openssl/util/perl/TLSProxy/Record.pm

402 lines
9.3 KiB
Perl

# Copyright 2016-2019 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 TLSProxy::Proxy;
package TLSProxy::Record;
my $server_encrypting = 0;
my $client_encrypting = 0;
my $etm = 0;
use constant TLS_RECORD_HEADER_LENGTH => 5;
#Record types
use constant {
RT_APPLICATION_DATA => 23,
RT_HANDSHAKE => 22,
RT_ALERT => 21,
RT_CCS => 20,
RT_UNKNOWN => 100
};
my %record_type = (
RT_APPLICATION_DATA, "APPLICATION DATA",
RT_HANDSHAKE, "HANDSHAKE",
RT_ALERT, "ALERT",
RT_CCS, "CCS",
RT_UNKNOWN, "UNKNOWN"
);
use constant {
VERS_TLS_1_4 => 0x0305,
VERS_TLS_1_3 => 0x0304,
VERS_TLS_1_2 => 0x0303,
VERS_TLS_1_1 => 0x0302,
VERS_TLS_1_0 => 0x0301,
VERS_SSL_3_0 => 0x0300,
VERS_SSL_LT_3_0 => 0x02ff
};
my %tls_version = (
VERS_TLS_1_3, "TLS1.3",
VERS_TLS_1_2, "TLS1.2",
VERS_TLS_1_1, "TLS1.1",
VERS_TLS_1_0, "TLS1.0",
VERS_SSL_3_0, "SSL3",
VERS_SSL_LT_3_0, "SSL<3"
);
#Class method to extract records from a packet of data
sub get_records
{
my $class = shift;
my $server = shift;
my $flight = shift;
my $packet = shift;
my $partial = "";
my @record_list = ();
my @message_list = ();
my $recnum = 1;
while (length ($packet) > 0) {
print " Record $recnum ", $server ? "(server -> client)\n"
: "(client -> server)\n";
#Get the record header (unpack can't fail if $packet is too short)
my ($content_type, $version, $len) = unpack('Cnn', $packet);
if (length($packet) < TLS_RECORD_HEADER_LENGTH + ($len // 0)) {
print "Partial data : ".length($packet)." bytes\n";
$partial = $packet;
last;
}
my $data = substr($packet, TLS_RECORD_HEADER_LENGTH, $len);
print " Content type: ".$record_type{$content_type}."\n";
print " Version: $tls_version{$version}\n";
print " Length: $len\n";
my $record = TLSProxy::Record->new(
$flight,
$content_type,
$version,
$len,
0,
$len, # len_real
$len, # decrypt_len
$data, # data
$data # decrypt_data
);
if ($content_type != RT_CCS
&& (!TLSProxy::Proxy->is_tls13()
|| $content_type != RT_ALERT)) {
if (($server && $server_encrypting)
|| (!$server && $client_encrypting)) {
if (!TLSProxy::Proxy->is_tls13() && $etm) {
$record->decryptETM();
} else {
$record->decrypt();
}
$record->encrypted(1);
if (TLSProxy::Proxy->is_tls13()) {
print " Inner content type: "
.$record_type{$record->content_type()}."\n";
}
}
}
push @record_list, $record;
#Now figure out what messages are contained within this record
my @messages = TLSProxy::Message->get_messages($server, $record);
push @message_list, @messages;
$packet = substr($packet, TLS_RECORD_HEADER_LENGTH + $len);
$recnum++;
}
return (\@record_list, \@message_list, $partial);
}
sub clear
{
$server_encrypting = 0;
$client_encrypting = 0;
}
#Class level accessors
sub server_encrypting
{
my $class = shift;
if (@_) {
$server_encrypting = shift;
}
return $server_encrypting;
}
sub client_encrypting
{
my $class = shift;
if (@_) {
$client_encrypting= shift;
}
return $client_encrypting;
}
#Enable/Disable Encrypt-then-MAC
sub etm
{
my $class = shift;
if (@_) {
$etm = shift;
}
return $etm;
}
sub new
{
my $class = shift;
my ($flight,
$content_type,
$version,
$len,
$sslv2,
$len_real,
$decrypt_len,
$data,
$decrypt_data) = @_;
my $self = {
flight => $flight,
content_type => $content_type,
version => $version,
len => $len,
sslv2 => $sslv2,
len_real => $len_real,
decrypt_len => $decrypt_len,
data => $data,
decrypt_data => $decrypt_data,
orig_decrypt_data => $decrypt_data,
sent => 0,
encrypted => 0,
outer_content_type => RT_APPLICATION_DATA
};
return bless $self, $class;
}
#Decrypt using encrypt-then-MAC
sub decryptETM
{
my ($self) = shift;
my $data = $self->data;
if($self->version >= VERS_TLS_1_1()) {
#TLS1.1+ has an explicit IV. Throw it away
$data = substr($data, 16);
}
#Throw away the MAC (assumes MAC is 20 bytes for now. FIXME)
$data = substr($data, 0, length($data) - 20);
#Find out what the padding byte is
my $padval = unpack("C", substr($data, length($data) - 1));
#Throw away the padding
$data = substr($data, 0, length($data) - ($padval + 1));
$self->decrypt_data($data);
$self->decrypt_len(length($data));
return $data;
}
#Standard decrypt
sub decrypt()
{
my ($self) = shift;
my $mactaglen = 20;
my $data = $self->data;
#Throw away any IVs
if (TLSProxy::Proxy->is_tls13()) {
#A TLS1.3 client, when processing the server's initial flight, could
#respond with either an encrypted or an unencrypted alert.
