Source code for qubes.vm.mix.net

#
# The Qubes OS Project, https://www.qubes-os.org/
#
# Copyright (C) 2010-2016  Joanna Rutkowska <[email protected]>
# Copyright (C) 2013-2016  Marek Marczykowski-Górecki
#                              <[email protected]>
# Copyright (C) 2014-2016  Wojtek Porczyk <[email protected]>
#
# 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/>.
#

''' This module contains the NetVMMixin '''
import ipaddress
import os
import re

import libvirt  # pylint: disable=import-error
import qubes
import qubes.config
import qubes.events
import qubes.firewall
import qubes.exc

def _setter_mac(self, prop, value):
    ''' Helper for setting the MAC address '''
    # pylint: disable=unused-argument
    if not isinstance(value, str):
        raise ValueError('MAC address must be a string')
    value = value.lower()
    if re.match(r"^([0-9a-f][0-9a-f]:){5}[0-9a-f][0-9a-f]$", value) is None:
        raise ValueError('Invalid MAC address value')
    return value


def _default_ip(self):
    if not self.is_networked():
        return None
    if self.netvm is not None:
        return self.netvm.get_ip_for_vm(self)  # pylint: disable=no-member

    return self.get_ip_for_vm(self)


def _default_ip6(self):
    if not self.is_networked():
        return None
    if not self.features.check_with_netvm('ipv6', False):
        return None
    if self.netvm is not None:
        return self.netvm.get_ip6_for_vm(self)  # pylint: disable=no-member

    return self.get_ip6_for_vm(self)


def _setter_netvm(self, prop, value):
    # pylint: disable=unused-argument
    if value is None:
        return None
    if not value.provides_network:
        raise qubes.exc.QubesValueError(
            'The {!s} qube does not provide network'.format(value))

    # skip check for netvm loops during qubes.xml loading, to avoid tricky
    # loading order
    if self.events_enabled:
        if value is self \
                or value in self.app.domains.get_vms_connected_to(self):
            raise qubes.exc.QubesValueError(
                'Loops in network are unsupported')
    return value

def _setter_provides_network(self, prop, value):
    value = qubes.property.bool(self, prop, value)
    if not value:
        if list(self.connected_vms):
            raise qubes.exc.QubesValueError(
                'The qube is still used by other qubes, change theirs '
                '\'netvm\' first')

