MatrixSynapse/synapse/config/oidc.py

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# 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 Any, Collection, 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 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) -> None:
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.root.server.public_baseurl
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) -> str:
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://matrix-org.github.io/synapse/latest/sso_mapping_providers.html#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://matrix-org.github.io/synapse/latest/openid.html
# 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._~-]+$",
},
"idp_name": {"type": "string"},
"idp_icon": {"type": "string"},
"idp_brand": {
"type": "string",
"minLength": 1,
"maxLength": 255,
"pattern": "^[a-z][a-z0-9_.-]*$",
},
"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: Optional[OidcProviderClientSecretJwtKey] = None
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"),
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, auto_attribs=True)
class OidcProviderClientSecretJwtKey:
# a pem-encoded signing key
key: str
# properties to include in the JWT header
jwt_header: Mapping[str, str]
# properties to include in the JWT payload.
jwt_payload: Mapping[str, str]
@attr.s(slots=True, frozen=True, auto_attribs=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: str
# user-facing name for this identity provider.
idp_name: str
# Optional MXC URI for icon for this IdP.
idp_icon: Optional[str]
# Optional brand identifier for this IdP.
idp_brand: Optional[str]
# whether the OIDC discovery mechanism is used to discover endpoints
discover: bool
# the OIDC issuer. Used to validate tokens and (if discovery is enabled) to
# discover the provider's endpoints.
issuer: str
# oauth2 client id to use
client_id: str
# oauth2 client secret to use. if `None`, use client_secret_jwt_key to generate
# a secret.
client_secret: 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: Optional[OidcProviderClientSecretJwtKey]
# auth method to use when exchanging the token.
# Valid values are 'client_secret_basic', 'client_secret_post' and
# 'none'.
client_auth_method: str
# list of scopes to request
scopes: Collection[str]
# the oauth2 authorization endpoint. Required if discovery is disabled.
authorization_endpoint: Optional[str]
# the oauth2 token endpoint. Required if discovery is disabled.
token_endpoint: Optional[str]
# the OIDC userinfo endpoint. Required if discovery is disabled and the
# "openid" scope is not requested.
userinfo_endpoint: Optional[str]
# URI where to fetch the JWKS. Required if discovery is disabled and the
# "openid" scope is used.
jwks_uri: Optional[str]
# 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]