openwebrx-clone/owrx/receiverid.py
2020-06-11 20:55:05 +02:00

82 lines
2.4 KiB
Python

import re
import logging
import hashlib
import hmac
from datetime import datetime
from owrx.config import Config
logger = logging.getLogger(__name__)
keyRegex = re.compile("^([a-zA-Z]+)-([0-9a-f]{32})-([0-9a-f]{64})$")
keyChallengeRegex = re.compile("^([a-zA-Z]+)-([0-9a-f]{32})-([0-9a-f]{32})$")
headerRegex = re.compile("^ReceiverId (.*)$")
class KeyException(Exception):
pass
class Key(object):
def __init__(self, keyString):
matches = keyRegex.match(keyString)
if not matches:
raise KeyException("invalid key format")
self.source = matches.group(1)
self.id = matches.group(2)
self.secret = matches.group(3)
class KeyChallenge(object):
def __init__(self, challengeString):
matches = keyChallengeRegex.match(challengeString)
if not matches:
raise KeyException("invalid key challenge format")
self.source = matches.group(1)
self.id = matches.group(2)
self.challenge = matches.group(3)
class KeyResponse(object):
def __str__(self):
return "TODO"
class ReceiverId(object):
@staticmethod
def getResponseHeader(requestHeader):
matches = headerRegex.match(requestHeader)
if not matches:
raise KeyException("invalid authorization header")
challenge = KeyChallenge(matches.group(1))
key = ReceiverId.findKey(challenge)
if key is None:
return {}
time, signature = ReceiverId.signChallenge(challenge, key)
return {
"Signature": signature,
"Time": time,
}
@staticmethod
def findKey(challenge):
def parseKey(keyString):
try:
return Key(keyString)
except KeyException as e:
logger.error(e)
keys = [parseKey(keyString) for keyString in Config.get()['receiver_keys']]
keys = [key for key in keys if key is not None]
matching_keys = [key for key in keys if key.source == challenge.source and key.id == challenge.id]
if matching_keys:
return matching_keys[0]
return None
@staticmethod
def signChallenge(challenge, key):
now = datetime.utcnow().isoformat()
m = hmac.new(bytes.fromhex(key.secret), digestmod=hashlib.sha256)
m.update(bytes.fromhex(challenge.challenge))
m.update(now.encode('utf8'))
return now, m.hexdigest()