Files
gajim-plugins/openpgp/modules/openpgp.py
2018-08-29 23:39:34 +02:00

539 lines
18 KiB
Python

# Copyright (C) 2018 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of Gajim.
#
# Gajim 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.
#
# Gajim 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 Gajim. If not, see <http://www.gnu.org/licenses/>.
# XEP-0373: OpenPGP for XMPP
import time
import logging
from pathlib import Path
from base64 import b64decode, b64encode
from nbxmpp import Node, isResultNode
from gajim.common import app
from gajim.common import configpaths
from gajim.common.connection_handlers_events import MessageNotSentEvent
from openpgp.modules import util
from openpgp.modules.util import NS_OPENPGP_PUBLIC_KEYS
from openpgp.modules.util import NS_OPENPGP
from openpgp.modules.util import Key
from openpgp.modules.util import Trust
from openpgp.modules.util import VerifyFailed
from openpgp.modules.util import DecryptionFailed
from openpgp.backend.sql import Storage
from openpgp.backend.pygpg import PGPContext
log = logging.getLogger('gajim.plugin_system.openpgp')
ENCRYPTION_NAME = 'OpenPGP'
# Module name
name = 'OpenPGP'
zeroconf = False
class KeyData:
'''
Holds all data related to a certain key
'''
def __init__(self, contact_data):
self._contact_data = contact_data
self.fingerprint = None
self.active = False
self._trust = Trust.UNKNOWN
self.timestamp = None
self.comment = None
self.has_pubkey = False
@property
def trust(self):
return self._trust
@trust.setter
def trust(self, value):
if value not in (Trust.NOT_TRUSTED,
Trust.UNKNOWN,
Trust.BLIND,
Trust.VERIFIED):
raise ValueError('Trust value not allowed: %s' % value)
self._trust = value
self._contact_data.set_trust(self.fingerprint, self._trust)
@classmethod
def from_key(cls, contact_data, key, trust):
keydata = cls(contact_data)
keydata.fingerprint = key.fingerprint
keydata.timestamp = key.date
keydata.active = True
keydata._trust = trust
return keydata
@classmethod
def from_row(cls, contact_data, row):
keydata = cls(contact_data)
keydata.fingerprint = row.fingerprint
keydata.timestamp = row.timestamp
keydata.comment = row.comment
keydata._trust = row.trust
keydata.active = row.active
return keydata
def delete(self):
self._contact_data.delete_key(self.fingerprint)
class ContactData:
'''
Holds all data related to a contact
'''
def __init__(self, jid, storage, pgp):
self.jid = jid
self._key_store = {}
self._storage = storage
self._pgp = pgp
@property
def userid(self):
if self._jid is None:
raise ValueError('JID not set')
return 'xmpp:%s' % self._jid
@property
def default_trust(self):
for key in self._key_store:
if key.trust in (Trust.NOT_TRUSTED, Trust.BLIND):
return Trust.UNKNOWN
return Trust.BLIND
def db_values(self):
for key in self._key_store.values():
yield (self.jid,
key.fingerprint,
key.active,
key.trust,
key.timestamp,
key.comment)
def add_from_key(self, key):
try:
keydata = self._key_store[key.fingerprint]
except KeyError:
keydata = KeyData.from_key(self, key, self.default_trust)
self._key_store[key.fingerprint] = keydata
log.info('Add from key: %s %s', self.jid, keydata.fingerprint)
return keydata
def add_from_db(self, row):
try:
keydata = self._key_store[row.fingerprint]
except KeyError:
keydata = KeyData.from_row(self, row)
self._key_store[row.fingerprint] = keydata
log.info('Add from row: %s %s', self.jid, row.fingerprint)
return keydata
def process_keylist(self, keylist):
log.info('Process keylist: %s %s', self.jid, keylist)
if keylist is None:
for keydata in self._key_store.values():
keydata.active = False
self._storage.save_contact(self.db_values())
return []
missing_pub_keys = []
fingerprints = set([key.fingerprint for key in keylist])
if fingerprints == self._key_store.keys():
log.info('No updates found')
for key in self._key_store.values():
if not key.has_pubkey:
missing_pub_keys.append(key.fingerprint)
return missing_pub_keys
for keydata in self._key_store.values():
keydata.active = False
for key in keylist:
try:
keydata = self._key_store[key.fingerprint]
keydata.active = True
if not keydata.has_pubkey:
missing_pub_keys.append(keydata.fingerprint)
except KeyError:
keydata = self.add_from_key(key)
missing_pub_keys.append(keydata.fingerprint)
self._storage.save_contact(self.db_values())
return missing_pub_keys
def set_public_key(self, fingerprint):
try:
keydata = self._key_store[fingerprint]
except KeyError:
log.warning('Set public key on unknown fingerprint',
self.jid, fingerprint)
else:
keydata.has_pubkey = True
log.info('Set public key: %s %s', self.jid, fingerprint)
