Certificate revocation, with broadcast of CRL

TODO

@@ -20,3 +20,8 @@
 
 - registry: add '--home PATH' command line option so that / display an HTML
   page from PATH (use new str.format for templating)
+
+- Better UI to revoke certificates, for example with a HTML form.
+  Currently, one have to forge the URL manually. Examples:
+    wget -O /dev/null http://re6st.example.com/revoke?cn_or_serial=123
+    wget -O /dev/null http://re6st.example.com/revoke?cn_or_serial=4/16

re6st/cache.py

@@ -4,6 +4,8 @@ from . import utils, version, x509
 
 class Cache(object):
 
+    crl = ()
+
     def __init__(self, db_path, registry, cert, db_size=200):
         self._prefix = cert.prefix
         self._db_size = db_size
@@ -40,6 +42,7 @@ class Cache(object):
                 # when it tried to send us new parameters.
                 or self._prefix == self.registry_prefix):
                 self.updateConfig()
+        self.next_renew = cert.maybeRenew(self._registry, self.crl)
         if version.protocol < self.min_protocol:
             logging.critical("Your version of re6stnet is too old."
                              " Please update.")
@@ -64,7 +67,11 @@ class Cache(object):
         cls = self.__class__
         logging.debug("Loading network parameters:")
         for k, v in config:
-            hasattr(cls, k) or setattr(self, k, v)
+            if k == 'crl':
+                v = set(json.loads(v))
+            elif hasattr(cls, k):
+                continue
+            setattr(self, k, v)
             logging.debug("- %s: %r", k, v)
 
     def updateConfig(self):
@@ -77,6 +84,7 @@ class Cache(object):
             config = dict((str(k), v.decode('base64') if k in base64 else
                                    str(v) if type(v) is unicode else v)
                           for k, v in config.iteritems())
+            config['crl'] = json.dumps(config['crl'])
         except socket.error, e:
             logging.warning(e)
             return

re6st/ovpn-client

@@ -9,7 +9,7 @@ if script_type == 'up':
     os.execlp('ip', 'ip', 'link', 'set', os.environ['dev'], 'up',
               'mtu', os.environ['tun_mtu'])
 
-# Write into pipe external ip address received
-import time
-os.write(int(sys.argv[1]), "%s %s %s %s\n" % (script_type,
-  os.environ['common_name'], time.time(), os.environ['OPENVPN_external_ip']))
+if script_type == 'route-up':
+    import time
+    os.write(int(sys.argv[1]), repr((os.environ['common_name'], time.time(),
+        int(os.environ['tls_serial_0']), os.environ['OPENVPN_external_ip'])))

re6st/ovpn-server

@@ -2,15 +2,16 @@
 import os, sys
 
 script_type = os.environ['script_type']
-external_ip = lambda: os.getenv('trusted_ip') or os.environ['trusted_ip6']
+external_ip = os.getenv('trusted_ip') or os.environ['trusted_ip6']
+
+# Write into pipe connect/disconnect events
+fd = int(sys.argv[1])
+os.write(fd, repr((script_type, (os.environ['common_name'], os.environ['dev'],
+                   int(os.environ['tls_serial_0']), external_ip))))
 
 if script_type == 'client-connect':
+    if os.read(fd, 1) == '\0':
+        sys.exit(1)
     # Send client its external ip address
     with open(sys.argv[2], 'w') as f:
-        f.write('push "setenv-safe external_ip %s"\n' % external_ip())
-
-# Write into pipe connect/disconnect events
-arg1 = sys.argv[1]
-if arg1 != 'None':
-    os.write(int(arg1), '%s %s %s\n' % (
-        script_type, os.environ['common_name'], external_ip()))
+        f.write('push "setenv-safe external_ip %s"\n' % external_ip)

re6st/plib.py

@@ -25,10 +25,8 @@ def openvpn(iface, encrypt, *args, **kw):
 
