Implement MSC2290 (#6043)

Implements MSC2290. This PR adds two new endpoints, /unstable/account/3pid/add and /unstable/account/3pid/bind. Depending on the progress of that MSC the unstable prefix may go away.

This PR also removes the blacklist on some 3PID tests which occurs in #6042, as the corresponding Sytest PR changes them to use the new endpoints.

Finally, it also modifies the account deactivation code such that it doesn't just try to deactivate 3PIDs that were bound to the user's account, but any 3PIDs that were bound through the homeserver on that user's account.

changelog.d/6043.feature

@@ -0,0 +1 @@
+Implement new Client Server API endpoints `/account/3pid/add` and `/account/3pid/bind` as per [MSC2290](https://github.com/matrix-org/matrix-doc/pull/2290).

synapse/handlers/deactivate_account.py

@@ -73,7 +73,9 @@ def deactivate_account(self, user_id, erase_data, id_server=None):
         # unbinding
         identity_server_supports_unbinding = True
 
-        threepids = yield self.store.user_get_threepids(user_id)
+        # Retrieve the 3PIDs this user has bound to an identity server
+        threepids = yield self.store.user_get_bound_threepids(user_id)
+
         for threepid in threepids:
             try:
                 result = yield self._identity_handler.try_unbind_threepid(

synapse/handlers/identity.py

@@ -30,6 +30,7 @@
     HttpResponseException,
     SynapseError,
 )
+from synapse.config.emailconfig import ThreepidBehaviour
 from synapse.util.stringutils import random_string
 
 from ._base import BaseHandler
@@ -45,36 +46,6 @@ def __init__(self, hs):
         self.federation_http_client = hs.get_http_client()
         self.hs = hs
 
-    def _extract_items_from_creds_dict(self, creds):
-        """
-        Retrieve entries from a "credentials" dictionary
-
-        Args:
-            creds (dict[str, str]): Dictionary of credentials that contain the following keys:
-                * client_secret|clientSecret: A unique secret str provided by the client
-                * id_server|idServer: the domain of the identity server to query
-                * id_access_token: The access token to authenticate to the identity
-                    server with.
-
-        Returns:
-            tuple(str, str, str|None): A tuple containing the client_secret, the id_server,
-                and the id_access_token value if available.
-        """
-        client_secret = creds.get("client_secret") or creds.get("clientSecret")
-        if not client_secret:
-            raise SynapseError(
-                400, "No client_secret in creds", errcode=Codes.MISSING_PARAM
-            )
-
-        id_server = creds.get("id_server") or creds.get("idServer")
-        if not id_server:
-            raise SynapseError(
-                400, "No id_server in creds", errcode=Codes.MISSING_PARAM
-            )
-
-        id_access_token = creds.get("id_access_token")
-        return client_secret, id_server, id_access_token
-
     @defer.inlineCallbacks
     def threepid_from_creds(self, id_server, creds):
         """
@@ -113,35 +84,50 @@ def threepid_from_creds(self, id_server, creds):
             data = yield self.http_client.get_json(url, query_params)
         except TimeoutError:
             raise SynapseError(500, "Timed out contacting identity server")
-        return data if "medium" in data else None
+        except HttpResponseException as e:
+            logger.info(
+                "%s returned %i for threepid validation for: %s",
+                id_server,
+                e.code,
+                creds,
+            )
+            return None
+
+        # Old versions of Sydent return a 200 http code even on a failed validation
+        # check. Thus, in addition to the HttpResponseException check above (which
+        # checks for non-200 errors), we need to make sure validation_session isn't
+        # actually an error, identified by the absence of a "medium" key
+        # See https://github.com/matrix-org/sydent/issues/215 for details
+        if "medium" in data:
+            return data
+
+        logger.info("%s reported non-validated threepid: %s", id_server, creds)
+        return None
 
     @defer.inlineCallbacks
-    def bind_threepid(self, creds, mxid, use_v2=True):
+    def bind_threepid(
+        self, client_secret, sid, mxid, id_server, id_access_token=None, use_v2=True
+    ):
         """Bind a 3PID to an identity server
 
