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# Copyright (C) 2019 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of OMEMO Gajim Plugin.
#
# OMEMO Gajim Plugin 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; version 3 only.
#
# OMEMO Gajim Plugin 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 OMEMO Gajim Plugin. If not, see <http://www.gnu.org/licenses/>.
# XEP-0384: OMEMO Encryption
import time
from pathlib import Path
from nbxmpp.namespaces import Namespace
from nbxmpp.protocol import NodeProcessed
from nbxmpp.errors import StanzaError
from nbxmpp.const import PresenceType
from nbxmpp.const import Affiliation
from nbxmpp.structs import StanzaHandler
from nbxmpp.modules.omemo import create_omemo_message
from nbxmpp.modules.omemo import get_key_transport_message
from nbxmpp.modules.util import is_error
from gajim.common import app
from gajim.common import configpaths
from gajim.common.events import MessageNotSent
from gajim.common.const import EncryptionData
from gajim.common.const import Trust as GajimTrust
from gajim.common.modules.base import BaseModule
from gajim.common.modules.util import event_node
from gajim.common.modules.util import as_task
from gajim.plugins.plugins_i18n import _
from omemo.backend.state import OmemoState
from omemo.backend.state import KeyExchangeMessage
from omemo.backend.state import SelfMessage
from omemo.backend.state import MessageNotForDevice
from omemo.backend.state import DecryptionFailed
from omemo.backend.state import DuplicateMessage
from omemo.backend.util import Trust
from omemo.modules.events import OMEMONewFingerprint
from omemo.modules.util import prepare_stanza
ALLOWED_TAGS = [
('request', Namespace.RECEIPTS),
('active', Namespace.CHATSTATES),
('gone', Namespace.CHATSTATES),
('inactive', Namespace.CHATSTATES),
('paused', Namespace.CHATSTATES),
('composing', Namespace.CHATSTATES),
('markable', Namespace.CHATMARKERS),
('no-store', Namespace.HINTS),
('store', Namespace.HINTS),
('no-copy', Namespace.HINTS),
('no-permanent-store', Namespace.HINTS),
('replace', Namespace.CORRECT),
('thread', None),
('origin-id', Namespace.SID),
]
ENCRYPTION_NAME = 'OMEMO'
# Module name
name = 'OMEMO'
zeroconf = False
class OMEMO(BaseModule):
_nbxmpp_extends = 'OMEMO'
_nbxmpp_methods = [
'set_devicelist',
'request_devicelist',
'set_bundle',
'request_bundle',
]
def __init__(self, client):
BaseModule.__init__(self, client, plugin=True)
self.handlers = [
StanzaHandler(name='message',
callback=self._message_received,
ns=Namespace.OMEMO_TEMP,
priority=9),
StanzaHandler(name='presence',
callback=self._on_muc_user_presence,
ns=Namespace.MUC_USER,
priority=48),
]
self._register_pubsub_handler(self._devicelist_notification_received)
self.available = True
self._own_jid = self._client.get_own_jid().bare
self._backend = self._get_backend()
self._omemo_groupchats = set()
self._muc_temp_store = {}
self._query_for_bundles = []
self._device_bundle_querys = []
self._query_for_devicelists = []
def get_own_jid(self, stripped=False):
if stripped:
return self._client.get_own_jid().bare
return self._client.get_own_jid()
@property
def backend(self):
return self._backend
def _get_backend(self):
data_dir = Path(configpaths.get('MY_DATA'))
db_path = data_dir / f'omemo_{self._own_jid}.db'
return OmemoState(self._own_jid, db_path, self._account, self)
def is_omemo_groupchat(self, room_jid):
return room_jid in self._omemo_groupchats
def on_signed_in(self):
self._log.info('Announce Support after Sign In')
self._query_for_bundles = []
self.set_bundle()
self.request_devicelist()
def activate(self):
""" Method called when the Plugin is activated in the PluginManager
"""
self._client.get_module('Caps').update_caps()
if app.account_is_connected(self._account):
self._log.info('Announce Support after Plugin Activation')
self._query_for_bundles = []
self.set_bundle()
self.request_devicelist()
def deactivate(self):
""" Method called when the Plugin is deactivated in the PluginManager
"""
self._query_for_bundles = []
def encrypt_message(self, conn, event, callback, groupchat):
if not event.message:
callback(event)
return
omemo_message = self.backend.encrypt(event.jid, event.message)
if omemo_message is None:
app.ged.raise_event(
MessageNotSent(client=conn,
jid=event.jid,
message=event.message,
error=_('Encryption error'),
time=time.time()))
return
create_omemo_message(event.stanza, omemo_message,
node_whitelist=ALLOWED_TAGS)
if groupchat:
self._muc_temp_store[omemo_message.payload] = event.message
else:
event.xhtml = None
event.encrypted = ENCRYPTION_NAME
event.additional_data['encrypted'] = {
'name': ENCRYPTION_NAME,
'trust': GajimTrust[Trust.VERIFIED.name]}