 ovpn_link_mtu_dict = {'udp': 1481, 'udp6': 1450}
 
-def server(iface, max_clients, dh_path, pipe_fd, port, proto, encrypt, *args, **kw):
-    client_script = '%s %s' % (ovpn_server, pipe_fd)
-    if pipe_fd is not None:
-        args = ('--client-disconnect', client_script) + args
+def server(iface, max_clients, dh_path, fd, port, proto, encrypt, *args, **kw):
+    client_script = '%s %s' % (ovpn_server, fd)
     try:
         args = ('--link-mtu', str(ovpn_link_mtu_dict[proto]),
                 # mtu-disc ignored for udp6 due to a bug in OpenVPN
@@ -39,6 +37,7 @@ def server(iface, max_clients, dh_path, pipe_fd, port, proto, encrypt, *args, **
         '--tls-server',
         '--mode', 'server',
         '--client-connect', client_script,
+        '--client-disconnect', client_script,
         '--dh', dh_path,
         '--max-clients', str(max_clients),
         '--port', str(port),

re6st/registry.py

@@ -25,6 +25,7 @@ from collections import defaultdict, deque
 from datetime import datetime
 from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler
 from email.mime.text import MIMEText
+from operator import itemgetter
 from OpenSSL import crypto
 from urllib import splittype, splithost, splitport, urlencode
 from . import ctl, tunnel, utils, version, x509
@@ -71,6 +72,20 @@ class RegistryServer(object):
                 "email TEXT",
                 "cert TEXT"):
             self.db.execute("INSERT INTO cert VALUES ('',null,null)")
+        if utils.sqliteCreateTable(self.db, "crl",
+                "serial INTEGER PRIMARY KEY NOT NULL",
+                # Expiration date of revoked certificate.
+                # TODO: purge rows with dates in the past.
+                "date INTEGER NOT NULL"):
+            # Revoke certificates produced by previous version.
+            # They all have serial 0.
+            try:
+                date = max(x509.notAfter(x[0]) for x in self.iterCert())
+            except ValueError:
+                pass
+            else:
+                if time.time() < date:
+                    self.db.execute("INSERT INTO crl VALUES (0,?)", (date,))
 
         self.cert = x509.Cert(self.config.ca, self.config.key)
         # Get vpn network prefix
@@ -97,9 +112,11 @@ class RegistryServer(object):
         self.db.execute("INSERT OR REPLACE INTO config VALUES (?, ?)",
                         name_value)
 
-    def updateNetworkConfig(self):
+    def updateNetworkConfig(self, _it0=itemgetter(0)):
         kw = {
             'babel_default': 'max-rtt-penalty 5000 rtt-max 500 rtt-decay 125',
+            'crl': map(_it0, self.db.execute(
+                "SELECT serial FROM crl ORDER BY serial")),
             'protocol': version.protocol,
             'registry_prefix': self.prefix,
         }
@@ -220,7 +237,7 @@ class RegistryServer(object):
     def handle_request(self, request, method, kw,
                        _localhost=('127.0.0.1', '::1')):
         m = getattr(self, method)
-        if method in ('versions', 'topology'):
+        if method in ('revoke', 'versions', 'topology'):
             x_forwarded_for = request.headers.get('X-Forwarded-For')
             if request.client_address[0] not in _localhost or \
                x_forwarded_for and x_forwarded_for not in _localhost:
@@ -393,15 +410,16 @@ class RegistryServer(object):
     @rpc
     def renewCertificate(self, cn):
         with self.lock:
-            with self.db:
+            with self.db as db:
                 pem = self.getCert(cn)
                 cert = crypto.load_certificate(crypto.FILETYPE_PEM, pem)
                 if x509.notAfter(cert) - RENEW_PERIOD < time.time():
                     not_after = None
-                elif cert.get_serial_number():
-                    return pem
-                else:
+                elif db.execute("SELECT count(*) FROM crl WHERE serial=?",
+                                (cert.get_serial_number(),)).fetchone()[0]:
                     not_after = cert.get_notAfter()
+                else:
+                    return pem
                 return self.createCertificate(cn,
                     cert.get_subject(), cert.get_pubkey(), not_after)
 
@@ -452,6 +470,29 @@ class RegistryServer(object):
         logging.info("Sending bootstrap peer: %s", msg)
         return x509.encrypt(cert, msg)
 
