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)  */
51 static 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.  */
57 void
sha1_init_ctx(struct sha1_ctx * ctx)58 sha1_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.  */
75 void *
sha1_read_ctx(const struct sha1_ctx * ctx,void * resbuf)76 sha1_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.  */
92 void *
sha1_finish_ctx(struct sha1_ctx * ctx,void * resbuf)93 sha1_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.  */
119 int
sha1_stream(FILE * stream,void * resblock)120 sha1_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.  */
186 void *
sha1_buffer(const char * buffer,size_t len,void * resblock)187 sha1_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 
201 void
sha1_process_bytes(const void * buffer,size_t len,struct sha1_ctx * ctx)202 sha1_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 
286 void
sha1_process_block(const void * buffer,size_t len,struct sha1_ctx * ctx)287 sha1_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