This file is indexed.

/usr/share/pyshared/ufw/common.py is in python-ufw 0.33-2.

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
'''common.py: common classes for ufw'''
#
# Copyright 2008-2011 Canonical Ltd.
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License version 3,
#    as published by the Free Software Foundation.
#
#    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/>.
#

import re
import socket
import ufw.util
from ufw.util import debug

programName = "ufw"
state_dir = "/lib/ufw"
share_dir = "/usr/share/ufw"
trans_dir = share_dir
config_dir = "/etc"
prefix_dir = "/usr"
iptables_dir = "/sbin"

class UFWError(Exception):
    '''This class represents ufw exceptions'''
    def __init__(self, value):
        self.value = value

    def __str__(self):
        return repr(self.value)


class UFWRule:
    '''This class represents firewall rules'''
    def __init__(self, action, protocol, dport="any", dst="0.0.0.0/0",
                 sport="any", src="0.0.0.0/0", direction="in"):
        # Be sure to update dup_rule accordingly...
        self.remove = False
        self.updated = False
        self.v6 = False
        self.dst = ""
        self.src = ""
        self.dport = ""
        self.sport = ""
        self.protocol = ""
        self.multi = False
        self.dapp = ""
        self.sapp = ""
        self.action = ""
        self.position = 0
        self.logtype = ""
        self.interface_in = ""
        self.interface_out = ""
        self.direction = ""
        try:
            self.set_action(action)
            self.set_protocol(protocol)
            self.set_port(dport)
            self.set_port(sport, "src")
            self.set_src(src)
            self.set_dst(dst)
            self.set_direction(direction)
        except UFWError:
            raise

    def __str__(self):
        return self.format_rule()

    def _get_attrib(self):
        '''Print rule to stdout'''
        res = "'%s'" % (self)
        for k in self.__dict__:
            res += ", %s=%s" % (k, self.__dict__[k])
        return res

    def dup_rule(self):
        '''Return a duplicate of a rule'''
        rule = UFWRule(self.action, self.protocol)
        rule.remove = self.remove
        rule.updated = self.updated
        rule.v6 = self.v6
        rule.dst = self.dst
        rule.src = self.src
        rule.dport = self.dport
        rule.sport = self.sport
        rule.multi = self.multi
        rule.dapp = self.dapp
        rule.sapp = self.sapp
        rule.position = self.position
        rule.logtype = self.logtype
        rule.interface_in = self.interface_in
        rule.interface_out = self.interface_out
        rule.direction = self.direction

        return rule

    def format_rule(self):
        '''Format rule for later parsing'''
        rule_str = ""

        if self.interface_in != "":
            rule_str += " -i %s" % (self.interface_in)
        if self.interface_out != "":
            rule_str += " -o %s" % (self.interface_out)

        # Protocol is handled below
        if self.protocol == "any":
            rule_str += " -p all"
        else:
            rule_str += " -p " + self.protocol

            if self.multi:
                rule_str += " -m multiport"
                if self.dport != "any" and self.sport != "any":
                    rule_str += " --dports " + self.dport
                    rule_str += " -m multiport"
                    rule_str += " --sports " + self.sport
                elif self.dport != "any":
                    rule_str += " --dports " + self.dport
                elif self.sport != "any":
                    rule_str += " --sports " + self.sport

        if self.dst != "0.0.0.0/0" and self.dst != "::/0":
            rule_str += " -d " + self.dst
        if not self.multi and self.dport != "any":
            rule_str += " --dport " + self.dport
        if self.src != "0.0.0.0/0" and self.src != "::/0":
            rule_str += " -s " + self.src
        if not self.multi and self.sport != "any":
            rule_str += " --sport " + self.sport

        lstr = ""
        if self.logtype != "":
            lstr = "_" + self.logtype
        if self.action == "allow":
            rule_str += " -j ACCEPT%s" % (lstr)
        elif self.action == "reject":
            rule_str += " -j REJECT%s" % (lstr)
            if self.protocol == "tcp":
                # follow TCP's default and send RST
                rule_str += " --reject-with tcp-reset"
        elif self.action == "limit":
            # Caller needs to change this
            rule_str += " -j LIMIT%s" % (lstr)
        else:
            rule_str += " -j DROP%s" % (lstr)

