1 /* sha256.c - Functions to compute SHA256 and SHA224 message digest of files or
2 memory blocks according to the NIST specification FIPS-180-2.
4 Copyright (C) 2005, 2006, 2008 Free Software Foundation, Inc.
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
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.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 /* Written by David Madore, considerably copypasting from
20 Scott G. Miller's sha1.c
29 #include "unlocked-io.h"
32 #ifdef WORDS_BIGENDIAN
36 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
39 #define BLOCKSIZE 4096
40 #if BLOCKSIZE % 64 != 0
41 #error "invalid BLOCKSIZE"
44 /* This array contains the bytes used to pad the buffer to the next
46 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
49 Takes a pointer to a 256 bit block of data (eight 32 bit ints) and
50 intializes it to the start constants of the SHA256 algorithm. This
51 must be called before using hash in the call to sha256_hash
53 void sha256_init_ctx(struct sha256_ctx *ctx)
55 ctx->state[0] = 0x6a09e667UL;
56 ctx->state[1] = 0xbb67ae85UL;
57 ctx->state[2] = 0x3c6ef372UL;
58 ctx->state[3] = 0xa54ff53aUL;
59 ctx->state[4] = 0x510e527fUL;
60 ctx->state[5] = 0x9b05688cUL;
61 ctx->state[6] = 0x1f83d9abUL;
62 ctx->state[7] = 0x5be0cd19UL;
64 ctx->total[0] = ctx->total[1] = 0;
68 void sha224_init_ctx(struct sha256_ctx *ctx)
70 ctx->state[0] = 0xc1059ed8UL;
71 ctx->state[1] = 0x367cd507UL;
72 ctx->state[2] = 0x3070dd17UL;
73 ctx->state[3] = 0xf70e5939UL;
74 ctx->state[4] = 0xffc00b31UL;
75 ctx->state[5] = 0x68581511UL;
76 ctx->state[6] = 0x64f98fa7UL;
77 ctx->state[7] = 0xbefa4fa4UL;
79 ctx->total[0] = ctx->total[1] = 0;
83 /* Copy the value from v into the memory location pointed to by *cp,
84 If your architecture allows unaligned access this is equivalent to
85 * (uint32_t *) cp = v */
86 static inline void set_uint32(char *cp, uint32_t v)
88 memcpy(cp, &v, sizeof v);
91 /* Put result from CTX in first 32 bytes following RESBUF. The result
92 must be in little endian byte order. */
93 void *sha256_read_ctx(const struct sha256_ctx *ctx, void *resbuf)
98 for (i = 0; i < 8; i++)
99 set_uint32(r + i * sizeof ctx->state[0], SWAP(ctx->state[i]));
104 void *sha224_read_ctx(const struct sha256_ctx *ctx, void *resbuf)
109 for (i = 0; i < 7; i++)
110 set_uint32(r + i * sizeof ctx->state[0], SWAP(ctx->state[i]));
115 /* Process the remaining bytes in the internal buffer and the usual
116 prolog according to the standard and write the result to RESBUF. */
117 static void sha256_conclude_ctx(struct sha256_ctx *ctx)
119 /* Take yet unprocessed bytes into account. */
120 size_t bytes = ctx->buflen;
121 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
123 /* Now count remaining bytes. */
124 ctx->total[0] += bytes;
125 if (ctx->total[0] < bytes)
128 /* Put the 64-bit file length in *bits* at the end of the buffer.
129 Use set_uint32 rather than a simple assignment, to avoid risk of
131 set_uint32((char *)&ctx->buffer[size - 2],
132 SWAP((ctx->total[1] << 3) | (ctx->total[0] >> 29)));
133 set_uint32((char *)&ctx->buffer[size - 1], SWAP(ctx->total[0] << 3));
135 memcpy(&((char *)ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
137 /* Process last bytes. */
138 sha256_process_block(ctx->buffer, size * 4, ctx);
141 void *sha256_finish_ctx(struct sha256_ctx *ctx, void *resbuf)
143 sha256_conclude_ctx(ctx);
144 return sha256_read_ctx(ctx, resbuf);
147 void *sha224_finish_ctx(struct sha256_ctx *ctx, void *resbuf)
149 sha256_conclude_ctx(ctx);
150 return sha224_read_ctx(ctx, resbuf);
153 /* Compute SHA256 message digest for bytes read from STREAM. The
154 resulting message digest number will be written into the 32 bytes
155 beginning at RESBLOCK. */
156 int sha256_stream(FILE * stream, void *resblock)
158 struct sha256_ctx ctx;
159 char buffer[BLOCKSIZE + 72];
162 /* Initialize the computation context. */
163 sha256_init_ctx(&ctx);
165 /* Iterate over full file contents. */
167 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
168 computation function processes the whole buffer so that with the
169 next round of the loop another block can be read. */
173 /* Read block. Take care for partial reads. */
175 n = fread(buffer + sum, 1, BLOCKSIZE - sum, stream);
179 if (sum == BLOCKSIZE)
183 /* Check for the error flag IFF N == 0, so that we don't
184 exit the loop after a partial read due to e.g., EAGAIN
188 goto process_partial_block;
191 /* We've read at least one byte, so ignore errors. But always
192 check for EOF, since feof may be true even though N > 0.
