Add SLO support from federated CAS

cas_server/federate.py

@@ -12,7 +12,11 @@
 from .default_settings import settings
 
 from .cas import CASClient
-from .models import FederatedUser
+from .models import FederatedUser, FederateSLO, User
+
+from importlib import import_module
+
+SessionStore = import_module(settings.SESSION_ENGINE).SessionStore
 
 
 class CASFederateValidateUser(object):
@@ -68,3 +72,33 @@ class CASFederateValidateUser(object):
             return True
         else:
             return False
+
+    def register_slo(self, username, session_key, ticket):
+        FederateSLO.objects.create(
+            username=username,
+            session_key=session_key,
+            ticket=ticket
+        )
+
+    def clean_sessions(self, logout_request):
+        try:
+            SLOs = self.client.get_saml_slos(logout_request)
+        except NameError:
+            SLOs = []
+        for slo in SLOs:
+            try:
+                for federate_slo in FederateSLO.objects.filter(ticket=slo.text):
+                    session = SessionStore(session_key=federate_slo.session_key)
+                    session.flush()
+                    try:
+                        user = User.objects.get(
+                            username=federate_slo.username,
+                            session_key=federate_slo.session_key
+                        )
+                        user.logout()
+                        user.delete()
+                    except User.DoesNotExist:
+                        pass
+                    federate_slo.delete()
+            except FederateSLO.DoesNotExist:
+                pass

cas_server/management/commands/cas_clean_federate.py

@@ -16,6 +16,8 @@ class Command(BaseCommand):
         federated_users = models.FederatedUser.objects.filter(
             last_update__lt=(timezone.now() - timedelta(seconds=settings.CAS_TICKET_TIMEOUT))
         )
+        known_users = {user.username for user in models.User.objects.all()}
         for user in federated_users:
-            if not models.User.objects.filter(username='%s@%s' % (user.username, user.provider)):
+            if not ('%s@%s' % (user.username, user.provider)) in known_users:
                 user.delete()
+        models.FederateSLO.clean_deleted_sessions()

cas_server/migrations/0006_auto_20160623_1516.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.7 on 2016-06-23 15:16
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cas_server', '0005_auto_20160616_1018'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='FederateSLO',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('username', models.CharField(max_length=30)),
+                ('session_key', models.CharField(blank=True, max_length=40, null=True)),
+                ('ticket', models.CharField(max_length=255)),
+            ],
+        ),
+        migrations.AlterUniqueTogether(
+            name='federateslo',
+            unique_together=set([('username', 'session_key')]),
+        ),
+    ]

cas_server/models.py

@@ -48,6 +48,25 @@ class FederatedUser(models.Model):
         return u"%s@%s" % (self.username, self.provider)
 
 
+class FederateSLO(models.Model):
+    class Meta:
+        unique_together = ("username", "session_key")
+    username = models.CharField(max_length=30)
+    session_key = models.CharField(max_length=40, blank=True, null=True)
+    ticket = models.CharField(max_length=255)
+
+    @property
+    def provider(self):
+        component = self.username.split("@")
+        return component[-1]
+
+    @classmethod
+    def clean_deleted_sessions(cls):
+        for federate_slo in cls.objects.all():
+            if not SessionStore(session_key=federate_slo.session_key).get('authenticated'):
+                federate_slo.delete()
+
+
 class User(models.Model):
     """A user logged into the CAS"""
     class Meta:

cas_server/utils.py

@@ -184,6 +184,8 @@ def gen_saml_id():
 
 
 def get_tuple(tuple, index, default=None):
+    if tuple is None:
+        return default
     try:
         return tuple[index]
     except IndexError:

cas_server/views.py

@@ -20,7 +20,7 @@ from django.utils.decorators import method_decorator
 from django.utils.translation import ugettext as _
 from django.utils import timezone
 from django.views.decorators.csrf import csrf_exempt
-
+from django.middleware.csrf import CsrfViewMiddleware
 from django.views.generic import View
 