    return value


[docs]class NetVMMixin(qubes.events.Emitter): ''' Mixin containing network functionality ''' mac = qubes.property('mac', type=str, default='00:16:3e:5e:6c:00', setter=_setter_mac, doc='MAC address of the NIC emulated inside VM') ip = qubes.property('ip', type=ipaddress.IPv4Address, default=_default_ip, doc='IP address of this domain.') ip6 = qubes.property('ip6', type=ipaddress.IPv6Address, default=_default_ip6, doc='IPv6 address of this domain.') # CORE2: swallowed uses_default_netvm netvm = qubes.VMProperty('netvm', load_stage=4, allow_none=True, default=(lambda self: self.app.default_netvm), setter=_setter_netvm, doc='''VM that provides network connection to this domain. When `None`, machine is disconnected. When absent, domain uses default NetVM.''') provides_network = qubes.property('provides_network', default=False, type=bool, setter=_setter_provides_network, doc='''If this domain can act as network provider (formerly known as NetVM or ProxyVM)''') @property def firewall_conf(self): return 'firewall.xml' # # used in networked appvms or proxyvms (netvm is not None) # @qubes.stateless_property def visible_ip(self): '''IP address of this domain as seen by the domain.''' return self.features.check_with_template('net.fake-ip', None) or \ self.ip @qubes.stateless_property def visible_ip6(self): '''IPv6 address of this domain as seen by the domain.''' return self.ip6 @qubes.stateless_property def visible_gateway(self): '''Default gateway of this domain as seen by the domain.''' return self.features.check_with_template('net.fake-gateway', None) or \ (self.netvm.gateway if self.netvm else None) @qubes.stateless_property def visible_gateway6(self): '''Default (IPv6) gateway of this domain as seen by the domain.''' if self.features.check_with_netvm('ipv6', False): return self.netvm.gateway6 if self.netvm else None return None @qubes.stateless_property def visible_netmask(self): '''Netmask as seen by the domain.''' return self.features.check_with_template('net.fake-netmask', None) or \ (self.netvm.netmask if self.netvm else None) # # used in netvms (provides_network=True) # those properties and methods are most likely accessed as vm.netvm.<prop> #
[docs] @staticmethod def get_ip_for_vm(vm): '''Get IP address for (appvm) domain connected to this (netvm) domain. ''' import qubes.vm.dispvm # pylint: disable=redefined-outer-name if isinstance(vm, qubes.vm.dispvm.DispVM): return ipaddress.IPv4Address('10.138.{}.{}'.format( (vm.dispid >> 8) & 0xff, vm.dispid & 0xff)) # VM technically can get address which ends in '.0'. This currently # does not happen, because qid < 253, but may happen in the future. return ipaddress.IPv4Address('10.137.{}.{}'.format( (vm.qid >> 8) & 0xff, vm.qid & 0xff))
[docs] @staticmethod def get_ip6_for_vm(vm): '''Get IPv6 address for (appvm) domain connected to this (netvm) domain. Default address is constructed with Qubes-specific site-local prefix, and IPv4 suffix (0xa89 is 10.137.). ''' import qubes.vm.dispvm # pylint: disable=redefined-outer-name if isinstance(vm, qubes.vm.dispvm.DispVM): return ipaddress.IPv6Address('{}::a8a:{:x}'.format( qubes.config.qubes_ipv6_prefix, vm.dispid)) return ipaddress.IPv6Address('{}::a89:{:x}'.format( qubes.config.qubes_ipv6_prefix, vm.qid))
@qubes.stateless_property def gateway(self): '''Gateway for other domains that use this domain as netvm.''' return self.visible_ip if self.provides_network else None @qubes.stateless_property def gateway6(self): '''Gateway (IPv6) for other domains that use this domain as netvm.''' if self.features.check_with_netvm('ipv6', False): return self.visible_ip6 if self.provides_network else \ None return None @property def netmask(self): '''Netmask for gateway address.''' return '255.255.255.255' if self.is_networked() else None @property def connected_vms(self): ''' Return a generator containing all domains connected to the current NetVM. ''' for vm in self.app.domains: if getattr(vm, 'netvm', None) is self: yield vm # # used in both # @property def dns(self): '''Secondary DNS server set up for this domain.''' if self.netvm is not None or self.provides_network: return ( '10.139.1.1', '10.139.1.2', ) return None def __init__(self, *args, **kwargs): self._firewall = None super(NetVMMixin, self).__init__(*args, **kwargs) @qubes.events.handler('domain-load') def on_domain_load_netvm_loop_check(self, event): # pylint: disable=unused-argument # make sure there are no netvm loops - which could cause qubesd # looping infinitely if self is self.netvm: self.log.error( 'vm \'%s\' network-connected to itself, breaking the ' 'connection', self.name) self.netvm = None elif self.netvm in self.app.domains.get_vms_connected_to(self): self.log.error( 'netvm loop detected on \'%s\', breaking the connection', self.name) self.netvm = None
