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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 <s2n.h>
#include "error/s2n_errno.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_config.h"
#include "tls/s2n_signature_algorithms.h"
#include "tls/s2n_tls.h"
#include "stuffer/s2n_stuffer.h"
#include "utils/s2n_safety.h"
int s2n_client_cert_verify_recv(struct s2n_connection *conn)
{
struct s2n_stuffer *in = &conn->handshake.io;
struct s2n_signature_scheme chosen_sig_scheme = s2n_rsa_pkcs1_md5_sha1;
if(conn->actual_protocol_version >= S2N_TLS12){
/* Verify the SigScheme picked by the Client was in the preference list we sent (or is the default SigScheme) */
GUARD(s2n_get_and_validate_negotiated_signature_scheme(conn, in, &chosen_sig_scheme));
}
uint16_t signature_size;
struct s2n_blob signature = {0};
GUARD(s2n_stuffer_read_uint16(in, &signature_size));
signature.size = signature_size;
signature.data = s2n_stuffer_raw_read(in, signature.size);
notnull_check(signature.data);
/* Use a copy of the hash state since the verify digest computation may modify the running hash state we need later. */
struct s2n_hash_state hash_state = {0};
GUARD(s2n_handshake_get_hash_state(conn, chosen_sig_scheme.hash_alg, &hash_state));
GUARD(s2n_hash_copy(&conn->handshake.ccv_hash_copy, &hash_state));
/* Verify the signature */
GUARD(s2n_pkey_verify(&conn->secure.client_public_key, chosen_sig_scheme.sig_alg, &conn->handshake.ccv_hash_copy, &signature));
/* Client certificate has been verified. Minimize required handshake hash algs */
GUARD(s2n_conn_update_required_handshake_hashes(conn));
return 0;
}
int s2n_client_cert_verify_send(struct s2n_connection *conn)
{
struct s2n_stuffer *out = &conn->handshake.io;
struct s2n_signature_scheme chosen_sig_scheme = s2n_rsa_pkcs1_md5_sha1;
if (conn->actual_protocol_version >= S2N_TLS12) {
chosen_sig_scheme = conn->secure.client_cert_sig_scheme;
GUARD(s2n_stuffer_write_uint16(out, conn->secure.client_cert_sig_scheme.iana_value));
}
/* Use a copy of the hash state since the verify digest computation may modify the running hash state we need later. */
struct s2n_hash_state hash_state = {0};
GUARD(s2n_handshake_get_hash_state(conn, chosen_sig_scheme.hash_alg, &hash_state));
GUARD(s2n_hash_copy(&conn->handshake.ccv_hash_copy, &hash_state));
struct s2n_cert_chain_and_key *cert_chain_and_key = conn->handshake_params.our_chain_and_key;
DEFER_CLEANUP(struct s2n_blob signature = {0}, s2n_free);
uint32_t max_signature_size = s2n_pkey_size(cert_chain_and_key->private_key);
GUARD(s2n_alloc(&signature, max_signature_size));
GUARD(s2n_pkey_sign(cert_chain_and_key->private_key, chosen_sig_scheme.sig_alg, &conn->handshake.ccv_hash_copy, &signature));
GUARD(s2n_stuffer_write_uint16(out, signature.size));
GUARD(s2n_stuffer_write(out, &signature));
/* Client certificate has been verified. Minimize required handshake hash algs */
GUARD(s2n_conn_update_required_handshake_hashes(conn));
return 0;
}
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