        if self.dapp != "" or self.sapp != "":
            # Format the comment string, and quote it just in case
            comment = "-m comment --comment '"
            pat_space = re.compile(' ')
            if self.dapp != "":
                comment += "dapp_" + pat_space.sub('%20', self.dapp)
            if self.dapp != "" and self.sapp != "":
                comment += ","
            if self.sapp != "":
                comment += "sapp_" + pat_space.sub('%20', self.sapp)
            comment += "'"

            rule_str += " " + comment

        return rule_str.strip()

    def set_action(self, action):
        '''Sets action of the rule'''
        tmp = action.lower().split('_')
        if tmp[0] == "allow" or tmp[0] == "reject" or tmp[0] == "limit":
            self.action = tmp[0]
        else:
            self.action = "deny"

        logtype = ""
        if len(tmp) > 1:
            logtype = tmp[1]
        self.set_logtype(logtype)

    def set_port(self, port, loc="dst"):
        '''Sets port and location (destination or source) of the rule'''
        err_msg = _("Bad port '%s'") % (port)
        if port == "any":
            pass
        elif loc == "dst" and self.dapp:
            pass
        elif loc == "src" and self.sapp:
            pass
        elif re.match(r'^[,:]', port) or re.match(r'[,:]$', port):
            raise UFWError(err_msg)
        elif (port.count(',') + port.count(':')) > 14:
            # Limitation of iptables
            raise UFWError(err_msg)
        else:
            ports = port.split(',')
            if len(ports) < 1:
                raise UFWError(err_msg)
            elif len(ports) > 1:
                self.multi = True

            tmp = ""
            for p in ports:
                if re.match(r'^\d+:\d+$', p):
                    # Port range
                    self.multi = True
                    ran = p.split(':')
                    if len(ran) != 2:
                        raise UFWError(err_msg)
                    for q in ran:
                        if int(q) < 1 or int(q) > 65535:
                            raise UFWError(err_msg)
                    if int(ran[0]) >= int(ran[1]):
                        raise UFWError(err_msg)
                elif re.match('^\d+$', p):
                    if int(p) < 1 or int(p) > 65535:
                        raise UFWError(err_msg)
                elif re.match(r'^\w[\w\-]+', p):
                    try:
                        p = socket.getservbyname(p)
                    except Exception:
                        raise UFWError(err_msg)
                else:
                    raise UFWError(err_msg)

                if tmp:
                    tmp += "," + str(p)
                else:
                    tmp = str(p)

            port = tmp

        if loc == "src":
            self.sport = str(port)
        else:
            self.dport = str(port)

    def set_protocol(self, protocol):
        '''Sets protocol of the rule'''
        if protocol == "tcp" or \
           protocol == "udp" or \
           protocol == "ipv6" or \
           protocol == "esp" or \
           protocol == "ah" or \
           protocol == "any":
            self.protocol = protocol
        else:
            err_msg = _("Unsupported protocol '%s'") % (protocol)
            raise UFWError(err_msg)

    def _fix_anywhere(self):
        '''Adjusts src and dst based on v6'''
        if self.v6:
            if self.dst and (self.dst == "any" or self.dst == "0.0.0.0/0"):
                self.dst = "::/0"
            if self.src and (self.src == "any" or self.src == "0.0.0.0/0"):
                self.src = "::/0"
        else:
            if self.dst and (self.dst == "any" or self.dst == "::/0"):
                self.dst = "0.0.0.0/0"
            if self.src and (self.src == "any" or self.src == "::/0"):
                self.src = "0.0.0.0/0"

    def set_v6(self, v6):
        '''Sets whether this is ipv6 rule, and adjusts src and dst
           accordingly.
        '''
        self.v6 = v6
        self._fix_anywhere()

    def set_src(self, addr):
        '''Sets source address of rule'''
        tmp = addr.lower()

        if tmp != "any" and not ufw.util.valid_address(tmp, "any"):
            err_msg = _("Bad source address")
            raise UFWError(err_msg)
        self.src = tmp
        self._fix_anywhere()

    def set_dst(self, addr):
        '''Sets destination address of rule'''
        tmp = addr.lower()

        if tmp != "any" and not ufw.util.valid_address(tmp, "any"):
            err_msg = _("Bad destination address")
            raise UFWError(err_msg)
        self.dst = tmp
        self._fix_anywhere()

