198 lines
11 KiB
Markdown
198 lines
11 KiB
Markdown
# SSO Mapping Providers
|
|
|
|
A mapping provider is a Python class (loaded via a Python module) that
|
|
works out how to map attributes of a SSO response to Matrix-specific
|
|
user attributes. Details such as user ID localpart, displayname, and even avatar
|
|
URLs are all things that can be mapped from talking to a SSO service.
|
|
|
|
As an example, a SSO service may return the email address
|
|
"john.smith@example.com" for a user, whereas Synapse will need to figure out how
|
|
to turn that into a displayname when creating a Matrix user for this individual.
|
|
It may choose `John Smith`, or `Smith, John [Example.com]` or any number of
|
|
variations. As each Synapse configuration may want something different, this is
|
|
where SAML mapping providers come into play.
|
|
|
|
SSO mapping providers are currently supported for OpenID and SAML SSO
|
|
configurations. Please see the details below for how to implement your own.
|
|
|
|
It is up to the mapping provider whether the user should be assigned a predefined
|
|
Matrix ID based on the SSO attributes, or if the user should be allowed to
|
|
choose their own username.
|
|
|
|
In the first case - where users are automatically allocated a Matrix ID - it is
|
|
the responsibility of the mapping provider to normalise the SSO attributes and
|
|
map them to a valid Matrix ID. The [specification for Matrix
|
|
IDs](https://matrix.org/docs/spec/appendices#user-identifiers) has some
|
|
information about what is considered valid.
|
|
|
|
If the mapping provider does not assign a Matrix ID, then Synapse will
|
|
automatically serve an HTML page allowing the user to pick their own username.
|
|
|
|
External mapping providers are provided to Synapse in the form of an external
|
|
Python module. You can retrieve this module from [PyPI](https://pypi.org) or elsewhere,
|
|
but it must be importable via Synapse (e.g. it must be in the same virtualenv
|
|
as Synapse). The Synapse config is then modified to point to the mapping provider
|
|
(and optionally provide additional configuration for it).
|
|
|
|
## OpenID Mapping Providers
|
|
|
|
The OpenID mapping provider can be customized by editing the
|
|
`oidc_config.user_mapping_provider.module` config option.
|
|
|
|
`oidc_config.user_mapping_provider.config` allows you to provide custom
|
|
configuration options to the module. Check with the module's documentation for
|
|
what options it provides (if any). The options listed by default are for the
|
|
user mapping provider built in to Synapse. If using a custom module, you should
|
|
comment these options out and use those specified by the module instead.
|
|
|
|
### Building a Custom OpenID Mapping Provider
|
|
|
|
A custom mapping provider must specify the following methods:
|
|
|
|
* `__init__(self, parsed_config)`
|
|
- Arguments:
|
|
- `parsed_config` - A configuration object that is the return value of the
|
|
`parse_config` method. You should set any configuration options needed by
|
|
the module here.
|
|
* `parse_config(config)`
|
|
- This method should have the `@staticmethod` decoration.
|
|
- Arguments:
|
|
- `config` - A `dict` representing the parsed content of the
|
|
`oidc_config.user_mapping_provider.config` homeserver config option.
|
|
Runs on homeserver startup. Providers should extract and validate
|
|
any option values they need here.
|
|
- Whatever is returned will be passed back to the user mapping provider module's
|
|
`__init__` method during construction.
|
|
* `get_remote_user_id(self, userinfo)`
|
|
- Arguments:
|
|
- `userinfo` - A `authlib.oidc.core.claims.UserInfo` object to extract user
|
|
information from.
|
|
- This method must return a string, which is the unique, immutable identifier
|
|
for the user. Commonly the `sub` claim of the response.
|
|
* `map_user_attributes(self, userinfo, token, failures)`
|
|
- This method must be async.
|
|
- Arguments:
|
|
- `userinfo` - A `authlib.oidc.core.claims.UserInfo` object to extract user
|
|
information from.
|
|
- `token` - A dictionary which includes information necessary to make
|
|
further requests to the OpenID provider.
|
|
- `failures` - An `int` that represents the amount of times the returned
|
|
mxid localpart mapping has failed. This should be used
|
|
to create a deduplicated mxid localpart which should be
|
|
returned instead. For example, if this method returns
|
|
`john.doe` as the value of `localpart` in the returned
|
|
dict, and that is already taken on the homeserver, this
|
|
method will be called again with the same parameters but
|
|
with failures=1. The method should then return a different
|
|
`localpart` value, such as `john.doe1`.
|
|
- Returns a dictionary with two keys:
|
|
- `localpart`: A string, used to generate the Matrix ID. If this is
|
|
`None`, the user is prompted to pick their own username. This is only used
|
|
during a user's first login. Once a localpart has been associated with a
|
|
remote user ID (see `get_remote_user_id`) it cannot be updated.
|
|
- `displayname`: An optional string, the display name for the user.
|
|
* `get_extra_attributes(self, userinfo, token)`
|
|
- This method must be async.
|
|
- Arguments:
|
|
- `userinfo` - A `authlib.oidc.core.claims.UserInfo` object to extract user
|
|
information from.
|
|
- `token` - A dictionary which includes information necessary to make
|
|
further requests to the OpenID provider.
