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authentik/passbook/providers/saml/views.py
Jens Langhammer a5bfef9b6b providers/saml: fix leftover data in session, fix IdP initiated login
move can_handle calls to binding endpoints (/login/ and /login/initiate/), so that /login/authorize/ works either way, can clean up the session and audit
2020-02-24 17:34:52 +01:00

294 lines
11 KiB
Python

"""passbook SAML IDP Views"""
from typing import Optional
from django.contrib.auth import logout
from django.contrib.auth.mixins import AccessMixin
from django.core.exceptions import ValidationError
from django.core.validators import URLValidator
from django.http import HttpRequest, HttpResponse
from django.shortcuts import get_object_or_404, redirect, render, reverse
from django.utils.datastructures import MultiValueDictKeyError
from django.utils.decorators import method_decorator
from django.utils.html import mark_safe
from django.utils.translation import gettext as _
from django.views import View
from django.views.decorators.csrf import csrf_exempt
from signxml.util import strip_pem_header
from structlog import get_logger
from passbook.audit.models import Event, EventAction
from passbook.core.models import Application, Provider
from passbook.lib.utils.template import render_to_string
from passbook.lib.views import bad_request_message
from passbook.policies.engine import PolicyEngine
from passbook.providers.saml.exceptions import CannotHandleAssertion
from passbook.providers.saml.models import SAMLProvider
from passbook.providers.saml.processors.types import SAMLResponseParams
LOGGER = get_logger()
URL_VALIDATOR = URLValidator(schemes=("http", "https"))
SESSION_KEY_SAML_REQUEST = "SAMLRequest"
SESSION_KEY_SAML_RESPONSE = "SAMLResponse"
SESSION_KEY_RELAY_STATE = "RelayState"
SESSION_KEY_PARAMS = "SAMLParams"
class AccessRequiredView(AccessMixin, View):
"""Mixin class for Views using a provider instance"""
_provider: Optional[SAMLProvider] = None
@property
def provider(self) -> SAMLProvider:
"""Get provider instance"""
if not self._provider:
application = get_object_or_404(
Application, slug=self.kwargs["application"]
)
provider: SAMLProvider = get_object_or_404(
SAMLProvider, pk=application.provider_id
)
self._provider = provider
return self._provider
return self._provider
def _has_access(self) -> bool:
"""Check if user has access to application"""
policy_engine = PolicyEngine(
self.provider.application.policies.all(), self.request.user, self.request
)
policy_engine.build()
passing = policy_engine.passing
LOGGER.debug(
"saml_has_access",
user=self.request.user,
app=self.provider.application,
passing=passing,
)
return passing
def dispatch(self, request: HttpRequest, *args, **kwargs) -> HttpResponse:
if not request.user.is_authenticated:
return self.handle_no_permission()
if not self._has_access():
return render(
request,
"login/denied.html",
{"title": _("You don't have access to this application"),},
)
return super().dispatch(request, *args, **kwargs)
class LoginBeginView(AccessRequiredView):
"""Receives a SAML 2.0 AuthnRequest from a Service Provider and
stores it in the session prior to enforcing login."""
@method_decorator(csrf_exempt)
def dispatch(self, request: HttpRequest, application: str) -> HttpResponse:
if request.method == "POST":
source = request.POST
else:
source = request.GET
# Store these values now, because Django's login cycle won't preserve them.
try:
request.session[SESSION_KEY_SAML_REQUEST] = source[SESSION_KEY_SAML_REQUEST]
except (KeyError, MultiValueDictKeyError):
return bad_request_message(request, "The SAML request payload is missing.")
request.session[SESSION_KEY_RELAY_STATE] = source.get(
SESSION_KEY_RELAY_STATE, ""
)
try:
self.provider.processor.can_handle(request)
params = self.provider.processor.generate_response()
request.session[SESSION_KEY_PARAMS] = params
except CannotHandleAssertion as exc:
LOGGER.error(exc)
did_you_mean_link = request.build_absolute_uri(
reverse(
"passbook_providers_saml:saml-login-initiate",
kwargs={"application": application},
)
)
did_you_mean_message = (
f" Did you mean to go <a href='{did_you_mean_link}'>here</a>?"
)
return bad_request_message(
request, mark_safe(str(exc) + did_you_mean_message)
)
return redirect(
reverse(
"passbook_providers_saml:saml-login-authorize",
kwargs={"application": application},
)
)
class InitiateLoginView(AccessRequiredView):
"""IdP-initiated Login"""
def get(self, request: HttpRequest, application: str) -> HttpResponse:
"""Initiates an IdP-initiated link to a simple SP resource/target URL."""
self.provider.processor.is_idp_initiated = True
self.provider.processor.init_deep_link(request)
params = self.provider.processor.generate_response()
request.session[SESSION_KEY_SAML_RESPONSE] = params
return redirect(
reverse(
"passbook_providers_saml:saml-login-authorize",
kwargs={"application": application},
)
)
class AuthorizeView(AccessRequiredView):
"""Ask the user for authorization to continue to the SP.