    def set_interface(self, if_type, name):
        '''Sets an interface for rule'''
        if if_type != "in" and if_type != "out":
            err_msg = _("Bad interface type")
            raise UFWError(err_msg)

        if not re.match(r'^[a-zA-Z][a-zA-Z0-9:]*[a-zA-Z0-9]', str(name)):
            err_msg = _("Bad interface name")
            raise UFWError(err_msg)

        if ':' in str(name):
            err_msg = _("Bad interface name: can't use interface aliases")
            raise UFWError(err_msg)

        if if_type == "in":
            self.interface_in = name
        else:
            self.interface_out = name

    def set_position(self, num):
        '''Sets the position of the rule'''
        if not re.match(r'^[0-9]+', str(num)):
            err_msg = _("Insert position '%s' is not a valid position") % (num)
            raise UFWError(err_msg)
        self.position = int(num)

    def set_logtype(self, logtype):
        '''Sets logtype of the rule'''
        if logtype.lower() == "log" or logtype.lower() == "log-all" or \
           logtype == "":
            self.logtype = logtype.lower()
        else:
            err_msg = _("Invalid log type '%s'") % (logtype)
            raise UFWError(err_msg)

    def set_direction(self, direction):
        '''Sets direction of the rule'''
        if direction == "in" or direction == "out":
            self.direction = direction
        else:
            err_msg = _("Unsupported direction '%s'") % (direction)
            raise UFWError(err_msg)

    def normalize(self):
        '''Normalize src and dst to standard form'''
        changed = False
        if self.src:
            try:
                (self.src, changed) = ufw.util.normalize_address(self.src, \
                                                                 self.v6)
            except Exception:
                raise

        if changed:
            self.updated = changed

        if self.dst:
            try:
                (self.dst, changed) = ufw.util.normalize_address(self.dst, \
                                                                   self.v6)
            except Exception:
                err_msg = _("Could not normalize destination address")
                raise UFWError(err_msg)

        if self.dport:
            ports = self.dport.split(',')
            ufw.util.human_sort(ports)
            self.dport = ','.join(ports)

        if self.sport:
            ports = self.sport.split(',')
            ufw.util.human_sort(ports)
            self.sport = ','.join(ports)

        if changed:
            self.updated = changed

    def match(x, y):
        '''Check if rules match
        Return codes:
          0  match
          1  no match
         -1  match all but action
        '''
        if not x or not y:
            raise ValueError()

        dbg_msg = "No match '%s' '%s'" % (x, y)
        if x.dport != y.dport:
            debug(dbg_msg)
            return 1
        if x.sport != y.sport:
            debug(dbg_msg)
            return 1
        if x.protocol != y.protocol:
            debug(dbg_msg)
            return 1
        if x.src != y.src:
            debug(dbg_msg)
            return 1
        if x.dst != y.dst:
            debug(dbg_msg)
            return 1
        if x.v6 != y.v6:
            debug(dbg_msg)
            return 1
        if x.dapp != y.dapp:
            debug(dbg_msg)
            return 1
        if x.sapp != y.sapp:
            debug(dbg_msg)
            return 1
        if x.interface_in != y.interface_in:
            debug(dbg_msg)
            return 1
        if x.interface_out != y.interface_out:
            debug(dbg_msg)
            return 1
        if x.direction != y.direction:
            debug(dbg_msg)
            return 1
        if x.action == y.action and x.logtype == y.logtype:
            dbg_msg = _("Found exact match")
            debug(dbg_msg)
            return 0

        dbg_msg = _("Found non-action/non-logtype match " \
                    "(%(xa)s/%(ya)s %(xl)s/%(yl)s)") % \
                    ({'xa': x.action, 'ya': y.action, \
                      'xl': x.logtype, 'yl': y.logtype})
        debug(dbg_msg)
        return -1

    def fuzzy_dst_match(x, y):
        '''This will match if x is more specific than y. Eg, for protocol if x
	   is tcp and y is all or for address if y is a network and x is a
           subset of y (where x is either an address or network). Returns:

