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  • Committer: Teddy Hogeborn
  • Date: 2008-08-04 21:25:55 UTC
  • Revision ID: teddy@fukt.bsnet.se-20080804212555-rm7xxjze65f8avy3
* server.py: Cosmetic changes.

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#!/usr/bin/python
 
2
# -*- mode: python; coding: utf-8 -*-
 
3
 
4
# Mandos server - give out binary blobs to connecting clients.
 
5
 
6
# This program is partly derived from an example program for an Avahi
 
7
# service publisher, downloaded from
 
8
# <http://avahi.org/wiki/PythonPublishExample>.  This includes the
 
9
# following functions: "AvahiService.add", "AvahiService.remove",
 
10
# "server_state_changed", "entry_group_state_changed", and some lines
 
11
# in "main".
 
12
 
13
# Everything else is
 
14
# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
 
15
 
16
# This program is free software: you can redistribute it and/or modify
 
17
# it under the terms of the GNU General Public License as published by
 
18
# the Free Software Foundation, either version 3 of the License, or
 
19
# (at your option) any later version.
 
20
#
 
21
#     This program is distributed in the hope that it will be useful,
 
22
#     but WITHOUT ANY WARRANTY; without even the implied warranty of
 
23
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
24
#     GNU General Public License for more details.
 
25
 
26
# You should have received a copy of the GNU General Public License
 
27
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
28
 
29
# Contact the authors at <mandos@fukt.bsnet.se>.
 
30
 
31
 
 
32
from __future__ import division
2
33
 
3
34
import SocketServer
4
35
import socket
9
40
import gnutls.crypto
10
41
import gnutls.connection
11
42
import gnutls.errors
 
43
import gnutls.library.functions
 
44
import gnutls.library.constants
 
45
import gnutls.library.types
12
46
import ConfigParser
13
47
import sys
14
48
import re
15
49
import os
16
50
import signal
 
51
from sets import Set
 
52
import subprocess
 
53
import atexit
 
54
import stat
 
55
import logging
 
56
import logging.handlers
 
57
 
 
58
import dbus
 
59
import gobject
 
60
import avahi
 
61
from dbus.mainloop.glib import DBusGMainLoop
 
62
import ctypes
 
63
 
 
64
# Brief description of the operation of this program:
 
65
 
66
# This server announces itself as a Zeroconf service.  Connecting
 
67
# clients use the TLS protocol, with the unusual quirk that this
 
68
# server program acts as a TLS "client" while a connecting client acts
 
69
# as a TLS "server".  The client (acting as a TLS "server") must
 
70
# supply an OpenPGP certificate, and the fingerprint of this
 
71
# certificate is used by this server to look up (in a list read from a
 
72
# file at start time) which binary blob to give the client.  No other
 
73
# authentication or authorization is done by this server.
 
74
 
 
75
 
 
76
logger = logging.Logger('mandos')
 
77
syslogger = logging.handlers.SysLogHandler\
 
78
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON)
 
79
syslogger.setFormatter(logging.Formatter\
 
80
                        ('%(levelname)s: %(message)s'))
 
81
logger.addHandler(syslogger)
 
82
del syslogger
 
83
 
 
84
 
 
85
class AvahiError(Exception):
 
86
    def __init__(self, value):
 
87
        self.value = value
 
88
    def __str__(self):
 
89
        return repr(self.value)
 
90
 
 
91
class AvahiServiceError(AvahiError):
 
92
    pass
 
93
 
 
94
class AvahiGroupError(AvahiError):
 
95
    pass
 
96
 
 
97
 
 
98
class AvahiService(object):
 
99
    """An Avahi (Zeroconf) service.
 
100
    Attributes:
 
101
    interface: integer; avahi.IF_UNSPEC or an interface index.
 
102
               Used to optionally bind to the specified interface.
 
103
    name: string; Example: 'Mandos'
 
104
    type: string; Example: '_mandos._tcp'.
 
105
                  See <http://www.dns-sd.org/ServiceTypes.html>
 
106
    port: integer; what port to announce
 
107
    TXT: list of strings; TXT record for the service
 
108
    domain: string; Domain to publish on, default to .local if empty.
 
109
    host: string; Host to publish records for, default is localhost
 
110
    max_renames: integer; maximum number of renames
 
111
    rename_count: integer; counter so we only rename after collisions
 
112
                  a sensible number of times
 
113
    """
 
114
    def __init__(self, interface = avahi.IF_UNSPEC, name = None,
 
115
                 type = None, port = None, TXT = None, domain = "",
 
116
                 host = "", max_renames = 12):
 
117
        self.interface = interface
 
118
        self.name = name
 
119
        self.type = type
 
120
        self.port = port
 
121
        if TXT is None:
 
122
            self.TXT = []
 
123
        else:
 
124
            self.TXT = TXT
 
125
        self.domain = domain
 
126
        self.host = host
 
127
        self.rename_count = 0
 
128
    def rename(self):
 
129
        """Derived from the Avahi example code"""
 
130
        if self.rename_count >= self.max_renames:
 
131
            logger.critical(u"No suitable service name found after %i"
 
132
                            u" retries, exiting.", rename_count)
 
133
            raise AvahiServiceError("Too many renames")
 
134
        name = server.GetAlternativeServiceName(name)
 
135
        logger.error(u"Changing name to %r ...", name)
 
136
        self.remove()
 
137
        self.add()
 
138
        self.rename_count += 1
 
139
    def remove(self):
 
140
        """Derived from the Avahi example code"""
 
141
        if group is not None:
 
142
            group.Reset()
 
143
    def add(self):
 
