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mandos
1
1
#!/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
# methods "add" and "remove" in the "AvahiService" class, the
 
10
# "server_state_changed" and "entry_group_state_changed" functions,
 
11
# and some lines 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
 
28
# <http://www.gnu.org/licenses/>.
 
29
# 
 
30
# Contact the authors at <mandos@fukt.bsnet.se>.
 
31
# 
 
32
 
 
33
from __future__ import division
2
34
 
3
35
import SocketServer
4
36
import socket
9
41
import gnutls.crypto
10
42
import gnutls.connection
11
43
import gnutls.errors
 
44
import gnutls.library.functions
 
45
import gnutls.library.constants
 
46
import gnutls.library.types
12
47
import ConfigParser
13
48
import sys
14
49
import re
15
50
import os
16
51
import signal
 
52
from sets import Set
 
53
import subprocess
 
54
import atexit
 
55
import stat
 
56
import logging
 
57
import logging.handlers
 
58
 
 
59
import dbus
 
60
import gobject
 
61
import avahi
 
62
from dbus.mainloop.glib import DBusGMainLoop
 
63
import ctypes
 
64
 
 
65
version = "1.0"
 
66
 
 
67
logger = logging.Logger('mandos')
 
68
syslogger = logging.handlers.SysLogHandler\
 
69
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON,
 
70
             address = "/dev/log")
 
71
syslogger.setFormatter(logging.Formatter\
 
72
                        ('Mandos: %(levelname)s: %(message)s'))
 
73
logger.addHandler(syslogger)
 
74
 
 
75
console = logging.StreamHandler()
 
76
console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
 
77
                                       ' %(message)s'))
 
78
logger.addHandler(console)
 
79
 
 
80
class AvahiError(Exception):
 
81
    def __init__(self, value):
 
82
        self.value = value
 
83
    def __str__(self):
 
84
        return repr(self.value)
 
85
 
 
86
class AvahiServiceError(AvahiError):
 
87
    pass
 
88
 
 
89
class AvahiGroupError(AvahiError):
 
90
    pass
 
91
 
 
92
 
 
93
class AvahiService(object):
 
94
    """An Avahi (Zeroconf) service.
 
95
    Attributes:
 
96
    interface: integer; avahi.IF_UNSPEC or an interface index.
 
97
               Used to optionally bind to the specified interface.
 
98
    name: string; Example: 'Mandos'
 
99
    type: string; Example: '_mandos._tcp'.
 
100
                  See <http://www.dns-sd.org/ServiceTypes.html>
 
101
    port: integer; what port to announce
 
102
    TXT: list of strings; TXT record for the service
 
103
    domain: string; Domain to publish on, default to .local if empty.
 
104
    host: string; Host to publish records for, default is localhost
 
105
    max_renames: integer; maximum number of renames
 
106
    rename_count: integer; counter so we only rename after collisions
 
107
                  a sensible number of times
 
108
    """
 
109
    def __init__(self, interface = avahi.IF_UNSPEC, name = None,
 
110
                 type = None, port = None, TXT = None, domain = "",
 
111
                 host = "", max_renames = 32768):
 
112
        self.interface = interface
 
113
        self.name = name
 
114
        self.type = type
 
115
        self.port = port
 
116
        if TXT is None:
 
117
            self.TXT = []
 
118
        else:
 
119
            self.TXT = TXT
 
120
        self.domain = domain
 
121
        self.host = host
 
122
        self.rename_count = 0
 
123
        self.max_renames = max_renames
 
124
    def rename(self):
 
125
        """Derived from the Avahi example code"""
 
126
        if self.rename_count >= self.max_renames:
 
127
            logger.critical(u"No suitable Zeroconf service name found"
 
128
                            u" after %i retries, exiting.",
 
129
                            rename_count)
 
130
            raise AvahiServiceError("Too many renames")
 
131
        self.name = server.GetAlternativeServiceName(self.name)
 
132
        logger.info(u"Changing Zeroconf service name to %r ...",
 
133
                    str(self.name))
 
134
        syslogger.setFormatter(logging.Formatter\
 
135
                               ('Mandos (%s): %%(levelname)s:'
 
136
                               ' %%(message)s' % self.name))
 
137
        self.remove()
 
138
        self.add()
 
139
        self.rename_count += 1
 
140
    def remove(self):
 
141
        """Derived from the Avahi example code"""
 
142
        if group is not None:
 
143
            group.Reset()
 
144
    def add(self):
 
145
        """Derived from the Avahi example code"""
 
146
        global group
 
147
        if group is None:
 
148
            group = dbus.Interface\
 
149
                    (bus.get_object(avahi.DBUS_NAME,
 
150
                                    server.EntryGroupNew()),
 
151
                     avahi.DBUS_INTERFACE_ENTRY_GROUP)
 
152
            group.connect_to_signal('StateChanged',
 
153
                                    entry_group_state_changed)
 
154
        logger.debug(u"Adding Zeroconf service '%s' of type '%s' ...",
 
155
                     service.name, service.type)
 
156
        group.AddService(
 
157
                self.interface,         # interface
 
158
                avahi.PROTO_INET6,      # protocol
 
159
                dbus.UInt32(0),         # flags
 
160
                self.name, self.type,
 
161
                self.domain, self.host,
 
162
                dbus.UInt16(self.port),
 
163
                avahi.string_array_to_txt_array(self.TXT))
 
164
        group.Commit()
 
165
 
 
166
# From the Avahi example code:
 
167
group = None                            # our entry group
 
168
# End of Avahi example code
 
169
 
17
170
 
18
171
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):
 
172
    """A representation of a client host served by this server.
 
173
    Attributes:
 
174
    name:      string; from the config file, used in log messages
 
175
    fingerprint: string (40 or 32 hexadecimal digits); used to
 
176
                 uniquely identify the client
 
177
    secret:    bytestring; sent verbatim (over TLS) to client
 
178
    host:      string; available for use by the checker command
 
179
    created:   datetime.datetime(); object creation, not client host
 
180
    last_checked_ok: datetime.datetime() or None if not yet checked OK
 
181
    timeout:   datetime.timedelta(); How long from last_checked_ok
 
182
                                     until this client is invalid
 
183
    interval:  datetime.timedelta(); How often to start a new checker
 
184
    stop_hook: If set, called by stop() as stop_hook(self)
 
185
    checker:   subprocess.Popen(); a running checker process used
 
186
                                   to see if the client lives.
 
187
                                   'None' if no process is running.
 
188
    checker_initiator_tag: a gobject event source tag, or None
 
189
    stop_initiator_tag:    - '' -
 
190
    checker_callback_tag:  - '' -
 
191
    checker_command: string; External command which is run to check if
 
192
                     client lives.  %() expansions are done at
 
193
                     runtime with vars(self) as dict, so that for
 
194
                     instance %(name)s can be used in the command.
 
195
    Private attibutes:
 
196
    _timeout: Real variable for 'timeout'
 
197
    _interval: Real variable for 'interval'
 
198
    _timeout_milliseconds: Used when calling gobject.timeout_add()
 
199
    _interval_milliseconds: - '' -
 
200
    """
 
201
    def _set_timeout(self, timeout):
 
202
        "Setter function for 'timeout' attribute"
 
203
        self._timeout = timeout
 
204
        self._timeout_milliseconds = ((self.timeout.days
 
205
                                       * 24 * 60 * 60 * 1000)
 
206
                                      + (self.timeout.seconds * 1000)
 
207
                                      + (self.timeout.microseconds
 
208
                                         // 1000))
 
209
    timeout = property(lambda self: self._timeout,
 
210
                       _set_timeout)
 
211
    del _set_timeout
 
212
    def _set_interval(self, interval):
 
213
        "Setter function for 'interval' attribute"
 
214
        self._interval = interval
 
215
        self._interval_milliseconds = ((self.interval.days
 
216
                                        * 24 * 60 * 60 * 1000)
 
217
                                       + (self.interval.seconds
 
218
                                          * 1000)
 
219
                                       + (self.interval.microseconds
 
220
                                          // 1000))
 
221
    interval = property(lambda self: self._interval,
 
222
                        _set_interval)
 
223
    del _set_interval
 
224
    def __init__(self, name = None, stop_hook=None, config={}):
 
225
        """Note: the 'checker' key in 'config' sets the
 
226
        'checker_command' attribute and *not* the 'checker'
 
227
        attribute."""
22
228
        self.name = name
23
 
        self.dn = dn
24
 
        if password:
25
 
            self.password = password
26
 
        elif passfile:
27
 
            self.password = open(passfile).readall()
 
229
        logger.debug(u"Creating client %r", self.name)
 
230
        # Uppercase and remove spaces from fingerprint for later
 
231
        # comparison purposes with return value from the fingerprint()
 
232
        # function
 
233
        self.fingerprint = config["fingerprint"].upper()\
 
234
                           .replace(u" ", u"")
 
235
        logger.debug(u"  Fingerprint: %s", self.fingerprint)
 
236
        if "secret" in config:
 
237
            self.secret = config["secret"].decode(u"base64")
 
238
        elif "secfile" in config:
 
239
            sf = open(config["secfile"])
 
240
            self.secret = sf.read()
 
241
            sf.close()
28
242
        else:
29
 
            print "No Password or Passfile in client config file"
30
 
            # raise RuntimeError XXX
31
 
            self.password = "gazonk"
32
 
        self.fqdn = fqdn                # string
 
243
            raise TypeError(u"No secret or secfile for client %s"
 
244
                            % self.name)
 
245
        self.host = config.get("host", "")
33
246
        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
 
247
        self.last_checked_ok = None
 
248
        self.timeout = string_to_delta(config["timeout"])
 
249
        self.interval = string_to_delta(config["interval"])
 
250
        self.stop_hook = stop_hook
 
251
        self.checker = None
 
252
        self.checker_initiator_tag = None
 
253
        self.stop_initiator_tag = None
 
254
        self.checker_callback_tag = None
 
255
        self.check_command = config["checker"]
 
256
    def start(self):
 
257
        """Start this client's checker and timeout hooks"""
 
258
        # Schedule a new checker to be started an 'interval' from now,
 
259
        # and every interval from then on.
 
