This file is indexed.

/usr/share/weechat/python/otr.py is in weechat-scripts 20131007-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   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
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
# -*- coding: utf-8 -*-
# otr - WeeChat script for Off-the-Record IRC messaging
#
# DISCLAIMER: To the best of my knowledge this script securely provides OTR
# messaging in WeeChat, but I offer no guarantee. Please report any security
# holes you find.
#
# Copyright (c) 2012 Matthew M. Boedicker <matthewm@boedicker.org>
#                    Nils Görs <weechatter@arcor.de>
#
# Report issues at https://github.com/mmb/weechat-otr
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from __future__ import unicode_literals

import collections
import cStringIO
import os
import re
import traceback

import weechat

import potr

SCRIPT_NAME = 'otr'
SCRIPT_DESC = 'Off-the-Record messaging for IRC'
SCRIPT_HELP = """%s

Quick start:

Add an OTR item to the status bar by adding '[otr]' to the config setting
weechat.bar.status.items. This will show you whether your current conversation
is encrypted, authenticated and logged. /set otr.* for OTR status bar
customization options.

Start a private conversation with a friend who has OTR: /query yourpeer hi

In the private chat buffer: /otr start

If you have not authenticated your peer yet, follow the instructions for
authentication.

View OTR policies for your peer: /otr policy

To end your private conversation: /otr finish
""" % SCRIPT_DESC

SCRIPT_AUTHOR = 'Matthew M. Boedicker'
SCRIPT_LICENCE = 'GPL3'
SCRIPT_VERSION = '1.1.0'

OTR_DIR_NAME = 'otr'

OTR_QUERY_RE = re.compile('\?OTR(\?|\??v[a-z\d]*\?)$')

POLICIES = {
    'allow_v2' : 'allow OTR protocol version 2',
    'require_encryption' : 'refuse to send unencrypted messages',
    'send_tag' : 'advertise your OTR capability using the whitespace tag',
    }

READ_ONLY_POLICIES = {
    'allow_v1' : False,
    }

IRC_PRIVMSG_RE = re.compile(r"""
(
    :
    (?P<from>
        (?P<from_nick>.+?)
        !
        (?P<from_user>.+?)
        @
        (?P<from_host>.+?)
    )
\ )?
PRIVMSG
\ (?P<to>.+?)
\ :
(?P<text>.+)
""", re.VERBOSE)

potr.proto.TaggedPlaintextOrig = potr.proto.TaggedPlaintext

class WeechatTaggedPlaintext(potr.proto.TaggedPlaintextOrig):
    """Patch potr.proto.TaggedPlaintext to not end plaintext tags in a space.

    When POTR adds OTR tags to plaintext it puts them at the end of the message.
    The tags end in a space which gets stripped off by WeeChat because it
    strips trailing spaces from commands. This causes OTR initiation to fail so
    the following code adds an extra tab at the end of the plaintext tags if
    they end in a space.
    """

    def __bytes__(self):
        # old style because parent class is old style
        result = potr.proto.TaggedPlaintextOrig.__bytes__(self).decode('utf-8')

        if result.endswith(' '):
            result = '%s\t' % result

        return result.encode('utf-8')

potr.proto.TaggedPlaintext = WeechatTaggedPlaintext

def command(buf, command_str):
    """Wrap weechat.command() with utf-8 encode."""
    debug(command_str)
    weechat.command(buf, command_str.encode('utf-8'))

def privmsg(server, nick, message):
    """Send a private message to a nick."""
    for line in message.split('\n'):
        command('', '/quote -server %s PRIVMSG %s :%s' % (server, nick, line))

def build_privmsg_in(fromm, to, msg):
    """Build an inbound IRC PRIVMSG command."""
    return ':%s PRIVMSG %s :%s' % (fromm, to, msg)

def prnt(buf, message):
    """Wrap weechat.prnt() with utf-8 encode."""
    weechat.prnt(buf, message.encode('utf-8'))

def debug(msg):
    """Send a debug message to the WeeChat core buffer."""
    debug_option = weechat.config_get(config_prefix('general.debug'))

    if weechat.config_boolean(debug_option):
        prnt('', ('%s debug\t%s' % (SCRIPT_NAME, unicode(msg))))

def current_user(server_name):
    """Get the nick and server of the current user on a server."""
    return irc_user(info_get('irc_nick', server_name), server_name)

def irc_user(nick, server):
    """Build an IRC user string from a nick and server."""
    return '%s@%s' % (nick, server)

def parse_irc_privmsg(message):
    """Parse an IRC PRIVMSG command and return a dictionary.

