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* plugin-runner.c (handle_sigchld): Loop until all exited children
                                    have been wait()ed for.

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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 <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
 
48
import re
 
49
import os
 
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
version = "1.0"
 
65
 
 
66
logger = logging.Logger('mandos')
 
67
syslogger = logging.handlers.SysLogHandler\
 
68
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON,
 
69
             address = "/dev/log")
 
70
syslogger.setFormatter(logging.Formatter\
 
71
                        ('Mandos: %(levelname)s: %(message)s'))
 
72
logger.addHandler(syslogger)
 
73
 
 
74
console = logging.StreamHandler()
 
75
console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
 
76
                                       ' %(message)s'))
 
77
logger.addHandler(console)
 
78
 
 
79
class AvahiError(Exception):
 
80
    def __init__(self, value):
 
81
        self.value = value
 
82
    def __str__(self):
 
83
        return repr(self.value)
 
84
 
 
85
class AvahiServiceError(AvahiError):
 
86
    pass
 
87
 
 
88
class AvahiGroupError(AvahiError):
 
89
    pass
 
90
 
 
91
 
 
92
class AvahiService(object):
 
93
    """An Avahi (Zeroconf) service.
 
94
    Attributes:
 
95
    interface: integer; avahi.IF_UNSPEC or an interface index.
 
96
               Used to optionally bind to the specified interface.
 
97
    name: string; Example: 'Mandos'
 
98
    type: string; Example: '_mandos._tcp'.
 
99
                  See <http://www.dns-sd.org/ServiceTypes.html>
 
100
    port: integer; what port to announce
 
101
    TXT: list of strings; TXT record for the service
 
102
    domain: string; Domain to publish on, default to .local if empty.
 
103
    host: string; Host to publish records for, default is localhost
 
104
    max_renames: integer; maximum number of renames
 
105
    rename_count: integer; counter so we only rename after collisions
 
106
                  a sensible number of times
 
107
    """
 
108
    def __init__(self, interface = avahi.IF_UNSPEC, name = None,
 
109
                 type = None, port = None, TXT = None, domain = "",
 
110
                 host = "", max_renames = 32768):
 
111
        self.interface = interface
 
112
        self.name = name
 
113
        self.type = type
 
114
        self.port = port
 
115
        if TXT is None:
 
116
            self.TXT = []
 
117
        else:
 
118
            self.TXT = TXT
 
119
        self.domain = domain
 
120
        self.host = host
 
121
        self.rename_count = 0
 
122
        self.max_renames = max_renames
 
123
    def rename(self):
 
124
        """Derived from the Avahi example code"""
 
125
        if self.rename_count >= self.max_renames:
 
126
            logger.critical(u"No suitable service name found after %i"
 
127
                            u" retries, exiting.", rename_count)
 
128
            raise AvahiServiceError("Too many renames")
 
129
        self.name = server.GetAlternativeServiceName(self.name)
 
130
        logger.info(u"Changing name to %r ...", str(self.name))
 
131
        syslogger.setFormatter(logging.Formatter\
 
132
                               ('Mandos (%s): %%(levelname)s:'
 
133
                               ' %%(message)s' % self.name))
 
134
        self.remove()
 
135
        self.add()
 
136
        self.rename_count += 1
 
137
    def remove(self):
 
138
        """Derived from the Avahi example code"""
 
139
        if group is not None:
 
140
            group.Reset()
 
141
    def add(self):
 
142
        """Derived from the Avahi example code"""
 
143
        global group
 
144
        if group is None:
 
145
            group = dbus.Interface\
 
146
                    (bus.get_object(avahi.DBUS_NAME,
 
147
                                    server.EntryGroupNew()),
 
148
                     avahi.DBUS_INTERFACE_ENTRY_GROUP)
 
149
            group.connect_to_signal('StateChanged',
 
150
                                    entry_group_state_changed)
 
151
        logger.debug(u"Adding service '%s' of type '%s' ...",
 
152
                     service.name, service.type)
 
153
        group.AddService(
 
154
                self.interface,         # interface
 
155
                avahi.PROTO_INET6,      # protocol
 
156
                dbus.UInt32(0),         # flags
 
157
                self.name, self.type,
 
158
                self.domain, self.host,
 
159
                dbus.UInt16(self.port),
 
160
                avahi.string_array_to_txt_array(self.TXT))
 
161
        group.Commit()
 
162
 
 
163
# From the Avahi example code:
 
164
group = None                            # our entry group
 
165
# End of Avahi example code
14
166
 
15
167
 
16
168
class Client(object):
17
 
    def __init__(self, name=None, options=None, dn=None,
18
 
                 password=None, passfile=None, fqdn=None,
19
 
                 timeout=None, interval=-1):
 
169
    """A representation of a client host served by this server.
 
170
    Attributes:
 
171
    name:      string; from the config file, used in log messages
 
172
    fingerprint: string (40 or 32 hexadecimal digits); used to
 
173
                 uniquely identify the client
 
174
    secret:    bytestring; sent verbatim (over TLS) to client
 
175
    host:      string; available for use by the checker command
 
176
    created:   datetime.datetime(); object creation, not client host
 
177
    last_checked_ok: datetime.datetime() or None if not yet checked OK
 
178
    timeout:   datetime.timedelta(); How long from last_checked_ok
 
179
                                     until this client is invalid
 
180
    interval:  datetime.timedelta(); How often to start a new checker
 
181
    stop_hook: If set, called by stop() as stop_hook(self)
 
182
    checker:   subprocess.Popen(); a running checker process used
 
183
                                   to see if the client lives.
 
