/*
 * 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_tls13_cert_verify_recv s2n_get_and_validate_negotiated_signature_scheme
                     s2n_tls13_cert_read_and_verify_signature */

#include <stdint.h>

#include <openssl/crypto.h>
#include <openssl/err.h>

#include "api/s2n.h"
#include "stuffer/s2n_stuffer.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"

uint8_t *cert_chain = NULL;
uint8_t *private_key = NULL;
uint32_t cert_chain_len = 0;
uint32_t private_key_len = 0;
struct s2n_cert_chain_and_key *default_cert;
struct s2n_config *conn_config;

int s2n_fuzz_init(int *argc, char **argv[])
{
    /* Initialize test chain and key */
    cert_chain = malloc(S2N_MAX_TEST_PEM_SIZE);
    POSIX_ENSURE_REF(cert_chain);
    private_key = malloc(S2N_MAX_TEST_PEM_SIZE);
    POSIX_ENSURE_REF(private_key);
    default_cert = s2n_cert_chain_and_key_new();
    POSIX_ENSURE_REF(default_cert);
    conn_config = s2n_config_new();
    POSIX_ENSURE_REF(conn_config);
    POSIX_GUARD(s2n_read_test_pem_and_len(S2N_DEFAULT_TEST_CERT_CHAIN, cert_chain, &cert_chain_len, S2N_MAX_TEST_PEM_SIZE));
    POSIX_GUARD(s2n_read_test_pem_and_len(S2N_DEFAULT_TEST_PRIVATE_KEY, private_key, &private_key_len, S2N_MAX_TEST_PEM_SIZE));
    POSIX_GUARD(s2n_cert_chain_and_key_load_pem_bytes(default_cert, cert_chain, cert_chain_len, private_key, private_key_len));
    POSIX_GUARD(s2n_config_add_cert_chain_and_key_to_store(conn_config, default_cert));

    return S2N_SUCCESS;
}

int s2n_fuzz_test(const uint8_t *buf, size_t len)
{
    /* We need at least one byte of input to set parameters */
    S2N_FUZZ_ENSURE_MIN_LEN(len, 1);

    /* Setup */
    struct s2n_connection *conn = s2n_connection_new(S2N_SERVER);
    POSIX_ENSURE_REF(conn);
    POSIX_GUARD(s2n_connection_set_config(conn, conn_config));
    POSIX_GUARD(s2n_stuffer_write_bytes(&conn->handshake.io, buf, len));

    /* Pull a byte off the libfuzzer input and use it to set the connection mode */
    uint8_t randval = 0;
    POSIX_GUARD(s2n_stuffer_read_uint8(&conn->handshake.io, &randval));
    if (randval % 2) {
        conn->mode = S2N_CLIENT;
    }

    /* Run Test
     * Do not use GUARD macro here since the connection memory hasn't been freed.
     */
    s2n_tls13_cert_verify_recv(conn);

    /* Cleanup */
    POSIX_GUARD(s2n_connection_free(conn));

    return S2N_SUCCESS;
}

static void s2n_fuzz_cleanup()
{
    s2n_config_free(conn_config);
    free(cert_chain);
    free(private_key);
    s2n_cert_chain_and_key_free(default_cert);
}

S2N_FUZZ_TARGET(s2n_fuzz_init, s2n_fuzz_test, s2n_fuzz_cleanup)