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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 | /* Functions to compute SHA256 message digest of files or memory blocks.
according to the definition of SHA256 in FIPS 180-2.
Copyright (C) 2007 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* Written by Ulrich Drepper <drepper@redhat.com>, 2007. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <endian.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include "sha256.h"
#if __BYTE_ORDER == __LITTLE_ENDIAN
# ifdef _LIBC
# include <byteswap.h>
# define SWAP(n) bswap_32 (n)
# else
# define SWAP(n) \
(((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
# endif
#else
# define SWAP(n) (n)
#endif
/* This array contains the bytes used to pad the buffer to the next
64-byte boundary. (FIPS 180-2:5.1.1) */
static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
/* Constants for SHA256 from FIPS 180-2:4.2.2. */
static const uint32_t K[64] =
{
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};
/* Process LEN bytes of BUFFER, accumulating context into CTX.
It is assumed that LEN % 64 == 0. */
static void
sha256_process_block (const void *buffer, size_t len, struct sha256_ctx *ctx)
{
const uint32_t *words = buffer;
size_t nwords = len / sizeof (uint32_t);
uint32_t a = ctx->H[0];
uint32_t b = ctx->H[1];
uint32_t c = ctx->H[2];
uint32_t d = ctx->H[3];
uint32_t e = ctx->H[4];
uint32_t f = ctx->H[5];
uint32_t g = ctx->H[6];
uint32_t h = ctx->H[7];
/* First increment the byte count. FIPS 180-2 specifies the possible
length of the file up to 2^64 bits. Here we only compute the
number of bytes. Do a double word increment. */
ctx->total[0] += len;
if (ctx->total[0] < len)
++ctx->total[1];
/* Process all bytes in the buffer with 64 bytes in each round of
the loop. */
while (nwords > 0)
{
uint32_t W[64];
uint32_t a_save = a;
uint32_t b_save = b;
uint32_t c_save = c;
uint32_t d_save = d;
uint32_t e_save = e;
uint32_t f_save = f;
uint32_t g_save = g;
uint32_t h_save = h;
/* Operators defined in FIPS 180-2:4.1.2. */
#define _Ch(x, y, z) ((x & y) ^ (~x & z))
#define _Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
#define _S0(x) (CYCLIC (x, 2) ^ CYCLIC (x, 13) ^ CYCLIC (x, 22))
#define _S1(x) (CYCLIC (x, 6) ^ CYCLIC (x, 11) ^ CYCLIC (x, 25))
#define _R0(x) (CYCLIC (x, 7) ^ CYCLIC (x, 18) ^ (x >> 3))
#define _R1(x) (CYCLIC (x, 17) ^ CYCLIC (x, 19) ^ (x >> 10))
/* It is unfortunate that C does not provide an operator for
cyclic rotation. Hope the C compiler is smart enough. */
#define CYCLIC(w, s) ((w >> s) | (w << (32 - s)))
/* Compute the message schedule according to FIPS 180-2:6.2.2 step 2. */
for (unsigned int t = 0; t < 16; ++t)
{
W[t] = SWAP (*words);
++words;
}
for (unsigned int t = 16; t < 64; ++t)
W[t] = _R1 (W[t - 2]) + W[t - 7] + _R0 (W[t - 15]) + W[t - 16];
/* The actual computation according to FIPS 180-2:6.2.2 step 3. */
for (unsigned int t = 0; t < 64; ++t)
{
uint32_t T1 = h + _S1 (e) + _Ch (e, f, g) + K[t] + W[t];
uint32_t T2 = _S0 (a) + _Maj (a, b, c);
h = g;
g = f;
f = e;
e = d + T1;
d = c;
c = b;
b = a;
a = T1 + T2;
}
/* Add the starting values of the context according to FIPS 180-2:6.2.2
step 4. */
a += a_save;
b += b_save;
c += c_save;
d += d_save;
e += e_save;
f += f_save;
g += g_save;
h += h_save;
/* Prepare for the next round. */
nwords -= 16;
}
/* Put checksum in context given as argument. */
ctx->H[0] = a;
ctx->H[1] = b;
ctx->H[2] = c;
ctx->H[3] = d;
ctx->H[4] = e;
ctx->H[5] = f;
ctx->H[6] = g;
ctx->H[7] = h;
}
/* Initialize structure containing state of computation.
