From be76cd8200b18f3c68b895f85ac7ef5b0ddc2466 Mon Sep 17 00:00:00 2001
From: Brendan Abolivier <babolivier@matrix.org>
Date: Thu, 29 Sep 2022 14:23:24 +0100
Subject: Allow admins to require a manual approval process before new accounts
 can be used (using MSC3866) (#13556)

---
 synapse/rest/client/login.py    | 37 ++++++++++++++++++++++++++++++++++---
 synapse/rest/client/register.py | 22 ++++++++++++++++++++--
 2 files changed, 54 insertions(+), 5 deletions(-)

(limited to 'synapse/rest/client')

diff --git a/synapse/rest/client/login.py b/synapse/rest/client/login.py
index 0437c87d8d..f554586ac3 100644
--- a/synapse/rest/client/login.py
+++ b/synapse/rest/client/login.py
@@ -28,7 +28,14 @@ from typing import (
 
 from typing_extensions import TypedDict
 
-from synapse.api.errors import Codes, InvalidClientTokenError, LoginError, SynapseError
+from synapse.api.constants import ApprovalNoticeMedium
+from synapse.api.errors import (
+    Codes,
+    InvalidClientTokenError,
+    LoginError,
+    NotApprovedError,
+    SynapseError,
+)
 from synapse.api.ratelimiting import Ratelimiter
 from synapse.api.urls import CLIENT_API_PREFIX
 from synapse.appservice import ApplicationService
@@ -55,11 +62,11 @@ logger = logging.getLogger(__name__)
 
 class LoginResponse(TypedDict, total=False):
     user_id: str
-    access_token: str
+    access_token: Optional[str]
     home_server: str
     expires_in_ms: Optional[int]
     refresh_token: Optional[str]
-    device_id: str
+    device_id: Optional[str]
     well_known: Optional[Dict[str, Any]]
 
 
@@ -92,6 +99,12 @@ class LoginRestServlet(RestServlet):
             hs.config.registration.refreshable_access_token_lifetime is not None
         )
 
+        # Whether we need to check if the user has been approved or not.
+        self._require_approval = (
+            hs.config.experimental.msc3866.enabled
+            and hs.config.experimental.msc3866.require_approval_for_new_accounts
+        )
+
         self.auth = hs.get_auth()
 
         self.clock = hs.get_clock()
@@ -220,6 +233,14 @@ class LoginRestServlet(RestServlet):
         except KeyError:
             raise SynapseError(400, "Missing JSON keys.")
 
+        if self._require_approval:
+            approved = await self.auth_handler.is_user_approved(result["user_id"])
+            if not approved:
+                raise NotApprovedError(
+                    msg="This account is pending approval by a server administrator.",
+                    approval_notice_medium=ApprovalNoticeMedium.NONE,
+                )
+
         well_known_data = self._well_known_builder.get_well_known()
         if well_known_data:
             result["well_known"] = well_known_data
@@ -356,6 +377,16 @@ class LoginRestServlet(RestServlet):
                 errcode=Codes.INVALID_PARAM,
             )
 
+        if self._require_approval:
+            approved = await self.auth_handler.is_user_approved(user_id)
+            if not approved:
+                # If the user isn't approved (and needs to be) we won't allow them to
+                # actually log in, so we don't want to create a device/access token.
+                return LoginResponse(
+                    user_id=user_id,
+                    home_server=self.hs.hostname,
+                )
+
         initial_display_name = login_submission.get("initial_device_display_name")
         (
             device_id,
diff --git a/synapse/rest/client/register.py b/synapse/rest/client/register.py
index 20bab20c8f..de810ae3ec 100644
--- a/synapse/rest/client/register.py
+++ b/synapse/rest/client/register.py
@@ -21,10 +21,15 @@ from twisted.web.server import Request
 import synapse
 import synapse.api.auth
 import synapse.types
-from synapse.api.constants import APP_SERVICE_REGISTRATION_TYPE, LoginType
+from synapse.api.constants import (
+    APP_SERVICE_REGISTRATION_TYPE,
+    ApprovalNoticeMedium,
+    LoginType,
+)
 from synapse.api.errors import (
     Codes,
     InteractiveAuthIncompleteError,
+    NotApprovedError,
     SynapseError,
     ThreepidValidationError,
     UnrecognizedRequestError,
@@ -414,6 +419,11 @@ class RegisterRestServlet(RestServlet):
             hs.config.registration.inhibit_user_in_use_error
         )
 
+        self._require_approval = (
+            hs.config.experimental.msc3866.enabled
+            and hs.config.experimental.msc3866.require_approval_for_new_accounts
+        )
+
         self._registration_flows = _calculate_registration_flows(
             hs.config, self.auth_handler
         )
@@ -734,6 +744,12 @@ class RegisterRestServlet(RestServlet):
                 access_token=return_dict.get("access_token"),
             )
 
+            if self._require_approval:
+                raise NotApprovedError(
+                    msg="This account needs to be approved by an administrator before it can be used.",
+                    approval_notice_medium=ApprovalNoticeMedium.NONE,
+                )
+
         return 200, return_dict
 
     async def _do_appservice_registration(
@@ -778,7 +794,9 @@ class RegisterRestServlet(RestServlet):
             "user_id": user_id,
             "home_server": self.hs.hostname,
         }
-        if not params.get("inhibit_login", False):
+        # We don't want to log the user in if we're going to deny them access because
+        # they need to be approved first.
+        if not params.get("inhibit_login", False) and not self._require_approval:
             device_id = params.get("device_id")
             initial_display_name = params.get("initial_device_display_name")
             (
-- 
cgit 1.4.1