    Either the to_channel key or the to_nick key will be set depending on
    whether the message is to a nick or a channel. The other will be None.

    Example input:

    :nick!user@host PRIVMSG #weechat :message here

    Output:

    {'from': 'nick!user@host',
    'from_nick': 'nick',
    'from_user': 'user',
    'from_host': 'host',
    'to': '#weechat',
    'to_channel': '#weechat',
    'to_nick': None,
    'text': 'message here'}
    """

    match = IRC_PRIVMSG_RE.match(message)
    if match:
        result = match.groupdict()

        if result['to'].startswith('#'):
            result['to_channel'] = result['to']
            result['to_nick'] = None
        else:
            result['to_channel'] = None
            result['to_nick'] = result['to']

        return result

def has_otr_end(msg):
    """Return True if the message is the end of an OTR message."""
    return msg.endswith('.') or msg.endswith(',')

def first_instance(objs, klass):
    """Return the first object in the list that is an instance of a class."""
    for obj in objs:
        if isinstance(obj, klass):
            return obj

def config_prefix(option):
    """Add the config prefix to an option and return the full option name."""
    return '%s.%s' % (SCRIPT_NAME, option)

def config_color(option):
    """Get the color of a color config option."""
    return weechat.color(weechat.config_color(weechat.config_get(
            config_prefix('color.%s' % option))))

def config_string(option):
    """Get the string value of a config option with utf-8 decode."""
    return weechat.config_string(
        weechat.config_get(config_prefix(option))).decode('utf-8')

def buffer_get_string(buf, prop):
    """Wrap weechat.buffer_get_string() with utf-8 encode/decode."""
    return weechat.buffer_get_string(buf, prop.encode('utf-8')).decode('utf-8')

def buffer_is_private(buf):
    """Return True if a buffer is private."""
    return buffer_get_string(buf, 'localvar_type') == 'private'

def info_get(info_name, arguments):
    """Wrap weechat.info_get() with utf-8 encode/decode."""
    return weechat.info_get(info_name, arguments.encode('utf-8')).decode(
        'utf-8')

def default_peer_args(args):
    """Get the nick and server of a remote peer from command arguments or
    the current buffer.

    Passed in args are the [nick, server] slice of arguments from a command.
    If these are present, return them. If args is empty and the current buffer
    is private, return the remote nick and server of the current buffer.
    """
    result = None, None

    if len(args) == 2:
        result = tuple(args)
    else:
        buf = weechat.current_buffer()

        if buffer_is_private(buf):
            result = (
                buffer_get_string(buf, 'localvar_channel'),
                buffer_get_string(buf, 'localvar_server'))

    return result

class AccountDict(collections.defaultdict):
    """Dictionary that adds missing keys as IrcOtrAccount instances."""

    def __missing__(self, key):
        debug(('add account', key))
        self[key] = IrcOtrAccount(key)

        return self[key]

class Assembler:
    """Reassemble fragmented OTR messages.

    This does not deal with OTR fragmentation, which is handled by potr, but
    fragmentation of received OTR messages that are too large for IRC.
    """
    def __init__(self):
        self.clear()

    def add(self, data):
        """Add data to the buffer."""
        self.value += data

    def clear(self):
        """Empty the buffer."""
        self.value = ''

    def is_done(self):
        """Return True if the buffer is a complete message."""
        return self.is_query() or \
            not self.value.startswith(potr.proto.OTRTAG) or \
            has_otr_end(self.value)

    def get(self):
        """Return the current value of the buffer and empty it."""
        result = self.value
        self.clear()

        return result

    def is_query(self):
        """Return true if the buffer is an OTR query."""
        return OTR_QUERY_RE.match(self.value)

class IrcContext(potr.context.Context):
    """Context class for OTR over IRC."""

    def __init__(self, account, peername):
        super(IrcContext, self).__init__(account, peername)

        self.peer_nick, self.peer_server = peername.split('@')
        self.in_assembler = Assembler()
        self.in_otr_message = False
        self.in_smp = False
        self.smp_question = False

    def policy_config_option(self, policy):
        """Get the option name of a policy option for this context."""
        return config_prefix('.'.join([
                    'policy', self.peer_server, self.user.nick, self.peer_nick,
                    policy.lower()]))

    def getPolicy(self, key):
        """Get the value of a policy option for this context."""
        key_lower = key.lower()

        if key_lower in READ_ONLY_POLICIES:
            result = READ_ONLY_POLICIES[key_lower]
        else:
            option = weechat.config_get(self.policy_config_option(key))

            if option == '':
                option = weechat.config_get(
                    config_prefix('policy.default.%s' % key_lower))

            result = bool(weechat.config_boolean(option))

        debug(('getPolicy', key, result))

        return result

    def inject(self, msg, appdata=None):
        """Send a message to the remote peer."""
        if isinstance(msg, potr.proto.OTRMessage):
            msg = unicode(msg)
        else:
            msg = msg.decode('utf-8')

        debug(('inject', msg, 'len %d' % len(msg), appdata))

        privmsg(self.peer_server, self.peer_nick, msg)

    def setState(self, newstate):
        """Handle state transition."""
        debug(('state', self.state, newstate))

        if self.is_encrypted():
            if newstate == potr.context.STATE_ENCRYPTED:
                self.print_buffer(
                    'Private conversation has been refreshed.')
            elif newstate == potr.context.STATE_FINISHED:
                self.print_buffer(
                    """%s has ended the private conversation. You should do the same:
/otr finish %s %s
""" % (self.peer, self.peer_nick, self.peer_server))
        elif newstate == potr.context.STATE_ENCRYPTED:
            # unencrypted => encrypted
            trust = self.getCurrentTrust()
            if trust is None:
                fpr = str(self.getCurrentKey())
                self.print_buffer('New fingerprint: %s' % fpr)
                self.setCurrentTrust('')

            if bool(trust):
                self.print_buffer(
                    'Authenticated secured OTR conversation started.')
            else:
                self.print_buffer(
                    'Unauthenticated secured OTR conversation started.')
                self.print_buffer(self.verify_instructions())

        if self.state != potr.context.STATE_PLAINTEXT and \
                newstate == potr.context.STATE_PLAINTEXT:
            self.print_buffer('Private conversation ended.')

        super(IrcContext, self).setState(newstate)

    def maxMessageSize(self, appdata=None):
        """Return the max message size for this context."""
        # remove 'PRIVMSG <nick> :' from max message size
        result = self.user.maxMessageSize - 10 - len(self.peer_nick)
        debug('max message size %d' % result)

        return result

    def buffer(self):
        """Get the buffer for this context."""
        return info_get(
            'irc_buffer', '%s,%s' % (self.peer_server, self.peer_nick))

    def print_buffer(self, msg):
        """Print a message to the buffer for this context."""
        prnt(self.buffer(), '%s\t%s' % (SCRIPT_NAME, msg))

    def smp_finish(self, message):
        """Reset SMP state and send a message to the user."""
        self.in_smp = False
        self.smp_question = False

        self.user.saveTrusts()
        self.print_buffer(message)

    def handle_tlvs(self, tlvs):
        """Handle SMP states."""
        if tlvs:
            smp1q = first_instance(tlvs, potr.proto.SMP1QTLV)
            smp3 = first_instance(tlvs, potr.proto.SMP3TLV)
            smp4 = first_instance(tlvs, potr.proto.SMP4TLV)

            if self.in_smp and not self.smpIsValid():
                debug('SMP aborted')
                self.smp_finish('SMP aborted.')
            elif first_instance(tlvs, potr.proto.SMP1TLV):
                debug('SMP1')
                self.in_smp = True

                self.print_buffer(
                    """Peer has requested SMP verification.
Respond with: /otr smp respond %s %s <secret>""" % (
                        self.peer_nick, self.peer_server))
            elif smp1q:
                debug(('SMP1Q', smp1q.msg))
                self.in_smp = True
                self.smp_question = True

                self.print_buffer(
                    """Peer has requested SMP verification: %s
Respond with: /otr smp respond %s %s <answer>""" % (
                        smp1q.msg, self.peer_nick, self.peer_server))
            elif first_instance(tlvs, potr.proto.SMP2TLV):
                debug('SMP2')
                self.print_buffer('SMP progressing.')
            elif smp3 or smp4:
                if smp3:
                    debug('SMP3')
                elif smp4:
                    debug('SMP4')

                if self.smpIsSuccess():
                    self.smp_finish('SMP verification succeeded.')

                    if self.smp_question:
                        self.print_buffer(
                            """You may want to authenticate your peer by asking your own question:
/otr smp ask %s %s <secret> <question>
""" % (self.peer_nick, self.peer_server))
                else:
                    self.smp_finish('SMP verification failed.')

    def verify_instructions(self):
        """Generate verification instructions for user."""
        return """You can verify that this contact is who they claim to be in one of the following ways:

1) Verify each other's fingerprints using a secure channel:
  Your fingerprint : %(your_fingerprint)s
  %(peer)s's fingerprint : %(peer_fingerprint)s
  then use the command: /otr trust %(peer_nick)s %(peer_server)s

2) SMP pre-shared secret that you both know:
  /otr smp ask %(peer_nick)s %(peer_server)s <secret>

3) SMP pre-shared secret that you both know with a question:
  /otr smp ask %(peer_nick)s %(peer_server)s <secret> <question>
""" % dict(
            your_fingerprint=self.user.getPrivkey(),
            peer=self.peer,
            peer_fingerprint=potr.human_hash(
        self.crypto.theirPubkey.cfingerprint()),
            peer_nick=self.peer_nick,
            peer_server=self.peer_server,
            )

    def is_encrypted(self):
        """Return True if the conversation with this context's peer is
        currently encrypted."""
        return self.state == potr.context.STATE_ENCRYPTED

    def is_verified(self):
        """Return True if this context's peer is verified."""
        return bool(self.getCurrentTrust())

    def format_policies(self):
        """Return current policies for this context formatted as a string for
        the user."""
        buf = cStringIO.StringIO()

        buf.write('Current OTR policies for %s:\n' % self.peer)

        for policy, desc in sorted(POLICIES.iteritems()):
            buf.write('  %s (%s) : %s\n' % (
                    policy, desc,
                    { True : 'on', False : 'off'}[self.getPolicy(policy)]))

        buf.write('Change policies with: /otr policy NAME on|off')

        return buf.getvalue()

    def is_logged(self):
        """Return True if conversations with this context's peer are currently
        being logged to disk."""
        infolist = weechat.infolist_get('logger_buffer', '', '')

        buf = self.buffer()

        result = False

        while weechat.infolist_next(infolist):
            if weechat.infolist_pointer(infolist, 'buffer') == buf:
                result = bool(weechat.infolist_integer(infolist, 'log_enabled'))
                break

        weechat.infolist_free(infolist)

        return result

class IrcOtrAccount(potr.context.Account):
    """Account class for OTR over IRC."""

    contextclass = IrcContext

    PROTOCOL = 'irc'
    MAX_MSG_SIZE = 415

    def __init__(self, name):
        super(IrcOtrAccount, self).__init__(
            name, IrcOtrAccount.PROTOCOL, IrcOtrAccount.MAX_MSG_SIZE)

        self.nick, self.server = self.name.split('@')

        # IRC messages cannot have newlines, OTR query and "no plugin" text
        # need to be one message
        self.defaultQuery = self.defaultQuery.replace("\n", ' ')

        self.key_file_path = os.path.join(OTR_DIR, '%s.%s' % (name, 'key3'))
        self.fpr_file_path = os.path.join(OTR_DIR, '%s.%s' % (name, 'fpr'))

        self.load_trusts()

    def load_trusts(self):
        """Load trust data from the fingerprint file."""
        if os.path.exists(self.fpr_file_path):
            with open(self.fpr_file_path) as fpr_file:
                for line in fpr_file:
                    debug(('load trust check', line))

                    context, account, protocol, fpr, trust = \
                        line[:-1].split('\t')

                    if account == self.name and \
                            protocol == IrcOtrAccount.PROTOCOL:
                        debug(('set trust', context, fpr, trust))
                        self.setTrust(context, fpr, trust)

    def loadPrivkey(self):
        """Load key file."""
        debug(('load private key', self.key_file_path))

        if os.path.exists(self.key_file_path):
            with open(self.key_file_path, 'rb') as key_file:
                return potr.crypt.PK.parsePrivateKey(key_file.read())[0]

    def savePrivkey(self):
        """Save key file."""
        debug(('save private key', self.key_file_path))

        with open(self.key_file_path, 'wb') as key_file:
            key_file.write(self.getPrivkey().serializePrivateKey())

    def saveTrusts(self):
        """Save trusts."""
        with open(self.fpr_file_path, 'w') as fpr_file:
            for uid, trusts in self.trusts.iteritems():
                for fpr, trust in trusts.iteritems():
                    debug(('trust write', uid, self.name,
                           IrcOtrAccount.PROTOCOL, fpr, trust))
                    fpr_file.write('\t'.join(
                            (uid, self.name, IrcOtrAccount.PROTOCOL, fpr,
                             trust)))
                    fpr_file.write('\n')

    def end_all_private(self):
        """End all currently encrypted conversations."""
        for context in self.ctxs.itervalues():
            if context.is_encrypted():
                context.disconnect()

def message_in_cb(data, modifier, modifier_data, string):
    """Incoming message callback"""
    debug(('message_in_cb', data, modifier, modifier_data, string))

    parsed = parse_irc_privmsg(string.decode('utf-8'))
    debug(('parsed message', parsed))