 import logging
@@ -78,6 +78,11 @@ class LogoutMixin(object):
                 username=username,
                 session_key=self.request.session.session_key
             )
+            if settings.CAS_FEDERATE:
+                models.FederateSLO.objects.filter(
+                    username=username,
+                    session_key=self.request.session.session_key
+                ).delete()
             self.request.session.flush()
             user.logout(self.request)
             user.delete()
@@ -181,43 +186,73 @@ class LogoutView(View, LogoutMixin):
 
 
 class FederateAuth(View):
+
+    @method_decorator(csrf_exempt)
+    def dispatch(self, request, *args, **kwargs):
+        return super(FederateAuth, self).dispatch(request, *args, **kwargs)
+
+    def get_cas_client(self, request, provider):
+        if provider in settings.CAS_FEDERATE_PROVIDERS:
+            service_url = utils.get_current_url(request, {"ticket", "provider"})
+            return CASFederateValidateUser(provider, service_url)
+
     def post(self, request, provider=None):
         if not settings.CAS_FEDERATE:
             return redirect("cas_server:login")
-        form = forms.FederateSelect(request.POST)
-        if form.is_valid():
-            params = utils.copy_params(
-                request.POST,
-                ignore={"provider", "csrfmiddlewaretoken", "ticket"}
-            )
-            url = utils.reverse_params(
-                "cas_server:federateAuth",
-                kwargs=dict(provider=form.cleaned_data["provider"]),
-                params=params
-            )
-            response = HttpResponseRedirect(url)
-            if form.cleaned_data["remember"]:
-                max_age = settings.CAS_FEDERATE_REMEMBER_TIMEOUT
-                utils.set_cookie(response, "_remember_provider", request.POST["provider"], max_age)
-            return response
+        # POST with a provider, this is probably an SLO request
+        if provider in settings.CAS_FEDERATE_PROVIDERS:
+            auth = self.get_cas_client(request, provider)
+            try:
+                auth.clean_sessions(request.POST['logoutRequest'])
+            except KeyError:
+                pass
+            return HttpResponse("ok")
+        # else, a User is trying to log in using an identity provider
         else:
-            return redirect("cas_server:login")
+            # Manually checking for csrf to protect the code below
+            reason = CsrfViewMiddleware().process_view(request, None, (), {})
+            if reason is not None:
+                return reason  # Failed the test, stop here.
+            form = forms.FederateSelect(request.POST)
+            if form.is_valid():
+                params = utils.copy_params(
+                    request.POST,
+                    ignore={"provider", "csrfmiddlewaretoken", "ticket"}
+                )
+                url = utils.reverse_params(
+                    "cas_server:federateAuth",
+                    kwargs=dict(provider=form.cleaned_data["provider"]),
+                    params=params
+                )
+                response = HttpResponseRedirect(url)
+                if form.cleaned_data["remember"]:
+                    max_age = settings.CAS_FEDERATE_REMEMBER_TIMEOUT
+                    utils.set_cookie(
+                        response,
+                        "_remember_provider",
+                        request.POST["provider"],
+                        max_age
+                    )
+                return response
+            else:
+                return redirect("cas_server:login")
 
     def get(self, request, provider=None):
         if not settings.CAS_FEDERATE:
             return redirect("cas_server:login")
         if provider not in settings.CAS_FEDERATE_PROVIDERS:
             return redirect("cas_server:login")
-        service_url = utils.get_current_url(request, {"ticket", "provider"})
-        auth = CASFederateValidateUser(provider, service_url)
+        auth = self.get_cas_client(request, provider)
         if 'ticket' not in request.GET:
             return HttpResponseRedirect(auth.get_login_url())
         else:
             ticket = request.GET['ticket']
             if auth.verify_ticket(ticket):
                 params = utils.copy_params(request.GET, ignore={"ticket"})
-                request.session["federate_username"] = "%s@%s" % (auth.username, auth.provider)
+                username = "%s@%s" % (auth.username, auth.provider)
+                request.session["federate_username"] = username
                 request.session["federate_ticket"] = ticket
+                auth.register_slo(username, request.session.session_key, ticket)
                 url = utils.reverse_params("cas_server:login", params)
                 return HttpResponseRedirect(url)
             else: