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, 1997 Free Software Foundation, Inc.
4   This file is part of the GNU C Library.
5
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 2 of the
9   License, or (at your option) any later version.
10
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.
15
16   You should have received a copy of the GNU Library General Public
17   License along with the GNU C Library; see the file COPYING.LIB.  If not,
18   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19   Boston, MA 02111-1307, USA.  */
20
21/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.  */
22
23#ifdef HAVE_CONFIG_H
24# include <config.h>
25#endif
26
27#include <sys/types.h>
28
29#if STDC_HEADERS || defined _LIBC
30# include <stdlib.h>
31# include <string.h>
32#else
33# ifndef HAVE_MEMCPY
34#  define memcpy(d, s, n) bcopy ((s), (d), (n))
35# endif
36#endif
37
38#include "md5-gnu.h"
39
40#ifdef _LIBC
41# include <endian.h>
42# if __BYTE_ORDER == __BIG_ENDIAN
43#  define WORDS_BIGENDIAN 1
44# endif
45/* We need to keep the namespace clean so define the MD5 function
46   protected using leading __ and use weak aliases.  */
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#ifdef WORDS_BIGENDIAN
57# define SWAP(n)							\
58    (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
59#else
60# define SWAP(n) (n)
61#endif
62
63
64/* This array contains the bytes used to pad the buffer to the next
65   64-byte boundary.  (RFC 1321, 3.1: Step 1)  */
66static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */ };
67
68
69/* Initialize structure containing state of computation.
70   (RFC 1321, 3.3: Step 3)  */
71void
72md5_init_ctx (ctx)
73     struct md5_ctx *ctx;
74{
75  ctx->A = 0x67452301;
76  ctx->B = 0xefcdab89;
77  ctx->C = 0x98badcfe;
78  ctx->D = 0x10325476;
79
80  ctx->total[0] = ctx->total[1] = 0;
81  ctx->buflen = 0;
82}
83
84/* Put result from CTX in first 16 bytes following RESBUF.  The result
85   must be in little endian byte order.
86
87   IMPORTANT: On some systems it is required that RESBUF is correctly
88   aligned for a 32 bits value.  */
89void *
90md5_read_ctx (ctx, resbuf)
91     const struct md5_ctx *ctx;
92     void *resbuf;
93{
94  ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
95  ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
96  ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
97  ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
98
99  return resbuf;
100}
101
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
105   IMPORTANT: On some systems it is required that RESBUF is correctly
106   aligned for a 32 bits value.  */
107void *
108md5_finish_ctx (ctx, resbuf)
109     struct md5_ctx *ctx;
110     void *resbuf;
111{
112  /* Take yet unprocessed bytes into account.  */
113  md5_uint32 bytes = ctx->buflen;
114  size_t pad;
115
116  /* Now count remaining bytes.  */
117  ctx->total[0] += bytes;
118  if (ctx->total[0] < bytes)
119    ++ctx->total[1];
120
121  pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
122  memcpy (&ctx->buffer[bytes], fillbuf, pad);
123
124  /* Put the 64-bit file length in *bits* at the end of the buffer.  */
125  *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
126  *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
127							(ctx->total[0] >> 29));
128
129  /* Process last bytes.  */
130  md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
131
132  return md5_read_ctx (ctx, resbuf);
133}
134
135/* Compute MD5 message digest for bytes read from STREAM.  The
136   resulting message digest number will be written into the 16 bytes
137   beginning at RESBLOCK.  */
138int
139md5_stream (stream, resblock)
140     FILE *stream;
141     void *resblock;
142{
143  /* Important: BLOCKSIZE must be a multiple of 64.  */
144#define BLOCKSIZE 4096
145  struct md5_ctx ctx;
146  char buffer[BLOCKSIZE + 72];
147  size_t sum;
148
149  /* Initialize the computation context.  */
150  md5_init_ctx (&ctx);
151
152  /* Iterate over full file contents.  */
153  while (1)
154    {
155      /* We read the file in blocks of BLOCKSIZE bytes.  One call of the
156	 computation function processes the whole buffer so that with the
157	 next round of the loop another block can be read.  */
158      size_t n;
159      sum = 0;
160
161      /* Read block.  Take care for partial reads.  */
162      do
163	{
164	  n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
165
166	  sum += n;
167	}
168      while (sum < BLOCKSIZE && n != 0);
169      if (n == 0 && ferror (stream))
170        return 1;
171
172      /* If end of file is reached, end the loop.  */
173      if (n == 0)
174	break;
175
176      /* Process buffer with BLOCKSIZE bytes.  Note that
177			BLOCKSIZE % 64 == 0
