1/* sha1.c - Functions to compute SHA1 message digest of files or
2   memory blocks according to the NIST specification FIPS-180-1.
3
4   Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2008 Free Software
5   Foundation, Inc.
6
7   This program is free software; you can redistribute it and/or modify it
8   under the terms of the GNU General Public License as published by the
9   Free Software Foundation; either version 2, or (at your option) any
10   later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program; if not, write to the Free Software Foundation,
19   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
20
21/* Written by Scott G. Miller
22   Credits:
23      Robert Klep <robert@ilse.nl>  -- Expansion function fix
24*/
25
26#include <config.h>
27
28#include "sha1.h"
29
30#include <stddef.h>
31#include <string.h>
32
33#if USE_UNLOCKED_IO
34# include "unlocked-io.h"
35#endif
36
37#ifdef WORDS_BIGENDIAN
38# define SWAP(n) (n)
39#else
40# define SWAP(n) \
41    (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
42#endif
43
44#define BLOCKSIZE 4096
45#if BLOCKSIZE % 64 != 0
46# error "invalid BLOCKSIZE"
47#endif
48
49/* This array contains the bytes used to pad the buffer to the next
50   64-byte boundary.  (RFC 1321, 3.1: Step 1)  */
51static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */ };
52
53
54/* Take a pointer to a 160 bit block of data (five 32 bit ints) and
55   initialize it to the start constants of the SHA1 algorithm.  This
56   must be called before using hash in the call to sha1_hash.  */
57void
58sha1_init_ctx (struct sha1_ctx *ctx)
59{
60  ctx->A = 0x67452301;
61  ctx->B = 0xefcdab89;
62  ctx->C = 0x98badcfe;
63  ctx->D = 0x10325476;
64  ctx->E = 0xc3d2e1f0;
65
66  ctx->total[0] = ctx->total[1] = 0;
67  ctx->buflen = 0;
68}
69
70/* Put result from CTX in first 20 bytes following RESBUF.  The result
71   must be in little endian byte order.
72
73   IMPORTANT: On some systems it is required that RESBUF is correctly
74   aligned for a 32-bit value.  */
75void *
76sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf)
77{
78  ((sha1_uint32 *) resbuf)[0] = SWAP (ctx->A);
79  ((sha1_uint32 *) resbuf)[1] = SWAP (ctx->B);
80  ((sha1_uint32 *) resbuf)[2] = SWAP (ctx->C);
81  ((sha1_uint32 *) resbuf)[3] = SWAP (ctx->D);
82  ((sha1_uint32 *) resbuf)[4] = SWAP (ctx->E);
83
84  return resbuf;
85}
86
87/* Process the remaining bytes in the internal buffer and the usual
88   prolog according to the standard and write the result to RESBUF.
89
90   IMPORTANT: On some systems it is required that RESBUF is correctly
91   aligned for a 32-bit value.  */
92void *
93sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf)
94{
95  /* Take yet unprocessed bytes into account.  */
96  sha1_uint32 bytes = ctx->buflen;
97  size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
98
99  /* Now count remaining bytes.  */
100  ctx->total[0] += bytes;
101  if (ctx->total[0] < bytes)
102    ++ctx->total[1];
103
104  /* Put the 64-bit file length in *bits* at the end of the buffer.  */
105  ctx->buffer[size - 2] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
106  ctx->buffer[size - 1] = SWAP (ctx->total[0] << 3);
107
108  memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
109
110  /* Process last bytes.  */
111  sha1_process_block (ctx->buffer, size * 4, ctx);
112
113  return sha1_read_ctx (ctx, resbuf);
114}
115
116/* Compute SHA1 message digest for bytes read from STREAM.  The
117   resulting message digest number will be written into the 16 bytes
118   beginning at RESBLOCK.  */
119int
120sha1_stream (FILE *stream, void *resblock)
121{
122  struct sha1_ctx ctx;
123  char buffer[BLOCKSIZE + 72];
124  size_t sum;
125
126  /* Initialize the computation context.  */
127  sha1_init_ctx (&ctx);
128
129  /* Iterate over full file contents.  */
130  while (1)
131    {
132      /* We read the file in blocks of BLOCKSIZE bytes.  One call of the
133	 computation function processes the whole buffer so that with the
134	 next round of the loop another block can be read.  */
135      size_t n;
136      sum = 0;
137
138      /* Read block.  Take care for partial reads.  */
139      while (1)
140	{
141	  n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
142
143	  sum += n;
144
145	  if (sum == BLOCKSIZE)
146	    break;
147
148	  if (n == 0)
149	    {
150	      /* Check for the error flag IFF N == 0, so that we don't
151		 exit the loop after a partial read due to e.g., EAGAIN
152		 or EWOULDBLOCK.  */
153	      if (ferror (stream))
154		return 1;
155	      goto process_partial_block;
156	    }
157
158	  /* We've read at least one byte, so ignore errors.  But always
159	     check for EOF, since feof may be true even though N > 0.
