summaryrefslogtreecommitdiff
path: root/src/leap/bitmask/vpn/privilege.py
blob: 2576877a18bd7e623c79b94dd0fae45ca7aa0f78 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
# -*- 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

from leap.bitmask.util import STANDALONE, here

log = Logger()


def install_helpers():
    cmd = 'bitmask_helpers install'
    if STANDALONE:
        binary_path = os.path.join(here(), "bitmask")
        cmd = "%s %s" % (binary_path, cmd)

    # TODO  check if the command has succeeded, and display error
    # if failed
    commands.getoutput('pkexec ' + cmd)


def uninstall_helpers():
    cmd = 'bitmask_helpers uninstall'
    if STANDALONE:
        binary_path = os.path.join(here(), "bitmask")
        cmd = "%s %s" % (binary_path, cmd)

    # TODO  check if the command has succeeded, and display error
    # if failed
    commands.getoutput('pkexec ' + cmd)


class NoPolkitAuthAgentAvailable(Exception):
    message = 'No polkit authentication agent available. Please run one.'


class NoPkexecAvailable(Exception):
    message = 'Could not find pkexec in the system'


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.
        log.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 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)
                if not pkexec_possibilities:
                    raise Exception("We couldn't find pkexec")
                return pkexec_possibilities
            else:
                log.warn('No polkit auth agent found. pkexec ' +
                         'will use its own auth agent.')
                raise NoPolkitAuthAgentAvailable()
        else:
            log.warn('System has no pkexec')
            raise NoPkexecAvailable()

    @classmethod
    def launch(self):
        """
        Tries to launch policykit
        """
        env = None
        if 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.
            log.debug('Trying to launch polkit agent')
            subprocess.call(["python -m leap.bitmask.util.polkit_agent"],
                            shell=True, env=env)
        except Exception:
            log.failure('Error while launching vpn')

    @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