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) 1995,1996,1997,1999,2000,2001,2005,2006,2008
4 Free Software Foundation, Inc.
5 This file is part of the GNU C Library.
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
30 #include <sys/types.h>
33 #include "unlocked-io.h"
38 #if __BYTE_ORDER == __BIG_ENDIAN
39 #define WORDS_BIGENDIAN 1
41 /* We need to keep the namespace clean so define the MD5 function
42 protected using leading __ . */
43 #define md5_init_ctx __md5_init_ctx
44 #define md5_process_block __md5_process_block
45 #define md5_process_bytes __md5_process_bytes
46 #define md5_finish_ctx __md5_finish_ctx
47 #define md5_read_ctx __md5_read_ctx
48 #define md5_stream __md5_stream
49 #define md5_buffer __md5_buffer
52 #ifdef WORDS_BIGENDIAN
54 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
59 #define BLOCKSIZE 4096
60 #if BLOCKSIZE % 64 != 0
61 #error "invalid BLOCKSIZE"
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, ... */ };
68 /* Initialize structure containing state of computation.
69 (RFC 1321, 3.3: Step 3) */
70 void md5_init_ctx(struct md5_ctx *ctx)
77 ctx->total[0] = ctx->total[1] = 0;
81 /* Copy the 4 byte value from v into the memory location pointed to by *cp,
82 If your architecture allows unaligned access this is equivalent to
83 * (uint32_t *) cp = v */
84 static inline void set_uint32(char *cp, uint32_t v)
86 memcpy(cp, &v, sizeof v);
89 /* Put result from CTX in first 16 bytes following RESBUF. The result
90 must be in little endian byte order. */
91 void *md5_read_ctx(const struct md5_ctx *ctx, void *resbuf)
94 set_uint32(r + 0 * sizeof ctx->A, SWAP(ctx->A));
95 set_uint32(r + 1 * sizeof ctx->B, SWAP(ctx->B));
96 set_uint32(r + 2 * sizeof ctx->C, SWAP(ctx->C));
97 set_uint32(r + 3 * sizeof ctx->D, 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. */
104 void *md5_finish_ctx(struct md5_ctx *ctx, void *resbuf)
106 /* Take yet unprocessed bytes into account. */
107 uint32_t bytes = ctx->buflen;
108 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
110 /* Now count remaining bytes. */
111 ctx->total[0] += bytes;
112 if (ctx->total[0] < bytes)
115 /* Put the 64-bit file length in *bits* at the end of the buffer. */
116 ctx->buffer[size - 2] = SWAP(ctx->total[0] << 3);
117 ctx->buffer[size - 1] =
118 SWAP((ctx->total[1] << 3) | (ctx->total[0] >> 29));
120 memcpy(&((char *)ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
122 /* Process last bytes. */
123 md5_process_block(ctx->buffer, size * 4, ctx);
125 return md5_read_ctx(ctx, resbuf);
128 /* Compute MD5 message digest for bytes read from STREAM. The
129 resulting message digest number will be written into the 16 bytes
130 beginning at RESBLOCK. */
131 int md5_stream(FILE * stream, void *resblock)
134 char buffer[BLOCKSIZE + 72];
137 /* Initialize the computation context. */
140 /* Iterate over full file contents. */
142 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
143 computation function processes the whole buffer so that with the
144 next round of the loop another block can be read. */
148 /* Read block. Take care for partial reads. */
150 n = fread(buffer + sum, 1, BLOCKSIZE - sum, stream);
154 if (sum == BLOCKSIZE)
158 /* Check for the error flag IFF N == 0, so that we don't
159 exit the loop after a partial read due to e.g., EAGAIN
163 goto process_partial_block;
166 /* We've read at least one byte, so ignore errors. But always
167 check for EOF, since feof may be true even though N > 0.
