/*
 * 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_test.h"
#include "testlib/s2n_testlib.h"

/* Included to test static function */
#include "tls/s2n_resume.c"

#define ARE_FULL_HANDSHAKES(client, server) \
    (IS_FULL_HANDSHAKE(client) && IS_FULL_HANDSHAKE(server))

#define IS_HELLO_RETRY(client, server)                          \
    (((client->handshake.handshake_type) & HELLO_RETRY_REQUEST) \
     && ((server->handshake.handshake_type) & HELLO_RETRY_REQUEST))

struct s2n_early_data_test_case {
    bool ticket_supported;
    bool client_supported;
    bool server_supported;
    bool expect_success;
};

static int s2n_test_session_ticket_cb(struct s2n_connection *conn, void *ctx, struct s2n_session_ticket *ticket)
{
    POSIX_ENSURE_REF(conn);
    POSIX_ENSURE_REF(ticket);

    size_t data_len = 0;
    EXPECT_SUCCESS(s2n_session_ticket_get_data_len(ticket, &data_len));

    struct s2n_stuffer *stuffer = (struct s2n_stuffer *) ctx;
    EXPECT_SUCCESS(s2n_stuffer_wipe(stuffer));
    EXPECT_SUCCESS(s2n_stuffer_resize(stuffer, data_len));
    EXPECT_SUCCESS(s2n_session_ticket_get_data(ticket, data_len, stuffer->blob.data));
    EXPECT_SUCCESS(s2n_stuffer_skip_write(stuffer, data_len));

    return S2N_SUCCESS;
}

static int s2n_setup_test_ticket_key(struct s2n_config *config)
{
    POSIX_ENSURE_REF(config);

    /**
     *= https://tools.ietf.org/rfc/rfc5869#appendix-A.1
     *# PRK  = 0x077709362c2e32df0ddc3f0dc47bba63
     *#        90b6c73bb50f9c3122ec844ad7c2b3e5 (32 octets)
     **/
    S2N_BLOB_FROM_HEX(ticket_key,
    "077709362c2e32df0ddc3f0dc47bba63"
    "90b6c73bb50f9c3122ec844ad7c2b3e5");

    /* Set up encryption key */
    uint64_t current_time = 0;
    uint8_t ticket_key_name[16] = "2016.07.26.15\0";
    EXPECT_SUCCESS(s2n_config_set_session_tickets_onoff(config, 1));
    EXPECT_SUCCESS(config->wall_clock(config->sys_clock_ctx, &current_time));
    EXPECT_SUCCESS(s2n_config_add_ticket_crypto_key(config, ticket_key_name, strlen((char *)ticket_key_name),
                    ticket_key.data, ticket_key.size, current_time/ONE_SEC_IN_NANOS));

    return S2N_SUCCESS;
}

static S2N_RESULT s2n_test_issue_new_session_ticket(struct s2n_connection *server_conn, struct s2n_connection *client_conn,
        const struct s2n_early_data_test_case *early_data_case)
{
    RESULT_ENSURE_REF(server_conn);
    RESULT_ENSURE_REF(client_conn);
    RESULT_ENSURE_REF(early_data_case);

    uint8_t data = 1;
    s2n_blocked_status blocked = S2N_NOT_BLOCKED;
    RESULT_GUARD_POSIX(s2n_connection_add_new_tickets_to_send(server_conn, 1));

    if (early_data_case->ticket_supported) {
        RESULT_GUARD_POSIX(s2n_connection_set_server_max_early_data_size(server_conn, UINT16_MAX));
    } else {
        RESULT_GUARD_POSIX(s2n_connection_set_server_max_early_data_size(server_conn, 0));
    }

