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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 "tls/extensions/s2n_cert_status.h"
#include "tls/s2n_config.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_tls.h"
#include "tls/s2n_x509_validator.h"
#include "utils/s2n_safety.h"
#define U24_SIZE 3
static bool s2n_cert_status_should_send(struct s2n_connection *conn);
/*
* The cert_status extension is sent in response to OCSP status requests in TLS 1.3. The
* OCSP response is contained in the extension data. In TLS 1.2, the cert_status_response
* extension is sent instead, indicating that the OCSP response will be sent in a
* Certificate Status handshake message.
*/
const s2n_extension_type s2n_cert_status_extension = {
.iana_value = TLS_EXTENSION_STATUS_REQUEST,
.is_response = true,
.send = s2n_cert_status_send,
.recv = s2n_cert_status_recv,
.should_send = s2n_cert_status_should_send,
.if_missing = s2n_extension_noop_if_missing,
};
static bool s2n_cert_status_should_send(struct s2n_connection *conn)
{
return conn->handshake_params.our_chain_and_key
&& conn->handshake_params.our_chain_and_key->ocsp_status.size > 0;
}
int s2n_cert_status_send(struct s2n_connection *conn, struct s2n_stuffer *out)
{
POSIX_ENSURE_REF(conn);
struct s2n_blob *ocsp_status = &conn->handshake_params.our_chain_and_key->ocsp_status;
POSIX_ENSURE_REF(ocsp_status);
POSIX_GUARD(s2n_stuffer_write_uint8(out, (uint8_t) S2N_STATUS_REQUEST_OCSP));
POSIX_GUARD(s2n_stuffer_write_uint24(out, ocsp_status->size));
POSIX_GUARD(s2n_stuffer_write(out, ocsp_status));
return S2N_SUCCESS;
}
int s2n_cert_status_recv(struct s2n_connection *conn, struct s2n_stuffer *in)
{
POSIX_ENSURE_REF(conn);
/**
*= https://tools.ietf.org/rfc/rfc6066#section-8
*# struct {
*# CertificateStatusType status_type;
*# select (status_type) {
*# case ocsp: OCSPResponse;
*# } response;
*# } CertificateStatus;
*#
*# opaque OCSPResponse<1..2^24-1>;
*#
*# An "ocsp_response" contains a complete, DER-encoded OCSP response
*# (using the ASN.1 type OCSPResponse defined in [RFC2560]). Only one
*# OCSP response may be sent.
**/
uint8_t type;
POSIX_GUARD(s2n_stuffer_read_uint8(in, &type));
if (type != S2N_STATUS_REQUEST_OCSP) {
/* We only support OCSP */
return S2N_SUCCESS;
}
/* The status_type variable is only used when a client requests OCSP stapling from a
* server. A server can request OCSP stapling from a client, but it is not tracked
* with this variable.
*/
if (conn->mode == S2N_CLIENT) {
conn->status_type = S2N_STATUS_REQUEST_OCSP;
}
uint32_t status_size;
POSIX_GUARD(s2n_stuffer_read_uint24(in, &status_size));
POSIX_ENSURE_LTE(status_size, s2n_stuffer_data_available(in));
POSIX_GUARD(s2n_realloc(&conn->status_response, status_size));
POSIX_GUARD(s2n_stuffer_read_bytes(in, conn->status_response.data, status_size));
POSIX_GUARD_RESULT(s2n_x509_validator_validate_cert_stapled_ocsp_response(&conn->x509_validator, conn,
conn->status_response.data, conn->status_response.size));
return S2N_SUCCESS;
}
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