diff --git a/synapse/handlers/oidc_handler.py b/synapse/handlers/oidc_handler.py
index 84754e5c9c..d6347bb1b8 100644
--- a/synapse/handlers/oidc_handler.py
+++ b/synapse/handlers/oidc_handler.py
@@ -35,6 +35,7 @@ from typing_extensions import TypedDict
from twisted.web.client import readBody
from synapse.config import ConfigError
+from synapse.config.oidc_config import OidcProviderConfig
from synapse.handlers.sso import MappingException, UserAttributes
from synapse.http.site import SynapseRequest
from synapse.logging.context import make_deferred_yieldable
@@ -70,6 +71,131 @@ JWK = Dict[str, str]
JWKS = TypedDict("JWKS", {"keys": List[JWK]})
+class OidcHandler:
+ """Handles requests related to the OpenID Connect login flow.
+ """
+
+ def __init__(self, hs: "HomeServer"):
+ self._sso_handler = hs.get_sso_handler()
+
+ provider_conf = hs.config.oidc.oidc_provider
+ # we should not have been instantiated if there is no configured provider.
+ assert provider_conf is not None
+
+ self._token_generator = OidcSessionTokenGenerator(hs)
+
+ self._provider = OidcProvider(hs, self._token_generator, provider_conf)
+
+ async def load_metadata(self) -> None:
+ """Validate the config and load the metadata from the remote endpoint.
+
+ Called at startup to ensure we have everything we need.
+ """
+ await self._provider.load_metadata()
+ await self._provider.load_jwks()
+
+ async def handle_oidc_callback(self, request: SynapseRequest) -> None:
+ """Handle an incoming request to /_synapse/oidc/callback
+
+ Since we might want to display OIDC-related errors in a user-friendly
+ way, we don't raise SynapseError from here. Instead, we call
+ ``self._sso_handler.render_error`` which displays an HTML page for the error.
+
+ Most of the OpenID Connect logic happens here:
+
+ - first, we check if there was any error returned by the provider and
+ display it
+ - then we fetch the session cookie, decode and verify it
+ - the ``state`` query parameter should match with the one stored in the
+ session cookie
+
+ Once we know the session is legit, we then delegate to the OIDC Provider
+ implementation, which will exchange the code with the provider and complete the
+ login/authentication.
+
+ Args:
+ request: the incoming request from the browser.
+ """
+
+ # The provider might redirect with an error.
+ # In that case, just display it as-is.
+ if b"error" in request.args:
+ # error response from the auth server. see:
+ # https://tools.ietf.org/html/rfc6749#section-4.1.2.1
+ # https://openid.net/specs/openid-connect-core-1_0.html#AuthError
+ error = request.args[b"error"][0].decode()
+ description = request.args.get(b"error_description", [b""])[0].decode()
+
+ # Most of the errors returned by the provider could be due by
+ # either the provider misbehaving or Synapse being misconfigured.
+ # The only exception of that is "access_denied", where the user
+ # probably cancelled the login flow. In other cases, log those errors.
+ if error != "access_denied":
+ logger.error("Error from the OIDC provider: %s %s", error, description)
+
+ self._sso_handler.render_error(request, error, description)
+ return
+
+ # otherwise, it is presumably a successful response. see:
+ # https://tools.ietf.org/html/rfc6749#section-4.1.2
+
+ # Fetch the session cookie
+ session = request.getCookie(SESSION_COOKIE_NAME) # type: Optional[bytes]
+ if session is None:
+ logger.info("No session cookie found")
+ self._sso_handler.render_error(
+ request, "missing_session", "No session cookie found"
+ )
+ return
+
+ # Remove the cookie. There is a good chance that if the callback failed
+ # once, it will fail next time and the code will already be exchanged.
+ # Removing it early avoids spamming the provider with token requests.
+ request.addCookie(
+ SESSION_COOKIE_NAME,
+ b"",
+ path="/_synapse/oidc",
+ expires="Thu, Jan 01 1970 00:00:00 UTC",
+ httpOnly=True,
+ sameSite="lax",
+ )
+
+ # Check for the state query parameter
+ if b"state" not in request.args:
+ logger.info("State parameter is missing")
+ self._sso_handler.render_error(
+ request, "invalid_request", "State parameter is missing"
+ )
+ return
+
+ state = request.args[b"state"][0].decode()
+
+ # Deserialize the session token and verify it.
+ try:
+ session_data = self._token_generator.verify_oidc_session_token(
+ session, state
+ )
+ except MacaroonDeserializationException as e:
+ logger.exception("Invalid session")
+ self._sso_handler.render_error(request, "invalid_session", str(e))
+ return
+ except MacaroonInvalidSignatureException as e:
+ logger.exception("Could not verify session")
+ self._sso_handler.render_error(request, "mismatching_session", str(e))
+ return
+
+ if b"code" not in request.args:
+ logger.info("Code parameter is missing")
+ self._sso_handler.render_error(
+ request, "invalid_request", "Code parameter is missing"
+ )
+ return
+
+ code = request.args[b"code"][0].decode()
+
+ await self._provider.handle_oidc_callback(request, session_data, code)
+
+
class OidcError(Exception):
"""Used to catch errors when calling the token_endpoint
"""
@@ -84,21 +210,25 @@ class OidcError(Exception):
return self.error
-class OidcHandler:
- """Handles requests related to the OpenID Connect login flow.
