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, 2002, 2003, 2004,
  4                  2005, 2006, 2007  Free Software Foundation, Inc.
  5 
  6    This file is part of the GNU C Library.
  7 
  8    The GNU C Library is free software; you can redistribute it and/or
  9    modify it under the terms of the GNU General Public License as
 10    published by the Free Software Foundation; either version 2 of the
 11    License, or (at your option) any later version.
 12 
 13    The GNU C Library is distributed in the hope that it will be useful,
 14    but WITHOUT ANY WARRANTY; without even the implied warranty of
 15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 16    General Public License for more details.
 17 
 18    You should have received a copy of the GNU General Public License
 19    along with the GNU C Library; see the file COPYING.  If not, write to the
 20    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 21    Boston, MA 02110-1301, USA.  */
 22 
 23 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.  */
 24 
 25 #ifdef HAVE_CONFIG_H
 26 # include <config.h>
 27 #endif
 28 
 29 #include <sys/types.h>
 30 
 31 #if STDC_HEADERS || defined _LIBC
 32 # include <stdlib.h>
 33 # include <string.h>
 34 #else
 35 # ifndef HAVE_MEMCPY
 36 #  define memcpy(d, s, n) bcopy ((s), (d), (n))
 37 # endif
 38 #endif
 39 
 40 #ifdef _LIBC
 41 # include <endian.h>
 42 # if __BYTE_ORDER == __BIG_ENDIAN
 43 #  define WORDS_BIG_ENDIAN 1
 44 # endif
 45 /* We need to keep the namespace clean so define the MD5 function
 46    protected using leading __ .  */
 47 # define md5_init_ctx __md5_init_ctx
 48 # define md5_process_block __md5_process_block
 49 # define md5_process_bytes __md5_process_bytes
 50 # define md5_finish_ctx __md5_finish_ctx
 51 # define md5_read_ctx __md5_read_ctx
 52 # define md5_stream __md5_stream
 53 # define md5_buffer __md5_buffer
 54 #endif
 55 
 56 #include "md5.h"
 57 
 58 #ifdef WORDS_BIG_ENDIAN
 59 # define SWAP(n)                                                        \
 60     (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
 61 #else
 62 # define SWAP(n) (n)
 63 #endif
 64 
 65 
 66 /* This array contains the bytes used to pad the buffer to the next
 67    64-byte boundary.  (RFC 1321, 3.1: Step 1)  */
 68 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */ };
 69 
 70 
 71 /* Initialize structure containing state of computation.
 72    (RFC 1321, 3.3: Step 3)  */
 73 void
 74 md5_init_ctx (ctx)
 75      struct md5_ctx *ctx;
 76 {
 77   ctx->A = 0x67452301;
 78   ctx->B = 0xefcdab89;
 79   ctx->C = 0x98badcfe;
 80   ctx->D = 0x10325476;
 81 
 82   ctx->total[0] = ctx->total[1] = 0;
 83   ctx->buflen = 0;
 84 }
 85 
 86 /* Put result from CTX in first 16 bytes following RESBUF.  The result
 87    must be in little endian byte order.
 88 
 89    IMPORTANT: On some systems it is required that RESBUF is correctly
 90    aligned for a 32 bits value.  */
 91 void *
 92 md5_read_ctx (ctx, resbuf)
 93      const struct md5_ctx *ctx;
 94      void *resbuf;
 95 {
 96   ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
 97   ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
 98   ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
 99   ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
100 
101   return resbuf;
102 }
103 
104 /* Process the remaining bytes in the internal buffer and the usual
105    prolog according to the standard and write the result to RESBUF.
