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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 <sys/param.h>
#include "tls/extensions/s2n_client_pq_kem.h"
#include "tls/s2n_kem.h"
#include "tls/s2n_security_policies.h"
#include "tls/s2n_tls.h"
#include "tls/s2n_tls_parameters.h"
#include "pq-crypto/s2n_pq.h"
#include "utils/s2n_safety.h"
static bool s2n_client_pq_kem_should_send(struct s2n_connection *conn);
static int s2n_client_pq_kem_send(struct s2n_connection *conn, struct s2n_stuffer *out);
static int s2n_client_pq_kem_recv(struct s2n_connection *conn, struct s2n_stuffer *extension);
const s2n_extension_type s2n_client_pq_kem_extension = {
.iana_value = TLS_EXTENSION_PQ_KEM_PARAMETERS,
.is_response = false,
.send = s2n_client_pq_kem_send,
.recv = s2n_client_pq_kem_recv,
.should_send = s2n_client_pq_kem_should_send,
.if_missing = s2n_extension_noop_if_missing,
};
static bool s2n_client_pq_kem_should_send(struct s2n_connection *conn)
{
const struct s2n_security_policy *security_policy;
return s2n_connection_get_security_policy(conn, &security_policy) == S2N_SUCCESS
&& s2n_pq_kem_is_extension_required(security_policy)
&& s2n_pq_is_enabled();
}
static int s2n_client_pq_kem_send(struct s2n_connection *conn, struct s2n_stuffer *out)
{
const struct s2n_kem_preferences *kem_preferences = NULL;
POSIX_GUARD(s2n_connection_get_kem_preferences(conn, &kem_preferences));
POSIX_ENSURE_REF(kem_preferences);
POSIX_GUARD(s2n_stuffer_write_uint16(out, kem_preferences->kem_count * sizeof(kem_extension_size)));
for (int i = 0; i < kem_preferences->kem_count; i++) {
POSIX_GUARD(s2n_stuffer_write_uint16(out, kem_preferences->kems[i]->kem_extension_id));
}
return S2N_SUCCESS;
}
static int s2n_client_pq_kem_recv(struct s2n_connection *conn, struct s2n_stuffer *extension)
{
uint16_t size_of_all;
struct s2n_blob *proposed_kems = &conn->kex_params.client_pq_kem_extension;
/* Ignore extension if PQ is disabled */
if (!s2n_pq_is_enabled()) {
return S2N_SUCCESS;
}
POSIX_GUARD(s2n_stuffer_read_uint16(extension, &size_of_all));
if (size_of_all > s2n_stuffer_data_available(extension) || size_of_all % sizeof(kem_extension_size)) {
/* Malformed length, ignore the extension */
return S2N_SUCCESS;
}
proposed_kems->size = size_of_all;
proposed_kems->data = s2n_stuffer_raw_read(extension, proposed_kems->size);
POSIX_ENSURE_REF(proposed_kems->data);
return S2N_SUCCESS;
}
/* Old-style extension functions -- remove after extensions refactor is complete */
int s2n_extensions_client_pq_kem_send(struct s2n_connection *conn, struct s2n_stuffer *out, uint16_t pq_kem_list_size)
{
return s2n_extension_send(&s2n_client_pq_kem_extension, conn, out);
}
int s2n_recv_pq_kem_extension(struct s2n_connection *conn, struct s2n_stuffer *extension)
{
return s2n_extension_recv(&s2n_client_pq_kem_extension, conn, extension);
}
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