self._debug_print_stanza(event.stanza)
callback(event)
def _send_key_transport_message(self, typ, jid, devices):
omemo_message = self.backend.encrypt_key_transport(jid, devices)
if omemo_message is None:
self._log.warning('Key transport message to %s (%s) failed',
jid, devices)
return
transport_message = get_key_transport_message(typ, jid, omemo_message)
self._log.info('Send key transport message %s (%s)', jid, devices)
self._client.connection.send(transport_message)
def _message_received(self, _con, stanza, properties):
if not properties.is_omemo:
return
if properties.is_carbon_message and properties.carbon.is_sent:
from_jid = self._own_jid
elif properties.is_mam_message:
from_jid = self._process_mam_message(properties)
elif properties.from_muc:
from_jid = self._process_muc_message(properties)
else:
from_jid = properties.jid.bare
if from_jid is None:
return
self._log.info('Message received from: %s', from_jid)
try:
plaintext, fingerprint, trust = self.backend.decrypt_message(
properties.omemo, from_jid)
except (KeyExchangeMessage, DuplicateMessage):
raise NodeProcessed
except SelfMessage:
if not properties.from_muc:
raise NodeProcessed
if properties.omemo.payload not in self._muc_temp_store:
self._log.warning("Can't decrypt own GroupChat Message")
return
plaintext = self._muc_temp_store[properties.omemo.payload]
fingerprint = self.backend.own_fingerprint
trust = Trust.VERIFIED
del self._muc_temp_store[properties.omemo.payload]
except DecryptionFailed:
return
except MessageNotForDevice:
if properties.omemo.payload is None:
# Key Transport message for another device
return
plaintext = _('This message was encrypted with OMEMO, '
'but not for your device.')
# Neither trust nor fingerprint can be verified if we didn't
# successfully decrypt the message
trust = Trust.UNTRUSTED
fingerprint = None
prepare_stanza(stanza, plaintext)
self._debug_print_stanza(stanza)
properties.encrypted = EncryptionData({'name': ENCRYPTION_NAME,
'fingerprint': fingerprint,
'trust': GajimTrust[trust.name]})
def _process_muc_message(self, properties):
resource = properties.jid.resource
if properties.muc_ofrom is not None:
# History Message from MUC
return properties.muc_ofrom.bare
contact = self._client.get_module('Contacts').get_contact(
properties.jid)
if contact.real_jid is not None:
return contact.real_jid.bare
self._log.info('Groupchat: Last resort trying to find SID in DB')
from_jid = self.backend.storage.getJidFromDevice(properties.omemo.sid)
if not from_jid:
self._log.error("Can't decrypt GroupChat Message from %s", resource)
return
return from_jid
def _process_mam_message(self, properties):
self._log.info('Message received, archive: %s', properties.mam.archive)
if properties.from_muc:
self._log.info('MUC MAM Message received')
if properties.muc_user is None or properties.muc_user.jid is None:
self._log.warning('Received MAM Message which can '
'not be mapped to a real jid')
return
return properties.muc_user.jid.bare
return properties.from_.bare
def _on_muc_user_presence(self, _con, _stanza, properties):
if properties.type == PresenceType.ERROR:
return
if properties.is_muc_destroyed:
return
room = properties.jid.bare
if properties.muc_user is None or properties.muc_user.jid is None:
# No real jid found
return
jid = properties.muc_user.jid.bare
if properties.muc_user.affiliation in (Affiliation.OUTCAST,
Affiliation.NONE):
self.backend.remove_muc_member(room, jid)
else:
self.backend.add_muc_member(room, jid)
if self.is_omemo_groupchat(room):
if not self.is_contact_in_roster(jid):
# Query Devicelists from JIDs not in our Roster
self._log.info('%s not in Roster, query devicelist...', jid)
self.request_devicelist(jid)
def get_affiliation_list(self, room_jid):
for affiliation in ('owner', 'admin', 'member'):
self._nbxmpp('MUC').get_affiliation(
room_jid,
affiliation,
callback=self._on_affiliations_received,
user_data=room_jid)
def _on_affiliations_received(self, task):
room_jid = task.get_user_data()
try:
result = task.finish()
except StanzaError as error:
self._log.info('Affiliation request failed: %s', error)
return
for user_jid in result.users:
jid = str(user_jid)
self.backend.add_muc_member(room_jid, jid)
if not self.is_contact_in_roster(jid):
# Query Devicelists from JIDs not in our Roster
self._log.info('%s not in Roster, query devicelist...', jid)
self.request_devicelist(jid)
def is_contact_in_roster(self, jid):
if jid == self._own_jid:
return True
roster_item = self._client.get_module('Roster').get_item(jid)
if roster_item is None:
return False
contact = self._client.get_module('Contacts').get_contact(jid)
return contact.subscription == 'both'
def on_muc_disco_update(self, event):
