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Diffstat (limited to 'synapse/config/oidc.py')
| -rw-r--r-- | synapse/config/oidc.py | 595 |
1 files changed, 595 insertions, 0 deletions
diff --git a/synapse/config/oidc.py b/synapse/config/oidc.py new file mode 100644 index 0000000000..72402eb81d --- /dev/null +++ b/synapse/config/oidc.py @@ -0,0 +1,595 @@ +# Copyright 2020 Quentin Gliech +# Copyright 2020-2021 The Matrix.org Foundation C.I.C. +# +# 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. + +from collections import Counter +from typing import Iterable, List, Mapping, Optional, Tuple, Type + +import attr + +from synapse.config._util import validate_config +from synapse.config.sso import SsoAttributeRequirement +from synapse.python_dependencies import DependencyException, check_requirements +from synapse.types import Collection, JsonDict +from synapse.util.module_loader import load_module +from synapse.util.stringutils import parse_and_validate_mxc_uri + +from ._base import Config, ConfigError, read_file + +DEFAULT_USER_MAPPING_PROVIDER = "synapse.handlers.oidc.JinjaOidcMappingProvider" +# The module that JinjaOidcMappingProvider is in was renamed, we want to +# transparently handle both the same. +LEGACY_USER_MAPPING_PROVIDER = "synapse.handlers.oidc_handler.JinjaOidcMappingProvider" + + +class OIDCConfig(Config): + section = "oidc" + + def read_config(self, config, **kwargs): + self.oidc_providers = tuple(_parse_oidc_provider_configs(config)) + if not self.oidc_providers: + return + + try: + check_requirements("oidc") + except DependencyException as e: + raise ConfigError( + e.message # noqa: B306, DependencyException.message is a property + ) from e + + # check we don't have any duplicate idp_ids now. (The SSO handler will also + # check for duplicates when the REST listeners get registered, but that happens + # after synapse has forked so doesn't give nice errors.) + c = Counter([i.idp_id for i in self.oidc_providers]) + for idp_id, count in c.items(): + if count > 1: + raise ConfigError( + "Multiple OIDC providers have the idp_id %r." % idp_id + ) + + public_baseurl = self.public_baseurl + if public_baseurl is None: + raise ConfigError("oidc_config requires a public_baseurl to be set") + self.oidc_callback_url = public_baseurl + "_synapse/client/oidc/callback" + + @property + def oidc_enabled(self) -> bool: + # OIDC is enabled if we have a provider + return bool(self.oidc_providers) + + def generate_config_section(self, config_dir_path, server_name, **kwargs): + return """\ + # List of OpenID Connect (OIDC) / OAuth 2.0 identity providers, for registration + # and login. + # + # Options for each entry include: + # + # idp_id: a unique identifier for this identity provider. Used internally + # by Synapse; should be a single word such as 'github'. + # + # Note that, if this is changed, users authenticating via that provider + # will no longer be recognised as the same user! + # + # (Use "oidc" here if you are migrating from an old "oidc_config" + # configuration.) + # + # idp_name: A user-facing name for this identity provider, which is used to + # offer the user a choice of login mechanisms. + # + # idp_icon: An optional icon for this identity provider, which is presented + # by clients and Synapse's own IdP picker page. If given, must be an + # MXC URI of the format mxc://<server-name>/<media-id>. (An easy way to + # obtain such an MXC URI is to upload an image to an (unencrypted) room + # and then copy the "url" from the source of the event.) + # + # idp_brand: An optional brand for this identity provider, allowing clients + # to style the login flow according to the identity provider in question. + # See the spec for possible options here. + # + # discover: set to 'false' to disable the use of the OIDC discovery mechanism + # to discover endpoints. Defaults to true. + # + # issuer: Required. The OIDC issuer. Used to validate tokens and (if discovery + # is enabled) to discover the provider's endpoints. + # + # client_id: Required. oauth2 client id to use. + # + # client_secret: oauth2 client secret to use. May be omitted if + # client_secret_jwt_key is given, or if client_auth_method is 'none'. + # + # client_secret_jwt_key: Alternative to client_secret: details of a key used + # to create a JSON Web Token to be used as an OAuth2 client secret. If + # given, must be a dictionary with the following properties: + # + # key: a pem-encoded signing key. Must be a