    RESULT_ENSURE_NE(server_conn->tickets_to_send, server_conn->tickets_sent);
    RESULT_GUARD_POSIX(s2n_send(server_conn, &data, 1, &blocked));
    RESULT_GUARD_POSIX(s2n_recv(client_conn, &data, 1, &blocked));
    RESULT_ENSURE_EQ(server_conn->tickets_to_send, server_conn->tickets_sent);

    return S2N_RESULT_OK;
}

static S2N_RESULT s2n_test_negotiate(struct s2n_connection *server_conn, struct s2n_connection *client_conn,
        const struct s2n_early_data_test_case *early_data_case)
{
    RESULT_ENSURE_REF(server_conn);
    RESULT_ENSURE_REF(client_conn);
    RESULT_ENSURE_REF(early_data_case);

    uint8_t early_data[] = "very early hello world";
    uint8_t empty_data[sizeof(early_data)] = { 0 };

    uint8_t early_data_recv_data[sizeof(early_data)] = { 0 };
    struct s2n_blob early_data_recv = { 0 };
    RESULT_GUARD_POSIX(s2n_blob_init(&early_data_recv, early_data_recv_data, sizeof(early_data_recv_data)));

    if (early_data_case->server_supported) {
        RESULT_GUARD_POSIX(s2n_connection_set_server_max_early_data_size(server_conn, UINT16_MAX));
    } else {
        RESULT_GUARD_POSIX(s2n_connection_set_server_max_early_data_size(server_conn, 0));
    }

    struct s2n_blob early_data_send = { 0 };
    if (early_data_case->client_supported) {
        RESULT_GUARD_POSIX(s2n_blob_init(&early_data_send, early_data, sizeof(early_data)));
    }

    RESULT_GUARD(s2n_negotiate_test_server_and_client_with_early_data(server_conn, client_conn,
            &early_data_send, &early_data_recv));

    if (early_data_case->expect_success) {
        RESULT_ENSURE_EQ(early_data_recv.size, sizeof(early_data));
        EXPECT_BYTEARRAY_EQUAL(early_data_recv.data, early_data, sizeof(early_data));
    } else {
        RESULT_ENSURE_EQ(early_data_recv.size, sizeof(empty_data));
        EXPECT_BYTEARRAY_EQUAL(early_data_recv.data, empty_data, sizeof(empty_data));
    }

    return S2N_RESULT_OK;
}

int main(int argc, char **argv)
{
    BEGIN_TEST();

    /* For some session resumption test cases, we want to test all possible configurations of 0-RTT support. */
    size_t test_case_i = 0;
    struct s2n_early_data_test_case early_data_test_cases[ 2 * 2 * 2 ] = { 0 };
    for (size_t ticket_supported = 0; ticket_supported < 2; ticket_supported++) {
        early_data_test_cases[test_case_i].ticket_supported = ticket_supported;
        for (size_t client_supported = 0; client_supported < 2; client_supported++) {
            early_data_test_cases[test_case_i].client_supported = client_supported;
            for (size_t server_supported = 0; server_supported < 2; server_supported++) {
                early_data_test_cases[test_case_i].server_supported = server_supported;
                early_data_test_cases[test_case_i].expect_success = client_supported && server_supported && ticket_supported;
            }
        }
        test_case_i++;
    }
    /* For some session resumption test cases, we don't want to test or don't care about 0-RTT */
    const struct s2n_early_data_test_case no_early_data = { .client_supported = false, .server_supported = false,
            .expect_success = false };

