1#! /usr/bin/env perl
2# Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
3#
4# Licensed under the OpenSSL license (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 feature 'state';
11
12use OpenSSL::Test qw/:DEFAULT cmdstr srctop_file bldtop_dir/;
13use OpenSSL::Test::Utils;
14use TLSProxy::Proxy;
15
16my $test_name = "test_sslcbcpadding";
17setup($test_name);
18
19plan skip_all => "TLSProxy isn't usable on $^O"
20    if $^O =~ /^(VMS)$/;
21
22plan skip_all => "$test_name needs the dynamic engine feature enabled"
23    if disabled("engine") || disabled("dynamic-engine");
24
25plan skip_all => "$test_name needs the sock feature enabled"
26    if disabled("sock");
27
28plan skip_all => "$test_name needs TLSv1.2 enabled"
29    if disabled("tls1_2");
30
31$ENV{OPENSSL_ia32cap} = '~0x200000200000000';
32my $proxy = TLSProxy::Proxy->new(
33    \&add_maximal_padding_filter,
34    cmdstr(app(["openssl"]), display => 1),
35    srctop_file("apps", "server.pem"),
36    (!$ENV{HARNESS_ACTIVE} || $ENV{HARNESS_VERBOSE})
37);
38
39# TODO: We could test all 256 values, but then the log file gets too large for
40# CI. See https://github.com/openssl/openssl/issues/1440.
41my @test_offsets = (0, 128, 254, 255);
42
43# Test that maximally-padded records are accepted.
44my $bad_padding_offset = -1;
45$proxy->serverflags("-tls1_2");
46$proxy->serverconnects(1 + scalar(@test_offsets));
47$proxy->start() or plan skip_all => "Unable to start up Proxy for tests";
48plan tests => 1 + scalar(@test_offsets);
49ok(TLSProxy::Message->success(), "Maximally-padded record test");
50
51# Test that invalid padding is rejected.
52my $fatal_alert;    # set by add_maximal_padding_filter on client's fatal alert
53
54foreach my $offset (@test_offsets) {
55    $bad_padding_offset = $offset;
56    $fatal_alert = 0;
57    $proxy->clearClient();
58    $proxy->clientstart();
59    ok($fatal_alert, "Invalid padding byte $bad_padding_offset");
60}
61
62sub add_maximal_padding_filter
63{
64    my $proxy = shift;
65    my $messages = $proxy->message_list;
66    state $sent_corrupted_payload;
67
68    if ($proxy->flight == 0) {
69        # Disable Encrypt-then-MAC.
70        foreach my $message (@{$messages}) {
71            if ($message->mt != TLSProxy::Message::MT_CLIENT_HELLO) {
72                next;
73            }
74
75            $message->delete_extension(TLSProxy::Message::EXT_ENCRYPT_THEN_MAC);
76            $message->process_extensions();
77            $message->repack();
78        }
79        $sent_corrupted_payload = 0;
80        return;
81    }
82
83    my $last_message = @{$messages}[-1];
84    if (defined($last_message)
85        && $last_message->server
86        && $last_message->mt == TLSProxy::Message::MT_FINISHED
87        && !@{$last_message->records}[0]->{sent}) {
88
89        # Insert a maximally-padded record. Assume a block size of 16 (AES) and
90        # a MAC length of 20 (SHA-1).
91        my $block_size = 16;
92        my $mac_len = 20;
93
94        # Size the plaintext so that 256 is a valid padding.
95        my $plaintext_len = $block_size - ($mac_len % $block_size);
96        my $plaintext = "A" x $plaintext_len;
97
98        my $data = "B" x $block_size; # Explicit IV.
99        $data .= $plaintext;
100        $data .= TLSProxy::Proxy::fill_known_data($mac_len); # MAC.
101
102        # Add padding.
103        for (my $i = 0; $i < 256; $i++) {
104            if ($i == $bad_padding_offset) {
105                $sent_corrupted_payload = 1;
106                $data .= "\xfe";
107            } else {
108                $data .= "\xff";
109            }
110        }
111
112        my $record = TLSProxy::Record->new(
113            $proxy->flight,
114            TLSProxy::Record::RT_APPLICATION_DATA,
115            TLSProxy::Record::VERS_TLS_1_2,
116            length($data),
117            0,
118            length($data),
119            $plaintext_len,
120            $data,
121            $plaintext,
122        );
123
124        # Send the record immediately after the server Finished.
125        push @{$proxy->record_list}, $record;
126    } elsif ($sent_corrupted_payload) {
127        # Check for bad_record_mac from client
128        my $last_record = @{$proxy->record_list}[-1];
129        $fatal_alert = 1 if $last_record->is_fatal_alert(0) == 20;
130    }
131}
132