86 lines
3.0 KiB
Python
86 lines
3.0 KiB
Python
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"""passbook saml source processor"""
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from typing import Optional
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from xml.etree.ElementTree import Element
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from defusedxml import ElementTree
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from django.http import HttpRequest
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from signxml import XMLVerifier
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from structlog import get_logger
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from passbook.core.models import User
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from passbook.providers.saml.utils.encoding import decode_base64_and_inflate
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from passbook.sources.saml.exceptions import (
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MissingSAMLResponse,
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UnsupportedNameIDFormat,
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)
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from passbook.sources.saml.models import SAMLSource
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LOGGER = get_logger()
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class Processor:
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"""SAML Response Processor"""
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_source: SAMLSource
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_root: Element
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_root_xml: str
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def __init__(self, source: SAMLSource):
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self._source = source
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def parse(self, request: HttpRequest):
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"""Check if `request` contains SAML Response data, parse and validate it."""
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# First off, check if we have any SAML Data at all.
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raw_response = request.POST.get("SAMLResponse", None)
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if not raw_response:
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raise MissingSAMLResponse("Request does not contain 'SAMLResponse'")
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# relay_state = request.POST.get('RelayState', None)
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# Check if response is compressed, b64 decode it
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self._root_xml = response = decode_base64_and_inflate(raw_response)
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self._root = ElementTree.fromstring(self._root_xml)
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# Verify signed XML
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self._verify_signed()
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def _verify_signed(self):
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"""Verify SAML Response's Signature"""
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verifier = XMLVerifier()
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verifier.verify(self._root_xml, x509_cert=self._source.signing_cert)
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def _get_email(self) -> Optional[str]:
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"""
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Returns the email out of the response.
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At present, response must pass the email address as the Subject, eg.:
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<saml:Subject>
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<saml:NameID Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress"
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SPNameQualifier=""
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>email@example.com</saml:NameID>
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"""
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assertion = self._root.find("{urn:oasis:names:tc:SAML:2.0:assertion}Assertion")
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subject = assertion.find("{urn:oasis:names:tc:SAML:2.0:assertion}Subject")
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name_id = subject.find("{urn:oasis:names:tc:SAML:2.0:assertion}NameID")
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name_id_format = name_id.attrib["Format"]
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if name_id_format != "urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress":
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raise UnsupportedNameIDFormat(
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f"Assertion contains NameID with unsupported format {name_id_format}."
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)
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return name_id.text
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def get_user(self) -> User:
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"""
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Gets info out of the response and locally logs in this user.
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May create a local user account first.
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Returns the user object that was created.
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"""
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email = self._get_email()
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try:
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user = User.objects.get(email=email)
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except User.DoesNotExist:
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user = User.objects.create_user(username=email, email=email)
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# TODO: Property Mappings
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user.set_unusable_password()
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user.save()
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return user
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