260
        self.checker_initiator_tag = gobject.timeout_add\
 
261
                                     (self._interval_milliseconds,
 
262
                                      self.start_checker)
 
263
        # Also start a new checker *right now*.
 
264
        self.start_checker()
 
265
        # Schedule a stop() when 'timeout' has passed
 
266
        self.stop_initiator_tag = gobject.timeout_add\
 
267
                                  (self._timeout_milliseconds,
 
268
                                   self.stop)
 
269
    def stop(self):
 
270
        """Stop this client.
 
271
        The possibility that a client might be restarted is left open,
 
272
        but not currently used."""
 
273
        # If this client doesn't have a secret, it is already stopped.
 
274
        if hasattr(self, "secret") and self.secret:
 
275
            logger.info(u"Stopping client %s", self.name)
 
276
            self.secret = None
 
277
        else:
 
278
            return False
 
279
        if getattr(self, "stop_initiator_tag", False):
 
280
            gobject.source_remove(self.stop_initiator_tag)
 
281
            self.stop_initiator_tag = None
 
282
        if getattr(self, "checker_initiator_tag", False):
 
283
            gobject.source_remove(self.checker_initiator_tag)
 
284
            self.checker_initiator_tag = None
 
285
        self.stop_checker()
 
286
        if self.stop_hook:
 
287
            self.stop_hook(self)
 
288
        # Do not run this again if called by a gobject.timeout_add
 
289
        return False
 
290
    def __del__(self):
 
291
        self.stop_hook = None
 
292
        self.stop()
 
293
    def checker_callback(self, pid, condition):
 
294
        """The checker has completed, so take appropriate actions."""
 
295
        now = datetime.datetime.now()
 
296
        self.checker_callback_tag = None
 
297
        self.checker = None
 
298
        if os.WIFEXITED(condition) \
 
299
               and (os.WEXITSTATUS(condition) == 0):
 
300
            logger.info(u"Checker for %(name)s succeeded",
 
301
                        vars(self))
 
302
            self.last_checked_ok = now
 
303
            gobject.source_remove(self.stop_initiator_tag)
 
304
            self.stop_initiator_tag = gobject.timeout_add\
 
305
                                      (self._timeout_milliseconds,
 
306
                                       self.stop)
 
307
        elif not os.WIFEXITED(condition):
 
308
            logger.warning(u"Checker for %(name)s crashed?",
 
309
                           vars(self))
 
310
        else:
 
311
            logger.info(u"Checker for %(name)s failed",
 
312
                        vars(self))
57
313
    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
 
314
        """Start a new checker subprocess if one is not running.
 
315
        If a checker already exists, leave it running and do
 
316
        nothing."""
 
317
        # The reason for not killing a running checker is that if we
 
318
        # did that, then if a checker (for some reason) started
 
319
        # running slowly and taking more than 'interval' time, the
 
320
        # client would inevitably timeout, since no checker would get
 
321
        # a chance to run to completion.  If we instead leave running
 
322
        # checkers alone, the checker would have to take more time
 
323
        # than 'timeout' for the client to be declared invalid, which
 
324
        # is as it should be.
 
325
        if self.checker is None:
 
326
            try:
 
327
                # In case check_command has exactly one % operator
 
328
                command = self.check_command % self.host
 
329
            except TypeError:
 
330
                # Escape attributes for the shell
 
331
                escaped_attrs = dict((key, re.escape(str(val)))
 
332
                                     for key, val in
 
333
                                     vars(self).iteritems())
 
334
                try:
 
335
                    command = self.check_command % escaped_attrs
 
336
                except TypeError, error:
 
337
                    logger.error(u'Could not format string "%s":'
 
338
                                 u' %s', self.check_command, error)
 
339
                    return True # Try again later
 
340
            try:
 
341
                logger.info(u"Starting checker %r for %s",
 
342
                            command, self.name)
 
343
                # We don't need to redirect stdout and stderr, since
 
344
                # in normal mode, that is already done by daemon(),
 
345
                # and in debug mode we don't want to.  (Stdin is
 
346
                # always replaced by /dev/null.)
 