160	     Otherwise, we could end up calling fread after EOF.  */
161	  if (feof (stream))
162	    goto process_partial_block;
163	}
164
165      /* Process buffer with BLOCKSIZE bytes.  Note that
166			BLOCKSIZE % 64 == 0
167       */
168      sha1_process_block (buffer, BLOCKSIZE, &ctx);
169    }
170
171 process_partial_block:;
172
173  /* Process any remaining bytes.  */
174  if (sum > 0)
175    sha1_process_bytes (buffer, sum, &ctx);
176
177  /* Construct result in desired memory.  */
178  sha1_finish_ctx (&ctx, resblock);
179  return 0;
180}
181
182/* Compute SHA1 message digest for LEN bytes beginning at BUFFER.  The
183   result is always in little endian byte order, so that a byte-wise
184   output yields to the wanted ASCII representation of the message
185   digest.  */
186void *
187sha1_buffer (const char *buffer, size_t len, void *resblock)
188{
189  struct sha1_ctx ctx;
190
191  /* Initialize the computation context.  */
192  sha1_init_ctx (&ctx);
193
194  /* Process whole buffer but last len % 64 bytes.  */
195  sha1_process_bytes (buffer, len, &ctx);
196
197  /* Put result in desired memory area.  */
198  return sha1_finish_ctx (&ctx, resblock);
199}
200
201void
202sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx)
203{
204  /* When we already have some bits in our internal buffer concatenate
205     both inputs first.  */
206  if (ctx->buflen != 0)
207    {
208      size_t left_over = ctx->buflen;
209      size_t add = 128 - left_over > len ? len : 128 - left_over;
210
211      memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
212      ctx->buflen += add;
213
214      if (ctx->buflen > 64)
215	{
216	  sha1_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
217
218	  ctx->buflen &= 63;
219	  /* The regions in the following copy operation cannot overlap.  */
220	  memcpy (ctx->buffer,
221		  &((char *) ctx->buffer)[(left_over + add) & ~63],
222		  ctx->buflen);
223	}
224
225      buffer = (const char *) buffer + add;
226      len -= add;
227    }
228
229  /* Process available complete blocks.  */
230  if (len >= 64)
231    {
232#if !_STRING_ARCH_unaligned
233# define alignof(type) offsetof (struct { char c; type x; }, x)
234# define UNALIGNED_P(p) (((size_t) p) % alignof (sha1_uint32) != 0)
235      if (UNALIGNED_P (buffer))
236	while (len > 64)
237	  {
238	    sha1_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
239	    buffer = (const char *) buffer + 64;
240	    len -= 64;
241	  }
242      else
243#endif
244	{
245	  sha1_process_block (buffer, len & ~63, ctx);
246	  buffer = (const char *) buffer + (len & ~63);
247	  len &= 63;
248	}
249    }
250
251  /* Move remaining bytes in internal buffer.  */
252  if (len > 0)
253    {
254      size_t left_over = ctx->buflen;
255
256      memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
257      left_over += len;
258      if (left_over >= 64)
259	{
260	  sha1_process_block (ctx->buffer, 64, ctx);
261	  left_over -= 64;
262	  memcpy (ctx->buffer, &ctx->buffer[16], left_over);
263	}
264      ctx->buflen = left_over;
265    }
266}
267
268/* --- Code below is the primary difference between md5.c and sha1.c --- */
269
270/* SHA1 round constants */
271#define K1 0x5a827999
272#define K2 0x6ed9eba1
273#define K3 0x8f1bbcdc
274#define K4 0xca62c1d6
275
276/* Round functions.  Note that F2 is the same as F4.  */
277#define F1(B,C,D) ( D ^ ( B & ( C ^ D ) ) )
278#define F2(B,C,D) (B ^ C ^ D)
279#define F3(B,C,D) ( ( B & C ) | ( D & ( B | C ) ) )
280#define F4(B,C,D) (B ^ C ^ D)
281
282/* Process LEN bytes of BUFFER, accumulating context into CTX.