    /* Setup server config */
    struct s2n_config *server_config = s2n_config_new();
    EXPECT_NOT_NULL(server_config);
    EXPECT_SUCCESS(s2n_config_set_cipher_preferences(server_config, "default_tls13"));
    EXPECT_SUCCESS(s2n_config_set_unsafe_for_testing(server_config));
    struct s2n_cert_chain_and_key *tls13_chain_and_key = NULL;
    EXPECT_SUCCESS(s2n_test_cert_chain_and_key_new(&tls13_chain_and_key, S2N_DEFAULT_ECDSA_TEST_CERT_CHAIN,
                                                   S2N_DEFAULT_ECDSA_TEST_PRIVATE_KEY));
    EXPECT_SUCCESS(s2n_config_add_cert_chain_and_key_to_store(server_config, tls13_chain_and_key));
    struct s2n_cert_chain_and_key *tls12_chain_and_key = NULL;
    EXPECT_SUCCESS(s2n_test_cert_chain_and_key_new(&tls12_chain_and_key, S2N_DEFAULT_TEST_CERT_CHAIN, 
                                                   S2N_DEFAULT_TEST_PRIVATE_KEY));
    EXPECT_SUCCESS(s2n_config_add_cert_chain_and_key_to_store(server_config, tls12_chain_and_key));
    EXPECT_SUCCESS(s2n_config_set_session_tickets_onoff(server_config, true));
    EXPECT_SUCCESS(s2n_setup_test_ticket_key(server_config));

    /* Setup TLS1.3 client config */
    struct s2n_config *tls13_client_config = s2n_config_new();
    EXPECT_NOT_NULL(tls13_client_config);
    EXPECT_SUCCESS(s2n_config_set_cipher_preferences(tls13_client_config, "default_tls13"));
    EXPECT_SUCCESS(s2n_config_set_unsafe_for_testing(tls13_client_config));
    EXPECT_SUCCESS(s2n_config_set_session_tickets_onoff(tls13_client_config, true));
    DEFER_CLEANUP(struct s2n_stuffer cb_session_data = { 0 }, s2n_stuffer_free);
    EXPECT_SUCCESS(s2n_stuffer_growable_alloc(&cb_session_data, 0));
    EXPECT_SUCCESS(s2n_config_set_session_ticket_cb(tls13_client_config, s2n_test_session_ticket_cb, &cb_session_data));

    /* Setup TLS1.2 client config */
    struct s2n_config *tls12_client_config = s2n_config_new();
    EXPECT_NOT_NULL(tls12_client_config);
    EXPECT_SUCCESS(s2n_config_set_cipher_preferences(tls12_client_config, "20170210"));
    EXPECT_SUCCESS(s2n_config_set_unsafe_for_testing(tls12_client_config));
    EXPECT_SUCCESS(s2n_config_set_session_tickets_onoff(tls12_client_config, true));

    /* Test: Server and client resume a session multiple times */
    for (size_t early_data_i = 0; early_data_i < s2n_array_len(early_data_test_cases); early_data_i++) {
        const struct s2n_early_data_test_case early_data_case = early_data_test_cases[early_data_i];

        struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
        struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
        EXPECT_NOT_NULL(client_conn);
        EXPECT_NOT_NULL(server_conn);

        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));
        EXPECT_SUCCESS(s2n_connection_set_config(server_conn, server_config));

        /* Create nonblocking pipes */
        struct s2n_test_io_pair io_pair = { 0 };
        EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Negotiate initial handshake */
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));

        /* Receive and save the issued session ticket for the next connection */
        EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &early_data_case));

        for (size_t i = 0; i < 10; i++) {
            /* Prepare client and server for new connection */
            EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
            EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
            EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
            EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

            /* Client sets up a resumption connection with the received session ticket data */
            size_t cb_session_data_len = s2n_stuffer_data_available(&cb_session_data);
            EXPECT_SUCCESS(s2n_connection_set_session(client_conn, cb_session_data.blob.data, cb_session_data_len));
            EXPECT_SUCCESS(s2n_stuffer_rewrite(&cb_session_data));

            /* Negotiate new connection */
            EXPECT_OK(s2n_test_negotiate(server_conn, client_conn, &early_data_case));
            EXPECT_FALSE(ARE_FULL_HANDSHAKES(client_conn, server_conn));

            /* Verify we can free the handshakes */
            EXPECT_SUCCESS(s2n_connection_free_handshake(client_conn));
            EXPECT_SUCCESS(s2n_connection_free_handshake(server_conn));

            /* Receive and save the issued session ticket for the next connection */
            EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &early_data_case));
        }

        EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
        EXPECT_SUCCESS(s2n_connection_free(server_conn));
        EXPECT_SUCCESS(s2n_connection_free(client_conn));
        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
        EXPECT_SUCCESS(s2n_stuffer_rewrite(&cb_session_data));
    }

    /* Test: Server does not accept an expired ticket and instead does a full handshake */
    {
        struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
        struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
        EXPECT_NOT_NULL(client_conn);
        EXPECT_NOT_NULL(server_conn);

        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));
        EXPECT_SUCCESS(s2n_connection_set_config(server_conn, server_config));

        /* Create nonblocking pipes */
        struct s2n_test_io_pair io_pair = { 0 };
        EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Negotiate initial handshake */
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));

        /* Receive and save the issued session ticket for the next connection */
        EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &no_early_data));

        /* Prepare client and server for new connection */
        EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Client sets up a resumption connection with the received session ticket data */
        size_t cb_session_data_len = s2n_stuffer_data_available(&cb_session_data);
        EXPECT_SUCCESS(s2n_connection_set_session(client_conn, cb_session_data.blob.data, cb_session_data_len));
        EXPECT_SUCCESS(s2n_stuffer_rewrite(&cb_session_data));

        /* Setup conditions to make the server think the ticket has expired */
        EXPECT_SUCCESS(s2n_config_set_session_state_lifetime(server_config, 0));

        /* Negotiate new connection */
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));

        EXPECT_SUCCESS(s2n_connection_free(server_conn));
        EXPECT_SUCCESS(s2n_connection_free(client_conn));
        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
        EXPECT_SUCCESS(s2n_stuffer_rewrite(&cb_session_data));
        EXPECT_SUCCESS(s2n_config_set_session_state_lifetime(server_config, S2N_STATE_LIFETIME_IN_NANOS));
    }

    /* Test: A TLS1.2 client with a valid TLS1.3 ticket falls back to a TLS1.2 connection */
    for (size_t early_data_i = 0; early_data_i < s2n_array_len(early_data_test_cases); early_data_i++) {
        struct s2n_early_data_test_case early_data_case = early_data_test_cases[early_data_i];
        /* Early data is never sent in TLS1.2 (or in a full handshake) */
        early_data_case.expect_success = false;

        struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
        struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
        EXPECT_NOT_NULL(client_conn);
        EXPECT_NOT_NULL(server_conn);

        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));
        EXPECT_SUCCESS(s2n_connection_set_config(server_conn, server_config));

        /* Create nonblocking pipes */
        struct s2n_test_io_pair io_pair = { 0 };
        EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Negotiate initial handshake */
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));

        /* Receive and save the issued session ticket for the next connection */
        EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &early_data_case));

        /* Prepare client and server for a second connection */
        EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Client sets up a resumption connection with the received session ticket data */
        size_t cb_session_data_len = s2n_stuffer_data_available(&cb_session_data);
        EXPECT_SUCCESS(s2n_connection_set_session(client_conn, cb_session_data.blob.data, cb_session_data_len));
        EXPECT_SUCCESS(s2n_stuffer_rewrite(&cb_session_data));

        /* Set client config to TLS1.2 cipher preferences */
        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls12_client_config));

        /* Negotiate second connection */
        EXPECT_OK(s2n_test_negotiate(server_conn, client_conn, &early_data_case));

        /* Falls back to TLS1.2 handshake */
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));
        EXPECT_EQUAL(client_conn->actual_protocol_version, S2N_TLS12);
        EXPECT_EQUAL(server_conn->actual_protocol_version, S2N_TLS12);

        EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
        EXPECT_SUCCESS(s2n_connection_free(server_conn));
        EXPECT_SUCCESS(s2n_connection_free(client_conn));
        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
    }

