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 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) */
60 ctx->total[0] = ctx->total[1] = 0;
64 /* Put result from CTX in first 16 bytes following RESBUF. The result
65 must be in little endian byte order.
67 IMPORTANT: On some systems it is required that RESBUF is correctly
68 aligned for a 32 bits value. */
70 md5_read_ctx (ctx, resbuf)
71 const struct md5_ctx *ctx;
74 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
75 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
76 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
77 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
83 le64_copy (char *dest, uint64_t x)
85 for (size_t i = 0; i < 8; ++i)
87 dest[i] = (uint8_t) x;
92 /* Process the remaining bytes in the internal buffer and the usual
93 prolog according to the standard and write the result to RESBUF.
95 IMPORTANT: On some systems it is required that RESBUF is correctly
96 aligned for a 32 bits value. */
98 md5_finish_ctx (ctx, resbuf)
102 /* Take yet unprocessed bytes into account. */
103 md5_uint32 bytes = ctx->buflen;
106 /* Now count remaining bytes. */
107 ctx->total[0] += bytes;
108 if (ctx->total[0] < bytes)
111 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
112 memcpy (&ctx->buffer[bytes], fillbuf, pad);
114 /* Put the 64-bit file length in *bits* at the end of the buffer. */
115 const uint64_t bit_length = ((ctx->total[0] << 3)
116 + ((uint64_t) ((ctx->total[1] << 3) |
117 (ctx->total[0] >> 29)) << 32));
118 le64_copy (&ctx->buffer[bytes + pad], bit_length);
120 /* Process last bytes. */
121 md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
123 return md5_read_ctx (ctx, resbuf);
127 #ifdef NEED_MD5_STREAM
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. */
132 md5_stream (stream, resblock)
136 /* Important: BLOCKSIZE must be a multiple of 64. */
137 #define BLOCKSIZE 4096
139 char buffer[BLOCKSIZE + 72];
142 /* Initialize the computation context. */
145 /* Iterate over full file contents. */
148 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
149 computation function processes the whole buffer so that with the
150 next round of the loop another block can be read. */
154 /* Read block. Take care for partial reads. */
157 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
161 while (sum < BLOCKSIZE && n != 0);
162 if (n == 0 && ferror (stream))
165 /* If end of file is reached, end the loop. */
169 /* Process buffer with BLOCKSIZE bytes. Note that
172 md5_process_block (buffer, BLOCKSIZE, &ctx);
175 /* Add the last bytes if necessary. */
177 md5_process_bytes (buffer, sum, &ctx);
179 /* Construct result in desired memory. */
180 md5_finish_ctx (&ctx, resblock);
186 #ifdef NEED_MD5_BUFFER
187 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
188 result is always in little endian byte order, so that a byte-wise
189 output yields to the wanted ASCII representation of the message
192 md5_buffer (buffer, len, resblock)
199 /* Initialize the computation context. */
202 /* Process whole buffer but last len % 64 bytes. */
203 md5_process_bytes (buffer, len, &ctx);
205 /* Put result in desired memory area. */
206 return md5_finish_ctx (&ctx, resblock);
212 md5_process_bytes (buffer, len, ctx)
217 /* When we already have some bits in our internal buffer concatenate
218 both inputs first. */
219 if (ctx->buflen != 0)
221 size_t left_over = ctx->buflen;
222 size_t add = 128 - left_over > len ? len : 128 - left_over;
224 memcpy (&ctx->buffer[left_over], buffer, add);
227 if (ctx->buflen > 64)
229 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
232 /* The regions in the following copy operation cannot overlap. */
233 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
237 buffer = (const char *) buffer + add;
241 /* Process available complete blocks. */
244 #if !_STRING_ARCH_unaligned
245 /* To check alignment gcc has an appropriate operator. Other
248 # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0)
250 # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0)
252 if (UNALIGNED_P (buffer))
255 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
256 buffer = (const char *) buffer + 64;
262 md5_process_block (buffer, len & ~63, ctx);
263 buffer = (const char *) buffer + (len & ~63);
268 /* Move remaining bytes in internal buffer. */
271 size_t left_over = ctx->buflen;
273 memcpy (&ctx->buffer[left_over], buffer, len);
277 md5_process_block (ctx->buffer, 64, ctx);
279 memcpy (ctx->buffer, &ctx->buffer[64], left_over);
281 ctx->buflen = left_over;
286 /* These are the four functions used in the four steps of the MD5 algorithm
287 and defined in the RFC 1321. The first function is a little bit optimized
288 (as found in Colin Plumbs public domain implementation). */
289 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
290 #define FF(b, c, d) (d ^ (b & (c ^ d)))
291 #define FG(b, c, d) FF (d, b, c)
292 #define FH(b, c, d) (b ^ c ^ d)
293 #define FI(b, c, d) (c ^ (b | ~d))
295 /* Process LEN bytes of BUFFER, accumulating context into CTX.
