s2n_encrypted_extensions.c

/*
 * 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 "error/s2n_errno.h"
#include "stuffer/s2n_stuffer.h"
#include "tls/extensions/s2n_extension_list.h"
#include "tls/s2n_tls.h"
#include "tls/s2n_tls13.h"
#include "utils/s2n_safety.h"

/**
  * Specified in https://tools.ietf.org/html/rfc8446#section-4.3.1
  *
  * In all handshakes, the server MUST send the EncryptedExtensions
  * message immediately after the ServerHello message.
  *
  * The EncryptedExtensions message contains extensions that can be
  * protected, i.e., any which are not needed to establish the
  * cryptographic context but which are not associated with individual
  * certificates.
  **/

int s2n_encrypted_extensions_send(struct s2n_connection *conn)
{
    POSIX_ENSURE_REF(conn);
    POSIX_ENSURE(conn->actual_protocol_version >= S2N_TLS13, S2N_ERR_BAD_MESSAGE);

    struct s2n_stuffer *out = &conn->handshake.io;
    POSIX_GUARD(s2n_extension_list_send(S2N_EXTENSION_LIST_ENCRYPTED_EXTENSIONS, conn, out));
    return S2N_SUCCESS;
}

int s2n_encrypted_extensions_recv(struct s2n_connection *conn)
{
    POSIX_ENSURE_REF(conn);
    POSIX_ENSURE(conn->actual_protocol_version >= S2N_TLS13, S2N_ERR_BAD_MESSAGE);

    struct s2n_stuffer *in = &conn->handshake.io;
    POSIX_GUARD(s2n_extension_list_recv(S2N_EXTENSION_LIST_ENCRYPTED_EXTENSIONS, conn, in));
    return S2N_SUCCESS;
}