    /* Test: A client with a valid TLS1.2 session ticket and TLS1.3 cipher preferences
     * will fail connecting to a TLS1.3 server. This is because the server
     * interprets the client as a TLS1.2 client and sends the client a TLS1.2 Server Hello.
     * The client receives this TLS1.2 Server Hello and errors, because the client 
     * views the TLS1.2 Server Hello as a downgrade attack, given that the client advertised
     * its TLS1.3 ability in the Client Hello.
     */
    {
        struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
        struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
        EXPECT_NOT_NULL(client_conn);
        EXPECT_NOT_NULL(server_conn);

        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls12_client_config));
        EXPECT_SUCCESS(s2n_connection_set_config(server_conn, server_config));

        /* Create nonblocking pipes */
        struct s2n_test_io_pair io_pair = { 0 };
        EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Negotiate initial handshake to produce TLS1.2 session ticket */
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));
        EXPECT_TRUE(IS_ISSUING_NEW_SESSION_TICKET(server_conn));

        /* Store the TLS1.2 session ticket */
        size_t tls12_session_ticket_len = s2n_connection_get_session_length(client_conn);
        uint8_t tls12_session_ticket[S2N_TLS12_SESSION_SIZE] = { 0 };
        EXPECT_SUCCESS(s2n_connection_get_session(client_conn, tls12_session_ticket, tls12_session_ticket_len));

        /* Prepare client and server for a second connection */
        EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
        EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));

        /* Client sets up a resumption connection with the received TLS1.2 session ticket data */
        EXPECT_SUCCESS(s2n_connection_set_session(client_conn, tls12_session_ticket, tls12_session_ticket_len));

        /* Set client config to TLS1.3 cipher preferences */
        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));

        /* Negotiate second connection */
        EXPECT_FAILURE_WITH_ERRNO(s2n_negotiate_test_server_and_client(server_conn, client_conn), S2N_ERR_PROTOCOL_DOWNGRADE_DETECTED);

        EXPECT_SUCCESS(s2n_connection_free(server_conn));
        EXPECT_SUCCESS(s2n_connection_free(client_conn));
        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
    }

    /* HRR when issuing a session resumption ticket and when resuming a session */
    for (size_t early_data_i = 0; early_data_i < s2n_array_len(early_data_test_cases); early_data_i++) {
        struct s2n_early_data_test_case early_data_case = early_data_test_cases[early_data_i];
        /* Never use early data on a HRR */
        early_data_case.expect_success = false;

        struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
        struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
        EXPECT_NOT_NULL(client_conn);
        EXPECT_NOT_NULL(server_conn);

        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));
        EXPECT_SUCCESS(s2n_connection_set_config(server_conn, server_config));
        client_conn->security_policy_override = &security_policy_test_tls13_retry;

        /* Create nonblocking pipes */
        struct s2n_test_io_pair io_pair = { 0 };
        EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Negotiate handshake */
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));

        /* Validate handshake type */
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));
        EXPECT_TRUE(IS_HELLO_RETRY(client_conn, server_conn));

        /* Receive and save the issued session ticket for the next connection */
        EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &early_data_case));

        /* Prepare client and server for new connection */
        EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
        client_conn->security_policy_override = &security_policy_test_tls13_retry;

        /* Client sets up a resumption connection with the received session ticket data */
        size_t cb_session_data_len = s2n_stuffer_data_available(&cb_session_data);
        EXPECT_SUCCESS(s2n_connection_set_session(client_conn, cb_session_data.blob.data, cb_session_data_len));
        EXPECT_SUCCESS(s2n_stuffer_rewrite(&cb_session_data));

        /* Negotiate new connection */
        EXPECT_OK(s2n_test_negotiate(server_conn, client_conn, &early_data_case));
        EXPECT_FALSE(ARE_FULL_HANDSHAKES(client_conn, server_conn));
        EXPECT_TRUE(IS_HELLO_RETRY(client_conn, server_conn));

        EXPECT_SUCCESS(s2n_connection_free(server_conn));
        EXPECT_SUCCESS(s2n_connection_free(client_conn));
        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
    }

