util/TLSProxy/Message.pm

   1 # Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
   2 #
   3 # Licensed under the OpenSSL license (the "License").  You may not use
   4 # this file except in compliance with the License.  You can obtain a copy
   5 # in the file LICENSE in the source distribution or at
   6 # https://www.openssl.org/source/license.html
   7
   8 use strict;
   9
  10 package TLSProxy::Message;
  11
  12 use constant TLS_MESSAGE_HEADER_LENGTH => 4;
  13
  14 #Message types
  15 use constant {
  16     MT_HELLO_REQUEST => 0,
  17     MT_CLIENT_HELLO => 1,
  18     MT_SERVER_HELLO => 2,
  19     MT_NEW_SESSION_TICKET => 4,
  20     MT_ENCRYPTED_EXTENSIONS => 8,
  21     MT_CERTIFICATE => 11,
  22     MT_SERVER_KEY_EXCHANGE => 12,
  23     MT_CERTIFICATE_REQUEST => 13,
  24     MT_SERVER_HELLO_DONE => 14,
  25     MT_CERTIFICATE_VERIFY => 15,
  26     MT_CLIENT_KEY_EXCHANGE => 16,
  27     MT_FINISHED => 20,
  28     MT_CERTIFICATE_STATUS => 22,
  29     MT_NEXT_PROTO => 67
  30 };
  31
  32 #Alert levels
  33 use constant {
  34     AL_LEVEL_WARN => 1,
  35     AL_LEVEL_FATAL => 2
  36 };
  37
  38 #Alert descriptions
  39 use constant {
  40     AL_DESC_CLOSE_NOTIFY => 0,
  41     AL_DESC_UNEXPECTED_MESSAGE => 10,
  42     AL_DESC_NO_RENEGOTIATION => 100
  43 };
  44
  45 my %message_type = (
  46     MT_HELLO_REQUEST, "HelloRequest",
  47     MT_CLIENT_HELLO, "ClientHello",
  48     MT_SERVER_HELLO, "ServerHello",
  49     MT_NEW_SESSION_TICKET, "NewSessionTicket",
  50     MT_ENCRYPTED_EXTENSIONS, "EncryptedExtensions",
  51     MT_CERTIFICATE, "Certificate",
  52     MT_SERVER_KEY_EXCHANGE, "ServerKeyExchange",
  53     MT_CERTIFICATE_REQUEST, "CertificateRequest",
  54     MT_SERVER_HELLO_DONE, "ServerHelloDone",
  55     MT_CERTIFICATE_VERIFY, "CertificateVerify",
  56     MT_CLIENT_KEY_EXCHANGE, "ClientKeyExchange",
  57     MT_FINISHED, "Finished",
  58     MT_CERTIFICATE_STATUS, "CertificateStatus",
  59     MT_NEXT_PROTO, "NextProto"
  60 );
  61
  62 use constant {
  63     EXT_STATUS_REQUEST => 5,
  64     EXT_SUPPORTED_GROUPS => 10,
  65     EXT_ENCRYPT_THEN_MAC => 22,
  66     EXT_EXTENDED_MASTER_SECRET => 23,
  67     EXT_SESSION_TICKET => 35,
  68     EXT_SUPPORTED_VERSIONS => 43,
  69     EXT_KEY_SHARE => 40,
  70     # This extension is an unofficial extension only ever written by OpenSSL
  71     # (i.e. not read), and even then only when enabled. We use it to test
  72     # handling of duplicate extensions.