168 Otherwise, we could end up calling fread after EOF. */
170 goto process_partial_block;
173 /* Process buffer with BLOCKSIZE bytes. Note that
176 md5_process_block(buffer, BLOCKSIZE, &ctx);
179 process_partial_block:
181 /* Process any remaining bytes. */
183 md5_process_bytes(buffer, sum, &ctx);
185 /* Construct result in desired memory. */
186 md5_finish_ctx(&ctx, resblock);
190 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
191 result is always in little endian byte order, so that a byte-wise
192 output yields to the wanted ASCII representation of the message
194 void *md5_buffer(const char *buffer, size_t len, void *resblock)
198 /* Initialize the computation context. */
201 /* Process whole buffer but last len % 64 bytes. */
202 md5_process_bytes(buffer, len, &ctx);
204 /* Put result in desired memory area. */
205 return md5_finish_ctx(&ctx, resblock);
208 void md5_process_bytes(const void *buffer, size_t len, struct md5_ctx *ctx)
210 /* When we already have some bits in our internal buffer concatenate
211 both inputs first. */
212 if (ctx->buflen != 0) {
213 size_t left_over = ctx->buflen;
214 size_t add = 128 - left_over > len ? len : 128 - left_over;
216 memcpy(&((char *)ctx->buffer)[left_over], buffer, add);
219 if (ctx->buflen > 64) {
220 md5_process_block(ctx->buffer, ctx->buflen & ~63, ctx);
223 /* The regions in the following copy operation cannot overlap. */
225 &((char *)ctx->buffer)[(left_over + add) & ~63],
229 buffer = (const char *)buffer + add;
233 /* Process available complete blocks. */
235 #if !_STRING_ARCH_unaligned
236 #define alignof(type) offsetof (struct { char c; type x; }, x)
237 #define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0)
238 if (UNALIGNED_P(buffer))
240 md5_process_block(memcpy
241 (ctx->buffer, buffer, 64), 64,
243 buffer = (const char *)buffer + 64;
248 md5_process_block(buffer, len & ~63, ctx);
249 buffer = (const char *)buffer + (len & ~63);
254 /* Move remaining bytes in internal buffer. */
256 size_t left_over = ctx->buflen;
258 memcpy(&((char *)ctx->buffer)[left_over], buffer, len);
260 if (left_over >= 64) {
261 md5_process_block(ctx->buffer, 64, ctx);
263 memcpy(ctx->buffer, &ctx->buffer[16], left_over);
265 ctx->buflen = left_over;
269 /* These are the four functions used in the four steps of the MD5 algorithm
270 and defined in the RFC 1321. The first function is a little bit optimized
271 (as found in Colin Plumbs public domain implementation). */
272 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
273 #define FF(b, c, d) (d ^ (b & (c ^ d)))
274 #define FG(b, c, d) FF (d, b, c)
275 #define FH(b, c, d) (b ^ c ^ d)
276 #define FI(b, c, d) (c ^ (b | ~d))
278 /* Process LEN bytes of BUFFER, accumulating context into CTX.
279 It is assumed that LEN % 64 == 0. */
281 void md5_process_block(const void *buffer, size_t len, struct md5_ctx *ctx)
283 uint32_t correct_words[16];
284 const uint32_t *words = buffer;
285 size_t nwords = len / sizeof(uint32_t);
286 const uint32_t *endp = words + nwords;
292 /* First increment the byte count. RFC 1321 specifies the possible
293 length of the file up to 2^64 bits. Here we only compute the
294 number of bytes. Do a double word increment. */
295 ctx->total[0] += len;
296 if (ctx->total[0] < len)
299 /* Process all bytes in the buffer with 64 bytes in each round of
301 while (words < endp) {
302 uint32_t *cwp = correct_words;
308 /* First round: using the given function, the context and a constant
309 the next context is computed. Because the algorithms processing
310 unit is a 32-bit word and it is determined to work on words in
311 little endian byte order we perhaps have to change the byte order
312 before the computation. To reduce the work for the next steps
313 we store the swapped words in the array CORRECT_WORDS. */
315 #define OP(a, b, c, d, s, T) \
318 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
325 /* It is unfortunate that C does not provide an operator for
326 cyclic rotation. Hope the C compiler is smart enough. */
327 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
329 /* Before we start, one word to the strange constants.
