427 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			427 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Python
		
	
	
# Copyright 2020 Quentin Gliech
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# Copyright 2020-2021 The Matrix.org Foundation C.I.C.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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#     http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from collections import Counter
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from typing import Any, Collection, Iterable, List, Mapping, Optional, Tuple, Type
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import attr
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from synapse.config._util import validate_config
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from synapse.config.sso import SsoAttributeRequirement
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from synapse.types import JsonDict
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from synapse.util.module_loader import load_module
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from synapse.util.stringutils import parse_and_validate_mxc_uri
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from ..util.check_dependencies import check_requirements
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from ._base import Config, ConfigError, read_file
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DEFAULT_USER_MAPPING_PROVIDER = "synapse.handlers.oidc.JinjaOidcMappingProvider"
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# The module that JinjaOidcMappingProvider is in was renamed, we want to
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# transparently handle both the same.
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LEGACY_USER_MAPPING_PROVIDER = "synapse.handlers.oidc_handler.JinjaOidcMappingProvider"
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class OIDCConfig(Config):
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    section = "oidc"
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    def read_config(self, config: JsonDict, **kwargs: Any) -> None:
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        self.oidc_providers = tuple(_parse_oidc_provider_configs(config))
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        if not self.oidc_providers:
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            return
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        check_requirements("oidc")
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        # check we don't have any duplicate idp_ids now. (The SSO handler will also
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        # check for duplicates when the REST listeners get registered, but that happens
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        # after synapse has forked so doesn't give nice errors.)
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        c = Counter([i.idp_id for i in self.oidc_providers])
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        for idp_id, count in c.items():
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            if count > 1:
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                raise ConfigError(
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                    "Multiple OIDC providers have the idp_id %r." % idp_id
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                )
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        public_baseurl = self.root.server.public_baseurl
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        self.oidc_callback_url = public_baseurl + "_synapse/client/oidc/callback"
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    @property
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    def oidc_enabled(self) -> bool:
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        # OIDC is enabled if we have a provider
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        return bool(self.oidc_providers)
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# jsonschema definition of the configuration settings for an oidc identity provider
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OIDC_PROVIDER_CONFIG_SCHEMA = {
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    "type": "object",
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    "required": ["issuer", "client_id"],
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    "properties": {
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        "idp_id": {
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            "type": "string",
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            "minLength": 1,
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            # MSC2858 allows a maxlen of 255, but we prefix with "oidc-"
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            "maxLength": 250,
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            "pattern": "^[A-Za-z0-9._~-]+$",
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        },
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        "idp_name": {"type": "string"},
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        "idp_icon": {"type": "string"},
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        "idp_brand": {
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            "type": "string",
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            "minLength": 1,
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            "maxLength": 255,
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            "pattern": "^[a-z][a-z0-9_.-]*$",
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        },
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        "discover": {"type": "boolean"},
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        "issuer": {"type": "string"},
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        "client_id": {"type": "string"},
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        "client_secret": {"type": "string"},
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        "client_secret_jwt_key": {
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            "type": "object",
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            "required": ["jwt_header"],
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            "oneOf": [
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                {"required": ["key"]},
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                {"required": ["key_file"]},
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            ],
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            "properties": {
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                "key": {"type": "string"},
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                "key_file": {"type": "string"},
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                "jwt_header": {
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                    "type": "object",
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                    "required": ["alg"],
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                    "properties": {
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                        "alg": {"type": "string"},
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                    },
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                    "additionalProperties": {"type": "string"},
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                },
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                "jwt_payload": {
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                    "type": "object",
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                    "additionalProperties": {"type": "string"},
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                },
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            },
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        },
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        "client_auth_method": {
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            "type": "string",
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            # the following list is the same as the keys of
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            # authlib.oauth2.auth.ClientAuth.DEFAULT_AUTH_METHODS. We inline it
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            # to avoid importing authlib here.