296 It is assumed that LEN % 64 == 0. */
299 md5_process_block (buffer, len, ctx)
304 md5_uint32 correct_words[16];
305 const md5_uint32 *words = buffer;
306 size_t nwords = len / sizeof (md5_uint32);
307 const md5_uint32 *endp = words + nwords;
308 md5_uint32 A = ctx->A;
309 md5_uint32 B = ctx->B;
310 md5_uint32 C = ctx->C;
311 md5_uint32 D = ctx->D;
313 /* First increment the byte count. RFC 1321 specifies the possible
314 length of the file up to 2^64 bits. Here we only compute the
315 number of bytes. Do a double word increment. */
316 ctx->total[0] += len;
317 if (ctx->total[0] < len)
320 /* Process all bytes in the buffer with 64 bytes in each round of
324 md5_uint32 *cwp = correct_words;
325 md5_uint32 A_save = A;
326 md5_uint32 B_save = B;
327 md5_uint32 C_save = C;
328 md5_uint32 D_save = D;
330 /* First round: using the given function, the context and a constant
331 the next context is computed. Because the algorithms processing
332 unit is a 32-bit word and it is determined to work on words in
333 little endian byte order we perhaps have to change the byte order
334 before the computation. To reduce the work for the next steps
335 we store the swapped words in the array CORRECT_WORDS. */
337 #define OP(a, b, c, d, s, T) \
340 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
347 /* It is unfortunate that C does not provide an operator for
348 cyclic rotation. Hope the C compiler is smart enough. */
349 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
351 /* Before we start, one word to the strange constants.
352 They are defined in RFC 1321 as
354 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
358 OP (A, B, C, D, 7, 0xd76aa478);
359 OP (D, A, B, C, 12, 0xe8c7b756);
360 OP (C, D, A, B, 17, 0x242070db);
361 OP (B, C, D, A, 22, 0xc1bdceee);
362 OP (A, B, C, D, 7, 0xf57c0faf);
363 OP (D, A, B, C, 12, 0x4787c62a);
364 OP (C, D, A, B, 17, 0xa8304613);
365 OP (B, C, D, A, 22, 0xfd469501);
366 OP (A, B, C, D, 7, 0x698098d8);
367 OP (D, A, B, C, 12, 0x8b44f7af);
368 OP (C, D, A, B, 17, 0xffff5bb1);
369 OP (B, C, D, A, 22, 0x895cd7be);
370 OP (A, B, C, D, 7, 0x6b901122);
371 OP (D, A, B, C, 12, 0xfd987193);
372 OP (C, D, A, B, 17, 0xa679438e);
373 OP (B, C, D, A, 22, 0x49b40821);
375 /* For the second to fourth round we have the possibly swapped words
376 in CORRECT_WORDS. Redefine the macro to take an additional first
377 argument specifying the function to use. */
379 #define OP(f, a, b, c, d, k, s, T) \
382 a += f (b, c, d) + correct_words[k] + T; \
389 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
390 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
391 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
392 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
393 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
394 OP (FG, D, A, B, C, 10, 9, 0x02441453);
395 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
396 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
397 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
398 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
399 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
400 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
401 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
402 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
403 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
404 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
407 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
408 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
409 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
410 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
411 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
412 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
413 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
414 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
415 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
416 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
417 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
418 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
419 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
420 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
421 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
422 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
425 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
426 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
427 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
428 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
429 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
430 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
431 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
432 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
433 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
434 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
435 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
436 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
437 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
438 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
439 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
440 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
442 /* Add the starting values of the context. */
449 /* Put checksum in context given as argument. */