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/**
* libsha2 – SHA-2-family hashing library
*
* Copyright © 2015 Mattias Andrée (maandree@member.fsf.org)
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "digest.h"
#include <alloca.h>
#include <string.h>
/**
* Unified implementation (what can unified without performance impact)
* of the chunk processing for all SHA-2 functions
*
* @param A Wordsize-dependent constant, take a look at the code
* @param B Wordsize-dependent constant, take a look at the code
* @param C Wordsize-dependent constant, take a look at the code
* @param D Wordsize-dependent constant, take a look at the code
* @param E Wordsize-dependent constant, take a look at the code
* @param F Wordsize-dependent constant, take a look at the code
* @param G Wordsize-dependent constant, take a look at the code
* @param H Wordsize-dependent constant, take a look at the code
* @param I Wordsize-dependent constant, take a look at the code
* @param J Wordsize-dependent constant, take a look at the code
* @param K Wordsize-dependent constant, take a look at the code
* @param L Wordsize-dependent constant, take a look at the code
* @param WORD_T `__typeof()` on any wordsize-dependent variable, with exact size
* @param k Round constants
* @param w Words
* @param h Hash values
* @param work_h Space for temporary hash values
*/
#define SHA2_IMPLEMENTATION(A, B, C, D, E, F, G, H, I, J, K, L, WORD_T, k, w, h, work_h) \
memcpy(work_h, h, sizeof(work_h)); \
\
memset(w, 0, 16 * sizeof(*(w))); \
for (i = 0; i < 16; i++) \
for (j = 0; j < sizeof(WORD_T); j++) \
w[i] |= ((WORD_T)(state->chunk[(i + 1) * sizeof(WORD_T) - j - 1])) << (j << 3); \
\
for (i = 16; i < sizeof(k) / sizeof(*(k)); i++) \
{ \
w[i] = w[i - 16] + w[i - 7]; \
w[i] += ROTR(w[i - 15], A) ^ ROTR(w[i - 15], B) ^ (w[i - 15] >> (C)); \
w[i] += ROTR(w[i - 2], D) ^ ROTR(w[i - 2], E) ^ (w[i - 2] >> (F)); \
} \
\
for (i = 0; i < sizeof(k) / sizeof(*(k)); i++) \
{ \
s1 = (work_h[4] & work_h[5]) ^ (work_h[6] & ~(work_h[4])); \
s1 += work_h[7] + k[i] + w[i]; \
s0 = (work_h[0] & work_h[1]) ^ (work_h[0] & work_h[2]) ^ (work_h[1] & work_h[2]); \
s1 += ROTR(work_h[4], G) ^ ROTR(work_h[4], H) ^ ROTR(work_h[4], I); \
s0 += ROTR(work_h[0], J) ^ ROTR(work_h[0], K) ^ ROTR(work_h[0], L); \
\
memmove(work_h + 1, work_h, 7 * sizeof(*(work_h))); \
work_h[4] += s1; \
work_h[0] = s1 + s0; \
} \
\
for (i = 0; i < 8; i++) \
h[i] += work_h[i]
/**
* Process a chunk using SHA-256
*
* @param state The hashing state
*/
__attribute__((nonnull, nothrow))
static void process256(libsha2_state_t* restrict state)
{
uint32_t s0, s1;
size_t i, j;
#define ROTR(X, N) (((X) >> (N)) | ((X) << ((sizeof(uint32_t) * 8) - (N))))
SHA2_IMPLEMENTATION(7, 18, 3, 17, 19, 10, 6, 11, 25, 2, 13, 22, uint32_t,
state->k.b32, state->w.b32, state->h.b32, state->work_h.b32);
#undef ROTR
}
/**
* Process a chunk using SHA-512
*
* @param state The hashing state
*/
__attribute__((nonnull, nothrow))
static void process512(libsha2_state_t* restrict state)
{
uint64_t s0, s1;
size_t i, j;
#define ROTR(X, N) (((X) >> (N)) | ((X) << ((sizeof(uint64_t) * 8) - (N))))
SHA2_IMPLEMENTATION(1, 8, 7, 19, 61, 6, 14, 18, 41, 28, 34, 39, uint64_t,
state->k.b64, state->w.b64, state->h.b64, state->work_h.b64);
#undef ROTR
}
/**
* Absorb more of the message
*
* @param state The hashing state
* @param message The message, in bits, must be equivalent to 0 modulus 8
* @param msglen The length of the message
*/
void libsha2_update(libsha2_state_t* restrict state, const char* restrict message, size_t msglen)
{
size_t n, off, mlen;
msglen /= 8;
mlen = state->message_size / 8;
while (msglen)
{
off = mlen % state->chunk_size;
n = state->chunk_size - off;
n = n < msglen ? n : msglen;
memcpy(state->chunk + off, message, n);
if (off + n == state->chunk_size)
switch (state->algorithm)
{
case LIBSHA2_224:
case LIBSHA2_256:
process256(state);
break;
default:
process512(state);
break;
}
message += n, mlen += n, msglen -= n;
}
state->message_size = mlen * 8;
}
/**
* Absorb the last part of the message and output a hash
*
* @param state The hashing state
* @param message The message, in bits
* @param msglen The length of the message, zero if there is nothing more to absorb
* @param output The output buffer for the hash
*/
void libsha2_digest(libsha2_state_t* restrict state, const char* restrict message, size_t msglen, char* output)
{
char* appendix;
size_t i, j, k, n;
if (msglen & ~7)
{
libsha2_update(state, message, msglen & ~7);
message += msglen & ~7;
msglen &= 7;
}
k = 8 * state->chunk_size;
n = state->chunk_size + 8;
n = (k + (n % k)) % k;
n = n / 8 - 1;
appendix = state->appendix;
if (msglen)
{
j = 7 - msglen;
*appendix = *message;
*appendix |= 1 << j;
*appendix &= ~((1 << j) - 1);
}
else
*appendix = (unsigned char)128;
k = state->message_size + msglen;
i = state->chunk_size / 8;
appendix += n + i - 1;
for (i = i < sizeof(size_t) ? i : sizeof(size_t); i--;)
*(appendix - i) = (unsigned char)((k >> (i * 8)) & 255);
n += state->chunk_size;
libsha2_update(state, state->appendix, n);
n = libsha2_algorithm_output_size(state->algorithm);
switch (state->algorithm)
{
case LIBSHA2_224:
case LIBSHA2_256:
for (i = 0; i < 8; i++)
for (j = 0; j < (state->chunk_size / 16); j++)
if (k = (i + 1) * (state->chunk_size / 16) - j - 1, k < n)
output[k] = (char)((state->h.b32[i] >> (8 * j)) & 255);
break;
default:
for (i = 0; i < 8; i++)
for (j = 0; j < (state->chunk_size / 16); j++)
if (k = (i + 1) * (state->chunk_size / 16) - j - 1, k < n)
output[k] = (char)((state->h.b64[i] >> (8 * j)) & 255);
break;
}
}
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