106 
107    IMPORTANT: On some systems it is required that RESBUF is correctly
108    aligned for a 32 bits value.  */
109 void *
110 md5_finish_ctx (ctx, resbuf)
111      struct md5_ctx *ctx;
112      void *resbuf;
113 {
114   /* Take yet unprocessed bytes into account.  */
115   md5_uint32 bytes = ctx->buflen;
116   size_t pad;
117 
118   /* Now count remaining bytes.  */
119   ctx->total[0] += bytes;
120   if (ctx->total[0] < bytes)
121     ++ctx->total[1];
122 
123   pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
124   memcpy (&ctx->buffer[bytes], fillbuf, pad);
125 
126   /* Put the 64-bit file length in *bits* at the end of the buffer.  */
127   *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
128   *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
129                                                         (ctx->total[0] >> 29));
130 
131   /* Process last bytes.  */
132   md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
133 
134   return md5_read_ctx (ctx, resbuf);
135 }
136 
137 /* Compute MD5 message digest for bytes read from STREAM.  The
138    resulting message digest number will be written into the 16 bytes
139    beginning at RESBLOCK.  */
140 int
141 md5_stream (stream, resblock)
142      FILE *stream;
143      void *resblock;
144 {
145   /* Important: BLOCKSIZE must be a multiple of 64.  */
146 #define BLOCKSIZE 4096
147   struct md5_ctx ctx;
148   char buffer[BLOCKSIZE + 72];
149   size_t sum;
150 
151   /* Initialize the computation context.  */
152   md5_init_ctx (&ctx);
153 
154   /* Iterate over full file contents.  */
155   while (1)
156     {
157       /* We read the file in blocks of BLOCKSIZE bytes.  One call of the
158          computation function processes the whole buffer so that with the
159          next round of the loop another block can be read.  */
160       size_t n;
161       sum = 0;
162 
163       /* Read block.  Take care for partial reads.  */
164       do
165         {
166           n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
167 
168           sum += n;
169         }
170       while (sum < BLOCKSIZE && n != 0);
171       if (n == 0 && ferror (stream))
172         return 1;
173 
174       /* If end of file is reached, end the loop.  */
175       if (n == 0)
176         break;
177 
178       /* Process buffer with BLOCKSIZE bytes.  Note that
179                         BLOCKSIZE % 64 == 0
180        */
181       md5_process_block (buffer, BLOCKSIZE, &ctx);
182     }
183 
184   /* Add the last bytes if necessary.  */
185   if (sum > 0)
186     md5_process_bytes (buffer, sum, &ctx);
187 
188   /* Construct result in desired memory.  */
189   md5_finish_ctx (&ctx, resblock);
190   return 0;
191 }
192 
193 /* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
194    result is always in little endian byte order, so that a byte-wise
195    output yields to the wanted ASCII representation of the message
196    digest.  */
197 void *
198 md5_buffer (buffer, len, resblock)
199      const char *buffer;
200      size_t len;
201      void *resblock;
202 {
203   struct md5_ctx ctx;
204 
205   /* Initialize the computation context.  */
206   md5_init_ctx (&ctx);
207 
208   /* Process whole buffer but last len % 64 bytes.  */
209   md5_process_bytes (buffer, len, &ctx);
210 
211   /* Put result in desired memory area.  */
212   return md5_finish_ctx (&ctx, resblock);
213 }
214 
215 
216 void
217 md5_process_bytes (buffer, len, ctx)
218      const void *buffer;
219      size_t len;
220      struct md5_ctx *ctx;
221 {
222   /* const void aligned_buffer = buffer; */
223 
224   /* When we already have some bits in our internal buffer concatenate
225      both inputs first.  */
226   if (ctx->buflen != 0)
227     {
228       size_t left_over = ctx->buflen;
229       size_t add = 128 - left_over > len ? len : 128 - left_over;
230 
231       /* Only put full words in the buffer.  */
232       add -= add % __alignof__ (md5_uint32);
233 
234       memcpy (&ctx->buffer[left_over], buffer, add);
235       ctx->buflen += add;
236 
237       if (ctx->buflen > 64)
238         {
239           md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
240 
241           ctx->buflen &= 63;
242           /* The regions in the following copy operation cannot overlap.  */
243           memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
244                   ctx->buflen);
245         }
246 
247       buffer = (const char *) buffer + add;
248       len -= add;
249     }
250 
251   /* Process available complete blocks.  */
252   if (len > 64)
253     {
254       md5_process_block (buffer, len & ~63, ctx);
255       buffer = (const char *) buffer + (len & ~63);
256       len &= 63;
257     }
258 
259   /* Move remaining bytes in internal buffer.  */
260   if (len > 0)
261     {
262       size_t left_over = ctx->buflen;
263 
264       memcpy (&ctx->buffer[left_over], buffer, len);
265       left_over += len;
266       if (left_over >= 64)
267         {
268           md5_process_block (ctx->buffer, 64, ctx);
269           left_over -= 64;
270           memcpy (ctx->buffer, &ctx->buffer[64], left_over);
271         }
272       ctx->buflen = left_over;
273     }
274 }
275 
276 
277 /* These are the four functions used in the four steps of the MD5 algorithm
278    and defined in the RFC 1321.  The first function is a little bit optimized
279    (as found in Colin Plumbs public domain implementation).  */
280 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
281 #define FF(b, c, d) (d ^ (b & (c ^ d)))
282 #define FG(b, c, d) FF (d, b, c)
283 #define FH(b, c, d) (b ^ c ^ d)
284 #define FI(b, c, d) (c ^ (b | ~d))
285 
286 /* Process LEN bytes of BUFFER, accumulating context into CTX.