suitable key for the + # algorithm specified. Required unless 'key_file' is given. + # + # key_file: the path to file containing a pem-encoded signing key file. + # Required unless 'key' is given. + # + # jwt_header: a dictionary giving properties to include in the JWT + # header. Must include the key 'alg', giving the algorithm used to + # sign the JWT, such as "ES256", using the JWA identifiers in + # RFC7518. + # + # jwt_payload: an optional dictionary giving properties to include in + # the JWT payload. Normally this should include an 'iss' key. + # + # client_auth_method: auth method to use when exchanging the token. Valid + # values are 'client_secret_basic' (default), 'client_secret_post' and + # 'none'. + # + # scopes: list of scopes to request. This should normally include the "openid" + # scope. Defaults to ["openid"]. + # + # authorization_endpoint: the oauth2 authorization endpoint. Required if + # provider discovery is disabled. + # + # token_endpoint: the oauth2 token endpoint. Required if provider discovery is + # disabled. + # + # userinfo_endpoint: the OIDC userinfo endpoint. Required if discovery is + # disabled and the 'openid' scope is not requested. + # + # jwks_uri: URI where to fetch the JWKS. Required if discovery is disabled and + # the 'openid' scope is used. + # + # skip_verification: set to 'true' to skip metadata verification. Use this if + # you are connecting to a provider that is not OpenID Connect compliant. + # Defaults to false. Avoid this in production. + # + # user_profile_method: Whether to fetch the user profile from the userinfo + # endpoint. Valid values are: 'auto' or 'userinfo_endpoint'. + # + # Defaults to 'auto', which fetches the userinfo endpoint if 'openid' is + # included in 'scopes'. Set to 'userinfo_endpoint' to always fetch the + # userinfo endpoint. + # + # allow_existing_users: set to 'true' to allow a user logging in via OIDC to + # match a pre-existing account instead of failing. This could be used if + # switching from password logins to OIDC. Defaults to false. + # + # user_mapping_provider: Configuration for how attributes returned from a OIDC + # provider are mapped onto a matrix user. This setting has the following + # sub-properties: + # + # module: The class name of a custom mapping module. Default is + # {mapping_provider!r}. + # See https://github.com/matrix-org/synapse/blob/master/docs/sso_mapping_providers.md#openid-mapping-providers + # for information on implementing a custom mapping provider. + # + # config: Configuration for the mapping provider module. This section will + # be passed as a Python dictionary to the user mapping provider + # module's `parse_config` method. + # + # For the default provider, the following settings are available: + # + # subject_claim: name of the claim containing a unique identifier + # for the user. Defaults to 'sub', which OpenID Connect + # compliant providers should provide. + # + # localpart_template: Jinja2 template for the localpart of the MXID. + # If this is not set, the user will be prompted to choose their + # own username (see 'sso_auth_account_details.html' in the 'sso' + # section of this file). + # + # display_name_template: Jinja2 template for the display name to set + # on first login. If unset, no displayname will be set. + # + # email_template: Jinja2 template for the email address of the user. + # If unset, no email address will be added to the account. + # + # extra_attributes: a map of Jinja2 templates for extra attributes + # to send back to the client during login. + # Note that these are non-standard and clients will ignore them + # without modifications. + # + # When rendering, the Jinja2 templates are given a 'user' variable, + # which is set to the claims returned by the UserInfo Endpoint and/or + # in the ID Token. + # + # It is possible to configure Synapse to only allow logins if certain attributes + # match particular values in the OIDC userinfo. The requirements can be listed under + # `attribute_requirements` as shown below. All of the listed attributes must + # match for the login to be permitted. Additional attributes can be added to + # userinfo by expanding the `scopes` section of the OIDC config to retrieve + # additional information from the OIDC provider. + # + # If the OIDC claim is a list, then the attribute must match any value in the list. + # Otherwise, it must exactly match the value of the claim. Using the example + # below, the `family_name` claim MUST be "Stephensson", but the `groups` + # claim MUST contain "admin". + # + # attribute_requirements: + # - attribute: family_name + # value: "Stephensson" + # - attribute: groups + # value: "admin" + # + # See https://github.com/matrix-org/synapse/blob/master/docs/openid.md + # for information on how to configure these options. + # + # For backwards compatibility, it is also possible to configure a single OIDC + # provider via an 'oidc_config' setting. This is now deprecated and admins are + # advised to migrate to the 'oidc_providers' format. (When doing that migration, + # use 'oidc' for the idp_id to ensure that existing users continue to be + # recognised.) + # + oidc_providers: + # Generic example + # + #- idp_id: my_idp + # idp_name: "My OpenID provider" + # idp_icon: "mxc://example.com/mediaid" + # discover: false + # issuer: "https://accounts.example.com/" + # client_id: "provided-by-your-issuer" + # client_secret: "provided-by-your-issuer" + # client_auth_method: client_secret_post + # scopes: ["openid", "profile"] + # authorization_endpoint: "https://accounts.example.com/oauth2/auth" + # token_endpoint: "https://accounts.example.com/oauth2/token" + # userinfo_endpoint: "https://accounts.example.com/userinfo" + # jwks_uri: "https://accounts.example.com/.well-known/jwks.json" + # skip_verification: true + # user_mapping_provider: + # config: + # subject_claim: "id" + # localpart_template: "{{{{ user.login }}}}" + # display_name_template: "{{{{ user.name }}}}" + # email_template: "{{{{ user.email }}}}" + # attribute_requirements: + # - attribute: userGroup + # value: "synapseUsers" + """.format( + mapping_provider=DEFAULT_USER_MAPPING_PROVIDER + ) + + +# jsonschema definition of the configuration settings for an oidc identity provider +OIDC_PROVIDER_CONFIG_SCHEMA = { + "type": "object", + "required": ["issuer", "client_id"], + "properties": { + "idp_id": { + "type": "string", + "minLength": 1, + # MSC2858 allows a maxlen of 255, but we prefix with "oidc-" + "maxLength": 250, + "pattern": "^[A-Za-z0-9._~-]+$", + }, + "idp_name": {"type": "string"}, + "idp_icon": {"type": "string"}, + "idp_brand": { + "type": "string", + "minLength": 1, + "maxLength": 255, + "pattern": "^[a-z][a-z0-9_.-]*$", + }, + "idp_unstable_brand": { + "type": "string", + "minLength": 1, + "maxLength": 255, + "pattern": "^[a-z][a-z0-9_.-]*$", + }, + "discover": {"type": "boolean"}, + "issuer": {"type": "string"}, + "client_id": {"type": "string"}, + "client_secret": {"type": "string"}, + "client_secret_jwt_key": { + "type": "object", + "required": ["jwt_header"], + "oneOf": [ + {"required": ["key"]}, + {"required": ["key_file"]}, + ], + "properties": { + "key": {"type": "string"}, + "key_file": {"type": "string"}, + "jwt_header": { + "type": "object", + "required": ["alg"], + "properties": { + "alg": {"type": "string"}, + }, + "additionalProperties": {"type": "string"}, + }, + "jwt_payload": { + "type": "object", + "additionalProperties": {"type": "string"}, + }, + }, + }, + "client_auth_method": { + "type": "string", + # the following list is the same as the keys of + # authlib.oauth2.auth.ClientAuth.DEFAULT_AUTH_METHODS. We inline it + # to avoid importing authlib here. + "enum": ["client_secret_basic", "client_secret_post", "none"], + }, + "scopes": {"type": "array", "items": {"type": "string"}}, + "authorization_endpoint": {"type": "string"}, + "token_endpoint": {"type": "string"}, + "userinfo_endpoint": {"type": "string"}, + "jwks_uri": {"type": "string"}, + "skip_verification": {"type": "boolean"}, + "user_profile_method": { + "type": "string", + "enum": ["auto", "userinfo_endpoint"], + }, + "allow_existing_users": {"type": "boolean"}, + "user_mapping_provider": {"type": ["object", "null"]}, + "attribute_requirements": { + "type": "array", + "items": SsoAttributeRequirement.JSON_SCHEMA, + }, + }, +} + +# the same as OIDC_PROVIDER_CONFIG_SCHEMA, but with compulsory idp_id and idp_name +OIDC_PROVIDER_CONFIG_WITH_ID_SCHEMA = { + "allOf": [OIDC_PROVIDER_CONFIG_SCHEMA, {"required": ["idp_id", "idp_name"]}] +} + + +# the `oidc_providers` list can either be None (as it is in the default config), or +# a list of provider configs, each of which requires an explicit ID and name. +OIDC_PROVIDER_LIST_SCHEMA = { + "oneOf": [ + {"type": "null"}, + {"type": "array", "items": OIDC_PROVIDER_CONFIG_WITH_ID_SCHEMA}, + ] +} + +# the `oidc_config` setting can either be None (which it used to be in the