## Copyright (C) 2008-2012 Kjell Braden ## Copyright (C) 2019 Pavel R. ## Copyright (C) 2022 Bohdan Horbeshko # # This file is part of Gajim OTR Plugin. # # Gajim OTR 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. # # This software 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 can always obtain full license text at . import os import string import random import itertools import logging from gajim.common import const, app, helpers, configpaths from gajim.common.const import EncryptionData from gajim.common.structs import OutgoingMessage from nbxmpp.protocol import Message, JID from nbxmpp.simplexml import Node import pathlib import sys sys.path.insert(0, pathlib.Path(__file__).parent.resolve()) sys.modules['gajim_otrplugin'] = sys.modules['gajim-otrplugin'] from gajim_otrplugin.potr import context, crypt, proto from .keystore import Keystore # Prototype of OTR Channel (secure conversations between Gajim user (Alice) and Gajim peer (Bob) class OTRChannel(context.Context): # this method may be called self.sendMessage() when we need to send some data to our via XMPP def inject(self,msg,appdata=None): stanza = Message(to=self.peer, body=msg.decode(), typ='chat') stanza.setThread(appdata or self.generateThreadId()) self.user.stream.send_stanza(stanza) # this method called on channel state change def setState(self,state=0): if state and state != self.state: self.getCurrentTrust() is None and self.setCurrentTrust(0) != 0 and self.printl(OTR.TRUSTED[None].format(fprint=self.getCurrentKey())) # new fingerprint self.printl(OTR.STATUS[state].format(peer=self.peer,trust=OTR.TRUSTED[self.getCurrentTrust()],fprint=self.getCurrentKey())) # state is changed self.state = state # print some text to chat window def printl(self,line): control = app.window.get_control() control and control.add_info_message("OTR: "+line) @staticmethod def getPolicy(policy): return OTR.DEFAULT_POLICY.get(policy) @staticmethod def generateThreadId(): return ''.join( [f(string.ascii_letters) for f in itertools.repeat( random.choice, 32)] ) # OTR instance for Gajim user (Alice) class OTR(context.Account): PROTO = ('XMPP', 1024) ENCRYPTION_NAME = ('OTR') DEFAULT_POLICY = { 'REQUIRE_ENCRYPTION': True, 'ALLOW_V1': False, 'ALLOW_V2': True, 'SEND_TAG': True, 'WHITESPACE_START_AKE': True, 'ERROR_START_AKE': True, } TRUSTED = {None:"new fingerprint received: *{fprint}*", 0:"untrusted", 1:"trusted", 2:"authenticated"} STATUS = { context.STATE_PLAINTEXT: "(re-)starting encrypted conversation with {peer}..", context.STATE_ENCRYPTED: "{trust} encrypted conversation started (fingerprint: {fprint})", context.STATE_FINISHED: "encrypted conversation with {peer} closed (fingerprint: {fprint})", context.UnencryptedMessage: "this message is *not encrypted*: {msg}", context.NotEncryptedError: "unable to process message (channel lost)", context.ErrorReceived: "received error message: {err}", crypt.InvalidParameterError: "unable to decrypt message (key/signature mismatch)", } def __init__(self,account): super(OTR,self).__init__(account,*OTR.PROTO) self.log = logging.getLogger('gajim.p.otr.otr') self.account = account self.stream = app.connections[account] self.jid = self.stream.get_own_jid() self.keystore = Keystore(os.path.join(configpaths.get('MY_DATA'), 'otr_' + self.jid.bare + '.db')) self.loadTrusts() # get chat control def getControl(self,peer): return app.window.get_control() # get OTR context (encrypted dialog between Alice and Bob) def getContext(self,peer): peer in self.ctxs and self.ctxs[peer].state == context.STATE_FINISHED and self.ctxs.pop(peer).disconnect() # close dead channels self.ctxs[peer] = self.ctxs.get(peer) or OTRChannel(self,peer) return self.ctxs[peer] # factory for Gajim 1.4+ def makeOutgoingMessage(self,message,control,peer): contact = control.client.get_module('Contacts').get_contact(peer, groupchat=False) chatstate = control.client.get_module('Chatstate').get_active_chatstate(contact) return OutgoingMessage(account=self.account, contact=contact, message=message, type_='chat', chatstate=chatstate, label=None, correct_id=None) # load my private key def loadPrivkey(self): my = self.keystore.load(jid=str(self.jid)) return (my and my.privatekey) and crypt.PK.parsePrivateKey(bytes.fromhex(my.privatekey))[0] or None # save my privatekey def savePrivkey(self): self.keystore.save(jid=str(self.jid),privatekey=self.getPrivkey().serializePrivateKey().hex()) # load known fingerprints def loadTrusts(self): for peer in self.keystore.load(): self.setTrust(peer.jid,peer.fingerprint,peer.trust) # save known fingerprints def saveTrusts(self): for peer,fingerprints in self.trusts.items(): for fingerprint,trust in fingerprints.items(): self.keystore.save(jid=str(peer),fingerprint=fingerprint,trust=trust) # decrypt message def decrypt(self,stanza,properties): sFrom = stanza.getFrom() peer = sFrom.new_as_bare() msgtxt = stanza.getBody() channel, ctl = self.getContext(peer), self.getControl(peer) try: text, tlvs = channel.receiveMessage(msgtxt.encode(),appdata=stanza.getThread()) or b'' except (context.UnencryptedMessage,context.NotEncryptedError,context.ErrorReceived,crypt.InvalidParameterError) as e: self.log.error("** got exception while decrypting message: %s" % e) channel.printl(OTR.STATUS[e].format(msg=msgtxt,err=e.args[0].error)) else: channel.resource = sFrom.resource stanza.setBody(text and text.decode() or "") properties.encrypted = EncryptionData({'name': OTR.ENCRYPTION_NAME}) finally: if channel.mayRetransmit and channel.state and ctl: channel.mayRetransmit = ctl.client.send_message(self.makeOutgoingMessage(channel.lastMessage.decode(), ctl, peer)) # encrypt message def encrypt(self,event,callback): peer = event.msg_iq.getTo().new_as_bare() channel, ctl = self.getContext(peer), self.getControl(peer) if not hasattr(channel, 'resource'): channel.resource = "" if channel.resource: peer = peer.new_with(resource=channel.resource) if event.xhtml: return ctl.client.send_message(self.makeOutgoingMessage(event.message, ctl, peer)) # skip xhtml messages try: encrypted = channel.sendMessage(context.FRAGMENT_SEND_ALL_BUT_LAST,event.message.encode(),appdata=event.msg_iq.getThread()) or b'' message = (encrypted != self.getDefaultQueryMessage(OTR.DEFAULT_POLICY.get)) and event.message or "" except context.NotEncryptedError as e: self.log.error("** got exception while encrypting message: %s" % e) channel.printl(peer,OTR.STATUS[e]) else: event.msg_iq.setBody(encrypted.decode()) # encrypted data goes here event.message = message # message that will be displayed in our chat goes here event.encrypted, event.additional_data["encrypted"] = OTR.ENCRYPTION_NAME, {"name":OTR.ENCRYPTION_NAME} # some mandatory encryption flags if channel.resource: event.stanza.addChild('no-copy', namespace='urn:xmpp:hints') # don't send carbons event.stanza.addChild('no-store', namespace='urn:xmpp:hints') # don't store in MAM callback(event)