287    It is assumed that LEN % 64 == 0.  */
288 
289 void
290 md5_process_block (buffer, len, ctx)
291      const void *buffer;
292      size_t len;
293      struct md5_ctx *ctx;
294 {
295   md5_uint32 correct_words[16];
296   const md5_uint32 *words = buffer;
297   size_t nwords = len / sizeof (md5_uint32);
298   const md5_uint32 *endp = words + nwords;
299   md5_uint32 A = ctx->A;
300   md5_uint32 B = ctx->B;
301   md5_uint32 C = ctx->C;
302   md5_uint32 D = ctx->D;
303 
304   /* First increment the byte count.  RFC 1321 specifies the possible
305      length of the file up to 2^64 bits.  Here we only compute the
306      number of bytes.  Do a double word increment.  */
307   ctx->total[0] += len;
308   if (ctx->total[0] < len)
309     ++ctx->total[1];
310 
311   /* Process all bytes in the buffer with 64 bytes in each round of
312      the loop.  */
313   while (words < endp)
314     {
315       md5_uint32 *cwp = correct_words;
316       md5_uint32 A_save = A;
317       md5_uint32 B_save = B;
318       md5_uint32 C_save = C;
319       md5_uint32 D_save = D;
320 
321       /* First round: using the given function, the context and a constant
322          the next context is computed.  Because the algorithms processing
323          unit is a 32-bit word and it is determined to work on words in
324          little endian byte order we perhaps have to change the byte order
325          before the computation.  To reduce the work for the next steps
326          we store the swapped words in the array CORRECT_WORDS.  */
327 
328 #define OP(a, b, c, d, s, T)                                            \
329       do                                                                \
330         {                                                               \
331           a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;             \
332           ++words;                                                      \
333           CYCLIC (a, s);                                                \
334           a += b;                                                       \
335         }                                                               \
336       while (0)
337 
338       /* It is unfortunate that C does not provide an operator for
339          cyclic rotation.  Hope the C compiler is smart enough.  */
340 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
341 
342       /* Before we start, one word to the strange constants.
