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) 1995-2011, 2015 Red Hat, Inc.
4 This file is part of elfutils.
5 Written by Ulrich Drepper <drepper@redhat.com>, 1995.
7 This file is free software; you can redistribute it and/or modify
8 it under the terms of either
10 * the GNU Lesser General Public License as published by the Free
11 Software Foundation; either version 3 of the License, or (at
12 your option) any later version
16 * the GNU General Public License as published by the Free
17 Software Foundation; either version 2 of the License, or (at
18 your option) any later version
20 or both in parallel, as here.
22 elfutils is distributed in the hope that it will be useful, but
23 WITHOUT ANY WARRANTY; without even the implied warranty of
24 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
25 General Public License for more details.
27 You should have received copies of the GNU General Public License and
28 the GNU Lesser General Public License along with this program. If
29 not, see <http://www.gnu.org/licenses/>. */
37 #include <sys/types.h>
42 #define SWAP(n) LE32 (n)
44 /* This array contains the bytes used to pad the buffer to the next
45 64-byte boundary. (RFC 1321, 3.1: Step 1) */
46 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
49 /* Initialize structure containing state of computation.
50 (RFC 1321, 3.3: Step 3) */
52 md5_init_ctx (struct md5_ctx *ctx)
59 ctx->total[0] = ctx->total[1] = 0;
63 /* Put result from CTX in first 16 bytes following RESBUF. The result
64 must be in little endian byte order.
66 IMPORTANT: On some systems it is required that RESBUF is correctly
67 aligned for a 32 bits value. */
69 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
71 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
72 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
73 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
74 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
80 le64_copy (char *dest, uint64_t x)
82 for (size_t i = 0; i < 8; ++i)
84 dest[i] = (uint8_t) x;
89 /* Process the remaining bytes in the internal buffer and the usual
90 prolog according to the standard and write the result to RESBUF.
92 IMPORTANT: On some systems it is required that RESBUF is correctly
93 aligned for a 32 bits value. */
95 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
97 /* Take yet unprocessed bytes into account. */
98 md5_uint32 bytes = ctx->buflen;
101 /* Now count remaining bytes. */
102 ctx->total[0] += bytes;
103 if (ctx->total[0] < bytes)
106 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
107 memcpy (&ctx->buffer[bytes], fillbuf, pad);
109 /* Put the 64-bit file length in *bits* at the end of the buffer. */
110 const uint64_t bit_length = ((ctx->total[0] << 3)
111 + ((uint64_t) ((ctx->total[1] << 3) |
112 (ctx->total[0] >> 29)) << 32));
113 le64_copy (&ctx->buffer[bytes + pad], bit_length);
115 /* Process last bytes. */
116 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
118 return md5_read_ctx (ctx, resbuf);
122 #ifdef NEED_MD5_STREAM
123 /* Compute MD5 message digest for bytes read from STREAM. The
124 resulting message digest number will be written into the 16 bytes
125 beginning at RESBLOCK. */
127 md5_stream (FILE *stream, void *resblock)
129 /* Important: BLOCKSIZE must be a multiple of 64. */
130 #define BLOCKSIZE 4096
132 char buffer[BLOCKSIZE + 72];
135 /* Initialize the computation context. */
138 /* Iterate over full file contents. */
141 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
142 computation function processes the whole buffer so that with the
143 next round of the loop another block can be read. */
147 /* Read block. Take care for partial reads. */
150 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
154 while (sum < BLOCKSIZE && n != 0);
155 if (n == 0 && ferror (stream))
158 /* If end of file is reached, end the loop. */
162 /* Process buffer with BLOCKSIZE bytes. Note that
165 md5_process_block (buffer, BLOCKSIZE, &ctx);
168 /* Add the last bytes if necessary. */
170 md5_process_bytes (buffer, sum, &ctx);
172 /* Construct result in desired memory. */
173 md5_finish_ctx (&ctx, resblock);
179 #ifdef NEED_MD5_BUFFER
180 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
181 result is always in little endian byte order, so that a byte-wise
182 output yields to the wanted ASCII representation of the message
185 md5_buffer (const char *buffer, size_t len, void *resblock)
189 /* Initialize the computation context. */
192 /* Process whole buffer but last len % 64 bytes. */
193 md5_process_bytes (buffer, len, &ctx);
195 /* Put result in desired memory area. */
196 return md5_finish_ctx (&ctx, resblock);
202 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
204 /* When we already have some bits in our internal buffer concatenate
205 both inputs first. */
206 if (ctx->buflen != 0)
208 size_t left_over = ctx->buflen;
209 size_t add = 128 - left_over > len ? len : 128 - left_over;
211 memcpy (&ctx->buffer[left_over], buffer, add);
214 if (ctx->buflen > 64)
216 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
219 /* The regions in the following copy operation cannot overlap. */
220 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
224 buffer = (const char *) buffer + add;
228 /* Process available complete blocks. */
231 #if !_STRING_ARCH_unaligned
232 /* To check alignment gcc has an appropriate operator. Other
235 # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0)
237 # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0)
239 if (UNALIGNED_P (buffer))
242 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
243 buffer = (const char *) buffer + 64;
249 md5_process_block (buffer, len & ~63, ctx);
250 buffer = (const char *) buffer + (len & ~63);
255 /* Move remaining bytes in internal buffer. */
258 size_t left_over = ctx->buflen;
260 memcpy (&ctx->buffer[left_over], buffer, len);
264 md5_process_block (ctx->buffer, 64, ctx);
266 memcpy (ctx->buffer, &ctx->buffer[64], left_over);
268 ctx->buflen = left_over;
273 /* These are the four functions used in the four steps of the MD5 algorithm
274 and defined in the RFC 1321. The first function is a little bit optimized
275 (as found in Colin Plumbs public domain implementation). */
276 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
277 #define FF(b, c, d) (d ^ (b & (c ^ d)))
278 #define FG(b, c, d) FF (d, b, c)
279 #define FH(b, c, d) (b ^ c ^ d)
280 #define FI(b, c, d) (c ^ (b | ~d))
282 /* Process LEN bytes of BUFFER, accumulating context into CTX.