default +# config), or an object. If an object, it is ignored unless it has an "enabled: True" +# property. +# +# It's *possible* to represent this with jsonschema, but the resultant errors aren't +# particularly clear, so we just check for either an object or a null here, and do +# additional checks in the code. +OIDC_CONFIG_SCHEMA = {"oneOf": [{"type": "null"}, {"type": "object"}]} + +# the top-level schema can contain an "oidc_config" and/or an "oidc_providers". +MAIN_CONFIG_SCHEMA = { + "type": "object", + "properties": { + "oidc_config": OIDC_CONFIG_SCHEMA, + "oidc_providers": OIDC_PROVIDER_LIST_SCHEMA, + }, +} + + +def _parse_oidc_provider_configs(config: JsonDict) -> Iterable["OidcProviderConfig"]: + """extract and parse the OIDC provider configs from the config dict + + The configuration may contain either a single `oidc_config` object with an + `enabled: True` property, or a list of provider configurations under + `oidc_providers`, *or both*. + + Returns a generator which yields the OidcProviderConfig objects + """ + validate_config(MAIN_CONFIG_SCHEMA, config, ()) + + for i, p in enumerate(config.get("oidc_providers") or []): + yield _parse_oidc_config_dict(p, ("oidc_providers", "<item %i>" % (i,))) + + # for backwards-compatibility, it is also possible to provide a single "oidc_config" + # object with an "enabled: True" property. + oidc_config = config.get("oidc_config") + if oidc_config and oidc_config.get("enabled", False): + # MAIN_CONFIG_SCHEMA checks that `oidc_config` is an object, but not that + # it matches OIDC_PROVIDER_CONFIG_SCHEMA (see the comments on OIDC_CONFIG_SCHEMA + # above), so now we need to validate it. + validate_config(OIDC_PROVIDER_CONFIG_SCHEMA, oidc_config, ("oidc_config",)) + yield _parse_oidc_config_dict(oidc_config, ("oidc_config",)) + + +def _parse_oidc_config_dict( + oidc_config: JsonDict, config_path: Tuple[str, ...] +) -> "OidcProviderConfig": + """Take the configuration dict and parse it into an OidcProviderConfig + + Raises: + ConfigError if the configuration is malformed. + """ + ump_config = oidc_config.get("user_mapping_provider", {}) + ump_config.setdefault("module", DEFAULT_USER_MAPPING_PROVIDER) + if ump_config.get("module") == LEGACY_USER_MAPPING_PROVIDER: + ump_config["module"] = DEFAULT_USER_MAPPING_PROVIDER + ump_config.setdefault("config", {}) + + ( + user_mapping_provider_class, + user_mapping_provider_config, + ) = load_module(ump_config, config_path + ("user_mapping_provider",)) + + # Ensure loaded user mapping module has defined all necessary methods + required_methods = [ + "get_remote_user_id", + "map_user_attributes", + ] + missing_methods = [ + method + for method in required_methods + if not hasattr(user_mapping_provider_class, method) + ] + if missing_methods: + raise ConfigError( + "Class %s is missing required " + "methods: %s" + % ( + user_mapping_provider_class, + ", ".join(missing_methods), + ), + config_path + ("user_mapping_provider", "module"), + ) + + idp_id = oidc_config.get("idp_id", "oidc") + + # prefix the given IDP with a prefix specific to the SSO mechanism, to avoid + # clashes with other mechs (such as SAML, CAS). + # + # We allow "oidc" as an exception so that people migrating from old-style + # "oidc_config" format (which has long used "oidc" as its idp_id) can migrate to + # a new-style "oidc_providers" entry without changing the idp_id for their provider + # (and thereby invalidating their user_external_ids data). + + if idp_id != "oidc": + idp_id = "oidc-" + idp_id + + # MSC2858 also specifies that the idp_icon must be a valid MXC uri + idp_icon = oidc_config.get("idp_icon") + if idp_icon is not None: + try: + parse_and_validate_mxc_uri(idp_icon) + except ValueError as e: + raise ConfigError( + "idp_icon must be a valid MXC URI", config_path + ("idp_icon",) + ) from e + + client_secret_jwt_key_config = oidc_config.get("client_secret_jwt_key") + client_secret_jwt_key = None # type: Optional[OidcProviderClientSecretJwtKey] + if client_secret_jwt_key_config is not None: + keyfile = client_secret_jwt_key_config.get("key_file") + if keyfile: + key = read_file(keyfile, config_path + ("client_secret_jwt_key",)) + else: + key = client_secret_jwt_key_config["key"] + client_secret_jwt_key = OidcProviderClientSecretJwtKey( + key=key, + jwt_header=client_secret_jwt_key_config["jwt_header"], + jwt_payload=client_secret_jwt_key_config.get("jwt_payload", {}), + ) + # parse attribute_requirements from config (list