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            "enum": ["client_secret_basic", "client_secret_post", "none"],
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        },
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        "pkce_method": {"type": "string", "enum": ["auto", "always", "never"]},
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        "scopes": {"type": "array", "items": {"type": "string"}},
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        "authorization_endpoint": {"type": "string"},
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        "token_endpoint": {"type": "string"},
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        "userinfo_endpoint": {"type": "string"},
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        "jwks_uri": {"type": "string"},
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        "skip_verification": {"type": "boolean"},
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        "backchannel_logout_enabled": {"type": "boolean"},
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        "backchannel_logout_ignore_sub": {"type": "boolean"},
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        "user_profile_method": {
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            "type": "string",
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            "enum": ["auto", "userinfo_endpoint"],
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        },
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        "allow_existing_users": {"type": "boolean"},
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        "user_mapping_provider": {"type": ["object", "null"]},
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        "attribute_requirements": {
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            "type": "array",
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            "items": SsoAttributeRequirement.JSON_SCHEMA,
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        },
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        "enable_registration": {"type": "boolean"},
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    },
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}
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# the same as OIDC_PROVIDER_CONFIG_SCHEMA, but with compulsory idp_id and idp_name
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OIDC_PROVIDER_CONFIG_WITH_ID_SCHEMA = {
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    "allOf": [OIDC_PROVIDER_CONFIG_SCHEMA, {"required": ["idp_id", "idp_name"]}]
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}
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# the `oidc_providers` list can either be None (as it is in the default config), or
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# a list of provider configs, each of which requires an explicit ID and name.
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OIDC_PROVIDER_LIST_SCHEMA = {
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    "oneOf": [
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        {"type": "null"},
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        {"type": "array", "items": OIDC_PROVIDER_CONFIG_WITH_ID_SCHEMA},
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    ]
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}
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# the `oidc_config` setting can either be None (which it used to be in the default
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# config), or an object. If an object, it is ignored unless it has an "enabled: True"
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# property.
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#
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# It's *possible* to represent this with jsonschema, but the resultant errors aren't
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# particularly clear, so we just check for either an object or a null here, and do
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# additional checks in the code.
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OIDC_CONFIG_SCHEMA = {"oneOf": [{"type": "null"}, {"type": "object"}]}
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# the top-level schema can contain an "oidc_config" and/or an "oidc_providers".
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MAIN_CONFIG_SCHEMA = {
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    "type": "object",
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    "properties": {
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        "oidc_config": OIDC_CONFIG_SCHEMA,
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        "oidc_providers": OIDC_PROVIDER_LIST_SCHEMA,
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    },
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}
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def _parse_oidc_provider_configs(config: JsonDict) -> Iterable["OidcProviderConfig"]:
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    """extract and parse the OIDC provider configs from the config dict
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    The configuration may contain either a single `oidc_config` object with an
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    `enabled: True` property, or a list of provider configurations under
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    `oidc_providers`, *or both*.
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    Returns a generator which yields the OidcProviderConfig objects
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    """
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    validate_config(MAIN_CONFIG_SCHEMA, config, ())
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    for i, p in enumerate(config.get("oidc_providers") or []):
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        yield _parse_oidc_config_dict(p, ("oidc_providers", "<item %i>" % (i,)))
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    # for backwards-compatibility, it is also possible to provide a single "oidc_config"
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    # object with an "enabled: True" property.
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    oidc_config = config.get("oidc_config")
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    if oidc_config and oidc_config.get("enabled", False):
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        # MAIN_CONFIG_SCHEMA checks that `oidc_config` is an object, but not that
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        # it matches OIDC_PROVIDER_CONFIG_SCHEMA (see the comments on OIDC_CONFIG_SCHEMA
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        # above), so now we need to validate it.
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        validate_config(OIDC_PROVIDER_CONFIG_SCHEMA, oidc_config, ("oidc_config",))
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        yield _parse_oidc_config_dict(oidc_config, ("oidc_config",))
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def _parse_oidc_config_dict(
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    oidc_config: JsonDict, config_path: Tuple[str, ...]
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) -> "OidcProviderConfig":
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    """Take the configuration dict and parse it into an OidcProviderConfig
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    Raises:
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        ConfigError if the configuration is malformed.
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    """
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    ump_config = oidc_config.get("user_mapping_provider", {})
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    ump_config.setdefault("module", DEFAULT_USER_MAPPING_PROVIDER)
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    if ump_config.get("module") == LEGACY_USER_MAPPING_PROVIDER:
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        ump_config["module"] = DEFAULT_USER_MAPPING_PROVIDER
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    ump_config.setdefault("config", {})
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    (
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        user_mapping_provider_class,
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        user_mapping_provider_config,
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    ) = load_module(ump_config, config_path + ("user_mapping_provider",))
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    # Ensure loaded user mapping module has defined all necessary methods
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    required_methods = [
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        "get_remote_user_id",
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        "map_user_attributes",
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    ]
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    missing_methods = [
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        method
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        for method in required_methods
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        if not hasattr(user_mapping_provider_class, method)
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    ]
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    if missing_methods:
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        raise ConfigError(
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            "Class %s is missing required "
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            "methods: %s"
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            % (
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                user_mapping_provider_class,
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                ", ".join(missing_methods),
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            ),
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            config_path + ("user_mapping_provider", "module"),
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        )
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    idp_id = oidc_config.get("idp_id", "oidc")
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    # prefix the given IDP with a prefix specific to the SSO mechanism, to avoid
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    # clashes with other mechs (such as SAML, CAS).
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    #
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    # We allow "oidc" as an exception so that people migrating from old-style
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    # "oidc_config" format (which has long used "oidc" as its idp_id) can migrate to
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    # a new-style "oidc_providers" entry without changing the idp_id for their provider
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    # (and thereby invalidating their user_external_ids data).
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    if idp_id != "oidc":
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        idp_id = "oidc-" + idp_id
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    # MSC2858 also specifies that the idp_icon must be a valid MXC uri
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    idp_icon = oidc_config.get("idp_icon")
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    if idp_icon is not None:
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        try:
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            parse_and_validate_mxc_uri(idp_icon)
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        except ValueError as e:
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            raise ConfigError(
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                "idp_icon must be a valid MXC URI", config_path + ("idp_icon",)
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            ) from e
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    client_secret_jwt_key_config = oidc_config.get("client_secret_jwt_key")
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    client_secret_jwt_key: Optional[OidcProviderClientSecretJwtKey] = None
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    if client_secret_jwt_key_config is not None:
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        keyfile = client_secret_jwt_key_config.get("key_file")
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        if keyfile:
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            key = read_file(keyfile, config_path + ("client_secret_jwt_key",))
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        else:
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            key = client_secret_jwt_key_config["key"]
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        client_secret_jwt_key = OidcProviderClientSecretJwtKey(
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            key=key,
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            jwt_header=client_secret_jwt_key_config["jwt_header"],
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            jwt_payload=client_secret_jwt_key_config.get("jwt_payload", {}),
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        )
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    # parse attribute_requirements from config (list of dicts) into a list of SsoAttributeRequirement
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    attribute_requirements = [
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        SsoAttributeRequirement(**x)
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        for x in oidc_config.get("attribute_requirements", [])
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    ]
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    # Read from either `client_secret_path` or `client_secret`. If both exist, error.
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    client_secret = oidc_config.get("client_secret")
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    client_secret_path = oidc_config.get("client_secret_path")
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    if client_secret_path is not None:
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        if client_secret is None:
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            client_secret = read_file(
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                client_secret_path, config_path + ("client_secret_path",)
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            ).rstrip("\n")
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        else:
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            raise ConfigError(
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                "Cannot specify both client_secret and client_secret_path",
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                config_path + ("client_secret",),
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            )
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    return OidcProviderConfig(
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        idp_id=idp_id,
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        idp_name=oidc_config.get("idp_name", "OIDC"),
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        idp_icon=idp_icon,
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        idp_brand=oidc_config.get("idp_brand"),
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        discover=oidc_config.get("discover", True),
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        issuer=oidc_config["issuer"],
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        client_id=oidc_config["client_id"],
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        client_secret=client_secret,
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        client_secret_jwt_key=client_secret_jwt_key,
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        client_auth_method=oidc_config.get("client_auth_method", "client_secret_basic"),
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        pkce_method=oidc_config.get("pkce_method", "auto"),
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        scopes=oidc_config.get("scopes", ["openid"]),
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        authorization_endpoint=oidc_config.get("authorization_endpoint"),
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        token_endpoint=oidc_config.get("token_endpoint"),
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        userinfo_endpoint=oidc_config.get("userinfo_endpoint"),
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        jwks_uri=oidc_config.get("jwks_uri"),
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        backchannel_logout_enabled=oidc_config.get("backchannel_logout_enabled", False),
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        backchannel_logout_ignore_sub=oidc_config.get(
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            "backchannel_logout_ignore_sub", False
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        ),
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        skip_verification=oidc_config.get("skip_verification", False),
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        user_profile_method=oidc_config.get("user_profile_method", "auto"),
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        allow_existing_users=oidc_config.get("allow_existing_users", False),
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        user_mapping_provider_class=user_mapping_provider_class,
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        user_mapping_provider_config=user_mapping_provider_config,
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        attribute_requirements=attribute_requirements,
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        enable_registration=oidc_config.get("enable_registration", True),
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    )
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@attr.s(slots=True, frozen=True, auto_attribs=True)
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class OidcProviderClientSecretJwtKey:
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    # a pem-encoded signing key
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    key: str
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    # properties to include in the JWT header
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    jwt_header: Mapping[str, str]
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    # properties to include in the JWT payload.