283 It is assumed that LEN % 64 == 0. */
286 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
288 md5_uint32 correct_words[16];
289 const md5_uint32 *words = buffer;
290 size_t nwords = len / sizeof (md5_uint32);
291 const md5_uint32 *endp = words + nwords;
292 md5_uint32 A = ctx->A;
293 md5_uint32 B = ctx->B;
294 md5_uint32 C = ctx->C;
295 md5_uint32 D = ctx->D;
297 /* First increment the byte count. RFC 1321 specifies the possible
298 length of the file up to 2^64 bits. Here we only compute the
299 number of bytes. Do a double word increment. */
300 ctx->total[0] += len;
301 if (ctx->total[0] < len)
304 /* Process all bytes in the buffer with 64 bytes in each round of
308 md5_uint32 *cwp = correct_words;
309 md5_uint32 A_save = A;
310 md5_uint32 B_save = B;
311 md5_uint32 C_save = C;
312 md5_uint32 D_save = D;
314 /* First round: using the given function, the context and a constant
315 the next context is computed. Because the algorithms processing
316 unit is a 32-bit word and it is determined to work on words in
317 little endian byte order we perhaps have to change the byte order
318 before the computation. To reduce the work for the next steps
319 we store the swapped words in the array CORRECT_WORDS. */
321 #define OP(a, b, c, d, s, T) \
324 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
331 /* It is unfortunate that C does not provide an operator for
332 cyclic rotation. Hope the C compiler is smart enough. */
333 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
335 /* Before we start, one word to the strange constants.
336 They are defined in RFC 1321 as
338 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
342 OP (A, B, C, D, 7, 0xd76aa478);
343 OP (D, A, B, C, 12, 0xe8c7b756);
344 OP (C, D, A, B, 17, 0x242070db);
345 OP (B, C, D, A, 22, 0xc1bdceee);
346 OP (A, B, C, D, 7, 0xf57c0faf);
347 OP (D, A, B, C, 12, 0x4787c62a);
348 OP (C, D, A, B, 17, 0xa8304613);
349 OP (B, C, D, A, 22, 0xfd469501);
350 OP (A, B, C, D, 7, 0x698098d8);
351 OP (D, A, B, C, 12, 0x8b44f7af);
352 OP (C, D, A, B, 17, 0xffff5bb1);
353 OP (B, C, D, A, 22, 0x895cd7be);
354 OP (A, B, C, D, 7, 0x6b901122);
355 OP (D, A, B, C, 12, 0xfd987193);
356 OP (C, D, A, B, 17, 0xa679438e);
357 OP (B, C, D, A, 22, 0x49b40821);
359 /* For the second to fourth round we have the possibly swapped words
360 in CORRECT_WORDS. Redefine the macro to take an additional first
361 argument specifying the function to use. */
363 #define OP(f, a, b, c, d, k, s, T) \
366 a += f (b, c, d) + correct_words[k] + T; \
373 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
374 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
375 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
376 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
377 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
378 OP (FG, D, A, B, C, 10, 9, 0x02441453);
379 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
380 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
381 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
382 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
383 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
384 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
385 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
386 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
387 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
388 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
391 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
392 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
393 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
394 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
395 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
396 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
397 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
398 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
399 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
400 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
401 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
402 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
403 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
404 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
405 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
406 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
409 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
410 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
411 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
412 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
413 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
414 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
415 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
416 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
417 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
418 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
419 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
420 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
421 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
422 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
423 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
424 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
426 /* Add the starting values of the context. */
433 /* Put checksum in context given as argument. */