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, 2001, 2003 Free Software Foundation, Inc.
4 NOTE: The canonical source of this file is maintained with the GNU C
5 Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu.
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software Foundation,
19 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
27 #include <sys/types.h>
33 #include "unlocked-io.h"
37 # if __BYTE_ORDER == __BIG_ENDIAN
38 # define WORDS_BIGENDIAN 1
40 /* We need to keep the namespace clean so define the MD5 function
41 protected using leading __ . */
42 # define md5_init_ctx __md5_init_ctx
43 # define md5_process_block __md5_process_block
44 # define md5_process_bytes __md5_process_bytes
45 # define md5_finish_ctx __md5_finish_ctx
46 # define md5_read_ctx __md5_read_ctx
47 # define md5_stream __md5_stream
48 # define md5_buffer __md5_buffer
51 #ifdef WORDS_BIGENDIAN
53 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
58 #define BLOCKSIZE 4096
59 /* Ensure that BLOCKSIZE is a multiple of 64. */
60 #if BLOCKSIZE % 64 != 0
61 /* FIXME-someday (soon?): use #error instead of this kludge. */
65 /* This array contains the bytes used to pad the buffer to the next
66 64-byte boundary. (RFC 1321, 3.1: Step 1) */
67 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
70 /* Initialize structure containing state of computation.
71 (RFC 1321, 3.3: Step 3) */
81 ctx->total[0] = ctx->total[1] = 0;
85 /* Put result from CTX in first 16 bytes following RESBUF. The result
86 must be in little endian byte order.
88 IMPORTANT: On some systems it is required that RESBUF is correctly
89 aligned for a 32 bits value. */
91 md5_read_ctx (ctx, resbuf)
92 const struct md5_ctx *ctx;
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 (ctx, resbuf)
113 /* Take yet unprocessed bytes into account. */
114 md5_uint32 bytes = ctx->buflen;
117 /* Now count remaining bytes. */
118 ctx->total[0] += bytes;
119 if (ctx->total[0] < bytes)
122 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
123 memcpy (&ctx->buffer[bytes], fillbuf, pad);
125 /* Put the 64-bit file length in *bits* at the end of the buffer. */
126 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
127 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
128 (ctx->total[0] >> 29));
130 /* Process last bytes. */
131 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
133 return md5_read_ctx (ctx, resbuf);
136 /* Compute MD5 message digest for bytes read from STREAM. The
137 resulting message digest number will be written into the 16 bytes
138 beginning at RESBLOCK. */
140 md5_stream (stream, resblock)
145 char buffer[BLOCKSIZE + 72];
148 /* Initialize the computation context. */
151 /* Iterate over full file contents. */
154 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
155 computation function processes the whole buffer so that with the
156 next round of the loop another block can be read. */
160 /* Read block. Take care for partial reads. */
163 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
167 if (sum == BLOCKSIZE)
172 /* Check for the error flag IFF N == 0, so that we don't
173 exit the loop after a partial read due to e.g., EAGAIN
177 goto process_partial_block;
180 /* We've read at least one byte, so ignore errors. But always
181 check for EOF, since feof may be true even though N > 0.
182 Otherwise, we could end up calling fread after EOF. */
184 goto process_partial_block;
187 /* Process buffer with BLOCKSIZE bytes. Note that
190 md5_process_block (buffer, BLOCKSIZE, &ctx);
193 process_partial_block:;
195 /* Process any remaining bytes. */
197 md5_process_bytes (buffer, sum, &ctx);
199 /* Construct result in desired memory. */
200 md5_finish_ctx (&ctx, resblock);
204 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
205 result is always in little endian byte order, so that a byte-wise
206 output yields to the wanted ASCII representation of the message
209 md5_buffer (buffer, len, resblock)
216 /* Initialize the computation context. */
219 /* Process whole buffer but last len % 64 bytes. */
220 md5_process_bytes (buffer, len, &ctx);
222 /* Put result in desired memory area. */
223 return md5_finish_ctx (&ctx, resblock);
228 md5_process_bytes (buffer, len, ctx)
233 /* When we already have some bits in our internal buffer concatenate
234 both inputs first. */
235 if (ctx->buflen != 0)
237 size_t left_over = ctx->buflen;
238 size_t add = 128 - left_over > len ? len : 128 - left_over;
240 memcpy (&ctx->buffer[left_over], buffer, add);
243 if (ctx->buflen > 64)
245 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
248 /* The regions in the following copy operation cannot overlap. */
249 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
253 buffer = (const char *) buffer + add;
257 /* Process available complete blocks. */
260 #if !_STRING_ARCH_unaligned
261 /* To check alignment gcc has an appropriate operator. Other
264 # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0)
266 # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0)
268 if (UNALIGNED_P (buffer))
271 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
272 buffer = (const char *) buffer + 64;
278 md5_process_block (buffer, len & ~63, ctx);
279 buffer = (const char *) buffer + (len & ~63);
284 /* Move remaining bytes in internal buffer. */
287 size_t left_over = ctx->buflen;
289 memcpy (&ctx->buffer[left_over], buffer, len);
293 md5_process_block (ctx->buffer, 64, ctx);
295 memcpy (ctx->buffer, &ctx->buffer[64], left_over);
297 ctx->buflen = left_over;
302 /* These are the four functions used in the four steps of the MD5 algorithm
303 and defined in the RFC 1321. The first function is a little bit optimized
304 (as found in Colin Plumbs public domain implementation). */
305 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
306 #define FF(b, c, d) (d ^ (b & (c ^ d)))
307 #define FG(b, c, d) FF (d, b, c)
308 #define FH(b, c, d) (b ^ c ^ d)
309 #define FI(b, c, d) (c ^ (b | ~d))
311 /* Process LEN bytes of BUFFER, accumulating context into CTX.
