synapse/synapse/config/key.py
Richard van der Hoff 7216c76654 Improve error handling for missing files (#2551)
`os.path.exists` doesn't allow us to distinguish between permissions errors and
the path actually not existing, which repeatedly confuses people. It also means
that we try to overwrite existing key files, which is super-confusing. (cf
issues #2455, #2379). Use os.stat instead.

Also, don't recomemnd the the use of --generate-config, which screws everything
up if you're using debian (cf #2455).
2017-10-17 14:46:17 +01:00

161 lines
6.1 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2015, 2016 OpenMarket Ltd
#
# 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.
from ._base import Config, ConfigError
from synapse.util.stringutils import random_string
from signedjson.key import (
generate_signing_key, is_signing_algorithm_supported,
decode_signing_key_base64, decode_verify_key_bytes,
read_signing_keys, write_signing_keys, NACL_ED25519
)
from unpaddedbase64 import decode_base64
from synapse.util.stringutils import random_string_with_symbols
import os
import hashlib
import logging
logger = logging.getLogger(__name__)
class KeyConfig(Config):
def read_config(self, config):
self.signing_key = self.read_signing_key(config["signing_key_path"])
self.old_signing_keys = self.read_old_signing_keys(
config["old_signing_keys"]
)
self.key_refresh_interval = self.parse_duration(
config["key_refresh_interval"]
)
self.perspectives = self.read_perspectives(
config["perspectives"]
)
self.macaroon_secret_key = config.get(
"macaroon_secret_key", self.registration_shared_secret
)
if not self.macaroon_secret_key:
# Unfortunately, there are people out there that don't have this
# set. Lets just be "nice" and derive one from their secret key.
logger.warn("Config is missing missing macaroon_secret_key")
seed = self.signing_key[0].seed
self.macaroon_secret_key = hashlib.sha256(seed)
self.expire_access_token = config.get("expire_access_token", False)
def default_config(self, config_dir_path, server_name, is_generating_file=False,
**kwargs):
base_key_name = os.path.join(config_dir_path, server_name)
if is_generating_file:
macaroon_secret_key = random_string_with_symbols(50)
else:
macaroon_secret_key = None
return """\
macaroon_secret_key: "%(macaroon_secret_key)s"
# Used to enable access token expiration.
expire_access_token: False
## Signing Keys ##
# Path to the signing key to sign messages with
signing_key_path: "%(base_key_name)s.signing.key"
# The keys that the server used to sign messages with but won't use
# to sign new messages. E.g. it has lost its private key
old_signing_keys: {}
# "ed25519:auto":
# # Base64 encoded public key
# key: "The public part of your old signing key."
# # Millisecond POSIX timestamp when the key expired.
# expired_ts: 123456789123
# How long key response published by this server is valid for.
# Used to set the valid_until_ts in /key/v2 APIs.
# Determines how quickly servers will query to check which keys
# are still valid.
key_refresh_interval: "1d" # 1 Day.
# The trusted servers to download signing keys from.
perspectives:
servers:
"matrix.org":
verify_keys:
"ed25519:auto":
key: "Noi6WqcDj0QmPxCNQqgezwTlBKrfqehY1u2FyWP9uYw"
""" % locals()
def read_perspectives(self, perspectives_config):
servers = {}
for server_name, server_config in perspectives_config["servers"].items():
for key_id, key_data in server_config["verify_keys"].items():
if is_signing_algorithm_supported(key_id):
key_base64 = key_data["key"]
key_bytes = decode_base64(key_base64)
verify_key = decode_verify_key_bytes(key_id, key_bytes)
servers.setdefault(server_name, {})[key_id] = verify_key
return servers
def read_signing_key(self, signing_key_path):
signing_keys = self.read_file(signing_key_path, "signing_key")
try:
return read_signing_keys(signing_keys.splitlines(True))
except Exception as e:
raise ConfigError(
"Error reading signing_key: %s" % (str(e))
)
def read_old_signing_keys(self, old_signing_keys):
keys = {}
for key_id, key_data in old_signing_keys.items():
if is_signing_algorithm_supported(key_id):
key_base64 = key_data["key"]
key_bytes = decode_base64(key_base64)
verify_key = decode_verify_key_bytes(key_id, key_bytes)
verify_key.expired_ts = key_data["expired_ts"]
keys[key_id] = verify_key
else:
raise ConfigError(
"Unsupported signing algorithm for old key: %r" % (key_id,)
)
return keys
def generate_files(self, config):
signing_key_path = config["signing_key_path"]
if not self.path_exists(signing_key_path):
with open(signing_key_path, "w") as signing_key_file:
key_id = "a_" + random_string(4)
write_signing_keys(
signing_key_file, (generate_signing_key(key_id),),
)
else:
signing_keys = self.read_file(signing_key_path, "signing_key")
if len(signing_keys.split("\n")[0].split()) == 1:
# handle keys in the old format.
key_id = "a_" + random_string(4)
key = decode_signing_key_base64(
NACL_ED25519, key_id, signing_keys.split("\n")[0]
)
with open(signing_key_path, "w") as signing_key_file:
write_signing_keys(
signing_key_file, (key,),
)