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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.
*/
/* Target Functions: s2n_client_key_recv s2n_kex_client_key_recv calculate_keys
s2n_hybrid_client_action s2n_kex_tls_prf s2n_prf_key_expansion
s2n_rsa_client_key_recv s2n_dhe_client_key_recv
s2n_ecdhe_client_key_recv s2n_kem_client_key_recv */
#include <stdint.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include "tls/s2n_kem.h"
#include "tls/s2n_client_key_exchange.h"
#include "tls/s2n_kex.h"
#include "tls/s2n_security_policies.h"
#include "api/s2n.h"
#include "stuffer/s2n_stuffer.h"
#include "tls/s2n_cipher_preferences.h"
#include "tls/s2n_cipher_suites.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_tls.h"
#include "utils/s2n_safety.h"
#include "s2n_test.h"
#include "testlib/s2n_testlib.h"
static const uint8_t TLS_VERSIONS[] = {S2N_TLS10, S2N_TLS11, S2N_TLS12};
/* Connection setup variables */
uint8_t *cert_chain_pem = NULL;
uint8_t *private_key_pem = NULL;
char *dhparams_pem = NULL;
uint32_t cert_chain_len = 0;
uint32_t private_key_len = 0;
struct s2n_config *config;
struct s2n_cert_chain_and_key *chain_and_key;
struct s2n_cert_chain_and_key *cert;
struct s2n_cipher_suite **test_suites;
int num_suites;
int s2n_fuzz_init(int *argc, char **argv[])
{
#ifdef S2N_TEST_IN_FIPS_MODE
test_suites = cipher_preferences_test_all_fips.suites;
num_suites = cipher_preferences_test_all_fips.count;
#else
test_suites = cipher_preferences_test_all.suites;
num_suites = cipher_preferences_test_all.count;
#endif
/* One time Diffie-Hellman negotiation to speed along fuzz tests*/
cert_chain_pem = malloc(S2N_MAX_TEST_PEM_SIZE);
private_key_pem = malloc(S2N_MAX_TEST_PEM_SIZE);
dhparams_pem = malloc(S2N_MAX_TEST_PEM_SIZE);
POSIX_ENSURE_REF(cert_chain_pem);
POSIX_ENSURE_REF(private_key_pem);
POSIX_ENSURE_REF(dhparams_pem);
s2n_read_test_pem_and_len(S2N_DEFAULT_TEST_CERT_CHAIN, cert_chain_pem, &cert_chain_len, S2N_MAX_TEST_PEM_SIZE);
s2n_read_test_pem_and_len(S2N_DEFAULT_TEST_PRIVATE_KEY, private_key_pem, &private_key_len, S2N_MAX_TEST_PEM_SIZE);
s2n_read_test_pem(S2N_DEFAULT_TEST_DHPARAMS, dhparams_pem, S2N_MAX_TEST_PEM_SIZE);
config = s2n_config_new();
chain_and_key = s2n_cert_chain_and_key_new();
POSIX_ENSURE_REF(config);
POSIX_ENSURE_REF(chain_and_key);
s2n_cert_chain_and_key_load_pem_bytes(chain_and_key, cert_chain_pem, cert_chain_len, private_key_pem, private_key_len);
s2n_config_add_cert_chain_and_key_to_store(config, chain_and_key);
s2n_config_add_dhparams(config, dhparams_pem);
cert = s2n_config_get_single_default_cert(config);
POSIX_ENSURE_REF(cert);
return S2N_SUCCESS;
}
int s2n_fuzz_test(const uint8_t *buf, size_t len)
{
/* We need at least two bytes of input to set parameters */
S2N_FUZZ_ENSURE_MIN_LEN(len, 2);
/* Setup */
struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
POSIX_ENSURE_REF(server_conn);
POSIX_GUARD(s2n_stuffer_write_bytes(&server_conn->handshake.io, buf, len));
/* Read bytes from the libfuzzer input and use them to set parameters */
uint8_t randval = 0;
POSIX_GUARD(s2n_stuffer_read_uint8(&server_conn->handshake.io, &randval));
server_conn->server_protocol_version = TLS_VERSIONS[randval % s2n_array_len(TLS_VERSIONS)];
POSIX_GUARD(s2n_stuffer_read_uint8(&server_conn->handshake.io, &randval));
server_conn->secure->cipher_suite = test_suites[randval % num_suites];
/* Skip incompatible TLS 1.3 cipher suites */
if (server_conn->secure->cipher_suite->key_exchange_alg == NULL) {
POSIX_GUARD(s2n_connection_free(server_conn));
return S2N_SUCCESS;
}
server_conn->handshake_params.our_chain_and_key = cert;
const struct s2n_ecc_preferences *ecc_preferences = NULL;
POSIX_GUARD(s2n_connection_get_ecc_preferences(server_conn, &ecc_preferences));
POSIX_ENSURE_REF(ecc_preferences);
if (server_conn->secure->cipher_suite->key_exchange_alg->client_key_recv == s2n_ecdhe_client_key_recv || server_conn->secure->cipher_suite->key_exchange_alg->client_key_recv == s2n_hybrid_client_key_recv) {
server_conn->kex_params.server_ecc_evp_params.negotiated_curve = ecc_preferences->ecc_curves[0];
s2n_ecc_evp_generate_ephemeral_key(&server_conn->kex_params.server_ecc_evp_params);
}
if (server_conn->secure->cipher_suite->key_exchange_alg->client_key_recv == s2n_kem_client_key_recv || server_conn->secure->cipher_suite->key_exchange_alg->client_key_recv == s2n_hybrid_client_key_recv) {
server_conn->kex_params.kem_params.kem = &s2n_kyber_512_r3;
}
/* Run Test
* Do not use GUARD macro here since the connection memory hasn't been freed.
*/
s2n_client_key_recv(server_conn);
/* Cleanup */
POSIX_GUARD(s2n_connection_free(server_conn));
return S2N_SUCCESS;
}
static void s2n_fuzz_cleanup()
{
free(cert_chain_pem);
free(private_key_pem);
free(dhparams_pem);
s2n_config_free(config);
s2n_cert_chain_and_key_free(chain_and_key);
}
S2N_FUZZ_TARGET(s2n_fuzz_init, s2n_fuzz_test, s2n_fuzz_cleanup)
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