Presents a SAML 2.0 Assertion for POSTing back to the Service Provider."""
def get(self, request: HttpRequest, application: str) -> HttpResponse:
"""Handle get request, i.e. render form"""
# User access gets checked in dispatch
# Otherwise we generate the IdP initiated session
try:
# application.skip_authorization is set so we directly redirect the user
if self.provider.application.skip_authorization:
LOGGER.debug("skipping authz", application=self.provider.application)
return self.post(request, application)
return render(
request,
"saml/idp/login.html",
{"provider": self.provider, "title": "Authorize Application",},
)
except KeyError:
return bad_request_message(request, "Missing SAML Payload")
# pylint: disable=unused-argument
def post(self, request: HttpRequest, application: str) -> HttpResponse:
"""Handle post request, return back to ACS"""
# User access gets checked in dispatch
# we get here when skip_authorization is True, and after the user accepted
# the authorization form
# Log Application Authorization
Event.new(
EventAction.AUTHORIZE_APPLICATION,
authorized_application=self.provider.application,
skipped_authorization=self.provider.application.skip_authorization,
).from_http(self.request)
self.request.session.pop(SESSION_KEY_SAML_REQUEST, None)
self.request.session.pop(SESSION_KEY_SAML_RESPONSE, None)
self.request.session.pop(SESSION_KEY_RELAY_STATE, None)
response: SAMLResponseParams = self.request.session.pop(SESSION_KEY_PARAMS)
return render(
self.request,
"saml/idp/autosubmit_form.html",
{
"url": response.acs_url,
"attrs": {
"ACSUrl": response.acs_url,
SESSION_KEY_SAML_RESPONSE: response.saml_response,
SESSION_KEY_RELAY_STATE: response.relay_state,
},
},
)
@method_decorator(csrf_exempt, name="dispatch")
class LogoutView(AccessRequiredView):
"""Allows a non-SAML 2.0 URL to log out the user and
returns a standard logged-out page. (SalesForce and others use this method,
though it's technically not SAML 2.0)."""
# pylint: disable=unused-argument
def get(self, request: HttpRequest, application: str) -> HttpResponse:
"""Perform logout"""
logout(request)
redirect_url = request.GET.get("redirect_to", "")
try:
URL_VALIDATOR(redirect_url)
except ValidationError:
pass
else:
return redirect(redirect_url)
return render(request, "saml/idp/logged_out.html")
@method_decorator(csrf_exempt, name="dispatch")
class SLOLogout(AccessRequiredView):
"""Receives a SAML 2.0 LogoutRequest from a Service Provider,
logs out the user and returns a standard logged-out page."""
# pylint: disable=unused-argument
def post(self, request: HttpRequest, application: str) -> HttpResponse:
"""Perform logout"""
request.session[SESSION_KEY_SAML_REQUEST] = request.POST[
SESSION_KEY_SAML_REQUEST
]
# TODO: Parse SAML LogoutRequest from POST data, similar to login_process().
# TODO: Modify the base processor to handle logouts?
# TODO: Combine this with login_process(), since they are so very similar?
# TODO: Format a LogoutResponse and return it to the browser.
# XXX: For now, simply log out without validating the request.
logout(request)
return render(request, "saml/idp/logged_out.html")
class DescriptorDownloadView(AccessRequiredView):
"""Replies with the XML Metadata IDSSODescriptor."""
@staticmethod
def get_metadata(request: HttpRequest, provider: SAMLProvider) -> str:
"""Return rendered XML Metadata"""
entity_id = provider.issuer
slo_url = request.build_absolute_uri(
reverse(
"passbook_providers_saml:saml-logout",
kwargs={"application": provider.application.slug},
)
)
sso_post_url = request.build_absolute_uri(
reverse(
"passbook_providers_saml:saml-login",
kwargs={"application": provider.application.slug},
)
)
pubkey = strip_pem_header(provider.signing_cert.replace("\r", "")).replace(
"\n", ""
)
subject_format = provider.processor.subject_format
ctx = {
"entity_id": entity_id,
"cert_public_key": pubkey,
"slo_url": slo_url,
# Currently, the same endpoint accepts POST and REDIRECT
"sso_post_url": sso_post_url,
"sso_redirect_url": sso_post_url,
"subject_format": subject_format,
}
return render_to_string("saml/xml/metadata.xml", ctx)
# pylint: disable=unused-argument
def get(self, request: HttpRequest, application: str) -> HttpResponse:
"""Replies with the XML Metadata IDSSODescriptor."""
try:
metadata = DescriptorDownloadView.get_metadata(request, self.provider)
except Provider.application.RelatedObjectDoesNotExist: # pylint: disable=no-member
return bad_request_message(
request, "Provider is not assigned to an application."
)
else:
response = HttpResponse(metadata, content_type="application/xml")
response[
"Content-Disposition"
] = f'attachment; filename="{self.provider.name}_passbook_meta.xml"'
return response