  73     EXT_DUPLICATE_EXTENSION => 0xfde8
  74 };
  75
  76 my $payload = "";
  77 my $messlen = -1;
  78 my $mt;
  79 my $startoffset = -1;
  80 my $server = 0;
  81 my $success = 0;
  82 my $end = 0;
  83 my @message_rec_list = ();
  84 my @message_frag_lens = ();
  85 my $ciphersuite = 0;
  86
  87 sub clear
  88 {
  89     $payload = "";
  90     $messlen = -1;
  91     $startoffset = -1;
  92     $server = 0;
  93     $success = 0;
  94     $end = 0;
  95     @message_rec_list = ();
  96     @message_frag_lens = ();
  97 }
  98
  99 #Class method to extract messages from a record
 100 sub get_messages
 101 {
 102     my $class = shift;
 103     my $serverin = shift;
 104     my $record = shift;
 105     my @messages = ();
 106     my $message;
 107
 108     @message_frag_lens = ();
 109
 110     if ($serverin != $server && length($payload) != 0) {
 111         die "Changed peer, but we still have fragment data\n";
 112     }
 113     $server = $serverin;
 114
 115     if ($record->content_type == TLSProxy::Record::RT_CCS) {
 116         if ($payload ne "") {
 117             #We can't handle this yet
 118             die "CCS received before message data complete\n";
 119         }
 120         if ($server) {
 121             TLSProxy::Record->server_encrypting(1);
 122         } else {
 123             TLSProxy::Record->client_encrypting(1);
 124         }
 125     } elsif ($record->content_type == TLSProxy::Record::RT_HANDSHAKE) {
 126         if ($record->len == 0 || $record->len_real == 0) {
 127             print "  Message truncated\n";
 128         } else {
 129             my $recoffset = 0;
 130
 131             if (length $payload > 0) {
 132                 #We are continuing processing a message started in a previous
 133                 #record. Add this record to the list associated with this
 134                 #message
 135                 push @message_rec_list, $record;
 136
 137                 if ($messlen <= length($payload)) {
 138                     #Shouldn't happen
 139                     die "Internal error: invalid messlen: ".$messlen
 140                         ." payload length:".length($payload)."\n";
 141                 }
 142                 if (length($payload) + $record->decrypt_len >= $messlen) {
 143                     #We can complete the message with this record
 144                     $recoffset = $messlen - length($payload);
 145                     $payload .= substr($record->decrypt_data, 0, $recoffset);
 146                     push @message_frag_lens, $recoffset;
 147                     $message = create_message($server, $mt, $payload,
 148                                               $startoffset);
 149                     push @messages, $message;
 150
 151                     $payload = "";
 152                 } else {
 153                     #This is just part of the total message
 154                     $payload .= $record->decrypt_data;
 155                     $recoffset = $record->decrypt_len;
 156                     push @message_frag_lens, $record->decrypt_len;
 157                 }
 158                 print "  Partial message data read: ".$recoffset." bytes\n";
 159             }
 160
 161             while ($record->decrypt_len > $recoffset) {
 162                 #We are at the start of a new message
 163                 if ($record->decrypt_len - $recoffset < 4) {
 164                     #Whilst technically probably valid we can't cope with this
 165                     die "End of record in the middle of a message header\n";
 166                 }
 167                 @message_rec_list = ($record);
 168                 my $lenhi;
 169                 my $lenlo;
 170                 ($mt, $lenhi, $lenlo) = unpack('CnC',
 171                                                substr($record->decrypt_data,
 172                                                       $recoffset));
 173                 $messlen = ($lenhi << 8) | $lenlo;
 174                 print "  Message type: $message_type{$mt}\n";
 175                 print "  Message Length: $messlen\n";
 176                 $startoffset = $recoffset;
 177                 $recoffset += 4;
 178                 $payload = "";
 179
 180                 if ($recoffset < $record->decrypt_len) {
 181                     #Some payload data is present in this record
 182                     if ($record->decrypt_len - $recoffset >= $messlen) {
 183                         #We can complete the message with this record
 184                         $payload .= substr($record->decrypt_data, $recoffset,
 185                                            $messlen);
 186                         $recoffset += $messlen;
 187                         push @message_frag_lens, $messlen;
 188                         $message = create_message($server, $mt, $payload,
 189                                                   $startoffset);
 190                         push @messages, $message;
 191
 192                         $payload = "";