if ($self->content_type() == RT_ALERT) {
#TODO(TLS1.3): Eventually it is sufficient just to check the record
#content type. If an alert is encrypted it will have a record
#content type of application data. However we haven't done the
#record layer changes yet, so it's a bit more complicated. For now
#we will additionally check if the data length is 2 (1 byte for
#alert level, 1 byte for alert description). If it is, then this is
#an unencrypted alert, so don't try to decrypt
return $data if (length($data) == 2);
}
$mactaglen = 16;
} elsif ($self->version >= VERS_TLS_1_1()) {
#16 bytes for a standard IV
$data = substr($data, 16);
#Find out what the padding byte is
my $padval = unpack("C", substr($data, length($data) - 1));
#Throw away the padding
$data = substr($data, 0, length($data) - ($padval + 1));
}
#Throw away the MAC or TAG
$data = substr($data, 0, length($data) - $mactaglen);
if (TLSProxy::Proxy->is_tls13()) {
#Get the content type
my $content_type = unpack("C", substr($data, length($data) - 1));
$self->content_type($content_type);
$data = substr($data, 0, length($data) - 1);
}
$self->decrypt_data($data);
$self->decrypt_len(length($data));
return $data;
}
#Reconstruct the on-the-wire record representation
sub reconstruct_record
{
my $self = shift;
my $server = shift;
my $data;
#We only replay the records in the same direction
if ($self->{sent} || ($self->flight & 1) != $server) {
return "";
}
$self->{sent} = 1;
if ($self->sslv2) {
$data = pack('n', $self->len | 0x8000);
} else {
if (TLSProxy::Proxy->is_tls13() && $self->encrypted) {
$data = pack('Cnn', $self->outer_content_type, $self->version,
$self->len);
} else {
$data = pack('Cnn', $self->content_type, $self->version,
$self->len);
}
}
$data .= $self->data;
return $data;
}
#Read only accessors
sub flight
{
my $self = shift;
return $self->{flight};
}
sub sslv2
{
my $self = shift;
return $self->{sslv2};
}
sub len_real
{
my $self = shift;
return $self->{len_real};
}
sub orig_decrypt_data
{
my $self = shift;
return $self->{orig_decrypt_data};
}
#Read/write accessors
sub decrypt_len
{
my $self = shift;
if (@_) {
$self->{decrypt_len} = shift;
}
return $self->{decrypt_len};
}
sub data
{
my $self = shift;
if (@_) {
$self->{data} = shift;
}
return $self->{data};
}
sub decrypt_data
{
my $self = shift;
if (@_) {
$self->{decrypt_data} = shift;
}
return $self->{decrypt_data};
}
sub len
{
my $self = shift;
if (@_) {
$self->{len} = shift;
}
return $self->{len};
}
sub version
{
my $self = shift;
if (@_) {
$self->{version} = shift;
}
return $self->{version};
}
sub content_type
{
my $self = shift;
if (@_) {
$self->{content_type} = shift;
}
return $self->{content_type};
}
sub encrypted
{
my $self = shift;
if (@_) {
$self->{encrypted} = shift;
}
return $self->{encrypted};
}
sub outer_content_type
{
my $self = shift;
if (@_) {
$self->{outer_content_type} = shift;
}
return $self->{outer_content_type};
}
sub is_fatal_alert
{
my $self = shift;
my $server = shift;
if (($self->{flight} & 1) == $server
&& $self->{content_type} == TLSProxy::Record::RT_ALERT) {
my ($level, $alert) = unpack('CC', $self->decrypt_data);
return $alert if ($level == 2);
}
return 0;
}
1;