193 Otherwise, we could end up calling fread after EOF. */
195 goto process_partial_block;
198 /* Process buffer with BLOCKSIZE bytes. Note that
201 sha256_process_block(buffer, BLOCKSIZE, &ctx);
204 process_partial_block:;
206 /* Process any remaining bytes. */
208 sha256_process_bytes(buffer, sum, &ctx);
210 /* Construct result in desired memory. */
211 sha256_finish_ctx(&ctx, resblock);
215 /* FIXME: Avoid code duplication */
216 int sha224_stream(FILE * stream, void *resblock)
218 struct sha256_ctx ctx;
219 char buffer[BLOCKSIZE + 72];
222 /* Initialize the computation context. */
223 sha224_init_ctx(&ctx);
225 /* Iterate over full file contents. */
227 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
228 computation function processes the whole buffer so that with the
229 next round of the loop another block can be read. */
233 /* Read block. Take care for partial reads. */
235 n = fread(buffer + sum, 1, BLOCKSIZE - sum, stream);
239 if (sum == BLOCKSIZE)
243 /* Check for the error flag IFF N == 0, so that we don't
244 exit the loop after a partial read due to e.g., EAGAIN
248 goto process_partial_block;
251 /* We've read at least one byte, so ignore errors. But always
252 check for EOF, since feof may be true even though N > 0.
253 Otherwise, we could end up calling fread after EOF. */
255 goto process_partial_block;
258 /* Process buffer with BLOCKSIZE bytes. Note that
261 sha256_process_block(buffer, BLOCKSIZE, &ctx);
264 process_partial_block:;
266 /* Process any remaining bytes. */
268 sha256_process_bytes(buffer, sum, &ctx);
270 /* Construct result in desired memory. */
271 sha224_finish_ctx(&ctx, resblock);
275 /* Compute SHA512 message digest for LEN bytes beginning at BUFFER. The
276 result is always in little endian byte order, so that a byte-wise
277 output yields to the wanted ASCII representation of the message
279 void *sha256_buffer(const char *buffer, size_t len, void *resblock)
281 struct sha256_ctx ctx;
283 /* Initialize the computation context. */
284 sha256_init_ctx(&ctx);
286 /* Process whole buffer but last len % 64 bytes. */
287 sha256_process_bytes(buffer, len, &ctx);
289 /* Put result in desired memory area. */
290 return sha256_finish_ctx(&ctx, resblock);
293 void *sha224_buffer(const char *buffer, size_t len, void *resblock)
295 struct sha256_ctx ctx;
297 /* Initialize the computation context. */
298 sha224_init_ctx(&ctx);
300 /* Process whole buffer but last len % 64 bytes. */
301 sha256_process_bytes(buffer, len, &ctx);
303 /* Put result in desired memory area. */
304 return sha224_finish_ctx(&ctx, resblock);
308 sha256_process_bytes(const void *buffer, size_t len, struct sha256_ctx *ctx)
310 /* When we already have some bits in our internal buffer concatenate
311 both inputs first. */
312 if (ctx->buflen != 0) {
313 size_t left_over = ctx->buflen;
314 size_t add = 128 - left_over > len ? len : 128 - left_over;
316 memcpy(&((char *)ctx->buffer)[left_over], buffer, add);
319 if (ctx->buflen > 64) {
320 sha256_process_block(ctx->buffer, ctx->buflen & ~63,
324 /* The regions in the following copy operation cannot overlap. */
326 &((char *)ctx->buffer)[(left_over + add) & ~63],
330 buffer = (const char *)buffer + add;
334 /* Process available complete blocks. */
336 #if !_STRING_ARCH_unaligned