184
                                   'None' if no process is running.
 
185
    checker_initiator_tag: a gobject event source tag, or None
 
186
    stop_initiator_tag:    - '' -
 
187
    checker_callback_tag:  - '' -
 
188
    checker_command: string; External command which is run to check if
 
189
                     client lives.  %() expansions are done at
 
190
                     runtime with vars(self) as dict, so that for
 
191
                     instance %(name)s can be used in the command.
 
192
    Private attibutes:
 
193
    _timeout: Real variable for 'timeout'
 
194
    _interval: Real variable for 'interval'
 
195
    _timeout_milliseconds: Used when calling gobject.timeout_add()
 
196
    _interval_milliseconds: - '' -
 
197
    """
 
198
    def _set_timeout(self, timeout):
 
199
        "Setter function for 'timeout' attribute"
 
200
        self._timeout = timeout
 
201
        self._timeout_milliseconds = ((self.timeout.days
 
202
                                       * 24 * 60 * 60 * 1000)
 
203
                                      + (self.timeout.seconds * 1000)
 
204
                                      + (self.timeout.microseconds
 
205
                                         // 1000))
 
206
    timeout = property(lambda self: self._timeout,
 
207
                       _set_timeout)
 
208
    del _set_timeout
 
209
    def _set_interval(self, interval):
 
210
        "Setter function for 'interval' attribute"
 
211
        self._interval = interval
 
212
        self._interval_milliseconds = ((self.interval.days
 
213
                                        * 24 * 60 * 60 * 1000)
 
214
                                       + (self.interval.seconds
 
215
                                          * 1000)
 
216
                                       + (self.interval.microseconds
 
217
                                          // 1000))
 
218
    interval = property(lambda self: self._interval,
 
219
                        _set_interval)
 
220
    del _set_interval
 
221
    def __init__(self, name = None, stop_hook=None, config={}):
 
222
        """Note: the 'checker' key in 'config' sets the
 
223
        'checker_command' attribute and *not* the 'checker'
 
224
        attribute."""
20
225
        self.name = name
21
 
        self.dn = dn
22
 
        if password:
23
 
            self.password = password
24
 
        elif passfile:
25
 
            self.password = open(passfile).readall()
 
226
        logger.debug(u"Creating client %r", self.name)
 
227
        # Uppercase and remove spaces from fingerprint for later
 
228
        # comparison purposes with return value from the fingerprint()
 
229
        # function
 
230
        self.fingerprint = config["fingerprint"].upper()\
 
231
                           .replace(u" ", u"")
 
232
        logger.debug(u"  Fingerprint: %s", self.fingerprint)
 
233
        if "secret" in config:
 
234
            self.secret = config["secret"].decode(u"base64")
 
235
        elif "secfile" in config:
 
236
            sf = open(config["secfile"])
 
237
            self.secret = sf.read()
 
238
            sf.close()
26
239
        else:
27
 
            print "No Password or Passfile in client config file"
28
 
            # raise RuntimeError XXX
29
 
            self.password = "gazonk"
30
 
        self.fqdn = fqdn
 
240
            raise TypeError(u"No secret or secfile for client %s"
 
241
                            % self.name)
 
242
        self.host = config.get("host", "")
31
243
        self.created = datetime.datetime.now()
32
 
        self.last_seen = None
33
 
        if timeout is None:
34
 
            timeout = options.timeout
35
 
        self.timeout = timeout
36
 
        if interval == -1:
37
 
            interval = options.interval
38
 
        self.interval = interval
39
 
        self.next_check = datetime.datetime.now()
40
 
 
41
 
 
42
 
class server_metaclass(type):
43
 
    "Common behavior for the UDP and TCP server classes"
44
 
    def __new__(cls, name, bases, attrs):
45
 
        attrs["address_family"] = socket.AF_INET6
46
 
        attrs["allow_reuse_address"] = True
47
 
        def server_bind(self):
48
 
            if self.options.interface:
49
 
                if not hasattr(socket, "SO_BINDTODEVICE"):
50
 
                    # From /usr/include/asm-i486/socket.h
51
 
                    socket.SO_BINDTODEVICE = 25
 
244
        self.last_checked_ok = None
 
245
        self.timeout = string_to_delta(config["timeout"])
 
246
        self.interval = string_to_delta(config["interval"])
 
247
        self.stop_hook = stop_hook
 
248
        self.checker = None
 
249
        self.checker_initiator_tag = None
 
250
        self.stop_initiator_tag = None
 
251
        self.checker_callback_tag = None
 
252
        self.check_command = config["checker"]
 
253
    def start(self):
 
254
        """Start this client's checker and timeout hooks"""
 
255
        # Schedule a new checker to be started an 'interval' from now,
 
256
        # and every interval from then on.
 
257
        self.checker_initiator_tag = gobject.timeout_add\
 
258
                                     (self._interval_milliseconds,
 
259
                                      self.start_checker)
 
260
        # Also start a new checker *right now*.
 
261
        self.start_checker()
 
262
        # Schedule a stop() when 'timeout' has passed
 
263
        self.stop_initiator_tag = gobject.timeout_add\
 
264
                                  (self._timeout_milliseconds,
 
265
                                   self.stop)
 
266
    def stop(self):
 
267
        """Stop this client.
 
268
        The possibility that a client might be restarted is left open,
 
269
        but not currently used."""
 
270
        # If this client doesn't have a secret, it is already stopped.
 
