determined to work on words in
322 little endian byte order we perhaps have to change the byte order
323 before the computation. To reduce the work for the next steps
324 we store the swapped words in the array CORRECT_WORDS. */
326 #define OP(a, b, c, d, s, T) \
329 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
336 /* It is unfortunate that C does not provide an operator for
337 cyclic rotation. Hope the C compiler is smart enough. */
338 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
340 /* Before we start, one word to the strange constants.
341 They are defined in RFC 1321 as
343 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
347 OP (A
, B
, C
, D
, 7, 0xd76aa478);
348 OP (D
, A
, B
, C
, 12, 0xe8c7b756);
349 OP (C
, D
, A
, B
, 17, 0x242070db);
350 OP (B
, C
, D
, A
, 22, 0xc1bdceee);
351 OP (A
, B
, C
, D
, 7, 0xf57c0faf);
352 OP (D
, A
, B
, C
, 12, 0x4787c62a);
353 OP (C
, D
, A
, B
, 17, 0xa8304613);
354 OP (B
, C
, D
, A
, 22, 0xfd469501);
355 OP (A
, B
, C
, D
, 7, 0x698098d8);
356 OP (D
, A
, B
, C
, 12, 0x8b44f7af);
357 OP (C
, D
, A
, B
, 17, 0xffff5bb1);
358 OP (B
, C
, D
, A
, 22, 0x895cd7be);
359 OP (A
, B
, C
, D
, 7, 0x6b901122);
360 OP (D
, A
, B
, C
, 12, 0xfd987193);
361 OP (C
, D
, A
, B
, 17, 0xa679438e);
362 OP (B
, C
, D
, A
, 22, 0x49b40821);
364 /* For the second to fourth round we have the possibly swapped words
365 in CORRECT_WORDS. Redefine the macro to take an additional first
366 argument specifying the function to use. */
368 #define OP(f, a, b, c, d, k, s, T) \
371 a += f (b, c, d) + correct_words[k] + T; \
378 OP (FG
, A
, B
, C
, D
, 1, 5, 0xf61e2562);
379 OP (FG
, D
, A
, B
, C
, 6, 9, 0xc040b340);
380 OP (FG
, C
, D
, A
, B
, 11, 14, 0x265e5a51);
381 OP (FG
, B
, C
, D
, A
, 0, 20, 0xe9b6c7aa);
382 OP (FG
, A
, B
, C
, D
, 5, 5, 0xd62f105d);
383 OP (FG
, D
, A
, B
, C
, 10, 9, 0x02441453);
384 OP (FG
, C
, D
, A
, B
, 15, 14, 0xd8a1e681);
385 OP (FG
, B
, C
, D
, A
, 4, 20, 0xe7d3fbc8);
386 OP (FG
, A
, B
, C
, D
, 9, 5, 0x21e1cde6);
387 OP (FG
, D
, A
, B
, C
, 14, 9, 0xc33707d6);
388 OP (FG
, C
, D
, A
, B
, 3, 14, 0xf4d50d87);
389 OP (FG
, B
, C
, D
, A
, 8, 20, 0x455a14ed);
390 OP (FG
, A
, B
, C
, D
, 13, 5, 0xa9e3e905);
391 OP (FG
, D
, A
, B
, C
, 2, 9, 0xfcefa3f8);
392 OP (FG
, C
, D
, A
, B
, 7, 14, 0x676f02d9);
393 OP (FG
, B
, C
, D
, A
, 12, 20, 0x8d2a4c8a);
396 OP (FH
, A
, B
, C
, D
, 5, 4, 0xfffa3942);
397 OP (FH
, D
, A
, B
, C
, 8, 11, 0x8771f681);
398 OP (FH
, C
, D
, A
, B
, 11, 16, 0x6d9d6122);
399 OP (FH
, B
, C
, D
, A
, 14, 23, 0xfde5380c);
400 OP (FH
, A
, B
, C
, D
, 1, 4, 0xa4beea44);
401 OP (FH
, D
, A
, B
, C
, 4, 11, 0x4bdecfa9);
402 OP (FH
, C
, D
, A
, B
, 7, 16, 0xf6bb4b60);
403 OP (FH
, B
, C
, D
, A
, 10, 23, 0xbebfbc70);
404 OP (FH
, A
, B
, C
, D
, 13, 4, 0x289b7ec6);
405 OP (FH
, D
, A
, B
, C
, 0, 11, 0xeaa127fa);
406 OP (FH
, C
, D
, A
, B
, 3, 16, 0xd4ef3085);
407 OP (FH
, B
, C
, D
, A
, 6, 23, 0x04881d05);
408 OP (FH
, A
, B
, C
, D
, 9, 4, 0xd9d4d039);
409 OP (FH
, D
, A
, B
, C
, 12, 11, 0xe6db99e5);
410 OP (FH
, C
, D
, A
, B
, 15, 16, 0x1fa27cf8);
411 OP (FH
, B
, C
, D
, A
, 2, 23, 0xc4ac5665);
414 OP (FI
, A
, B
, C
, D
, 0, 6, 0xf4292244);
415 OP (FI
, D
, A
, B
, C
, 7, 10, 0x432aff97);
416 OP (FI
, C
, D
, A
, B
, 14, 15, 0xab9423a7);
417 OP (FI
, B
, C
, D
, A
, 5, 21, 0xfc93a039);
418 OP (FI
, A
, B
, C
, D
, 12, 6, 0x655b59c3);
419 OP (FI
, D
, A
, B
, C
, 3, 10, 0x8f0ccc92);
420 OP (FI
, C
, D
, A
, B
, 10, 15, 0xffeff47d);
421 OP (FI
, B
, C
, D
, A
, 1, 21, 0x85845dd1);
422 OP (FI
, A
, B
, C
, D
, 8, 6, 0x6fa87e4f);
423 OP (FI
, D
, A
, B
, C
, 15, 10, 0xfe2ce6e0);
424 OP (FI
, C
, D
, A
, B
, 6, 15, 0xa3014314);
425 OP (FI
, B
, C
, D
, A
, 13, 21, 0x4e0811a1);
426 OP (FI
, A
, B
, C
, D
, 4, 6, 0xf7537e82);
427 OP (FI
, D
, A
, B
, C
, 11, 10, 0xbd3af235);
428 OP (FI
, C
, D
, A
, B
, 2, 15, 0x2ad7d2bb);
429 OP (FI
, B
, C
, D
, A
, 9, 21, 0xeb86d391);
431 /* Add the starting values of the context. */
438 /* Put checksum in context given as argument. */