144
        """Derived from the Avahi example code"""
 
145
        global group
 
146
        if group is None:
 
147
            group = dbus.Interface\
 
148
                    (bus.get_object(avahi.DBUS_NAME,
 
149
                                    server.EntryGroupNew()),
 
150
                     avahi.DBUS_INTERFACE_ENTRY_GROUP)
 
151
            group.connect_to_signal('StateChanged',
 
152
                                    entry_group_state_changed)
 
153
        logger.debug(u"Adding service '%s' of type '%s' ...",
 
154
                     service.name, service.type)
 
155
        group.AddService(
 
156
                self.interface,         # interface
 
157
                avahi.PROTO_INET6,      # protocol
 
158
                dbus.UInt32(0),         # flags
 
159
                self.name, self.type,
 
160
                self.domain, self.host,
 
161
                dbus.UInt16(self.port),
 
162
                avahi.string_array_to_txt_array(self.TXT))
 
163
        group.Commit()
 
164
 
 
165
# From the Avahi example code:
 
166
group = None                            # our entry group
 
167
# End of Avahi example code
 
168
 
17
169
 
18
170
class Client(object):
19
 
    def __init__(self, name=None, options=None, dn=None,
20
 
                 password=None, passfile=None, fqdn=None,
21
 
                 timeout=None, interval=-1):
 
171
    """A representation of a client host served by this server.
 
172
    Attributes:
 
173
    name:      string; from the config file, used in log messages
 
174
    fingerprint: string (40 or 32 hexadecimal digits); used to
 
175
                 uniquely identify the client
 
176
    secret:    bytestring; sent verbatim (over TLS) to client
 
177
    fqdn:      string (FQDN); available for use by the checker command
 
178
    created:   datetime.datetime(); object creation, not client host
 
179
    last_checked_ok: datetime.datetime() or None if not yet checked OK
 
180
    timeout:   datetime.timedelta(); How long from last_checked_ok
 
181
                                     until this client is invalid
 
182
    interval:  datetime.timedelta(); How often to start a new checker
 
183
    stop_hook: If set, called by stop() as stop_hook(self)
 
184
    checker:   subprocess.Popen(); a running checker process used
 
185
                                   to see if the client lives.
 
186
                                   'None' if no process is running.
 
187
    checker_initiator_tag: a gobject event source tag, or None
 
188
    stop_initiator_tag:    - '' -
 
189
    checker_callback_tag:  - '' -
 
190
    checker_command: string; External command which is run to check if
 
191
                     client lives.  %() expansions are done at
 
192
                     runtime with vars(self) as dict, so that for
 
193
                     instance %(name)s can be used in the command.
 
194
    Private attibutes:
 
195
    _timeout: Real variable for 'timeout'
 
196
    _interval: Real variable for 'interval'
 
197
    _timeout_milliseconds: Used when calling gobject.timeout_add()
 
198
    _interval_milliseconds: - '' -
 
199
    """
 
200
    def _set_timeout(self, timeout):
 
201
        "Setter function for 'timeout' attribute"
 
202
        self._timeout = timeout
 
203
        self._timeout_milliseconds = ((self.timeout.days
 
204
                                       * 24 * 60 * 60 * 1000)
 
205
                                      + (self.timeout.seconds * 1000)
 
206
                                      + (self.timeout.microseconds
 
207
                                         // 1000))
 
208
    timeout = property(lambda self: self._timeout,
 
209
                       _set_timeout)
 
210
    del _set_timeout
 
211
    def _set_interval(self, interval):
 
212
        "Setter function for 'interval' attribute"
 
213
        self._interval = interval
 
214
        self._interval_milliseconds = ((self.interval.days
 
215
                                        * 24 * 60 * 60 * 1000)
 
216
                                       + (self.interval.seconds
 
217
                                          * 1000)
 
218
                                       + (self.interval.microseconds
 
219
                                          // 1000))
 
220
    interval = property(lambda self: self._interval,
 
221
                        _set_interval)
 
222
    del _set_interval
 
223
    def __init__(self, name = None, stop_hook=None, config={}):
 
224
        """Note: the 'checker' key in 'config' sets the
 
225
        'checker_command' attribute and *not* the 'checker'
 
226
        attribute."""
22
227
        self.name = name
23
 
        self.dn = dn
24
 
        if password:
25
 
            self.password = password
26
 
        elif passfile:
27
 
            self.password = open(passfile).readall()
 
228
        logger.debug(u"Creating client %r", self.name)
 
229
        # Uppercase and remove spaces from fingerprint for later
 
230
        # comparison purposes with return value from the fingerprint()
 
231
        # function
 
232
        self.fingerprint = config["fingerprint"].upper()\
 
233
                           .replace(u" ", u"")
 
234
        logger.debug(u"  Fingerprint: %s", self.fingerprint)
 
235
        if "secret" in config:
 
236
            self.secret = config["secret"].decode(u"base64")
 
237
        elif "secfile" in config:
 
238
            sf = open(config["secfile"])
 
239
            self.secret = sf.read()
 
240
            sf.close()
28
241
        else:
29
 
            print "No Password or Passfile in client config file"
30
 
            # raise RuntimeError XXX
31
 
            self.password = "gazonk"
32
 
        self.fqdn = fqdn                # string
 
242
            raise TypeError(u"No secret or secfile for client %s"
 
243
                            % self.name)
 