[docs] @qubes.events.handler('domain-shutdown') def on_domain_shutdown(self, event, **kwargs): '''Cleanup network interfaces of connected, running VMs. This will allow re-reconnecting them cleanly later. ''' # pylint: disable=unused-argument for vm in self.connected_vms: if not vm.is_running(): continue try: vm.detach_network() except (qubes.exc.QubesException, libvirt.libvirtError): # ignore errors pass
[docs] @qubes.events.handler('domain-start') def on_domain_started(self, event, **kwargs): '''Connect this domain to its downstream domains. Also reload firewall in its netvm. This is needed when starting netvm *after* its connected domains. ''' # pylint: disable=unused-argument if self.netvm: self.netvm.reload_firewall_for_vm(self) # pylint: disable=no-member for vm in self.connected_vms: if not vm.is_running(): continue vm.log.info('Attaching network') try: vm.attach_network() except (qubes.exc.QubesException, libvirt.libvirtError): vm.log.warning('Cannot attach network', exc_info=1)
[docs] @qubes.events.handler('domain-pre-shutdown') def on_domain_pre_shutdown(self, event, force=False): ''' Checks before NetVM shutdown if any connected domains are running. If `force` is `True` tries to detach network interfaces of connected vms ''' # pylint: disable=unused-argument connected_vms = [vm for vm in self.connected_vms if vm.is_running()] if connected_vms and not force: raise qubes.exc.QubesVMError(self, 'There are other VMs connected to this VM: {}'.format( ', '.join(vm.name for vm in connected_vms)))
[docs] def attach_network(self): '''Attach network in this machine to it's netvm.''' if not self.is_running(): raise qubes.exc.QubesVMNotRunningError(self) if self.netvm is None: raise qubes.exc.QubesVMError(self, 'netvm should not be {}'.format(self.netvm)) if not self.netvm.is_running(): # pylint: disable=no-member # pylint: disable=no-member self.log.info('Starting NetVM ({0})'.format(self.netvm.name)) self.netvm.start() self.netvm.set_mapped_ip_info_for_vm(self) self.libvirt_domain.attachDevice( self.app.env.get_template('libvirt/devices/net.xml').render( vm=self))
[docs] def detach_network(self): '''Detach machine from it's netvm''' if not self.is_running(): raise qubes.exc.QubesVMNotRunningError(self) if self.netvm is None: raise qubes.exc.QubesVMError(self, 'netvm should not be {}'.format(self.netvm)) self.libvirt_domain.detachDevice( self.app.env.get_template('libvirt/devices/net.xml').render( vm=self))
[docs] def is_networked(self): '''Check whether this VM can reach network (firewall notwithstanding). :returns: :py:obj:`True` if is machine can reach network, \ :py:obj:`False` otherwise. :rtype: bool ''' if self.provides_network: return True return self.netvm is not None
[docs] def reload_firewall_for_vm(self, vm): ''' Reload the firewall rules for the vm ''' if not self.is_running(): return for addr_family in (4, 6): ip = vm.ip6 if addr_family == 6 else vm.ip if ip is None: continue base_dir = '/qubes-firewall/{}/'.format(ip) # remove old entries if any (but don't touch base empty entry - it # would trigger reload right away self.untrusted_qdb.rm(base_dir) # write new rules for key, value in vm.firewall.qdb_entries( addr_family=addr_family).items(): self.untrusted_qdb.write(base_dir + key, value) # signal its done self.untrusted_qdb.write(base_dir[:-1], '')