347
                self.checker = subprocess.Popen(command,
 
348
                                                close_fds=True,
 
349
                                                shell=True, cwd="/")
 
350
                self.checker_callback_tag = gobject.child_watch_add\
 
351
                                            (self.checker.pid,
 
352
                                             self.checker_callback)
 
353
            except OSError, error:
 
354
                logger.error(u"Failed to start subprocess: %s",
 
355
                             error)
 
356
        # Re-run this periodically if run by gobject.timeout_add
 
357
        return True
67
358
    def stop_checker(self):
68
 
        if self.checker is None:
 
359
        """Force the checker process, if any, to stop."""
 
360
        if self.checker_callback_tag:
 
361
            gobject.source_remove(self.checker_callback_tag)
 
362
            self.checker_callback_tag = None
 
363
        if getattr(self, "checker", None) is None:
69
364
            return
70
 
        os.kill(self.checker.pid, signal.SIGTERM)
71
 
        if self.checker.poll() is None:
72
 
            os.kill(self.checker.pid, signal.SIGKILL)
 
365
        logger.debug(u"Stopping checker for %(name)s", vars(self))
 
366
        try:
 
367
            os.kill(self.checker.pid, signal.SIGTERM)
 
368
            #os.sleep(0.5)
 
369
            #if self.checker.poll() is None:
 
370
            #    os.kill(self.checker.pid, signal.SIGKILL)
 
371
        except OSError, error:
 
372
            if error.errno != errno.ESRCH: # No such process
 
373
                raise
73
374
        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"
 
375
    def still_valid(self):
 
376
        """Has the timeout not yet passed for this client?"""
 
377
        now = datetime.datetime.now()
 
378
        if self.last_checked_ok is None:
 
379
            return now < (self.created + self.timeout)
 
380
        else:
 
381
            return now < (self.last_checked_ok + self.timeout)
 
382
 
 
383
 
 
384
def peer_certificate(session):
 
385
    "Return the peer's OpenPGP certificate as a bytestring"
 
386
    # If not an OpenPGP certificate...
 
387
    if gnutls.library.functions.gnutls_certificate_type_get\
 
388
            (session._c_object) \
 
389
           != gnutls.library.constants.GNUTLS_CRT_OPENPGP:
 
390
        # ...do the normal thing
 
391
        return session.peer_certificate
 
392
    list_size = ctypes.c_uint()
 
393
    cert_list = gnutls.library.functions.gnutls_certificate_get_peers\
 
394
        (session._c_object, ctypes.byref(list_size))
 
395
    if list_size.value == 0:
 
396
        return None
 
397
    cert = cert_list[0]
 
398
    return ctypes.string_at(cert.data, cert.size)
 
399
 
 
400
 
 
401
def fingerprint(openpgp):
 
402
    "Convert an OpenPGP bytestring to a hexdigit fingerprint string"
 
403
    # New GnuTLS "datum" with the OpenPGP public key
 
404
    datum = gnutls.library.types.gnutls_datum_t\
 
405
        (ctypes.cast(ctypes.c_char_p(openpgp),
 
406
                     ctypes.POINTER(ctypes.c_ubyte)),
 
407
         ctypes.c_uint(len(openpgp)))
 
408
    # New empty GnuTLS certificate
 
409
    crt = gnutls.library.types.gnutls_openpgp_crt_t()
 
410
    gnutls.library.functions.gnutls_openpgp_crt_init\
 
411
        (ctypes.byref(crt))
 
412
    # Import the OpenPGP public key into the certificate
 
413
    gnutls.library.functions.gnutls_openpgp_crt_import\
 
414
                    (crt, ctypes.byref(datum),
 
415
                     gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
 
416
    # Verify the self signature in the key
 
417
    crtverify = ctypes.c_uint();
 
418
    gnutls.library.functions.gnutls_openpgp_crt_verify_self\
 
419
        (crt, 0, ctypes.byref(crtverify))
 
420
    if crtverify.value != 0:
 
421
        gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
 
422
        raise gnutls.errors.CertificateSecurityError("Verify failed")
 
423
    # New buffer for the fingerprint
 
424
    buffer = ctypes.create_string_buffer(20)
 
425
    buffer_length = ctypes.c_size_t()
 
426
    # Get the fingerprint from the certificate into the buffer
 
427
    gnutls.library.functions.gnutls_openpgp_crt_get_fingerprint\
 
428
        (crt, ctypes.byref(buffer), ctypes.byref(buffer_length))
 
429
    # Deinit the certificate
 
430
    gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
 
431
    # Convert the buffer to a Python bytestring
 
432
    fpr = ctypes.string_at(buffer, buffer_length.value)
 
433
    # Convert the bytestring to hexadecimal notation
 
434
    hex_fpr = u''.join(u"%02X" % ord(char) for char in fpr)
 
435
    return hex_fpr
141
436
 
142
437
 
143
438
class tcp_handler(SocketServer.BaseRequestHandler, object):
 
439
    """A TCP request handler class.
 
