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) 2000-2023 Free Software Foundation, Inc.
5
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
9 later version.
10
11 This program 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
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software Foundation,
18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
19
20 /* Written by Scott G. Miller
21 Credits:
22 Robert Klep <robert@ilse.nl> -- Expansion function fix
23 */
24
25 #include <config.h>
26
27 #include "sha1.h"
28
29 #include <stddef.h>
30 #include <string.h>
31
32 #if USE_UNLOCKED_IO
33 # include "unlocked-io.h"
34 #endif
35
36 #ifdef WORDS_BIGENDIAN
37 # define SWAP(n) (n)
38 #else
39 # define SWAP(n) \
40 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
41 #endif
42
43 #define BLOCKSIZE 4096
44 #if BLOCKSIZE % 64 != 0
45 # error "invalid BLOCKSIZE"
46 #endif
47
48 /* This array contains the bytes used to pad the buffer to the next
49 64-byte boundary. (RFC 1321, 3.1: Step 1) */
50 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
51
52
53 /* Take a pointer to a 160 bit block of data (five 32 bit ints) and
54 initialize it to the start constants of the SHA1 algorithm. This
55 must be called before using hash in the call to sha1_hash. */
56 void
57 sha1_init_ctx (struct sha1_ctx *ctx)
58 {
59 ctx->A = 0x67452301;
60 ctx->B = 0xefcdab89;
61 ctx->C = 0x98badcfe;
62 ctx->D = 0x10325476;
63 ctx->E = 0xc3d2e1f0;
64
65 ctx->total[0] = ctx->total[1] = 0;
66 ctx->buflen = 0;
67 }
68
69 /* Put result from CTX in first 20 bytes following RESBUF. The result
70 must be in little endian byte order.
71
72 IMPORTANT: On some systems it is required that RESBUF is correctly
73 aligned for a 32-bit value. */
74 void *
75 sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf)
76 {
77 ((sha1_uint32 *) resbuf)[0] = SWAP (ctx->A);
78 ((sha1_uint32 *) resbuf)[1] = SWAP (ctx->B);
79 ((sha1_uint32 *) resbuf)[2] = SWAP (ctx->C);
80 ((sha1_uint32 *) resbuf)[3] = SWAP (ctx->D);
81 ((sha1_uint32 *) resbuf)[4] = SWAP (ctx->E);
82
83 return resbuf;
84 }
85
86 /* Process the remaining bytes in the internal buffer and the usual
87 prolog according to the standard and write the result to RESBUF.
88
89 IMPORTANT: On some systems it is required that RESBUF is correctly
90 aligned for a 32-bit value. */
91 void *
92 sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf)
93 {
94 /* Take yet unprocessed bytes into account. */
95 sha1_uint32 bytes = ctx->buflen;
96 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
97
98 /* Now count remaining bytes. */
99 ctx->total[0] += bytes;
100 if (ctx->total[0] < bytes)
101 ++ctx->total[1];
102
103 /* Put the 64-bit file length in *bits* at the end of the buffer. */
104 ctx->buffer[size - 2] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
105 ctx->buffer[size - 1] = SWAP (ctx->total[0] << 3);
106
107 memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
108
109 /* Process last bytes. */
110 sha1_process_block (ctx->buffer, size * 4, ctx);
111
112 return sha1_read_ctx (ctx, resbuf);
113 }
114
115 /* Compute SHA1 message digest for bytes read from STREAM. The
116 resulting message digest number will be written into the 16 bytes
117 beginning at RESBLOCK. */
118 int
119 sha1_stream (FILE *stream, void *resblock)
120 {
121 struct sha1_ctx ctx;
122 char buffer[BLOCKSIZE + 72];
123 size_t sum;
124
125 /* Initialize the computation context. */
126 sha1_init_ctx (&ctx);
127
128 /* Iterate over full file contents. */
129 while (1)
130 {
131 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
132 computation function processes the whole buffer so that with the
133 next round of the loop another block can be read. */
134 size_t n;
135 sum = 0;
136
137 /* Read block. Take care for partial reads. */
138 while (1)
139 {
140 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
141
142 sum += n;
143
144 if (sum == BLOCKSIZE)
145 break;
146
147 if (n == 0)
148 {
149 /* Check for the error flag IFF N == 0, so that we don't
150 exit the loop after a partial read due to e.g., EAGAIN
151 or EWOULDBLOCK. */
152 if (ferror (stream))
153 return 1;
154 goto process_partial_block;
155 }
156
157 /* We've read at least one byte, so ignore errors. But always
158 check for EOF, since feof may be true even though N > 0.