337 #define alignof(type) offsetof (struct { char c; type x; }, x)
338 #define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0)
339 if (UNALIGNED_P(buffer))
341 sha256_process_block(memcpy
342 (ctx->buffer, buffer, 64),
344 buffer = (const char *)buffer + 64;
349 sha256_process_block(buffer, len & ~63, ctx);
350 buffer = (const char *)buffer + (len & ~63);
355 /* Move remaining bytes in internal buffer. */
357 size_t left_over = ctx->buflen;
359 memcpy(&((char *)ctx->buffer)[left_over], buffer, len);
361 if (left_over >= 64) {
362 sha256_process_block(ctx->buffer, 64, ctx);
364 memcpy(ctx->buffer, &ctx->buffer[16], left_over);
366 ctx->buflen = left_over;
370 /* --- Code below is the primary difference between sha1.c and sha256.c --- */
372 /* SHA256 round constants */
373 #define K(I) sha256_round_constants[I]
374 static const uint32_t sha256_round_constants[64] = {
375 0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL,
376 0x3956c25bUL, 0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL,
377 0xd807aa98UL, 0x12835b01UL, 0x243185beUL, 0x550c7dc3UL,
378 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL, 0xc19bf174UL,
379 0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
380 0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL,
381 0x983e5152UL, 0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL,
382 0xc6e00bf3UL, 0xd5a79147UL, 0x06ca6351UL, 0x14292967UL,
383 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL, 0x53380d13UL,
384 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
385 0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL,
386 0xd192e819UL, 0xd6990624UL, 0xf40e3585UL, 0x106aa070UL,
387 0x19a4c116UL, 0x1e376c08UL, 0x2748774cUL, 0x34b0bcb5UL,
388 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL, 0x682e6ff3UL,
389 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
390 0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL,
393 /* Round functions. */
394 #define F2(A,B,C) ( ( A & B ) | ( C & ( A | B ) ) )
395 #define F1(E,F,G) ( G ^ ( E & ( F ^ G ) ) )
397 /* Process LEN bytes of BUFFER, accumulating context into CTX.
398 It is assumed that LEN % 64 == 0.
399 Most of this code comes from GnuPG's cipher/sha1.c. */
402 sha256_process_block(const void *buffer, size_t len, struct sha256_ctx *ctx)
404 const uint32_t *words = buffer;
405 size_t nwords = len / sizeof(uint32_t);
406 const uint32_t *endp = words + nwords;
408 uint32_t a = ctx->state[0];
409 uint32_t b = ctx->state[1];
410 uint32_t c = ctx->state[2];
411 uint32_t d = ctx->state[3];
412 uint32_t e = ctx->state[4];
413 uint32_t f = ctx->state[5];
414 uint32_t g = ctx->state[6];
415 uint32_t h = ctx->state[7];
417 /* First increment the byte count. FIPS PUB 180-2 specifies the possible
418 length of the file up to 2^64 bits. Here we only compute the
419 number of bytes. Do a double word increment. */
420 ctx->total[0] += len;
421 if (ctx->total[0] < len)
424 #define rol(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
425 #define S0(x) (rol(x,25)^rol(x,14)^(x>>3))
426 #define S1(x) (rol(x,15)^rol(x,13)^(x>>10))
427 #define SS0(x) (rol(x,30)^rol(x,19)^rol(x,10))
428 #define SS1(x) (rol(x,26)^rol(x,21)^rol(x,7))
430 #define M(I) ( tm = S1(x[(I-2)&0x0f]) + x[(I-7)&0x0f] \
431 + S0(x[(I-15)&0x0f]) + x[I&0x0f] \
