Mercurial > libervia-backend
view sat/memory/encryption.py @ 3621:9e1a993ad1bf
core (memory/sqla): minor docstring line lenght fix
author | Goffi <goffi@goffi.org> |
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date | Mon, 02 Aug 2021 21:52:17 +0200 |
parents | be6d91572633 |
children | 8289ac1b34f4 |
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#!/usr/bin/env python3 # SAT: a jabber client # Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org) # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU Affero 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 Affero General Public License for more details. # You should have received a copy of the GNU Affero General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. import copy from functools import partial from collections import namedtuple from twisted.words.protocols.jabber import jid from twisted.internet import defer from twisted.python import failure from sat.core.i18n import D_, _ from sat.core.constants import Const as C from sat.core import exceptions from sat.core.log import getLogger from sat.tools.common import data_format from sat.tools import utils from sat.memory import persistent log = getLogger(__name__) EncryptionPlugin = namedtuple("EncryptionPlugin", ("instance", "name", "namespace", "priority", "directed")) class EncryptionHandler: """Class to handle encryption sessions for a client""" plugins = [] # plugin able to encrypt messages def __init__(self, client): self.client = client self._sessions = {} # bare_jid ==> encryption_data self._stored_session = persistent.PersistentDict( "core:encryption", profile=client.profile) @property def host(self): return self.client.host_app async def loadSessions(self): """Load persistent sessions""" await self._stored_session.load() start_d_list = [] for entity_jid_s, namespace in self._stored_session.items(): entity = jid.JID(entity_jid_s) start_d_list.append(defer.ensureDeferred(self.start(entity, namespace))) if start_d_list: result = await defer.DeferredList(start_d_list) for idx, (success, err) in enumerate(result): if not success: entity_jid_s, namespace = list(self._stored_session.items())[idx] log.warning(_( "Could not restart {namespace!r} encryption with {entity}: {err}" ).format(namespace=namespace, entity=entity_jid_s, err=err)) log.info(_("encryption sessions restored")) @classmethod def registerPlugin(cls, plg_instance, name, namespace, priority=0, directed=False): """Register a plugin handling an encryption algorithm @param plg_instance(object): instance of the plugin it must have the following methods: - getTrustUI(entity): return a XMLUI for trust management entity(jid.JID): entity to manage The returned XMLUI must be a form if may have the following methods: - startEncryption(entity): start encrypted session entity(jid.JID): entity to start encrypted session with - stopEncryption(entity): start encrypted session entity(jid.JID): entity to stop encrypted session with if they don't exists, those 2 methods will be ignored. @param name(unicode): human readable name of the encryption algorithm @param namespace(unicode): namespace of the encryption algorithm @param priority(int): priority of this plugin to encrypt an message when not selected manually @param directed(bool): True if this plugin is directed (if it works with one device only at a time) """ existing_ns = set() existing_names = set() for p in cls.plugins: existing_ns.add(p.namespace.lower()) existing_names.add(p.name.lower()) if namespace.lower() in existing_ns: raise exceptions.ConflictError("A plugin with this namespace already exists!") if name.lower() in existing_names: raise exceptions.ConflictError("A plugin with this name already exists!") plugin = EncryptionPlugin( instance=plg_instance, name=name, namespace=namespace, priority=priority, directed=directed) cls.plugins.append(plugin) cls.plugins.sort(key=lambda p: p.priority) log.info(_("Encryption plugin registered: {name}").format(name=name)) @classmethod def getPlugins(cls): return cls.plugins @classmethod def getPlugin(cls, namespace): try: return next(p for p in cls.plugins if p.namespace == namespace) except StopIteration: raise exceptions.NotFound(_( "Can't find requested encryption plugin: {namespace}").format( namespace=namespace)) @classmethod def getNamespaces(cls): """Get available plugin namespaces""" return {p.namespace for p in