159 Otherwise, we could end up calling fread after EOF. */
160 if (feof (stream))
161 goto process_partial_block;
162 }
163
164 /* Process buffer with BLOCKSIZE bytes. Note that
165 BLOCKSIZE % 64 == 0
166 */
167 sha1_process_block (buffer, BLOCKSIZE, &ctx);
168 }
169
170 process_partial_block:;
171
172 /* Process any remaining bytes. */
173 if (sum > 0)
174 sha1_process_bytes (buffer, sum, &ctx);
175
176 /* Construct result in desired memory. */
177 sha1_finish_ctx (&ctx, resblock);
178 return 0;
179 }
180
181 /* Compute SHA1 message digest for LEN bytes beginning at BUFFER. The
182 result is always in little endian byte order, so that a byte-wise
183 output yields to the wanted ASCII representation of the message
184 digest. */
185 void *
186 sha1_buffer (const char *buffer, size_t len, void *resblock)
187 {
188 struct sha1_ctx ctx;
189
190 /* Initialize the computation context. */
191 sha1_init_ctx (&ctx);
192
193 /* Process whole buffer but last len % 64 bytes. */
194 sha1_process_bytes (buffer, len, &ctx);
195
196 /* Put result in desired memory area. */
197 return sha1_finish_ctx (&ctx, resblock);
198 }
199
200 void
201 sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx)
202 {
203 /* When we already have some bits in our internal buffer concatenate
204 both inputs first. */
205 if (ctx->buflen != 0)
206 {
207 size_t left_over = ctx->buflen;
208 size_t add = 128 - left_over > len ? len : 128 - left_over;
209
210 memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
211 ctx->buflen += add;
212
213 if (ctx->buflen > 64)
214 {
215 sha1_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
216
217 ctx->buflen &= 63;
218 /* The regions in the following copy operation cannot overlap. */
219 memcpy (ctx->buffer,
220 &((char *) ctx->buffer)[(left_over + add) & ~63],
221 ctx->buflen);
222 }
223
224 buffer = (const char *) buffer + add;
225 len -= add;
226 }
227
228 /* Process available complete blocks. */
229 if (len >= 64)
230 {
231 #if !_STRING_ARCH_unaligned
232 # define alignof(type) offsetof (struct { char c; type x; }, x)
233 # define UNALIGNED_P(p) (((size_t) p) % alignof (sha1_uint32) != 0)
234 if (UNALIGNED_P (buffer))
235 while (len > 64)
236 {
237 sha1_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
238 buffer = (const char *) buffer + 64;
239 len -= 64;
240 }
241 else
242 #endif
243 {
244 sha1_process_block (buffer, len & ~63, ctx);
245 buffer = (const char *) buffer + (len & ~63);
246 len &= 63;
247 }
248 }
249
250 /* Move remaining bytes in internal buffer. */
251 if (len > 0)
252 {
253 size_t left_over = ctx->buflen;
254
255 memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
256 left_over += len;
257 if (left_over >= 64)
258 {
259 sha1_process_block (ctx->buffer, 64, ctx);
260 left_over -= 64;
261 memmove (ctx->buffer, &ctx->buffer[16], left_over);
262 }
263 ctx->buflen = left_over;
264 }
265 }
266
267 /* --- Code below is the primary difference between md5.c and sha1.c --- */
268
269 /* SHA1 round constants */
270 #define K1 0x5a827999
271 #define K2 0x6ed9eba1
272 #define K3 0x8f1bbcdc
273 #define K4 0xca62c1d6
274
275 /* Round functions. Note that F2 is the same as F4. */
276 #define F1(B,C,D) ( D ^ ( B & ( C ^ D ) ) )
277 #define F2(B,C,D) (B ^ C ^ D)
278 #define F3(B,C,D) ( ( B & C ) | ( D & ( B | C ) ) )
279 #define F4(B,C,D) (B ^ C ^ D)
280
281 /* Process LEN bytes of BUFFER, accumulating context into CTX.
