107 lines
3.9 KiB
Python
107 lines
3.9 KiB
Python
"""passbook policy engine"""
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from multiprocessing import Pipe
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from multiprocessing.connection import Connection
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from typing import List, Tuple
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from django.core.cache import cache
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from django.http import HttpRequest
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from structlog import get_logger
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from passbook.core.models import Policy, User
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from passbook.policies.process import PolicyProcess, cache_key
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from passbook.policies.struct import PolicyRequest, PolicyResult
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LOGGER = get_logger()
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class PolicyProcessInfo:
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"""Dataclass to hold all information and communication channels to a process"""
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process: PolicyProcess
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connection: Connection
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result: PolicyResult = None
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policy: Policy
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def __init__(self, process: PolicyProcess, connection: Connection, policy: Policy):
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self.process = process
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self.connection = connection
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self.policy = policy
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class PolicyEngine:
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"""Orchestrate policy checking, launch tasks and return result"""
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policies: List[Policy] = []
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__request: HttpRequest
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__user: User
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__processes: List[PolicyProcessInfo] = []
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def __init__(self, policies, user: User = None, request: HttpRequest = None):
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self.policies = policies
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self.__request = request
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self.__user = user
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self.__processes = []
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def for_user(self, user: User) -> 'PolicyEngine':
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"""Check policies for user"""
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self.__user = user
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return self
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def with_request(self, request: HttpRequest) -> 'PolicyEngine':
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"""Set request"""
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self.__request = request
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return self
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def _select_subclasses(self) -> List[Policy]:
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"""Make sure all Policies are their respective classes"""
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return Policy.objects \
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.filter(pk__in=[x.pk for x in self.policies]) \
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.select_subclasses() \
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.order_by('order')
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def build(self) -> 'PolicyEngine':
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"""Build task group"""
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if not self.__user:
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raise ValueError("User not set.")
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cached_policies = []
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request = PolicyRequest(self.__user)
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request.http_request = self.__request
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for policy in self._select_subclasses():
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cached_policy = cache.get(cache_key(policy, self.__user), None)
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if cached_policy:
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LOGGER.debug("Taking result from cache", policy=policy)
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cached_policies.append(cached_policy)
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else:
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LOGGER.debug("Evaluating policy", policy=policy)
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our_end, task_end = Pipe(False)
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task = PolicyProcess(policy, request, task_end)
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LOGGER.debug("Starting Process", for_policy=policy)
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task.start()
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self.__processes.append(PolicyProcessInfo(process=task,
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connection=our_end, policy=policy))
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# If all policies are cached, we have an empty list here.
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for proc_info in self.__processes:
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proc_info.process.join(proc_info.policy.timeout)
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# Only call .recv() if no result is saved, otherwise we just deadlock here
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if not proc_info.result:
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proc_info.result = proc_info.connection.recv()
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return self
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@property
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def result(self) -> Tuple[bool, List[str]]:
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"""Get policy-checking result"""
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messages: List[str] = []
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for proc_info in self.__processes:
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# passing = (policy_action == Policy.ACTION_ALLOW and policy_result) or \
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# (policy_action == Policy.ACTION_DENY and not policy_result)
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LOGGER.debug("Result", passing=proc_info.result.passing)
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if proc_info.result.messages:
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messages += proc_info.result.messages
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if not proc_info.result.passing:
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return False, messages
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return True, messages
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@property
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def passing(self) -> bool:
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"""Only get true/false if user passes"""
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return self.result[0]
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