283   It is assumed that LEN % 64 == 0.
284   Most of this code comes from GnuPG's cipher/sha1.c.  */
285
286void
287sha1_process_block (const void *buffer, size_t len, struct sha1_ctx *ctx)
288{
289  const sha1_uint32 *words = (const sha1_uint32*) buffer;
290  size_t nwords = len / sizeof (sha1_uint32);
291  const sha1_uint32 *endp = words + nwords;
292  sha1_uint32 x[16];
293  sha1_uint32 a = ctx->A;
294  sha1_uint32 b = ctx->B;
295  sha1_uint32 c = ctx->C;
296  sha1_uint32 d = ctx->D;
297  sha1_uint32 e = ctx->E;
298
299  /* First increment the byte count.  RFC 1321 specifies the possible
300     length of the file up to 2^64 bits.  Here we only compute the
301     number of bytes.  Do a double word increment.  */
302  ctx->total[0] += len;
303  ctx->total[1] += ((len >> 31) >> 1) + (ctx->total[0] < len);
304
305#define rol(x, n) (((x) << (n)) | ((sha1_uint32) (x) >> (32 - (n))))
306
307#define M(I) ( tm =   x[I&0x0f] ^ x[(I-14)&0x0f] \
308		    ^ x[(I-8)&0x0f] ^ x[(I-3)&0x0f] \
309	       , (x[I&0x0f] = rol(tm, 1)) )
310
311#define R(A,B,C,D,E,F,K,M)  do { E += rol( A, 5 )     \
312				      + F( B, C, D )  \
313				      + K	      \
314				      + M;	      \
315				 B = rol( B, 30 );    \
316			       } while(0)
317
318  while (words < endp)
319    {
320      sha1_uint32 tm;
321      int t;
322      for (t = 0; t < 16; t++)
323	{
324	  x[t] = SWAP (*words);
325	  words++;
326	}
327
328      R( a, b, c, d, e, F1, K1, x[ 0] );
329      R( e, a, b, c, d, F1, K1, x[ 1] );
330      R( d, e, a, b, c, F1, K1, x[ 2] );
331      R( c, d, e, a, b, F1, K1, x[ 3] );
332      R( b, c, d, e, a, F1, K1, x[ 4] );
333      R( a, b, c, d, e, F1, K1, x[ 5] );
334      R( e, a, b, c, d, F1, K1, x[ 6] );
335      R( d, e, a, b, c, F1, K1, x[ 7] );
336      R( c, d, e, a, b, F1, K1, x[ 8] );
337      R( b, c, d, e, a, F1, K1, x[ 9] );
338      R( a, b, c, d, e, F1, K1, x[10] );
339      R( e, a, b, c, d, F1, K1, x[11] );
340      R( d, e, a, b, c, F1, K1, x[12] );
341      R( c, d, e, a, b, F1, K1, x[13] );
342      R( b, c, d, e, a, F1, K1, x[14] );
343      R( a, b, c, d, e, F1, K1, x[15] );
344      R( e, a, b, c, d, F1, K1, M(16) );
345      R( d, e, a, b, c, F1, K1, M(17) );
346      R( c, d, e, a, b, F1, K1, M(18) );
347      R( b, c, d, e, a, F1, K1, M(19) );
348      R( a, b, c, d, e, F2, K2, M(20) );
349      R( e, a, b, c, d, F2, K2, M(21) );
350      R( d, e, a, b, c, F2, K2, M(22) );
351      R( c, d, e, a, b, F2, K2, M(23) );
352      R( b, c, d, e, a, F2, K2, M(24) );
353      R( a, b, c, d, e, F2, K2, M(25) );
