mirror of
https://git.anonymousland.org/anonymousland/synapse-product.git
synced 2024-12-29 21:56:11 -05:00
89 lines
3.1 KiB
Python
89 lines
3.1 KiB
Python
# Copyright 2020 Quentin Gliech
|
|
# Copyright 2021 The Matrix.org Foundation C.I.C.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
"""Utilities for manipulating macaroons"""
|
|
|
|
from typing import Callable, Optional
|
|
|
|
import pymacaroons
|
|
from pymacaroons.exceptions import MacaroonVerificationFailedException
|
|
|
|
|
|
def get_value_from_macaroon(macaroon: pymacaroons.Macaroon, key: str) -> str:
|
|
"""Extracts a caveat value from a macaroon token.
|
|
|
|
Checks that there is exactly one caveat of the form "key = <val>" in the macaroon,
|
|
and returns the extracted value.
|
|
|
|
Args:
|
|
macaroon: the token
|
|
key: the key of the caveat to extract
|
|
|
|
Returns:
|
|
The extracted value
|
|
|
|
Raises:
|
|
MacaroonVerificationFailedException: if there are conflicting values for the
|
|
caveat in the macaroon, or if the caveat was not found in the macaroon.
|
|
"""
|
|
prefix = key + " = "
|
|
result: Optional[str] = None
|
|
for caveat in macaroon.caveats:
|
|
if not caveat.caveat_id.startswith(prefix):
|
|
continue
|
|
|
|
val = caveat.caveat_id[len(prefix) :]
|
|
|
|
if result is None:
|
|
# first time we found this caveat: record the value
|
|
result = val
|
|
elif val != result:
|
|
# on subsequent occurrences, raise if the value is different.
|
|
raise MacaroonVerificationFailedException(
|
|
"Conflicting values for caveat " + key
|
|
)
|
|
|
|
if result is not None:
|
|
return result
|
|
|
|
# If the caveat is not there, we raise a MacaroonVerificationFailedException.
|
|
# Note that it is insecure to generate a macaroon without all the caveats you
|
|
# might need (because there is nothing stopping people from adding extra caveats),
|
|
# so if the caveat isn't there, something odd must be going on.
|
|
raise MacaroonVerificationFailedException("No %s caveat in macaroon" % (key,))
|
|
|
|
|
|
def satisfy_expiry(v: pymacaroons.Verifier, get_time_ms: Callable[[], int]) -> None:
|
|
"""Make a macaroon verifier which accepts 'time' caveats
|
|
|
|
Builds a caveat verifier which will accept unexpired 'time' caveats, and adds it to
|
|
the given macaroon verifier.
|
|
|
|
Args:
|
|
v: the macaroon verifier
|
|
get_time_ms: a callable which will return the timestamp after which the caveat
|
|
should be considered expired. Normally the current time.
|
|
"""
|
|
|
|
def verify_expiry_caveat(caveat: str) -> bool:
|
|
time_msec = get_time_ms()
|
|
prefix = "time < "
|
|
if not caveat.startswith(prefix):
|
|
return False
|
|
expiry = int(caveat[len(prefix) :])
|
|
return time_msec < expiry
|
|
|
|
v.satisfy_general(verify_expiry_caveat)
|