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Diffstat (limited to 'src/leap/bitmask/vpn/privilege.py')
| -rw-r--r-- | src/leap/bitmask/vpn/privilege.py | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/leap/bitmask/vpn/privilege.py b/src/leap/bitmask/vpn/privilege.py new file mode 100644 index 00000000..e8ed5576 --- /dev/null +++ b/src/leap/bitmask/vpn/privilege.py @@ -0,0 +1,210 @@ +# -*- coding: utf-8 -*- +# privilege_policies.py +# Copyright (C) 2013 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/>. + +""" +Helpers to determine if the needed policies for privilege escalation +are operative under this client run. +""" + +import commands +import os +import subprocess +import platform +import time + +from abc import ABCMeta, abstractmethod + +from twisted.logger import Logger +from twisted.python.procutils import which + +logger = Logger() + + +flags_STANDALONE = False + + +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 + platform, or if the policy checker exists but it cannot find the + appropriate policy mechanisms in place. + + :rtype: bool + """ + _system = platform.system() + platform_checker = _system + "PolicyChecker" + policy_checker = globals().get(platform_checker, None) + if not policy_checker: + # it is true that we miss permission to escalate + # privileges without asking for password each time. + logger.debug("we could not find a policy checker implementation " + "for %s" % (_system,)) + return True + return policy_checker().is_missing_policy_permissions() + + +class PolicyChecker: + """ + Abstract PolicyChecker class + """ + + __metaclass__ = ABCMeta + + @abstractmethod + def is_missing_policy_permissions(self): + """ + Returns True if we could not find any policy mechanisms that + are defined to be in used for this particular platform. + + :rtype: bool + """ + return True + + +class LinuxPolicyChecker(PolicyChecker): + """ + PolicyChecker for Linux + """ + LINUX_POLKIT_FILE = ("/usr/share/polkit-1/actions/" + "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): + """ + Returns the polkit file path. + + :rtype: str + """ + return (self.LINUX_POLKIT_FILE_BUNDLE if flags_STANDALONE + else self.LINUX_POLKIT_FILE) + + def is_missing_policy_permissions(self): + # FIXME this name is quite confusing, it does not have anything to do + # with file permissions. + """ + Returns True if we could not find the appropriate policykit file + in place + + :rtype: bool + """ + 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") + if not pkexec_possibilities: + logger.error("We couldn't find pkexec") + raise Exception("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: + # This allows us to send to subprocess the environment configs that + # works for the standalone bundle (like the PYTHONPATH) + env = dict(os.environ) + # The LD_LIBRARY_PATH is set on the launcher but not forwarded to + # subprocess unless we do so explicitly. + env["LD_LIBRARY_PATH"] = 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 "[l]xsession"', + 'ps aux | grep "[g]nome-shell"', + 'ps aux | grep "[f]ingerprint-polkit-agent"', + 'ps aux | grep "[x]fce-polkit"', + ] + 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 |