+    @rpc
+    def revoke(self, cn_or_serial):
+        with self.lock:
+          with self.db:
+            q = self.db.execute
+            try:
+                serial = int(cn_or_serial)
+            except ValueError:
+                prefix = utils.binFromSubnet(cn_or_serial)
+                cert = self.getCert(prefix)
+                q("UPDATE cert SET email=null, cert=null WHERE prefix=?",
+                  (prefix,))
+                cert = crypto.load_certificate(crypto.FILETYPE_PEM, cert)
+                serial = cert.get_serial_number()
+                self.sessions.pop(prefix, None)
+            else:
+                cert, = (cert for cert, prefix, email in self.iterCert()
+                              if cert.get_serial_number() == serial)
+            not_after = x509.notAfter(cert)
+            if time.time() < not_after:
+                q("INSERT INTO crl VALUES (?,?)", (serial, not_after))
+                self.updateNetworkConfig()
+
     @rpc
     def versions(self):
         with self.peers_lock:

re6st/tunnel.py

-import errno, logging, os, random, socket, subprocess, time, weakref
+import errno, logging, os, random, socket, subprocess, struct, time, weakref
 from collections import defaultdict, deque
 from bisect import bisect, insort
 from OpenSSL import crypto
@@ -40,6 +40,7 @@ class MultiGatewayManager(dict):
 class Connection(object):
 
     _retry = 0
+    serial = None
     time = float('inf')
 
     def __init__(self, tunnel_manager, address_list, iface, prefix):
@@ -69,15 +70,19 @@ class Connection(object):
             '--connect-retry-max', '3', '--tls-exit',
             '--remap-usr1', 'SIGTERM',
             '--ping-exit', str(tm.timeout),
-            '--route-up', '%s %u' % (plib.ovpn_client, tm.write_pipe),
+            '--route-up', '%s %u' % (plib.ovpn_client, tm.write_sock.fileno()),
             *tm.ovpn_args)
         tm.resetTunnelRefresh()
         self._retry += 1
 
-    def connected(self):
+    def connected(self, serial):
+        cache = self.tunnel_manager.cache
+        if serial in cache.crl:
+            self.tunnel_manager._kill(self._prefix)
+            return
+        self.serial = serial
         i = self._retry - 1
         self._retry = None
-        cache = self.tunnel_manager.cache
         if i:
             cache.addPeer(self._prefix, ','.join(self.address_list[i]), True)
         else:
@@ -167,14 +172,14 @@ class BaseTunnelManager(object):
 
     _forward = None
 
-    def __init__(self, cache, cert, cert_renew, address=()):
+    def __init__(self, cache, cert, address=()):
         self.cert = cert
         self._network = cert.network
         self._prefix = cert.prefix
         self.cache = cache
         self._connecting = set()
         self._connection_dict = {}
-        self._served = set()
+        self._served = defaultdict(dict)
         self._version = cache.version
 
         address_dict = defaultdict(list)
@@ -190,9 +195,9 @@ class BaseTunnelManager(object):
         self.sock.bind(('::', PORT))
 
         p = x509.Peer(self._prefix)
-        p.stop_date = cert_renew
+        p.stop_date = cache.next_renew
         self._peers = [p]
-        self._timeouts = [(cert_renew, self.invalidatePeers)]
+        self._timeouts = [(p.stop_date, self.invalidatePeers)]
 
     def select(self, r, w, t):
         r[self.sock] = self.handlePeerEvent
@@ -307,6 +312,9 @@ class BaseTunnelManager(object):
                 cert = self.cert.loadVerify(msg,
                     True, crypto.FILETYPE_ASN1)
                 stop_date = x509.notAfter(cert)
+                serial = cert.get_serial_number()
+                if serial in self.cache.crl:
+                    raise ValueError("revoked")
             except (x509.VerifyError, ValueError), e:
                 logging.debug('ignored invalid certificate from %r (%s)',
                               address, e.args[-1])
@@ -320,6 +328,7 @@ class BaseTunnelManager(object):
                 peer = x509.Peer(p)
                 insort(self._peers, peer)
             peer.cert = cert
+            peer.serial = serial
             peer.stop_date = stop_date
             self.selectTimeout(stop_date, self.invalidatePeers, False)
             if seqno:
@@ -398,7 +407,7 @@ class BaseTunnelManager(object):
         raise utils.ReexecException(
             "Restart with new network parameters")
 
