openssl/util/TLSProxy/Message.pm
Matt Caswell a1accbb1d7 Extend TLSProxy capabilities
Add ServerHello parsing to TLSProxy.
Also add some (very) limited ServerKeyExchange parsing.
Add the capability to set client and server cipher lists
Fix a bug with fragment lengths

Reviewed-by: Richard Levitte <levitte@openssl.org>
2015-08-11 20:27:46 +01:00

457 lines
14 KiB
Perl

# Written by Matt Caswell for the OpenSSL project.
# ====================================================================
# Copyright (c) 1998-2015 The OpenSSL Project. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
#
# 3. All advertising materials mentioning features or use of this
# software must display the following acknowledgment:
# "This product includes software developed by the OpenSSL Project
# for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
#
# 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
# endorse or promote products derived from this software without
# prior written permission. For written permission, please contact
# openssl-core@openssl.org.
#
# 5. Products derived from this software may not be called "OpenSSL"
# nor may "OpenSSL" appear in their names without prior written
# permission of the OpenSSL Project.
#
# 6. Redistributions of any form whatsoever must retain the following
# acknowledgment:
# "This product includes software developed by the OpenSSL Project
# for use in the OpenSSL Toolkit (http://www.openssl.org/)"
#
# THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
# EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
# ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
# OF THE POSSIBILITY OF SUCH DAMAGE.
# ====================================================================
#
# This product includes cryptographic software written by Eric Young
# (eay@cryptsoft.com). This product includes software written by Tim
# Hudson (tjh@cryptsoft.com).
use strict;
package TLSProxy::Message;
use constant TLS_MESSAGE_HEADER_LENGTH => 4;
#Message types
use constant {
MT_HELLO_REQUEST => 0,
MT_CLIENT_HELLO => 1,
MT_SERVER_HELLO => 2,
MT_NEW_SESSION_TICKET => 4,
MT_CERTIFICATE => 11,
MT_SERVER_KEY_EXCHANGE => 12,
MT_CERTIFICATE_REQUEST => 13,
MT_SERVER_HELLO_DONE => 14,
MT_CERTIFICATE_VERIFY => 15,
MT_CLIENT_KEY_EXCHANGE => 16,
MT_FINISHED => 20,
MT_CERTIFICATE_STATUS => 22,
MT_NEXT_PROTO => 67
};
my %message_type = (
MT_HELLO_REQUEST, "HelloRequest",
MT_CLIENT_HELLO, "ClientHello",
MT_SERVER_HELLO, "ServerHello",
MT_NEW_SESSION_TICKET, "NewSessionTicket",
MT_CERTIFICATE, "Certificate",
MT_SERVER_KEY_EXCHANGE, "ServerKeyExchange",
MT_CERTIFICATE_REQUEST, "CertificateRequest",
MT_SERVER_HELLO_DONE, "ServerHelloDone",
MT_CERTIFICATE_VERIFY, "CertificateVerify",
MT_CLIENT_KEY_EXCHANGE, "ClientKeyExchange",
MT_FINISHED, "Finished",
MT_CERTIFICATE_STATUS, "CertificateStatus",
MT_NEXT_PROTO, "NextProto"
);
my $payload = "";
my $messlen = -1;
my $mt;
my $startoffset = -1;
my $server = 0;
my $success = 0;
my $end = 0;
my @message_rec_list = ();
my @message_frag_lens = ();
my $ciphersuite = 0;
sub clear
{
$payload = "";
$messlen = -1;
$startoffset = -1;
$server = 0;
$success = 0;
$end = 0;
@message_rec_list = ();
@message_frag_lens = ();
}
#Class method to extract messages from a record
sub get_messages
{
my $class = shift;
my $serverin = shift;
my $record = shift;
my @messages = ();
my $message;
@message_frag_lens = ();
if ($serverin != $server && length($payload) != 0) {
die "Changed peer, but we still have fragment data\n";
}
$server = $serverin;
if ($record->content_type == TLSProxy::Record::RT_CCS) {
if ($payload ne "") {
#We can't handle this yet
die "CCS received before message data complete\n";
}
if ($server) {
TLSProxy::Record->server_ccs_seen(1);
} else {
TLSProxy::Record->client_ccs_seen(1);
}
} elsif ($record->content_type == TLSProxy::Record::RT_HANDSHAKE) {
if ($record->len == 0 || $record->len_real == 0) {
print " Message truncated\n";
} else {
my $recoffset = 0;
if (length $payload > 0) {
#We are continuing processing a message started in a previous
#record. Add this record to the list associated with this
#message
push @message_rec_list, $record;
if ($messlen <= length($payload)) {
#Shouldn't happen
die "Internal error: invalid messlen: ".$messlen
." payload length:".length($payload)."\n";
}
if (length($payload) + $record->decrypt_len >= $messlen) {
#We can complete the message with this record
$recoffset = $messlen - length($payload);
$payload .= substr($record->decrypt_data, 0, $recoffset);
push @message_frag_lens, $recoffset;
$message = create_message($server, $mt, $payload,
$startoffset);
push @messages, $message;
#Check if we have finished the handshake
if ($mt == MT_FINISHED && $server) {
$success = 1;
$end = 1;
}
$payload = "";
} else {
#This is just part of the total message
$payload .= $record->decrypt_data;
$recoffset = $record->decrypt_len;
push @message_frag_lens, $record->decrypt_len;
}
print " Partial message data read: ".$recoffset." bytes\n";
}
while ($record->decrypt_len > $recoffset) {
#We are at the start of a new message
if ($record->decrypt_len - $recoffset < 4) {
#Whilst technically probably valid we can't cope with this
die "End of record in the middle of a message header\n";
}
@message_rec_list = ($record);
my $lenhi;
my $lenlo;
($mt, $lenhi, $lenlo) = unpack('CnC',
substr($record->decrypt_data,
$recoffset));
$messlen = ($lenhi << 8) | $lenlo;
print " Message type: $message_type{$mt}\n";
print " Message Length: $messlen\n";
$startoffset = $recoffset;
$recoffset += 4;
$payload = "";
if ($recoffset < $record->decrypt_len) {
#Some payload data is present in this record
if ($record->decrypt_len - $recoffset >= $messlen) {
#We can complete the message with this record
$payload .= substr($record->decrypt_data, $recoffset,
$messlen);
$recoffset += $messlen;
push @message_frag_lens, $messlen;
$message = create_message($server, $mt, $payload,
$startoffset);
push @messages, $message;
#Check if we have finished the handshake
if ($mt == MT_FINISHED && $server) {
$success = 1;
$end = 1;
}
$payload = "";
} else {
#This is just part of the total message
$payload .= substr($record->decrypt_data, $recoffset,
$record->decrypt_len - $recoffset);
$recoffset = $record->decrypt_len;
push @message_frag_lens, $recoffset;
}
}
}
}
} elsif ($record->content_type == TLSProxy::Record::RT_APPLICATION_DATA) {
print " [ENCRYPTED APPLICATION DATA]\n";
print " [".$record->decrypt_data."]\n";
} elsif ($record->content_type == TLSProxy::Record::RT_ALERT) {
#For now assume all alerts are fatal
$end = 1;
}
return @messages;
}
#Function to work out which sub-class we need to create and then
#construct it
sub create_message
{
my ($server, $mt, $data, $startoffset) = @_;
my $message;
#We only support ClientHello in this version...needs to be extended for
#others
if ($mt == MT_CLIENT_HELLO) {
$message = TLSProxy::ClientHello->new(
$server,
$data,
[@message_rec_list],
$startoffset,
[@message_frag_lens]
