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# Copyright (C) 2018 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of nbxmpp.
#
# SPDX-License-Identifier: GPL-3.0-or-later
import hashlib
import logging
from nbxmpp.namespaces import Namespace
from nbxmpp.simplexml import Node
from nbxmpp.structs import BobData
from nbxmpp.util import b64decode
log = logging.getLogger("nbxmpp.m.bob")
def parse_bob_data(stanza: Node) -> BobData | None:
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
assert max_age is not 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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