    # skip processing messages to public channels
    if parsed['to_channel']:
        return string

    server = modifier_data.decode('utf-8')

    from_user = irc_user(parsed['from_nick'], server)
    local_user = current_user(server)

    context = ACCOUNTS[local_user].getContext(from_user)

    context.in_assembler.add(parsed['text'])

    result = ''

    if context.in_assembler.is_done():
        try:
            msg, tlvs = context.receiveMessage(context.in_assembler.get())

            debug(('receive', msg, tlvs))

            if msg:
                result = build_privmsg_in(
                    parsed['from'], parsed['to'], msg.decode('utf-8')).encode(
                    'utf-8')

            context.handle_tlvs(tlvs)
        except potr.context.ErrorReceived, e:
            context.print_buffer('Received OTR error: %s' % e.args[0].error)
        except potr.context.NotEncryptedError:
            context.print_buffer(
                'Received encrypted data but no private session established.')
        except potr.context.NotOTRMessage:
            result = string
        except potr.context.UnencryptedMessage, err:
            result = build_privmsg_in(
                parsed['from'], parsed['to'],
                'Unencrypted message received: %s' % (
                    err.args[0])).encode('utf-8')

    weechat.bar_item_update(SCRIPT_NAME)

    return result

def message_out_cb(data, modifier, modifier_data, string):
    """Outgoing message callback."""
    result = ''

    # If any exception is raised in this function, WeeChat will send the
    # outgoing message, which could be something that the user intended to be
    # encrypted. This paranoid exception handling ensures that the system
    # fails closed and not open.
    try:
        debug(('message_out_cb', data, modifier, modifier_data, string))

        parsed = parse_irc_privmsg(string.decode('utf-8'))
        debug(('parsed message', parsed))

        # skip processing messages to public channels
        if parsed['to_channel']:
            return string

        server = modifier_data.decode('utf-8')

        to_user = irc_user(parsed['to_nick'], server)
        local_user = current_user(server)

        context = ACCOUNTS[local_user].getContext(to_user)

        if parsed['text'].startswith(potr.proto.OTRTAG) and \
                not OTR_QUERY_RE.match(parsed['text']):
            if not has_otr_end(parsed['text']):
                debug('in OTR message')
                context.in_otr_message = True
            else:
                debug('complete OTR message')
            result = string
        elif context.in_otr_message:
            if has_otr_end(parsed['text']):
                context.in_otr_message = False
                debug('in OTR message end')
            result = string
        else:
            debug(('context send message', parsed['text'], parsed['to_nick'],
                   server))

            try:
                ret = context.sendMessage(
                    potr.context.FRAGMENT_SEND_ALL, parsed['text'].encode(
                        'utf-8'))

                if ret:
                    debug(('sendMessage returned', ret))
                    result = ('PRIVMSG %s :%s' % (
                            parsed['to_nick'], ret.decode('utf-8'))).encode(
                        'utf-8')
            except potr.context.NotEncryptedError, err:
                if err.args[0] == potr.context.EXC_FINISHED:
                    context.print_buffer(
                        """Your message was not sent. End your private conversation:\n/otr finish %s %s""" % (
                            parsed['to_nick'], server))
                else:
                    raise

        weechat.bar_item_update(SCRIPT_NAME)
    except:
        try:
            prnt('', traceback.format_exc())
            context.print_buffer(
                'Failed to send message. See core buffer for traceback.')
        except:
            pass

    return result

def shutdown():
    """Script unload callback."""
    debug('shutdown')

    weechat.config_write(CONFIG_FILE)

    for account in ACCOUNTS.itervalues():
        account.end_all_private()

    free_all_config()

    weechat.bar_item_remove(OTR_STATUSBAR)

    return weechat.WEECHAT_RC_OK

def command_cb(data, buf, args):
    """Parse and dispatch WeeChat OTR commands."""
    result = weechat.WEECHAT_RC_ERROR

    arg_parts = args.split(None, 5)

    if len(arg_parts) in (1, 3) and arg_parts[0] == 'start':
        nick, server = default_peer_args(arg_parts[1:3])

        if nick is not None and server is not None:
            context = ACCOUNTS[current_user(server)].getContext(
                irc_user(nick, server))

            context.print_buffer('Sending OTR query...')
            context.print_buffer(
                'To try OTR on all conversations with %s: /otr policy send_tag on' %
                context.peer)

            privmsg(server, nick, '?OTR?')

            result = weechat.WEECHAT_RC_OK
    elif len(arg_parts) in (1, 3) and arg_parts[0] == 'finish':
        nick, server = default_peer_args(arg_parts[1:3])

        if nick is not None and server is not None:
            context = ACCOUNTS[current_user(server)].getContext(
                irc_user(nick, server))
            context.disconnect()

            result = weechat.WEECHAT_RC_OK
    elif len(arg_parts) in (5, 6) and arg_parts[0] == 'smp':
        action = arg_parts[1]

        if action == 'respond':
            nick, server = arg_parts[2:4]
            secret = args.split(None, 4)[-1]

            context = ACCOUNTS[current_user(server)].getContext(
                irc_user(nick, server))
            context.smpGotSecret(secret)

            result = weechat.WEECHAT_RC_OK
        elif action == 'ask':
            nick, server, secret = arg_parts[2:5]

            if len(arg_parts) > 5:
                question = arg_parts[5]
            else:
                question = None

            context = ACCOUNTS[current_user(server)].getContext(
                irc_user(nick, server))

            try:
                context.smpInit(secret, question)
            except potr.context.NotEncryptedError:
                context.print_buffer(
                    'There is currently no encrypted session with %s.' % \
                        context.peer)
            else:
                result = weechat.WEECHAT_RC_OK
    elif len(arg_parts) in (1, 3) and arg_parts[0] == 'trust':
        nick, server = default_peer_args(arg_parts[1:3])

        if nick is not None and server is not None:
            context = ACCOUNTS[current_user(server)].getContext(
                irc_user(nick, server))

            if context.crypto.theirPubkey is not None:
                context.setCurrentTrust('verified')
                context.print_buffer('%s is now authenticated.' % context.peer)

                weechat.bar_item_update(SCRIPT_NAME)
            else:
                context.print_buffer(
                    'No fingerprint for %s. Start an OTR conversation first: /otr start' \
                        % context.peer)

            result = weechat.WEECHAT_RC_OK
    elif len(arg_parts) in (1, 3) and arg_parts[0] == 'policy':
        if len(arg_parts) == 1:
            nick, server = default_peer_args([])

            if nick is not None and server is not None:
                context = ACCOUNTS[current_user(server)].getContext(
                    irc_user(nick, server))

                context.print_buffer(context.format_policies())

                result = weechat.WEECHAT_RC_OK
        elif len(arg_parts) == 3 and arg_parts[1].lower() in POLICIES:
            nick, server = default_peer_args([])

            if nick is not None and server is not None:
                context = ACCOUNTS[current_user(server)].getContext(
                    irc_user(nick, server))

                policy_var = context.policy_config_option(arg_parts[1].lower())

                command('', '/set %s %s' % (policy_var, arg_parts[2]))

                context.print_buffer(context.format_policies())

                result = weechat.WEECHAT_RC_OK

    return result

def otr_statusbar_cb(data, item, window):
    """Update the statusbar."""
    if window:
        buf = weechat.window_get_pointer(window, 'buffer')
    else:
        # If the bar item is in a root bar that is not in a window, window
        # will be empty.
        buf = weechat.current_buffer()

    result = ''

    if buffer_is_private(buf):
        local_user = irc_user(
            buffer_get_string(buf, 'localvar_nick'),
            buffer_get_string(buf, 'localvar_server'))

        remote_user = irc_user(
            buffer_get_string(buf, 'localvar_channel'),
            buffer_get_string(buf, 'localvar_server'))

        context = ACCOUNTS[local_user].getContext(remote_user)

        encrypted_str = config_string('look.bar.state.encrypted')
        unencrypted_str = config_string('look.bar.state.unencrypted')
        authenticated_str = config_string('look.bar.state.authenticated')
        unauthenticated_str = config_string('look.bar.state.unauthenticated')
        logged_str = config_string('look.bar.state.logged')
        notlogged_str = config_string('look.bar.state.notlogged')

        bar_parts = []

        if context.is_encrypted():
            if encrypted_str:
                bar_parts.append(''.join([
                            config_color('status.encrypted'),
                            encrypted_str,
                            config_color('status.default')]))

