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 31my $proxy = TLSProxy::Proxy->new( 32 undef, 33 cmdstr(app(["openssl"]), display => 1), 34 srctop_file("apps", "server.pem"), 35 (!$ENV{HARNESS_ACTIVE} || $ENV{HARNESS_VERBOSE}) 36); 37 38use constant { 39 DOWNGRADE_TO_TLS_1_2 => 0, 40 DOWNGRADE_TO_TLS_1_1 => 1, 41 FALLBACK_FROM_TLS_1_3 => 2, 42}; 43 44#Test 1: Downgrade from TLSv1.3 to TLSv1.2 45$proxy->filter(\&downgrade_filter); 46my $testtype = DOWNGRADE_TO_TLS_1_2; 47$proxy->start() or plan skip_all => "Unable to start up Proxy for tests"; 48plan tests => 6; 49ok(TLSProxy::Message->fail(), "Downgrade TLSv1.3 to TLSv1.2"); 50 51#Test 2: Downgrade from TLSv1.3 to TLSv1.1 52$proxy->clear(); 53$testtype = DOWNGRADE_TO_TLS_1_1; 54$proxy->start(); 55ok(TLSProxy::Message->fail(), "Downgrade TLSv1.3 to TLSv1.1"); 56 57#Test 3: Downgrade from TLSv1.2 to TLSv1.1 58$proxy->clear(); 59$proxy->clientflags("-no_tls1_3"); 60$proxy->serverflags("-no_tls1_3"); 61$proxy->start(); 62ok(TLSProxy::Message->fail(), "Downgrade TLSv1.2 to TLSv1.1"); 63 64#Test 4: Client falls back from TLSv1.3 (server does not support the fallback 65# SCSV) 66$proxy->clear(); 67$testtype = FALLBACK_FROM_TLS_1_3; 68$proxy->clientflags("-fallback_scsv -no_tls1_3"); 69$proxy->start(); 70my $alert = TLSProxy::Message->alert(); 71ok(TLSProxy::Message->fail() 72 && !$alert->server() 73 && $alert->description() == TLSProxy::Message::AL_DESC_ILLEGAL_PARAMETER, 74 "Fallback from TLSv1.3"); 75 76SKIP: { 77 skip "TLSv1.1 disabled", 2 if disabled("tls1_1"); 78 #Test 5: A client side protocol "hole" should not be detected as a downgrade 79 $proxy->clear(); 80 $proxy->filter(undef); 81 $proxy->clientflags("-no_tls1_2"); 82 $proxy->ciphers("AES128-SHA:\@SECLEVEL=0"); 83 $proxy->start(); 84 ok(TLSProxy::Message->success(), "TLSv1.2 client-side protocol hole"); 85 86 #Test 6: A server side protocol "hole" should not be detected as a downgrade 87 $proxy->clear(); 88 $proxy->filter(undef); 89 $proxy->serverflags("-no_tls1_2"); 90 $proxy->start(); 91 ok(TLSProxy::Message->success(), "TLSv1.2 server-side protocol hole"); 92} 93 94sub downgrade_filter 95{ 96 my $proxy = shift; 97 98 # We're only interested in the initial ClientHello 99 if ($proxy->flight != 0) { 100 return; 101 } 102 103 my $message = ${$proxy->message_list}[0]; 104 105 my $ext; 106 if ($testtype == FALLBACK_FROM_TLS_1_3) { 107 #The default ciphersuite we use for TLSv1.2 without any SCSV 108 my @ciphersuites = (TLSProxy::Message::CIPHER_RSA_WITH_AES_128_CBC_SHA); 109 $message->ciphersuite_len(2 * scalar @ciphersuites); 110 $message->ciphersuites(\@ciphersuites); 111 } else { 112 if ($testtype == DOWNGRADE_TO_TLS_1_2) { 113 $ext = pack "C3", 114 0x02, # Length 115 0x03, 0x03; #TLSv1.2 116 } else { 117 $ext = pack "C3", 118 0x02, # Length 119 0x03, 0x02; #TLSv1.1 120 } 121 122 $message->set_extension(TLSProxy::Message::EXT_SUPPORTED_VERSIONS, $ext); 123 } 124 125 $message->repack(); 126} 127 128