#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2014-2016 Wojtek Porczyk <woju@invisiblethingslab.com>
# Copyright (C) 2016 Marek Marczykowski <marmarek@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/>.
#
''' A disposable vm implementation '''
import copy
import qubes.vm.qubesvm
import qubes.vm.appvm
import qubes.config
def _setter_template(self, prop, value):
if not getattr(value, 'template_for_dispvms', False):
raise qubes.exc.QubesPropertyValueError(self, prop, value,
'template for DispVM must have template_for_dispvms=True')
return value
[docs]
class DispVM(qubes.vm.qubesvm.QubesVM):
'''Disposable VM'''
template = qubes.VMProperty('template',
load_stage=4,
setter=_setter_template,
doc='AppVM, on which this DispVM is based.')
dispid = qubes.property('dispid', type=int, write_once=True,
clone=False,
doc='''Internal, persistent identifier of particular DispVM.''')
auto_cleanup = qubes.property('auto_cleanup', type=bool, default=False,
doc='automatically remove this VM upon shutdown')
include_in_backups = qubes.property('include_in_backups', type=bool,
default=(lambda self: not self.auto_cleanup),
doc='If this domain is to be included in default backup.')
default_dispvm = qubes.VMProperty('default_dispvm',
load_stage=4,
allow_none=True,
default=(lambda self: self.template),
doc='Default VM to be used as Disposable VM for service calls.')
default_volume_config = {
'root': {
'name': 'root',
'snap_on_start': True,
'save_on_stop': False,
'rw': True,
'source': None,
},
'private': {
'name': 'private',
'snap_on_start': True,
'save_on_stop': False,
'rw': True,
'source': None,
},
'volatile': {
'name': 'volatile',
'snap_on_start': False,
'save_on_stop': False,
'rw': True,
'size': qubes.config.defaults['root_img_size'] +
qubes.config.defaults['private_img_size'],
},
'kernel': {
'name': 'kernel',
'snap_on_start': False,
'save_on_stop': False,
'rw': False,
},
}
def __init__(self, app, xml, *args, **kwargs):
self.volume_config = copy.deepcopy(self.default_volume_config)
template = kwargs.get('template', None)
if xml is None:
assert template is not None
if not getattr(template, 'template_for_dispvms', False):
raise qubes.exc.QubesValueError(
'template for DispVM ({}) needs to be an AppVM with '
'template_for_dispvms=True'.format(template.name))
if 'dispid' not in kwargs:
kwargs['dispid'] = app.domains.get_new_unused_dispid()
if 'name' not in kwargs:
kwargs['name'] = 'disp' + str(kwargs['dispid'])
if template is not None:
# template is only passed if the AppVM is created, in other cases we
# don't need to patch the volume_config because the config is
# coming from XML, already as we need it
for name, config in template.volume_config.items():
# in case the template vm has more volumes add them to own
# config
if name not in self.volume_config:
self.volume_config[name] = config.copy()
if 'vid' in self.volume_config[name]:
del self.volume_config[name]['vid']
else:
# if volume exists, use its live config, since some settings
# can be changed and volume_config isn't updated
config = template.volumes[name].config
# copy pool setting from base AppVM; root and private would
# be in the same pool anyway (because of snap_on_start),
# but not volatile, which could be surprising
if 'pool' not in self.volume_config[name] \
and 'pool' in config:
self.volume_config[name]['pool'] = config['pool']
# copy rw setting from the base AppVM too
if 'rw' in config:
self.volume_config[name]['rw'] = config['rw']
# copy ephemeral setting from the base AppVM too, but only
# if non-default value is used
if 'ephemeral' not in self.volume_config[name] \
and 'ephemeral' in config:
self.volume_config[name]['ephemeral'] = \
config['ephemeral']
super().__init__(app, xml, *args, **kwargs)
if xml is None:
# by default inherit properties from the DispVM template
proplist = [prop.__name__ for prop in template.property_list()
if prop.clone and prop.__name__ not in ['template']]
# Do not overwrite properties that have already been set to a
# non-default value.
self_props = [prop.__name__ for prop in self.property_list()
if self.property_is_default(prop)]
self.clone_properties(template, set(proplist).intersection(
self_props))
self.firewall.clone(template.firewall)
self.features.update(template.features)
self.tags.update(template.tags)
[docs]
@qubes.events.handler('domain-load')
def on_domain_loaded(self, event):
''' When domain is loaded assert that this vm has a template.