def get_keys(self, only_trusted=True):
keys = list(self._key_store.values())
if not only_trusted:
return keys
return [k for k in keys if k.active and k.trust in (Trust.VERIFIED,
Trust.BLIND)]
def set_trust(self, fingerprint, trust):
self._storage.set_trust(self.jid, fingerprint, trust)
def delete_key(self, fingerprint):
self._storage.delete_key(self.jid, fingerprint)
self._pgp.delete_key(fingerprint)
del self._key_store[fingerprint]
class PGPContacts:
'''
Holds all contacts available for PGP encryption
'''
def __init__(self, pgp, storage):
self._contacts = {}
self._storage = storage
self._pgp = pgp
self._load_from_storage()
self._load_from_keyring()
def _load_from_keyring(self):
log.info('Load keys from keyring')
keyring = self._pgp.get_keys()
for key in keyring:
log.info('Found: %s %s', key.jid, key.fingerprint)
self.set_public_key(key.jid, key.fingerprint)
def _load_from_storage(self):
log.info('Load contacts from storage')
rows = self._storage.load_contacts()
if rows is None:
return
for row in rows:
log.info('Found: %s %s', row.jid, row.fingerprint)
try:
contact_data = self._contacts[row.jid]
except KeyError:
contact_data = ContactData(row.jid, self._storage, self._pgp)
contact_data.add_from_db(row)
self._contacts[row.jid] = contact_data
else:
contact_data.add_from_db(row)
def process_keylist(self, jid, keylist):
try:
contact_data = self._contacts[jid]
except KeyError:
contact_data = ContactData(jid, self._storage, self._pgp)
missing_pub_keys = contact_data.process_keylist(keylist)
self._contacts[jid] = contact_data
else:
missing_pub_keys = contact_data.process_keylist(keylist)
return missing_pub_keys
def set_public_key(self, jid, fingerprint):
try:
contact_data = self._contacts[jid]
except KeyError:
log.warning('ContactData not found: %s %s', jid, fingerprint)
else:
contact_data.set_public_key(fingerprint)
def get_keys(self, jid, only_trusted=True):
try:
contact_data = self._contacts[jid]
return contact_data.get_keys(only_trusted=only_trusted)
except KeyError:
return []
class OpenPGP:
def __init__(self, con):
self._con = con
self._account = con.name
self.handlers = []
self.own_jid = self.get_own_jid(stripped=True)
path = Path(configpaths.get('MY_DATA')) / 'openpgp' / self.own_jid
if not path.exists():
path.mkdir(parents=True)
self._pgp = PGPContext(self.own_jid, path)
self._storage = Storage(path)
self._contacts = PGPContacts(self._pgp, self._storage)
self._fingerprint, self._date = self.get_own_key_details()
log.info('Own Fingerprint at start: %s', self._fingerprint)
@property
def secret_key_available(self):
return self._fingerprint is not None
def get_own_jid(self, stripped=False):
if stripped:
return self._con.get_own_jid().getStripped()
return self._con.get_own_jid()
def get_own_key_details(self):
self._fingerprint, self._date = self._pgp.get_own_key_details()
return self._fingerprint, self._date
def generate_key(self):
self._pgp.generate_key()
def publish_key(self):
log.info('%s => Publish key', self._account)
key = self._pgp.export_key(self._fingerprint)
date = time.strftime(
'%Y-%m-%dT%H:%M:%SZ', time.gmtime(self._date))
pubkey_node = Node('pubkey', attrs={'xmlns': NS_OPENPGP,
'date': date})
data = pubkey_node.addChild('data')
data.addData(b64encode(key).decode('utf8'))
node = '%s:%s' % (NS_OPENPGP_PUBLIC_KEYS, self._fingerprint)
self._con.get_module('PubSub').send_pb_publish(
self.own_jid, node, pubkey_node,
id_='current', cb=self._public_result)
def _publish_key_list(self, keylist=None):
if keylist is None:
keylist = [Key(self._fingerprint, self._date)]
log.info('%s => Publish keys list', self._account)
self._con.get_module('PGPKeylist').send(keylist)
def _public_result(self, con, stanza):
if not isResultNode(stanza):
log.error('%s => Publishing failed: %s',
self._account, stanza.getError())
def _query_public_key(self, jid, fingerprint):
log.info('%s => Fetch public key %s - %s',
self._account, fingerprint, jid)
node = '%s:%s' % (NS_OPENPGP_PUBLIC_KEYS, fingerprint)
self._con.get_module('PubSub').send_pb_retrieve(
jid, node, cb=self._public_key_received, fingerprint=fingerprint)
def _public_key_received(self, con, stanza, fingerprint):
if not isResultNode(stanza):
log.error('%s => Public Key not found: %s',
self._account, stanza.getError())
return
pubkey = util.unpack_public_key(stanza, fingerprint)
if pubkey is None:
log.warning('Invalid public key received:\n%s', stanza)
return
jid = stanza.getFrom().getStripped()
result = self._pgp.import_key(pubkey, jid)
if result is not None:
self._contacts.set_public_key(jid, fingerprint)