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    jwt_payload: Mapping[str, str]
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@attr.s(slots=True, frozen=True, auto_attribs=True)
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class OidcProviderConfig:
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    # a unique identifier for this identity provider. Used in the 'user_external_ids'
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    # table, as well as the query/path parameter used in the login protocol.
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    idp_id: str
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    # user-facing name for this identity provider.
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    idp_name: str
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    # Optional MXC URI for icon for this IdP.
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    idp_icon: Optional[str]
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    # Optional brand identifier for this IdP.
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    idp_brand: Optional[str]
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    # whether the OIDC discovery mechanism is used to discover endpoints
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    discover: bool
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    # the OIDC issuer. Used to validate tokens and (if discovery is enabled) to
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    # discover the provider's endpoints.
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    issuer: str
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    # oauth2 client id to use
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    client_id: str
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    # oauth2 client secret to use. if `None`, use client_secret_jwt_key to generate
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    # a secret.
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    client_secret: Optional[str]
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    # key to use to construct a JWT to use as a client secret. May be `None` if
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    # `client_secret` is set.
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    client_secret_jwt_key: Optional[OidcProviderClientSecretJwtKey]
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    # auth method to use when exchanging the token.
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    # Valid values are 'client_secret_basic', 'client_secret_post' and
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    # 'none'.
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    client_auth_method: str
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    # Whether to enable PKCE when exchanging the authorization & token.
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    # Valid values are 'auto', 'always', and 'never'.
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    pkce_method: str
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    # list of scopes to request
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    scopes: Collection[str]
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    # the oauth2 authorization endpoint. Required if discovery is disabled.
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    authorization_endpoint: Optional[str]
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    # the oauth2 token endpoint. Required if discovery is disabled.
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    token_endpoint: Optional[str]
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    # the OIDC userinfo endpoint. Required if discovery is disabled and the
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    # "openid" scope is not requested.
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    userinfo_endpoint: Optional[str]
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    # URI where to fetch the JWKS. Required if discovery is disabled and the
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    # "openid" scope is used.
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    jwks_uri: Optional[str]
 | 
						|
 | 
						|
    # Whether Synapse should react to backchannel logouts
 | 
						|
    backchannel_logout_enabled: bool
 | 
						|
 | 
						|
    # Whether Synapse should ignore the `sub` claim in backchannel logouts or not.
 | 
						|
    backchannel_logout_ignore_sub: bool
 | 
						|
 | 
						|
    # Whether to skip metadata verification
 | 
						|
    skip_verification: bool
 | 
						|
 | 
						|
    # Whether to fetch the user profile from the userinfo endpoint. Valid
 | 
						|
    # values are: "auto" or "userinfo_endpoint".
 | 
						|
    user_profile_method: str
 | 
						|
 | 
						|
    # whether to allow a user logging in via OIDC to match a pre-existing account
 | 
						|
    # instead of failing
 | 
						|
    allow_existing_users: bool
 | 
						|
 | 
						|
    # the class of the user mapping provider
 | 
						|
    user_mapping_provider_class: Type
 | 
						|
 | 
						|
    # the config of the user mapping provider
 | 
						|
    user_mapping_provider_config: Any
 | 
						|
 | 
						|
    # required attributes to require in userinfo to allow login/registration
 | 
						|
    attribute_requirements: List[SsoAttributeRequirement]
 | 
						|
 | 
						|
    # Whether automatic registrations are enabled in the ODIC flow. Defaults to True
 | 
						|
    enable_registration: bool
 |