cls.getPlugins()} @classmethod def getNSFromName(cls, name): """Retrieve plugin namespace from its name @param name(unicode): name of the plugin (case insensitive) @return (unicode): namespace of the plugin @raise exceptions.NotFound: there is not encryption plugin of this name """ for p in cls.plugins: if p.name.lower() == name.lower(): return p.namespace raise exceptions.NotFound(_( "Can't find a plugin with the name \"{name}\".".format( name=name))) def getBridgeData(self, session): """Retrieve session data serialized for bridge. @param session(dict): encryption session @return (unicode): serialized data for bridge """ if session is None: return '' plugin = session['plugin'] bridge_data = {'name': plugin.name, 'namespace': plugin.namespace} if 'directed_devices' in session: bridge_data['directed_devices'] = session['directed_devices'] return data_format.serialise(bridge_data) async def _startEncryption(self, plugin, entity): """Start encryption with a plugin This method must be called just before adding a plugin session. StartEncryptionn method of plugin will be called if it exists. """ if not plugin.directed: await self._stored_session.aset(entity.userhost(), plugin.namespace) try: start_encryption = plugin.instance.startEncryption except AttributeError: log.debug(f"No startEncryption method found for {plugin.namespace}") else: # we copy entity to avoid having the resource changed by stop_encryption await utils.asDeferred(start_encryption, self.client, copy.copy(entity)) async def _stopEncryption(self, plugin, entity): """Stop encryption with a plugin This method must be called just before removing a plugin session. StopEncryptionn method of plugin will be called if it exists. """ try: await self._stored_session.adel(entity.userhost()) except KeyError: pass try: stop_encryption = plugin.instance.stopEncryption except AttributeError: log.debug(f"No stopEncryption method found for {plugin.namespace}") else: # we copy entity to avoid having the resource changed by stop_encryption return utils.asDeferred(stop_encryption, self.client, copy.copy(entity)) async def start(self, entity, namespace=None, replace=False): """Start an encryption session with an entity @param entity(jid.JID): entity to start an encryption session with must be bare jid is the algorithm encrypt for all devices @param namespace(unicode, None): namespace of the encryption algorithm to use. None to select automatically an algorithm @param replace(bool): if True and an encrypted session already exists, it will be replaced by the new one """ if not self.plugins: raise exceptions.NotFound(_("No encryption plugin is registered, " "an encryption session can't be started")) if namespace is None: plugin = self.plugins[0] else: plugin = self.getPlugin(namespace) bare_jid = entity.userhostJID() if bare_jid in self._sessions: # we have already an encryption session with this contact former_plugin = self._sessions[bare_jid]["plugin"] if former_plugin.namespace == namespace: log.info(_("Session with {bare_jid} is already encrypted with {name}. " "Nothing to do.").format( bare_jid=bare_jid, name=former_plugin.name)) return if replace: # there is a conflict, but replacement is requested # so we stop previous encryption to use new one del self._sessions[bare_jid] await self._stopEncryption(former_plugin, entity) else: msg = (_("Session with {bare_jid} is already encrypted with {name}. " "Please stop encryption session before changing algorithm.") .format(bare_jid=bare_jid, name=plugin.name)) log.warning(msg) raise exceptions.ConflictError(msg) data = {"plugin": plugin} if plugin.directed: if not entity.resource: entity.resource = self.host.memory.getMainResource(self.client, entity) if not entity.resource: raise exceptions.NotFound( _("No resource found for {destinee}, can't encrypt with {name}") .format(destinee=entity.full(), name=plugin.name)) log.info(_("No resource specified to encrypt with {name}, using " "{destinee}.").format(destinee=entity.full(), name=plugin.name)) # indicate that we encrypt only for some devices directed_devices = data['directed_devices'] = [entity.resource] elif entity.resource: raise ValueError(_("{name} encryption must be used with bare jids.")) await self._startEncryption(plugin, entity) self._sessions[entity.userhostJID()] = data log.info(_("Encryption session has been set for {entity_jid} with " "{encryption_name}").format( entity_jid=entity.full(), encryption_name=plugin.name)) self.host.bridge.messageEncryptionStarted( entity.full(), self.getBridgeData(data), self.client.profile) msg = D_("Encryption session started: your messages with {destinee} are " "now end to end encrypted using {name} algorithm.").format( destinee=entity.full(), name=plugin.name) directed_devices = data.get('directed_devices') if directed_devices: msg += "\n" + D_("Message are encrypted only for {nb_devices} device(s): " "{devices_list}.").format( nb_devices=len(directed_devices), devices_list = ', '.join(directed_devices)) self.client.feedback(bare_jid, msg) async def stop(self, entity, namespace=None): """Stop an encryption session with an entity @param entity(jid.JID): entity with who the encryption session must be stopped must be bare jid if the algorithm encrypt for all devices @param namespace(unicode): namespace of the session to stop when specified, used to check that we stop the right encryption session """ session = self.getSession(entity.userhostJID()) if not session: raise failure.Failure( exceptions.NotFound(_("There is no encryption session with this " "entity."))) plugin = session['plugin'] if namespace is not None and plugin.namespace != namespace: raise exceptions.InternalError(_( "The encryption session is not run with the expected plugin: encrypted " "with {current_name} and was expecting {expected_name}").format( current_name=session['plugin'].namespace, expected_name=namespace)) if entity.resource: try: directed_devices = session['directed_devices'] except KeyError: raise exceptions.NotFound(_( "There is a session for the whole entity (i.e. all devices of the " "entity), not a directed one. Please use bare jid if you want to " "stop the whole encryption with this entity.")) try: directed_devices.remove(entity.resource) except ValueError: raise exceptions.NotFound(_("There is no directed session with this " "entity.")) else: if not directed_devices: # if we have no more directed device sessions, # we stop the whole session # see comment below for deleting session before stopping encryption del self._sessions[entity.userhostJID()] await self._stopEncryption(plugin, entity) else: # plugin's stopEncryption may call stop again (that's the case with OTR) # so we need to remove plugin from session before calling self._stopEncryption del self._sessions[entity.userhostJID()] await self._stopEncryption(plugin, entity) log.info(_("encryption session stopped with entity {entity}").format( entity=entity.full())) self.host.bridge.messageEncryptionStopped( entity.full(), {'name': plugin.name, 'namespace': plugin.namespace, }, self.client.profile) msg = D_("Encryption session finished: your messages with {destinee} are " "NOT end to end encrypted anymore.\nYour server administrators or " "{destinee} server administrators will be able to read them.").format( destinee=entity.full()) self.client.feedback(entity, msg) def getSession(self, entity): """Get encryption session for this contact @param entity(jid.JID): get the session for this entity must be a bare jid @return (dict, None): encryption session data None if there is not encryption for this session with this jid """ if entity.resource: raise ValueError("Full jid given when expecting bare jid") return self._sessions.get(entity) def getTrustUI(self, entity_jid, namespace=None): """Retrieve encryption UI @param entity_jid(jid.JID): get the UI for this entity must be a bare jid @param namespace(unicode): namespace of the algorithm to manage if None use current algorithm @return D(xmlui): XMLUI for trust management the xmlui is a form None if there is not encryption for this session with this jid @raise exceptions.NotFound: no algorithm/plugin found @raise NotImplementedError: plugin doesn't handle UI management """ if namespace is None: session = self.getSession(entity_jid) if not session: raise exceptions.NotFound( "No encryption session currently active for {entity_jid}" .format(entity_jid=entity_jid.full())) plugin = session['plugin'] else: plugin = self.getPlugin(namespace) try: get_trust_ui = plugin.instance.getTrustUI except AttributeError: raise NotImplementedError( "Encryption plugin doesn't handle trust management UI") else: return utils.asDeferred(get_trust_ui, self.client, entity_jid) ## Menus ## @classmethod def _importMenus(cls, host): host.importMenu( (D_("Encryption"), D_("unencrypted (plain text)")), partial(cls._onMenuUnencrypted, host=host), security_limit=0, help_string=D_("End encrypted session"), type_=C.MENU_SINGLE, ) for plg in cls.getPlugins(): host.importMenu( (D_("Encryption"), plg.name), partial(cls._onMenuName, host=host, plg=plg), security_limit=0, help_string=D_("Start {name} session").format(name=plg.name), type_=C.MENU_SINGLE, ) host.importMenu( (D_("Encryption"), D_("⛨ {name} trust").format(name=plg.name)), partial(cls._onMenuTrust, host=host, plg=plg), security_limit=0, help_string=D_("Manage {name} trust").format(name=plg.name), type_=C.MENU_SINGLE, ) @classmethod def _onMenuUnencrypted(cls, data, host, profile): client = host.getClient(profile) peer_jid = jid.JID(data['jid']).userhostJID() d = defer.ensureDeferred(client.encryption.stop(peer_jid)) d.addCallback(lambda __: {}) return d @classmethod def _onMenuName(cls, data, host, plg, profile): client = host.getClient(profile) peer_jid = jid.JID(data['jid']) if not plg.directed: peer_jid = peer_jid.userhostJID() d = defer.ensureDeferred( client.encryption.start(peer_jid, plg.namespace, replace=True)) d.addCallback(lambda __: {}) return d @classmethod @defer.inlineCallbacks def _onMenuTrust(cls, data, host, plg, profile): client = host.getClient(profile) peer_jid = jid.JID(data['jid']).userhostJID() ui = yield client.encryption.getTrustUI(peer_jid, plg.namespace) defer.returnValue({'xmlui': ui.toXml()}) ## Triggers ## def setEncryptionFlag(self, mess_data): """Set "encryption" key in mess_data if session with destinee is encrypted""" to_jid = mess_data['to'] encryption = self._sessions.get(to_jid.userhostJID()) if encryption is not None: plugin = encryption['plugin'] if mess_data["type"] == "groupchat" and plugin.directed: raise exceptions.InternalError( f"encryption flag must not be set for groupchat if encryption algorithm " f"({encryption['plugin'].name}) is directed!") mess_data[C.MESS_KEY_ENCRYPTION] = encryption self.markAsEncrypted(mess_data, plugin.namespace) ## Misc ## def markAsEncrypted(self, mess_data, namespace): """Helper method to mark a message as having been e2e encrypted. This should be used in the post_treat workflow of messageReceived trigger of the plugin @param mess_data(dict): message data as used in post treat workflow @param namespace(str): namespace of the algorithm used for encrypting the message """ mess_data['extra'][C.MESS_KEY_ENCRYPTED] = True from_bare_jid = mess_data['from'].userhostJID() if from_bare_jid != self.client.jid.userhostJID(): session = self.getSession(from_bare_jid) if session is None: # if we are currently unencrypted, we start a session automatically # to avoid sending unencrypted messages in an encrypted context log.info(_( "Starting e2e session with {peer_jid} as we receive encrypted " "messages") .format(peer_jid=from_bare_jid) ) defer.ensureDeferred(self.start(from_bare_jid, namespace)) return mess_data def isEncryptionRequested(self, mess_data, namespace=None): """Helper method to check if encryption is requested in an outgoind message @param mess_data(dict): message data for outgoing message @param namespace(str, None): if set, check if encryption is requested for the algorithm specified @return (bool): True if the encryption flag is present """ encryption = mess_data.get(C.MESS_KEY_ENCRYPTION) if encryption is None: return False # we get plugin even if namespace is None to be sure that the key exists plugin = encryption['plugin'] if namespace is None: return True return plugin.namespace == namespace def isEncrypted(self, mess_data): """Helper method to check if a message has the e2e encrypted flag @param mess_data(dict): message data @return (bool): True if the encrypted flag is present """ return mess_data['extra'].get(C.MESS_KEY_ENCRYPTED, False) def markAsTrusted(self, mess_data): """Helper methor to mark a message as sent from a trusted entity. This should be used in the post_treat workflow of messageReceived trigger of the plugin @param mess_data(dict): message data as used in post treat workflow """ mess_data[C.MESS_KEY_TRUSTED] = True return mess_data def markAsUntrusted(self, mess_data): """Helper methor to mark a message as sent from an untrusted entity. This should be used in the post_treat workflow of messageReceived trigger of the plugin @param mess_data(dict): message data as used in post treat workflow """ mess_data['trusted'] = False return mess_data