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
|
# Copyright 2011-2012 Kjell Braden <afflux@pentabarf.de>
#
# This file is part of the python-potr library.
#
# python-potr is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# any later version.
#
# python-potr 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this library. If not, see <http://www.gnu.org/licenses/>.
# some python3 compatibilty
from __future__ import unicode_literals
import base64
import struct
from potr.utils import pack_mpi, read_mpi, pack_data, read_data, unpack
OTRTAG = b'?OTR'
MESSAGE_TAG_BASE = b' \t \t\t\t\t \t \t \t '
MESSAGE_TAGS = {
1:b' \t \t \t ',
2:b' \t\t \t ',
3:b' \t\t \t\t',
}
MSGTYPE_NOTOTR = 0
MSGTYPE_TAGGEDPLAINTEXT = 1
MSGTYPE_QUERY = 2
MSGTYPE_DH_COMMIT = 3
MSGTYPE_DH_KEY = 4
MSGTYPE_REVEALSIG = 5
MSGTYPE_SIGNATURE = 6
MSGTYPE_V1_KEYEXCH = 7
MSGTYPE_DATA = 8
MSGTYPE_ERROR = 9
MSGTYPE_UNKNOWN = -1
MSGFLAGS_IGNORE_UNREADABLE = 1
tlvClasses = {}
messageClasses = {}
hasByteStr = bytes == str
def bytesAndStrings(cls):
if hasByteStr:
cls.__str__ = lambda self: self.__bytes__()
else:
cls.__str__ = lambda self: str(self.__bytes__(), encoding='ascii')
return cls
def registermessage(cls):
if not hasattr(cls, 'parsePayload'):
raise TypeError('registered message types need parsePayload()')
messageClasses[cls.version, cls.msgtype] = cls
return cls
def registertlv(cls):
if not hasattr(cls, 'parsePayload'):
raise TypeError('registered tlv types need parsePayload()')
if cls.typ is None:
raise TypeError('registered tlv type needs type ID')
tlvClasses[cls.typ] = cls
return cls
def getslots(cls, base):
''' helper to collect all the message slots from ancestors '''
clss = [cls]
for cls in clss:
if cls == base:
continue
clss.extend(cls.__bases__)
for slot in cls.__slots__:
yield slot
@bytesAndStrings
class OTRMessage(object):
__slots__ = ['payload']
version = 0x0002
msgtype = 0
def __eq__(self, other):
if not isinstance(other, self.__class__):
return False
for slot in getslots(self.__class__, OTRMessage):
if getattr(self, slot) != getattr(other, slot):
return False
return True
def __neq__(self, other):
return not self.__eq__(other)
class Error(OTRMessage):
__slots__ = ['error']
def __init__(self, error):
super(Error, self).__init__()
self.error = error
def __repr__(self):
return '<proto.Error(%r)>' % self.error
def __bytes__(self):
return b'?OTR Error:' + self.error
class Query(OTRMessage):
__slots__ = ['versions']
def __init__(self, versions=set()):
super(Query, self).__init__()
self.versions = versions
@classmethod
def parse(cls, data):
if not isinstance(data, bytes):
raise TypeError('can only parse bytes')
udata = data.decode('ascii', errors='replace')
versions = set()
if len(udata) > 0 and udata[0] == '?':
udata = udata[1:]
versions.add(1)
if len(udata) > 0 and udata[0] == 'v':
versions.update(( int(c) for c in udata if c.isdigit() ))
return cls(versions)
def __repr__(self):
return '<proto.Query(versions=%r)>' % (self.versions)
def __bytes__(self):
d = b'?OTR'
if 1 in self.versions:
d += b'?'
d += b'v'
# in python3 there is only int->unicode conversion
# so I convert to unicode and encode it to a byte string
versions = [ '%d' % v for v in self.versions if v != 1 ]
d += ''.join(versions).encode('ascii')
d += b'?'
return d
class TaggedPlaintext(Query):
__slots__ = ['msg']
def __init__(self, msg, versions):
super(TaggedPlaintext, self).__init__(versions)
self.msg = msg
def __bytes__(self):
data = self.msg + MESSAGE_TAG_BASE
for v in self.versions:
data += MESSAGE_TAGS[v]
return data
def __repr__(self):
return '<proto.TaggedPlaintext(versions={versions!r},msg={msg!r})>' \
.format(versions=self.versions, msg=self.msg)
@classmethod
def parse(cls, data):
tagPos = data.find(MESSAGE_TAG_BASE)
if tagPos < 0:
raise TypeError(
'this is not a tagged plaintext ({0!r:.20})'.format(data))
tags = [ data[i:i+8] for i in range(tagPos, len(data), 8) ]
versions = set([ version for version, tag in MESSAGE_TAGS.items() if tag
in tags ])
return TaggedPlaintext(data[:tagPos], versions)
class GenericOTRMessage(OTRMessage):
__slots__ = ['data']
fields = []
def __init__(self, *args):
super(GenericOTRMessage, self).__init__()
if len(args) != len(self.fields):
raise TypeError('%s needs %d arguments, got %d' %
(self.__class__.__name__, len(self.fields), len(args)))
super(GenericOTRMessage, self).__setattr__('data',
dict(zip((f[0] for f in self.fields), args)))
def __getattr__(self, attr):
if attr in self.data:
return self.data[attr]
raise AttributeError(
"'{t!r}' object has no attribute '{attr!r}'".format(attr=attr,
t=self.__class__.__name__))
def __setattr__(self, attr, val):
if attr in self.__slots__:
super(GenericOTRMessage, self).__setattr__(attr, val)
else:
self.__getattr__(attr) # existence check
self.data[attr] = val
def __bytes__(self):
data = struct.pack(b'!HB', self.version, self.msgtype) \
+ self.getPayload()
return b'?OTR:' + base64.b64encode(data) + b'.'
def __repr__(self):
name = self.__class__.__name__
data = ''
for k, _ in self.fields:
data += '%s=%r,' % (k, self.data[k])
return '<proto.%s(%s)>' % (name, data)
@classmethod
def parsePayload(cls, data):
data = base64.b64decode(data)
args = []
for _, ftype in cls.fields:
if ftype == 'data':
value, data = read_data(data)
elif isinstance(ftype, bytes):
value, data = unpack(ftype, data)
elif isinstance(ftype, int):
value, data = data[:ftype], data[ftype:]
args.append(value)
return cls(*args)
def getPayload(self, *ffilter):
payload = b''
for k, ftype in self.fields:
if k in ffilter:
continue
if ftype == 'data':
payload += pack_data(self.data[k])
elif isinstance(ftype, bytes):
payload += struct.pack(ftype, self.data[k])
else:
payload += self.data[k]
return payload
class AKEMessage(GenericOTRMessage):
__slots__ = []
@registermessage
class DHCommit(AKEMessage):
__slots__ = []
msgtype = 0x02
fields = [('encgx', 'data'), ('hashgx', 'data'), ]
@registermessage
class DHKey(AKEMessage):
__slots__ = []
msgtype = 0x0a
fields = [('gy', 'data'), ]
@registermessage
class RevealSig(AKEMessage):
__slots__ = []
msgtype = 0x11
fields = [('rkey', 'data'), ('encsig', 'data'), ('mac', 20),]
def getMacedData(self):
p = self.encsig
return struct.pack(b'!I', len(p)) + p
@registermessage
class Signature(AKEMessage):
__slots__ = []
msgtype = 0x12
fields = [('encsig', 'data'), ('mac', 20)]
def getMacedData(self):
p = self.encsig
return struct.pack(b'!I', len(p)) + p
@registermessage
class DataMessage(GenericOTRMessage):
__slots__ = []
msgtype = 0x03
fields = [('flags', b'!B'), ('skeyid', b'!I'), ('rkeyid', b'!I'),
('dhy', 'data'), ('ctr', 8), ('encmsg', 'data'), ('mac', 20),
('oldmacs', 'data'), ]
def getMacedData(self):
return struct.pack(b'!HB', self.version, self.msgtype) + \
self.getPayload('mac', 'oldmacs')
@bytesAndStrings
class TLV(object):
__slots__ = []
typ = None
def getPayload(self):
raise NotImplementedError
def __repr__(self):
val = self.getPayload()
return '<{cls}(typ={t},len={l},val={v!r})>'.format(t=self.typ,
l=len(val), v=val, cls=self.__class__.__name__)
def __bytes__(self):
val = self.getPayload()
return struct.pack(b'!HH', self.typ, len(val)) + val
@classmethod
def parse(cls, data):
if not data:
return []
typ, length, data = unpack(b'!HH', data)
return [tlvClasses[typ].parsePayload(data[:length])] \
+ cls.parse(data[length:])
def __eq__(self, other):
if not isinstance(other, self.__class__):
return False
for slot in getslots(self.__class__, TLV):
if getattr(self, slot) != getattr(other, slot):
return False
return True
def __neq__(self, other):
return not self.__eq__(other)
@registertlv
class PaddingTLV(TLV):
typ = 0
__slots__ = ['padding']
def __init__(self, padding):
super(PaddingTLV, self).__init__()
self.padding = padding
def getPayload(self):
return self.padding
@classmethod
def parsePayload(cls, data):
return cls(data)
@registertlv
class DisconnectTLV(TLV):
typ = 1
def __init__(self):
super(DisconnectTLV, self).__init__()
def getPayload(self):
return b''
@classmethod
def parsePayload(cls, data):
if len(data) > 0:
raise TypeError('DisconnectTLV must not contain data. got {0!r}'
.format(data))
return cls()
class SMPTLV(TLV):
__slots__ = ['mpis']
dlen = None
def __init__(self, mpis=None):
super(SMPTLV, self).__init__()
if mpis is None:
mpis = []
if self.dlen is None:
raise TypeError('no amount of mpis specified in dlen')
if len(mpis) != self.dlen:
raise TypeError('expected {0} mpis, got {1}'
.format(self.dlen, len(mpis)))
self.mpis = mpis
def getPayload(self):
d = struct.pack(b'!I', len(self.mpis))
for n in self.mpis:
d += pack_mpi(n)
return d
@classmethod
def parsePayload(cls, data):
mpis = []
if cls.dlen > 0:
count, data = unpack(b'!I', data)
for _ in range(count):
n, data = read_mpi(data)
mpis.append(n)
if len(data) > 0:
raise TypeError('too much data for {0} mpis'.format(cls.dlen))
return cls(mpis)
@registertlv
class SMP1TLV(SMPTLV):
typ = 2
dlen = 6
@registertlv
class SMP1QTLV(SMPTLV):
typ = 7
dlen = 6
__slots__ = ['msg']
def __init__(self, msg, mpis):
self.msg = msg
super(SMP1QTLV, self).__init__(mpis)
def getPayload(self):
return self.msg + b'\0' + super(SMP1QTLV, self).getPayload()
@classmethod
def parsePayload(cls, data):
msg, data = data.split(b'\0', 1)
mpis = SMP1TLV.parsePayload(data).mpis
return cls(msg, mpis)
@registertlv
class SMP2TLV(SMPTLV):
typ = 3
dlen = 11
@registertlv
class SMP3TLV(SMPTLV):
typ = 4
dlen = 8
@registertlv
class SMP4TLV(SMPTLV):
typ = 5
dlen = 3
@registertlv
class SMPABORTTLV(SMPTLV):
typ = 6
dlen = 0
def getPayload(self):
return b''
@registertlv
class ExtraKeyTLV(TLV):
typ = 8
__slots__ = ['appid', 'appdata']
def __init__(self, appid, appdata):
super(ExtraKeyTLV, self).__init__()
self.appid = appid
self.appdata = appdata
if appdata is None:
self.appdata = b''
def getPayload(self):
return self.appid + self.appdata
@classmethod
def parsePayload(cls, data):
return cls(data[:4], data[4:])
|