282 It is assumed that LEN % 64 == 0.
283 Most of this code comes from GnuPG's cipher/sha1.c. */
284
285 void
286 sha1_process_block (const void *buffer, size_t len, struct sha1_ctx *ctx)
287 {
288 const sha1_uint32 *words = (const sha1_uint32*) buffer;
289 size_t nwords = len / sizeof (sha1_uint32);
290 const sha1_uint32 *endp = words + nwords;
291 sha1_uint32 x[16];
292 sha1_uint32 a = ctx->A;
293 sha1_uint32 b = ctx->B;
294 sha1_uint32 c = ctx->C;
295 sha1_uint32 d = ctx->D;
296 sha1_uint32 e = ctx->E;
297
298 /* First increment the byte count. RFC 1321 specifies the possible
299 length of the file up to 2^64 bits. Here we only compute the
300 number of bytes. Do a double word increment. */
301 ctx->total[0] += len;
302 ctx->total[1] += ((len >> 31) >> 1) + (ctx->total[0] < len);
303
304 #define rol(x, n) (((x) << (n)) | ((sha1_uint32) (x) >> (32 - (n))))
305
306 #define M(I) ( tm = x[I&0x0f] ^ x[(I-14)&0x0f] \
307 ^ x[(I-8)&0x0f] ^ x[(I-3)&0x0f] \
308 , (x[I&0x0f] = rol(tm, 1)) )
309
310 #define R(A,B,C,D,E,F,K,M) do { E += rol( A, 5 ) \
311 + F( B, C, D ) \
312 + K \
313 + M; \
314 B = rol( B, 30 ); \
315 } while(0)
316
317 while (words < endp)
318 {
319 sha1_uint32 tm;
320 int t;
321 for (t = 0; t < 16; t++)
322 {
323 x[t] = SWAP (*words);
324 words++;
325 }
326
327 R( a, b, c, d, e, F1, K1, x[ 0] );
328 R( e, a, b, c, d, F1, K1, x[ 1] );
329 R( d, e, a, b, c, F1, K1, x[ 2] );
330 R( c, d, e, a, b, F1, K1, x[ 3] );
331 R( b, c, d, e, a, F1, K1, x[ 4] );
332 R( a, b, c, d, e, F1, K1, x[ 5] );
333 R( e, a, b, c, d, F1, K1, x[ 6] );
334 R( d, e, a, b, c, F1, K1, x[ 7] );
335 R( c, d, e, a, b, F1, K1, x[ 8] );
336 R( b, c, d, e, a, F1, K1, x[ 9] );
337 R( a, b, c, d, e, F1, K1, x[10] );
338 R( e, a, b, c, d, F1, K1, x[11] );
339 R( d, e, a, b, c, F1, K1, x[12] );
340 R( c, d, e, a, b, F1, K1, x[13] );
341 R( b, c, d, e, a, F1, K1, x[14] );
342 R( a, b, c, d, e, F1, K1, x[15] );
343 R( e, a, b, c, d, F1, K1, M(16) );
344 R( d, e, a, b, c, F1, K1, M(17) );
345 R( c, d, e, a, b, F1, K1, M(18) );
346 R( b, c, d, e, a, F1, K1, M(19) );
347 R( a, b, c, d, e, F2, K2, M(20) );
348 R( e, a, b, c, d, F2, K2, M(21) );
349 R( d, e, a, b, c, F2, K2, M(22) );
350 R( c, d, e, a, b, F2, K2, M(23) );
351 R( b, c, d, e, a, F2, K2, M(24) );