of dicts) into a list of SsoAttributeRequirement + attribute_requirements = [ + SsoAttributeRequirement(**x) + for x in oidc_config.get("attribute_requirements", []) + ] + + return OidcProviderConfig( + idp_id=idp_id, + idp_name=oidc_config.get("idp_name", "OIDC"), + idp_icon=idp_icon, + idp_brand=oidc_config.get("idp_brand"), + unstable_idp_brand=oidc_config.get("unstable_idp_brand"), + discover=oidc_config.get("discover", True), + issuer=oidc_config["issuer"], + client_id=oidc_config["client_id"], + client_secret=oidc_config.get("client_secret"), + client_secret_jwt_key=client_secret_jwt_key, + client_auth_method=oidc_config.get("client_auth_method", "client_secret_basic"), + scopes=oidc_config.get("scopes", ["openid"]), + authorization_endpoint=oidc_config.get("authorization_endpoint"), + token_endpoint=oidc_config.get("token_endpoint"), + userinfo_endpoint=oidc_config.get("userinfo_endpoint"), + jwks_uri=oidc_config.get("jwks_uri"), + skip_verification=oidc_config.get("skip_verification", False), + user_profile_method=oidc_config.get("user_profile_method", "auto"), + allow_existing_users=oidc_config.get("allow_existing_users", False), + user_mapping_provider_class=user_mapping_provider_class, + user_mapping_provider_config=user_mapping_provider_config, + attribute_requirements=attribute_requirements, + ) + + +@attr.s(slots=True, frozen=True) +class OidcProviderClientSecretJwtKey: + # a pem-encoded signing key + key = attr.ib(type=str) + + # properties to include in the JWT header + jwt_header = attr.ib(type=Mapping[str, str]) + + # properties to include in the JWT payload. + jwt_payload = attr.ib(type=Mapping[str, str]) + + +@attr.s(slots=True, frozen=True) +class OidcProviderConfig: + # a unique identifier for this identity provider. Used in the 'user_external_ids' + # table, as well as the query/path parameter used in the login protocol. + idp_id = attr.ib(type=str) + + # user-facing name for this identity provider. + idp_name = attr.ib(type=str) + + # Optional MXC URI for icon for this IdP. + idp_icon = attr.ib(type=Optional[str]) + + # Optional brand identifier for this IdP. + idp_brand = attr.ib(type=Optional[str]) + + # Optional brand identifier for the unstable API (see MSC2858). + unstable_idp_brand = attr.ib(type=Optional[str]) + + # whether the OIDC discovery mechanism is used to discover endpoints + discover = attr.ib(type=bool) + + # the OIDC issuer. Used to validate tokens and (if discovery is enabled) to + # discover the provider's endpoints. + issuer = attr.ib(type=str) + + # oauth2 client id to use + client_id = attr.ib(type=str) + + # oauth2 client secret to use. if `None`, use client_secret_jwt_key to generate + # a secret. + client_secret = attr.ib(type=Optional[str]) + + # key to use to construct a JWT to use as a client secret. May be `None` if + # `client_secret` is set. + client_secret_jwt_key = attr.ib(type=Optional[OidcProviderClientSecretJwtKey]) + + # auth method to use when exchanging the token. + # Valid values are 'client_secret_basic', 'client_secret_post' and + # 'none'. + client_auth_method = attr.ib(type=str) + + # list of scopes to request + scopes = attr.ib(type=Collection[str]) + + # the oauth2 authorization endpoint. Required if discovery is disabled. + authorization_endpoint = attr.ib(type=Optional[str]) + + # the oauth2 token endpoint. Required if discovery is disabled. + token_endpoint = attr.ib(type=Optional[str]) + + # the OIDC userinfo endpoint. Required if discovery is disabled and the + # "openid" scope is not requested. + userinfo_endpoint = attr.ib(type=Optional[str]) + + # URI where to fetch the JWKS. Required if discovery is disabled and the + # "openid" scope is used. + jwks_uri = attr.ib(type=Optional[str]) + + # Whether to skip metadata verification + skip_verification = attr.ib(type=bool) + + # Whether to fetch the user profile from the userinfo endpoint. Valid + # values are: "auto" or "userinfo_endpoint". + user_profile_method = attr.ib(type=str) + + # whether to allow a user logging in via OIDC to match a pre-existing account + # instead of failing + allow_existing_users = attr.ib(type=bool) + + # the class of the user mapping provider + user_mapping_provider_class = attr.ib(type=Type) + + # the config of the user mapping provider + user_mapping_provider_config = attr.ib() + + # required attributes to require in userinfo to allow login/registration + attribute_requirements = attr.ib(type=List[SsoAttributeRequirement]) |