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 This file is part of the GNU C library.
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. */
38 #if defined( __OpenBSD__ )
39 # include <machine/types.h>
40 # include <sys/endian.h>
41 #elif defined( __FreeBSD__ ) || defined( __NetBSD__ )
42 # include <sys/types.h>
43 # include <sys/endian.h>
44 #elif defined( BSD ) && ( BSD >= 199103 ) || defined(__APPLE__)
45 # include <machine/endian.h>
50 # if __BYTE_ORDER == __BIG_ENDIAN
51 # define WORDS_BIGENDIAN 1
52 # elif __BYTE_ORDER == __LITTLE_ENDIAN
53 # define WORDS_BIGENDIAN 1
55 # error __BYTE_ORDER is not set correctly
58 #if defined(WORDS_BIGENDIAN) || defined(_BIG_ENDIAN)
60 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
61 #elif defined(_LITTLE_ENDIAN)
64 # error Neither __BYTE_ORDER nor _LITTLE_ENDIAN is defined
68 /* This array contains the bytes used to pad the buffer to the next
69 64-byte boundary. (RFC 1321, 3.1: Step 1) */
70 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
73 /* Initialize structure containing state of computation.
74 (RFC 1321, 3.3: Step 3) */
76 md5_init_ctx (struct md5_ctx *ctx)
83 ctx->total[0] = ctx->total[1] = 0;
87 /* Put result from CTX in first 16 bytes following RESBUF. The result
88 must be in little endian byte order.
90 IMPORTANT: On some systems it is required that RESBUF is correctly
91 aligned for a 32 bits value. */
93 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
95 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
96 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
97 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
98 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
103 /* Process the remaining bytes in the internal buffer and the usual
104 prolog according to the standard and write the result to RESBUF.
106 IMPORTANT: On some systems it is required that RESBUF is correctly
107 aligned for a 32 bits value. */
109 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
111 /* Take yet unprocessed bytes into account. */
112 md5_uint32 bytes = ctx->buflen;
115 /* Now count remaining bytes. */
116 ctx->total[0] += bytes;
117 if (ctx->total[0] < bytes)
120 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
121 memcpy (&ctx->buffer[bytes], fillbuf, pad);
123 /* Put the 64-bit file length in *bits* at the end of the buffer. */
124 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
125 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
126 (ctx->total[0] >> 29));
128 /* Process last bytes. */
129 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
131 return md5_read_ctx (ctx, resbuf);
134 /* Compute MD5 message digest for bytes read from STREAM. The
135 resulting message digest number will be written into the 16 bytes
136 beginning at RESBLOCK. */
138 md5_stream (FILE *stream, void *resblock)
140 /* Important: BLOCKSIZE must be a multiple of 64. */
141 #define BLOCKSIZE 4096
143 char buffer[BLOCKSIZE + 72];
146 /* Initialize the computation context. */
149 /* Iterate over full file contents. */
152 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
153 computation function processes the whole buffer so that with the
154 next round of the loop another block can be read. */
158 /* Read block. Take care for partial reads. */
161 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
165 while (sum < BLOCKSIZE && n != 0);
166 if (n == 0 && ferror (stream))
169 /* If end of file is reached, end the loop. */
173 /* Process buffer with BLOCKSIZE bytes. Note that
176 md5_process_block (buffer, BLOCKSIZE, &ctx);
179 /* Add the last bytes if necessary. */
181 md5_process_bytes (buffer, sum, &ctx);
183 /* Construct result in desired memory. */
184 md5_finish_ctx (&ctx, resblock);
188 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
189 result is always in little endian byte order, so that a byte-wise
190 output yields to the wanted ASCII representation of the message
193 md5_buffer (const char *buffer, size_t len, void *resblock)
197 /* Initialize the computation context. */
200 /* Process whole buffer but last len % 64 bytes. */
201 md5_process_bytes (buffer, len, &ctx);
203 /* Put result in desired memory area. */
204 return md5_finish_ctx (&ctx, resblock);
209 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
211 /* When we already have some bits in our internal buffer concatenate
212 both inputs first. */
213 if (ctx->buflen != 0)
215 size_t left_over = ctx->buflen;
216 size_t add = 128 - left_over > len ? len : 128 - left_over;
218 memcpy (&ctx->buffer[left_over], buffer, add);
221 if (left_over + add > 64)
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;
230 buffer = (const char *) buffer + add;
234 /* Process available complete blocks. */
237 md5_process_block (buffer, len & ~63, ctx);
238 buffer = (const char *) buffer + (len & ~63);
242 /* Move remaining bytes in internal buffer. */
245 memcpy (ctx->buffer, buffer, len);
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))
260 /* Process LEN bytes of BUFFER, accumulating context into CTX.