+class OidcProvider:
+ """Wraps the config for a single OIDC IdentityProvider
+
+ Provides methods for handling redirect requests and callbacks via that particular
+ IdP.
"""
- def __init__(self, hs: "HomeServer"):
+ def __init__(
+ self,
+ hs: "HomeServer",
+ token_generator: "OidcSessionTokenGenerator",
+ provider: OidcProviderConfig,
+ ):
self._store = hs.get_datastore()
- self._token_generator = OidcSessionTokenGenerator(hs)
+ self._token_generator = token_generator
self._callback_url = hs.config.oidc_callback_url # type: str
- provider = hs.config.oidc.oidc_provider
- # we should not have been instantiated if there is no configured provider.
- assert provider is not None
-
self._scopes = provider.scopes
self._user_profile_method = provider.user_profile_method
self._client_auth = ClientAuth(
@@ -552,22 +682,16 @@ class OidcHandler:
nonce=nonce,
)
- async def handle_oidc_callback(self, request: SynapseRequest) -> None:
+ async def handle_oidc_callback(
+ self, request: SynapseRequest, session_data: "OidcSessionData", code: str
+ ) -> None:
"""Handle an incoming request to /_synapse/oidc/callback
- Since we might want to display OIDC-related errors in a user-friendly
- way, we don't raise SynapseError from here. Instead, we call
- ``self._sso_handler.render_error`` which displays an HTML page for the error.
+ By this time we have already validated the session on the synapse side, and
+ now need to do the provider-specific operations. This includes:
- Most of the OpenID Connect logic happens here:
-
- - first, we check if there was any error returned by the provider and
- display it
- - then we fetch the session cookie, decode and verify it
- - the ``state`` query parameter should match with the one stored in the
- session cookie
- - once we known this session is legit, exchange the code with the
- provider using the ``token_endpoint`` (see ``_exchange_code``)
+ - exchange the code with the provider using the ``token_endpoint`` (see
+ ``_exchange_code``)
- once we have the token, use it to either extract the UserInfo from
the ``id_token`` (``_parse_id_token``), or use the ``access_token``
to fetch UserInfo from the ``userinfo_endpoint``
@@ -577,86 +701,12 @@ class OidcHandler:
Args:
request: the incoming request from the browser.
+ session_data: the session data, extracted from our cookie
+ code: The authorization code we got from the callback.
"""
-
- # The provider might redirect with an error.
- # In that case, just display it as-is.
- if b"error" in request.args:
- # error response from the auth server. see:
- # https://tools.ietf.org/html/rfc6749#section-4.1.2.1
- # https://openid.net/specs/openid-connect-core-1_0.html#AuthError
- error = request.args[b"error"][0].decode()
- description = request.args.get(b"error_description", [b""])[0].decode()
-
- # Most of the errors returned by the provider could be due by
- # either the provider misbehaving or Synapse being misconfigured.
- # The only exception of that is "access_denied", where the user
- # probably cancelled the login flow. In other cases, log those errors.
- if error != "access_denied":
- logger.error("Error from the OIDC provider: %s %s", error, description)
-
- self._sso_handler.render_error(request, error, description)
- return
-
- # otherwise, it is presumably a successful response. see:
- # https://tools.ietf.org/html/rfc6749#section-4.1.2
-
- # Fetch the session cookie
- session = request.getCookie(SESSION_COOKIE_NAME) # type: Optional[bytes]
- if session is None:
- logger.info("No session cookie found")
- self._sso_handler.render_error(
- request, "missing_session", "No session cookie found"
- )
- return
-
- # Remove the cookie. There is a good chance that if the callback failed
- # once, it will fail next time and the code will already be exchanged.
- # Removing it early avoids spamming the provider with token requests.
- request.addCookie(
- SESSION_COOKIE_NAME,
- b"",
- path="/_synapse/oidc",
- expires="Thu, Jan 01 1970 00:00:00 UTC",
- httpOnly=True,
- sameSite="lax",
- )
-
- # Check for the state query parameter
- if b"state" not in request.args:
- logger.info("State parameter is missing")
- self._sso_handler.render_error(
- request, "invalid_request", "State parameter is missing"
- )
- return
-
- state = request.args[b"state"][0].decode()
-
- # Deserialize the session token and verify it.
- try:
- session_data = self._token_generator.verify_oidc_session_token(
- session, state
- )
- except MacaroonDeserializationException as e:
- logger.exception("Invalid session")
- self._sso_handler.render_error(request, "invalid_session", str(e))
- return
- except MacaroonInvalidSignatureException as e:
- logger.exception("Could not verify session")
- self._sso_handler.render_error(request, "mismatching_session", str(e))
- return
-
# Exchange the code with the provider
- if b"code" not in request.args:
- logger.info("Code parameter is missing")
- self._sso_handler.render_error(
- request, "invalid_request", "Code parameter is missing"
- )
- return
-
- logger.debug("Exchanging code")
- code = request.args[b"code"][0].decode()
try:
+ logger.debug("Exchanging code")
token = await self._exchange_code(code)
except OidcError as e:
logger.exception("Could not exchange code")
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