summary refs log tree commit diff
path: root/tests/handlers/test_oidc.py
blob: a25c89bd5bd3fbc8f9c56086c5b038a052ce8c41 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
# Copyright 2020 Quentin Gliech
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import json
import os
from unittest.mock import ANY, Mock, patch
from urllib.parse import parse_qs, urlparse

import pymacaroons

from synapse.handlers.sso import MappingException
from synapse.server import HomeServer
from synapse.types import UserID
from synapse.util.macaroons import get_value_from_macaroon

from tests.test_utils import FakeResponse, get_awaitable_result, simple_async_mock
from tests.unittest import HomeserverTestCase, override_config

try:
    import authlib  # noqa: F401

    HAS_OIDC = True
except ImportError:
    HAS_OIDC = False


# These are a few constants that are used as config parameters in the tests.
ISSUER = "https://issuer/"
CLIENT_ID = "test-client-id"
CLIENT_SECRET = "test-client-secret"
BASE_URL = "https://synapse/"
CALLBACK_URL = BASE_URL + "_synapse/client/oidc/callback"
SCOPES = ["openid"]

AUTHORIZATION_ENDPOINT = ISSUER + "authorize"
TOKEN_ENDPOINT = ISSUER + "token"
USERINFO_ENDPOINT = ISSUER + "userinfo"
WELL_KNOWN = ISSUER + ".well-known/openid-configuration"
JWKS_URI = ISSUER + ".well-known/jwks.json"

# config for common cases
DEFAULT_CONFIG = {
    "enabled": True,
    "client_id": CLIENT_ID,
    "client_secret": CLIENT_SECRET,
    "issuer": ISSUER,
    "scopes": SCOPES,
    "user_mapping_provider": {"module": __name__ + ".TestMappingProvider"},
}

# extends the default config with explicit OAuth2 endpoints instead of using discovery
EXPLICIT_ENDPOINT_CONFIG = {
    **DEFAULT_CONFIG,
    "discover": False,
    "authorization_endpoint": AUTHORIZATION_ENDPOINT,
    "token_endpoint": TOKEN_ENDPOINT,
    "jwks_uri": JWKS_URI,
}


class TestMappingProvider:
    @staticmethod
    def parse_config(config):
        return

    def __init__(self, config):
        pass

    def get_remote_user_id(self, userinfo):
        return userinfo["sub"]

    async def map_user_attributes(self, userinfo, token):
        return {"localpart": userinfo["username"], "display_name": None}

    # Do not include get_extra_attributes to test backwards compatibility paths.


class TestMappingProviderExtra(TestMappingProvider):
    async def get_extra_attributes(self, userinfo, token):
        return {"phone": userinfo["phone"]}


class TestMappingProviderFailures(TestMappingProvider):
    async def map_user_attributes(self, userinfo, token, failures):
        return {
            "localpart": userinfo["username"] + (str(failures) if failures else ""),
            "display_name": None,
        }


async def get_json(url):
    # Mock get_json calls to handle jwks & oidc discovery endpoints
    if url == WELL_KNOWN:
        # Minimal discovery document, as defined in OpenID.Discovery
        # https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderMetadata
        return {
            "issuer": ISSUER,
            "authorization_endpoint": AUTHORIZATION_ENDPOINT,
            "token_endpoint": TOKEN_ENDPOINT,
            "jwks_uri": JWKS_URI,
            "userinfo_endpoint": USERINFO_ENDPOINT,
            "response_types_supported": ["code"],
            "subject_types_supported": ["public"],
            "id_token_signing_alg_values_supported": ["RS256"],
        }
    elif url == JWKS_URI:
        return {"keys": []}


def _key_file_path() -> str:
    """path to a file containing the private half of a test key"""

    # this key was generated with:
    #   openssl ecparam -name prime256v1 -genkey -noout |
    #       openssl pkcs8 -topk8 -nocrypt -out oidc_test_key.p8
    #
    # we use PKCS8 rather than SEC-1 (which is what openssl ecparam spits out), because
    # that's what Apple use, and we want to be sure that we work with Apple's keys.
    #
    # (For the record: both PKCS8 and SEC-1 specify (different) ways of representing
    # keys using ASN.1. Both are then typically formatted using PEM, which says: use the
    # base64-encoded DER encoding of ASN.1, with headers and footers. But we don't
    # really need to care about any of that.)
    return os.path.join(os.path.dirname(__file__), "oidc_test_key.p8")


def _public_key_file_path() -> str:
    """path to a file containing the public half of a test key"""
    # this was generated with:
    #    openssl ec -in oidc_test_key.p8 -pubout -out oidc_test_key.pub.pem
    #
    # See above about where oidc_test_key.p8 came from
    return os.path.join(os.path.dirname(__file__), "oidc_test_key.pub.pem")


class OidcHandlerTestCase(HomeserverTestCase):
    if not HAS_OIDC:
        skip = "requires OIDC"

    def default_config(self):
        config = super().default_config()
        config["public_baseurl"] = BASE_URL
        return config

    def make_homeserver(self, reactor, clock):
        self.http_client = Mock(spec=["get_json"])
        self.http_client.get_json.side_effect = get_json
        self.http_client.user_agent = "Synapse Test"

        hs = self.setup_test_homeserver(proxied_http_client=self.http_client)

        self.handler = hs.get_oidc_handler()
        self.provider = self.handler._providers["oidc"]
        sso_handler = hs.get_sso_handler()
        # Mock the render error method.
        self.render_error = Mock(return_value=None)
        sso_handler.render_error = self.render_error