            0  match
            1  no match
           -1  fuzzy match

           This is a fuzzy destination match, so source ports or addresses
           are not considered, and (currently) only incoming.
        '''
        def _match_ports(test_p, to_match):
            '''Returns True if p is an exact match or within a multi rule'''
            for port in to_match.split(','):
                if test_p == port:
                    return True
                if ':' in port:
                    (low, high) = port.split(':')
                    if int(test_p) >= int(low) and int(test_p) <= int(high):
                        return True

            return False

        if not x or not y:
            raise ValueError()

        # Ok if exact match
        if x.match(y) == 0:
            return 0

        dbg_msg = "No fuzzy match '%s (v6=%s)' '%s (v6=%s)'" % \
                   (x, x.v6, y, y.v6)

        # Direction must match
        if y.direction != "in":
            debug("(direction) " + dbg_msg + " (not incoming)")
            return 1

        # Protocols must match or y 'any'
        if x.protocol != y.protocol and y.protocol != "any":
            debug("(protocol) " + dbg_msg)
            return 1

        # Destination ports must match or y 'any'
        if y.dport != "any" and not _match_ports(x.dport, y.dport):
            debug("(dport) " + dbg_msg)
            return 1

        if y.interface_in == "":
	    # If destination interface is not specified, destination addresses
            # must match or x must be contained in y

            if x.interface_in == "" and x._is_anywhere(x.dst):
		# if x and y interfaces are not specified, and x.dst is
                # anywhere then ok
                pass
            elif x.dst != y.dst and '/' not in y.dst:
                debug("(dst) " + dbg_msg)
                return 1
            elif x.dst != y.dst and '/' in y.dst and x.v6 == y.v6 and \
               not ufw.util.in_network(x.dst, y.dst, x.v6):
                debug("(dst) " + dbg_msg + " ('%s' not in network '%s')" % \
                      (x.dst, y.dst))
                return 1
        else:
	    # If destination interface is specified, then:
            #  if specified, both interfaces must match or
            #  the IP of the interface must match the IP of y or
	    #  the IP of the interface must be contained in y
            if x.interface_in != "" and x.interface_in != y.interface_in:
                debug("(interface) " + dbg_msg + " (%s != %s)" % \
                      (x.interface_in, y.interface_in))
                return 1

            try:
                if_ip = ufw.util.get_ip_from_if(y.interface_in, x.v6)
            except IOError:
                debug("(interface) " + dbg_msg + " %s does not exist" % \
                      (y.interface_in))
                return 1
            except Exception:
                raise
            if y.dst != if_ip and '/' not in y.dst:
                debug("(interface) " + dbg_msg + " (%s != %s)" % \
                      (y.dst, if_ip))
                return 1
            elif y.dst != if_ip and '/' in y.dst and x.v6 == y.v6 and \
               not ufw.util.in_network(if_ip, y.dst, x.v6):
                debug("(interface) " + dbg_msg + \
                      " ('%s' not in network '%s')" % (if_ip, y.dst))
                return 1

        if x.v6 != y.v6:
            debug("(v6) " + dbg_msg + " (%s != %s)" % (x.dst, y.dst))
            return 1

        # if we made it here, it is a fuzzy match
        debug("(fuzzy match) '%s (v6=%s)' '%s (v6=%s)'" % (x, x.v6, y, y.v6))
        return -1

    def _is_anywhere(self, addr):
        '''Check if address is anywhere'''
        if addr == "::/0" or addr == "0.0.0.0/0":
            return True
        return False

    def get_app_tuple(self):
        '''Returns a tuple to identify an app rule. Tuple is:
             dapp dst sapp src
           or
             dport dst sapp src
           or
             dapp dst sport src

           All of these might have in_eth0 out_eth0 (or similar) if an
           interface is also defined.
        '''
        tupl = ""
        if self.dapp != "" or self.sapp != "":
            tupl = "%s %s %s %s" % (self.dapp, self.dst, self.sapp, self.src)
            if self.dapp == "":
                tupl = "%s %s %s %s" % (self.dport, self.dst, self.sapp, \
                                         self.src)
            if self.sapp == "":
                tupl = "%s %s %s %s" % (self.dapp, self.dst, self.sport, \
                                         self.src)

            # add interfaces to the end, if they exist
            if self.interface_in != "":
                tupl += " in_%s" % (self.interface_in)
            if self.interface_out != "":
                tupl += " out_%s" % (self.interface_out)

        return tupl