diff --git a/changelog.d/7058.feature b/changelog.d/7058.feature new file mode 100644 index 000000000..53ea485e0 --- /dev/null +++ b/changelog.d/7058.feature @@ -0,0 +1 @@ +Render a configurable and comprehensible error page if something goes wrong during the SAML2 authentication process. diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml index 6f6f6fd54..01957a90d 100644 --- a/docs/sample_config.yaml +++ b/docs/sample_config.yaml @@ -1347,6 +1347,13 @@ saml2_config: # #grandfathered_mxid_source_attribute: upn + # Path to a file containing HTML content to serve in case an error happens + # when the user gets redirected from the SAML IdP back to Synapse. + # If no file is provided, this defaults to some minimalistic HTML telling the + # user that something went wrong and they should try authenticating again. + # + #error_html_path: /path/to/static/content/saml_error.html + # Enable CAS for registration and login. diff --git a/synapse/config/saml2_config.py b/synapse/config/saml2_config.py index 423c158b1..07895c431 100644 --- a/synapse/config/saml2_config.py +++ b/synapse/config/saml2_config.py @@ -27,6 +27,18 @@ DEFAULT_USER_MAPPING_PROVIDER = ( "synapse.handlers.saml_handler.DefaultSamlMappingProvider" ) +SAML2_ERROR_DEFAULT_HTML = """ + + +

Oops! Something went wrong

+

+ Try logging in again from your Matrix client and if the problem persists + please contact the server's administrator. +

