1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
|
# 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 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_DRAFT => 0x7f1c,
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) {
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
|