343          They are defined in RFC 1321 as
344 
345          T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
346        */
347 
348       /* Round 1.  */
349       OP (A, B, C, D,  7, 0xd76aa478);
350       OP (D, A, B, C, 12, 0xe8c7b756);
351       OP (C, D, A, B, 17, 0x242070db);
352       OP (B, C, D, A, 22, 0xc1bdceee);
353       OP (A, B, C, D,  7, 0xf57c0faf);
354       OP (D, A, B, C, 12, 0x4787c62a);
355       OP (C, D, A, B, 17, 0xa8304613);
356       OP (B, C, D, A, 22, 0xfd469501);
357       OP (A, B, C, D,  7, 0x698098d8);
358       OP (D, A, B, C, 12, 0x8b44f7af);
359       OP (C, D, A, B, 17, 0xffff5bb1);
360       OP (B, C, D, A, 22, 0x895cd7be);
361       OP (A, B, C, D,  7, 0x6b901122);
362       OP (D, A, B, C, 12, 0xfd987193);
363       OP (C, D, A, B, 17, 0xa679438e);
364       OP (B, C, D, A, 22, 0x49b40821);
365 
366       /* For the second to fourth round we have the possibly swapped words
367          in CORRECT_WORDS.  Redefine the macro to take an additional first
368          argument specifying the function to use.  */
369 #undef OP
370 #define OP(f, a, b, c, d, k, s, T)                                      \
371       do                                                                \
372         {                                                               \
373           a += f (b, c, d) + correct_words[k] + T;                      \
374           CYCLIC (a, s);                                                \
375           a += b;                                                       \
376         }                                                               \
377       while (0)
378 
379       /* Round 2.  */
380       OP (FG, A, B, C, D,  1,  5, 0xf61e2562);
381       OP (FG, D, A, B, C,  6,  9, 0xc040b340);
382       OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
383       OP (FG, B, C, D, A,  0, 20, 0xe9b6c7aa);
384       OP (FG, A, B, C, D,  5,  5, 0xd62f105d);
385       OP (FG, D, A, B, C, 10,  9, 0x02441453);
386       OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
387       OP (FG, B, C, D, A,  4, 20, 0xe7d3fbc8);
388       OP (FG, A, B, C, D,  9,  5, 0x21e1cde6);
389       OP (FG, D, A, B, C, 14,  9, 0xc33707d6);
390       OP (FG, C, D, A, B,  3, 14, 0xf4d50d87);
391       OP (FG, B, C, D, A,  8, 20, 0x455a14ed);
392       OP (FG, A, B, C, D, 13,  5, 0xa9e3e905);
393       OP (FG, D, A, B, C,  2,  9, 0xfcefa3f8);
394       OP (FG, C, D, A, B,  7, 14, 0x676f02d9);
395       OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
396 
397       /* Round 3.  */
398       OP (FH, A, B, C, D,  5,  4, 0xfffa3942);
399       OP (FH, D, A, B, C,  8, 11, 0x8771f681);
400       OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
401       OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
402       OP (FH, A, B, C, D,  1,  4, 0xa4beea44);
403       OP (FH, D, A, B, C,  4, 11, 0x4bdecfa9);
404       OP (FH, C, D, A, B,  7, 16, 0xf6bb4b60);
405       OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
406       OP (FH, A, B, C, D, 13,  4, 0x289b7ec6);
407       OP (FH, D, A, B, C,  0, 11, 0xeaa127fa);
408       OP (FH, C, D, A, B,  3, 16, 0xd4ef3085);
409       OP (FH, B, C, D, A,  6, 23, 0x04881d05);
410       OP (FH, A, B, C, D,  9,  4, 0xd9d4d039);
411       OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
412       OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
413       OP (FH, B, C, D, A,  2, 23, 0xc4ac5665);
414 
415       /* Round 4.  */
416       OP (FI, A, B, C, D,  0,  6, 0xf4292244);
417       OP (FI, D, A, B, C,  7, 10, 0x432aff97);
418       OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
419       OP (FI, B, C, D, A,  5, 21, 0xfc93a039);
420       OP (FI, A, B, C, D, 12,  6, 0x655b59c3);
421       OP (FI, D, A, B, C,  3, 10, 0x8f0ccc92);
422       OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
423       OP (FI, B, C, D, A,  1, 21, 0x85845dd1);
424       OP (FI, A, B, C, D,  8,  6, 0x6fa87e4f);
425       OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
426       OP (FI, C, D, A, B,  6, 15, 0xa3014314);
427       OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
428       OP (FI, A, B, C, D,  4,  6, 0xf7537e82);
429       OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
430       OP (FI, C, D, A, B,  2, 15, 0x2ad7d2bb);
431       OP (FI, B, C, D, A,  9, 21, 0xeb86d391);
432 
433       /* Add the starting values of the context.  */
434       A += A_save;
435       B += B_save;
436       C += C_save;
437       D += D_save;
438     }
439 
440   /* Put checksum in context given as argument.  */
441   ctx->A = A;
442   ctx->B = B;
443   ctx->C = C;
444   ctx->D = D;
445 }
446 
447 /* arch-tag: 60084f04-b434-42cb-9d2b-e91df01f4325
448    (do not change this comment) */