-    def broadcastVersion(self):
+    def _newVersion(self):
         pass
 
     def newVersion(self):
@@ -410,32 +419,77 @@ class BaseTunnelManager(object):
         logging.info("changed: %r", changed)
         self.selectTimeout(None, self.newVersion)
         self._version = self.cache.version
-        self.broadcastVersion()
+        self._newVersion()
         self.cache.warnProtocol()
-        if not self.NEED_RESTART.isdisjoint(changed) or \
-           version.protocol < self.cache.min_protocol:
+        crl = self.cache.crl
+        for i in reversed([i for i, peer in enumerate(self._peers)
+                             if peer.serial in crl]):
+            del self._peers[i]
+        if self.cert.cert.get_serial_number() in crl:
+            raise utils.ReexecException("Our certificate has just been revoked."
+                " Let's try to renew it.")
+        if (not self.NEED_RESTART.isdisjoint(changed)
+            or version.protocol < self.cache.min_protocol
+            # TODO: With --management, we could kill clients without restarting.
+            or not all(crl.isdisjoint(serials.itervalues())
+                       for serials in self._served.itervalues())):
             # Wait at least 1 second to broadcast new version to neighbours.
             # If re6stnet is too old, don't abort now, because a new version
             # may have been installed without restart.
             self.selectTimeout(time.time() + 1 + self.cache.delay_restart,
                                self._restart)
 
+    def handleServerEvent(self, sock):
+        event, args = eval(sock.recv(65536))
+        logging.debug("%s%r", event, args)
+        r = getattr(self, '_ovpn_' + event.replace('-', '_'))(*args)
+        if r is not None:
+            sock.send(chr(r))
+
+    def _ovpn_client_connect(self, common_name, iface, serial, trusted_ip):
+        if serial in self.cache.crl:
+            return False
+        prefix = utils.binFromSubnet(common_name)
+        self._served[prefix][iface] = serial
+        if isinstance(self, TunnelManager): # XXX
+            if self._gateway_manager is not None:
+                self._gateway_manager.add(trusted_ip, False)
+            if prefix in self._connection_dict and self._prefix < prefix:
+                self._kill(prefix)
+                self.cache.connecting(prefix, 0)
+        return True
+
+    def _ovpn_client_disconnect(self, common_name, iface, serial, trusted_ip):
+        prefix = utils.binFromSubnet(common_name)
+        serials = self._served.get(prefix)
+        try:
+            del serials[iface]
+        except (KeyError, TypeError):
+            logging.exception("ovpn_client_disconnect%r",
+                              (common_name, iface, serial, trusted_ip))
+            return
+        if not serials:
+            del self._served[prefix]
+        if isinstance(self, TunnelManager): # XXX
+            self._abortTunnelKiller(prefix, iface)
+            if self._gateway_manager is not None:
+                self._gateway_manager.remove(trusted_ip)
+
 
 class TunnelManager(BaseTunnelManager):
 
     NEED_RESTART = BaseTunnelManager.NEED_RESTART.union((
         'client_count', 'max_clients', 'tunnel_refresh'))
 
-    def __init__(self, control_socket, cache, cert, cert_renew, openvpn_args,
+    def __init__(self, control_socket, cache, cert, openvpn_args,
                  timeout, client_count, iface_list, address, ip_changed,
                  remote_gateway, disable_proto, neighbour_list=()):
-        super(TunnelManager, self).__init__(cache, cert, cert_renew, address)
+        super(TunnelManager, self).__init__(cache, cert, address)
         self.ctl = ctl.Babel(control_socket, weakref.proxy(self), self._network)
         self.ovpn_args = openvpn_args
         self.timeout = timeout
-        # Create and open read_only pipe to get server events
-        r, self.write_pipe = os.pipe()
-        self._read_pipe = os.fdopen(r)
+        self._read_sock, self.write_sock = socket.socketpair(
+            socket.AF_UNIX, socket.SOCK_DGRAM)
         self._disconnected = 0
         self._distant_peers = []
         self._iface_to_prefix = {}
@@ -497,7 +551,7 @@ class TunnelManager(BaseTunnelManager):
 
