/* reverse_and_mulX_ghash interprets the bytes |b->c| 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(polyval_block *b) {
uint64_t hi = b->u[0];
uint64_t lo = b->u[1];
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;
b->u[0] = CRYPTO_bswap8(lo);
b->u[1] = CRYPTO_bswap8(hi);
}
static int aead_aes_gcm_tls12_seal_scatter(
const EVP_AEAD_CTX *ctx, uint8_t *out, uint8_t *out_tag,
size_t *out_tag_len, size_t max_out_tag_len, const uint8_t *nonce,
size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *extra_in,
size_t extra_in_len, const uint8_t *ad, size_t ad_len) {
struct aead_aes_gcm_tls12_ctx *gcm_ctx = ctx->aead_state;
if (nonce_len != 12) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE);
return 0;
}
// The given nonces must be strictly monotonically increasing.
uint64_t given_counter;
OPENSSL_memcpy(&given_counter, nonce + nonce_len - sizeof(given_counter),
sizeof(given_counter));
given_counter = CRYPTO_bswap8(given_counter);
if (given_counter == UINT64_MAX ||
given_counter < gcm_ctx->min_next_nonce) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_NONCE);
return 0;
}
gcm_ctx->min_next_nonce = given_counter + 1;
return aead_aes_gcm_seal_scatter(ctx, out, out_tag, out_tag_len,
max_out_tag_len, nonce, nonce_len, in,
in_len, extra_in, extra_in_len, ad, ad_len);
}
int ASN1_INTEGER_set_uint64(ASN1_INTEGER *out, uint64_t v)
{
uint8_t *const newdata = OPENSSL_malloc(sizeof(uint64_t));
if (newdata == NULL) {
OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
return 0;
}
OPENSSL_free(out->data);
out->data = newdata;
v = CRYPTO_bswap8(v);
memcpy(out->data, &v, sizeof(v));
out->type = V_ASN1_INTEGER;
size_t leading_zeros;
for (leading_zeros = 0; leading_zeros < sizeof(uint64_t) - 1;
leading_zeros++) {
if (out->data[leading_zeros] != 0) {
break;
}
}
out->length = sizeof(uint64_t) - leading_zeros;
OPENSSL_memmove(out->data, out->data + leading_zeros, out->length);
return 1;
}
static int aead_aes_gcm_tls13_seal_scatter(
const EVP_AEAD_CTX *ctx, uint8_t *out, uint8_t *out_tag,
size_t *out_tag_len, size_t max_out_tag_len, const uint8_t *nonce,
size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *extra_in,
size_t extra_in_len, const uint8_t *ad, size_t ad_len) {
struct aead_aes_gcm_tls13_ctx *gcm_ctx =
(struct aead_aes_gcm_tls13_ctx *) &ctx->state;
if (nonce_len != 12) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE);
return 0;
}
// The given nonces must be strictly monotonically increasing. See
// https://tools.ietf.org/html/rfc8446#section-5.3 for details of the TLS 1.3
// nonce construction.
uint64_t given_counter;
OPENSSL_memcpy(&given_counter, nonce + nonce_len - sizeof(given_counter),
sizeof(given_counter));
given_counter = CRYPTO_bswap8(given_counter);
if (gcm_ctx->first) {
// In the first call the sequence number will be zero and therefore the
// given nonce will be 0 ^ mask = mask.
gcm_ctx->mask = given_counter;
gcm_ctx->first = 0;
}
given_counter ^= gcm_ctx->mask;
if (given_counter == UINT64_MAX ||
given_counter < gcm_ctx->min_next_nonce) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_NONCE);
return 0;
}
gcm_ctx->min_next_nonce = given_counter + 1;
return aead_aes_gcm_seal_scatter(ctx, out, out_tag, out_tag_len,
max_out_tag_len, nonce, nonce_len, in,
in_len, extra_in, extra_in_len, ad, ad_len);
}
/* byte_reverse reverses the order of the bytes in |b->c|. */
static void byte_reverse(polyval_block *b) {
const uint64_t t = CRYPTO_bswap8(b->u[0]);
b->u[0] = CRYPTO_bswap8(b->u[1]);
b->u[1] = t;
}