            if context.is_verified():
                if authenticated_str:
                    bar_parts.append(''.join([
                                config_color('status.authenticated'),
                                authenticated_str,
                                config_color('status.default')]))
            elif unauthenticated_str:
                bar_parts.append(''.join([
                            config_color('status.unauthenticated'),
                            unauthenticated_str,
                            config_color('status.default')]))

            if context.is_logged():
                if logged_str:
                    bar_parts.append(''.join([
                                config_color('status.logged'),
                                logged_str,
                                config_color('status.default')]))
            elif notlogged_str:
                bar_parts.append(''.join([
                            config_color('status.notlogged'),
                            notlogged_str,
                            config_color('status.default')]))

        elif unencrypted_str:
            bar_parts.append(''.join([
                        config_color('status.unencrypted'),
                        unencrypted_str,
                        config_color('status.default')]))

        result = config_string('look.bar.state.separator').join(bar_parts)

        if result:
            result = '%s%s%s' % (
                config_color('status.default'),
                config_string('look.bar.prefix'), result)

    return result

def bar_config_update_cb(data, option):
    """Callback for updating the status bar when its config changes."""
    weechat.bar_item_update(SCRIPT_NAME)

    return weechat.WEECHAT_RC_OK

def policy_completion_cb(data, completion_item, buf, completion):
    """Callback for policy tab completion."""
    for policy in POLICIES:
        weechat.hook_completion_list_add(
            completion, policy, 0, weechat.WEECHAT_LIST_POS_SORT)

    return weechat.WEECHAT_RC_OK

def policy_create_option_cb(data, config_file, section, name, value):
    """Callback for creating a new policy option when the user sets one
    that doesn't exist."""
    weechat.config_new_option(
        config_file, section, name, 'boolean', '', '', 0, 0, value, value, 0,
        '', '', '', '', '', '')

    return weechat.WEECHAT_CONFIG_OPTION_SET_OK_CHANGED

def logger_level_update_cb(data, option, value):
    """Callback called when any logger level changes."""
    weechat.bar_item_update(SCRIPT_NAME)

    return weechat.WEECHAT_RC_OK

def buffer_switch_cb(data, signal, signal_data):
    """Callback for buffer switched.

    Used for updating the status bar item when it is in a root bar.
    """
    weechat.bar_item_update(SCRIPT_NAME)

    return weechat.WEECHAT_RC_OK

def init_config():
    """Set up configuration options and load config file."""
    global CONFIG_FILE
    CONFIG_FILE = weechat.config_new(SCRIPT_NAME, 'config_reload_cb', '')

    global CONFIG_SECTIONS
    CONFIG_SECTIONS = {}

    CONFIG_SECTIONS['general'] = weechat.config_new_section(
        CONFIG_FILE, 'general', 0, 0, '', '', '', '', '', '', '', '', '', '')

    for option, typ, desc, default in [
        ('debug', 'boolean', 'OTR script debugging', 'off'),
        ]:
        weechat.config_new_option(
            CONFIG_FILE, CONFIG_SECTIONS['general'], option, typ, desc, '', 0,
            0, default, default, 0, '', '', '', '', '', '')

    CONFIG_SECTIONS['color'] = weechat.config_new_section(
        CONFIG_FILE, 'color', 0, 0, '', '', '', '', '', '', '', '', '', '')

    for option, desc, default, update_cb in [
        ('status.default', 'status bar default color', 'default',
         'bar_config_update_cb'),
        ('status.encrypted', 'status bar encrypted indicator color', 'green',
         'bar_config_update_cb'),
        ('status.unencrypted', 'status bar unencrypted indicator color',
         'lightred', 'bar_config_update_cb'),
        ('status.authenticated', 'status bar authenticated indicator color',
         'green', 'bar_config_update_cb'),
        ('status.unauthenticated', 'status bar unauthenticated indicator color',
         'lightred', 'bar_config_update_cb'),
        ('status.logged', 'status bar logged indicator color', 'lightred',
         'bar_config_update_cb'),
        ('status.notlogged', 'status bar not logged indicator color',
         'green', 'bar_config_update_cb'),
        ]:
        weechat.config_new_option(
            CONFIG_FILE, CONFIG_SECTIONS['color'], option, 'color', desc, '', 0,
            0, default, default, 0, '', '', update_cb, '', '', '')