''' # pylint: disable=unused-argument
assert self.template
[docs]
@qubes.events.handler('property-pre-reset:template')
def on_property_pre_reset_template(self, event, name, oldvalue=None):
'''Forbid deleting template of VM
''' # pylint: disable=unused-argument
raise qubes.exc.QubesValueError('Cannot unset template')
[docs]
@qubes.events.handler('property-pre-set:template')
def on_property_pre_set_template(self, event, name, newvalue,
oldvalue=None):
'''Forbid changing template of running VM
''' # pylint: disable=unused-argument
if not self.is_halted():
raise qubes.exc.QubesVMNotHaltedError(self,
'Cannot change template while qube is running')
[docs]
@qubes.events.handler('property-set:template')
def on_property_set_template(self, event, name, newvalue, oldvalue=None):
''' Adjust root (and possibly other snap_on_start=True) volume
on template change.
''' # pylint: disable=unused-argument
qubes.vm.appvm.template_changed_update_storage(self)
[docs]
@qubes.events.handler('domain-shutdown')
async def on_domain_shutdown(self, _event, **_kwargs): # pylint: disable=invalid-overridden-method
await self._auto_cleanup()
async def _auto_cleanup(self):
'''Do auto cleanup if enabled'''
if self.auto_cleanup and self in self.app.domains:
del self.app.domains[self]
await self.remove_from_disk()
self.app.save()
[docs]
@classmethod
async def from_appvm(cls, appvm, **kwargs):
'''Create a new instance from given AppVM
:param qubes.vm.appvm.AppVM appvm: template from which the VM should \
be created
:returns: new disposable vm
*kwargs* are passed to the newly created VM
>>> import qubes.vm.dispvm.DispVM
>>> dispvm = qubes.vm.dispvm.DispVM.from_appvm(appvm).start()
>>> dispvm.run_service('qubes.VMShell', input='firefox')
>>> dispvm.cleanup()
This method modifies :file:`qubes.xml` file.
The qube returned is not started.
'''
if not getattr(appvm, 'template_for_dispvms', False):
raise qubes.exc.QubesException(
'Refusing to create DispVM out of this AppVM, because '
'template_for_dispvms=False')
app = appvm.app
dispvm = app.add_new_vm(
cls,
template=appvm,
auto_cleanup=True,
**kwargs)
await dispvm.create_on_disk()
app.save()
return dispvm
[docs]
async def cleanup(self):
'''Clean up after the DispVM
This stops the disposable qube and removes it from the store.
This method modifies :file:`qubes.xml` file.
'''
try:
await self.kill()
except qubes.exc.QubesVMNotStartedError:
pass
# if auto_cleanup is set, this will be done automatically
if not self.auto_cleanup:
del self.app.domains[self]
await self.remove_from_disk()
self.app.save()
[docs]
async def start(self, **kwargs):
# pylint: disable=arguments-differ
try:
# sanity check, if template_for_dispvm got changed in the meantime
if not self.template.template_for_dispvms:
raise qubes.exc.QubesException(
'template for DispVM ({}) needs to have '
'template_for_dispvms=True'.format(self.template.name))
await super().start(**kwargs)
except:
# Cleanup also on failed startup
await self._auto_cleanup()
raise
[docs]
def create_qdb_entries(self):
super().create_qdb_entries()
self.untrusted_qdb.write('/qubes-vm-persistence', 'none')