354      R( e, a, b, c, d, F2, K2, M(26) );
355      R( d, e, a, b, c, F2, K2, M(27) );
356      R( c, d, e, a, b, F2, K2, M(28) );
357      R( b, c, d, e, a, F2, K2, M(29) );
358      R( a, b, c, d, e, F2, K2, M(30) );
359      R( e, a, b, c, d, F2, K2, M(31) );
360      R( d, e, a, b, c, F2, K2, M(32) );
361      R( c, d, e, a, b, F2, K2, M(33) );
362      R( b, c, d, e, a, F2, K2, M(34) );
363      R( a, b, c, d, e, F2, K2, M(35) );
364      R( e, a, b, c, d, F2, K2, M(36) );
365      R( d, e, a, b, c, F2, K2, M(37) );
366      R( c, d, e, a, b, F2, K2, M(38) );
367      R( b, c, d, e, a, F2, K2, M(39) );
368      R( a, b, c, d, e, F3, K3, M(40) );
369      R( e, a, b, c, d, F3, K3, M(41) );
370      R( d, e, a, b, c, F3, K3, M(42) );
371      R( c, d, e, a, b, F3, K3, M(43) );
372      R( b, c, d, e, a, F3, K3, M(44) );
373      R( a, b, c, d, e, F3, K3, M(45) );
374      R( e, a, b, c, d, F3, K3, M(46) );
375      R( d, e, a, b, c, F3, K3, M(47) );
376      R( c, d, e, a, b, F3, K3, M(48) );
377      R( b, c, d, e, a, F3, K3, M(49) );
378      R( a, b, c, d, e, F3, K3, M(50) );
379      R( e, a, b, c, d, F3, K3, M(51) );
380      R( d, e, a, b, c, F3, K3, M(52) );
381      R( c, d, e, a, b, F3, K3, M(53) );
382      R( b, c, d, e, a, F3, K3, M(54) );
383      R( a, b, c, d, e, F3, K3, M(55) );
384      R( e, a, b, c, d, F3, K3, M(56) );
385      R( d, e, a, b, c, F3, K3, M(57) );
386      R( c, d, e, a, b, F3, K3, M(58) );
387      R( b, c, d, e, a, F3, K3, M(59) );
388      R( a, b, c, d, e, F4, K4, M(60) );
389      R( e, a, b, c, d, F4, K4, M(61) );
390      R( d, e, a, b, c, F4, K4, M(62) );
391      R( c, d, e, a, b, F4, K4, M(63) );
392      R( b, c, d, e, a, F4, K4, M(64) );
393      R( a, b, c, d, e, F4, K4, M(65) );
394      R( e, a, b, c, d, F4, K4, M(66) );
395      R( d, e, a, b, c, F4, K4, M(67) );
396      R( c, d, e, a, b, F4, K4, M(68) );
397      R( b, c, d, e, a, F4, K4, M(69) );
398      R( a, b, c, d, e, F4, K4, M(70) );
399      R( e, a, b, c, d, F4, K4, M(71) );
400      R( d, e, a, b, c, F4, K4, M(72) );
401      R( c, d, e, a, b, F4, K4, M(73) );
402      R( b, c, d, e, a, F4, K4, M(74) );
403      R( a, b, c, d, e, F4, K4, M(75) );
404      R( e, a, b, c, d, F4, K4, M(76) );
405      R( d, e, a, b, c, F4, K4, M(77) );
406      R( c, d, e, a, b, F4, K4, M(78) );
407      R( b, c, d, e, a, F4, K4, M(79) );
408
409      a = ctx->A += a;
410      b = ctx->B += b;
411      c = ctx->C += c;
412      d = ctx->D += d;
413      e = ctx->E += e;
414    }
415}
416