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 3 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. If not, see
18 <http://www.gnu.org/licenses/>. */
20 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
26 /* modified for Wget: depend on C89 */
35 # if __BYTE_ORDER == __BIG_ENDIAN
36 # define WORDS_BIGENDIAN 1
40 #ifdef WORDS_BIGENDIAN
42 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
48 /* This array contains the bytes used to pad the buffer to the next
49 64-byte boundary. (RFC 1321, 3.1: Step 1) */
50 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
53 /* Initialize structure containing state of computation.
54 (RFC 1321, 3.3: Step 3) */
56 md5_init_ctx (struct md5_ctx *ctx)
63 ctx->total[0] = ctx->total[1] = 0;
67 /* Put result from CTX in first 16 bytes following RESBUF. The result
68 must be in little endian byte order.
70 IMPORTANT: On some systems it is required that RESBUF is correctly
71 aligned for a 32 bits value. */
73 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
75 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
76 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
77 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
78 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
83 /* Process the remaining bytes in the internal buffer and the usual
84 prolog according to the standard and write the result to RESBUF.
86 IMPORTANT: On some systems it is required that RESBUF is correctly
87 aligned for a 32 bits value. */
89 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
91 /* Take yet unprocessed bytes into account. */
92 md5_uint32 bytes = ctx->buflen;
95 /* Now count remaining bytes. */
96 ctx->total[0] += bytes;
97 if (ctx->total[0] < bytes)
100 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
101 memcpy (&ctx->buffer[bytes], fillbuf, pad);
103 /* Put the 64-bit file length in *bits* at the end of the buffer. */
104 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
105 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
106 (ctx->total[0] >> 29));
108 /* Process last bytes. */
109 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
111 return md5_read_ctx (ctx, resbuf);
116 /* Compute MD5 message digest for bytes read from STREAM. The
117 resulting message digest number will be written into the 16 bytes
118 beginning at RESBLOCK. */
120 md5_stream (FILE *stream, void *resblock)
122 /* Important: BLOCKSIZE must be a multiple of 64. */
123 #define BLOCKSIZE 4096
125 char buffer[BLOCKSIZE + 72];
128 /* Initialize the computation context. */
131 /* Iterate over full file contents. */
134 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
135 computation function processes the whole buffer so that with the
136 next round of the loop another block can be read. */
140 /* Read block. Take care for partial reads. */
143 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
147 while (sum < BLOCKSIZE && n != 0);
148 if (n == 0 && ferror (stream))
151 /* If end of file is reached, end the loop. */
155 /* Process buffer with BLOCKSIZE bytes. Note that
158 md5_process_block (buffer, BLOCKSIZE, &ctx);
161 /* Add the last bytes if necessary. */
163 md5_process_bytes (buffer, sum, &ctx);
165 /* Construct result in desired memory. */
166 md5_finish_ctx (&ctx, resblock);
170 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
171 result is always in little endian byte order, so that a byte-wise
172 output yields to the wanted ASCII representation of the message
175 md5_buffer (const char *buffer, size_t len, void *resblock)
179 /* Initialize the computation context. */
182 /* Process whole buffer but last len % 64 bytes. */
183 md5_process_bytes (buffer, len, &ctx);
185 /* Put result in desired memory area. */
186 return md5_finish_ctx (&ctx, resblock);
192 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
194 /* When we already have some bits in our internal buffer concatenate
195 both inputs first. */
196 if (ctx->buflen != 0)
198 size_t left_over = ctx->buflen;
199 size_t add = 128 - left_over > len ? len : 128 - left_over;
201 memcpy (&ctx->buffer[left_over], buffer, add);
204 if (left_over + add > 64)
206 md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
207 /* The regions in the following copy operation cannot overlap. */
208 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
209 (left_over + add) & 63);
210 ctx->buflen = (left_over + add) & 63;
213 buffer = (const char *) buffer + add;
217 /* Process available complete blocks. */
220 md5_process_block (buffer, len & ~63, ctx);
221 buffer = (const char *) buffer + (len & ~63);
225 /* Move remaining bytes in internal buffer. */
228 memcpy (ctx->buffer, buffer, len);
234 /* These are the four functions used in the four steps of the MD5 algorithm
235 and defined in the RFC 1321. The first function is a little bit optimized
236 (as found in Colin Plumbs public domain implementation). */
237 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
238 #define FF(b, c, d) (d ^ (b & (c ^ d)))
239 #define FG(b, c, d) FF (d, b, c)
240 #define FH(b, c, d) (b ^ c ^ d)
241 #define FI(b, c, d) (c ^ (b | ~d))
243 /* Process LEN bytes of BUFFER, accumulating context into CTX.