434 #define R(A,B,C,D,E,F,G,H,K,M) do { t0 = SS0(A) + F2(A,B,C); \
439 D += t1; H = t0 + t1; \
442 while (words < endp) {
446 /* FIXME: see sha1.c for a better implementation. */
447 for (t = 0; t < 16; t++) {
452 R(a, b, c, d, e, f, g, h, K(0), x[0]);
453 R(h, a, b, c, d, e, f, g, K(1), x[1]);
454 R(g, h, a, b, c, d, e, f, K(2), x[2]);
455 R(f, g, h, a, b, c, d, e, K(3), x[3]);
456 R(e, f, g, h, a, b, c, d, K(4), x[4]);
457 R(d, e, f, g, h, a, b, c, K(5), x[5]);
458 R(c, d, e, f, g, h, a, b, K(6), x[6]);
459 R(b, c, d, e, f, g, h, a, K(7), x[7]);
460 R(a, b, c, d, e, f, g, h, K(8), x[8]);
461 R(h, a, b, c, d, e, f, g, K(9), x[9]);
462 R(g, h, a, b, c, d, e, f, K(10), x[10]);
463 R(f, g, h, a, b, c, d, e, K(11), x[11]);
464 R(e, f, g, h, a, b, c, d, K(12), x[12]);
465 R(d, e, f, g, h, a, b, c, K(13), x[13]);
466 R(c, d, e, f, g, h, a, b, K(14), x[14]);
467 R(b, c, d, e, f, g, h, a, K(15), x[15]);
468 R(a, b, c, d, e, f, g, h, K(16), M(16));
469 R(h, a, b, c, d, e, f, g, K(17), M(17));
470 R(g, h, a, b, c, d, e, f, K(18), M(18));
471 R(f, g, h, a, b, c, d, e, K(19), M(19));
472 R(e, f, g, h, a, b, c, d, K(20), M(20));
473 R(d, e, f, g, h, a, b, c, K(21), M(21));
474 R(c, d, e, f, g, h, a, b, K(22), M(22));
475 R(b, c, d, e, f, g, h, a, K(23), M(23));
476 R(a, b, c, d, e, f, g, h, K(24), M(24));
477 R(h, a, b, c, d, e, f, g, K(25), M(25));
478 R(g, h, a, b, c, d, e, f, K(26), M(26));
479 R(f, g, h, a, b, c, d, e, K(27), M(27));
480 R(e, f, g, h, a, b, c, d, K(28), M(28));
481 R(d, e, f, g, h, a, b, c, K(29), M(29));
482 R(c, d, e, f, g, h, a, b, K(30), M(30));
483 R(b, c, d, e, f, g, h, a, K(31), M(31));
484 R(a, b, c, d, e, f, g, h, K(32), M(32));
485 R(h, a, b, c, d, e, f, g, K(33), M(33));
486 R(g, h, a, b, c, d, e, f, K(34), M(34));
487 R(f, g, h, a, b, c, d, e, K(35), M(35));
488 R(e, f, g, h, a, b, c, d, K(36), M(36));
489 R(d, e, f, g, h, a, b, c, K(37), M(37));
490 R(c, d, e, f, g, h, a, b, K(38), M(38));
491 R(b, c, d, e, f, g, h, a, K(39), M(39));
492 R(a, b, c, d, e, f, g, h, K(40), M(40));
493 R(h, a, b, c, d, e, f, g, K(41), M(41));
494 R(g, h, a, b, c, d, e, f, K(42), M(42));
495 R(f, g, h, a, b, c, d, e, K(43), M(43));
496 R(e, f, g, h, a, b, c, d, K(44), M(44));
497 R(d, e, f, g, h, a, b, c, K(45), M(45));
498 R(c, d, e, f, g, h, a, b, K(46), M(46));
499 R(b, c, d, e, f, g, h, a, K(47), M(47));
500 R(a, b, c, d, e, f, g, h, K(48), M(48));
501 R(h, a, b, c, d, e, f, g, K(49), M(49));
502 R(g, h, a, b, c, d, e, f, K(50), M(50));
503 R(f, g, h, a, b, c, d, e, K(51), M(51));
504 R(e, f, g, h, a, b, c, d, K(52), M(52));
505 R(d, e, f, g, h, a, b, c, K(53), M(53));
506 R(c, d, e, f, g, h, a, b, K(54), M(54));
507 R(b, c, d, e, f, g, h, a, K(55), M(55));
508 R(a, b, c, d, e, f, g, h, K(56), M(56));
509 R(h, a, b, c, d, e, f, g, K(57), M(57));
510 R(g, h, a, b, c, d, e, f, K(58), M(58));
511 R(f, g, h, a, b, c, d, e, K(59), M(59));
512 R(e, f, g, h, a, b, c, d, K(60), M(60));
513 R(d, e, f, g, h, a, b, c, K(61), M(61));
514 R(c, d, e, f, g, h, a, b, K(62), M(62));
515 R(b, c, d, e, f, g, h, a, K(63), M(63));
517 a = ctx->state[0] += a;
518 b = ctx->state[1] += b;
519 c = ctx->state[2] += c;
520 d = ctx->state[3] += d;
521 e = ctx->state[4] += e;
522 f = ctx->state[5] += f;
523 g = ctx->state[6] += g;
524 h = ctx->state[7] += h;