Merge remote-tracking branch 'meskio/feature/6040_email_firewall' into develop

8 files changed, 403 insertions, 125 deletions

diff --git a/changes/feature-6040-email-firewall b/changes/feature-6040-email-firewall
new file mode 100644
index 00000000..5ef70d28
--- /dev/null
+++ b/changes/feature-6040-email-firewall
@@ -0,0 +1 @@
+- Add email firewall blocking other users to access bitmask imap & smtp. Closes #6040
diff --git a/docs/man/bitmask-root.1.rst b/docs/man/bitmask-root.1.rst
index c18cc4d6..dde303ae 100644
--- a/docs/man/bitmask-root.1.rst
+++ b/docs/man/bitmask-root.1.rst
@@ -49,6 +49,19 @@ firewall
 
 **stop**               Stops the firewall.
 
+**isup**               Check if the firewall is up.
+
+
+fw-email
+---------
+
+**start** UID          Starts the email firewall. UID is the user name or unix
+                       id that will have access to the email.
+
+**stop**               Stops the email firewall.
+
+**isup**               Check if the email firewall is up.
+
 version
 --------
 
diff --git a/pkg/linux/bitmask-root b/pkg/linux/bitmask-root
index fa7fc92a..ba262a2c 100755
--- a/pkg/linux/bitmask-root
+++ b/pkg/linux/bitmask-root
@@ -25,6 +25,8 @@ USAGE:
   bitmask-root firewall start [restart] GATEWAY1 GATEWAY2 ...
   bitmask-root openvpn stop
   bitmask-root openvpn start CONFIG1 CONFIG1 ...
+  bitmask-root fw-email stop
+  bitmask-root fw-email start uid
 
 All actions return exit code 0 for success, non-zero otherwise.
 
@@ -55,6 +57,11 @@ NAMESERVER = "10.42.0.1"
 BITMASK_CHAIN = "bitmask"
 BITMASK_CHAIN_NAT_OUT = "bitmask"
 BITMASK_CHAIN_NAT_POST = "bitmask_postrouting"
+BITMASK_CHAIN_EMAIL = "bitmask_email"
+BITMASK_CHAIN_EMAIL_OUT = "bitmask_email_output"
+LOCAL_INTERFACE = "lo"
+IMAP_PORT = "1984"
+SMTP_PORT = "2013"
 
 IP = "/bin/ip"
 IPTABLES = "/sbin/iptables"
@@ -101,7 +108,8 @@ PARAM_FORMATS = {
         "^[a-zA-Z0-9_\.\@][a-zA-Z0-9_\-\.\@]*\$?$", s),  # IEEE Std 1003.1-2001
     "FILE": lambda s: os.path.isfile(s),
     "DIR": lambda s: os.path.isdir(os.path.split(s)[0]),
-    "UNIXSOCKET": lambda s: s == "unix"
+    "UNIXSOCKET": lambda s: s == "unix",
+    "UID": lambda s: re.match("^[a-zA-Z0-9]+$", s)
 }
 
 
@@ -740,6 +748,119 @@ def firewall_stop():
                         "Please try `firewall stop` again.")
 