312 It is assumed that LEN % 64 == 0. */
315 md5_process_block (buffer, len, ctx)
320 md5_uint32 correct_words[16];
321 const md5_uint32 *words = buffer;
322 size_t nwords = len / sizeof (md5_uint32);
323 const md5_uint32 *endp = words + nwords;
324 md5_uint32 A = ctx->A;
325 md5_uint32 B = ctx->B;
326 md5_uint32 C = ctx->C;
327 md5_uint32 D = ctx->D;
329 /* First increment the byte count. RFC 1321 specifies the possible
330 length of the file up to 2^64 bits. Here we only compute the
331 number of bytes. Do a double word increment. */
332 ctx->total[0] += len;
333 if (ctx->total[0] < len)
336 /* Process all bytes in the buffer with 64 bytes in each round of
340 md5_uint32 *cwp = correct_words;
341 md5_uint32 A_save = A;
342 md5_uint32 B_save = B;
343 md5_uint32 C_save = C;
344 md5_uint32 D_save = D;
346 /* First round: using the given function, the context and a constant
347 the next context is computed. Because the algorithms processing
348 unit is a 32-bit word and it is determined to work on words in
349 little endian byte order we perhaps have to change the byte order
350 before the computation. To reduce the work for the next steps
351 we store the swapped words in the array CORRECT_WORDS. */
353 #define OP(a, b, c, d, s, T) \
356 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
363 /* Before we start, one word to the strange constants.
364 They are defined in RFC 1321 as
366 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64, or
367 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
371 OP (A, B, C, D, 7, 0xd76aa478);
372 OP (D, A, B, C, 12, 0xe8c7b756);
373 OP (C, D, A, B, 17, 0x242070db);
374 OP (B, C, D, A, 22, 0xc1bdceee);
375 OP (A, B, C, D, 7, 0xf57c0faf);
376 OP (D, A, B, C, 12, 0x4787c62a);
377 OP (C, D, A, B, 17, 0xa8304613);
378 OP (B, C, D, A, 22, 0xfd469501);
379 OP (A, B, C, D, 7, 0x698098d8);
380 OP (D, A, B, C, 12, 0x8b44f7af);
381 OP (C, D, A, B, 17, 0xffff5bb1);
382 OP (B, C, D, A, 22, 0x895cd7be);
383 OP (A, B, C, D, 7, 0x6b901122);
384 OP (D, A, B, C, 12, 0xfd987193);
385 OP (C, D, A, B, 17, 0xa679438e);
386 OP (B, C, D, A, 22, 0x49b40821);
388 /* For the second to fourth round we have the possibly swapped words
389 in CORRECT_WORDS. Redefine the macro to take an additional first
390 argument specifying the function to use. */
392 #define OP(f, a, b, c, d, k, s, T) \
395 a += f (b, c, d) + correct_words[k] + T; \
402 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
403 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
404 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
405 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
406 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
407 OP (FG, D, A, B, C, 10, 9, 0x02441453);
408 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
409 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
410 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
411 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
412 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
413 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
414 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
415 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
416 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
417 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
420 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
421 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
422 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
423 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
424 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
425 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
426 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
427 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
428 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
429 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
430 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
431 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
432 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
433 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
434 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
435 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
438 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
439 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
440 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
441 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
442 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
443 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
444 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
445 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
446 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
447 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
448 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
449 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
450 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
451 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
452 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
453 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
455 /* Add the starting values of the context. */
462 /* Put checksum in context given as argument. */