|
|
- Returns a dictionary that is suitable to be serialized to JSON. This
|
|
will be returned as part of the response during a successful login.
|
|
|
|
Note that care should be taken to not overwrite any of the parameters
|
|
usually returned as part of the [login response](https://matrix.org/docs/spec/client_server/latest#post-matrix-client-r0-login).
|
|
|
|
### Default OpenID Mapping Provider
|
|
|
|
Synapse has a built-in OpenID mapping provider if a custom provider isn't
|
|
specified in the config. It is located at
|
|
[`synapse.handlers.oidc.JinjaOidcMappingProvider`](https://github.com/matrix-org/synapse/blob/develop/synapse/handlers/oidc.py).
|
|
|
|
## SAML Mapping Providers
|
|
|
|
The SAML mapping provider can be customized by editing the
|
|
`saml2_config.user_mapping_provider.module` config option.
|
|
|
|
`saml2_config.user_mapping_provider.config` allows you to provide custom
|
|
configuration options to the module. Check with the module's documentation for
|
|
what options it provides (if any). The options listed by default are for the
|
|
user mapping provider built in to Synapse. If using a custom module, you should
|
|
comment these options out and use those specified by the module instead.
|
|
|
|
### Building a Custom SAML Mapping Provider
|
|
|
|
A custom mapping provider must specify the following methods:
|
|
|
|
* `__init__(self, parsed_config, module_api)`
|
|
- Arguments:
|
|
- `parsed_config` - A configuration object that is the return value of the
|
|
`parse_config` method. You should set any configuration options needed by
|
|
the module here.
|
|
- `module_api` - a `synapse.module_api.ModuleApi` object which provides the
|
|
stable API available for extension modules.
|
|
* `parse_config(config)`
|
|
- This method should have the `@staticmethod` decoration.
|
|
- Arguments:
|
|
- `config` - A `dict` representing the parsed content of the
|
|
`saml_config.user_mapping_provider.config` homeserver config option.
|
|
Runs on homeserver startup. Providers should extract and validate
|
|
any option values they need here.
|
|
- Whatever is returned will be passed back to the user mapping provider module's
|
|
`__init__` method during construction.
|
|
* `get_saml_attributes(config)`
|
|
- This method should have the `@staticmethod` decoration.
|
|
- Arguments:
|
|
- `config` - A object resulting from a call to `parse_config`.
|
|
- Returns a tuple of two sets. The first set equates to the SAML auth
|
|
response attributes that are required for the module to function, whereas
|
|
the second set consists of those attributes which can be used if available,
|
|
but are not necessary.
|
|
* `get_remote_user_id(self, saml_response, client_redirect_url)`
|
|
- Arguments:
|
|
- `saml_response` - A `saml2.response.AuthnResponse` object to extract user
|
|
information from.
|
|
- `client_redirect_url` - A string, the URL that the client will be
|
|
redirected to.
|
|
- This method must return a string, which is the unique, immutable identifier
|
|
for the user. Commonly the `uid` claim of the response.
|
|
* `saml_response_to_user_attributes(self, saml_response, failures, client_redirect_url)`
|
|
- Arguments:
|
|
- `saml_response` - A `saml2.response.AuthnResponse` object to extract user
|
|
information from.
|
|
- `failures` - An `int` that represents the amount of times the returned
|
|
mxid localpart mapping has failed. This should be used
|
|
to create a deduplicated mxid localpart which should be
|
|
returned instead. For example, if this method returns
|
|
`john.doe` as the value of `mxid_localpart` in the returned
|
|
dict, and that is already taken on the homeserver, this
|
|
method will be called again with the same parameters but
|
|
with failures=1. The method should then return a different
|
|
`mxid_localpart` value, such as `john.doe1`.
|
|
- `client_redirect_url` - A string, the URL that the client will be
|
|
redirected to.
|
|
- This method must return a dictionary, which will then be used by Synapse
|
|
to build a new user. The following keys are allowed:
|
|
* `mxid_localpart` - A string, the mxid localpart of the new user. If this is
|
|
`None`, the user is prompted to pick their own username. This is only used
|
|
during a user's first login. Once a localpart has been associated with a
|
|
remote user ID (see `get_remote_user_id`) it cannot be updated.
|
|
* `displayname` - The displayname of the new user. If not provided, will default to
|
|
the value of `mxid_localpart`.
|
|
* `emails` - A list of emails for the new user. If not provided, will
|
|
default to an empty list.
|
|
|
|
Alternatively it can raise a `synapse.api.errors.RedirectException` to
|
|
redirect the user to another page. This is useful to prompt the user for
|
|
additional information, e.g. if you want them to provide their own username.
|
|
It is the responsibility of the mapping provider to either redirect back
|
|
to `client_redirect_url` (including any additional information) or to
|
|
complete registration using methods from the `ModuleApi`.
|
|
|
|
### Default SAML Mapping Provider
|
|
|
|
Synapse has a built-in SAML mapping provider if a custom provider isn't
|
|
specified in the config. It is located at
|
|
[`synapse.handlers.saml.DefaultSamlMappingProvider`](https://github.com/matrix-org/synapse/blob/develop/synapse/handlers/saml.py).
|