330 They are defined in RFC 1321 as
332 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
334 Here is an equivalent invocation using Perl:
336 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
340 OP(A, B, C, D, 7, 0xd76aa478);
341 OP(D, A, B, C, 12, 0xe8c7b756);
342 OP(C, D, A, B, 17, 0x242070db);
343 OP(B, C, D, A, 22, 0xc1bdceee);
344 OP(A, B, C, D, 7, 0xf57c0faf);
345 OP(D, A, B, C, 12, 0x4787c62a);
346 OP(C, D, A, B, 17, 0xa8304613);
347 OP(B, C, D, A, 22, 0xfd469501);
348 OP(A, B, C, D, 7, 0x698098d8);
349 OP(D, A, B, C, 12, 0x8b44f7af);
350 OP(C, D, A, B, 17, 0xffff5bb1);
351 OP(B, C, D, A, 22, 0x895cd7be);
352 OP(A, B, C, D, 7, 0x6b901122);
353 OP(D, A, B, C, 12, 0xfd987193);
354 OP(C, D, A, B, 17, 0xa679438e);
355 OP(B, C, D, A, 22, 0x49b40821);
357 /* For the second to fourth round we have the possibly swapped words
358 in CORRECT_WORDS. Redefine the macro to take an additional first
359 argument specifying the function to use. */
361 #define OP(f, a, b, c, d, k, s, T) \
364 a += f (b, c, d) + correct_words[k] + T; \
371 OP(FG, A, B, C, D, 1, 5, 0xf61e2562);
372 OP(FG, D, A, B, C, 6, 9, 0xc040b340);
373 OP(FG, C, D, A, B, 11, 14, 0x265e5a51);
374 OP(FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
375 OP(FG, A, B, C, D, 5, 5, 0xd62f105d);
376 OP(FG, D, A, B, C, 10, 9, 0x02441453);
377 OP(FG, C, D, A, B, 15, 14, 0xd8a1e681);
378 OP(FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
379 OP(FG, A, B, C, D, 9, 5, 0x21e1cde6);
380 OP(FG, D, A, B, C, 14, 9, 0xc33707d6);
381 OP(FG, C, D, A, B, 3, 14, 0xf4d50d87);
382 OP(FG, B, C, D, A, 8, 20, 0x455a14ed);
383 OP(FG, A, B, C, D, 13, 5, 0xa9e3e905);
384 OP(FG, D, A, B, C, 2, 9, 0xfcefa3f8);
385 OP(FG, C, D, A, B, 7, 14, 0x676f02d9);
386 OP(FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
389 OP(FH, A, B, C, D, 5, 4, 0xfffa3942);
390 OP(FH, D, A, B, C, 8, 11, 0x8771f681);
391 OP(FH, C, D, A, B, 11, 16, 0x6d9d6122);
392 OP(FH, B, C, D, A, 14, 23, 0xfde5380c);
393 OP(FH, A, B, C, D, 1, 4, 0xa4beea44);
394 OP(FH, D, A, B, C, 4, 11, 0x4bdecfa9);
395 OP(FH, C, D, A, B, 7, 16, 0xf6bb4b60);
396 OP(FH, B, C, D, A, 10, 23, 0xbebfbc70);
397 OP(FH, A, B, C, D, 13, 4, 0x289b7ec6);
398 OP(FH, D, A, B, C, 0, 11, 0xeaa127fa);
399 OP(FH, C, D, A, B, 3, 16, 0xd4ef3085);
400 OP(FH, B, C, D, A, 6, 23, 0x04881d05);
401 OP(FH, A, B, C, D, 9, 4, 0xd9d4d039);
402 OP(FH, D, A, B, C, 12, 11, 0xe6db99e5);
403 OP(FH, C, D, A, B, 15, 16, 0x1fa27cf8);
404 OP(FH, B, C, D, A, 2, 23, 0xc4ac5665);
407 OP(FI, A, B, C, D, 0, 6, 0xf4292244);
408 OP(FI, D, A, B, C, 7, 10, 0x432aff97);
409 OP(FI, C, D, A, B, 14, 15, 0xab9423a7);
410 OP(FI, B, C, D, A, 5, 21, 0xfc93a039);
411 OP(FI, A, B, C, D, 12, 6, 0x655b59c3);
412 OP(FI, D, A, B, C, 3, 10, 0x8f0ccc92);
413 OP(FI, C, D, A, B, 10, 15, 0xffeff47d);
414 OP(FI, B, C, D, A, 1, 21, 0x85845dd1);
415 OP(FI, A, B, C, D, 8, 6, 0x6fa87e4f);
416 OP(FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
417 OP(FI, C, D, A, B, 6, 15, 0xa3014314);
418 OP(FI, B, C, D, A, 13, 21, 0x4e0811a1);
419 OP(FI, A, B, C, D, 4, 6, 0xf7537e82);
420 OP(FI, D, A, B, C, 11, 10, 0xbd3af235);
421 OP(FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
422 OP(FI, B, C, D, A, 9, 21, 0xeb86d391);
424 /* Add the starting values of the context. */
431 /* Put checksum in context given as argument. */