def query_key_list(self, jid=None):
if jid is None:
jid = self.own_jid
log.info('%s => Fetch keys list %s', self._account, jid)
self._con.get_module('PubSub').send_pb_retrieve(
jid, NS_OPENPGP_PUBLIC_KEYS,
cb=self._query_key_list_result)
def _query_key_list_result(self, con, stanza):
from_jid = stanza.getFrom()
if from_jid is None:
from_jid = self.own_jid
else:
from_jid = from_jid.getStripped()
if not isResultNode(stanza):
log.error('%s => Keys list query failed: %s',
self._account, stanza.getError())
if from_jid == self.own_jid and self._fingerprint is not None:
self._publish_key_list()
return
from_jid = stanza.getFrom()
if from_jid is None:
from_jid = self.own_jid
else:
from_jid = from_jid.getStripped()
keylist = util.unpack_public_key_list(stanza, from_jid)
self.key_list_received(keylist, from_jid)
def key_list_received(self, keylist, from_jid):
if keylist is None:
log.warning('Invalid keys list received')
if from_jid == self.own_jid and self._fingerprint is not None:
self._publish_key_list()
return
if not keylist:
log.warning('%s => Empty keys list received from %s',
self._account, from_jid)
self._contacts.process_keylist(self.own_jid, keylist)
if from_jid == self.own_jid and self._fingerprint is not None:
self._publish_key_list()
return
if from_jid == self.own_jid:
log.info('Received own keys list')
for key in keylist:
log.info(key.fingerprint)
for key in keylist:
# Check if own fingerprint is published
if key.fingerprint == self._fingerprint:
log.info('Own key found in keys list')
return
log.info('Own key not published')
if self._fingerprint is not None:
keylist.append(Key(self._fingerprint, None))
self._publish_key_list(keylist)
return
missing_pub_keys = self._contacts.process_keylist(from_jid, keylist)
for key in keylist:
log.info(key.fingerprint)
for fingerprint in missing_pub_keys:
self._query_public_key(from_jid, fingerprint)
def decrypt_message(self, obj, callback):
if obj.encrypted:
# Another Plugin already decrypted the message
return
if obj.name == 'message-received':
enc_tag = obj.stanza.getTag('openpgp', namespace=NS_OPENPGP)
jid = obj.jid
else:
enc_tag = obj.message.getTag('openpgp', namespace=NS_OPENPGP)
jid = obj.with_
if enc_tag is None:
return
log.info('Received OpenPGP message from: %s', jid)
b64encode_payload = enc_tag.getData()
encrypted_payload = b64decode(b64encode_payload)
try:
decrypted_payload = self._pgp.decrypt(encrypted_payload)
except DecryptionFailed as error:
log.warning(error)
return
signcrypt = Node(node=decrypted_payload)
signcrypt_jid = signcrypt.getTagAttr('to', 'jid')
if self.own_jid != signcrypt_jid:
log.warning('signcrypt "to" attr %s != %s',
self.own_jid, signcrypt_jid)
log.debug(signcrypt)
return
payload = signcrypt.getTag('payload')
body = None
if obj.name == 'message-received':
obj.stanza.delChild(enc_tag)
for node in payload.getChildren():
if node.name == 'body':
body = node.getData()
obj.stanza.setTagData('body', body)
else:
obj.stanza.addChild(node=node)
else:
obj.msg_.delChild(enc_tag)
for node in payload.getChildren():
if node.name == 'body':
body = node.getData()
obj.msg_.setTagData('body', node.getData())
else:
obj.msg_.addChild(node=node)
if body:
obj.msgtxt = body
obj.encrypted = ENCRYPTION_NAME
callback(obj)
def encrypt_message(self, obj, callback):
keys = self._contacts.get_keys(obj.jid)
if not keys:
# TODO: this should never happen in theory
log.error('Droping stanza to %s, because we have no key', obj.jid)
return
keys += self._contacts.get_keys(self.own_jid)
keys += [Key(self._fingerprint, None)]
payload = util.create_signcrypt_node(obj)
encrypted_payload, error = self._pgp.encrypt(payload, keys)
if error:
log.error('Error: %s', error)
app.nec.push_incoming_event(
MessageNotSentEvent(
None, conn=self._con, jid=obj.jid, message=obj.message,
error=error, time_=time.time()))
return
util.create_openpgp_message(obj, encrypted_payload)
obj.encrypted = ENCRYPTION_NAME
self.print_msg_to_log(obj.msg_iq)
callback(obj)
@staticmethod
def print_msg_to_log(stanza):
""" Prints a stanza in a fancy way to the log """
log.debug('-'*15)
stanzastr = '\n' + stanza.__str__(fancy=True)
stanzastr = stanzastr[0:-1]
log.debug(stanzastr)
log.debug('-'*15)
def get_keys(self, jid=None, only_trusted=True):
if jid is None:
jid = self.own_jid
return self._contacts.get_keys(jid, only_trusted=only_trusted)
def clear_fingerprints(self):
self._publish_key_list()
def cleanup(self):
self._storage.cleanup()
self._pgp = None
self._contacts = None
def get_instance(*args, **kwargs):
return OpenPGP(*args, **kwargs), 'OpenPGP'