#! /usr/bin/env perl

# Copyright 2017-2018 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

use strict;

use OpenSSL::Test qw/:DEFAULT cmdstr srctop_file bldtop_dir/;

use OpenSSL::Test::Utils;

use TLSProxy::Proxy;

my $test_name = "test_tls13downgrade";

setup($test_name);

plan skip_all => "TLSProxy isn't usable on $^O"

    if $^O =~ /^(VMS)$/;

plan skip_all => "$test_name needs the dynamic engine feature enabled"

    if disabled("engine") || disabled("dynamic-engine");

plan skip_all => "$test_name needs the sock feature enabled"

    if disabled("sock");

plan skip_all => "$test_name needs TLS1.3 and TLS1.2 enabled"

    if disabled("tls1_3") || disabled("tls1_2");

$ENV{OPENSSL_ia32cap} = '~0x200000200000000';

my $proxy = TLSProxy::Proxy->new(

    undef,

    cmdstr(app(["openssl"]), display => 1),

    srctop_file("apps", "server.pem"),

    (!$ENV{HARNESS_ACTIVE} || $ENV{HARNESS_VERBOSE})

);

use constant {

    DOWNGRADE_TO_TLS_1_2 => 0,

    DOWNGRADE_TO_TLS_1_1 => 1,

    FALLBACK_FROM_TLS_1_3 => 2,

};

#Test 1: Downgrade from TLSv1.3 to TLSv1.2

$proxy->filter(\&downgrade_filter);

my $testtype = DOWNGRADE_TO_TLS_1_2;

$proxy->start() or plan skip_all => "Unable to start up Proxy for tests";

plan tests => 6;

ok(TLSProxy::Message->fail(), "Downgrade TLSv1.3 to TLSv1.2");

#Test 2: Downgrade from TLSv1.3 to TLSv1.1

$proxy->clear();

$testtype = DOWNGRADE_TO_TLS_1_1;

$proxy->start();

ok(TLSProxy::Message->fail(), "Downgrade TLSv1.3 to TLSv1.1");

#Test 3: Downgrade from TLSv1.2 to TLSv1.1

$proxy->clear();

$proxy->clientflags("-no_tls1_3");

$proxy->serverflags("-no_tls1_3");

$proxy->start();

ok(TLSProxy::Message->fail(), "Downgrade TLSv1.2 to TLSv1.1");

#Test 4: Client falls back from TLSv1.3 (server does not support the fallback

#        SCSV)

$proxy->clear();

$testtype = FALLBACK_FROM_TLS_1_3;

$proxy->clientflags("-fallback_scsv -no_tls1_3");

$proxy->start();

my $alert = TLSProxy::Message->alert();

ok(TLSProxy::Message->fail()

   && !$alert->server()

   && $alert->description() == TLSProxy::Message::AL_DESC_ILLEGAL_PARAMETER,

   "Fallback from TLSv1.3");

SKIP: {

    skip "TLSv1.1 disabled", 2 if disabled("tls1_1");

    #Test 5: A client side protocol "hole" should not be detected as a downgrade

    $proxy->clear();

    $proxy->filter(undef);

    $proxy->clientflags("-no_tls1_2");

    $proxy->start();

    ok(TLSProxy::Message->success(), "TLSv1.2 client-side protocol hole");

    #Test 6: A server side protocol "hole" should not be detected as a downgrade

    $proxy->clear();

    $proxy->filter(undef);

    $proxy->serverflags("-no_tls1_2");

    $proxy->start();

    ok(TLSProxy::Message->success(), "TLSv1.2 server-side protocol hole");

}

sub downgrade_filter

{

    my $proxy = shift;

    # We're only interested in the initial ClientHello

    if ($proxy->flight != 0) {

        return;

    }

    my $message = ${$proxy->message_list}[0];

    my $ext;

    if ($testtype == FALLBACK_FROM_TLS_1_3) {

        #The default ciphersuite we use for TLSv1.2 without any SCSV

        my @ciphersuites = (TLSProxy::Message::CIPHER_RSA_WITH_AES_128_CBC_SHA);

        $message->ciphersuite_len(2 * scalar @ciphersuites);

        $message->ciphersuites(\@ciphersuites);

    } else {

        if ($testtype == DOWNGRADE_TO_TLS_1_2) {

            $ext = pack "C3",

                0x02, # Length

                0x03, 0x03; #TLSv1.2

        } else {

            $ext = pack "C3",

                0x02, # Length

                0x03, 0x02; #TLSv1.1

        }

        $message->set_extension(TLSProxy::Message::EXT_SUPPORTED_VERSIONS, $ext);

    }

    $message->repack();

}