Lockpick/source/sha256.c

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2018-12-08 02:17:01 +01:00
/* Based on linux source code */
/*
* sha256_base.h - core logic for SHA-256 implementations
*
* Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifdef __cplusplus
extern "C" {
#endif
#include <string.h>
#include "sha256.h"
#define unlikely(x) __builtin_expect(!!(x), 0)
void sha256_block_data_order (uint32_t *ctx, const void *in, size_t num);
int sha256_init(struct sha256_state *sctx)
{
sctx->state[0] = SHA256_H0;
sctx->state[1] = SHA256_H1;
sctx->state[2] = SHA256_H2;
sctx->state[3] = SHA256_H3;
sctx->state[4] = SHA256_H4;
sctx->state[5] = SHA256_H5;
sctx->state[6] = SHA256_H6;
sctx->state[7] = SHA256_H7;
sctx->count = 0;
return 0;
}
int sha256_update(struct sha256_state *sctx,
const void *data,
size_t len)
{
const u8 *data8 = (const u8 *)data;
unsigned int len32 = (unsigned int)len;
unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
sctx->count += len32;
if (unlikely((partial + len32) >= SHA256_BLOCK_SIZE)) {
int blocks;
if (partial) {
int p = SHA256_BLOCK_SIZE - partial;
memcpy(sctx->buf + partial, data8, p);
data8 += p;
len32 -= p;
sha256_block_data_order(sctx->state, sctx->buf, 1);
}
blocks = len32 / SHA256_BLOCK_SIZE;
len32 %= SHA256_BLOCK_SIZE;
if (blocks) {
sha256_block_data_order(sctx->state, data8, blocks);
data8 += blocks * SHA256_BLOCK_SIZE;
}
partial = 0;
}
if (len32)
memcpy(sctx->buf + partial, data8, len32);
return 0;
}
int sha256_finalize(struct sha256_state *sctx)
{
const int bit_offset = SHA256_BLOCK_SIZE - sizeof(u64);
u64 *bits = (u64 *)(sctx->buf + bit_offset);
unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
sctx->buf[partial++] = 0x80;
if (partial > bit_offset) {
memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
partial = 0;
sha256_block_data_order(sctx->state, sctx->buf, 1);
}
memset(sctx->buf + partial, 0x0, bit_offset - partial);
*bits = __builtin_bswap64(sctx->count << 3);
sha256_block_data_order(sctx->state, sctx->buf, 1);
return 0;
}
int sha256_finish(struct sha256_state *sctx, void *out)
{
unsigned int digest_size = 32;
u32 *digest = (u32 *)out;
int i;
// Switch: misalignment shouldn't be a problem here...
for (i = 0; digest_size > 0; i++, digest_size -= sizeof(u32))
*digest++ = __builtin_bswap32(sctx->state[i]);
*sctx = (struct sha256_state){};
return 0;
}
#ifdef __cplusplus
}
#endif