80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
|
// Copyright (c) 2016, Google Inc.
|
||
|
|
// SPDX-License-Identifier: ISC
|
||
|
|
|
||
|
|
#include <openssl/base.h>
|
||
|
|
|
||
|
|
#include <assert.h>
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
#include "internal.h"
|
||
|
|
#include "../../internal.h"
|
||
|
|
|
||
|
|
|
||
|
|
// byte_reverse reverses the order of the bytes in |b->c|.
|
||
|
|
static void byte_reverse(uint8_t b[16]) {
|
||
|
|
uint64_t hi = CRYPTO_load_u64_le(b);
|
||
|
|
uint64_t lo = CRYPTO_load_u64_le(b + 8);
|
||
|
|
CRYPTO_store_u64_le(b, CRYPTO_bswap8(lo));
|
||
|
|
CRYPTO_store_u64_le(b + 8, CRYPTO_bswap8(hi));
|
||
|
|
}
|
||
|
|
|
||
|
|
// reverse_and_mulX_ghash interprets |b| as a reversed element of the GHASH
|
||
|
|
// field, multiplies that by 'x' and serialises the result back into |b|, but
|
||
|
|
// with GHASH's backwards bit ordering.
|
||
|
|
static void reverse_and_mulX_ghash(uint8_t b[16]) {
|
||
|
|
uint64_t hi = CRYPTO_load_u64_le(b);
|
||
|
|
uint64_t lo = CRYPTO_load_u64_le(b + 8);
|
||
|
|
const crypto_word_t carry = constant_time_eq_w(hi & 1, 1);
|
||
|
|
hi >>= 1;
|
||
|
|
hi |= lo << 63;
|
||
|
|
lo >>= 1;
|
||
|
|
lo ^= ((uint64_t) constant_time_select_w(carry, 0xe1, 0)) << 56;
|
||
|
|
|
||
|
|
CRYPTO_store_u64_le(b, CRYPTO_bswap8(lo));
|
||
|
|
CRYPTO_store_u64_le(b + 8, CRYPTO_bswap8(hi));
|
||
|
|
}
|
||
|
|
|
||
|
|
// POLYVAL(H, X_1, ..., X_n) =
|
||
|
|
// ByteReverse(GHASH(mulX_GHASH(ByteReverse(H)), ByteReverse(X_1), ...,
|
||
|
|
// ByteReverse(X_n))).
|
||
|
|
//
|
||
|
|
// See https://www.rfc-editor.org/rfc/rfc8452.html#appendix-A.
|
||
|
|
|
||
|
|
void CRYPTO_POLYVAL_init(struct polyval_ctx *ctx, const uint8_t key[16]) {
|
||
|
|
alignas(8) uint8_t H[16];
|
||
|
|
OPENSSL_memcpy(H, key, 16);
|
||
|
|
reverse_and_mulX_ghash(H);
|
||
|
|
|
||
|
|
int is_avx;
|
||
|
|
CRYPTO_ghash_init(&ctx->gmult, &ctx->ghash, ctx->Htable, &is_avx, H);
|
||
|
|
OPENSSL_memset(&ctx->S, 0, sizeof(ctx->S));
|
||
|
|
}
|
||
|
|
|
||
|
|
void CRYPTO_POLYVAL_update_blocks(struct polyval_ctx *ctx, const uint8_t *in,
|
||
|
|
size_t in_len) {
|
||
|
|
assert((in_len & 15) == 0);
|
||
|
|
alignas(8) uint8_t buf[32 * 16];
|
||
|
|
|
||
|
|
while (in_len > 0) {
|
||
|
|
size_t todo = in_len;
|
||
|
|
if (todo > sizeof(buf)) {
|
||
|
|
todo = sizeof(buf);
|
||
|
|
}
|
||
|
|
OPENSSL_memcpy(buf, in, todo);
|
||
|
|
in += todo;
|
||
|
|
in_len -= todo;
|
||
|
|
|
||
|
|
size_t blocks = todo / 16;
|
||
|
|
for (size_t i = 0; i < blocks; i++) {
|
||
|
|
byte_reverse(buf + 16 * i);
|
||
|
|
}
|
||
|
|
|
||
|
|
ctx->ghash(ctx->S, ctx->Htable, buf, todo);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void CRYPTO_POLYVAL_finish(const struct polyval_ctx *ctx, uint8_t out[16]) {
|
||
|
|
OPENSSL_memcpy(out, &ctx->S, 16);
|
||
|
|
byte_reverse(out);
|
||
|
|
}
|