440
    Instantiated by IPv6_TCPServer for each request to handle it.
 
441
    Note: This will run in its own forked process."""
 
442
    
144
443
    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
 
444
        logger.info(u"TCP connection from: %s",
 
445
                     unicode(self.client_address))
 
446
        session = gnutls.connection.ClientSession\
 
447
                  (self.request, gnutls.connection.X509Credentials())
 
448
        
 
449
        line = self.request.makefile().readline()
 
450
        logger.debug(u"Protocol version: %r", line)
 
451
        try:
 
452
            if int(line.strip().split()[0]) > 1:
 
453
                raise RuntimeError
 
454
        except (ValueError, IndexError, RuntimeError), error:
 
455
            logger.error(u"Unknown protocol version: %s", error)
 
456
            return
 
457
        
 
458
        # Note: gnutls.connection.X509Credentials is really a generic
 
459
        # GnuTLS certificate credentials object so long as no X.509
 
460
        # keys are added to it.  Therefore, we can use it here despite
 
461
        # using OpenPGP certificates.
 
462
        
 
463
        #priority = ':'.join(("NONE", "+VERS-TLS1.1", "+AES-256-CBC",
 
464
        #                "+SHA1", "+COMP-NULL", "+CTYPE-OPENPGP",
 
465
        #                "+DHE-DSS"))
 
466
        priority = "NORMAL"             # Fallback default, since this
 
467
                                        # MUST be set.
 
468
        if self.server.settings["priority"]:
 
469
            priority = self.server.settings["priority"]
 
470
        gnutls.library.functions.gnutls_priority_set_direct\
 
471
            (session._c_object, priority, None);
 
472
        
 
473
        try:
 
474
            session.handshake()
 
475
        except gnutls.errors.GNUTLSError, error:
 
476
            logger.warning(u"Handshake failed: %s", error)
 
477
            # Do not run session.bye() here: the session is not
 
478
            # established.  Just abandon the request.
 
479
            return
 
480
        try:
 
481
            fpr = fingerprint(peer_certificate(session))
 
482
        except (TypeError, gnutls.errors.GNUTLSError), error:
 
483
            logger.warning(u"Bad certificate: %s", error)
 
484
            session.bye()
 
485
            return
 
486
        logger.debug(u"Fingerprint: %s", fpr)
 
487
        client = None
 
488
        for c in self.server.clients:
 
489
            if c.fingerprint == fpr:
 
490
                client = c
 
491
                break
 
492
        if not client:
 
493
            logger.warning(u"Client not found for fingerprint: %s",
 
494
                           fpr)
 
495
            session.bye()
 
496
            return
 
497
        # Have to check if client.still_valid(), since it is possible
 
498
        # that the client timed out while establishing the GnuTLS
 
499
        # session.
 
500
        if not client.still_valid():
 
501
            logger.warning(u"Client %(name)s is invalid",
 
502
                           vars(client))
 
503
            session.bye()
 
504
            return
 
505
        sent_size = 0
 
506
        while sent_size < len(client.secret):
 
507
            sent = session.send(client.secret[sent_size:])
 
508
            logger.debug(u"Sent: %d, remaining: %d",
 
509
                         sent, len(client.secret)
 
510
                         - (sent_size + sent))
 
511
            sent_size += sent
167
512
        session.bye()
168
513
 
169
514
 
170
515
class IPv6_TCPServer(SocketServer.ForkingTCPServer, object):
171
 
    __metaclass__ = server_metaclass
172
 
    request_queue_size = 1024
173
 
 
174
 
 
175
 
in6addr_any = "::"
 
516
    """IPv6 TCP server.  Accepts 'None' as address and/or port.
 
517
    Attributes:
 
518
        settings:       Server settings
 
519
        clients:        Set() of Client objects
 
520
    """
 
521
    address_family = socket.AF_INET6
 
522
    def __init__(self, *args, **kwargs):
 
523
        if "settings" in kwargs:
 
524
            self.settings = kwargs["settings"]
 
525
            del kwargs["settings"]
 
526
        if "clients" in kwargs:
 
527
            self.clients = kwargs["clients"]
 
528
            del kwargs["clients"]
 
529
        return super(type(self), self).__init__(*args, **kwargs)
 
530
    def server_bind(self):
 
531
        """This overrides the normal server_bind() function
 
532
        to bind to an interface if one was specified, and also NOT to
 
533
        bind to an address or port if they were not specified."""
 
534
        if self.settings["interface"]:
 
535
            # 25 is from /usr/include/asm-i486/socket.h
 
536
            SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
 
537
            try:
 
538
                self.socket.setsockopt(socket.SOL_SOCKET,
 
539
                                       SO_BINDTODEVICE,
 
540
                                       self.settings["interface"])
 
541
            except socket.error, error:
 
542
                if error[0] == errno.EPERM:
 
543
                    logger.error(u"No permission to"
 
544
                                 u" bind to interface %s",
 
545
                                 self.settings["interface"])
 
546
                else:
 
547
                    raise error
 
548
        # Only bind(2) the socket if we really need to.
 
