#! /usr/bin/env perl

# 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

use strict;

use feature 'state';

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

use OpenSSL::Test::Utils;

use TLSProxy::Proxy;

my $test_name = "test_sslcbcpadding";

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 TLSv1.2 enabled"

    if disabled("tls1_2");

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

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

    \&add_maximal_padding_filter,

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

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

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

);

# TODO: We could test all 256 values, but then the log file gets too large for

# CI. See https://github.com/openssl/openssl/issues/1440.

my @test_offsets = (0, 128, 254, 255);

# Test that maximally-padded records are accepted.

my $bad_padding_offset = -1;

$proxy->serverflags("-tls1_2");

$proxy->serverconnects(1 + scalar(@test_offsets));

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

plan tests => 1 + scalar(@test_offsets);

ok(TLSProxy::Message->success(), "Maximally-padded record test");

# Test that invalid padding is rejected.

my $fatal_alert;    # set by add_maximal_padding_filter on client's fatal alert

foreach my $offset (@test_offsets) {

    $bad_padding_offset = $offset;

    $fatal_alert = 0;

    $proxy->clearClient();

    $proxy->clientstart();

    ok($fatal_alert, "Invalid padding byte $bad_padding_offset");

}

sub add_maximal_padding_filter

{

    my $proxy = shift;

    my $messages = $proxy->message_list;

    state $sent_corrupted_payload;

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

        # Disable Encrypt-then-MAC.

        foreach my $message (@{$messages}) {

            if ($message->mt != TLSProxy::Message::MT_CLIENT_HELLO) {

                next;

            }

            $message->delete_extension(TLSProxy::Message::EXT_ENCRYPT_THEN_MAC);

            $message->process_extensions();

            $message->repack();

        }

        $sent_corrupted_payload = 0;

        return;

    }

    my $last_message = @{$messages}[-1];

    if (defined($last_message)

        && $last_message->server

        && $last_message->mt == TLSProxy::Message::MT_FINISHED

        && !@{$last_message->records}[0]->{sent}) {

        # Insert a maximally-padded record. Assume a block size of 16 (AES) and

        # a MAC length of 20 (SHA-1).

        my $block_size = 16;

        my $mac_len = 20;

        # Size the plaintext so that 256 is a valid padding.

        my $plaintext_len = $block_size - ($mac_len % $block_size);

        my $plaintext = "A" x $plaintext_len;

        my $data = "B" x $block_size; # Explicit IV.

        $data .= $plaintext;

        $data .= TLSProxy::Proxy::fill_known_data($mac_len); # MAC.

        # Add padding.

        for (my $i = 0; $i < 256; $i++) {

            if ($i == $bad_padding_offset) {

                $sent_corrupted_payload = 1;

                $data .= "\xfe";

            } else {

                $data .= "\xff";

            }

        }

        my $record = TLSProxy::Record->new(

            $proxy->flight,

            TLSProxy::Record::RT_APPLICATION_DATA,

            TLSProxy::Record::VERS_TLS_1_2,

            length($data),

            0,

            length($data),

            $plaintext_len,

            $data,

            $plaintext,

        );

        # Send the record immediately after the server Finished.

        push @{$proxy->record_list}, $record;

    } elsif ($sent_corrupted_payload) {

        # Check for bad_record_mac from client

        my $last_record = @{$proxy->record_list}[-1];

        $fatal_alert = 1 if $last_record->is_fatal_alert(0) == 20;

    }

}