        # Reduce the number of attempts when generating MXIDs.
        sso_handler._MAP_USERNAME_RETRIES = 3

        return hs

    def metadata_edit(self, values):
        """Modify the result that will be returned by the well-known query"""

        async def patched_get_json(uri):
            res = await get_json(uri)
            if uri == WELL_KNOWN:
                res.update(values)
            return res

        return patch.object(self.http_client, "get_json", patched_get_json)

    def assertRenderedError(self, error, error_description=None):
        self.render_error.assert_called_once()
        args = self.render_error.call_args[0]
        self.assertEqual(args[1], error)
        if error_description is not None:
            self.assertEqual(args[2], error_description)
        # Reset the render_error mock
        self.render_error.reset_mock()
        return args

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_config(self):
        """Basic config correctly sets up the callback URL and client auth correctly."""
        self.assertEqual(self.provider._callback_url, CALLBACK_URL)
        self.assertEqual(self.provider._client_auth.client_id, CLIENT_ID)
        self.assertEqual(self.provider._client_auth.client_secret, CLIENT_SECRET)

    @override_config({"oidc_config": {**DEFAULT_CONFIG, "discover": True}})
    def test_discovery(self):
        """The handler should discover the endpoints from OIDC discovery document."""
        # This would throw if some metadata were invalid
        metadata = self.get_success(self.provider.load_metadata())
        self.http_client.get_json.assert_called_once_with(WELL_KNOWN)

        self.assertEqual(metadata.issuer, ISSUER)
        self.assertEqual(metadata.authorization_endpoint, AUTHORIZATION_ENDPOINT)
        self.assertEqual(metadata.token_endpoint, TOKEN_ENDPOINT)
        self.assertEqual(metadata.jwks_uri, JWKS_URI)
        # FIXME: it seems like authlib does not have that defined in its metadata models
        # self.assertEqual(metadata.userinfo_endpoint, USERINFO_ENDPOINT)

        # subsequent calls should be cached
        self.http_client.reset_mock()
        self.get_success(self.provider.load_metadata())
        self.http_client.get_json.assert_not_called()

    @override_config({"oidc_config": EXPLICIT_ENDPOINT_CONFIG})
    def test_no_discovery(self):
        """When discovery is disabled, it should not try to load from discovery document."""
        self.get_success(self.provider.load_metadata())
        self.http_client.get_json.assert_not_called()

    @override_config({"oidc_config": EXPLICIT_ENDPOINT_CONFIG})
    def test_load_jwks(self):
        """JWKS loading is done once (then cached) if used."""
        jwks = self.get_success(self.provider.load_jwks())
        self.http_client.get_json.assert_called_once_with(JWKS_URI)
        self.assertEqual(jwks, {"keys": []})

        # subsequent calls should be cached…
        self.http_client.reset_mock()
        self.get_success(self.provider.load_jwks())
        self.http_client.get_json.assert_not_called()

        # …unless forced
        self.http_client.reset_mock()
        self.get_success(self.provider.load_jwks(force=True))
        self.http_client.get_json.assert_called_once_with(JWKS_URI)

        # Throw if the JWKS uri is missing
        original = self.provider.load_metadata

        async def patched_load_metadata():
            m = (await original()).copy()
            m.update({"jwks_uri": None})
            return m

        with patch.object(self.provider, "load_metadata", patched_load_metadata):
            self.get_failure(self.provider.load_jwks(force=True), RuntimeError)

        # Return empty key set if JWKS are not used
        self.provider._scopes = []  # not asking the openid scope
        self.http_client.get_json.reset_mock()
        jwks = self.get_success(self.provider.load_jwks(force=True))
        self.http_client.get_json.assert_not_called()
        self.assertEqual(jwks, {"keys": []})

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_validate_config(self):
        """Provider metadatas are extensively validated."""
        h = self.provider

        def force_load_metadata():
            async def force_load():
                return await h.load_metadata(force=True)

            return get_awaitable_result(force_load())