352 R( a, b, c, d, e, F2, K2, M(25) );
353 R( e, a, b, c, d, F2, K2, M(26) );
354 R( d, e, a, b, c, F2, K2, M(27) );
355 R( c, d, e, a, b, F2, K2, M(28) );
356 R( b, c, d, e, a, F2, K2, M(29) );
357 R( a, b, c, d, e, F2, K2, M(30) );
358 R( e, a, b, c, d, F2, K2, M(31) );
359 R( d, e, a, b, c, F2, K2, M(32) );
360 R( c, d, e, a, b, F2, K2, M(33) );
361 R( b, c, d, e, a, F2, K2, M(34) );
362 R( a, b, c, d, e, F2, K2, M(35) );
363 R( e, a, b, c, d, F2, K2, M(36) );
364 R( d, e, a, b, c, F2, K2, M(37) );
365 R( c, d, e, a, b, F2, K2, M(38) );
366 R( b, c, d, e, a, F2, K2, M(39) );
367 R( a, b, c, d, e, F3, K3, M(40) );
368 R( e, a, b, c, d, F3, K3, M(41) );
369 R( d, e, a, b, c, F3, K3, M(42) );
370 R( c, d, e, a, b, F3, K3, M(43) );
371 R( b, c, d, e, a, F3, K3, M(44) );
372 R( a, b, c, d, e, F3, K3, M(45) );
373 R( e, a, b, c, d, F3, K3, M(46) );
374 R( d, e, a, b, c, F3, K3, M(47) );
375 R( c, d, e, a, b, F3, K3, M(48) );
376 R( b, c, d, e, a, F3, K3, M(49) );
377 R( a, b, c, d, e, F3, K3, M(50) );
378 R( e, a, b, c, d, F3, K3, M(51) );
379 R( d, e, a, b, c, F3, K3, M(52) );
380 R( c, d, e, a, b, F3, K3, M(53) );
381 R( b, c, d, e, a, F3, K3, M(54) );
382 R( a, b, c, d, e, F3, K3, M(55) );
383 R( e, a, b, c, d, F3, K3, M(56) );
384 R( d, e, a, b, c, F3, K3, M(57) );
385 R( c, d, e, a, b, F3, K3, M(58) );
386 R( b, c, d, e, a, F3, K3, M(59) );
387 R( a, b, c, d, e, F4, K4, M(60) );
388 R( e, a, b, c, d, F4, K4, M(61) );
389 R( d, e, a, b, c, F4, K4, M(62) );
390 R( c, d, e, a, b, F4, K4, M(63) );
391 R( b, c, d, e, a, F4, K4, M(64) );
392 R( a, b, c, d, e, F4, K4, M(65) );
393 R( e, a, b, c, d, F4, K4, M(66) );
394 R( d, e, a, b, c, F4, K4, M(67) );
395 R( c, d, e, a, b, F4, K4, M(68) );
396 R( b, c, d, e, a, F4, K4, M(69) );
397 R( a, b, c, d, e, F4, K4, M(70) );
398 R( e, a, b, c, d, F4, K4, M(71) );
399 R( d, e, a, b, c, F4, K4, M(72) );
400 R( c, d, e, a, b, F4, K4, M(73) );
401 R( b, c, d, e, a, F4, K4, M(74) );
402 R( a, b, c, d, e, F4, K4, M(75) );
403 R( e, a, b, c, d, F4, K4, M(76) );
404 R( d, e, a, b, c, F4, K4, M(77) );
405 R( c, d, e, a, b, F4, K4, M(78) );
406 R( b, c, d, e, a, F4, K4, M(79) );
407
408 a = ctx->A += a;
409 b = ctx->B += b;
410 c = ctx->C += c;
411 d = ctx->D += d;
412 e = ctx->E += e;
413 }
414 }