/*

 * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include <string.h>

#include <openssl/dtls1.h>

#include <openssl/ssl.h>

#include <openssl/err.h>

#include "ssltestlib.h"

#include "testutil.h"

/* for SSL_READ_ETM() */

#include "../ssl/ssl_local.h"

static int debug = 0;

static unsigned int clnt_psk_callback(SSL *ssl, const char *hint,

                                      char *ident, unsigned int max_ident_len,

                                      unsigned char *psk,

                                      unsigned int max_psk_len)

{

    BIO_snprintf(ident, max_ident_len, "psk");

    if (max_psk_len > 20)

        max_psk_len = 20;

    memset(psk, 0x5a, max_psk_len);

    return max_psk_len;

}

static unsigned int srvr_psk_callback(SSL *ssl, const char *identity,

                                      unsigned char *psk,

                                      unsigned int max_psk_len)

{

    if (max_psk_len > 20)

        max_psk_len = 20;

    memset(psk, 0x5a, max_psk_len);

    return max_psk_len;

}

static int mtu_test(SSL_CTX *ctx, const char *cs, int no_etm)

{

    SSL *srvr_ssl = NULL, *clnt_ssl = NULL;

    BIO *sc_bio = NULL;

    int i;

    size_t s;

    size_t mtus[30];

    unsigned char buf[600];

    int rv = 0;

    memset(buf, 0x5a, sizeof(buf));

    if (!TEST_true(create_ssl_objects(ctx, ctx, &srvr_ssl, &clnt_ssl,

                                      NULL, NULL)))

        goto end;

    if (no_etm)

        SSL_set_options(srvr_ssl, SSL_OP_NO_ENCRYPT_THEN_MAC);

    if (!TEST_true(SSL_set_cipher_list(srvr_ssl, cs))

            || !TEST_true(SSL_set_cipher_list(clnt_ssl, cs))

            || !TEST_ptr(sc_bio = SSL_get_rbio(srvr_ssl))

            || !TEST_true(create_ssl_connection(clnt_ssl, srvr_ssl,

                                                SSL_ERROR_NONE)))

        goto end;

    if (debug)

        TEST_info("Channel established");

    /* For record MTU values between 500 and 539, call DTLS_get_data_mtu()

     * to query the payload MTU which will fit. */

    for (i = 0; i < 30; i++) {

        SSL_set_mtu(clnt_ssl, 500 + i);

        mtus[i] = DTLS_get_data_mtu(clnt_ssl);

        if (debug)

            TEST_info("%s%s MTU for record mtu %d = %lu",

                      cs, no_etm ? "-noEtM" : "",

                      500 + i, (unsigned long)mtus[i]);

        if (!TEST_size_t_ne(mtus[i], 0)) {

            TEST_info("Cipher %s MTU %d", cs, 500 + i);

            goto end;

        }

    }

    /* Now get out of the way */

    SSL_set_mtu(clnt_ssl, 1000);

    /*

     * Now for all values in the range of payload MTUs, send a payload of

     * that size and see what actual record size we end up with.

     */

    for (s = mtus[0]; s <= mtus[29]; s++) {

        size_t reclen;

        if (!TEST_int_eq(SSL_write(clnt_ssl, buf, s), (int)s))

            goto end;

        reclen = BIO_read(sc_bio, buf, sizeof(buf));

        if (debug)

            TEST_info("record %zu for payload %zu", reclen, s);

        for (i = 0; i < 30; i++) {

            /* DTLS_get_data_mtu() with record MTU 500+i returned mtus[i] ... */

            if (!TEST_false(s <= mtus[i] && reclen > (size_t)(500 + i))) {

                /*

                 * We sent a packet smaller than or equal to mtus[j] and

                 * that made a record *larger* than the record MTU 500+j!

                 */

                TEST_error("%s: s=%lu, mtus[i]=%lu, reclen=%lu, i=%d",

                           cs, (unsigned long)s, (unsigned long)mtus[i],

                           (unsigned long)reclen, 500 + i);

                goto end;

            }

            if (!TEST_false(s > mtus[i] && reclen <= (size_t)(500 + i))) {

                /*

                 * We sent a *larger* packet than mtus[i] and that *still*

                 * fits within the record MTU 500+i, so DTLS_get_data_mtu()

                 * was overly pessimistic.

                 */

                TEST_error("%s: s=%lu, mtus[i]=%lu, reclen=%lu, i=%d",

                           cs, (unsigned long)s, (unsigned long)mtus[i],

                           (unsigned long)reclen, 500 + i);

                goto end;

            }

        }

    }

    rv = 1;

    if (SSL_READ_ETM(clnt_ssl))

        rv = 2;

 end:

    SSL_free(clnt_ssl);

    SSL_free(srvr_ssl);

    return rv;

}

static int run_mtu_tests(void)

{

    SSL_CTX *ctx = NULL;

    STACK_OF(SSL_CIPHER) *ciphers;

    int i, ret = 0;

    if (!TEST_ptr(ctx = SSL_CTX_new(DTLS_method())))

        goto end;

    SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);

    SSL_CTX_set_psk_client_callback(ctx, clnt_psk_callback);

    SSL_CTX_set_security_level(ctx, 0);

    /*

     * We only care about iterating over each enc/mac; we don't want to

     * repeat the test for each auth/kx variant. So keep life simple and

     * only do (non-DH) PSK.

     */

    if (!TEST_true(SSL_CTX_set_cipher_list(ctx, "PSK")))

        goto end;

    ciphers = SSL_CTX_get_ciphers(ctx);

    for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {

        const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(ciphers, i);

        const char *cipher_name = SSL_CIPHER_get_name(cipher);

        /* As noted above, only one test for each enc/mac variant. */

        if (strncmp(cipher_name, "PSK-", 4) != 0)

            continue;

        if (!TEST_int_gt(ret = mtu_test(ctx, cipher_name, 0), 0))

            break;

        TEST_info("%s OK", cipher_name);

        if (ret == 1)

            continue;

        /* mtu_test() returns 2 if it used Encrypt-then-MAC */

        if (!TEST_int_gt(ret = mtu_test(ctx, cipher_name, 1), 0))

            break;

        TEST_info("%s without EtM OK", cipher_name);

    }

 end:

    SSL_CTX_free(ctx);

    bio_s_mempacket_test_free();

    return ret;

}

int setup_tests(void)

{

    ADD_TEST(run_mtu_tests);

    return 1;

}