);
$message->parse();
} elsif ($mt == MT_SERVER_HELLO) {
$message = TLSProxy::ServerHello->new(
$server,
$data,
[@message_rec_list],
$startoffset,
[@message_frag_lens]
);
$message->parse();
} elsif ($mt == MT_SERVER_KEY_EXCHANGE) {
$message = TLSProxy::ServerKeyExchange->new(
$server,
$data,
[@message_rec_list],
$startoffset,
[@message_frag_lens]
);
$message->parse();
} else {
#Unknown message type
$message = TLSProxy::Message->new(
$server,
$mt,
$data,
[@message_rec_list],
$startoffset,
[@message_frag_lens]
);
}
return $message;
}
sub end
{
my $class = shift;
return $end;
}
sub success
{
my $class = shift;
return $success;
}
sub fail
{
my $class = shift;
return !$success && $end;
}
sub new
{
my $class = shift;
my ($server,
$mt,
$data,
$records,
$startoffset,
$message_frag_lens) = @_;
my $self = {
server => $server,
data => $data,
records => $records,
mt => $mt,
startoffset => $startoffset,
message_frag_lens => $message_frag_lens
};
return bless $self, $class;
}
sub ciphersuite
{
my $class = shift;
if (@_) {
$ciphersuite = shift;
}
return $ciphersuite;
}
#Update all the underlying records with the modified data from this message
#Note: Does not currently support re-encrypting
sub repack
{
my $self = shift;
my $msgdata;
my $numrecs = $#{$self->records};
$self->set_message_contents();
my $lenhi;
my $lenlo;
$lenlo = length($self->data) & 0xff;
$lenhi = length($self->data) >> 8;
my $msgdata = pack('CnC', $self->mt, $lenhi, $lenlo).$self->data;
if ($numrecs == 0) {
#The message is fully contained within one record
my ($rec) = @{$self->records};
my $recdata = $rec->decrypt_data;
if (length($msgdata) != ${$self->message_frag_lens}[0]
+ TLS_MESSAGE_HEADER_LENGTH) {
#Message length has changed! Better adjust the record length
my $diff = length($msgdata) - ${$self->message_frag_lens}[0]
- TLS_MESSAGE_HEADER_LENGTH;
$rec->len($rec->len + $diff);
}
$rec->data(substr($recdata, 0, $self->startoffset)
.($msgdata)
.substr($recdata, ${$self->message_frag_lens}[0]
+ TLS_MESSAGE_HEADER_LENGTH));
#Update the fragment len in case we changed it above
${$self->message_frag_lens}[0] = length($msgdata)
- TLS_MESSAGE_HEADER_LENGTH;
return;
}
#Note we don't currently support changing a fragmented message length
my $recctr = 0;
my $datadone = 0;
foreach my $rec (@{$self->records}) {
my $recdata = $rec->decrypt_data;
if ($recctr == 0) {
#This is the first record
my $remainlen = length($recdata) - $self->startoffset;
$rec->data(substr($recdata, 0, $self->startoffset)
.substr(($msgdata), 0, $remainlen));
$datadone += $remainlen;
} elsif ($recctr + 1 == $numrecs) {
#This is the last record
$rec->data(substr($msgdata, $datadone));
} else {
#This is a middle record
$rec->data(substr($msgdata, $datadone, length($rec->data)));
$datadone += length($rec->data);
}
$recctr++;
}
}
#To be overridden by sub-classes
sub set_message_contents
{
}
#Read only accessors
sub server
{
my $self = shift;
return $self->{server};
}
#Read/write accessors
sub mt
{
my $self = shift;
if (@_) {
$self->{mt} = shift;
}
return $self->{mt};
}
sub data
{
my $self = shift;
if (@_) {
$self->{data} = shift;
}
return $self->{data};
}
sub records
{
my $self = shift;
if (@_) {
$self->{records} = shift;
}
return $self->{records};
}
sub startoffset
{
my $self = shift;
if (@_) {
$self->{startoffset} = shift;
}
return $self->{startoffset};
}
sub message_frag_lens
{
my $self = shift;
if (@_) {
$self->{message_frag_lens} = shift;
}
return $self->{message_frag_lens};
}
1;