[docs] def set_mapped_ip_info_for_vm(self, vm): ''' Set configuration to possibly hide real IP from the VM. This needs to be done before executing 'script' (`/etc/xen/scripts/vif-route-qubes`) in network providing VM ''' # add info about remapped IPs (VM IP hidden from the VM itself) mapped_ip_base = '/mapped-ip/{}'.format(vm.ip) if vm.visible_ip: self.untrusted_qdb.write(mapped_ip_base + '/visible-ip', str(vm.visible_ip)) else: self.untrusted_qdb.rm(mapped_ip_base + '/visible-ip') if vm.visible_gateway: self.untrusted_qdb.write(mapped_ip_base + '/visible-gateway', str(vm.visible_gateway)) else: self.untrusted_qdb.rm(mapped_ip_base + '/visible-gateway')
[docs] def reload_connected_ips(self): ''' Update list of IPs possibly connected to this machine. This is used by qubes-firewall to implement anti-spoofing. ''' connected_ips = [str(vm.visible_ip) for vm in self.connected_vms if vm.visible_ip is not None] connected_ips6 = [str(vm.visible_ip6) for vm in self.connected_vms if vm.visible_ip6 is not None] self.untrusted_qdb.write( '/connected-ips', ' '.join(connected_ips)) self.untrusted_qdb.write( '/connected-ips6', ' '.join(connected_ips6))
[docs] @qubes.events.handler('property-pre-del:netvm') def on_property_pre_del_netvm(self, event, name, oldvalue=None): ''' Sets the the NetVM to default NetVM ''' # pylint: disable=unused-argument # we are changing to default netvm newvalue = type(self).netvm.get_default(self) # check for netvm loop _setter_netvm(self, type(self).netvm, newvalue) if newvalue == oldvalue: return self.fire_event('property-pre-set:netvm', pre_event=True, name='netvm', newvalue=newvalue, oldvalue=oldvalue)
[docs] @qubes.events.handler('property-del:netvm') def on_property_del_netvm(self, event, name, oldvalue=None): ''' Sets the the NetVM to default NetVM ''' # pylint: disable=unused-argument # we are changing to default netvm newvalue = self.netvm if newvalue == oldvalue: return self.fire_event('property-set:netvm', name='netvm', newvalue=newvalue, oldvalue=oldvalue)
[docs] @qubes.events.handler('property-pre-set:netvm') def on_property_pre_set_netvm(self, event, name, newvalue, oldvalue=None): ''' Run sanity checks before setting a new NetVM ''' # pylint: disable=unused-argument if newvalue is not None: if not self.app.vmm.offline_mode \ and self.is_running() and not newvalue.is_running(): raise qubes.exc.QubesVMNotStartedError(newvalue, 'Cannot dynamically attach to stopped NetVM: {!r}'.format( newvalue)) # don't check oldvalue, because it's missing if it was default if self.netvm is not None: if self.is_running(): self.detach_network()
[docs] @qubes.events.handler('property-set:netvm') def on_property_set_netvm(self, event, name, newvalue, oldvalue=None): ''' Replaces the current NetVM with a new one and fires net-domain-connect event ''' # pylint: disable=unused-argument if oldvalue is not None and oldvalue.is_running(): oldvalue.reload_connected_ips() if newvalue is None: return if newvalue.is_running(): newvalue.reload_connected_ips() if self.is_running(): # refresh IP, DNS etc self.create_qdb_entries() self.attach_network() newvalue.fire_event('net-domain-connect', vm=self)
[docs] @qubes.events.handler('net-domain-connect') def on_net_domain_connect(self, event, vm): ''' Reloads the firewall config for vm ''' # pylint: disable=unused-argument self.reload_firewall_for_vm(vm)
[docs] @qubes.events.handler('domain-qdb-create') def on_domain_qdb_create(self, event): ''' Fills the QubesDB with firewall entries. ''' # pylint: disable=unused-argument # Keep the following in sync with on_firewall_changed. self.reload_connected_ips() for vm in self.connected_vms: if vm.is_running(): self.set_mapped_ip_info_for_vm(vm) self.reload_firewall_for_vm(vm)
[docs] @qubes.events.handler('firewall-changed', 'domain-spawn') def on_firewall_changed(self, event, **kwargs): ''' Reloads the firewall if vm is running and has a NetVM assigned ''' # pylint: disable=unused-argument if self.is_running() and self.netvm: self.netvm.reload_connected_ips() self.netvm.set_mapped_ip_info_for_vm(self) self.netvm.reload_firewall_for_vm(self) # pylint: disable=no-member
# CORE2: swallowed get_firewall_conf, write_firewall_conf, # get_firewall_defaults @property def firewall(self): if self._firewall is None: self._firewall = qubes.firewall.Firewall(self) return self._firewall
[docs] def has_firewall(self): ''' Return `True` if there are some vm specific firewall rules set ''' return os.path.exists(os.path.join(self.dir_path, self.firewall_conf))