24468a9138
- encryptionNamespaceGet retrieves algorithm namespace from its short name - encryptionTrustUIGet retrieves trust mangement XMLUI from encryption plugin - new markAsUntrusted internal helper method, to add untrusted flag to message data
335 lines
14 KiB
Python
335 lines
14 KiB
Python
#!/usr/bin/env python2
|
|
# -*- coding: utf-8 -*-
|
|
|
|
# SAT: a jabber client
|
|
# Copyright (C) 2009-2018 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/>.
|
|
|
|
from sat.core.i18n import D_, _
|
|
from sat.core.constants import Const as C
|
|
from sat.core import exceptions
|
|
from collections import namedtuple
|
|
from sat.core.log import getLogger
|
|
log = getLogger(__name__)
|
|
from sat.tools.common import data_format
|
|
|
|
|
|
EncryptionPlugin = namedtuple("EncryptionPlugin", ("instance",
|
|
"name",
|
|
"namespace",
|
|
"priority",
|
|
"directed"))
|
|
|
|
|
|
class EncryptionHandler(object):
|
|
"""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
|
|
|
|
@property
|
|
def host(self):
|
|
return self.client.host_app
|
|
|
|
@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
|
|
|
|
@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(_(u"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(_(
|
|
u"Can't find requested encryption plugin: {namespace}").format(
|
|
namespace=namespace))
|
|
|
|
@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(_(
|
|
u"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 u''
|
|
plugin = session[u'plugin']
|
|
bridge_data = {'name': plugin.name,
|
|
'namespace': plugin.namespace}
|
|
if u'directed_devices' in session:
|
|
bridge_data[u'directed_devices'] = session[u'directed_devices']
|
|
|
|
return data_format.serialise(bridge_data)
|
|
|
|
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(_(u"No encryption plugin is registered, "
|
|
u"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(_(u"Session with {bare_jid} is already encrypted with {name}. "
|
|
u"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]
|
|
else:
|
|
msg = (_(u"Session with {bare_jid} is already encrypted with {name}. "
|
|
u"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(
|
|
_(u"No resource found for {destinee}, can't encrypt with {name}")
|
|
.format(destinee=entity.full(), name=plugin.name))
|
|
log.info(_(u"No resource specified to encrypt with {name}, using "
|
|
u"{destinee}.").format(destinee=entity.full(),
|
|
name=plugin.name))
|
|
# indicate that we encrypt only for some devices
|
|
directed_devices = data[u'directed_devices'] = [entity.resource]
|
|
elif entity.resource:
|
|
raise ValueError(_(u"{name} encryption must be used with bare jids."))
|
|
|
|
self._sessions[entity.userhostJID()] = data
|
|
log.info(_(u"Encryption session has been set for {entity_jid} with "
|
|
u"{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_(u"Encryption session started: your messages with {destinee} are "
|
|
u"now end to end encrypted using {name} algorithm.").format(
|
|
destinee=entity.full(), name=plugin.name)
|
|
directed_devices = data.get(u'directed_devices')
|
|
if directed_devices:
|
|
msg += u"\n" + D_(u"Message are encrypted only for {nb_devices} device(s): "
|
|
u"{devices_list}.").format(
|
|
nb_devices=len(directed_devices),
|
|
devices_list = u', '.join(directed_devices))
|
|
|
|
self.client.feedback(bare_jid, msg)
|
|
|
|
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 is the algorithm encrypt for all devices
|
|
@param namespace(unicode): namespace of the session to stop
|
|
when specified, used to check we stop the right encryption session
|
|
"""
|
|
session = self.getSession(entity.userhostJID())
|
|
if not session:
|
|
raise exceptions.NotFound(_(u"There is no encryption session with this "
|
|
u"entity."))
|
|
plugin = session['plugin']
|
|
if namespace is not None and plugin.namespace != namespace:
|
|
raise exceptions.InternalError(_(
|
|
u"The encryption session is not run with the expected plugin: encrypted "
|
|
u"with {current_name} and was expecting {expected_name}").format(
|
|
current_name=session[u'plugin'].namespace,
|
|
expected_name=namespace))
|
|
if entity.resource:
|
|
try:
|
|
directed_devices = session[u'directed_devices']
|
|
except KeyError:
|
|
raise exceptions.NotFound(_(
|
|
u"There is a session for the whole entity (i.e. all devices of the "
|
|
u"entity), not a directed one. Please use bare jid if you want to "
|
|
u"stop the whole encryption with this entity."))
|
|
|
|
try:
|
|
directed_devices.remove(entity.resource)
|
|
except ValueError:
|
|
raise exceptions.NotFound(_(u"There is no directed session with this "
|
|
u"entity."))
|
|
else:
|
|
if not directed_devices:
|
|
del session[u'directed_devices']
|
|
else:
|
|
del self._sessions[entity]
|
|
|
|
log.info(_(u"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_(u"Encryption session finished: your messages with {destinee} are "
|
|
u"NOT end to end encrypted anymore.\nYour server administrators or "
|
|
u"{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(u"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(
|
|
u"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(
|
|
u"Encryption plugin doesn't handle trust management UI")
|
|
else:
|
|
return get_trust_ui(self.client, entity_jid)
|
|
|
|
## Triggers ##
|
|
|
|
def setEncryptionFlag(self, mess_data):
|
|
"""Set "encryption" key in mess_data if session with destinee is encrypted"""
|
|
|
|
if mess_data["type"] == "groupchat":
|
|
# FIXME: to change when group chat encryption will be handled
|
|
return
|
|
|
|
to_jid = mess_data['to']
|
|
encryption = self._sessions.get(to_jid.userhostJID())
|
|
if encryption is not None:
|
|
mess_data[C.MESS_KEY_ENCRYPTION] = encryption
|
|
|
|
## Misc ##
|
|
|
|
def markAsEncrypted(self, mess_data):
|
|
"""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
|
|
"""
|
|
mess_data['encrypted'] = 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['untrusted'] = True
|
|
return mess_data
|