Add some tests for the IDP picker flow

3 files changed, 193 insertions, 5 deletions

diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index ebc346105b..be938df962 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -319,9 +319,9 @@ class SsoRedirectServlet(RestServlet):
         # register themselves with the main SSOHandler.
         if hs.config.cas_enabled:
             hs.get_cas_handler()
-        elif hs.config.saml2_enabled:
+        if hs.config.saml2_enabled:
             hs.get_saml_handler()
-        elif hs.config.oidc_enabled:
+        if hs.config.oidc_enabled:
             hs.get_oidc_handler()
         self._sso_handler = hs.get_sso_handler()
 
diff --git a/tests/rest/client/v1/test_login.py b/tests/rest/client/v1/test_login.py
index b5a2ac23d4..1d1dc9f8a2 100644
--- a/tests/rest/client/v1/test_login.py
+++ b/tests/rest/client/v1/test_login.py
@@ -15,17 +15,26 @@
 
 import time
 import urllib.parse
-from typing import Any, Dict, Union
+from html.parser import HTMLParser
+from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
 
 from mock import Mock
 
+import pymacaroons
+
+from twisted.web.resource import Resource
+
 import synapse.rest.admin
 from synapse.appservice import ApplicationService
 from synapse.rest.client.v1 import login, logout
 from synapse.rest.client.v2_alpha import devices, register
 from synapse.rest.client.v2_alpha.account import WhoamiRestServlet
+from synapse.rest.synapse.client.pick_idp import PickIdpResource
 
 from tests import unittest
+from tests.handlers.test_oidc import HAS_OIDC
+from tests.handlers.test_saml import has_saml2
+from tests.rest.client.v1.utils import TEST_OIDC_AUTH_ENDPOINT, TEST_OIDC_CONFIG
 from tests.unittest import override_config, skip_unless
 
 try:
@@ -350,6 +359,184 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
 
+@skip_unless(has_saml2 and HAS_OIDC, "Requires SAML2 and OIDC")
+class MultiSSOTestCase(unittest.HomeserverTestCase):
+    """Tests for homeservers with multiple SSO providers enabled"""
+
+    servlets = [
+        login.register_servlets,
+    ]
+
+    def default_config(self) -> Dict[str, Any]:
+        config = super().default_config()
+
+        config["public_baseurl"] = BASE_URL
+
+        config["cas_config"] = {
+            "enabled": True,
+            "server_url": CAS_SERVER,
+            "service_url": "https://matrix.goodserver.com:8448",
+        }
+
+        config["saml2_config"] = {
+            "sp_config": {
+                "metadata": {"inline": [TEST_SAML_METADATA]},
+                # use the XMLSecurity backend to avoid relying on xmlsec1
+                "crypto_backend": "XMLSecurity",
+            },
+        }
+
+        config["oidc_config"] = TEST_OIDC_CONFIG
+
+        return config
+
+    def create_resource_dict(self) -> Dict[str, Resource]:
+        d = super().create_resource_dict()
+        d["/_synapse/client/pick_idp"] = PickIdpResource(self.hs)
+        return d
+
+    def test_multi_sso_redirect(self):
+        """/login/sso/redirect should redirect to an identity picker"""
+        client_redirect_url = "https://x?<abc>"
+
+        # first hit the redirect url, which should redirect to our idp picker
+        channel = self.make_request(
+            "GET",
+            "/_matrix/client/r0/login/sso/redirect?redirectUrl=" + client_redirect_url,
+        )
+        self.assertEqual(channel.code, 302, channel.result)
+        uri = channel.headers.getRawHeaders("Location")[0]
+
+        # hitting that picker should give us some HTML
+        channel = self.make_request("GET", uri)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        # parse the form to check it has fields assumed elsewhere in this class
+        class FormPageParser(HTMLParser):
+            def __init__(self):
+                super().__init__()
+
+                # the values of the hidden inputs: map from name to value
+                self.hiddens = {}  # type: Dict[str, Optional[str]]
+
+                # the values of the radio buttons
+                self.radios = []  # type: List[Optional[str]]
+
+            def handle_starttag(
+                self, tag: str, attrs: Iterable[Tuple[str, Optional[str]]]
+            ) -> None:
+                attr_dict = dict(attrs)
+                if tag == "input":
+                    if attr_dict["type"] == "radio" and attr_dict["name"] == "idp":
+                        self.radios.append(attr_dict["value"])
+                    elif attr_dict["type"] == "hidden":
+                        input_name = attr_dict["name"]
+                        assert input_name
+                        self.hiddens[input_name] = attr_dict["value"]
+
+            def error(_, message):
+                self.fail(message)
+
+        p = FormPageParser()
+        p.feed(channel.result["body"].decode("utf-8"))
+        p.close()
+
+        self.assertCountEqual(p.radios, ["cas", "oidc", "saml"])
+
+        self.assertEqual(p.hiddens["redirectUrl"], client_redirect_url)
+
+    def test_multi_sso_redirect_to_cas(self):
+        """If CAS is chosen, should redirect to the CAS server"""
+        client_redirect_url = "https://x?<abc>"
+
+        channel = self.make_request(
+            "GET",
+            "/_synapse/client/pick_idp?redirectUrl=" + client_redirect_url + "&idp=cas",
+            shorthand=False,
+        )
+        self.assertEqual(channel.code, 302, channel.result)
+        cas_uri = channel.headers.getRawHeaders("Location")[0]
+        cas_uri_path, cas_uri_query = cas_uri.split("?", 1)
+
+        # it should redirect us to the login page of the cas server
+        self.assertEqual(cas_uri_path, CAS_SERVER + "/login")
+
+        # check that the redirectUrl is correctly encoded in the service param - ie, the
+        # place that CAS will redirect to
+        cas_uri_params = urllib.parse.parse_qs(cas_uri_query)
+        service_uri = cas_uri_params["service"][0]
+        _, service_uri_query = service_uri.split("?", 1)
+        service_uri_params = urllib.parse.parse_qs(service_uri_query)
+        self.assertEqual(service_uri_params["redirectUrl"][0], client_redirect_url)
+
+    def test_multi_sso_redirect_to_saml(self):
+        """If SAML is chosen, should redirect to the SAML server"""
+        client_redirect_url = "https://x?<abc>"
+
+        channel = self.make_request(
+            "GET",
+            "/_synapse/client/pick_idp?redirectUrl="
+            + client_redirect_url
+            + "&idp=saml",
+        )
+        self.assertEqual(channel.code, 302, channel.result)
+        saml_uri = channel.headers.getRawHeaders("Location")[0]
+        saml_uri_path, saml_uri_query = saml_uri.split("?", 1)
+
+        # it should redirect us to the login page of the SAML server
+        self.assertEqual(saml_uri_path, SAML_SERVER)
+
+        # the RelayState is used to carry the client redirect url
+        saml_uri_params = urllib.parse.parse_qs(saml_uri_query)
+        relay_state_param = saml_uri_params["RelayState"][0]
+        self.assertEqual(relay_state_param, client_redirect_url)
+
+    def test_multi_sso_redirect_to_oidc(self):
+        """If OIDC is chosen, should redirect to the OIDC auth endpoint"""
+        client_redirect_url = "https://x?<abc>"
+
+        channel = self.make_request(
+            "GET",
+            "/_synapse/client/pick_idp?redirectUrl="
+            + client_redirect_url
+            + "&idp=oidc",
+        )
+        self.assertEqual(channel.code, 302, channel.result)
+        oidc_uri = channel.headers.getRawHeaders("Location")[0]
+        oidc_uri_path, oidc_uri_query = oidc_uri.split("?", 1)
+
+        # it should redirect us to the auth page of the OIDC server
+        self.assertEqual(oidc_uri_path, TEST_OIDC_AUTH_ENDPOINT)
+
+        # ... and should have set a cookie including the redirect url
+        cookies = dict(
+            h.split(";")[0].split("=", maxsplit=1)
+            for h in channel.headers.getRawHeaders("Set-Cookie")
+        )
+
+        oidc_session_cookie = cookies["oidc_session"]
+        macaroon = pymacaroons.Macaroon.deserialize(oidc_session_cookie)
+        self.assertEqual(
+            self._get_value_from_macaroon(macaroon, "client_redirect_url"),
+            client_redirect_url,
+        )
+
+    def test_multi_sso_redirect_to_unknown(self):
+        """An unknown IdP should cause a 400"""
+        channel = self.make_request(
+            "GET", "/_synapse/client/pick_idp?redirectUrl=http://x&idp=xyz",
+        )
+        self.assertEqual(channel.code, 400, channel.result)
+
+    @staticmethod
+    def _get_value_from_macaroon(macaroon: pymacaroons.Macaroon, key: str) -> str:
+        prefix = key + " = "
+        for caveat in macaroon.caveats:
+            if caveat.caveat_id.startswith(prefix):
+                return caveat.caveat_id[len(prefix) :]
+        raise ValueError("No %s caveat in macaroon" % (key,))
+
+
 class CASTestCase(unittest.HomeserverTestCase):
 
     servlets = [
@@ -363,7 +550,7 @@ class CASTestCase(unittest.HomeserverTestCase):
         config = self.default_config()
         config["cas_config"] = {
             "enabled": True,
-            "server_url": "https://fake.test",
+            "server_url": CAS_SERVER,
             "service_url": "https://matrix.goodserver.com:8448",
         }
 
diff --git a/tests/rest/client/v1/utils.py b/tests/rest/client/v1/utils.py
index dbc27893b5..81b7f84360 100644
--- a/tests/rest/client/v1/utils.py
+++ b/tests/rest/client/v1/utils.py
@@ -444,6 +444,7 @@ class RestHelper:
 
 
 # an 'oidc_config' suitable for login_via_oidc.
+TEST_OIDC_AUTH_ENDPOINT = "https://issuer.test/auth"
 TEST_OIDC_CONFIG = {
     "enabled": True,
     "discover": False,
@@ -451,7 +452,7 @@ TEST_OIDC_CONFIG = {
     "client_id": "test-client-id",
     "client_secret": "test-client-secret",
     "scopes": ["profile"],
-    "authorization_endpoint": "https://z",
+    "authorization_endpoint": TEST_OIDC_AUTH_ENDPOINT,
     "token_endpoint": "https://issuer.test/token",
     "userinfo_endpoint": "https://issuer.test/userinfo",
     "user_mapping_provider": {"config": {"localpart_template": "{{ user.sub }}"}},