 193                     } else {
 194                         #This is just part of the total message
 195                         $payload .= substr($record->decrypt_data, $recoffset,
 196                                            $record->decrypt_len - $recoffset);
 197                         $recoffset = $record->decrypt_len;
 198                         push @message_frag_lens, $recoffset;
 199                     }
 200                 }
 201             }
 202         }
 203     } elsif ($record->content_type == TLSProxy::Record::RT_APPLICATION_DATA) {
 204         print "  [ENCRYPTED APPLICATION DATA]\n";
 205         print "  [".$record->decrypt_data."]\n";
 206     } elsif ($record->content_type == TLSProxy::Record::RT_ALERT) {
 207         my ($alertlev, $alertdesc) = unpack('CC', $record->decrypt_data);
 208         #A CloseNotify from the client indicates we have finished successfully
 209         #(we assume)
 210         if (!$end && !$server && $alertlev == AL_LEVEL_WARN
 211             && $alertdesc == AL_DESC_CLOSE_NOTIFY) {
 212             $success = 1;
 213         }
 214         #All alerts end the test
 215         $end = 1;
 216     }
 217
 218     return @messages;
 219 }
 220
 221 #Function to work out which sub-class we need to create and then
 222 #construct it
 223 sub create_message
 224 {
 225     my ($server, $mt, $data, $startoffset) = @_;
 226     my $message;
 227
 228     #We only support ClientHello in this version...needs to be extended for
 229     #others
 230     if ($mt == MT_CLIENT_HELLO) {
 231         $message = TLSProxy::ClientHello->new(
 232             $server,
 233             $data,
 234             [@message_rec_list],
 235             $startoffset,
 236             [@message_frag_lens]
 237         );
 238         $message->parse();
 239     } elsif ($mt == MT_SERVER_HELLO) {
 240         $message = TLSProxy::ServerHello->new(
 241             $server,
 242             $data,
 243             [@message_rec_list],
 244             $startoffset,
 245             [@message_frag_lens]
 246         );
 247         $message->parse();
 248     } elsif ($mt == MT_SERVER_KEY_EXCHANGE) {
 249         $message = TLSProxy::ServerKeyExchange->new(
 250             $server,
 251             $data,
 252             [@message_rec_list],
 253             $startoffset,
 254             [@message_frag_lens]
 255         );
 256         $message->parse();
 257     } elsif ($mt == MT_NEW_SESSION_TICKET) {
 258         $message = TLSProxy::NewSessionTicket->new(
 259             $server,
 260             $data,
 261             [@message_rec_list],
 262             $startoffset,
 263             [@message_frag_lens]
 264         );
 265         $message->parse();
 266     } else {
 267         #Unknown message type
 268         $message = TLSProxy::Message->new(
 269             $server,
 270             $mt,
 271             $data,
 272             [@message_rec_list],
 273             $startoffset,
 274             [@message_frag_lens]
 275         );
 276     }
 277
 278     return $message;
 279 }
 280
 281 sub end
 282 {
 283     my $class = shift;
 284     return $end;
 285 }
 286 sub success
 287 {
 288     my $class = shift;
 289     return $success;
 290 }
 291 sub fail
 292 {
 293     my $class = shift;
 294     return !$success && $end;
 295 }
 296 sub new
 297 {
 298     my $class = shift;
 299     my ($server,
 300         $mt,
 301         $data,
 302         $records,
 303         $startoffset,
 304         $message_frag_lens) = @_;
 305
 306     my $self = {
 307         server => $server,
 308         data => $data,
 309         records => $records,
 310         mt => $mt,
 311         startoffset => $startoffset,
 312         message_frag_lens => $message_frag_lens
 313     };
 314
 315     return bless $self, $class;
 316 }
 317
 318 sub ciphersuite
 319 {
 320     my $class = shift;
 321     if (@_) {
 322       $ciphersuite = shift;
 323     }
 324     return $ciphersuite;
 325 }
 326
 327 #Update all the underlying records with the modified data from this message
 328 #Note: Does not currently support re-encrypting
 329 sub repack
 330 {
 331     my $self = shift;
 332     my $msgdata;
 333
 334     my $numrecs = $#{$self->records};
 335
 336     $self->set_message_contents();
 337
 338     my $lenhi;
 339     my $lenlo;
 340
 341     $lenlo = length($self->data) & 0xff;
 342     $lenhi = length($self->data) >> 8;
 343     $msgdata = pack('CnC', $self->mt, $lenhi, $lenlo).$self->data;
 344
 345     if ($numrecs == 0) {
 346         #The message is fully contained within one record
 347         my ($rec) = @{$self->records};
 348         my $recdata = $rec->decrypt_data;
 349
 350         my $old_length;
 351
 352         # We use empty message_frag_lens to indicates that pre-repacking,
 353         # the message wasn't present. The first fragment length doesn't include
 354         # the TLS header, so we need to check and compute the right length.