261 It is assumed that LEN % 64 == 0. */
264 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
266 md5_uint32 correct_words[16];
267 const md5_uint32 *words = buffer;
268 size_t nwords = len / sizeof (md5_uint32);
269 const md5_uint32 *endp = words + nwords;
270 md5_uint32 A = ctx->A;
271 md5_uint32 B = ctx->B;
272 md5_uint32 C = ctx->C;
273 md5_uint32 D = ctx->D;
275 /* First increment the byte count. RFC 1321 specifies the possible
276 length of the file up to 2^64 bits. Here we only compute the
277 number of bytes. Do a double word increment. */
278 ctx->total[0] += len;
279 if (ctx->total[0] < len)
282 /* Process all bytes in the buffer with 64 bytes in each round of
286 md5_uint32 *cwp = correct_words;
287 md5_uint32 A_save = A;
288 md5_uint32 B_save = B;
289 md5_uint32 C_save = C;
290 md5_uint32 D_save = D;
292 /* First round: using the given function, the context and a constant
293 the next context is computed. Because the algorithms processing
294 unit is a 32-bit word and it is determined to work on words in
295 little endian byte order we perhaps have to change the byte order
296 before the computation. To reduce the work for the next steps
297 we store the swapped words in the array CORRECT_WORDS. */
299 #define OP(a, b, c, d, s, T) \
302 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
309 /* It is unfortunate that C does not provide an operator for
310 cyclic rotation. Hope the C compiler is smart enough. */
311 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
313 /* Before we start, one word to the strange constants.
314 They are defined in RFC 1321 as
316 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
320 OP (A, B, C, D, 7, 0xd76aa478);
321 OP (D, A, B, C, 12, 0xe8c7b756);
322 OP (C, D, A, B, 17, 0x242070db);
323 OP (B, C, D, A, 22, 0xc1bdceee);
324 OP (A, B, C, D, 7, 0xf57c0faf);
325 OP (D, A, B, C, 12, 0x4787c62a);
326 OP (C, D, A, B, 17, 0xa8304613);
327 OP (B, C, D, A, 22, 0xfd469501);
328 OP (A, B, C, D, 7, 0x698098d8);
329 OP (D, A, B, C, 12, 0x8b44f7af);
330 OP (C, D, A, B, 17, 0xffff5bb1);
331 OP (B, C, D, A, 22, 0x895cd7be);
332 OP (A, B, C, D, 7, 0x6b901122);
333 OP (D, A, B, C, 12, 0xfd987193);
334 OP (C, D, A, B, 17, 0xa679438e);
335 OP (B, C, D, A, 22, 0x49b40821);
337 /* For the second to fourth round we have the possibly swapped words
338 in CORRECT_WORDS. Redefine the macro to take an additional first
339 argument specifying the function to use. */
341 #define OP(f, a, b, c, d, k, s, T) \
344 a += f (b, c, d) + correct_words[k] + T; \
351 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
352 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
353 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
354 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
355 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
356 OP (FG, D, A, B, C, 10, 9, 0x02441453);
357 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
358 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
359 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
360 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
361 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
362 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
363 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
364 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
365 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
366 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
369 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
370 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
371 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
372 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
373 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
374 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
375 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
376 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
377 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
378 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
379 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
380 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
381 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
382 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
383 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
384 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
387 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
388 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
389 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
390 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
391 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
392 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
393 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
394 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
395 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
396 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
397 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
398 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
399 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
400 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
401 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
402 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
404 /* Add the starting values of the context. */
411 /* Put checksum in context given as argument. */