107 lines
3.9 KiB
Python
107 lines
3.9 KiB
Python
#!/usr/bin/env python3
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# SAT plugin for Explicit Message Encryption
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# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from libervia.backend.core.i18n import _, D_
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from libervia.backend.core.constants import Const as C
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from libervia.backend.core.log import getLogger
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from twisted.words.protocols.jabber import jid
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log = getLogger(__name__)
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PLUGIN_INFO = {
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C.PI_NAME: "Explicit Message Encryption",
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C.PI_IMPORT_NAME: "XEP-0380",
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C.PI_TYPE: "SEC",
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C.PI_PROTOCOLS: ["XEP-0380"],
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C.PI_DEPENDENCIES: [],
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C.PI_MAIN: "XEP_0380",
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C.PI_HANDLER: "no",
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C.PI_DESCRIPTION: _("""Implementation of Explicit Message Encryption"""),
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}
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NS_EME = "urn:xmpp:eme:0"
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KNOWN_NAMESPACES = {
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"urn:xmpp:otr:0": "OTR",
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"jabber:x:encrypted": "Legacy OpenPGP",
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"urn:xmpp:openpgp:0": "OpenPGP for XMPP",
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}
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class XEP_0380(object):
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def __init__(self, host):
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self.host = host
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host.trigger.add("sendMessage", self._send_message_trigger)
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host.trigger.add("message_received", self._message_received_trigger, priority=100)
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host.register_namespace("eme", NS_EME)
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def _add_eme_element(self, mess_data, namespace, name):
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message_elt = mess_data["xml"]
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encryption_elt = message_elt.addElement((NS_EME, "encryption"))
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encryption_elt["namespace"] = namespace
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if name is not None:
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encryption_elt["name"] = name
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return mess_data
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def _send_message_trigger(self, client, mess_data, __, post_xml_treatments):
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encryption = mess_data.get(C.MESS_KEY_ENCRYPTION)
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if encryption is not None:
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namespace = encryption["plugin"].namespace
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if namespace not in KNOWN_NAMESPACES:
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name = encryption["plugin"].name
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else:
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name = None
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post_xml_treatments.addCallback(
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self._add_eme_element, namespace=namespace, name=name
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)
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return True
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def _message_received_trigger(self, client, message_elt, post_treat):
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try:
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encryption_elt = next(message_elt.elements(NS_EME, "encryption"))
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except StopIteration:
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return True
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namespace = encryption_elt["namespace"]
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if namespace in client.encryption.get_namespaces():
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# message is encrypted and we can decrypt it
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return True
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name = KNOWN_NAMESPACES.get(namespace, encryption_elt.getAttribute("name"))
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# at this point, message is encrypted but we know that we can't decrypt it,
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# we need to notify the user
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sender_s = message_elt["from"]
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to_jid = jid.JID(message_elt["from"])
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algorithm = "{} [{}]".format(name, namespace) if name else namespace
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log.warning(
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_(
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"Message from {sender} is encrypted with {algorithm} and we can't "
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"decrypt it.".format(sender=message_elt["from"], algorithm=algorithm)
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)
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)
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user_msg = D_(
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"User {sender} sent you an encrypted message (encrypted with {algorithm}), "
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"and we can't decrypt it."
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).format(sender=sender_s, algorithm=algorithm)
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extra = {C.MESS_EXTRA_INFO: C.EXTRA_INFO_DECR_ERR}
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client.feedback(to_jid, user_msg, extra)
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return False
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