self._check_if_omemo_capable(event.jid)
def on_room_joined(self, contact):
jid = str(contact.jid)
self._check_if_omemo_capable(jid)
if self.is_omemo_groupchat(jid):
self.get_affiliation_list(jid)
def _check_if_omemo_capable(self, jid):
disco_info = app.storage.cache.get_last_disco_info(jid)
if disco_info.muc_is_members_only and disco_info.muc_is_nonanonymous:
self._log.info('OMEMO room discovered: %s', jid)
self._omemo_groupchats.add(jid)
else:
self._log.info('OMEMO room removed due to config change: %s', jid)
self._omemo_groupchats.discard(jid)
def _check_for_missing_sessions(self, jid):
devices_without_session = self.backend.devices_without_sessions(jid)
for device_id in devices_without_session:
if device_id in self._device_bundle_querys:
continue
self._device_bundle_querys.append(device_id)
self.request_bundle(jid, device_id)
def are_keys_missing(self, contact_jid):
""" Checks if devicekeys are missing and queries the
bundles
Parameters
----------
contact_jid : str
bare jid of the contact
Returns
-------
bool
Returns True if there are no trusted Fingerprints
"""
# Fetch Bundles of own other Devices
if self._own_jid not in self._query_for_bundles:
devices_without_session = self.backend \
.devices_without_sessions(self._own_jid)
self._query_for_bundles.append(self._own_jid)
if devices_without_session:
for device_id in devices_without_session:
self.request_bundle(self._own_jid, device_id)
# Fetch Bundles of contacts devices
if contact_jid not in self._query_for_bundles:
devices_without_session = self.backend \
.devices_without_sessions(contact_jid)
self._query_for_bundles.append(contact_jid)
if devices_without_session:
for device_id in devices_without_session:
self.request_bundle(contact_jid, device_id)
if self.backend.has_trusted_keys(contact_jid):
return False
return True
def set_bundle(self):
self._nbxmpp('OMEMO').set_bundle(self.backend.bundle,
self.backend.own_device)
@as_task
def request_bundle(self, jid, device_id):
_task = yield
self._log.info('Fetch device bundle %s %s', device_id, jid)
bundle = yield self._nbxmpp('OMEMO').request_bundle(
jid,
device_id)
if is_error(bundle) or bundle is None:
self._log.info('Bundle request failed: %s %s: %s',
jid, device_id, bundle)
return
self.backend.build_session(jid, device_id, bundle)
self._log.info('Session created for: %s', jid)
# TODO: In MUC we should send a groupchat message
self._send_key_transport_message('chat', jid, [device_id])
# Trigger dialog to trust new Fingerprints if
# the Chat Window is Open
# TODO: This does not work anymore
# ctrl = app.window.get_control(self._account, jid)
# if ctrl:
# app.ged.raise_event(OMEMONewFingerprint(chat_control=ctrl))
def set_devicelist(self, devicelist=None):
devicelist_ = set([self.backend.own_device])
if devicelist is not None:
devicelist_.update(devicelist)
self._log.info('Publishing own devicelist: %s', devicelist_)
self._nbxmpp('OMEMO').set_devicelist(devicelist_)
def clear_devicelist(self):
self.backend.update_devicelist(self._own_jid, [self.backend.own_device])
self.set_devicelist()
@as_task
def request_devicelist(self, jid=None):
_task = yield
if jid is None:
jid = self._own_jid
if jid in self._query_for_devicelists:
return
self._query_for_devicelists.append(jid)
devicelist = yield self._nbxmpp('OMEMO').request_devicelist(jid=jid)
if is_error(devicelist) or devicelist is None:
self._log.info('Devicelist request failed: %s %s', jid, devicelist)
devicelist = []
self._process_devicelist_update(jid, devicelist)
@event_node(Namespace.OMEMO_TEMP_DL)
def _devicelist_notification_received(self, _con, _stanza, properties):
if properties.pubsub_event.retracted:
return
devicelist = properties.pubsub_event.data or []
self._process_devicelist_update(str(properties.jid), devicelist)
def _process_devicelist_update(self, jid, devicelist):
own_devices = jid is None or self._client.get_own_jid().bare_match(jid)
if own_devices:
jid = self._own_jid
self._log.info('Received device list for %s: %s', jid, devicelist)
# Pass a copy, we need the full list for potential set_devicelist()
self.backend.update_devicelist(jid, list(devicelist))
if jid in self._query_for_bundles:
self._query_for_bundles.remove(jid)
if own_devices:
if not self.backend.is_own_device_published:
# Our own device_id is not in the list, it could be
# overwritten by some other client
self.set_devicelist(devicelist)
self._check_for_missing_sessions(jid)
def _debug_print_stanza(self, stanza):
stanzastr = '\n' + stanza.__str__(fancy=True)
stanzastr = stanzastr[0:-1]
self._log.debug(stanzastr)
def get_instance(*args, **kwargs):
return OMEMO(*args, **kwargs), 'OMEMO'
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