        # Default test config does not throw
        force_load_metadata()

        with self.metadata_edit({"issuer": None}):
            self.assertRaisesRegex(ValueError, "issuer", force_load_metadata)

        with self.metadata_edit({"issuer": "http://insecure/"}):
            self.assertRaisesRegex(ValueError, "issuer", force_load_metadata)

        with self.metadata_edit({"issuer": "https://invalid/?because=query"}):
            self.assertRaisesRegex(ValueError, "issuer", force_load_metadata)

        with self.metadata_edit({"authorization_endpoint": None}):
            self.assertRaisesRegex(
                ValueError, "authorization_endpoint", force_load_metadata
            )

        with self.metadata_edit({"authorization_endpoint": "http://insecure/auth"}):
            self.assertRaisesRegex(
                ValueError, "authorization_endpoint", force_load_metadata
            )

        with self.metadata_edit({"token_endpoint": None}):
            self.assertRaisesRegex(ValueError, "token_endpoint", force_load_metadata)

        with self.metadata_edit({"token_endpoint": "http://insecure/token"}):
            self.assertRaisesRegex(ValueError, "token_endpoint", force_load_metadata)

        with self.metadata_edit({"jwks_uri": None}):
            self.assertRaisesRegex(ValueError, "jwks_uri", force_load_metadata)

        with self.metadata_edit({"jwks_uri": "http://insecure/jwks.json"}):
            self.assertRaisesRegex(ValueError, "jwks_uri", force_load_metadata)

        with self.metadata_edit({"response_types_supported": ["id_token"]}):
            self.assertRaisesRegex(
                ValueError, "response_types_supported", force_load_metadata
            )

        with self.metadata_edit(
            {"token_endpoint_auth_methods_supported": ["client_secret_basic"]}
        ):
            # should not throw, as client_secret_basic is the default auth method
            force_load_metadata()

        with self.metadata_edit(
            {"token_endpoint_auth_methods_supported": ["client_secret_post"]}
        ):
            self.assertRaisesRegex(
                ValueError,
                "token_endpoint_auth_methods_supported",
                force_load_metadata,
            )

        # Tests for configs that require the userinfo endpoint
        self.assertFalse(h._uses_userinfo)
        self.assertEqual(h._user_profile_method, "auto")
        h._user_profile_method = "userinfo_endpoint"
        self.assertTrue(h._uses_userinfo)

        # Revert the profile method and do not request the "openid" scope: this should
        # mean that we check for a userinfo endpoint
        h._user_profile_method = "auto"
        h._scopes = []
        self.assertTrue(h._uses_userinfo)
        with self.metadata_edit({"userinfo_endpoint": None}):
            self.assertRaisesRegex(ValueError, "userinfo_endpoint", force_load_metadata)

        with self.metadata_edit({"jwks_uri": None}):
            # Shouldn't raise with a valid userinfo, even without jwks
            force_load_metadata()

    @override_config({"oidc_config": {**DEFAULT_CONFIG, "skip_verification": True}})
    def test_skip_verification(self):
        """Provider metadata validation can be disabled by config."""
        with self.metadata_edit({"issuer": "http://insecure"}):
            # This should not throw
            get_awaitable_result(self.provider.load_metadata())

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_redirect_request(self):
        """The redirect request has the right arguments & generates a valid session cookie."""
        req = Mock(spec=["cookies"])
        req.cookies = []

        url = self.get_success(
            self.provider.handle_redirect_request(req, b"http://client/redirect")
        )
        url = urlparse(url)
        auth_endpoint = urlparse(AUTHORIZATION_ENDPOINT)

        self.assertEqual(url.scheme, auth_endpoint.scheme)
        self.assertEqual(url.netloc, auth_endpoint.netloc)
        self.assertEqual(url.path, auth_endpoint.path)

        params = parse_qs(url.query)
        self.assertEqual(params["redirect_uri"], [CALLBACK_URL])
        self.assertEqual(params["response_type"], ["code"])
        self.assertEqual(params["scope"], [" ".join(SCOPES)])
        self.assertEqual(params["client_id"], [CLIENT_ID])
        self.assertEqual(len(params["state"]), 1)
        self.assertEqual(len(params["nonce"]), 1)

        # Check what is in the cookies
        self.assertEqual(len(req.cookies), 2)  # two cookies
        cookie_header = req.cookies[0]

        # The cookie name and path don't really matter, just that it has to be coherent
        # between the callback & redirect handlers.
        parts = [p.strip() for p in cookie_header.split(b";")]
        self.assertIn(b"Path=/_synapse/client/oidc", parts)
        name, cookie = parts[0].split(b"=")
        self.assertEqual(name, b"oidc_session")

        macaroon = pymacaroons.Macaroon.deserialize(cookie)
        state = get_value_from_macaroon(macaroon, "state")
        nonce = get_value_from_macaroon(macaroon, "nonce")
        redirect = get_value_from_macaroon(macaroon, "client_redirect_url")

        self.assertEqual(params["state"], [state])
        self.assertEqual(params["nonce"], [nonce])
        self.assertEqual(redirect, "http://client/redirect")

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_callback_error(self):
        """Errors from the provider returned in the callback are displayed."""
        request = Mock(args={})
        request.args[b"error"] = [b"invalid_client"]
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("invalid_client", "")

        request.args[b"error_description"] = [b"some description"]
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("invalid_client", "some description")

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_callback(self):
        """Code callback works and display errors if something went wrong.

        A lot of scenarios are tested here:
         - when the callback works, with userinfo from ID token
         - when the user mapping fails
         - when ID token verification fails
         - when the callback works, with userinfo fetched from the userinfo endpoint
         - when the userinfo fetching fails
         - when the code exchange fails
        """

        # ensure that we are correctly testing the fallback when "get_extra_attributes"
        # is not implemented.
        mapping_provider = self.provider._user_mapping_provider
        with self.assertRaises(AttributeError):
            _ = mapping_provider.get_extra_attributes

        token = {
            "type": "bearer",
            "id_token": "id_token",
            "access_token": "access_token",
        }
        username = "bar"
        userinfo = {
            "sub": "foo",
            "username": username,
        }
        expected_user_id = "@%s:%s" % (username, self.hs.hostname)
        self.provider._exchange_code = simple_async_mock(return_value=token)
        self.provider._parse_id_token = simple_async_mock(return_value=userinfo)
        self.provider._fetch_userinfo = simple_async_mock(return_value=userinfo)
        auth_handler = self.hs.get_auth_handler()
        auth_handler.complete_sso_login = simple_async_mock()

        code = "code"
        state = "state"
        nonce = "nonce"
        client_redirect_url = "http://client/redirect"
        user_agent = "Browser"
        ip_address = "10.0.0.1"
        session = self._generate_oidc_session_token(state, nonce, client_redirect_url)
        request = _build_callback_request(
            code, state, session, user_agent=user_agent, ip_address=ip_address
        )

        self.get_success(self.handler.handle_oidc_callback(request))

        auth_handler.complete_sso_login.assert_called_once_with(
            expected_user_id, "oidc", request, client_redirect_url, None, new_user=True
        )
        self.provider._exchange_code.assert_called_once_with(code)
        self.provider._parse_id_token.assert_called_once_with(token, nonce=nonce)
        self.provider._fetch_userinfo.assert_not_called()
        self.render_error.assert_not_called()

        # Handle mapping errors
        with patch.object(
            self.provider,
            "_remote_id_from_userinfo",
            new=Mock(side_effect=MappingException()),
        ):
            self.get_success(self.handler.handle_oidc_callback(request))
            self.assertRenderedError("mapping_error")

        # Handle ID token errors
        self.provider._parse_id_token = simple_async_mock(raises=Exception())
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("invalid_token")

        auth_handler.complete_sso_login.reset_mock()
        self.provider._exchange_code.reset_mock()
        self.provider._parse_id_token.reset_mock()
        self.provider._fetch_userinfo.reset_mock()

        # With userinfo fetching
        self.provider._scopes = []  # do not ask the "openid" scope
        self.get_success(self.handler.handle_oidc_callback(request))

        auth_handler.complete_sso_login.assert_called_once_with(
            expected_user_id, "oidc", request, client_redirect_url, None, new_user=False
        )
        self.provider._exchange_code.assert_called_once_with(code)
        self.provider._parse_id_token.assert_not_called()
        self.provider._fetch_userinfo.assert_called_once_with(token)
        self.render_error.assert_not_called()

        # Handle userinfo fetching error
        self.provider._fetch_userinfo = simple_async_mock(raises=Exception())
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("fetch_error")

        # Handle code exchange failure
        from synapse.handlers.oidc import OidcError

        self.provider._exchange_code = simple_async_mock(
            raises=OidcError("invalid_request")
        )
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("invalid_request")

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_callback_session(self):
        """The callback verifies the session presence and validity"""
        request = Mock(spec=["args", "getCookie", "cookies"])

        # Missing cookie
        request.args = {}
        request.getCookie.return_value = None
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("missing_session", "No session cookie found")

        # Missing session parameter
        request.args = {}
        request.getCookie.return_value = "session"
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("invalid_request", "State parameter is missing")

        # Invalid cookie
        request.args = {}
        request.args[b"state"] = [b"state"]
        request.getCookie.return_value = "session"
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("invalid_session")

        # Mismatching session
        session = self._generate_oidc_session_token(
            state="state",
            nonce="nonce",
            client_redirect_url="http://client/redirect",
        )
        request.args = {}
        request.args[b"state"] = [b"mismatching state"]
        request.getCookie.return_value = session
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("mismatching_session")

        # Valid session
        request.args = {}
        request.args[b"state"] = [b"state"]
        request.getCookie.return_value = session
        self.get_success(self.handler.handle_oidc_callback(request))
        self.assertRenderedError("invalid_request")

    @override_config(
        {"oidc_config": {**DEFAULT_CONFIG, "client_auth_method": "client_secret_post"}}
    )
    def test_exchange_code(self):
        """Code exchange behaves correctly and handles various error scenarios."""
        token = {"type": "bearer"}
        token_json = json.dumps(token).encode("utf-8")
        self.http_client.request = simple_async_mock(
            return_value=FakeResponse(code=200, phrase=b"OK", body=token_json)
        )
        code = "code"
        ret = self.get_success(self.provider._exchange_code(code))
        kwargs = self.http_client.request.call_args[1]

        self.assertEqual(ret, token)
        self.assertEqual(kwargs["method"], "POST")
        self.assertEqual(kwargs["uri"], TOKEN_ENDPOINT)

        args = parse_qs(kwargs["data"].decode("utf-8"))
        self.assertEqual(args["grant_type"], ["authorization_code"])
        self.assertEqual(args["code"], [code])
        self.assertEqual(args["client_id"], [CLIENT_ID])
        self.assertEqual(args["client_secret"], [CLIENT_SECRET])
        self.assertEqual(args["redirect_uri"], [CALLBACK_URL])

        # Test error handling
        self.http_client.request = simple_async_mock(
            return_value=FakeResponse(
                code=400,
                phrase=b"Bad Request",
                body=b'{"error": "foo", "error_description": "bar"}',
            )
        )
        from synapse.handlers.oidc import OidcError

        exc = self.get_failure(self.provider._exchange_code(code), OidcError)
        self.assertEqual(exc.value.error, "foo")
        self.assertEqual(exc.value.error_description, "bar")

        # Internal server error with no JSON body
        self.http_client.request = simple_async_mock(
            return_value=FakeResponse(
                code=500,
                phrase=b"Internal Server Error",
                body=b"Not JSON",
            )
        )
        exc = self.get_failure(self.provider._exchange_code(code), OidcError)
        self.assertEqual(exc.value.error, "server_error")

        # Internal server error with JSON body
        self.http_client.request = simple_async_mock(
            return_value=FakeResponse(
                code=500,
                phrase=b"Internal Server Error",
                body=b'{"error": "internal_server_error"}',
            )
        )

        exc = self.get_failure(self.provider._exchange_code(code), OidcError)
        self.assertEqual(exc.value.error, "internal_server_error")

        # 4xx error without "error" field
        self.http_client.request = simple_async_mock(
            return_value=FakeResponse(
                code=400,
                phrase=b"Bad request",
                body=b"{}",
            )
        )
        exc = self.get_failure(self.provider._exchange_code(code), OidcError)
        self.assertEqual(exc.value.error, "server_error")

        # 2xx error with "error" field
        self.http_client.request = simple_async_mock(
            return_value=FakeResponse(
                code=200,
                phrase=b"OK",
                body=b'{"error": "some_error"}',
            )
        )
        exc = self.get_failure(self.provider._exchange_code(code), OidcError)
        self.assertEqual(exc.value.error, "some_error")

    @override_config(
        {
            "oidc_config": {
                "enabled": True,
                "client_id": CLIENT_ID,
                "issuer": ISSUER,
                "client_auth_method": "client_secret_post",
                "client_secret_jwt_key": {
                    "key_file": _key_file_path(),
                    "jwt_header": {"alg": "ES256", "kid": "ABC789"},
                    "jwt_payload": {"iss": "DEFGHI"},
                },
            }
        }
    )
    def test_exchange_code_jwt_key(self):
        """Test that code exchange works with a JWK client secret."""
        from authlib.jose import jwt

        token = {"type": "bearer"}
        self.http_client.request = simple_async_mock(
            return_value=FakeResponse(
                code=200, phrase=b"OK", body=json.dumps(token).encode("utf-8")
            )
        )
        code = "code"

        # advance the clock a bit before we start, so we aren't working with zero
        # timestamps.
        self.reactor.advance(1000)
        start_time = self.reactor.seconds()
        ret = self.get_success(self.provider._exchange_code(code))

        self.assertEqual(ret, token)

        # the request should have hit the token endpoint
        kwargs = self.http_client.request.call_args[1]
        self.assertEqual(kwargs["method"], "POST")
        self.assertEqual(kwargs["uri"], TOKEN_ENDPOINT)

        # the client secret provided to the should be a jwt which can be checked with
        # the public key
        args = parse_qs(kwargs["data"].decode("utf-8"))
        secret = args["client_secret"][0]
        with open(_public_key_file_path()) as f:
            key = f.read()
        claims = jwt.decode(secret, key)
        self.assertEqual(claims.header["kid"], "ABC789")
        self.assertEqual(claims["aud"], ISSUER)
        self.assertEqual(claims["iss"], "DEFGHI")
        self.assertEqual(claims["sub"], CLIENT_ID)
        self.assertEqual(claims["iat"], start_time)
        self.assertGreater(claims["exp"], start_time)

        # check the rest of the POSTed data
        self.assertEqual(args["grant_type"], ["authorization_code"])
        self.assertEqual(args["code"], [code])
        self.assertEqual(args["client_id"], [CLIENT_ID])
        self.assertEqual(args["redirect_uri"], [CALLBACK_URL])

    @override_config(
        {
            "oidc_config": {
                "enabled": True,
                "client_id": CLIENT_ID,
                "issuer": ISSUER,
                "client_auth_method": "none",
            }
        }
    )
    def test_exchange_code_no_auth(self):
        """Test that code exchange works with no client secret."""
        token = {"type": "bearer"}
        self.http_client.request = simple_async_mock(
            return_value=FakeResponse(
                code=200, phrase=b"OK", body=json.dumps(token).encode("utf-8")
            )
        )
        code = "code"
        ret = self.get_success(self.provider._exchange_code(code))

        self.assertEqual(ret, token)

        # the request should have hit the token endpoint
        kwargs = self.http_client.request.call_args[1]
        self.assertEqual(kwargs["method"], "POST")
        self.assertEqual(kwargs["uri"], TOKEN_ENDPOINT)

        # check the POSTed data
        args = parse_qs(kwargs["data"].decode("utf-8"))
        self.assertEqual(args["grant_type"], ["authorization_code"])
        self.assertEqual(args["code"], [code])
        self.assertEqual(args["client_id"], [CLIENT_ID])
        self.assertEqual(args["redirect_uri"], [CALLBACK_URL])

    @override_config(
        {
            "oidc_config": {
                **DEFAULT_CONFIG,
                "user_mapping_provider": {
                    "module": __name__ + ".TestMappingProviderExtra"
                },
            }
        }
    )
    def test_extra_attributes(self):
        """
        Login while using a mapping provider that implements get_extra_attributes.
        """
        token = {
            "type": "bearer",
            "id_token": "id_token",
            "access_token": "access_token",
        }
        userinfo = {
            "sub": "foo",
            "username": "foo",
            "phone": "1234567",
        }
        self.provider._exchange_code = simple_async_mock(return_value=token)
        self.provider._parse_id_token = simple_async_mock(return_value=userinfo)
        auth_handler = self.hs.get_auth_handler()
        auth_handler.complete_sso_login = simple_async_mock()

        state = "state"
        client_redirect_url = "http://client/redirect"
        session = self._generate_oidc_session_token(
            state=state,
            nonce="nonce",
            client_redirect_url=client_redirect_url,
        )
        request = _build_callback_request("code", state, session)

        self.get_success(self.handler.handle_oidc_callback(request))

        auth_handler.complete_sso_login.assert_called_once_with(
            "@foo:test",
            "oidc",
            request,
            client_redirect_url,
            {"phone": "1234567"},
            new_user=True,
        )

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_map_userinfo_to_user(self):
        """Ensure that mapping the userinfo returned from a provider to an MXID works properly."""
        auth_handler = self.hs.get_auth_handler()
        auth_handler.complete_sso_login = simple_async_mock()

        userinfo = {
            "sub": "test_user",
            "username": "test_user",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_called_once_with(
            "@test_user:test", "oidc", ANY, ANY, None, new_user=True
        )
        auth_handler.complete_sso_login.reset_mock()

        # Some providers return an integer ID.
        userinfo = {
            "sub": 1234,
            "username": "test_user_2",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_called_once_with(
            "@test_user_2:test", "oidc", ANY, ANY, None, new_user=True
        )
        auth_handler.complete_sso_login.reset_mock()

        # Test if the mxid is already taken
        store = self.hs.get_datastore()
        user3 = UserID.from_string("@test_user_3:test")
        self.get_success(
            store.register_user(user_id=user3.to_string(), password_hash=None)
        )
        userinfo = {"sub": "test3", "username": "test_user_3"}
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()
        self.assertRenderedError(
            "mapping_error",
            "Mapping provider does not support de-duplicating Matrix IDs",
        )

    @override_config({"oidc_config": {**DEFAULT_CONFIG, "allow_existing_users": True}})
    def test_map_userinfo_to_existing_user(self):
        """Existing users can log in with OpenID Connect when allow_existing_users is True."""
        store = self.hs.get_datastore()
        user = UserID.from_string("@test_user:test")
        self.get_success(
            store.register_user(user_id=user.to_string(), password_hash=None)
        )

        auth_handler = self.hs.get_auth_handler()
        auth_handler.complete_sso_login = simple_async_mock()

        # Map a user via SSO.
        userinfo = {
            "sub": "test",
            "username": "test_user",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_called_once_with(
            user.to_string(), "oidc", ANY, ANY, None, new_user=False
        )
        auth_handler.complete_sso_login.reset_mock()

        # Subsequent calls should map to the same mxid.
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_called_once_with(
            user.to_string(), "oidc", ANY, ANY, None, new_user=False
        )
        auth_handler.complete_sso_login.reset_mock()

        # Note that a second SSO user can be mapped to the same Matrix ID. (This
        # requires a unique sub, but something that maps to the same matrix ID,
        # in this case we'll just use the same username. A more realistic example
        # would be subs which are email addresses, and mapping from the localpart
        # of the email, e.g. bob@foo.com and bob@bar.com -> @bob:test.)
        userinfo = {
            "sub": "test1",
            "username": "test_user",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_called_once_with(
            user.to_string(), "oidc", ANY, ANY, None, new_user=False
        )
        auth_handler.complete_sso_login.reset_mock()

        # Register some non-exact matching cases.
        user2 = UserID.from_string("@TEST_user_2:test")
        self.get_success(
            store.register_user(user_id=user2.to_string(), password_hash=None)
        )
        user2_caps = UserID.from_string("@test_USER_2:test")
        self.get_success(
            store.register_user(user_id=user2_caps.to_string(), password_hash=None)
        )

        # Attempting to login without matching a name exactly is an error.
        userinfo = {
            "sub": "test2",
            "username": "TEST_USER_2",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()
        args = self.assertRenderedError("mapping_error")
        self.assertTrue(
            args[2].startswith(
                "Attempted to login as '@TEST_USER_2:test' but it matches more than one user inexactly:"
            )
        )

        # Logging in when matching a name exactly should work.
        user2 = UserID.from_string("@TEST_USER_2:test")
        self.get_success(
            store.register_user(user_id=user2.to_string(), password_hash=None)
        )

        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_called_once_with(
            "@TEST_USER_2:test", "oidc", ANY, ANY, None, new_user=False
        )

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_map_userinfo_to_invalid_localpart(self):
        """If the mapping provider generates an invalid localpart it should be rejected."""
        self.get_success(
            _make_callback_with_userinfo(self.hs, {"sub": "test2", "username": "föö"})
        )
        self.assertRenderedError("mapping_error", "localpart is invalid: föö")

    @override_config(
        {
            "oidc_config": {
                **DEFAULT_CONFIG,
                "user_mapping_provider": {
                    "module": __name__ + ".TestMappingProviderFailures"
                },
            }
        }
    )
    def test_map_userinfo_to_user_retries(self):
        """The mapping provider can retry generating an MXID if the MXID is already in use."""
        auth_handler = self.hs.get_auth_handler()
        auth_handler.complete_sso_login = simple_async_mock()

        store = self.hs.get_datastore()
        self.get_success(
            store.register_user(user_id="@test_user:test", password_hash=None)
        )
        userinfo = {
            "sub": "test",
            "username": "test_user",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))

        # test_user is already taken, so test_user1 gets registered instead.
        auth_handler.complete_sso_login.assert_called_once_with(
            "@test_user1:test", "oidc", ANY, ANY, None, new_user=True
        )
        auth_handler.complete_sso_login.reset_mock()

        # Register all of the potential mxids for a particular OIDC username.
        self.get_success(
            store.register_user(user_id="@tester:test", password_hash=None)
        )
        for i in range(1, 3):
            self.get_success(
                store.register_user(user_id="@tester%d:test" % i, password_hash=None)
            )

        # Now attempt to map to a username, this will fail since all potential usernames are taken.
        userinfo = {
            "sub": "tester",
            "username": "tester",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()
        self.assertRenderedError(
            "mapping_error", "Unable to generate a Matrix ID from the SSO response"
        )

    @override_config({"oidc_config": DEFAULT_CONFIG})
    def test_empty_localpart(self):
        """Attempts to map onto an empty localpart should be rejected."""
        userinfo = {
            "sub": "tester",
            "username": "",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        self.assertRenderedError("mapping_error", "localpart is invalid: ")

    @override_config(
        {
            "oidc_config": {
                **DEFAULT_CONFIG,
                "user_mapping_provider": {
                    "config": {"localpart_template": "{{ user.username }}"}
                },
            }
        }
    )
    def test_null_localpart(self):
        """Mapping onto a null localpart via an empty OIDC attribute should be rejected"""
        userinfo = {
            "sub": "tester",
            "username": None,
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        self.assertRenderedError("mapping_error", "localpart is invalid: ")

    @override_config(
        {
            "oidc_config": {
                **DEFAULT_CONFIG,
                "attribute_requirements": [{"attribute": "test", "value": "foobar"}],
            }
        }
    )
    def test_attribute_requirements(self):
        """The required attributes must be met from the OIDC userinfo response."""
        auth_handler = self.hs.get_auth_handler()
        auth_handler.complete_sso_login = simple_async_mock()

        # userinfo lacking "test": "foobar" attribute should fail.
        userinfo = {
            "sub": "tester",
            "username": "tester",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()

        # userinfo with "test": "foobar" attribute should succeed.
        userinfo = {
            "sub": "tester",
            "username": "tester",
            "test": "foobar",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))

        # check that the auth handler got called as expected
        auth_handler.complete_sso_login.assert_called_once_with(
            "@tester:test", "oidc", ANY, ANY, None, new_user=True
        )

    @override_config(
        {
            "oidc_config": {
                **DEFAULT_CONFIG,
                "attribute_requirements": [{"attribute": "test", "value": "foobar"}],
            }
        }
    )
    def test_attribute_requirements_contains(self):
        """Test that auth succeeds if userinfo attribute CONTAINS required value"""
        auth_handler = self.hs.get_auth_handler()
        auth_handler.complete_sso_login = simple_async_mock()
        # userinfo with "test": ["foobar", "foo", "bar"] attribute should succeed.
        userinfo = {
            "sub": "tester",
            "username": "tester",
            "test": ["foobar", "foo", "bar"],
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))