178       */
179      md5_process_block (buffer, BLOCKSIZE, &ctx);
180    }
181
182  /* Add the last bytes if necessary.  */
183  if (sum > 0)
184    md5_process_bytes (buffer, sum, &ctx);
185
186  /* Construct result in desired memory.  */
187  md5_finish_ctx (&ctx, resblock);
188  return 0;
189}
190
191/* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
192   result is always in little endian byte order, so that a byte-wise
193   output yields to the wanted ASCII representation of the message
194   digest.  */
195void *
196md5_buffer (buffer, len, resblock)
197     const char *buffer;
198     size_t len;
199     void *resblock;
200{
201  struct md5_ctx ctx;
202
203  /* Initialize the computation context.  */
204  md5_init_ctx (&ctx);
205
206  /* Process whole buffer but last len % 64 bytes.  */
207  md5_process_bytes (buffer, len, &ctx);
208
209  /* Put result in desired memory area.  */
210  return md5_finish_ctx (&ctx, resblock);
211}
212
213
214void
215md5_process_bytes (buffer, len, ctx)
216     const void *buffer;
217     size_t len;
218     struct md5_ctx *ctx;
219{
220  /* When we already have some bits in our internal buffer concatenate
221     both inputs first.  */
222  if (ctx->buflen != 0)
223    {
224      size_t left_over = ctx->buflen;
225      size_t add = 128 - left_over > len ? len : 128 - left_over;
226
227      memcpy (&ctx->buffer[left_over], buffer, add);
228      ctx->buflen += add;
229
230      if (left_over + add > 64)
231	{
232	  md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
233	  /* The regions in the following copy operation cannot overlap.  */
234	  memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
235		  (left_over + add) & 63);
236	  ctx->buflen = (left_over + add) & 63;
237	}
238
239      buffer = (const char *) buffer + add;
240      len -= add;
241    }
242
243  /* Process available complete blocks.  */
244  if (len > 64)
245    {
246      md5_process_block (buffer, len & ~63, ctx);
247      buffer = (const char *) buffer + (len & ~63);
248      len &= 63;
249    }
250
251  /* Move remaining bytes in internal buffer.  */
252  if (len > 0)
253    {
254      memcpy (ctx->buffer, buffer, len);
255      ctx->buflen = len;
256    }
257}
258
259
260/* These are the four functions used in the four steps of the MD5 algorithm
261   and defined in the RFC 1321.  The first function is a little bit optimized
262   (as found in Colin Plumbs public domain implementation).  */
263/* #define FF(b, c, d) ((b & c) | (~b & d)) */
264#define FF(b, c, d) (d ^ (b & (c ^ d)))
265#define FG(b, c, d) FF (d, b, c)
266#define FH(b, c, d) (b ^ c ^ d)
267#define FI(b, c, d) (c ^ (b | ~d))
268
269/* Process LEN bytes of BUFFER, accumulating context into CTX.
270   It is assumed that LEN % 64 == 0.  */
271
272void
273md5_process_block (buffer, len, ctx)
274     const void *buffer;
275     size_t len;
276     struct md5_ctx *ctx;
277{
278  md5_uint32 correct_words[16];
279  const md5_uint32 *words = buffer;
280  size_t nwords = len / sizeof (md5_uint32);
281  const md5_uint32 *endp = words + nwords;
282  md5_uint32 A = ctx->A;
283  md5_uint32 B = ctx->B;
284  md5_uint32 C = ctx->C;
285  md5_uint32 D = ctx->D;
286
287  /* First increment the byte count.  RFC 1321 specifies the possible
288     length of the file up to 2^64 bits.  Here we only compute the
289     number of bytes.  Do a double word increment.  */
290  ctx->total[0] += len;
291  if (ctx->total[0] < len)
292    ++ctx->total[1];
293
294  /* Process all bytes in the buffer with 64 bytes in each round of
295     the loop.  */
296  while (words < endp)
297    {
298      md5_uint32 *cwp = correct_words;
299      md5_uint32 A_save = A;
300      md5_uint32 B_save = B;
301      md5_uint32 C_save = C;
302      md5_uint32 D_save = D;
303
304      /* First round: using the given function, the context and a constant
305	 the next context is computed.  Because the algorithms processing
306	 unit is a 32-bit word and it is determined to work on words in
307	 little endian byte order we perhaps have to change the byte order
308	 before the computation.  To reduce the work for the next steps
309	 we store the swapped words in the array CORRECT_WORDS.  */
310
311#define OP(a, b, c, d, s, T)						\
312      do								\
313        {								\
314	  a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;		\
315	  ++words;							\
316	  CYCLIC (a, s);						\
317	  a += b;							\
318        }								\
319      while (0)
320
321      /* It is unfortunate that C does not provide an operator for
322	 cyclic rotation.  Hope the C compiler is smart enough.  */
323#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
324
325      /* Before we start, one word to the strange constants.