     def select(self, r, w, t):
         super(TunnelManager, self).select(r, w, t)
-        r[self._read_pipe] = self.handleTunnelEvent
+        r[self._read_sock] = self.handleClientEvent
         if self._next_refresh:
             t.append((self._next_refresh, self.refresh))
         self.ctl.select(r, w, t)
@@ -572,11 +626,13 @@ class TunnelManager(BaseTunnelManager):
             prefix = min(peer_set, key=self._tunnelScore)
             self._killing[prefix] = TunnelKiller(prefix, self, True)
 
-    def _abortTunnelKiller(self, prefix):
+    def _abortTunnelKiller(self, prefix, iface=None):
         tunnel_killer = self._killing.get(prefix)
         if tunnel_killer:
             if tunnel_killer.state:
-                tunnel_killer.abort()
+                if not iface or \
+                   iface == self.ctl.interfaces[tunnel_killer.ifindex]:
+                    tunnel_killer.abort()
             else:
                 del self._killing[prefix]
 
@@ -719,42 +775,15 @@ class TunnelManager(BaseTunnelManager):
         for prefix in self._connection_dict.keys():
             self._kill(prefix)
 
-    def handleTunnelEvent(self):
-        try:
-            msg = self._read_pipe.readline().rstrip()
-            args = msg.split()
-            m = getattr(self, '_ovpn_' + args.pop(0).replace('-', '_'))
-        except (AttributeError, ValueError):
-            logging.warning("Unknown message received from OpenVPN: %s", msg)
-        else:
-            logging.debug(msg)
-            m(*args)
-
-    def _ovpn_client_connect(self, common_name, trusted_ip):
-        prefix = utils.binFromSubnet(common_name)
-        self._served.add(prefix)
-        if self._gateway_manager is not None:
-            self._gateway_manager.add(trusted_ip, False)
-        if prefix in self._connection_dict and self._prefix < prefix:
-            self._kill(prefix)
-            self.cache.connecting(prefix, 0)
-
-    def _ovpn_client_disconnect(self, common_name, trusted_ip):
-        prefix = utils.binFromSubnet(common_name)
-        try:
-            self._served.remove(prefix)
-        except KeyError:
-            return
-        self._abortTunnelKiller(prefix)
-        if self._gateway_manager is not None:
-            self._gateway_manager.remove(trusted_ip)
-
-    def _ovpn_route_up(self, common_name, time, ip):
+    def handleClientEvent(self):
+        msg = self._read_sock.recv(65536)
+        logging.debug("route_up%s", msg)
+        common_name, time, serial, ip = eval(msg)
         prefix = utils.binFromSubnet(common_name)
         c = self._connection_dict.get(prefix)
         if c and c.time < float(time):
             try:
-                c.connected()
+                c.connected(serial)
             except (KeyError, TypeError), e:
                 logging.error("%s (route_up %s)", e, common_name)
         else:
@@ -765,7 +794,7 @@ class TunnelManager(BaseTunnelManager):
             if address:
                 self._address[family] = utils.dump_address(address)
 
-    def broadcastVersion(self):
+    def _newVersion(self):
         for prefix in self.ctl.neighbours:
             if prefix:
                 peer = self._getPeer(prefix)
@@ -774,3 +803,6 @@ class TunnelManager(BaseTunnelManager):
                 elif (peer.version < self._version and
                       self.sendto(prefix, '\0' + self._version)):
                     peer.version = self._version
+        for prefix, c in self._connection_dict.items():
+            if c.serial in self.cache.crl:
+                self._kill(prefix)

re6st/x509.py

@@ -42,10 +42,12 @@ def encrypt(cert, data):
 def fingerprint(cert, alg='sha1'):
     return hashlib.new(alg, crypto.dump_certificate(crypto.FILETYPE_ASN1, cert))
 