        # check that the auth handler got called as expected
        auth_handler.complete_sso_login.assert_called_once_with(
            "@tester:test", "oidc", ANY, ANY, None, new_user=True
        )

    @override_config(
        {
            "oidc_config": {
                **DEFAULT_CONFIG,
                "attribute_requirements": [{"attribute": "test", "value": "foobar"}],
            }
        }
    )
    def test_attribute_requirements_mismatch(self):
        """
        Test that auth fails if attributes exist but don't match,
        or are non-string values.
        """
        auth_handler = self.hs.get_auth_handler()
        auth_handler.complete_sso_login = simple_async_mock()
        # userinfo with "test": "not_foobar" attribute should fail
        userinfo = {
            "sub": "tester",
            "username": "tester",
            "test": "not_foobar",
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()

        # userinfo with "test": ["foo", "bar"] attribute should fail
        userinfo = {
            "sub": "tester",
            "username": "tester",
            "test": ["foo", "bar"],
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()

        # userinfo with "test": False attribute should fail
        # this is largely just to ensure we don't crash here
        userinfo = {
            "sub": "tester",
            "username": "tester",
            "test": False,
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()

        # userinfo with "test": None attribute should fail
        # a value of None breaks the OIDC spec, but it's important to not crash here
        userinfo = {
            "sub": "tester",
            "username": "tester",
            "test": None,
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()

        # userinfo with "test": 1 attribute should fail
        # this is largely just to ensure we don't crash here
        userinfo = {
            "sub": "tester",
            "username": "tester",
            "test": 1,
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()

        # userinfo with "test": 3.14 attribute should fail
        # this is largely just to ensure we don't crash here
        userinfo = {
            "sub": "tester",
            "username": "tester",
            "test": 3.14,
        }
        self.get_success(_make_callback_with_userinfo(self.hs, userinfo))
        auth_handler.complete_sso_login.assert_not_called()

    def _generate_oidc_session_token(
        self,
        state: str,
        nonce: str,
        client_redirect_url: str,
        ui_auth_session_id: str = "",
    ) -> str:
        from synapse.handlers.oidc import OidcSessionData

        return self.handler._token_generator.generate_oidc_session_token(
            state=state,
            session_data=OidcSessionData(
                idp_id="oidc",
                nonce=nonce,
                client_redirect_url=client_redirect_url,
                ui_auth_session_id=ui_auth_session_id,
            ),
        )


async def _make_callback_with_userinfo(
    hs: HomeServer, userinfo: dict, client_redirect_url: str = "http://client/redirect"
) -> None:
    """Mock up an OIDC callback with the given userinfo dict

    We'll pull out the OIDC handler from the homeserver, stub out a couple of methods,
    and poke in the userinfo dict as if it were the response to an OIDC userinfo call.

    Args:
        hs: the HomeServer impl to send the callback to.
        userinfo: the OIDC userinfo dict
        client_redirect_url: the URL to redirect to on success.
    """
    from synapse.handlers.oidc import OidcSessionData

    handler = hs.get_oidc_handler()
    provider = handler._providers["oidc"]
    provider._exchange_code = simple_async_mock(return_value={})
    provider._parse_id_token = simple_async_mock(return_value=userinfo)
    provider._fetch_userinfo = simple_async_mock(return_value=userinfo)

    state = "state"
    session = handler._token_generator.generate_oidc_session_token(
        state=state,
        session_data=OidcSessionData(
            idp_id="oidc",
            nonce="nonce",
            client_redirect_url=client_redirect_url,
            ui_auth_session_id="",
        ),
    )
    request = _build_callback_request("code", state, session)

    await handler.handle_oidc_callback(request)


def _build_callback_request(
    code: str,
    state: str,
    session: str,
    user_agent: str = "Browser",
    ip_address: str = "10.0.0.1",
):
    """Builds a fake SynapseRequest to mock the browser callback

    Returns a Mock object which looks like the SynapseRequest we get from a browser
    after SSO (before we return to the client)

    Args:
        code: the authorization code which would have been returned by the OIDC
           provider
        state: the "state" param which would have been passed around in the
           query param. Should be the same as was embedded in the session in
           _build_oidc_session.
        session: the "session" which would have been passed around in the cookie.
        user_agent: the user-agent to present
        ip_address: the IP address to pretend the request came from
    """
    request = Mock(
        spec=[
            "args",
            "getCookie",
            "cookies",
            "requestHeaders",
            "getClientIP",
            "getHeader",
        ]
    )

    request.cookies = []
    request.getCookie.return_value = session
    request.args = {}
    request.args[b"code"] = [code.encode("utf-8")]
    request.args[b"state"] = [state.encode("utf-8")]
    request.getClientIP.return_value = ip_address
    return request