    CONFIG_SECTIONS['look'] = weechat.config_new_section(
        CONFIG_FILE, 'look', 0, 0, '', '', '', '', '', '', '', '', '', '')

    for option, desc, default, update_cb in [
        ('bar.prefix', 'prefix for OTR status bar item', 'OTR:',
         'bar_config_update_cb'),
        ('bar.state.encrypted',
         'shown in status bar when conversation is encrypted', 'SEC',
         'bar_config_update_cb'),
        ('bar.state.unencrypted',
         'shown in status bar when conversation is not encrypted', '!SEC',
         'bar_config_update_cb'),
        ('bar.state.authenticated',
         'shown in status bar when peer is authenticated', 'AUTH',
         'bar_config_update_cb'),
        ('bar.state.unauthenticated',
         'shown in status bar when peer is not authenticated', '!AUTH',
         'bar_config_update_cb'),
        ('bar.state.logged',
         'shown in status bar when peer conversation is being logged to disk',
         'LOG',
         'bar_config_update_cb'),
        ('bar.state.notlogged',
         'shown in status bar when peer conversation is not being logged to disk',
         '!LOG',
         'bar_config_update_cb'),
        ('bar.state.separator', 'separator for states in the status bar', ',',
         'bar_config_update_cb'),
        ]:
        weechat.config_new_option(
            CONFIG_FILE, CONFIG_SECTIONS['look'], option, 'string', desc, '',
            0, 0, default, default, 0, '', '', update_cb, '', '', '')

    CONFIG_SECTIONS['policy'] = weechat.config_new_section(
        CONFIG_FILE, 'policy', 1, 1, '', '', '', '', '', '',
        'policy_create_option_cb', '', '', '')

    for option, desc, default in [
        ('default.allow_v2', 'default allow OTR v2 policy', 'on'),
        ('default.require_encryption', 'default require encryption policy',
         'off'),
        ('default.send_tag', 'default send tag policy', 'off'),
        ]:
        weechat.config_new_option(
            CONFIG_FILE, CONFIG_SECTIONS['policy'], option, 'boolean', desc, '',
            0, 0, default, default, 0, '', '', '', '', '', '')

    weechat.config_read(CONFIG_FILE)

def config_reload_cb(data, config_file):
    """/reload callback to reload config from file."""
    free_all_config()
    init_config()

    return weechat.WEECHAT_CONFIG_READ_OK

def free_all_config():
    """Free all config options, sections and config file."""
    for section in CONFIG_SECTIONS.itervalues():
        weechat.config_section_free_options(section)
        weechat.config_section_free(section)

    weechat.config_free(CONFIG_FILE)

def create_dir():
    """Create the OTR subdirectory in the WeeChat config directory if it does
    not exist."""
    if not os.path.exists(OTR_DIR):
        weechat.mkdir_home(OTR_DIR_NAME, 0700)

if weechat.register(
    SCRIPT_NAME, SCRIPT_AUTHOR, SCRIPT_VERSION, SCRIPT_LICENCE, SCRIPT_DESC,
    'shutdown', ''):
    init_config()

    OTR_DIR = os.path.join(info_get('weechat_dir', ''), OTR_DIR_NAME)
    create_dir()

    ACCOUNTS = AccountDict()

    weechat.hook_modifier('irc_in_privmsg', 'message_in_cb', '')
    weechat.hook_modifier('irc_out_privmsg', 'message_out_cb', '')

    weechat.hook_command(
        SCRIPT_NAME, SCRIPT_HELP,
        'start [NICK SERVER] || '
        'finish [NICK SERVER] || '
        'smp ask NICK SERVER SECRET [QUESTION] || '
        'smp respond NICK SERVER SECRET || '
        'trust [NICK SERVER] || '
        'policy [POLICY on|off]',
        '',
        'start %(nick) %(irc_servers) %-||'
        'finish %(nick) %(irc_servers) %-||'
        'smp ask|respond %(nick) %(irc_servers) %-||'
        'trust %(nick) %(irc_servers) %-||'
        'policy %(otr_policy) on|off %-||',
        'command_cb',
        '')

    weechat.hook_completion(
        'otr_policy', 'OTR policies', 'policy_completion_cb', '')

    weechat.hook_config('logger.level.irc.*', 'logger_level_update_cb', '')

    weechat.hook_signal('buffer_switch', 'buffer_switch_cb', '')

    OTR_STATUSBAR = weechat.bar_item_new(SCRIPT_NAME, 'otr_statusbar_cb', '')
    weechat.bar_item_update(SCRIPT_NAME)