         Args:
-            creds (dict[str, str]): Dictionary of credentials that contain the following keys:
-                * client_secret|clientSecret: A unique secret str provided by the client
-                * id_server|idServer: the domain of the identity server to query
-                * id_access_token: The access token to authenticate to the identity
-                    server with. Required if use_v2 is true
+            client_secret (str): A unique secret provided by the client
+
+            sid (str): The ID of the validation session
+
             mxid (str): The MXID to bind the 3PID to
-            use_v2 (bool): Whether to use v2 Identity Service API endpoints
+
+            id_server (str): The domain of the identity server to query
+
+            id_access_token (str): The access token to authenticate to the identity
+                server with, if necessary. Required if use_v2 is true
+
+            use_v2 (bool): Whether to use v2 Identity Service API endpoints. Defaults to True
 
         Returns:
             Deferred[dict]: The response from the identity server
         """
-        logger.debug("binding threepid %r to %s", creds, mxid)
-
-        client_secret, id_server, id_access_token = self._extract_items_from_creds_dict(
-            creds
-        )
-
-        sid = creds.get("sid")
-        if not sid:
-            raise SynapseError(
-                400, "No sid in three_pid_creds", errcode=Codes.MISSING_PARAM
-            )
+        logger.debug("Proxying threepid bind request for %s to %s", mxid, id_server)
 
         # If an id_access_token is not supplied, force usage of v1
         if id_access_token is None:
@@ -160,7 +146,6 @@ def bind_threepid(self, creds, mxid, use_v2=True):
             data = yield self.http_client.post_json_get_json(
                 bind_url, bind_data, headers=headers
             )
-            logger.debug("bound threepid %r to %s", creds, mxid)
 
             # Remember where we bound the threepid
             yield self.store.add_user_bound_threepid(
@@ -182,7 +167,10 @@ def bind_threepid(self, creds, mxid, use_v2=True):
             return data
 
         logger.info("Got 404 when POSTing JSON %s, falling back to v1 URL", bind_url)
-        return (yield self.bind_threepid(creds, mxid, use_v2=False))
+        res = yield self.bind_threepid(
+            client_secret, sid, mxid, id_server, id_access_token, use_v2=False
+        )
+        return res
 
     @defer.inlineCallbacks
     def try_unbind_threepid(self, mxid, threepid):
@@ -459,6 +447,50 @@ def requestMsisdnToken(
         except TimeoutError:
             raise SynapseError(500, "Timed out contacting identity server")
 
+    @defer.inlineCallbacks
+    def validate_threepid_session(self, client_secret, sid):
+        """Validates a threepid session with only the client secret and session ID
+        Tries validating against any configured account_threepid_delegates as well as locally.
+
+        Args:
+            client_secret (str): A secret provided by the client
+
+            sid (str): The ID of the session
+
+        Returns:
+            Dict[str, str|int] if validation was successful, otherwise None
+        """
+        # XXX: We shouldn't need to keep wrapping and unwrapping this value
+        threepid_creds = {"client_secret": client_secret, "sid": sid}
+
+        # We don't actually know which medium this 3PID is. Thus we first assume it's email,
+        # and if validation fails we try msisdn
+        validation_session = None
+
+        # Try to validate as email
+        if self.hs.config.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
+            # Ask our delegated email identity server
+            validation_session = yield self.threepid_from_creds(
+                self.hs.config.account_threepid_delegate_email, threepid_creds
+            )
+        elif self.hs.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
+            # Get a validated session matching these details
+            validation_session = yield self.store.get_threepid_validation_session(
+                "email", client_secret, sid=sid, validated=True
+            )
+
+        if validation_session:
+            return validation_session
+
+        # Try to validate as msisdn
+        if self.hs.config.account_threepid_delegate_msisdn:
+            # Ask our delegated msisdn identity server
+            validation_session = yield self.threepid_from_creds(
+                self.hs.config.account_threepid_delegate_msisdn, threepid_creds
+            )
+
+        return validation_session
+
 
 def create_id_access_token_header(id_access_token):
     """Create an Authorization header for passing to SimpleHttpClient as the header value