549
        if self.server_address[0] or self.server_address[1]:
 
550
            if not self.server_address[0]:
 
551
                in6addr_any = "::"
 
552
                self.server_address = (in6addr_any,
 
553
                                       self.server_address[1])
 
554
            elif not self.server_address[1]:
 
555
                self.server_address = (self.server_address[0],
 
556
                                       0)
 
557
#                 if self.settings["interface"]:
 
558
#                     self.server_address = (self.server_address[0],
 
559
#                                            0, # port
 
560
#                                            0, # flowinfo
 
561
#                                            if_nametoindex
 
562
#                                            (self.settings
 
563
#                                             ["interface"]))
 
564
            return super(type(self), self).server_bind()
 
565
 
176
566
 
177
567
def string_to_delta(interval):
178
568
    """Parse a string and return a datetime.timedelta
187
577
    datetime.timedelta(1)
188
578
    >>> string_to_delta(u'1w')
189
579
    datetime.timedelta(7)
 
580
    >>> string_to_delta('5m 30s')
 
581
    datetime.timedelta(0, 330)
190
582
    """
191
 
    try:
192
 
        suffix=unicode(interval[-1])
193
 
        value=int(interval[:-1])
194
 
        if suffix == u"d":
195
 
            delta = datetime.timedelta(value)
196
 
        elif suffix == u"s":
197
 
            delta = datetime.timedelta(0, value)
198
 
        elif suffix == u"m":
199
 
            delta = datetime.timedelta(0, 0, 0, 0, value)
200
 
        elif suffix == u"h":
201
 
            delta = datetime.timedelta(0, 0, 0, 0, 0, value)
202
 
        elif suffix == u"w":
203
 
            delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
204
 
        else:
 
583
    timevalue = datetime.timedelta(0)
 
584
    for s in interval.split():
 
585
        try:
 
586
            suffix=unicode(s[-1])
 
587
            value=int(s[:-1])
 
588
            if suffix == u"d":
 
589
                delta = datetime.timedelta(value)
 
590
            elif suffix == u"s":
 
591
                delta = datetime.timedelta(0, value)
 
592
            elif suffix == u"m":
 
593
                delta = datetime.timedelta(0, 0, 0, 0, value)
 
594
            elif suffix == u"h":
 
595
                delta = datetime.timedelta(0, 0, 0, 0, 0, value)
 
596
            elif suffix == u"w":
 
597
                delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
 
598
            else:
 
599
                raise ValueError
 
600
        except (ValueError, IndexError):
205
601
            raise ValueError
206
 
    except (ValueError, IndexError):
207
 
        raise ValueError
208
 
    return delta
 
602
        timevalue += delta
 
603
    return timevalue
 
604
 
 
605
 
 
606
def server_state_changed(state):
 
607
    """Derived from the Avahi example code"""
 
608
    if state == avahi.SERVER_COLLISION:
 
609
        logger.error(u"Zeroconf server name collision")
 
610
        service.remove()
 
611
    elif state == avahi.SERVER_RUNNING:
 
612
        service.add()
 
613
 
 
614
 
 
615
def entry_group_state_changed(state, error):
 
616
    """Derived from the Avahi example code"""
 
617
    logger.debug(u"Avahi state change: %i", state)
 
618
    
 
619
    if state == avahi.ENTRY_GROUP_ESTABLISHED:
 
620
        logger.debug(u"Zeroconf service established.")
 
621
    elif state == avahi.ENTRY_GROUP_COLLISION:
 
622
        logger.warning(u"Zeroconf service name collision.")
 
623
        service.rename()
 
624
    elif state == avahi.ENTRY_GROUP_FAILURE:
 
625
        logger.critical(u"Avahi: Error in group state changed %s",
 
626
                        unicode(error))
 
627
        raise AvahiGroupError("State changed: %s", str(error))
 
628
 
 
629
def if_nametoindex(interface):
 
630
    """Call the C function if_nametoindex(), or equivalent"""
 
631
    global if_nametoindex
 
632
    try:
 
633
        if "ctypes.util" not in sys.modules:
 
634
            import ctypes.util
 
635
        if_nametoindex = ctypes.cdll.LoadLibrary\
 
636
            (ctypes.util.find_library("c")).if_nametoindex
 
637
    except (OSError, AttributeError):
 
638
        if "struct" not in sys.modules:
 
639
            import struct
 
640
        if "fcntl" not in sys.modules:
 
641
            import fcntl
 
642
        def if_nametoindex(interface):
 
643
            "Get an interface index the hard way, i.e. using fcntl()"
 
644
            SIOCGIFINDEX = 0x8933  # From /usr/include/linux/sockios.h
 
645
            s = socket.socket()
 
646
            ifreq = fcntl.ioctl(s, SIOCGIFINDEX,
 
647
                                struct.pack("16s16x", interface))
 
648
            s.close()
 
649
            interface_index = struct.unpack("I", ifreq[16:20])[0]
 
650
            return interface_index
 
651
    return if_nametoindex(interface)
 
652
 
 
653
 
 
654
def daemon(nochdir = False, noclose = False):
 
655
    """See daemon(3).  Standard BSD Unix function.
 
