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