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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include <stdint.h>
#include "error/s2n_errno.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_tls.h"
#include "tls/s2n_tls13_handshake.h"
#include "stuffer/s2n_stuffer.h"
#include "utils/s2n_safety.h"
int s2n_client_finished_recv(struct s2n_connection *conn)
{
uint8_t *our_version;
our_version = conn->handshake.client_finished;
uint8_t *their_version = s2n_stuffer_raw_read(&conn->handshake.io, S2N_TLS_FINISHED_LEN);
notnull_check(their_version);
S2N_ERROR_IF(!s2n_constant_time_equals(our_version, their_version, S2N_TLS_FINISHED_LEN) || conn->handshake.rsa_failed, S2N_ERR_BAD_MESSAGE);
return 0;
}
int s2n_client_finished_send(struct s2n_connection *conn)
{
uint8_t *our_version;
GUARD(s2n_prf_client_finished(conn));
struct s2n_blob seq = {.data = conn->secure.client_sequence_number,.size = sizeof(conn->secure.client_sequence_number) };
GUARD(s2n_blob_zero(&seq));
our_version = conn->handshake.client_finished;
/* Update the server to use the cipher suite */
conn->client = &conn->secure;
if (conn->actual_protocol_version == S2N_SSLv3) {
GUARD(s2n_stuffer_write_bytes(&conn->handshake.io, our_version, S2N_SSL_FINISHED_LEN));
} else {
GUARD(s2n_stuffer_write_bytes(&conn->handshake.io, our_version, S2N_TLS_FINISHED_LEN));
}
return 0;
}
int s2n_tls13_client_finished_recv(struct s2n_connection *conn) {
eq_check(conn->actual_protocol_version, S2N_TLS13);
uint8_t length = s2n_stuffer_data_available(&conn->handshake.io);
S2N_ERROR_IF(length == 0, S2N_ERR_BAD_MESSAGE);
/* read finished mac from handshake */
struct s2n_blob wire_finished_mac = {0};
s2n_blob_init(&wire_finished_mac, s2n_stuffer_raw_read(&conn->handshake.io, length), length);
/* get tls13 keys */
s2n_tls13_connection_keys(keys, conn);
/* get transcript hash */
struct s2n_hash_state hash_state = {0};
GUARD(s2n_handshake_get_hash_state(conn, keys.hash_algorithm, &hash_state));
struct s2n_blob finished_key = {0};
GUARD(s2n_blob_init(&finished_key, conn->handshake.client_finished, keys.size));
s2n_tls13_key_blob(client_finished_mac, keys.size);
GUARD(s2n_tls13_calculate_finished_mac(&keys, &finished_key, &hash_state, &client_finished_mac));
GUARD(s2n_tls13_mac_verify(&keys, &client_finished_mac, &wire_finished_mac));
return 0;
}
int s2n_tls13_client_finished_send(struct s2n_connection *conn) {
eq_check(conn->actual_protocol_version, S2N_TLS13);
/* get tls13 keys */
s2n_tls13_connection_keys(keys, conn);
/* get transcript hash */
struct s2n_hash_state hash_state = {0};
GUARD(s2n_handshake_get_hash_state(conn, keys.hash_algorithm, &hash_state));
/* look up finished secret key */
struct s2n_blob finished_key = {0};
GUARD(s2n_blob_init(&finished_key, conn->handshake.client_finished, keys.size));
/* generate the hashed message authenticated code */
s2n_stack_blob(client_finished_mac, keys.size, S2N_TLS13_SECRET_MAX_LEN);
GUARD(s2n_tls13_calculate_finished_mac(&keys, &finished_key, &hash_state, &client_finished_mac));
/* write to handshake io */
GUARD(s2n_stuffer_write(&conn->handshake.io, &client_finished_mac));
return 0;
}
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