656
    This should really exist as os.daemon, but it doesn't (yet)."""
 
657
    if os.fork():
 
658
        sys.exit()
 
659
    os.setsid()
 
660
    if not nochdir:
 
661
        os.chdir("/")
 
662
    if os.fork():
 
663
        sys.exit()
 
664
    if not noclose:
 
665
        # Close all standard open file descriptors
 
666
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
 
667
        if not stat.S_ISCHR(os.fstat(null).st_mode):
 
668
            raise OSError(errno.ENODEV,
 
669
                          "/dev/null not a character device")
 
670
        os.dup2(null, sys.stdin.fileno())
 
671
        os.dup2(null, sys.stdout.fileno())
 
672
        os.dup2(null, sys.stderr.fileno())
 
673
        if null > 2:
 
674
            os.close(null)
209
675
 
210
676
 
211
677
def main():
212
 
    parser = OptionParser()
 
678
    global main_loop_started
 
679
    main_loop_started = False
 
680
    
 
681
    parser = OptionParser(version = "%%prog %s" % version)
213
682
    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,
 
683
                      metavar="IF", help="Bind to interface IF")
 
684
    parser.add_option("-a", "--address", type="string",
 
685
                      help="Address to listen for requests on")
 
686
    parser.add_option("-p", "--port", type="int",
229
687
                      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
688
    parser.add_option("--check", action="store_true", default=False,
239
689
                      help="Run self-test")
 
690
    parser.add_option("--debug", action="store_true",
 
691
                      help="Debug mode; run in foreground and log to"
 
692
                      " terminal")
 
693
    parser.add_option("--priority", type="string", help="GnuTLS"
 
694
                      " priority string (see GnuTLS documentation)")
 
695
    parser.add_option("--servicename", type="string", metavar="NAME",
 
696
                      help="Zeroconf service name")
 
697
    parser.add_option("--configdir", type="string",
 
698
                      default="/etc/mandos", metavar="DIR",
 
699
                      help="Directory to search for configuration"
 
700
                      " files")
240
701
    (options, args) = parser.parse_args()
241
 
 
 
702
    
242
703
    if options.check:
243
704
        import doctest
244
705
        doctest.testmod()
245
706
        sys.exit()
246
707
    
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),
 
708
    # Default values for config file for server-global settings
 
709
    server_defaults = { "interface": "",
 
710
                        "address": "",
 
711
                        "port": "",
 
712
                        "debug": "False",
 
713
                        "priority":
 
714
                        "SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP",
 
715
                        "servicename": "Mandos",
 
716
                        }
 
717
    
 
718
    # Parse config file for server-global settings
 
719
    server_config = ConfigParser.SafeConfigParser(server_defaults)
 
720
    del server_defaults
 
721
    server_config.read(os.path.join(options.configdir, "mandos.conf"))
 
722
    # Convert the SafeConfigParser object to a dict
 
723
    server_settings = server_config.defaults()
 
724
    # Use getboolean on the boolean config option
 
725
    server_settings["debug"] = server_config.getboolean\
 
726
                               ("DEFAULT", "debug")
 
727
    del server_config
 
728
    
 
729
    # Override the settings from the config file with command line
 
730
    # options, if set.
 
731
    for option in ("interface", "address", "port", "debug",
 
732
                   "priority", "servicename", "configdir"):
 
733
        value = getattr(options, option)
 
734
        if value is not None:
 
735
            server_settings[option] = value
 
736
    del options
 
737
    # Now we have our good server settings in "server_settings"
 
738
    
 
739
    debug = server_settings["debug"]
 
740
    
 
741
    if not debug:
 
742
        syslogger.setLevel(logging.WARNING)
 
743
        console.setLevel(logging.WARNING)
 
744
    
 
745
    if server_settings["servicename"] != "Mandos":
 
746
        syslogger.setFormatter(logging.Formatter\
 
747
                               ('Mandos (%s): %%(levelname)s:'
 
748
                                ' %%(message)s'
 
749
                                % server_settings["servicename"]))
 
750
    
 
751
    # Parse config file with clients
 
752
    client_defaults = { "timeout": "1h",
 
753
                        "interval": "5m",
 
754
                        "checker": "fping -q -- %(host)s",
 
755
                        "host": "",
 
756
                        }
 
757
    client_config = ConfigParser.SafeConfigParser(client_defaults)
 
758
    client_config.read(os.path.join(server_settings["configdir"],
 
759
                                    "clients.conf"))
 