+ + +""" + def _dict_merge(merge_dict, into_dict): """Do a deep merge of two dicts @@ -160,6 +172,13 @@ class SAML2Config(Config): saml2_config.get("saml_session_lifetime", "5m") ) + if "error_html_path" in config: + self.saml2_error_html_content = self.read_file( + config["error_html_path"], "saml2_config.error_html_path", + ) + else: + self.saml2_error_html_content = SAML2_ERROR_DEFAULT_HTML + def _default_saml_config_dict( self, required_attributes: set, optional_attributes: set ): @@ -325,6 +344,13 @@ class SAML2Config(Config): # The default is 'uid'. # #grandfathered_mxid_source_attribute: upn + + # Path to a file containing HTML content to serve in case an error happens + # when the user gets redirected from the SAML IdP back to Synapse. + # If no file is provided, this defaults to some minimalistic HTML telling the + # user that something went wrong and they should try authenticating again. + # + #error_html_path: /path/to/static/content/saml_error.html """ % { "config_dir_path": config_dir_path } diff --git a/synapse/handlers/saml_handler.py b/synapse/handlers/saml_handler.py index 940675339..72c109981 100644 --- a/synapse/handlers/saml_handler.py +++ b/synapse/handlers/saml_handler.py @@ -23,6 +23,7 @@ from saml2.client import Saml2Client from synapse.api.errors import SynapseError from synapse.config import ConfigError +from synapse.http.server import finish_request from synapse.http.servlet import parse_string from synapse.module_api import ModuleApi from synapse.types import ( @@ -73,6 +74,8 @@ class SamlHandler: # a lock on the mappings self._mapping_lock = Linearizer(name="saml_mapping", clock=self._clock) + self._error_html_content = hs.config.saml2_error_html_content + def handle_redirect_request(self, client_redirect_url): """Handle an incoming request to /login/sso/redirect @@ -114,7 +117,22 @@ class SamlHandler: # the dict. self.expire_sessions() - user_id = await self._map_saml_response_to_user(resp_bytes, relay_state) + try: + user_id = await self._map_saml_response_to_user(resp_bytes, relay_state) + except Exception as e: + # If decoding the response or mapping it to a user failed, then log the + # error and tell the user that something went wrong. + logger.error(e) + + request.setResponseCode(400) + request.setHeader(b"Content-Type", b"text/html; charset=utf-8") + request.setHeader( + b"Content-Length", b"%d" % (len(self._error_html_content),) + ) + request.write(self._error_html_content.encode("utf8")) + finish_request(request) + return + self._auth_handler.complete_sso_login(user_id, request, relay_state) async def _map_saml_response_to_user(self, resp_bytes, client_redirect_url): diff --git a/synapse/logging/context.py b/synapse/logging/context.py index 1eccc0e83..860b99a4c 100644 --- a/synapse/logging/context.py +++ b/synapse/logging/context.py @@ -210,7 +210,7 @@ class LoggingContext(object): class Sentinel(object): """Sentinel to represent the root context""" - __slots__ = ["previous_context", "alive", "request", "scope"] + __slots__ = ["previous_context", "alive", "request", "scope", "tag"] def __init__(self) -> None: # Minimal set for compatibility with LoggingContext @@ -218,6 +218,7 @@ class LoggingContext(object): self.alive = None self.request = None self.scope = None + self.tag = None def __str__(self): return "sentinel" @@ -511,7 +512,7 @@ class PreserveLoggingContext(object): __slots__ = ["current_context", "new_context", "has_parent"] - def __init__(self, new_context: Optional[LoggingContext] = None) -> None: + def __init__(self, new_context: Optional[LoggingContextOrSentinel] = None) -> None: if new_context is None: self.new_context = LoggingContext.sentinel # type: LoggingContextOrSentinel else: diff --git a/synapse/rest/saml2/response_resource.py b/synapse/rest/saml2/response_resource.py index 69ecc5e4b..a545c13db 100644 --- a/synapse/rest/saml2/response_resource.py +++ b/synapse/rest/saml2/response_resource.py @@ -14,7 +14,11 @@ # See the License for the specific language governing permissions and # limitations under the License. -from synapse.http.server import DirectServeResource, wrap_html_request_handler +from synapse.http.server import ( + DirectServeResource, + finish_request, + wrap_html_request_handler, +) class SAML2ResponseResource(DirectServeResource): @@ -24,8 +28,20 @@ class SAML2ResponseResource(DirectServeResource): def __init__(self, hs): super().__init__() + self._error_html_content = hs.config.saml2_error_html_content self._saml_handler = hs.get_saml_handler() + async def _async_render_GET(self, request): + # We're not expecting any GET request on that resource if everything goes right, + # but some IdPs sometimes end up responding with a 302 redirect on this endpoint. + # In this case, just tell the user that something went wrong and they should + # try to authenticate again. + request.setResponseCode(400) + request.setHeader(b"Content-Type", b"text/html; charset=utf-8") + request.setHeader(b"Content-Length", b"%d" % (len(self._error_html_content),)) + request.write(self._error_html_content.encode("utf8")) + finish_request(request) + @wrap_html_request_handler async def _async_render_POST(self, request): return await self._saml_handler.handle_saml_response(request) diff --git a/synapse/storage/database.py b/synapse/storage/database.py index 609db4061..e61595336 100644 --- a/synapse/storage/database.py +++ b/synapse/storage/database.py @@ -29,7 +29,11 @@ from twisted.internet import defer from synapse.api.errors import StoreError from synapse.config.database import DatabaseConnectionConfig -from synapse.logging.context import LoggingContext, make_deferred_yieldable +from synapse.logging.context import ( + LoggingContext, + LoggingContextOrSentinel, + make_deferred_yieldable, +) from synapse.metrics.background_process_metrics import run_as_background_process from synapse.storage.background_updates import BackgroundUpdater from synapse.storage.engines import BaseDatabaseEngine, PostgresEngine, Sqlite3Engine @@ -543,7 +547,9 @@ class Database(object): Returns: Deferred: The result of func """ - parent_context = LoggingContext.current_context() + parent_context = ( + LoggingContext.current_context() + ) # type: Optional[LoggingContextOrSentinel] if parent_context == LoggingContext.sentinel: logger.warning( "Starting db connection from sentinel context: metrics will be lost"