244
        self.fqdn = config.get("fqdn", "")
33
245
        self.created = datetime.datetime.now()
34
 
        self.last_seen = None           # datetime.datetime()
35
 
        if timeout is None:
36
 
            timeout = options.timeout
37
 
        self.timeout = timeout          # datetime.timedelta()
38
 
        if interval == -1:
39
 
            interval = options.interval
40
 
        self.interval = interval        # datetime.timedelta()
41
 
        self.next_check = datetime.datetime.now() # datetime.datetime()
42
 
        self.checker = None             # or a subprocess.Popen()
43
 
    def check_action(self, now=None):
44
 
        """The checker said something and might have completed.
45
 
        Check if is has, and take appropriate actions."""
46
 
        if self.checker.poll() is None:
47
 
            # False alarm, no result yet
48
 
            #self.checker.read()
49
 
            return
50
 
        if now is None:
51
 
            now = datetime.datetime.now()
52
 
        if self.checker.returncode == 0:
53
 
            self.last_seen = now
54
 
        while self.next_check <= now:
55
 
            self.next_check += self.interval
56
 
    handle_request = check_action
 
246
        self.last_checked_ok = None
 
247
        self.timeout = string_to_delta(config["timeout"])
 
248
        self.interval = string_to_delta(config["interval"])
 
249
        self.stop_hook = stop_hook
 
250
        self.checker = None
 
251
        self.checker_initiator_tag = None
 
252
        self.stop_initiator_tag = None
 
253
        self.checker_callback_tag = None
 
254
        self.check_command = config["checker"]
 
255
    def start(self):
 
256
        """Start this client's checker and timeout hooks"""
 
257
        # Schedule a new checker to be started an 'interval' from now,
 
258
        # and every interval from then on.
 
259
        self.checker_initiator_tag = gobject.timeout_add\
 
260
                                     (self._interval_milliseconds,
 
261
                                      self.start_checker)
 
262
        # Also start a new checker *right now*.
 
263
        self.start_checker()
 
264
        # Schedule a stop() when 'timeout' has passed
 
265
        self.stop_initiator_tag = gobject.timeout_add\
 
266
                                  (self._timeout_milliseconds,
 
267
                                   self.stop)
 
268
    def stop(self):
 
269
        """Stop this client.
 
270
        The possibility that a client might be restarted is left open,
 
271
        but not currently used."""
 
272
        # If this client doesn't have a secret, it is already stopped.
 
273
        if self.secret:
 
274
            logger.info(u"Stopping client %s", self.name)
 
275
            self.secret = None
 
276
        else:
 
277
            return False
 
278
        if getattr(self, "stop_initiator_tag", False):
 
279
            gobject.source_remove(self.stop_initiator_tag)
 
280
            self.stop_initiator_tag = None
 
281
        if getattr(self, "checker_initiator_tag", False):
 
282
            gobject.source_remove(self.checker_initiator_tag)
 
283
            self.checker_initiator_tag = None
 
284
        self.stop_checker()
 
285
        if self.stop_hook:
 
286
            self.stop_hook(self)
 
287
        # Do not run this again if called by a gobject.timeout_add
 
288
        return False
 
289
    def __del__(self):
 
290
        self.stop_hook = None
 
291
        self.stop()
 
292
    def checker_callback(self, pid, condition):
 
293
        """The checker has completed, so take appropriate actions."""
 
294
        now = datetime.datetime.now()
 
295
        self.checker_callback_tag = None
 
296
        self.checker = None
 
297
        if os.WIFEXITED(condition) \
 
298
               and (os.WEXITSTATUS(condition) == 0):
 
299
            logger.info(u"Checker for %(name)s succeeded",
 
300
                        vars(self))
 
301
            self.last_checked_ok = now
 
302
            gobject.source_remove(self.stop_initiator_tag)
 
303
            self.stop_initiator_tag = gobject.timeout_add\
 
304
                                      (self._timeout_milliseconds,
 
305
                                       self.stop)
 
306
        elif not os.WIFEXITED(condition):
 
307
            logger.warning(u"Checker for %(name)s crashed?",
 
308
                           vars(self))
 
309
        else:
 
310
            logger.info(u"Checker for %(name)s failed",
 
311
                        vars(self))
57
312
    def start_checker(self):
58
 
        self.stop_checker()
59
 
        try:
60
 
            self.checker = subprocess.Popen("sleep 1; fping -q -- %s"
61
 
                                            % re.escape(self.fqdn),
62
 
                                            stdout=subprocess.PIPE,
63
 
                                            close_fds=True,
64
 
                                            shell=True, cwd="/")
65
 
        except subprocess.OSError, e:
66
 
            print "Failed to start subprocess:", e
 
313
        """Start a new checker subprocess if one is not running.
 
314
        If a checker already exists, leave it running and do
 
315
        nothing."""
 
316
        # The reason for not killing a running checker is that if we
 
317
        # did that, then if a checker (for some reason) started
 
318
        # running slowly and taking more than 'interval' time, the
 
319
        # client would inevitably timeout, since no checker would get
 
320
        # a chance to run to completion.  If we instead leave running
 
321
        # checkers alone, the checker would have to take more time
 
322
        # than 'timeout' for the client to be declared invalid, which
 
323
        # is as it should be.
 
