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# Copyright (C) 2018 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of nbxmpp.
#
# This program 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; 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; If not, see <http://www.gnu.org/licenses/>.
from typing import Optional
import logging
import hashlib
from nbxmpp.simplexml import Node
from nbxmpp.namespaces import Namespace
from nbxmpp.structs import BobData
from nbxmpp.util import b64decode
log = logging.getLogger('nbxmpp.m.bob')
def parse_bob_data(stanza: Node) -> Optional[BobData]:
data_node = stanza.getTag('data', namespace=Namespace.BOB)
if data_node is None:
return None
cid = data_node.getAttr('cid')
type_ = data_node.getAttr('type')
max_age = data_node.getAttr('max-age')
if max_age is not None:
try:
max_age = int(max_age)
except Exception:
log.exception(stanza)
return None
if cid is None or type_ is None:
log.warning('Invalid data node (no cid or type attr): %s', stanza)
return None
try:
algo_hash = cid.split('@')[0]
algo, hash_ = algo_hash.split('+')
except Exception:
log.exception('Invalid cid: %s', stanza)
return None
bob_data = data_node.getData()
if not bob_data:
log.warning('No bob data found: %s', stanza)
return None
try:
bob_data = b64decode(bob_data)
except Exception:
log.warning('Unable to decode data')
log.exception(stanza)
return None
try:
sha = hashlib.new(algo)
except ValueError as error:
log.warning(stanza)
log.warning(error)
return None
sha.update(bob_data)
if sha.hexdigest() != hash_:
log.warning('Invalid hash: %s', stanza)
return None
return BobData(algo=algo,
hash_=hash_,
max_age=max_age,
data=bob_data,
cid=cid,
type=type_)
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