73 lines
2.8 KiB
Python
73 lines
2.8 KiB
Python
"""passbook expression policy evaluator"""
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from ipaddress import ip_address, ip_network
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from typing import List
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from django.http import HttpRequest
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from structlog import get_logger
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from passbook.flows.planner import PLAN_CONTEXT_SSO
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from passbook.lib.expression.evaluator import BaseEvaluator
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from passbook.lib.utils.http import get_client_ip
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from passbook.policies.types import PolicyRequest, PolicyResult
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LOGGER = get_logger()
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class PolicyEvaluator(BaseEvaluator):
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"""Validate and evaluate python-based expressions"""
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_messages: List[str]
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def __init__(self, policy_name: str):
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super().__init__()
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self._messages = []
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self._context["pb_message"] = self.expr_func_message
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self._context["ip_address"] = ip_address
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self._context["ip_network"] = ip_network
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self._filename = policy_name or "PolicyEvaluator"
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def expr_func_message(self, message: str):
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"""Wrapper to append to messages list, which is returned with PolicyResult"""
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self._messages.append(message)
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def set_policy_request(self, request: PolicyRequest):
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"""Update context based on policy request (if http request is given, update that too)"""
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# update website/docs/policies/expression.md
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self._context["pb_is_sso_flow"] = request.context.get(PLAN_CONTEXT_SSO, False)
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if request.http_request:
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self.set_http_request(request.http_request)
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self._context["request"] = request
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self._context["context"] = request.context
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def set_http_request(self, request: HttpRequest):
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"""Update context based on http request"""
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# update website/docs/policies/expression.md
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self._context["pb_client_ip"] = ip_address(
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get_client_ip(request) or "255.255.255.255"
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)
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self._context["request"] = request
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def evaluate(self, expression_source: str) -> PolicyResult:
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"""Parse and evaluate expression. Policy is expected to return a truthy object.
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Messages can be added using 'do pb_message()'."""
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try:
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result = super().evaluate(expression_source)
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except (ValueError, SyntaxError) as exc:
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return PolicyResult(False, str(exc))
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except Exception as exc: # pylint: disable=broad-except
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LOGGER.warning("Expression error", exc=exc)
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return PolicyResult(False, str(exc))
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else:
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policy_result = PolicyResult(False)
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policy_result.messages = tuple(self._messages)
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if result is None:
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LOGGER.warning(
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"Expression policy returned None",
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src=expression_source,
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req=self._context,
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)
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policy_result.passing = False
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if result:
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policy_result.passing = bool(result)
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return policy_result
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