324
        if self.checker is None:
 
325
            try:
 
326
                # In case check_command has exactly one % operator
 
327
                command = self.check_command % self.fqdn
 
328
            except TypeError:
 
329
                # Escape attributes for the shell
 
330
                escaped_attrs = dict((key, re.escape(str(val)))
 
331
                                     for key, val in
 
332
                                     vars(self).iteritems())
 
333
                try:
 
334
                    command = self.check_command % escaped_attrs
 
335
                except TypeError, error:
 
336
                    logger.error(u'Could not format string "%s":'
 
337
                                 u' %s', self.check_command, error)
 
338
                    return True # Try again later
 
339
            try:
 
340
                logger.info(u"Starting checker %r for %s",
 
341
                            command, self.name)
 
342
                self.checker = subprocess.Popen(command,
 
343
                                                close_fds=True,
 
344
                                                shell=True, cwd="/")
 
345
                self.checker_callback_tag = gobject.child_watch_add\
 
346
                                            (self.checker.pid,
 
347
                                             self.checker_callback)
 
348
            except subprocess.OSError, error:
 
349
                logger.error(u"Failed to start subprocess: %s",
 
350
                             error)
 
351
        # Re-run this periodically if run by gobject.timeout_add
 
352
        return True
67
353
    def stop_checker(self):
68
 
        if self.checker is None:
 
354
        """Force the checker process, if any, to stop."""
 
355
        if self.checker_callback_tag:
 
356
            gobject.source_remove(self.checker_callback_tag)
 
357
            self.checker_callback_tag = None
 
358
        if getattr(self, "checker", None) is None:
69
359
            return
70
 
        os.kill(self.checker.pid, signal.SIGTERM)
71
 
        if self.checker.poll() is None:
72
 
            os.kill(self.checker.pid, signal.SIGKILL)
 
360
        logger.debug("Stopping checker for %(name)s", vars(self))
 
361
        try:
 
362
            os.kill(self.checker.pid, signal.SIGTERM)
 
363
            #os.sleep(0.5)
 
364
            #if self.checker.poll() is None:
 
365
            #    os.kill(self.checker.pid, signal.SIGKILL)
 
366
        except OSError, error:
 
367
            if error.errno != errno.ESRCH: # No such process
 
368
                raise
73
369
        self.checker = None
74
 
    __del__ = stop_checker
75
 
    def fileno(self):
76
 
        if self.checker is None:
77
 
            return None
78
 
        return self.checker.stdout.fileno()
79
 
    def next_stop(self):
80
 
        """The time when something must be done about this client"""
81
 
        return min(self.last_seen + self.timeout, self.next_check)
82
 
    def still_valid(self, now=None):
83
 
        """Has this client's timeout not passed?"""
84
 
        if now is None:
85
 
            now = datetime.datetime.now()
86
 
        return now < (self.last_seen + timeout)
87
 
    def it_is_time_to_check(self, now=None):
88
 
        if now is None:
89
 
            now = datetime.datetime.now()
90
 
        return self.next_check <= now
91
 
 
92
 
 
93
 
class server_metaclass(type):
94
 
    "Common behavior for the UDP and TCP server classes"
95
 
    def __new__(cls, name, bases, attrs):
96
 
        attrs["address_family"] = socket.AF_INET6
97
 
        attrs["allow_reuse_address"] = True
98
 
        def server_bind(self):
99
 
            if self.options.interface:
100
 
                if not hasattr(socket, "SO_BINDTODEVICE"):
101
 
                    # From /usr/include/asm-i486/socket.h
102
 
                    socket.SO_BINDTODEVICE = 25
103
 
                try:
104
 
                    self.socket.setsockopt(socket.SOL_SOCKET,
105
 
                                           socket.SO_BINDTODEVICE,
106
 
                                           self.options.interface)
107
 
                except socket.error, error:
108
 
                    if error[0] == errno.EPERM:
109
 
                        print "Warning: No permission to bind to interface", \
110
 
                              self.options.interface
111
 
                    else:
112
 
                        raise error
113
 
            return super(type(self), self).server_bind()
114
 
        attrs["server_bind"] = server_bind
115
 
        def init(self, *args, **kwargs):
116
 
            if "options" in kwargs:
117
 
                self.options = kwargs["options"]
118
 
                del kwargs["options"]
119
 
            if "clients" in kwargs:
120
 
                self.clients = kwargs["clients"]
121
 
                del kwargs["clients"]
122
 
            if "credentials" in kwargs:
123
 
                self.credentials = kwargs["credentials"]
124
 
                del kwargs["credentials"]
125
 
            return super(type(self), self).__init__(*args, **kwargs)
126
 
        attrs["__init__"] = init
127
 
        return type.__new__(cls, name, bases, attrs)
128
 
 
129
 
 
130
 
class udp_handler(SocketServer.DatagramRequestHandler, object):
131
 
    def handle(self):
132
 
        self.wfile.write("Polo")
133
 
        print "UDP request answered"
134
 
 
135
 
 
136
 
class IPv6_UDPServer(SocketServer.UDPServer, object):
137
 
    __metaclass__ = server_metaclass
138
 
    def verify_request(self, request, client_address):
139
 
        print "UDP request came"
140
 
        return request[0] == "Marco"
 
370
    def still_valid(self):
 
371
        """Has the timeout not yet passed for this client?"""
 
372
        now = datetime.datetime.now()
 
373
        if self.last_checked_ok is None:
 
374
            return now < (self.created + self.timeout)
 
375
        else:
 
376
            return now < (self.last_checked_ok + self.timeout)
 
377
 
 
378
 
 
379
def peer_certificate(session):
 
380
    "Return the peer's OpenPGP certificate as a bytestring"
 
381
    # If not an OpenPGP certificate...
 