326	 They are defined in RFC 1321 as
327
328	 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
329       */
330
331      /* Round 1.  */
332      OP (A, B, C, D,  7, 0xd76aa478);
333      OP (D, A, B, C, 12, 0xe8c7b756);
334      OP (C, D, A, B, 17, 0x242070db);
335      OP (B, C, D, A, 22, 0xc1bdceee);
336      OP (A, B, C, D,  7, 0xf57c0faf);
337      OP (D, A, B, C, 12, 0x4787c62a);
338      OP (C, D, A, B, 17, 0xa8304613);
339      OP (B, C, D, A, 22, 0xfd469501);
340      OP (A, B, C, D,  7, 0x698098d8);
341      OP (D, A, B, C, 12, 0x8b44f7af);
342      OP (C, D, A, B, 17, 0xffff5bb1);
343      OP (B, C, D, A, 22, 0x895cd7be);
344      OP (A, B, C, D,  7, 0x6b901122);
345      OP (D, A, B, C, 12, 0xfd987193);
346      OP (C, D, A, B, 17, 0xa679438e);
347      OP (B, C, D, A, 22, 0x49b40821);
348
349      /* For the second to fourth round we have the possibly swapped words
350	 in CORRECT_WORDS.  Redefine the macro to take an additional first
351	 argument specifying the function to use.  */
352#undef OP
353#define OP(f, a, b, c, d, k, s, T)					\
354      do 								\
355	{								\
356	  a += f (b, c, d) + correct_words[k] + T;			\
357	  CYCLIC (a, s);						\
358	  a += b;							\
359	}								\
360      while (0)
361
362      /* Round 2.  */
363      OP (FG, A, B, C, D,  1,  5, 0xf61e2562);
364      OP (FG, D, A, B, C,  6,  9, 0xc040b340);
365      OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
366      OP (FG, B, C, D, A,  0, 20, 0xe9b6c7aa);
367      OP (FG, A, B, C, D,  5,  5, 0xd62f105d);
368      OP (FG, D, A, B, C, 10,  9, 0x02441453);
369      OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
370      OP (FG, B, C, D, A,  4, 20, 0xe7d3fbc8);
371      OP (FG, A, B, C, D,  9,  5, 0x21e1cde6);
372      OP (FG, D, A, B, C, 14,  9, 0xc33707d6);
373      OP (FG, C, D, A, B,  3, 14, 0xf4d50d87);
374      OP (FG, B, C, D, A,  8, 20, 0x455a14ed);
375      OP (FG, A, B, C, D, 13,  5, 0xa9e3e905);
376      OP (FG, D, A, B, C,  2,  9, 0xfcefa3f8);
377      OP (FG, C, D, A, B,  7, 14, 0x676f02d9);
378      OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
379
380      /* Round 3.  */
381      OP (FH, A, B, C, D,  5,  4, 0xfffa3942);
382      OP (FH, D, A, B, C,  8, 11, 0x8771f681);
383      OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
384      OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
385      OP (FH, A, B, C, D,  1,  4, 0xa4beea44);
386      OP (FH, D, A, B, C,  4, 11, 0x4bdecfa9);
387      OP (FH, C, D, A, B,  7, 16, 0xf6bb4b60);
388      OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
389      OP (FH, A, B, C, D, 13,  4, 0x289b7ec6);
390      OP (FH, D, A, B, C,  0, 11, 0xeaa127fa);
391      OP (FH, C, D, A, B,  3, 16, 0xd4ef3085);
392      OP (FH, B, C, D, A,  6, 23, 0x04881d05);
393      OP (FH, A, B, C, D,  9,  4, 0xd9d4d039);
394      OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
395      OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
396      OP (FH, B, C, D, A,  2, 23, 0xc4ac5665);
397
398      /* Round 4.  */
399      OP (FI, A, B, C, D,  0,  6, 0xf4292244);
400      OP (FI, D, A, B, C,  7, 10, 0x432aff97);
401      OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
402      OP (FI, B, C, D, A,  5, 21, 0xfc93a039);
403      OP (FI, A, B, C, D, 12,  6, 0x655b59c3);
404      OP (FI, D, A, B, C,  3, 10, 0x8f0ccc92);
405      OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
406      OP (FI, B, C, D, A,  1, 21, 0x85845dd1);
407      OP (FI, A, B, C, D,  8,  6, 0x6fa87e4f);
408      OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
409      OP (FI, C, D, A, B,  6, 15, 0xa3014314);
410      OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
411      OP (FI, A, B, C, D,  4,  6, 0xf7537e82);
412      OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
413      OP (FI, C, D, A, B,  2, 15, 0x2ad7d2bb);
414      OP (FI, B, C, D, A,  9, 21, 0xeb86d391);
415
416      /* Add the starting values of the context.  */
417      A += A_save;
418      B += B_save;
419      C += C_save;
420      D += D_save;
421    }
422
423  /* Put checksum in context given as argument.  */
424  ctx->A = A;
425  ctx->B = B;
426  ctx->C = C;
427  ctx->D = D;
428}
429
430
431#ifdef _LIBC
432/* Define weak aliases.  */
433# undef md5_init_ctx
434weak_alias (__md5_init_ctx, md5_init_ctx)
435# undef md5_process_block
436weak_alias (__md5_process_block, md5_process_block)
437# undef md5_process_bytes
438weak_alias (__md5_process_bytes, md5_process_bytes)
439# undef md5_finish_ctx
440weak_alias (__md5_finish_ctx, md5_finish_ctx)
441# undef md5_read_ctx
442weak_alias (__md5_read_ctx, md5_read_ctx)
443# undef md5_stream
444weak_alias (__md5_stream, md5_stream)
445# undef md5_buffer
446weak_alias (__md5_buffer, md5_buffer)
447#endif
448