 
+def fw_email_start(args):
+    """
+    Bring up the email firewall.
+
+    :param args: the user uid of the bitmask process
+    :type args: list
+    """
+    # add custom chain "bitmask_email" to front of INPUT chain
+    if not ipv4_chain_exists(BITMASK_CHAIN_EMAIL):
+        ip4tables("--new-chain", BITMASK_CHAIN_EMAIL)
+    if not ipv6_chain_exists(BITMASK_CHAIN_EMAIL):
+        ip6tables("--new-chain", BITMASK_CHAIN_EMAIL)
+    iptables("--insert", "INPUT", "--jump", BITMASK_CHAIN_EMAIL)
+
+    # add custom chain "bitmask_email_output" to front of OUTPUT chain
+    if not ipv4_chain_exists(BITMASK_CHAIN_EMAIL_OUT):
+        ip4tables("--new-chain", BITMASK_CHAIN_EMAIL_OUT)
+    if not ipv6_chain_exists(BITMASK_CHAIN_EMAIL_OUT):
+        ip6tables("--new-chain", BITMASK_CHAIN_EMAIL_OUT)
+    iptables("--insert", "OUTPUT", "--jump", BITMASK_CHAIN_EMAIL_OUT)
+
+    # Disable the access to imap and smtp from outside
+    iptables("--append", BITMASK_CHAIN_EMAIL,
+             "--in-interface", LOCAL_INTERFACE, "--protocol", "tcp",
+             "--dport", IMAP_PORT, "--jump", "ACCEPT")
+    iptables("--append", BITMASK_CHAIN_EMAIL,
+             "--in-interface", LOCAL_INTERFACE, "--protocol", "tcp",
+             "--dport", SMTP_PORT, "--jump", "ACCEPT")
+    iptables("--append", BITMASK_CHAIN_EMAIL,
+             "--protocol", "tcp", "--dport", IMAP_PORT, "--jump", "REJECT")
+    iptables("--append", BITMASK_CHAIN_EMAIL,
+             "--protocol", "tcp", "--dport", SMTP_PORT, "--jump", "REJECT")
+
+    if not args or not PARAM_FORMATS["UID"](args[0]):
+        raise Exception("No uid given")
+    uid = args[0]
+
+    # Only the unix 'uid' have access to the email imap and smtp ports
+    iptables("--append", BITMASK_CHAIN_EMAIL_OUT,
+             "--out-interface", LOCAL_INTERFACE,
+             "--match", "owner", "--uid-owner", uid, "--protocol", "tcp",
+             "--dport", IMAP_PORT, "--jump", "ACCEPT")
+    iptables("--append", BITMASK_CHAIN_EMAIL_OUT,
+             "--out-interface", LOCAL_INTERFACE,
+             "--match", "owner", "--uid-owner", uid, "--protocol", "tcp",
+             "--dport", SMTP_PORT, "--jump", "ACCEPT")
+    iptables("--append", BITMASK_CHAIN_EMAIL_OUT,
+             "--out-interface", LOCAL_INTERFACE,
+             "--protocol", "tcp", "--dport", IMAP_PORT, "--jump", "REJECT")
+    iptables("--append", BITMASK_CHAIN_EMAIL_OUT,
+             "--out-interface", LOCAL_INTERFACE,
+             "--protocol", "tcp", "--dport", SMTP_PORT, "--jump", "REJECT")
+
+
+def fw_email_stop():
+    """
+    Stop the email firewall.
+    """
+    ok = True
+
+    try:
+        iptables("--delete", "INPUT", "--jump", BITMASK_CHAIN_EMAIL,
+                 throw=True)
+    except subprocess.CalledProcessError as exc:
+        debug("INFO: not able to remove bitmask email firewall from INPUT "
+              "chain (maybe it is already removed?)", exc)
+        ok = False
+
+    try:
+        iptables("--delete", "OUTPUT", "--jump", BITMASK_CHAIN_EMAIL_OUT,
+                 throw=True)
+    except subprocess.CalledProcessError as exc:
+        debug("INFO: not able to remove bitmask email firewall from OUTPUT "
+              "chain (maybe it is already removed?)", exc)
+        ok = False
+
+    try:
+        ip4tables("--flush", BITMASK_CHAIN_EMAIL, throw=True)
+        ip4tables("--delete-chain", BITMASK_CHAIN_EMAIL, throw=True)
+    except subprocess.CalledProcessError as exc:
+        debug("INFO: not able to flush and delete bitmask ipv4 email firewall "
+              "chain (maybe it is already destroyed?)", exc)
+        ok = False
+
+    try:
+        ip6tables("--flush", BITMASK_CHAIN_EMAIL, throw=True)
+        ip6tables("--delete-chain", BITMASK_CHAIN_EMAIL, throw=True)
+    except subprocess.CalledProcessError as exc:
+        debug("INFO: not able to flush and delete bitmask ipv6 email firewall "
+              "chain (maybe it is already destroyed?)", exc)
+        ok = False
+
+    try:
+        ip4tables("--flush", BITMASK_CHAIN_EMAIL_OUT, throw=True)
+        ip4tables("--delete-chain", BITMASK_CHAIN_EMAIL_OUT, throw=True)
+    except subprocess.CalledProcessError as exc:
+        debug("INFO: not able to flush and delete bitmask ipv4 email firewall "
+              "chain (maybe it is already destroyed?)", exc)
+        ok = False
+
+    try:
+        ip6tables("--flush", BITMASK_CHAIN_EMAIL_OUT, throw=True)
+        ip6tables("--delete-chain", BITMASK_CHAIN_EMAIL_OUT, throw=True)
+    except subprocess.CalledProcessError as exc:
+        debug("INFO: not able to flush and delete bitmask ipv6 email firewall "
+              "chain (maybe it is already destroyed?)", exc)
+        ok = False
+
+    if not (ok or ipv4_chain_exists or ipv6_chain_exists):
+        raise Exception("email firewall might still be left up. "
+                        "Please try `fw-email stop` again.")
+
+
 #
 # MAIN
 #
@@ -793,6 +914,26 @@ def main():
             else:
                 bail("INFO: bitmask firewall is down")
 
+        elif command == "fw-email_start":
+            try:
+                fw_email_start(args)
+            except Exception as ex:
+                if not is_restart:
+                    fw_email_stop()
+                bail("ERROR: could not start email firewall", ex)
+
+        elif command == "fw-email_stop":
+            try:
+                fw_email_stop()
+            except Exception as ex:
+                bail("ERROR: could not stop email firewall", ex)
+
+        elif command == "fw-email_isup":
+            if ipv4_chain_exists(BITMASK_CHAIN_EMAIL):
+                log("%s: INFO: bitmask email firewall is up" % (SCRIPT,))
+            else:
+                bail("INFO: bitmask email firewall is down")
+
         else:
             bail("ERROR: No such command")
     else:
diff --git a/src/leap/bitmask/gui/mainwindow.py b/src/leap/bitmask/gui/mainwindow.py
index 8127c1f6..9c5045ec 100644
--- a/src/leap/bitmask/gui/mainwindow.py
+++ b/src/leap/bitmask/gui/mainwindow.py
@@ -271,9 +271,7 @@ class MainWindow(QtGui.QMainWindow):
         # Services signals/slots connection
         self.new_updates.connect(self._react_to_new_updates)
 
-        # XXX should connect to mail_conductor.start_mail_service instead
-        self.soledad_ready.connect(self._start_smtp_bootstrapping)
-        self.soledad_ready.connect(self._start_imap_service)
+        self.soledad_ready.connect(self._start_mail_service)
         # ################################ end Qt Signals connection ########
 
         init_platform()
@@ -1563,37 +1561,12 @@ class MainWindow(QtGui.QMainWindow):
         self.soledad_ready.emit()
 
     ###################################################################
-    # Service control methods: smtp
-
-    @QtCore.Slot()
-    def _start_smtp_bootstrapping(self):
-        """
-        TRIGGERS:
-            self.soledad_ready
-        """
-        if flags.OFFLINE is True:
-            logger.debug("not starting smtp in offline mode")
-            return
-
-        if self._provides_mx_and_enabled():
-            self._mail_conductor.start_smtp_service(download_if_needed=True)
-
-    ###################################################################
-    # Service control methods: imap
-
+    # Service control methods: mail
     @QtCore.Slot()
-    def _start_imap_service(self):
-        """
-        TRIGGERS:
-            self.soledad_ready
-        """
-        # TODO in the OFFLINE mode we should also modify the  rules
-        # in the mail state machine so it shows that imap is active
-        # (but not smtp since it's not yet ready for offline use)
+    def _start_mail_service(self):
         if self._provides_mx_and_enabled() or flags.OFFLINE:
-            self._mail_conductor.start_imap_service()
-
-    # end service control methods (imap)
+            self._mail_conductor.start_mail_service(download_if_needed=True,
+                                                    offline=flags.OFFLINE)
 
     ###################################################################
     # Service control methods: eip
@@ -1902,8 +1875,7 @@ class MainWindow(QtGui.QMainWindow):
         self._leap_signaler.eip_stopped.connect(eip_stopped)
 
         logger.debug('Stopping mail services')
-        self._backend.imap_stop_service()
-        self._backend.smtp_stop_service()
+        self._mail_conductor.stop_mail_services()
 
         if self._logged_user is not None:
             logger.debug("Doing logout")
diff --git a/src/leap/bitmask/services/eip/linuxvpnlauncher.py b/src/leap/bitmask/services/eip/linuxvpnlauncher.py
index b6e47f25..a3ab408b 100644
--- a/src/leap/bitmask/services/eip/linuxvpnlauncher.py
+++ b/src/leap/bitmask/services/eip/linuxvpnlauncher.py
@@ -20,17 +20,15 @@ Linux VPN launcher implementation.
 import commands
 import logging
 import os
-import subprocess
 import sys
-import time
 
 from leap.bitmask.config import flags
 from leap.bitmask.util.privilege_policies import LinuxPolicyChecker
-from leap.common.files import which
+from leap.bitmask.util.privilege_policies import NoPolkitAuthAgentAvailable
+from leap.bitmask.util.privilege_policies import NoPkexecAvailable
 from leap.bitmask.services.eip.vpnlauncher import VPNLauncher
 from leap.bitmask.services.eip.vpnlauncher import VPNLauncherException
 from leap.bitmask.util import get_path_prefix, force_eval
-from leap.common.check import leap_assert
 from leap.bitmask.util import first
 
 logger = logging.getLogger(__name__)
@@ -46,66 +44,11 @@ class EIPNoPkexecAvailable(VPNLauncherException):
     pass
 
 
-def _is_pkexec_in_system():
-    """
-    Checks the existence of the pkexec binary in system.
-    """
-    pkexec_path = which('pkexec')
-    if len(pkexec_path) == 0:
-        return False
-    return True
-
-
-def _is_auth_agent_running():
-    """
-    Checks if a polkit daemon is running.
-
-    :return: True if it's running, False if it's not.
-    :rtype: boolean
-    """
-    # Note that gnome-shell does not uses a separate process for the
-    # polkit-agent, it uses a polkit-agent within its own process so we can't
-    # ps-grep a polkit process, we can ps-grep gnome-shell itself.
-
-    # the [x] thing is to avoid grep match itself
-    polkit_options = [
-        'ps aux | grep "polkit-[g]nome-authentication-agent-1"',
-        'ps aux | grep "polkit-[k]de-authentication-agent-1"',
-        'ps aux | grep "polkit-[m]ate-authentication-agent-1"',
-        'ps aux | grep "[l]xpolkit"',
-        'ps aux | grep "[g]nome-shell"',
-        'ps aux | grep "[f]ingerprint-polkit-agent"',
-    ]
-    is_running = [commands.getoutput(cmd) for cmd in polkit_options]
-
-    return any(is_running)
-
-
-def _try_to_launch_agent():
-    """
-    Tries to launch a polkit daemon.
-    """
-    env = None
-    if flags.STANDALONE:
-        env = {"PYTHONPATH": os.path.abspath('../../../../lib/')}
-    try:
-        # We need to quote the command because subprocess call
-        # will do "sh -c 'foo'", so if we do not quoute it we'll end
-        # up with a invocation to the python interpreter. And that
-        # is bad.
-        logger.debug("Trying to launch polkit agent")
-        subprocess.call(["python -m leap.bitmask.util.polkit_agent"],
-                        shell=True, env=env)
-    except Exception as exc:
-        logger.exception(exc)
-
-
 SYSTEM_CONFIG = "/etc/leap"
 leapfile = lambda f: "%s/%s" % (SYSTEM_CONFIG, f)
 
 
 class LinuxVPNLauncher(VPNLauncher):
-    PKEXEC_BIN = 'pkexec'
 
     # The following classes depend on force_eval to be called against
     # the classes, to get the evaluation of the standalone flag on runtine.
@@ -130,36 +73,6 @@ class LinuxVPNLauncher(VPNLauncher):
     OTHER_FILES = (POLKIT_PATH, BITMASK_ROOT, OPENVPN_BIN_PATH)
 
     @classmethod
-    def maybe_pkexec(kls):
-        """
-        Checks whether pkexec is available in the system, and
-        returns the path if found.
-
-        Might raise:
-            EIPNoPkexecAvailable,
-            EIPNoPolkitAuthAgentAvailable.
-
-        :returns: a list of the paths where pkexec is to be found
-        :rtype: list
-        """
-        if _is_pkexec_in_system():
-            if not _is_auth_agent_running():
-                _try_to_launch_agent()
-                time.sleep(2)
-            if _is_auth_agent_running():
-                pkexec_possibilities = which(kls.PKEXEC_BIN)
-                leap_assert(len(pkexec_possibilities) > 0,
-                            "We couldn't find pkexec")
-                return pkexec_possibilities
-            else:
-                logger.warning("No polkit auth agent found. pkexec " +
-                               "will use its own auth agent.")
-                raise EIPNoPolkitAuthAgentAvailable()
-        else:
-            logger.warning("System has no pkexec")
-            raise EIPNoPkexecAvailable()
-
-    @classmethod
     def get_vpn_command(kls, eipconfig, providerconfig, socket_host,
                         socket_port="unix", openvpn_verb=1):
         """
@@ -194,7 +107,13 @@ class LinuxVPNLauncher(VPNLauncher):
         command.insert(1, "openvpn")
         command.insert(2, "start")
 
-        pkexec = kls.maybe_pkexec()
+        policyChecker = LinuxPolicyChecker()
+        try:
+            pkexec = policyChecker.maybe_pkexec()
+        except NoPolkitAuthAgentAvailable:
+            raise EIPNoPolkitAuthAgentAvailable()
+        except NoPkexecAvailable:
+            raise EIPNoPkexecAvailable()
         if pkexec:
             command.insert(0, first(pkexec))
 
diff --git a/src/leap/bitmask/services/mail/conductor.py b/src/leap/bitmask/services/mail/conductor.py
index 5e85368f..416aff34 100644
--- a/src/leap/bitmask/services/mail/conductor.py
+++ b/src/leap/bitmask/services/mail/conductor.py
@@ -22,6 +22,7 @@ import logging
 from leap.bitmask.config import flags
 from leap.bitmask.gui import statemachines
 from leap.bitmask.services.mail import connection as mail_connection
+from leap.bitmask.services.mail.emailfirewall import get_email_firewall
 
 from leap.common.events import events_pb2 as leap_events
 from leap.common.events import register as leap_register
@@ -211,6 +212,11 @@ class MailConductor(IMAPControl, SMTPControl):
         self._mail_connection = mail_connection.MailConnection()
 
         self._userid = None
+        try:
+            self._firewall = get_email_firewall()
+        except NotImplementedError:
+            self._firewall = None
+            logger.info("Email firewall is not implemented in this platform")
 
     @property
     def userid(self):
@@ -247,12 +253,25 @@ class MailConductor(IMAPControl, SMTPControl):
         self._smtp_machine = smtp
         self._smtp_machine.start()
 
+    def start_mail_service(self, download_if_needed=False, offline=False):
+        """
+        Start the IMAP and SMTP servcies.
+        """
+        if self._firewall is not None:
+            self._firewall.start()
+        if not offline:
+            logger.debug("not starting smtp in offline mode")
+            self.start_smtp_service(download_if_needed=download_if_needed)
+        self.start_imap_service()
+
     def stop_mail_services(self):
         """
         Stop the IMAP and SMTP services.
         """
         self.stop_imap_service()
         self.stop_smtp_service()
+        if self._firewall is not None:
+            self._firewall.stop()
 
     def connect_mail_signals(self, widget):
         """
diff --git a/src/leap/bitmask/services/mail/emailfirewall.py b/src/leap/bitmask/services/mail/emailfirewall.py
new file mode 100644
index 00000000..2cd2ec31
--- /dev/null
+++ b/src/leap/bitmask/services/mail/emailfirewall.py
@@ -0,0 +1,115 @@
+# -*- coding: utf-8 -*-
+# emailfirewall.py
+# Copyright (C) 2014 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Email firewall implementation.
+"""
+
+import os
+import subprocess
+
+from abc import ABCMeta, abstractmethod
+
+from leap.bitmask.config import flags
+from leap.bitmask.platform_init import IS_LINUX
+from leap.bitmask.util import first, force_eval
+from leap.bitmask.util.privilege_policies import LinuxPolicyChecker
+from leap.common.check import leap_assert
+
+
+def get_email_firewall():
+    """
+    Return the email firewall handler for the current platform.
+    """
+    if not (IS_LINUX):
+        error_msg = "Email firewall not implemented for this platform."
+        raise NotImplementedError(error_msg)
+
+    firewall = None
+    if IS_LINUX:
+        firewall = LinuxEmailFirewall
+
+    leap_assert(firewall is not None)
+
+    return firewall()
+
+
+class EmailFirewall(object):
+    """
+    Abstract email firwall class
+    """
+    __metaclass__ = ABCMeta
+
+    @abstractmethod
+    def start(self):
+        """
+        Start email firewall
+        """
+        return False
+
+    @abstractmethod
+    def stop(self):
+        """
+        Stop email firewall
+        """
+        return False
+
+
+class EmailFirewallException(Exception):
+    pass
+
+
+class LinuxEmailFirewall(EmailFirewall):
+
+    class BITMASK_ROOT(object):
+        def __call__(self):
+            return ("/usr/local/sbin/bitmask-root" if flags.STANDALONE else
+                    "/usr/sbin/bitmask-root")
+
+    def start(self):
+        uid = str(os.getuid())
+        return True if self._run(["start", uid]) is 0 else False
+
+    def stop(self):
+        return True if self._run(["stop"]) is 0 else False
+
+    def _run(self, cmd):
+        """
+        Run an email firewall command with bitmask-root
+
+        Might raise:
+            NoPkexecAvailable,
+            NoPolkitAuthAgentAvailable,
+
+        :param cmd: command to send to bitmask-root fw-email
+        :type cmd: [str]
+        :returns: exit code of bitmask-root
+        :rtype: int
+        """
+        command = []
+
+        policyChecker = LinuxPolicyChecker()
+        pkexec = policyChecker.maybe_pkexec()
+        if pkexec:
+            command.append(first(pkexec))
+
+        command.append(force_eval(self.BITMASK_ROOT))
+        command.append("fw-email")
+        command += cmd
+
+        # XXX: will be nice to use twisted ProcessProtocol instead of
+        #      subprocess to avoid blocking until it finish
+        return subprocess.call(command)
diff --git a/src/leap/bitmask/util/privilege_policies.py b/src/leap/bitmask/util/privilege_policies.py
index f894d73b..2016e67b 100644
--- a/src/leap/bitmask/util/privilege_policies.py
+++ b/src/leap/bitmask/util/privilege_policies.py
@@ -18,17 +18,30 @@
 Helpers to determine if the needed policies for privilege escalation
 are operative under this client run.
 """
+import commands
 import logging
 import os
+import subprocess
 import platform
+import time
 
 from abc import ABCMeta, abstractmethod
 
 from leap.bitmask.config import flags
+from leap.common.check import leap_assert
+from leap.common.files import which
 
 logger = logging.getLogger(__name__)
 
 
+class NoPolkitAuthAgentAvailable(Exception):
+    pass
+
+
+class NoPkexecAvailable(Exception):
+    pass
+
+
 def is_missing_policy_permissions():
     """
     Returns True if we do not have implemented a policy checker for this
@@ -75,6 +88,7 @@ class LinuxPolicyChecker(PolicyChecker):
                          "se.leap.bitmask.policy")
     LINUX_POLKIT_FILE_BUNDLE = ("/usr/share/polkit-1/actions/"
                                 "se.leap.bitmask.bundle.policy")
+    PKEXEC_BIN = 'pkexec'
 
     @classmethod
     def get_polkit_path(self):
@@ -97,3 +111,87 @@ class LinuxPolicyChecker(PolicyChecker):
         """
         path = self.get_polkit_path()
         return not os.path.isfile(path)
+
+    @classmethod
+    def maybe_pkexec(self):
+        """
+        Checks whether pkexec is available in the system, and
+        returns the path if found.
+
+        Might raise:
+            NoPkexecAvailable,
+            NoPolkitAuthAgentAvailable.
+
+        :returns: a list of the paths where pkexec is to be found
+        :rtype: list
+        """
+        if self._is_pkexec_in_system():
+            if not self.is_up():
+                self.launch()
+                time.sleep(2)
+            if self.is_up():
+                pkexec_possibilities = which(self.PKEXEC_BIN)
+                leap_assert(len(pkexec_possibilities) > 0,
+                            "We couldn't find pkexec")
+                return pkexec_possibilities
+            else:
+                logger.warning("No polkit auth agent found. pkexec " +
+                               "will use its own auth agent.")
+                raise NoPolkitAuthAgentAvailable()
+        else:
+            logger.warning("System has no pkexec")
+            raise NoPkexecAvailable()
+
+    @classmethod
+    def launch(self):
+        """
+        Tries to launch policykit
+        """
+        env = None
+        if flags.STANDALONE:
+            env = {"PYTHONPATH": os.path.abspath('../../../../lib/')}
+        try:
+            # We need to quote the command because subprocess call
+            # will do "sh -c 'foo'", so if we do not quoute it we'll end
+            # up with a invocation to the python interpreter. And that
+            # is bad.
+            logger.debug("Trying to launch polkit agent")
+            subprocess.call(["python -m leap.bitmask.util.polkit_agent"],
+                            shell=True, env=env)
+        except Exception as exc:
+            logger.exception(exc)
+
+    @classmethod
+    def is_up(self):
+        """
+        Checks if a polkit daemon is running.
+
+        :return: True if it's running, False if it's not.
+        :rtype: boolean
+        """
+        # Note that gnome-shell does not uses a separate process for the
+        # polkit-agent, it uses a polkit-agent within its own process so we
+        # can't ps-grep a polkit process, we can ps-grep gnome-shell itself.
+
+        # the [x] thing is to avoid grep match itself
+        polkit_options = [
+            'ps aux | grep "polkit-[g]nome-authentication-agent-1"',
+            'ps aux | grep "polkit-[k]de-authentication-agent-1"',
+            'ps aux | grep "polkit-[m]ate-authentication-agent-1"',
+            'ps aux | grep "[l]xpolkit"',
+            'ps aux | grep "[g]nome-shell"',
+            'ps aux | grep "[f]ingerprint-polkit-agent"',
+        ]
+        is_running = [commands.getoutput(cmd) for cmd in polkit_options]
+
+        return any(is_running)
+
+    @classmethod
+    def _is_pkexec_in_system(self):
+        """
+        Checks the existence of the pkexec binary in system.
+        """
+        pkexec_path = which('pkexec')
+        if len(pkexec_path) == 0:
+            return False
+        return True