382
    if gnutls.library.functions.gnutls_certificate_type_get\
 
383
            (session._c_object) \
 
384
           != gnutls.library.constants.GNUTLS_CRT_OPENPGP:
 
385
        # ...do the normal thing
 
386
        return session.peer_certificate
 
387
    list_size = ctypes.c_uint()
 
388
    cert_list = gnutls.library.functions.gnutls_certificate_get_peers\
 
389
        (session._c_object, ctypes.byref(list_size))
 
390
    if list_size.value == 0:
 
391
        return None
 
392
    cert = cert_list[0]
 
393
    return ctypes.string_at(cert.data, cert.size)
 
394
 
 
395
 
 
396
def fingerprint(openpgp):
 
397
    "Convert an OpenPGP bytestring to a hexdigit fingerprint string"
 
398
    # New GnuTLS "datum" with the OpenPGP public key
 
399
    datum = gnutls.library.types.gnutls_datum_t\
 
400
        (ctypes.cast(ctypes.c_char_p(openpgp),
 
401
                     ctypes.POINTER(ctypes.c_ubyte)),
 
402
         ctypes.c_uint(len(openpgp)))
 
403
    # New empty GnuTLS certificate
 
404
    crt = gnutls.library.types.gnutls_openpgp_crt_t()
 
405
    gnutls.library.functions.gnutls_openpgp_crt_init\
 
406
        (ctypes.byref(crt))
 
407
    # Import the OpenPGP public key into the certificate
 
408
    gnutls.library.functions.gnutls_openpgp_crt_import\
 
409
                    (crt, ctypes.byref(datum),
 
410
                     gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
 
411
    # New buffer for the fingerprint
 
412
    buffer = ctypes.create_string_buffer(20)
 
413
    buffer_length = ctypes.c_size_t()
 
414
    # Get the fingerprint from the certificate into the buffer
 
415
    gnutls.library.functions.gnutls_openpgp_crt_get_fingerprint\
 
416
        (crt, ctypes.byref(buffer), ctypes.byref(buffer_length))
 
417
    # Deinit the certificate
 
418
    gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
 
419
    # Convert the buffer to a Python bytestring
 
420
    fpr = ctypes.string_at(buffer, buffer_length.value)
 
421
    # Convert the bytestring to hexadecimal notation
 
422
    hex_fpr = u''.join(u"%02X" % ord(char) for char in fpr)
 
423
    return hex_fpr
141
424
 
142
425
 
143
426
class tcp_handler(SocketServer.BaseRequestHandler, object):
 
427
    """A TCP request handler class.
 
428
    Instantiated by IPv6_TCPServer for each request to handle it.
 
429
    Note: This will run in its own forked process."""
 
430
    
144
431
    def handle(self):
145
 
        print "TCP request came"
146
 
        print "Request:", self.request
147
 
        print "Client Address:", self.client_address
148
 
        print "Server:", self.server
149
 
        session = gnutls.connection.ServerSession(self.request,
150
 
                                                  self.server.credentials)
151
 
        session.handshake()
152
 
        if session.peer_certificate:
153
 
            print "DN:", session.peer_certificate.subject
154
 
        try:
155
 
            session.verify_peer()
156
 
        except gnutls.errors.CertificateError, error:
157
 
            print "Verify failed", error
158
 
            session.bye()
159
 
            return
160
 
        try:
161
 
            session.send(dict((client.dn, client.password)
162
 
                              for client in self.server.clients)
163
 
                         [session.peer_certificate.subject])
164
 
        except KeyError:
165
 
            session.send("gazonk")
166
 
            # Log maybe? XXX
 
432
        logger.info(u"TCP connection from: %s",
 
433
                     unicode(self.client_address))
 
434
        session = gnutls.connection.ClientSession\
 
435
                  (self.request, gnutls.connection.X509Credentials())
 
436
        
 
437
        line = self.request.makefile().readline()
 
438
        logger.debug(u"Protocol version: %r", line)
 
439
        try:
 
440
            if int(line.strip().split()[0]) > 1:
 
441
                raise RuntimeError
 
442
        except (ValueError, IndexError, RuntimeError), error:
 
443
            logger.error(u"Unknown protocol version: %s", error)
 
444
            return
 
445
        
 
446
        # Note: gnutls.connection.X509Credentials is really a generic
 
447
        # GnuTLS certificate credentials object so long as no X.509
 
448
        # keys are added to it.  Therefore, we can use it here despite
 
449
        # using OpenPGP certificates.
 
450
        
 
451
        #priority = ':'.join(("NONE", "+VERS-TLS1.1", "+AES-256-CBC",
 
452
        #                "+SHA1", "+COMP-NULL", "+CTYPE-OPENPGP",
 
453
        #                "+DHE-DSS"))
 
454
        priority = "NORMAL"             # Fallback default, since this
 
455
                                        # MUST be set.
 
456
        if self.server.settings["priority"]:
 
457
            priority = self.server.settings["priority"]
 
458
        gnutls.library.functions.gnutls_priority_set_direct\
 
459
            (session._c_object, priority, None);
 
460
        
 
461
        try:
 
462
            session.handshake()
 
463
        except gnutls.errors.GNUTLSError, error:
 
464
            logger.warning(u"Handshake failed: %s", error)
 
465
            # Do not run session.bye() here: the session is not
 
466
            # established.  Just abandon the request.
 
467
            return
 
468
        try:
 
469
            fpr = fingerprint(peer_certificate(session))
 
470
        except (TypeError, gnutls.errors.GNUTLSError), error:
 
471
            logger.warning(u"Bad certificate: %s", error)
 
472
            session.bye()
 
473
            return
 
474
        logger.debug(u"Fingerprint: %s", fpr)
 
475
        client = None
 
476
        for c in self.server.clients:
 
477
            if c.fingerprint == fpr:
 
478
                client = c
 
479
                break
 
480
        if not client:
 
481
            logger.warning(u"Client not found for fingerprint: %s",
 
482
                           fpr)
 
483
            session.bye()
 
484
            return
 
485
        # Have to check if client.still_valid(), since it is possible
 
486
        # that the client timed out while establishing the GnuTLS
 
487
        # session.
 