    /* Test: reuse a connection for both TLS1.2 and TLS1.3 session resumption.
     *
     * TLS1.2 and TLS1.3 reuse some of the same code / memory. We should verify that using
     * one doesn't affect our ability to use the other after wiping the connection.
     */
    {
        struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
        EXPECT_NOT_NULL(client_conn);

        struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
        EXPECT_NOT_NULL(server_conn);
        EXPECT_SUCCESS(s2n_connection_set_config(server_conn, server_config));

        /* Create nonblocking pipes */
        struct s2n_test_io_pair io_pair = { 0 };
        EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        DEFER_CLEANUP(struct s2n_stuffer tls12_ticket = { 0 }, s2n_stuffer_free);
        DEFER_CLEANUP(struct s2n_stuffer tls13_ticket = { 0 }, s2n_stuffer_free);
        EXPECT_SUCCESS(s2n_stuffer_growable_alloc(&tls12_ticket, 0));
        EXPECT_SUCCESS(s2n_stuffer_growable_alloc(&tls13_ticket, 0));

        /* Negotiate initial TLS1.3 handshake */
        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));
        EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &no_early_data));
        EXPECT_SUCCESS(s2n_stuffer_copy(&cb_session_data, &tls13_ticket, s2n_stuffer_data_available(&cb_session_data)));

        /* Prepare client and server for a second connection */
        EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Negotiate initial TLS1.2 handshake */
        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls12_client_config));
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        EXPECT_TRUE(ARE_FULL_HANDSHAKES(client_conn, server_conn));
        int tls12_ticket_length = s2n_connection_get_session_length(client_conn);
        EXPECT_SUCCESS(s2n_stuffer_skip_write(&tls12_ticket, tls12_ticket_length));
        EXPECT_SUCCESS(s2n_connection_get_session(client_conn, tls12_ticket.blob.data, tls12_ticket_length));

        /* Switch between TLS1.2 and TLS1.3 resumption */
        for (size_t i = 0; i < 10; i++) {
            EXPECT_SUCCESS(s2n_shutdown_test_server_and_client(server_conn, client_conn));
            EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
            EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
            EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

            bool do_tls13 = (i % 2 == 0);

            uint8_t expected_version = 0;
            if (do_tls13) {
                expected_version = S2N_TLS13;
                EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));
                EXPECT_SUCCESS(s2n_connection_set_session(client_conn, tls13_ticket.blob.data,
                        s2n_stuffer_data_available(&tls13_ticket)));
            } else {
                expected_version = S2N_TLS12;
                EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls12_client_config));
                EXPECT_SUCCESS(s2n_connection_set_session(client_conn, tls12_ticket.blob.data,
                        s2n_stuffer_data_available(&tls12_ticket)));
            }

            EXPECT_OK(s2n_test_negotiate(server_conn, client_conn, &no_early_data));
            EXPECT_FALSE(ARE_FULL_HANDSHAKES(client_conn, server_conn));
            EXPECT_EQUAL(client_conn->actual_protocol_version, expected_version);
            EXPECT_EQUAL(server_conn->actual_protocol_version, expected_version);

            if (do_tls13) {
                EXPECT_SUCCESS(s2n_stuffer_wipe(&tls13_ticket));
                EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &no_early_data));
                EXPECT_SUCCESS(s2n_stuffer_copy(&cb_session_data, &tls13_ticket, s2n_stuffer_data_available(&cb_session_data)));
            } else {
                EXPECT_SUCCESS(s2n_stuffer_wipe(&tls12_ticket));
                tls12_ticket_length = s2n_connection_get_session_length(client_conn);
                EXPECT_SUCCESS(s2n_stuffer_skip_write(&tls12_ticket, tls12_ticket_length));
                EXPECT_SUCCESS(s2n_connection_get_session(client_conn, tls12_ticket.blob.data, tls12_ticket_length));
            }
        }

        EXPECT_SUCCESS(s2n_connection_free(server_conn));
        EXPECT_SUCCESS(s2n_connection_free(client_conn));
        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
    }

    /* Test output of s2n_connection_get_session_length/get_session during different stages of the handshake */
    {
        struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
        EXPECT_NOT_NULL(client_conn);

        struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
        EXPECT_NOT_NULL(server_conn);
        EXPECT_SUCCESS(s2n_connection_set_config(server_conn, server_config));

        /* Create nonblocking pipes */
        struct s2n_test_io_pair io_pair = { 0 };
        EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        DEFER_CLEANUP(struct s2n_stuffer tls12_ticket = { 0 }, s2n_stuffer_free);
        DEFER_CLEANUP(struct s2n_stuffer tls13_ticket = { 0 }, s2n_stuffer_free);
        EXPECT_SUCCESS(s2n_stuffer_growable_alloc(&tls12_ticket, 0));
        EXPECT_SUCCESS(s2n_stuffer_growable_alloc(&tls13_ticket, 0));

        /* Negotiate initial TLS1.3 handshake */
        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &no_early_data));
        EXPECT_SUCCESS(s2n_stuffer_copy(&cb_session_data, &tls13_ticket, s2n_stuffer_data_available(&cb_session_data)));

        /* Prepare client and server for a second connection */
        EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
        EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        /* Negotiate initial TLS1.2 handshake */
        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls12_client_config));
        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
        int tls12_ticket_length = s2n_connection_get_session_length(client_conn);
        EXPECT_SUCCESS(s2n_stuffer_skip_write(&tls12_ticket, tls12_ticket_length));
        EXPECT_SUCCESS(s2n_connection_get_session(client_conn, tls12_ticket.blob.data, tls12_ticket_length));

        struct s2n_config *client_config[] = { tls12_client_config, tls13_client_config };
        DEFER_CLEANUP(struct s2n_blob session_state = { 0 }, s2n_free);

        /* A quirk of the TLS1.2 session resumption behavior is that if a ticket is set
         * on the connection using s2n_connection_set_session, s2n_connection_get_session 
         * will return a valid ticket, even before actually receiving a new session ticket
         * from the server. Here we test that behavior to ensure it is consistent. */
        for (size_t j = 0; j < s2n_array_len(client_config); j++) {
            /* Prepare client and server for new connection */
            EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
            EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
            EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

            EXPECT_SUCCESS(s2n_connection_set_config(client_conn, client_config[j]));

            /* Client sets up a resumption connection with the received session ticket data */
            EXPECT_SUCCESS(s2n_connection_set_session(client_conn, tls12_ticket.blob.data, s2n_stuffer_data_available(&tls12_ticket)));

            /* s2n_connection_get_session will be non-zero if a TLS1.2 ticket was set on the connection */
            uint32_t session_length = s2n_connection_get_session_length(client_conn);
            EXPECT_TRUE(session_length > 0);

            EXPECT_SUCCESS(s2n_realloc(&session_state, session_length));

            /* Call get_session to retrieve session ticket */
            EXPECT_SUCCESS(s2n_connection_get_session(client_conn, session_state.data, session_length));

            /* Check that the session ticket returned is valid by deserializing it */
            struct s2n_stuffer session_state_stuffer = { 0 };
            EXPECT_SUCCESS(s2n_stuffer_init(&session_state_stuffer, &session_state));
            EXPECT_SUCCESS(s2n_stuffer_skip_write(&session_state_stuffer, session_length));
            EXPECT_SUCCESS(s2n_client_deserialize_resumption_state(client_conn, &session_state_stuffer));

            /* A TLS1.2 ticket set on a TLS1.3 connection will cause a downgrade error during negotiation,
             * as seen in an earlier test */
            if (client_config[j] == tls13_client_config) {
                continue;
            }

            /* Negotiate TLS1.2 connection */
            EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));

            /* The session length should be non-zero after a client has received a session ticket */
            EXPECT_TRUE(s2n_connection_get_session_length(client_conn) > 0);
        }

        /* Tests that if a TLS1.3 ticket is set on the connection, s2n_connection_get_session will
         * not return a ticket until a session ticket is sent by the server as a post-handshake
         * message. */
        for (size_t j = 0; j < s2n_array_len(client_config); j++) {
            /* Prepare client and server for new connection */
            EXPECT_SUCCESS(s2n_connection_wipe(client_conn));
            EXPECT_SUCCESS(s2n_connection_wipe(server_conn));
            EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

            EXPECT_SUCCESS(s2n_connection_set_config(client_conn, client_config[j]));

            /* Client sets up a resumption connection with the received session ticket data */
            EXPECT_SUCCESS(s2n_connection_set_session(client_conn, tls13_ticket.blob.data, s2n_stuffer_data_available(&tls13_ticket)));

            /* s2n_connection_get_session will be zero before receiving a session ticket
            * if a TLS1.3 ticket was set on the connection. */
            EXPECT_EQUAL(s2n_connection_get_session_length(client_conn), 0);

            EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));

            if (client_conn->actual_protocol_version < S2N_TLS13) {
                EXPECT_TRUE(s2n_connection_get_session_length(client_conn) > 0);
            } else {
                /* The session length should be zero before a client has received a session ticket */
                EXPECT_EQUAL(s2n_connection_get_session_length(client_conn), 0);

                /* Receive the issued TLS1.3 session ticket */
                EXPECT_OK(s2n_test_issue_new_session_ticket(server_conn, client_conn, &no_early_data));

                /* The session length should be non-zero after a client has received a session ticket */
                EXPECT_TRUE(s2n_connection_get_session_length(client_conn) > 0);
            }
        }
        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
        EXPECT_SUCCESS(s2n_connection_free(server_conn));
        EXPECT_SUCCESS(s2n_connection_free(client_conn));
    }

    /* If the server has no ticket key, no session ticket is issued. */
    {
        struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
        EXPECT_NOT_NULL(client_conn);

        struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
        EXPECT_NOT_NULL(server_conn);

        /* Setup config without session ticket key */
        struct s2n_config *no_key_config = s2n_config_new();
        EXPECT_NOT_NULL(no_key_config);
        EXPECT_SUCCESS(s2n_config_set_cipher_preferences(no_key_config, "default_tls13"));
        EXPECT_SUCCESS(s2n_config_set_unsafe_for_testing(no_key_config));
        EXPECT_SUCCESS(s2n_config_add_cert_chain_and_key_to_store(no_key_config, tls13_chain_and_key));
        EXPECT_SUCCESS(s2n_config_add_cert_chain_and_key_to_store(no_key_config, tls12_chain_and_key));
        EXPECT_SUCCESS(s2n_config_set_session_tickets_onoff(no_key_config, true));

        EXPECT_SUCCESS(s2n_connection_set_config(server_conn, no_key_config));
        EXPECT_SUCCESS(s2n_connection_set_config(client_conn, tls13_client_config));

        /* Create nonblocking pipes */
        struct s2n_test_io_pair io_pair = { 0 };
        EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
        EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));

        EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));

        /* Server never sent a ticket to the client */
        EXPECT_EQUAL(s2n_connection_get_session_length(client_conn), 0);

        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
        EXPECT_SUCCESS(s2n_config_free(no_key_config));
        EXPECT_SUCCESS(s2n_connection_free(server_conn));
        EXPECT_SUCCESS(s2n_connection_free(client_conn));
    }

    /* Clean-up */
    EXPECT_SUCCESS(s2n_config_free(server_config));
    EXPECT_SUCCESS(s2n_config_free(tls13_client_config));
    EXPECT_SUCCESS(s2n_config_free(tls12_client_config));
    EXPECT_SUCCESS(s2n_cert_chain_and_key_free(tls13_chain_and_key));
    EXPECT_SUCCESS(s2n_cert_chain_and_key_free(tls12_chain_and_key));

    END_TEST();
}