-def maybe_renew(path, cert, info, renew):
+def maybe_renew(path, cert, info, renew, force=False):
     from .registry import RENEW_PERIOD
     while True:
-        if cert.get_serial_number():
+        if force:
+            force = False
+        else:
             next_renew = notAfter(cert) - RENEW_PERIOD
             if time.time() < next_renew:
                 return cert, next_renew
@@ -110,11 +112,10 @@ class Cert(object):
                 '--cert', self.cert_path,
                 '--key', self.key_path)
 
-    def maybeRenew(self, registry):
-        from .registry import RegistryClient
-        registry = RegistryClient(registry, self)
+    def maybeRenew(self, registry, crl):
         self.cert, next_renew = maybe_renew(self.cert_path, self.cert,
-              "Certificate", lambda: registry.renewCertificate(self.prefix))
+              "Certificate", lambda: registry.renewCertificate(self.prefix),
+              self.cert.get_serial_number() in crl)
         self.ca, ca_renew = maybe_renew(self.ca_path, self.ca,
               "CA Certificate", registry.getCa)
         return min(next_renew, ca_renew)
@@ -181,6 +182,7 @@ class Peer(object):
     """
     _hello = _last = 0
     _key = newHmacSecret()
+    serial = None
     stop_date = float('inf')
     version = ''
 

re6stnet

@@ -2,6 +2,7 @@
 import atexit, errno, logging, os, shutil, signal
 import socket, subprocess, sys, time, threading
 from collections import deque
+from functools import partial
 from re6st import plib, tunnel, utils, version, x509
 from re6st.cache import Cache
 from re6st.utils import exit, ReexecException
@@ -130,7 +131,6 @@ def main():
     exit.signal(0, signal.SIGINT, signal.SIGTERM)
     exit.signal(-1, signal.SIGHUP, signal.SIGUSR2)
 
-    next_renew = cert.maybeRenew(config.registry)
     cache = Cache(db_path, config.registry, cert)
     network = cert.network
 
@@ -249,14 +249,12 @@ def main():
         control_socket = os.path.join(config.run, 'babeld.sock')
         if config.client_count and not config.client:
             tunnel_manager = tunnel.TunnelManager(control_socket,
-                cache, cert, next_renew, config.openvpn_args, timeout,
+                cache, cert, config.openvpn_args, timeout,
                 config.client_count, config.iface_list, address, ip_changed,
                 remote_gateway, config.disable_proto, config.neighbour)
             tunnel_interfaces += tunnel_manager.new_iface_list
-            write_pipe = tunnel_manager.write_pipe
         else:
-            write_pipe = None
-            tunnel_manager = tunnel.BaseTunnelManager(cache, cert, next_renew)
+            tunnel_manager = tunnel.BaseTunnelManager(cache, cert)
         cleanup.append(tunnel_manager.sock.close)
 
         try:
@@ -275,6 +273,7 @@ def main():
             #      an public IP so Babel must be changed to set a source
             #      address on routes it installs.
             ip('addrlabel', 'prefix', my_network, 'label', '99')
+            R = {}
             # prepare persistent interfaces
             if config.client:
                 address_list = [x for x in utils.parse_address(config.client)
@@ -288,9 +287,13 @@ def main():
             elif server_tunnels:
                 required('dh')
                 for iface, (port, proto) in server_tunnels.iteritems():
+                    r, x = socket.socketpair(socket.AF_UNIX, socket.SOCK_DGRAM)
                     cleanup.append(plib.server(iface, config.max_clients,
-                        config.dh, write_pipe, port, proto, cache.encrypt,
-                        '--ping-exit', str(timeout), *config.openvpn_args).stop)
+                        config.dh, x.fileno(), port, proto, cache.encrypt,
+                        '--ping-exit', str(timeout), *config.openvpn_args,
+                        preexec_fn=r.close).stop)
+                    R[r] = partial(tunnel_manager.handleServerEvent, r)
+                    x.close()
 
             ip('addr', my_ip, 'dev', config.main_interface)
             if_rt = ['ip', '-6', 'route', 'del',
@@ -371,7 +374,7 @@ def main():
             select_list = [forwarder.select] if forwarder else []
             select_list += tunnel_manager.select, utils.select
             while True:
-                args = {}, {}, []
+                args = R.copy(), {}, []
                 for s in select_list:
                     s(*args)
         finally: