core-admin/qubes/ext/admin.py

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# -*- encoding: utf8 -*-
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2017 Wojtek Porczyk <woju@invisiblethingslab.com>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, see <https://www.gnu.org/licenses/>.
import qubes.api
import qubes.api.internal
import qubes.ext
import qubes.vm.adminvm
from qrexec.policy import utils, parser
class JustEvaluateAskResolution(parser.AskResolution):
async def execute(self, caller_ident):
pass
class JustEvaluateAllowResolution(parser.AllowResolution):
async def execute(self, caller_ident):
pass
class AdminExtension(qubes.ext.Extension):
def __init__(self):
super(AdminExtension, self).__init__()
# during tests, __init__() of the extension can be called multiple
# times, because there are multiple Qubes() object instances
if not hasattr(self, 'policy_cache'):
self.policy_cache = utils.PolicyCache(lazy_load=True)
self.policy_cache.initialize_watcher()
# pylint: disable=too-few-public-methods
@qubes.ext.handler(
'admin-permission:admin.vm.tag.Set',
'admin-permission:admin.vm.tag.Remove')
def on_tag_set_or_remove(self, vm, event, arg, **kwargs):
'''Forbid changing specific tags'''
# pylint: disable=no-self-use,unused-argument
if arg.startswith('created-by-') and \
not isinstance(vm, qubes.vm.adminvm.AdminVM):
raise qubes.api.PermissionDenied(
'changing this tag is prohibited by {}.{}'.format(
__name__, type(self).__name__))
# TODO create that tag here (need to figure out how to pass mgmtvm name)
@qubes.ext.handler('admin-permission:admin.vm.List')
def admin_vm_list(self, vm, event, arg, **kwargs):
'''When called with target 'dom0' (aka "get full list"), exclude domains
that the caller don't have permission to list
'''
# pylint: disable=unused-argument
if vm.klass == 'AdminVM':
# dom0 can always list everything
return None
policy = self.policy_cache.get_policy()
system_info = qubes.api.internal.get_system_info(vm.app)
def filter_vms(dest_vm):
request = parser.Request(
'admin.vm.List',
'+' + arg,
vm.name,
dest_vm.name,
system_info=system_info,
ask_resolution_type=JustEvaluateAskResolution,
allow_resolution_type=JustEvaluateAllowResolution)
try:
resolution = policy.evaluate(request)
# do not consider 'ask' as allow here,
# this needs to be not interactive
return isinstance(resolution, parser.AllowResolution)
except parser.AccessDenied:
return False
return (filter_vms,)
@qubes.ext.handler('admin-permission:admin.Events')
def admin_events(self, vm, event, arg, **kwargs):
'''When called with target 'dom0' (aka "get all events"),
exclude domains that the caller don't have permission to receive
events about
'''
# pylint: disable=unused-argument
if vm.klass == 'AdminVM':
# dom0 can always list everything
return None
def filter_events(event):
subject, event, kwargs = event
try:
dest = subject.name
except AttributeError:
# domain-add and similar events fired on the Qubes() object
if 'vm' in kwargs:
dest = kwargs['vm'].name
else:
dest = '@adminvm'
policy = self.policy_cache.get_policy()
# TODO: cache system_info (based on last qubes.xml write time?)
system_info = qubes.api.internal.get_system_info(vm.app)
request = parser.Request(
'admin.Events',
'+' + event.replace(':', '_'),
vm.name,
dest,
system_info=system_info,
ask_resolution_type=JustEvaluateAskResolution,
allow_resolution_type=JustEvaluateAllowResolution)
try:
resolution = policy.evaluate(request)
# do not consider 'ask' as allow here,
# this needs to be not interactive
return isinstance(resolution, parser.AllowResolution)
except parser.AccessDenied:
return False
return (filter_events,)
@qubes.ext.handler('qubes-close', system=True)
def on_qubes_close(self, app, event, **kwargs):
"""Unregister policy file watches on app.close()."""
# pylint: disable=unused-argument
if hasattr(self, 'policy_cache'):
self.policy_cache.cleanup()
del self.policy_cache
@qubes.ext.handler('domain-tag-add:created-by-*')
def on_tag_add(self, vm, event, tag, **kwargs):
'''Add extra tags based on creators 'tag-created-vm-with' feature'''
# pylint: disable=unused-argument,no-self-use
created_by = vm.app.domains[tag.partition('created-by-')[2]]
tag_with = created_by.features.get('tag-created-vm-with', '')
for tag_with_single in tag_with.split():
vm.tags.add(tag_with_single)