488
        if not client.still_valid():
 
489
            logger.warning(u"Client %(name)s is invalid",
 
490
                           vars(client))
 
491
            session.bye()
 
492
            return
 
493
        sent_size = 0
 
494
        while sent_size < len(client.secret):
 
495
            sent = session.send(client.secret[sent_size:])
 
496
            logger.debug(u"Sent: %d, remaining: %d",
 
497
                         sent, len(client.secret)
 
498
                         - (sent_size + sent))
 
499
            sent_size += sent
167
500
        session.bye()
168
501
 
169
502
 
170
503
class IPv6_TCPServer(SocketServer.ForkingTCPServer, object):
171
 
    __metaclass__ = server_metaclass
172
 
    request_queue_size = 1024
173
 
 
174
 
 
175
 
in6addr_any = "::"
 
504
    """IPv6 TCP server.  Accepts 'None' as address and/or port.
 
505
    Attributes:
 
506
        settings:       Server settings
 
507
        clients:        Set() of Client objects
 
508
    """
 
509
    address_family = socket.AF_INET6
 
510
    def __init__(self, *args, **kwargs):
 
511
        if "settings" in kwargs:
 
512
            self.settings = kwargs["settings"]
 
513
            del kwargs["settings"]
 
514
        if "clients" in kwargs:
 
515
            self.clients = kwargs["clients"]
 
516
            del kwargs["clients"]
 
517
        return super(type(self), self).__init__(*args, **kwargs)
 
518
    def server_bind(self):
 
519
        """This overrides the normal server_bind() function
 
520
        to bind to an interface if one was specified, and also NOT to
 
521
        bind to an address or port if they were not specified."""
 
522
        if self.settings["interface"]:
 
523
            # 25 is from /usr/include/asm-i486/socket.h
 
524
            SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
 
525
            try:
 
526
                self.socket.setsockopt(socket.SOL_SOCKET,
 
527
                                       SO_BINDTODEVICE,
 
528
                                       self.settings["interface"])
 
529
            except socket.error, error:
 
530
                if error[0] == errno.EPERM:
 
531
                    logger.error(u"No permission to"
 
532
                                 u" bind to interface %s",
 
533
                                 self.settings["interface"])
 
534
                else:
 
535
                    raise error
 
536
        # Only bind(2) the socket if we really need to.
 
537
        if self.server_address[0] or self.server_address[1]:
 
538
            if not self.server_address[0]:
 
539
                in6addr_any = "::"
 
540
                self.server_address = (in6addr_any,
 
541
                                       self.server_address[1])
 
542
            elif self.server_address[1] is None:
 
543
                self.server_address = (self.server_address[0],
 
544
                                       0)
 
545
            return super(type(self), self).server_bind()
 
546
 
176
547
 
177
548
def string_to_delta(interval):
178
549
    """Parse a string and return a datetime.timedelta
208
579
    return delta
209
580
 
210
581
 
 
582
def server_state_changed(state):
 
583
    """Derived from the Avahi example code"""
 
584
    if state == avahi.SERVER_COLLISION:
 
585
        logger.error(u"Server name collision")
 
586
        service.remove()
 
587
    elif state == avahi.SERVER_RUNNING:
 
588
        service.add()
 
589
 
 
590
 
 
591
def entry_group_state_changed(state, error):
 
592
    """Derived from the Avahi example code"""
 
593
    logger.debug(u"state change: %i", state)
 
594
    
 
595
    if state == avahi.ENTRY_GROUP_ESTABLISHED:
 
596
        logger.debug(u"Service established.")
 
597
    elif state == avahi.ENTRY_GROUP_COLLISION:
 
598
        logger.warning(u"Service name collision.")
 
599
        service.rename()
 
600
    elif state == avahi.ENTRY_GROUP_FAILURE:
 
601
        logger.critical(u"Error in group state changed %s",
 
602
                        unicode(error))
 
603
        raise AvahiGroupError("State changed: %s", str(error))
 
604
 
 
605
def if_nametoindex(interface):
 
606
    """Call the C function if_nametoindex(), or equivalent"""
 
607
    global if_nametoindex
 
608
    try:
 
609
        if "ctypes.util" not in sys.modules:
 
610
            import ctypes.util
 
611
        if_nametoindex = ctypes.cdll.LoadLibrary\
 
612
            (ctypes.util.find_library("c")).if_nametoindex
 
613
    except (OSError, AttributeError):
 
614
        if "struct" not in sys.modules:
 
615
            import struct
 
616
        if "fcntl" not in sys.modules:
 
617
            import fcntl
 
618
        def if_nametoindex(interface):
 
619
            "Get an interface index the hard way, i.e. using fcntl()"
 
620
            SIOCGIFINDEX = 0x8933  # From /usr/include/linux/sockios.h
 
621
            s = socket.socket()
 
622
            ifreq = fcntl.ioctl(s, SIOCGIFINDEX,
 
623
                                struct.pack("16s16x", interface))
 
624
            s.close()
 
625
            interface_index = struct.unpack("I", ifreq[16:20])[0]
 
626
            return interface_index
 
627
    return if_nametoindex(interface)
 
628
 
 
629
 
 
630
def daemon(nochdir, noclose):
 
631
    """See daemon(3).  Standard BSD Unix function.
 
632
    This should really exist as os.daemon, but it doesn't (yet)."""
 
633
    if os.fork():
 
634
        sys.exit()
 
635
    os.setsid()
 
636
    if not nochdir:
 
637
        os.chdir("/")
 
638
    if not noclose:
 
639
        # Close all standard open file descriptors
 
640
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
 
641
        if not stat.S_ISCHR(os.fstat(null).st_mode):
 
642
            raise OSError(errno.ENODEV,
 
643
                          "/dev/null not a character device")
 
644
        os.dup2(null, sys.stdin.fileno())
 
645
        os.dup2(null, sys.stdout.fileno())
 
646
        os.dup2(null, sys.stderr.fileno())
 
647
        if null > 2:
 
648
            os.close(null)
 
649
 
 
650
 
211
651
def main():
 
652
    global main_loop_started
 
653
    main_loop_started = False
 
654
    
212
655
    parser = OptionParser()
213
656
    parser.add_option("-i", "--interface", type="string",
214
 
                      default="eth0", metavar="IF",
215
 
                      help="Interface to bind to")
216
 
    parser.add_option("--cert", type="string", default="cert.pem",
217
 
                      metavar="FILE",
218
 
                      help="Public key certificate to use")
219
 
    parser.add_option("--key", type="string", default="key.pem",
220
 
                      metavar="FILE",
221
 
                      help="Private key to use")
222
 
    parser.add_option("--ca", type="string", default="ca.pem",
223
 
                      metavar="FILE",
224
 
                      help="Certificate Authority certificate to use")
225
 
    parser.add_option("--crl", type="string", default="crl.pem",
226
 
                      metavar="FILE",
227
 
                      help="Certificate Revokation List to use")
228
 
    parser.add_option("-p", "--port", type="int", default=49001,
 
657
                      metavar="IF", help="Bind to interface IF")
 
658
    parser.add_option("-a", "--address", type="string",
 
659
                      help="Address to listen for requests on")
 
660
    parser.add_option("-p", "--port", type="int",
229
661
                      help="Port number to receive requests on")
230
 
    parser.add_option("--dh", type="int", metavar="BITS",
231
 
                      help="DH group to use")
232
 
    parser.add_option("-t", "--timeout", type="string", # Parsed later
233
 
                      default="15m",
234
 
                      help="Amount of downtime allowed for clients")
235
 
    parser.add_option("--interval", type="string", # Parsed later
236
 
                      default="5m",
237
 
                      help="How often to check that a client is up")
238
662
    parser.add_option("--check", action="store_true", default=False,
239
663
                      help="Run self-test")
 
664
    parser.add_option("--debug", action="store_true", default=False,
 
665
                      help="Debug mode; run in foreground and log to"
 
666
                      " terminal")
 
667
    parser.add_option("--priority", type="string", help="GnuTLS"
 
668
                      " priority string (see GnuTLS documentation)")
 
669
    parser.add_option("--servicename", type="string", metavar="NAME",
 
670
                      help="Zeroconf service name")
 
671
    parser.add_option("--configdir", type="string",
 
672
                      default="/etc/mandos", metavar="DIR",
 
673
                      help="Directory to search for configuration"
 
674
                      " files")
240
675
    (options, args) = parser.parse_args()
241
 
 
 
676
    
242
677
    if options.check:
243
678
        import doctest
244
679
        doctest.testmod()
245
680
        sys.exit()
246
681
    
247
 
    # Parse the time arguments
248
 
    try:
249
 
        options.timeout = string_to_delta(options.timeout)
250
 
    except ValueError:
251
 
        parser.error("option --timeout: Unparseable time")
252
 
    
253
 
    try:
254
 
        options.interval = string_to_delta(options.interval)
255
 
    except ValueError:
256
 
        parser.error("option --interval: Unparseable time")
257
 
    
258
 
    cert = gnutls.crypto.X509Certificate(open(options.cert).read())
259
 
    key = gnutls.crypto.X509PrivateKey(open(options.key).read())
260
 
    ca = gnutls.crypto.X509Certificate(open(options.ca).read())
261
 
    crl = gnutls.crypto.X509CRL(open(options.crl).read())
262
 
    cred = gnutls.connection.X509Credentials(cert, key, [ca], [crl])
263
 
    
264
 
    # Parse config file
265
 
    defaults = {}
266
 
    client_config_object = ConfigParser.SafeConfigParser(defaults)
267
 
    client_config_object.read("mandos-clients.conf")
268
 
    clients = [Client(name=section, options=options,
269
 
                      **(dict(client_config_object.items(section))))
270
 
               for section in client_config_object.sections()]
271
 
    
272
 
    udp_server = IPv6_UDPServer((in6addr_any, options.port),
273
 
                                udp_handler,
274
 
                                options=options)
275
 
    
276
 
    tcp_server = IPv6_TCPServer((in6addr_any, options.port),
 
682
    # Default values for config file for server-global settings
 
683
    server_defaults = { "interface": "",
 
684
                        "address": "",
 
685
                        "port": "",
 
686
                        "debug": "False",
 
687
                        "priority":
 
688
                        "SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP",
 
689
                        "servicename": "Mandos",
 
690
                        }
 
691
    
 
692
    # Parse config file for server-global settings
 
693
    server_config = ConfigParser.SafeConfigParser(server_defaults)
 
694
    del server_defaults
 
695
    server_config.read(os.path.join(options.configdir, "server.conf"))
 
696
    server_section = "server"
 
697
    # Convert the SafeConfigParser object to a dict
 
698
    server_settings = dict(server_config.items(server_section))
 
699
    # Use getboolean on the boolean config option
 
700
    server_settings["debug"] = server_config.getboolean\
 
701
                               (server_section, "debug")
 
702
    del server_config
 
703
    
 
704
    # Override the settings from the config file with command line
 
705
    # options, if set.
 
706
    for option in ("interface", "address", "port", "debug",
 
707
                   "priority", "servicename", "configdir"):
 
708
        value = getattr(options, option)
 
709
        if value is not None:
 
710
            server_settings[option] = value
 
711
    del options
 
712
    # Now we have our good server settings in "server_settings"
 
713
    
 
714
    # Parse config file with clients
 
715
    client_defaults = { "timeout": "1h",
 
716
                        "interval": "5m",
 
717
                        "checker": "fping -q -- %%(fqdn)s",
 
718
                        }
 
719
    client_config = ConfigParser.SafeConfigParser(client_defaults)
 
720
    client_config.read(os.path.join(server_settings["configdir"],
 
721
                                    "clients.conf"))
 
722
    
 
723
    global service
 
724
    service = AvahiService(name = server_settings["servicename"],
 
725
                           type = "_mandos._tcp", );
 
726
    if server_settings["interface"]:
 
727
        service.interface = if_nametoindex(server_settings["interface"])
 
728
    
 
729
    global main_loop
 
730
    global bus
 
731
    global server
 
732
    # From the Avahi example code
 
733
    DBusGMainLoop(set_as_default=True )
 
734
    main_loop = gobject.MainLoop()
 
735
    bus = dbus.SystemBus()
 
736
    server = dbus.Interface(
 
737
            bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
 
738
            avahi.DBUS_INTERFACE_SERVER )
 
739
    # End of Avahi example code
 
740
    
 
741
    debug = server_settings["debug"]
 
742
    
 
743
    if debug:
 
744
        console = logging.StreamHandler()
 
745
        # console.setLevel(logging.DEBUG)
 
746
        console.setFormatter(logging.Formatter\
 
747
                             ('%(levelname)s: %(message)s'))
 
748
        logger.addHandler(console)
 
749
        del console
 
750
    
 
751
    clients = Set()
 
752
    def remove_from_clients(client):
 
753
        clients.remove(client)
 
754
        if not clients:
 
755
            logger.critical(u"No clients left, exiting")
 
756
            sys.exit()
 
757
    
 
758
    clients.update(Set(Client(name = section,
 
759
                              stop_hook = remove_from_clients,
 
760
                              config
 
761
                              = dict(client_config.items(section)))
 
762
                       for section in client_config.sections()))
 
763
    
 
764
    if not debug:
 
765
        daemon(False, False)
 
766
    
 
767
    def cleanup():
 
768
        "Cleanup function; run on exit"
 
769
        global group
 
770
        # From the Avahi example code
 
771
        if not group is None:
 
772
            group.Free()
 
773
            group = None
 
774
        # End of Avahi example code
 
775
        
 
776
        while clients:
 
777
            client = clients.pop()
 
778
            client.stop_hook = None
 
779
            client.stop()
 
780
    
 
781
    atexit.register(cleanup)
 
782
    
 
783
    if not debug:
 
784
        signal.signal(signal.SIGINT, signal.SIG_IGN)
 
785
    signal.signal(signal.SIGHUP, lambda signum, frame: sys.exit())
 
786
    signal.signal(signal.SIGTERM, lambda signum, frame: sys.exit())
 
787
    
 
788
    for client in clients:
 
789
        client.start()
 
790
    
 
791
    tcp_server = IPv6_TCPServer((server_settings["address"],
 
792
                                 server_settings["port"]),
277
793
                                tcp_handler,
278
 
                                options=options,
279
 
                                clients=clients,
280
 
                                credentials=cred)
281
 
    
282
 
    while True:
 
794
                                settings=server_settings,
 
795
                                clients=clients)
 
796
    # Find out what port we got
 
797
    service.port = tcp_server.socket.getsockname()[1]
 
798
    logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
 
799
                u" scope_id %d" % tcp_server.socket.getsockname())
 
800
    
 
801
    #service.interface = tcp_server.socket.getsockname()[3]
 
802
    
 
803
    try:
 
804
        # From the Avahi example code
 
805
        server.connect_to_signal("StateChanged", server_state_changed)
283
806
        try:
284
 
            input, out, err = select.select((udp_server,
285
 
                                             tcp_server), (), ())
286
 
            if not input:
287
 
                pass
288
 
            else:
289
 
                for obj in input:
290
 
                    obj.handle_request()
291
 
        except KeyboardInterrupt:
292
 
            break
293
 
    
294
 
    # Cleanup here
295
 
    for client in clients:
296
 
        client.stop_checker()
297
 
 
298
 
 
299
 
if __name__ == "__main__":
 
807
            server_state_changed(server.GetState())
 
808
        except dbus.exceptions.DBusException, error:
 
809
            logger.critical(u"DBusException: %s", error)
 
810
            sys.exit(1)
 
811
        # End of Avahi example code
 
812
        
 
813
        gobject.io_add_watch(tcp_server.fileno(), gobject.IO_IN,
 
814
                             lambda *args, **kwargs:
 
815
                             tcp_server.handle_request\
 
816
                             (*args[2:], **kwargs) or True)
 
817
        
 
818
        logger.debug("Starting main loop")
 
819
        main_loop_started = True
 
820
        main_loop.run()
 
821
    except AvahiError, error:
 
822
        logger.critical(u"AvahiError: %s" + unicode(error))
 
823
        sys.exit(1)
 
824
    except KeyboardInterrupt:
 
825
        if debug:
 
826
            print
 
827
 
 
828
if __name__ == '__main__':
300
829
    main()
301