271
        if hasattr(self, "secret") and self.secret:
 
272
            logger.info(u"Stopping client %s", self.name)
 
273
            self.secret = None
 
274
        else:
 
275
            return False
 
276
        if getattr(self, "stop_initiator_tag", False):
 
277
            gobject.source_remove(self.stop_initiator_tag)
 
278
            self.stop_initiator_tag = None
 
279
        if getattr(self, "checker_initiator_tag", False):
 
280
            gobject.source_remove(self.checker_initiator_tag)
 
281
            self.checker_initiator_tag = None
 
282
        self.stop_checker()
 
283
        if self.stop_hook:
 
284
            self.stop_hook(self)
 
285
        # Do not run this again if called by a gobject.timeout_add
 
286
        return False
 
287
    def __del__(self):
 
288
        self.stop_hook = None
 
289
        self.stop()
 
290
    def checker_callback(self, pid, condition):
 
291
        """The checker has completed, so take appropriate actions."""
 
292
        now = datetime.datetime.now()
 
293
        self.checker_callback_tag = None
 
294
        self.checker = None
 
295
        if os.WIFEXITED(condition) \
 
296
               and (os.WEXITSTATUS(condition) == 0):
 
297
            logger.info(u"Checker for %(name)s succeeded",
 
298
                        vars(self))
 
299
            self.last_checked_ok = now
 
300
            gobject.source_remove(self.stop_initiator_tag)
 
301
            self.stop_initiator_tag = gobject.timeout_add\
 
302
                                      (self._timeout_milliseconds,
 
303
                                       self.stop)
 
304
        elif not os.WIFEXITED(condition):
 
305
            logger.warning(u"Checker for %(name)s crashed?",
 
306
                           vars(self))
 
307
        else:
 
308
            logger.info(u"Checker for %(name)s failed",
 
309
                        vars(self))
 
310
    def start_checker(self):
 
311
        """Start a new checker subprocess if one is not running.
 
312
        If a checker already exists, leave it running and do
 
313
        nothing."""
 
314
        # The reason for not killing a running checker is that if we
 
315
        # did that, then if a checker (for some reason) started
 
316
        # running slowly and taking more than 'interval' time, the
 
317
        # client would inevitably timeout, since no checker would get
 
318
        # a chance to run to completion.  If we instead leave running
 
319
        # checkers alone, the checker would have to take more time
 
320
        # than 'timeout' for the client to be declared invalid, which
 
321
        # is as it should be.
 
322
        if self.checker is None:
 
323
            try:
 
324
                # In case check_command has exactly one % operator
 
325
                command = self.check_command % self.host
 
326
            except TypeError:
 
327
                # Escape attributes for the shell
 
328
                escaped_attrs = dict((key, re.escape(str(val)))
 
329
                                     for key, val in
 
330
                                     vars(self).iteritems())
52
331
                try:
53
 
                    self.socket.setsockopt(socket.SOL_SOCKET,
54
 
                                           socket.SO_BINDTODEVICE,
55
 
                                           self.options.interface)
56
 
                except socket.error, error:
57
 
                    if error[0] == errno.EPERM:
58
 
                        print "Warning: No permission to bind to interface", \
59
 
                              self.options.interface
60
 
                    else:
61
 
                        raise error
62
 
            return super(type(self), self).server_bind()
63
 
        attrs["server_bind"] = server_bind
64
 
        def init(self, *args, **kwargs):
65
 
            if "options" in kwargs:
66
 
                self.options = kwargs["options"]
67
 
                del kwargs["options"]
68
 
            if "clients" in kwargs:
69
 
                self.clients = kwargs["clients"]
70
 
                del kwargs["clients"]
71
 
            if "credentials" in kwargs:
72
 
                self.credentials = kwargs["credentials"]
73
 
                del kwargs["credentials"]
74
 
            return super(type(self), self).__init__(*args, **kwargs)
75
 
        attrs["__init__"] = init
76
 
        return type.__new__(cls, name, bases, attrs)
77
 
 
78
 
 
79
 
class udp_handler(SocketServer.DatagramRequestHandler, object):
80
 
    def handle(self):
81
 
        self.wfile.write("Polo")
82
 
        print "UDP request answered"
83
 
 
84
 
 
85
 
class IPv6_UDPServer(SocketServer.UDPServer, object):
86
 
    __metaclass__ = server_metaclass
87
 
    def verify_request(self, request, client_address):
88
 
        print "UDP request came"
89
 
        return request[0] == "Marco"
 
332
                    command = self.check_command % escaped_attrs
 
333
                except TypeError, error:
 
334
                    logger.error(u'Could not format string "%s":'
 
335
                                 u' %s', self.check_command, error)
 
336
                    return True # Try again later
 
337
            try:
 
338
                logger.info(u"Starting checker %r for %s",
 
339
                            command, self.name)
 
340
                # We don't need to redirect stdout and stderr, since
 
341
                # in normal mode, that is already done by daemon(),
 
342
                # and in debug mode we don't want to.  (Stdin is
 
343
                # always replaced by /dev/null.)
 
344
                self.checker = subprocess.Popen(command,
 
345
                                                close_fds=True,
 
346
                                                shell=True, cwd="/")
 
347
                self.checker_callback_tag = gobject.child_watch_add\
 
348
                                            (self.checker.pid,
 
349
                                             self.checker_callback)
 
350
            except OSError, error:
 
351
                logger.error(u"Failed to start subprocess: %s",
 
352
                             error)
 
353
        # Re-run this periodically if run by gobject.timeout_add
 
354
        return True
 
355
    def stop_checker(self):
 
356
        """Force the checker process, if any, to stop."""
 