244 It is assumed that LEN % 64 == 0. */
247 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
249 md5_uint32 correct_words[16];
250 const md5_uint32 *words = (md5_uint32 *)buffer;
251 size_t nwords = len / sizeof (md5_uint32);
252 const md5_uint32 *endp = words + nwords;
253 md5_uint32 A = ctx->A;
254 md5_uint32 B = ctx->B;
255 md5_uint32 C = ctx->C;
256 md5_uint32 D = ctx->D;
258 /* First increment the byte count. RFC 1321 specifies the possible
259 length of the file up to 2^64 bits. Here we only compute the
260 number of bytes. Do a double word increment. */
261 ctx->total[0] += len;
262 if (ctx->total[0] < len)
265 /* Process all bytes in the buffer with 64 bytes in each round of
269 md5_uint32 *cwp = correct_words;
270 md5_uint32 A_save = A;
271 md5_uint32 B_save = B;
272 md5_uint32 C_save = C;
273 md5_uint32 D_save = D;
275 /* First round: using the given function, the context and a constant
276 the next context is computed. Because the algorithms processing
277 unit is a 32-bit word and it is determined to work on words in
278 little endian byte order we perhaps have to change the byte order
279 before the computation. To reduce the work for the next steps
280 we store the swapped words in the array CORRECT_WORDS. */
282 #define OP(a, b, c, d, s, T) \
285 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
292 /* It is unfortunate that C does not provide an operator for
293 cyclic rotation. Hope the C compiler is smart enough. */
294 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
296 /* Before we start, one word to the strange constants.
297 They are defined in RFC 1321 as
299 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
303 OP (A, B, C, D, 7, 0xd76aa478);
304 OP (D, A, B, C, 12, 0xe8c7b756);
305 OP (C, D, A, B, 17, 0x242070db);
306 OP (B, C, D, A, 22, 0xc1bdceee);
307 OP (A, B, C, D, 7, 0xf57c0faf);
308 OP (D, A, B, C, 12, 0x4787c62a);
309 OP (C, D, A, B, 17, 0xa8304613);
310 OP (B, C, D, A, 22, 0xfd469501);
311 OP (A, B, C, D, 7, 0x698098d8);
312 OP (D, A, B, C, 12, 0x8b44f7af);
313 OP (C, D, A, B, 17, 0xffff5bb1);
314 OP (B, C, D, A, 22, 0x895cd7be);
315 OP (A, B, C, D, 7, 0x6b901122);
316 OP (D, A, B, C, 12, 0xfd987193);
317 OP (C, D, A, B, 17, 0xa679438e);
318 OP (B, C, D, A, 22, 0x49b40821);
320 /* For the second to fourth round we have the possibly swapped words
321 in CORRECT_WORDS. Redefine the macro to take an additional first
322 argument specifying the function to use. */
324 #define OP(f, a, b, c, d, k, s, T) \
327 a += f (b, c, d) + correct_words[k] + T; \
334 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
335 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
336 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
337 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
338 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
339 OP (FG, D, A, B, C, 10, 9, 0x02441453);
340 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
341 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
342 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
343 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
344 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
345 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
346 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
347 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
348 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
349 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
352 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
353 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
354 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
355 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
356 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
357 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
358 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
359 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
360 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
361 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
362 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
363 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
364 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
365 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
366 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
367 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
370 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
371 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
372 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
373 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
374 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
375 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
376 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
377 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
378 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
379 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
380 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
381 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
382 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
383 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
384 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
385 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
387 /* Add the starting values of the context. */
394 /* Put checksum in context given as argument. */