 355         if (@{$self->message_frag_lens}) {
 356             $old_length = ${$self->message_frag_lens}[0] +
 357               TLS_MESSAGE_HEADER_LENGTH;
 358         } else {
 359             $old_length = 0;
 360         }
 361
 362         my $prefix = substr($recdata, 0, $self->startoffset);
 363         my $suffix = substr($recdata, $self->startoffset + $old_length);
 364
 365         $rec->decrypt_data($prefix.($msgdata).($suffix));
 366         # TODO(openssl-team): don't keep explicit lengths.
 367         # (If a length override is ever needed to construct invalid packets,
 368         #  use an explicit override field instead.)
 369         $rec->decrypt_len(length($rec->decrypt_data));
 370         $rec->len($rec->len + length($msgdata) - $old_length);
 371         # Don't support re-encryption.
 372         $rec->data($rec->decrypt_data);
 373
 374         #Update the fragment len in case we changed it above
 375         ${$self->message_frag_lens}[0] = length($msgdata)
 376                                          - TLS_MESSAGE_HEADER_LENGTH;
 377         return;
 378     }
 379
 380     #Note we don't currently support changing a fragmented message length
 381     my $recctr = 0;
 382     my $datadone = 0;
 383     foreach my $rec (@{$self->records}) {
 384         my $recdata = $rec->decrypt_data;
 385         if ($recctr == 0) {
 386             #This is the first record
 387             my $remainlen = length($recdata) - $self->startoffset;
 388             $rec->data(substr($recdata, 0, $self->startoffset)
 389                        .substr(($msgdata), 0, $remainlen));
 390             $datadone += $remainlen;
 391         } elsif ($recctr + 1 == $numrecs) {
 392             #This is the last record
 393             $rec->data(substr($msgdata, $datadone));
 394         } else {
 395             #This is a middle record
 396             $rec->data(substr($msgdata, $datadone, length($rec->data)));
 397             $datadone += length($rec->data);
 398         }
 399         $recctr++;
 400     }
 401 }
 402
 403 #To be overridden by sub-classes
 404 sub set_message_contents
 405 {
 406 }
 407
 408 #Read only accessors
 409 sub server
 410 {
 411     my $self = shift;
 412     return $self->{server};
 413 }
 414
 415 #Read/write accessors
 416 sub mt
 417 {
 418     my $self = shift;
 419     if (@_) {
 420       $self->{mt} = shift;
 421     }
 422     return $self->{mt};
 423 }
 424 sub data
 425 {
 426     my $self = shift;
 427     if (@_) {
 428       $self->{data} = shift;
 429     }
 430     return $self->{data};
 431 }
 432 sub records
 433 {
 434     my $self = shift;
 435     if (@_) {
 436       $self->{records} = shift;
 437     }
 438     return $self->{records};
 439 }
 440 sub startoffset
 441 {
 442     my $self = shift;
 443     if (@_) {
 444       $self->{startoffset} = shift;
 445     }
 446     return $self->{startoffset};
 447 }
 448 sub message_frag_lens
 449 {
 450     my $self = shift;
 451     if (@_) {
 452       $self->{message_frag_lens} = shift;
 453     }
 454     return $self->{message_frag_lens};
 455 }
 456 sub encoded_length
 457 {
 458     my $self = shift;
 459     return TLS_MESSAGE_HEADER_LENGTH + length($self->data);
 460 }
 461
 462 1;