760
    
 
761
    global service
 
762
    service = AvahiService(name = server_settings["servicename"],
 
763
                           type = "_mandos._tcp", );
 
764
    if server_settings["interface"]:
 
765
        service.interface = if_nametoindex\
 
766
                            (server_settings["interface"])
 
767
    
 
768
    global main_loop
 
769
    global bus
 
770
    global server
 
771
    # From the Avahi example code
 
772
    DBusGMainLoop(set_as_default=True )
 
773
    main_loop = gobject.MainLoop()
 
774
    bus = dbus.SystemBus()
 
775
    server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
 
776
                                           avahi.DBUS_PATH_SERVER),
 
777
                            avahi.DBUS_INTERFACE_SERVER)
 
778
    # End of Avahi example code
 
779
    
 
780
    clients = Set()
 
781
    def remove_from_clients(client):
 
782
        clients.remove(client)
 
783
        if not clients:
 
784
            logger.critical(u"No clients left, exiting")
 
785
            sys.exit()
 
786
    
 
787
    clients.update(Set(Client(name = section,
 
788
                              stop_hook = remove_from_clients,
 
789
                              config
 
790
                              = dict(client_config.items(section)))
 
791
                       for section in client_config.sections()))
 
792
    if not clients:
 
793
        logger.critical(u"No clients defined")
 
794
        sys.exit(1)
 
795
    
 
796
    if debug:
 
797
        # Redirect stdin so all checkers get /dev/null
 
798
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
 
799
        os.dup2(null, sys.stdin.fileno())
 
800
        if null > 2:
 
801
            os.close(null)
 
802
    else:
 
803
        # No console logging
 
804
        logger.removeHandler(console)
 
805
        # Close all input and output, do double fork, etc.
 
806
        daemon()
 
807
    
 
808
    pidfilename = "/var/run/mandos/mandos.pid"
 
809
    pid = os.getpid()
 
810
    try:
 
811
        pidfile = open(pidfilename, "w")
 
812
        pidfile.write(str(pid) + "\n")
 
813
        pidfile.close()
 
814
        del pidfile
 
815
    except IOError, err:
 
816
        logger.error(u"Could not write %s file with PID %d",
 
817
                     pidfilename, os.getpid())
 
818
    
 
819
    def cleanup():
 
820
        "Cleanup function; run on exit"
 
821
        global group
 
822
        # From the Avahi example code
 
823
        if not group is None:
 
824
            group.Free()
 
825
            group = None
 
826
        # End of Avahi example code
 
827
        
 
828
        while clients:
 
829
            client = clients.pop()
 
830
            client.stop_hook = None
 
831
            client.stop()
 
832
    
 
833
    atexit.register(cleanup)
 
834
    
 
835
    if not debug:
 
836
        signal.signal(signal.SIGINT, signal.SIG_IGN)
 
837
    signal.signal(signal.SIGHUP, lambda signum, frame: sys.exit())
 
838
    signal.signal(signal.SIGTERM, lambda signum, frame: sys.exit())
 
839
    
 
840
    for client in clients:
 
841
        client.start()
 
842
    
 
843
    tcp_server = IPv6_TCPServer((server_settings["address"],
 
844
                                 server_settings["port"]),
277
845
                                tcp_handler,
278
 
                                options=options,
279
 
                                clients=clients,
280
 
                                credentials=cred)
281
 
    
282
 
    while True:
 
846
                                settings=server_settings,
 
847
                                clients=clients)
 
848
    # Find out what port we got
 
849
    service.port = tcp_server.socket.getsockname()[1]
 
850
    logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
 
851
                u" scope_id %d" % tcp_server.socket.getsockname())
 
852
    
 
853
    #service.interface = tcp_server.socket.getsockname()[3]
 
854
    
 
855
    try:
 
856
        # From the Avahi example code
 
857
        server.connect_to_signal("StateChanged", server_state_changed)
283
858
        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__":
 
859
            server_state_changed(server.GetState())
 
860
        except dbus.exceptions.DBusException, error:
 
861
            logger.critical(u"DBusException: %s", error)
 
862
            sys.exit(1)
 
863
        # End of Avahi example code
 
864
        
 
865
        gobject.io_add_watch(tcp_server.fileno(), gobject.IO_IN,
 
866
                             lambda *args, **kwargs:
 
867
                             tcp_server.handle_request\
 
868
                             (*args[2:], **kwargs) or True)
 
869
        
 
870
        logger.debug(u"Starting main loop")
 
871
        main_loop_started = True
 
872
        main_loop.run()
 
873
    except AvahiError, error:
 
874
        logger.critical(u"AvahiError: %s" + unicode(error))
 
875
        sys.exit(1)
 
876
    except KeyboardInterrupt:
 
877
        if debug:
 
878
            print
 
879
 
 
880
if __name__ == '__main__':
300
881
    main()
301