1#! /usr/bin/env perl 2# Copyright 2017-2021 The OpenSSL Project Authors. All Rights Reserved. 3# 4# Licensed under the Apache License 2.0 (the "License"). You may not use 5# this file except in compliance with the License. You can obtain a copy 6# in the file LICENSE in the source distribution or at 7# https://www.openssl.org/source/license.html 8 9use strict; 10use OpenSSL::Test qw/:DEFAULT cmdstr srctop_file bldtop_dir/; 11use OpenSSL::Test::Utils; 12use TLSProxy::Proxy; 13 14my $test_name = "test_tls13downgrade"; 15setup($test_name); 16 17plan skip_all => "TLSProxy isn't usable on $^O" 18 if $^O =~ /^(VMS)$/; 19 20plan skip_all => "$test_name needs the dynamic engine feature enabled" 21 if disabled("engine") || disabled("dynamic-engine"); 22 23plan skip_all => "$test_name needs the sock feature enabled" 24 if disabled("sock"); 25 26plan skip_all => "$test_name needs TLS1.3 and TLS1.2 enabled" 27 if disabled("tls1_3") 28 || (disabled("ec") && disabled("dh")) 29 || disabled("tls1_2"); 30 31$ENV{OPENSSL_ia32cap} = '~0x200000200000000'; 32 33my $proxy = TLSProxy::Proxy->new( 34 undef, 35 cmdstr(app(["openssl"]), display => 1), 36 srctop_file("apps", "server.pem"), 37 (!$ENV{HARNESS_ACTIVE} || $ENV{HARNESS_VERBOSE}) 38); 39 40use constant { 41 DOWNGRADE_TO_TLS_1_2 => 0, 42 DOWNGRADE_TO_TLS_1_1 => 1, 43 FALLBACK_FROM_TLS_1_3 => 2, 44}; 45 46#Test 1: Downgrade from TLSv1.3 to TLSv1.2 47$proxy->filter(\&downgrade_filter); 48my $testtype = DOWNGRADE_TO_TLS_1_2; 49$proxy->start() or plan skip_all => "Unable to start up Proxy for tests"; 50plan tests => 6; 51ok(TLSProxy::Message->fail(), "Downgrade TLSv1.3 to TLSv1.2"); 52 53#Test 2: Downgrade from TLSv1.3 to TLSv1.1 54$proxy->clear(); 55$testtype = DOWNGRADE_TO_TLS_1_1; 56$proxy->start(); 57ok(TLSProxy::Message->fail(), "Downgrade TLSv1.3 to TLSv1.1"); 58 59#Test 3: Downgrade from TLSv1.2 to TLSv1.1 60$proxy->clear(); 61$proxy->clientflags("-no_tls1_3"); 62$proxy->serverflags("-no_tls1_3"); 63$proxy->start(); 64ok(TLSProxy::Message->fail(), "Downgrade TLSv1.2 to TLSv1.1"); 65 66#Test 4: Client falls back from TLSv1.3 (server does not support the fallback 67# SCSV) 68$proxy->clear(); 69$testtype = FALLBACK_FROM_TLS_1_3; 70$proxy->clientflags("-fallback_scsv -no_tls1_3"); 71$proxy->start(); 72my $alert = TLSProxy::Message->alert(); 73ok(TLSProxy::Message->fail() 74 && !$alert->server() 75 && $alert->description() == TLSProxy::Message::AL_DESC_ILLEGAL_PARAMETER, 76 "Fallback from TLSv1.3"); 77 78SKIP: { 79 skip "TLSv1.1 disabled", 2 if disabled("tls1_1"); 80 #Test 5: A client side protocol "hole" should not be detected as a downgrade 81 $proxy->clear(); 82 $proxy->filter(undef); 83 $proxy->clientflags("-no_tls1_2"); 84 $proxy->ciphers("AES128-SHA:\@SECLEVEL=0"); 85 $proxy->start(); 86 ok(TLSProxy::Message->success(), "TLSv1.2 client-side protocol hole"); 87 88 #Test 6: A server side protocol "hole" should not be detected as a downgrade 89 $proxy->clear(); 90 $proxy->filter(undef); 91 $proxy->serverflags("-no_tls1_2"); 92 $proxy->start(); 93 ok(TLSProxy::Message->success(), "TLSv1.2 server-side protocol hole"); 94} 95 96sub downgrade_filter 97{ 98 my $proxy = shift; 99 100 # We're only interested in the initial ClientHello 101 if ($proxy->flight != 0) { 102 return; 103 } 104 105 my $message = ${$proxy->message_list}[0]; 106 107 my $ext; 108 if ($testtype == FALLBACK_FROM_TLS_1_3) { 109 #The default ciphersuite we use for TLSv1.2 without any SCSV 110 my @ciphersuites = (TLSProxy::Message::CIPHER_RSA_WITH_AES_128_CBC_SHA); 111 $message->ciphersuite_len(2 * scalar @ciphersuites); 112 $message->ciphersuites(\@ciphersuites); 113 } else { 114 if ($testtype == DOWNGRADE_TO_TLS_1_2) { 115 $ext = pack "C3", 116 0x02, # Length 117 0x03, 0x03; #TLSv1.2 118 } else { 119 $ext = pack "C3", 120 0x02, # Length 121 0x03, 0x02; #TLSv1.1 122 } 123 124 $message->set_extension(TLSProxy::Message::EXT_SUPPORTED_VERSIONS, $ext); 125 } 126 127 $message->repack(); 128} 129 130