(FIPS 180-2:5.3.2) */
void
__sha256_init_ctx (struct sha256_ctx *ctx)
{
ctx->H[0] = 0x6a09e667;
ctx->H[1] = 0xbb67ae85;
ctx->H[2] = 0x3c6ef372;
ctx->H[3] = 0xa54ff53a;
ctx->H[4] = 0x510e527f;
ctx->H[5] = 0x9b05688c;
ctx->H[6] = 0x1f83d9ab;
ctx->H[7] = 0x5be0cd19;
ctx->total[0] = ctx->total[1] = 0;
ctx->buflen = 0;
}
/* Process the remaining bytes in the internal buffer and the usual
prolog according to the standard and write the result to RESBUF.
IMPORTANT: On some systems it is required that RESBUF is correctly
aligned for a 32 bits value. */
void *
__sha256_finish_ctx (struct sha256_ctx *ctx, void *resbuf)
{
/* Take yet unprocessed bytes into account. */
uint32_t bytes = ctx->buflen;
size_t pad;
/* Now count remaining bytes. */
ctx->total[0] += bytes;
if (ctx->total[0] < bytes)
++ctx->total[1];
pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
memcpy (&ctx->buffer[bytes], fillbuf, pad);
/* Put the 64-bit file length in *bits* at the end of the buffer. */
*(uint32_t *) &ctx->buffer[bytes + pad + 4] = SWAP (ctx->total[0] << 3);
*(uint32_t *) &ctx->buffer[bytes + pad] = SWAP ((ctx->total[1] << 3) |
(ctx->total[0] >> 29));
/* Process last bytes. */
sha256_process_block (ctx->buffer, bytes + pad + 8, ctx);
/* Put result from CTX in first 32 bytes following RESBUF. */
for (unsigned int i = 0; i < 8; ++i)
((uint32_t *) resbuf)[i] = SWAP (ctx->H[i]);
return resbuf;
}
void
__sha256_process_bytes (const void *buffer, size_t len, struct sha256_ctx *ctx)
{
/* When we already have some bits in our internal buffer concatenate
both inputs first. */
if (ctx->buflen != 0)
{
size_t left_over = ctx->buflen;
size_t add = 128 - left_over > len ? len : 128 - left_over;
memcpy (&ctx->buffer[left_over], buffer, add);
ctx->buflen += add;
if (ctx->buflen > 64)
{
sha256_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
ctx->buflen &= 63;
/* The regions in the following copy operation cannot overlap. */
memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
ctx->buflen);
}
buffer = (const char *) buffer + add;
len -= add;
}
/* Process available complete blocks. */
if (len >= 64)
{
#if __GNUC__ >= 2
# define UNALIGNED_P(p) (((uintptr_t) p) % __alignof__ (uint32_t) != 0)
#else
# define UNALIGNED_P(p) (((uintptr_t) p) % sizeof (uint32_t) != 0)
#endif
if (UNALIGNED_P (buffer))
while (len > 64)
{
sha256_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
buffer = (const char *) buffer + 64;
len -= 64;
}
else
{
sha256_process_block (buffer, len & ~63, ctx);
buffer = (const char *) buffer + (len & ~63);
len &= 63;
}
}
/* Move remaining bytes into internal buffer. */
if (len > 0)
{
size_t left_over = ctx->buflen;
memcpy (&ctx->buffer[left_over], buffer, len);
left_over += len;
if (left_over >= 64)
{
sha256_process_block (ctx->buffer, 64, ctx);
left_over -= 64;
memcpy (ctx->buffer, &ctx->buffer[64], left_over);
}
ctx->buflen = left_over;
}
}
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