From 8e6b69546effcc199d37683668a99bad1e05bb6c Mon Sep 17 00:00:00 2001
From: Josue Kouka <jkouka@entrouvert.com>
Date: Wed, 31 Jan 2018 17:11:16 +0100
Subject: [PATCH 3/3] add rp remote idp authentication (#16842)

---
 fargo/oauth2/authentication.py | 46 ++++++++++++++++++++++++++++++++++++-
 tests/test_oauth2.py           | 52 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/fargo/oauth2/authentication.py b/fargo/oauth2/authentication.py
index c3822b2..c326a08 100644
--- a/fargo/oauth2/authentication.py
+++ b/fargo/oauth2/authentication.py
@@ -14,6 +14,13 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import urlparse
+import logging
+
+import requests
+
+from django.conf import settings
+
 from django.utils.translation import ugettext_lazy as _
 
 from rest_framework.authentication import BasicAuthentication
@@ -51,12 +58,49 @@ class OAuth2User(object):
 
 class FargoOAUTH2Authentication(BasicAuthentication):
 
+    def authenticate_through_idp(self, client_id, client_secret):
+        '''Check client_id and client_secret with configured IdP, and verify it is an OIDC
+           client.
+        '''
+        logger = logging.getLogger(__name__)
+
+        authentic_idp = getattr(settings, 'FARGO_IDP_URL', None)
+        if not authentic_idp:
+            logger.warning(u'idp check-password not configured')
+            return False, ''
+
+        url = urlparse.urljoin(authentic_idp, 'api/check-password/')
+        try:
+            response = requests.post(url, json={
+                'username': client_id,
+                'password': client_secret}, auth=(client_id, client_secret), verify=False)
+            response.raise_for_status()
+        except requests.RequestException as e:
+            logger.warning(u'idp check-password API failed: %s', e)
+            return False, 'idp is down'
+        try:
+            response = response.json()
+        except ValueError as e:
+            logger.warning(u'idp check-password API failed: %s, %r', e, response.content)
+            return False, 'idp is down'
+
+        if response.get('result') == 0:
+            logger.warning(u'idp check-password API failed')
+            return False, response.get('errors', [''])[0]
+
+        return True, None
+
     def authenticate_credentials(self, client_id, client_secret):
         try:
             client = OAuth2Client.objects.get(
                 client_id=client_id, client_secret=client_secret)
         except OAuth2Client.DoesNotExist:
-            raise AuthenticationFailed(_('Invalid client_id/client_secret.'))
+            success, error = self.authenticate_through_idp(client_id, client_secret)
+            if not success:
+                raise AuthenticationFailed(error or _('Invalid client_id/client_secret.'))
+            client = OAuth2Client.objects.get(client_id=client_id)
+            client.client_secret = client_secret
+            client.save()
 
         user = OAuth2User(client)
         user.authenticated = True
diff --git a/tests/test_oauth2.py b/tests/test_oauth2.py
index cab651a..511d6cf 100644
--- a/tests/test_oauth2.py
+++ b/tests/test_oauth2.py
@@ -1,3 +1,5 @@
+import json
+import mock
 import pytest
 from urllib import quote
 import urlparse
@@ -14,6 +16,12 @@ from test_manager import login
 pytestmark = pytest.mark.django_db
 
 
+class FakedResponse(mock.Mock):
+
+    def json(self):
+        return json.loads(self.content)
+
+
 @pytest.fixture
 def oauth2_client():
     return OAuth2Client.objects.create(
@@ -160,3 +168,47 @@ def test_confirm_put_document_file_exception(app, john_doe, user_doc):
     url += '?%s' % urlencode({'redirect_uri': 'https://example.com'})
     resp = app.get(url)
     assert 'This document is already in your portfolio' in resp.content
+
+
+@mock.patch('fargo.oauth2.authentication.requests.post')
+def test_idp_authentication(mocked_post, settings, app, oauth2_client, john_doe, user_doc):
+    login(app, user=john_doe)
+    url = reverse('oauth2-authorize')
+    params = {
+        'client_id': oauth2_client.client_id,
+        'client_secret': 'fake',
+        'response_type': 'code',
+        'state': 'achipeachope',
+        'redirect': 'https://example.com/'
+    }
+    params['redirect_uri'] = 'https://example.com'
+    resp = app.get(url, params=params)
+    resp.forms[0]['document'].select('1')
+    resp = resp.forms[0].submit()
+    auth = OAuth2Authorize.objects.filter(user_document__user=john_doe)[0]
+    params.pop('response_type')
+    params.pop('state')
+    params['grant_type'] = 'authorization_code'
+    params['code'] = auth.code
+
+    url = reverse('oauth2-get-token')
+    # when remote remote idp not set
+    app.authorization = ('Basic', ('client-id', 'fake'))
+    resp = app.post(url, params=params, status=401)
+    resp.json['detail'] == 'Invalid client_id/client_secret.'
+    # when remote idp fails to authenticate rp
+    settings.FARGO_IDP_URL = 'https://idp.example.org'
+    response = {
+        "result": 0, "errors": ["Invalid username/password."]
+    }
+    mocked_post.return_value = FakedResponse(content=json.dumps(response))
+    resp = app.post(url, params=params, status=401)
+    resp.json['detail'] == 'Invalid client_id/client_secret.'
+    # when remote idp authenticates rp
+    response = {"result": 1, "errors": []}
+    mocked_post.return_value = FakedResponse(content=json.dumps(response))
+    resp = app.post(url, params=params, status=200)
+    assert resp.json['access_token'] == auth.access_token
+    url = reverse('oauth2-get-document')
+    app.authorization = ('Bearer', str(auth.access_token))
+    resp = app.get(url, status=200)
-- 
2.11.0