357
        if self.checker_callback_tag:
 
358
            gobject.source_remove(self.checker_callback_tag)
 
359
            self.checker_callback_tag = None
 
360
        if getattr(self, "checker", None) is None:
 
361
            return
 
362
        logger.debug(u"Stopping checker for %(name)s", vars(self))
 
363
        try:
 
364
            os.kill(self.checker.pid, signal.SIGTERM)
 
365
            #os.sleep(0.5)
 
366
            #if self.checker.poll() is None:
 
367
            #    os.kill(self.checker.pid, signal.SIGKILL)
 
368
        except OSError, error:
 
369
            if error.errno != errno.ESRCH: # No such process
 
370
                raise
 
371
        self.checker = None
 
372
    def still_valid(self):
 
373
        """Has the timeout not yet passed for this client?"""
 
374
        now = datetime.datetime.now()
 
375
        if self.last_checked_ok is None:
 
376
            return now < (self.created + self.timeout)
 
377
        else:
 
378
            return now < (self.last_checked_ok + self.timeout)
 
379
 
 
380
 
 
381
def peer_certificate(session):
 
382
    "Return the peer's OpenPGP certificate as a bytestring"
 
383
    # If not an OpenPGP certificate...
 
384
    if gnutls.library.functions.gnutls_certificate_type_get\
 
385
            (session._c_object) \
 
386
           != gnutls.library.constants.GNUTLS_CRT_OPENPGP:
 
387
        # ...do the normal thing
 
388
        return session.peer_certificate
 
389
    list_size = ctypes.c_uint()
 
390
    cert_list = gnutls.library.functions.gnutls_certificate_get_peers\
 
391
        (session._c_object, ctypes.byref(list_size))
 
392
    if list_size.value == 0:
 
393
        return None
 
394
    cert = cert_list[0]
 
395
    return ctypes.string_at(cert.data, cert.size)
 
396
 
 
397
 
 
398
def fingerprint(openpgp):
 
399
    "Convert an OpenPGP bytestring to a hexdigit fingerprint string"
 
400
    # New GnuTLS "datum" with the OpenPGP public key
 
401
    datum = gnutls.library.types.gnutls_datum_t\
 
402
        (ctypes.cast(ctypes.c_char_p(openpgp),
 
403
                     ctypes.POINTER(ctypes.c_ubyte)),
 
404
         ctypes.c_uint(len(openpgp)))
 
405
    # New empty GnuTLS certificate
 
406
    crt = gnutls.library.types.gnutls_openpgp_crt_t()
 
407
    gnutls.library.functions.gnutls_openpgp_crt_init\
 
408
        (ctypes.byref(crt))
 
409
    # Import the OpenPGP public key into the certificate
 
410
    gnutls.library.functions.gnutls_openpgp_crt_import\
 
411
                    (crt, ctypes.byref(datum),
 
412
                     gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
 
413
    # Verify the self signature in the key
 
414
    crtverify = ctypes.c_uint();
 
415
    gnutls.library.functions.gnutls_openpgp_crt_verify_self\
 
416
        (crt, ctypes.c_uint(0), ctypes.byref(crtverify))
 
417
    if crtverify.value != 0:
 
418
        gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
 
419
        raise gnutls.errors.CertificateSecurityError("Verify failed")
 
420
    # New buffer for the fingerprint
 
421
    buffer = ctypes.create_string_buffer(20)
 
422
    buffer_length = ctypes.c_size_t()
 
423
    # Get the fingerprint from the certificate into the buffer
 
424
    gnutls.library.functions.gnutls_openpgp_crt_get_fingerprint\
 
425
        (crt, ctypes.byref(buffer), ctypes.byref(buffer_length))
 
426
    # Deinit the certificate
 
427
    gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
 
428
    # Convert the buffer to a Python bytestring
 
429
    fpr = ctypes.string_at(buffer, buffer_length.value)
 
430
    # Convert the bytestring to hexadecimal notation
 
431
    hex_fpr = u''.join(u"%02X" % ord(char) for char in fpr)
 
432
    return hex_fpr
90
433
 
91
434
 
92
435
class tcp_handler(SocketServer.BaseRequestHandler, object):
 
436
    """A TCP request handler class.
 
437
    Instantiated by IPv6_TCPServer for each request to handle it.
 
438
    Note: This will run in its own forked process."""
 
439
    
93
440
    def handle(self):
94
 
        print "TCP request came"
95
 
        print "Request:", self.request
96
 
        print "Client Address:", self.client_address
97
 
        print "Server:", self.server
98
 
        session = gnutls.connection.ServerSession(self.request,
99
 
                                                  self.server.credentials)
100
 
        session.handshake()
101
 
        if session.peer_certificate:
102
 
            print "DN:", session.peer_certificate.subject
103
 
        try:
104
 
            session.verify_peer()
105
 
        except gnutls.errors.CertificateError, error:
106
 
            print "Verify failed", error
107
 
            session.bye()
108
 
            return
109
 
        try:
110
 
            session.send(dict((client.dn, client.password)
111
 
                              for client in self.server.clients)
112
 
                         [session.peer_certificate.subject])
113
 
        except KeyError:
114
 
            session.send("gazonk")
115
 
            # Log maybe? XXX
 
441
        logger.info(u"TCP connection from: %s",
 
442
                     unicode(self.client_address))
 
443
        session = gnutls.connection.ClientSession\
 
444
                  (self.request, gnutls.connection.X509Credentials())
 
445
        
 
446
        line = self.request.makefile().readline()
 
447
        logger.debug(u"Protocol version: %r", line)
 
448
        try:
 
449
            if int(line.strip().split()[0]) > 1:
 
450
                raise RuntimeError
 
451
        except (ValueError, IndexError, RuntimeError), error:
 
452
            logger.error(u"Unknown protocol version: %s", error)
 
453
            return
 
454
        
 
455
        # Note: gnutls.connection.X509Credentials is really a generic
 
456
        # GnuTLS certificate credentials object so long as no X.509
 
457
        # keys are added to it.  Therefore, we can use it here despite
 
458
        # using OpenPGP certificates.
 
459
        
 
460
        #priority = ':'.join(("NONE", "+VERS-TLS1.1", "+AES-256-CBC",
 
461
        #                "+SHA1", "+COMP-NULL", "+CTYPE-OPENPGP",
 
462
        #                "+DHE-DSS"))
 
463
        priority = "NORMAL"             # Fallback default, since this
 
464
                                        # MUST be set.
 
465
        if self.server.settings["priority"]:
 
466
            priority = self.server.settings["priority"]
 
467
        gnutls.library.functions.gnutls_priority_set_direct\
 
468
            (session._c_object, priority, None);
 
469
        
 
470
        try:
 
471
            session.handshake()
 
472
        except gnutls.errors.GNUTLSError, error:
 
473
            logger.warning(u"Handshake failed: %s", error)
 
474
            # Do not run session.bye() here: the session is not
 
475
            # established.  Just abandon the request.
 
476
            return
 
477
        try:
 
478
            fpr = fingerprint(peer_certificate(session))
 
479
        except (TypeError, gnutls.errors.GNUTLSError), error:
 
480
            logger.warning(u"Bad certificate: %s", error)
 
481
            session.bye()
 
482
            return
 
483
        logger.debug(u"Fingerprint: %s", fpr)
 
484
        client = None
 
485
        for c in self.server.clients:
 
486
            if c.fingerprint == fpr:
 
487
                client = c
 
488
                break
 
489
        if not client:
 
490
            logger.warning(u"Client not found for fingerprint: %s",
 
491
                           fpr)
 
492
            session.bye()
 
493
            return
 
494
        # Have to check if client.still_valid(), since it is possible
 
495
        # that the client timed out while establishing the GnuTLS
 
496
        # session.
 
497
        if not client.still_valid():
 
498
            logger.warning(u"Client %(name)s is invalid",
 
499
                           vars(client))
 
500
            session.bye()
 
501
            return
 
502
        sent_size = 0
 
503
        while sent_size < len(client.secret):
 
504
            sent = session.send(client.secret[sent_size:])
 
505
            logger.debug(u"Sent: %d, remaining: %d",
 
506
                         sent, len(client.secret)
 
507
                         - (sent_size + sent))
 
508
            sent_size += sent
116
509
        session.bye()
117
510
 
118
511
 
119
512
class IPv6_TCPServer(SocketServer.ForkingTCPServer, object):
120
 
    __metaclass__ = server_metaclass
121
 
    request_queue_size = 1024
122
 
 
123
 
 
124
 
in6addr_any = "::"
125
 
 
126
 
cred = None
 
513
    """IPv6 TCP server.  Accepts 'None' as address and/or port.
 
514
    Attributes:
 
515
        settings:       Server settings
 
516
        clients:        Set() of Client objects
 
517
    """
 
518
    address_family = socket.AF_INET6
 
519
    def __init__(self, *args, **kwargs):
 
520
        if "settings" in kwargs:
 
521
            self.settings = kwargs["settings"]
 
522
            del kwargs["settings"]
 
523
        if "clients" in kwargs:
 
524
            self.clients = kwargs["clients"]
 
525
            del kwargs["clients"]
 
526
        return super(type(self), self).__init__(*args, **kwargs)
 
527
    def server_bind(self):
 
528
        """This overrides the normal server_bind() function
 
529
        to bind to an interface if one was specified, and also NOT to
 
530
        bind to an address or port if they were not specified."""
 
531
        if self.settings["interface"]:
 
532
            # 25 is from /usr/include/asm-i486/socket.h
 
533
            SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
 
534
            try:
 
535
                self.socket.setsockopt(socket.SOL_SOCKET,
 
536
                                       SO_BINDTODEVICE,
 
537
                                       self.settings["interface"])
 
538
            except socket.error, error:
 
539
                if error[0] == errno.EPERM:
 
540
                    logger.error(u"No permission to"
 
541
                                 u" bind to interface %s",
 
542
                                 self.settings["interface"])
 
543
                else:
 
544
                    raise error
 
545
        # Only bind(2) the socket if we really need to.
 
546
        if self.server_address[0] or self.server_address[1]:
 
547
            if not self.server_address[0]:
 
548
                in6addr_any = "::"
 
549
                self.server_address = (in6addr_any,
 
550
                                       self.server_address[1])
 
551
            elif not self.server_address[1]:
 
552
                self.server_address = (self.server_address[0],
 
553
                                       0)
 
554
#                 if self.settings["interface"]:
 
555
#                     self.server_address = (self.server_address[0],
 
556
#                                            0, # port
 
557
#                                            0, # flowinfo
 
558
#                                            if_nametoindex
 
559
#                                            (self.settings
 
560
#                                             ["interface"]))
 
561
            return super(type(self), self).server_bind()
 
562
 
127
563
 
128
564
def string_to_delta(interval):
129
565
    """Parse a string and return a datetime.timedelta
138
574
    datetime.timedelta(1)
139
575
    >>> string_to_delta(u'1w')
140
576
    datetime.timedelta(7)
 
577
    >>> string_to_delta('5m 30s')
 
578
    datetime.timedelta(0, 330)
141
579
    """
142
 
    try:
143
 
        suffix=unicode(interval[-1])
144
 
        value=int(interval[:-1])
145
 
        if suffix == u"d":
146
 
            delta = datetime.timedelta(value)
147
 
        elif suffix == u"s":
148
 
            delta = datetime.timedelta(0, value)
149
 
        elif suffix == u"m":
150
 
            delta = datetime.timedelta(0, 0, 0, 0, value)
151
 
        elif suffix == u"h":
152
 
            delta = datetime.timedelta(0, 0, 0, 0, 0, value)
153
 
        elif suffix == u"w":
154
 
            delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
155
 
        else:
 
580
    timevalue = datetime.timedelta(0)
 
581
    for s in interval.split():
 
582
        try:
 
583
            suffix=unicode(s[-1])
 
584
            value=int(s[:-1])
 
585
            if suffix == u"d":
 
586
                delta = datetime.timedelta(value)
 
587
            elif suffix == u"s":
 
588
                delta = datetime.timedelta(0, value)
 
589
            elif suffix == u"m":
 
590
                delta = datetime.timedelta(0, 0, 0, 0, value)
 
591
            elif suffix == u"h":
 
592
                delta = datetime.timedelta(0, 0, 0, 0, 0, value)
 
593
            elif suffix == u"w":
 
594
                delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
 
595
            else:
 
596
                raise ValueError
 
597
        except (ValueError, IndexError):
156
598
            raise ValueError
157
 
    except (ValueError, IndexError):
158
 
        raise ValueError
159
 
    return delta
 
599
        timevalue += delta
 
600
    return timevalue
 
601
 
 
602
 
 
603
def server_state_changed(state):
 
604
    """Derived from the Avahi example code"""
 
605
    if state == avahi.SERVER_COLLISION:
 
606
        logger.error(u"Server name collision")
 
607
        service.remove()
 
608
    elif state == avahi.SERVER_RUNNING:
 
609
        service.add()
 
610
 
 
611
 
 
612
def entry_group_state_changed(state, error):
 
613
    """Derived from the Avahi example code"""
 
614
    logger.debug(u"state change: %i", state)
 
615
    
 
616
    if state == avahi.ENTRY_GROUP_ESTABLISHED:
 
617
        logger.debug(u"Service established.")
 
618
    elif state == avahi.ENTRY_GROUP_COLLISION:
 
619
        logger.warning(u"Service name collision.")
 
620
        service.rename()
 
621
    elif state == avahi.ENTRY_GROUP_FAILURE:
 
622
        logger.critical(u"Error in group state changed %s",
 
623
                        unicode(error))
 
624
        raise AvahiGroupError("State changed: %s", str(error))
 
625
 
 
626
def if_nametoindex(interface):
 
627
    """Call the C function if_nametoindex(), or equivalent"""
 
628
    global if_nametoindex
 
629
    try:
 
630
        if "ctypes.util" not in sys.modules:
 
631
            import ctypes.util
 
632
        if_nametoindex = ctypes.cdll.LoadLibrary\
 
633
            (ctypes.util.find_library("c")).if_nametoindex
 
634
    except (OSError, AttributeError):
 
635
        if "struct" not in sys.modules:
 
636
            import struct
 
637
        if "fcntl" not in sys.modules:
 
638
            import fcntl
 
639
        def if_nametoindex(interface):
 
640
            "Get an interface index the hard way, i.e. using fcntl()"
 
641
            SIOCGIFINDEX = 0x8933  # From /usr/include/linux/sockios.h
 
642
            s = socket.socket()
 
643
            ifreq = fcntl.ioctl(s, SIOCGIFINDEX,
 
644
                                struct.pack("16s16x", interface))
 
645
            s.close()
 
646
            interface_index = struct.unpack("I", ifreq[16:20])[0]
 
647
            return interface_index
 
648
    return if_nametoindex(interface)
 
649
 
 
650
 
 
651
def daemon(nochdir = False, noclose = False):
 
652
    """See daemon(3).  Standard BSD Unix function.
 
653
    This should really exist as os.daemon, but it doesn't (yet)."""
 
654
    if os.fork():
 
655
        sys.exit()
 
656
    os.setsid()
 
657
    if not nochdir:
 
658
        os.chdir("/")
 
659
    if os.fork():
 
660
        sys.exit()
 
661
    if not noclose:
 
662
        # Close all standard open file descriptors
 
663
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
 
664
        if not stat.S_ISCHR(os.fstat(null).st_mode):
 
665
            raise OSError(errno.ENODEV,
 
666
                          "/dev/null not a character device")
 
667
        os.dup2(null, sys.stdin.fileno())
 
668
        os.dup2(null, sys.stdout.fileno())
 
669
        os.dup2(null, sys.stderr.fileno())
 
670
        if null > 2:
 
671
            os.close(null)
 
672
 
160
673
 
161
674
def main():
162
 
    parser = OptionParser()
 
675
    global main_loop_started
 
676
    main_loop_started = False
 
677
    
 
678
    parser = OptionParser(version = "%%prog %s" % version)
163
679
    parser.add_option("-i", "--interface", type="string",
164
 
                      default="eth0", metavar="IF",
165
 
                      help="Interface to bind to")
166
 
    parser.add_option("--cert", type="string", default="cert.pem",
167
 
                      metavar="FILE",
168
 
                      help="Public key certificate to use")
169
 
    parser.add_option("--key", type="string", default="key.pem",
170
 
                      metavar="FILE",
171
 
                      help="Private key to use")
172
 
    parser.add_option("--ca", type="string", default="ca.pem",
173
 
                      metavar="FILE",
174
 
                      help="Certificate Authority certificate to use")
175
 
    parser.add_option("--crl", type="string", default="crl.pem",
176
 
                      metavar="FILE",
177
 
                      help="Certificate Revokation List to use")
178
 
    parser.add_option("-p", "--port", type="int", default=49001,
 
680
                      metavar="IF", help="Bind to interface IF")
 
681
    parser.add_option("-a", "--address", type="string",
 
682
                      help="Address to listen for requests on")
 
683
    parser.add_option("-p", "--port", type="int",
179
684
                      help="Port number to receive requests on")
180
 
    parser.add_option("--dh", type="int", metavar="BITS",
181
 
                      help="DH group to use")
182
 
    parser.add_option("-t", "--timeout", type="string", # Parsed later
183
 
                      default="15m",
184
 
                      help="Amount of downtime allowed for clients")
185
 
    parser.add_option("--interval", type="string", # Parsed later
186
 
                      default="5m",
187
 
                      help="How often to check that a client is up")
188
685
    parser.add_option("--check", action="store_true", default=False,
189
686
                      help="Run self-test")
 
687
    parser.add_option("--debug", action="store_true",
 
688
                      help="Debug mode; run in foreground and log to"
 
689
                      " terminal")
 
690
    parser.add_option("--priority", type="string", help="GnuTLS"
 
691
                      " priority string (see GnuTLS documentation)")
 
692
    parser.add_option("--servicename", type="string", metavar="NAME",
 
693
                      help="Zeroconf service name")
 
694
    parser.add_option("--configdir", type="string",
 
695
                      default="/etc/mandos", metavar="DIR",
 
696
                      help="Directory to search for configuration"
 
697
                      " files")
190
698
    (options, args) = parser.parse_args()
191
 
 
 
699
    
192
700
    if options.check:
193
701
        import doctest
194
702
        doctest.testmod()
195
703
        sys.exit()
196
704
    
197
 
    # Parse the time arguments
198
 
    try:
199
 
        options.timeout = string_to_delta(options.timeout)
200
 
    except ValueError:
201
 
        parser.error("option --timeout: Unparseable time")
202
 
    
203
 
    try:
204
 
        options.interval = string_to_delta(options.interval)
205
 
    except ValueError:
206
 
        parser.error("option --interval: Unparseable time")
207
 
    
208
 
    cert = gnutls.crypto.X509Certificate(open(options.cert).read())
209
 
    key = gnutls.crypto.X509PrivateKey(open(options.key).read())
210
 
    ca = gnutls.crypto.X509Certificate(open(options.ca).read())
211
 
    crl = gnutls.crypto.X509CRL(open(options.crl).read())
212
 
    cred = gnutls.connection.X509Credentials(cert, key, [ca], [crl])
213
 
    
214
 
    # Parse config file
215
 
    defaults = {}
216
 
    client_config_object = ConfigParser.SafeConfigParser(defaults)
217
 
    client_config_object.read("mandos-clients.conf")
218
 
    clients = [Client(name=section, options=options,
219
 
                      **(dict(client_config_object.items(section))))
220
 
               for section in client_config_object.sections()]
221
 
    
222
 
    udp_server = IPv6_UDPServer((in6addr_any, options.port),
223
 
                                udp_handler,
224
 
                                options=options)
225
 
    
226
 
    tcp_server = IPv6_TCPServer((in6addr_any, options.port),
 
705
    # Default values for config file for server-global settings
 
706
    server_defaults = { "interface": "",
 
707
                        "address": "",
 
708
                        "port": "",
 
709
                        "debug": "False",
 
710
                        "priority":
 
711
                        "SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP",
 
712
                        "servicename": "Mandos",
 
713
                        }
 
714
    
 
715
    # Parse config file for server-global settings
 
716
    server_config = ConfigParser.SafeConfigParser(server_defaults)
 
717
    del server_defaults
 
718
    server_config.read(os.path.join(options.configdir, "mandos.conf"))
 
719
    # Convert the SafeConfigParser object to a dict
 
720
    server_settings = server_config.defaults()
 
721
    # Use getboolean on the boolean config option
 
722
    server_settings["debug"] = server_config.getboolean\
 
723
                               ("DEFAULT", "debug")
 
724
    del server_config
 
725
    
 
726
    # Override the settings from the config file with command line
 
727
    # options, if set.
 
728
    for option in ("interface", "address", "port", "debug",
 
729
                   "priority", "servicename", "configdir"):
 
730
        value = getattr(options, option)
 
731
        if value is not None:
 
732
            server_settings[option] = value
 
733
    del options
 
734
    # Now we have our good server settings in "server_settings"
 
735
    
 
736
    debug = server_settings["debug"]
 
737
    
 
738
    if not debug:
 
739
        syslogger.setLevel(logging.WARNING)
 
740
        console.setLevel(logging.WARNING)
 
741
    
 
742
    if server_settings["servicename"] != "Mandos":
 
743
        syslogger.setFormatter(logging.Formatter\
 
744
                               ('Mandos (%s): %%(levelname)s:'
 
745
                                ' %%(message)s'
 
746
                                % server_settings["servicename"]))
 
747
    
 
748
    # Parse config file with clients
 
749
    client_defaults = { "timeout": "1h",
 
750
                        "interval": "5m",
 
751
                        "checker": "fping -q -- %(host)s",
 
752
                        "host": "",
 
753
                        }
 
754
    client_config = ConfigParser.SafeConfigParser(client_defaults)
 
755
    client_config.read(os.path.join(server_settings["configdir"],
 
756
                                    "clients.conf"))
 
757
    
 
758
    global service
 
759
    service = AvahiService(name = server_settings["servicename"],
 
760
                           type = "_mandos._tcp", );
 
761
    if server_settings["interface"]:
 
762
        service.interface = if_nametoindex(server_settings["interface"])
 
763
    
 
764
    global main_loop
 
765
    global bus
 
766
    global server
 
767
    # From the Avahi example code
 
768
    DBusGMainLoop(set_as_default=True )
 
769
    main_loop = gobject.MainLoop()
 
770
    bus = dbus.SystemBus()
 
771
    server = dbus.Interface(
 
772
            bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
 
773
            avahi.DBUS_INTERFACE_SERVER )
 
774
    # End of Avahi example code
 
775
    
 
776
    clients = Set()
 
777
    def remove_from_clients(client):
 
778
        clients.remove(client)
 
779
        if not clients:
 
780
            logger.critical(u"No clients left, exiting")
 
781
            sys.exit()
 
782
    
 
783
    clients.update(Set(Client(name = section,
 
784
                              stop_hook = remove_from_clients,
 
785
                              config
 
786
                              = dict(client_config.items(section)))
 
787
                       for section in client_config.sections()))
 
788
    if not clients:
 
789
        logger.critical(u"No clients defined")
 
790
        sys.exit(1)
 
791
    
 
792
    if debug:
 
793
        # Redirect stdin so all checkers get /dev/null
 
794
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
 
795
        os.dup2(null, sys.stdin.fileno())
 
796
        if null > 2:
 
797
            os.close(null)
 
798
    else:
 
799
        # No console logging
 
800
        logger.removeHandler(console)
 
801
        # Close all input and output, do double fork, etc.
 
802
        daemon()
 
803
    
 
804
    pidfilename = "/var/run/mandos/mandos.pid"
 
805
    pid = os.getpid()
 
806
    try:
 
807
        pidfile = open(pidfilename, "w")
 
808
        pidfile.write(str(pid) + "\n")
 
809
        pidfile.close()
 
810
        del pidfile
 
811
    except IOError, err:
 
812
        logger.error(u"Could not write %s file with PID %d",
 
813
                     pidfilename, os.getpid())
 
814
    
 
815
    def cleanup():
 
816
        "Cleanup function; run on exit"
 
817
        global group
 
818
        # From the Avahi example code
 
819
        if not group is None:
 
820
            group.Free()
 
821
            group = None
 
822
        # End of Avahi example code
 
823
        
 
824
        while clients:
 
825
            client = clients.pop()
 
826
            client.stop_hook = None
 
827
            client.stop()
 
828
    
 
829
    atexit.register(cleanup)
 
830
    
 
831
    if not debug:
 
832
        signal.signal(signal.SIGINT, signal.SIG_IGN)
 
833
    signal.signal(signal.SIGHUP, lambda signum, frame: sys.exit())
 
834
    signal.signal(signal.SIGTERM, lambda signum, frame: sys.exit())
 
835
    
 
836
    for client in clients:
 
837
        client.start()
 
838
    
 
839
    tcp_server = IPv6_TCPServer((server_settings["address"],
 
840
                                 server_settings["port"]),
227
841
                                tcp_handler,
228
 
                                options=options,
229
 
                                clients=clients,
230
 
                                credentials=cred)
231
 
    
232
 
    while True:
233
 
        in_, out, err = select.select((udp_server,
234
 
                                       tcp_server), (), ())
235
 
        for server in in_:
236
 
            server.handle_request()
237
 
 
238
 
 
239
 
if __name__ == "__main__":
 
842
                                settings=server_settings,
 
843
                                clients=clients)
 
844
    # Find out what port we got
 
845
    service.port = tcp_server.socket.getsockname()[1]
 
846
    logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
 
847
                u" scope_id %d" % tcp_server.socket.getsockname())
 
848
    
 
849
    #service.interface = tcp_server.socket.getsockname()[3]
 
850
    
 
851
    try:
 
852
        # From the Avahi example code
 
853
        server.connect_to_signal("StateChanged", server_state_changed)
 
854
        try:
 
855
            server_state_changed(server.GetState())
 
856
        except dbus.exceptions.DBusException, error:
 
857
            logger.critical(u"DBusException: %s", error)
 
858
            sys.exit(1)
 
859
        # End of Avahi example code
 
860
        
 
861
        gobject.io_add_watch(tcp_server.fileno(), gobject.IO_IN,
 
862
                             lambda *args, **kwargs:
 
863
                             tcp_server.handle_request\
 
864
                             (*args[2:], **kwargs) or True)
 
865
        
 
866
        logger.debug(u"Starting main loop")
 
867
        main_loop_started = True
 
868
        main_loop.run()
 
869
    except AvahiError, error:
 
870
        logger.critical(u"AvahiError: %s" + unicode(error))
 
871
        sys.exit(1)
 
872
    except KeyboardInterrupt:
 
873
        if debug:
 
874
            print
 
875
 
 
876
if __name__ == '__main__':
240
877
    main()
241