Hash passwords earlier in the registration process (#7523)

changelog.d/7523.bugfix

@@ -0,0 +1 @@
+Hash passwords as early as possible during registration.

synapse/handlers/register.py

@@ -132,7 +132,7 @@ class RegistrationHandler(BaseHandler):
     def register_user(
         self,
         localpart=None,
-        password=None,
+        password_hash=None,
         guest_access_token=None,
         make_guest=False,
         admin=False,
@@ -147,7 +147,7 @@ class RegistrationHandler(BaseHandler):
         Args:
             localpart: The local part of the user ID to register. If None,
               one will be generated.
-            password (unicode): The password to assign to this user so they can
+            password_hash (str|None): The hashed password to assign to this user so they can
               login again. This can be None which means they cannot login again
               via a password (e.g. the user is an application service user).
             user_type (str|None): type of user. One of the values from
@@ -164,11 +164,6 @@ class RegistrationHandler(BaseHandler):
         yield self.check_registration_ratelimit(address)
 
         yield self.auth.check_auth_blocking(threepid=threepid)
-        password_hash = None
-        if password:
-            password_hash = yield defer.ensureDeferred(
-                self._auth_handler.hash(password)
-            )
 
         if localpart is not None:
             yield self.check_username(localpart, guest_access_token=guest_access_token)

synapse/rest/admin/users.py

@@ -243,11 +243,11 @@ class UserRestServletV2(RestServlet):
 
         else:  # create user
             password = body.get("password")
-            if password is not None and (
-                not isinstance(body["password"], text_type)
-                or len(body["password"]) > 512
-            ):
-                raise SynapseError(400, "Invalid password")
+            password_hash = None
+            if password is not None:
+                if not isinstance(password, text_type) or len(password) > 512:
+                    raise SynapseError(400, "Invalid password")
+                password_hash = await self.auth_handler.hash(password)
 
             admin = body.get("admin", None)
             user_type = body.get("user_type", None)
@@ -259,7 +259,7 @@ class UserRestServletV2(RestServlet):
 
             user_id = await self.registration_handler.register_user(
                 localpart=target_user.localpart,
-                password=password,
+                password_hash=password_hash,
                 admin=bool(admin),
                 default_display_name=displayname,
                 user_type=user_type,
@@ -298,7 +298,7 @@ class UserRegisterServlet(RestServlet):
     NONCE_TIMEOUT = 60
 
     def __init__(self, hs):
-        self.handlers = hs.get_handlers()
+        self.auth_handler = hs.get_auth_handler()
         self.reactor = hs.get_reactor()
         self.nonces = {}
         self.hs = hs
@@ -362,16 +362,16 @@ class UserRegisterServlet(RestServlet):
                 400, "password must be specified", errcode=Codes.BAD_JSON
             )
         else:
-            if (
-                not isinstance(body["password"], text_type)
-                or len(body["password"]) > 512
-            ):
+            password = body["password"]
+            if not isinstance(password, text_type) or len(password) > 512:
                 raise SynapseError(400, "Invalid password")
 
-            password = body["password"].encode("utf-8")
-            if b"\x00" in password:
+            password_bytes = password.encode("utf-8")
+            if b"\x00" in password_bytes:
                 raise SynapseError(400, "Invalid password")
 
+            password_hash = await self.auth_handler.hash(password)
+
         admin = body.get("admin", None)
         user_type = body.get("user_type", None)
 
@@ -388,7 +388,7 @@ class UserRegisterServlet(RestServlet):
         want_mac_builder.update(b"\x00")
         want_mac_builder.update(username)
         want_mac_builder.update(b"\x00")
-        want_mac_builder.update(password)
+        want_mac_builder.update(password_bytes)
         want_mac_builder.update(b"\x00")
         want_mac_builder.update(b"admin" if admin else b"notadmin")
         if user_type:
@@ -407,7 +407,7 @@ class UserRegisterServlet(RestServlet):
 
         user_id = await register.registration_handler.register_user(
             localpart=body["username"].lower(),
-            password=body["password"],
+            password_hash=password_hash,
             admin=bool(admin),
             user_type=user_type,
         )

synapse/rest/client/v2_alpha/register.py

@@ -426,12 +426,16 @@ class RegisterRestServlet(RestServlet):
         # we do basic sanity checks here because the auth layer will store these
         # in sessions. Pull out the username/password provided to us.
         if "password" in body:
-            if (
-                not isinstance(body["password"], string_types)
-                or len(body["password"]) > 512
-            ):
+            password = body.pop("password")
+            if not isinstance(password, string_types) or len(password) > 512:
                 raise SynapseError(400, "Invalid password")
-            self.password_policy_handler.validate_password(body["password"])
+            self.password_policy_handler.validate_password(password)
+
+            # If the password is valid, hash it and store it back on the request.
+            # This ensures the hashed password is handled everywhere.
+            if "password_hash" in body:
+                raise SynapseError(400, "Unexpected property: password_hash")
+            body["password_hash"] = await self.auth_handler.hash(password)
 
         desired_username = None
         if "username" in body:
@@ -484,7 +488,7 @@ class RegisterRestServlet(RestServlet):
 
         guest_access_token = body.get("guest_access_token", None)
 
-        if "initial_device_display_name" in body and "password" not in body:
+        if "initial_device_display_name" in body and "password_hash" not in body:
             # ignore 'initial_device_display_name' if sent without
             # a password to work around a client bug where it sent
             # the 'initial_device_display_name' param alone, wiping out
@@ -546,11 +550,11 @@ class RegisterRestServlet(RestServlet):
             registered = False
         else:
             # NB: This may be from the auth handler and NOT from the POST
-            assert_params_in_dict(params, ["password"])
+            assert_params_in_dict(params, ["password_hash"])
 
             desired_username = params.get("username", None)
             guest_access_token = params.get("guest_access_token", None)
-            new_password = params.get("password", None)
+            new_password_hash = params.get("password_hash", None)
 
             if desired_username is not None:
                 desired_username = desired_username.lower()
@@ -583,7 +587,7 @@ class RegisterRestServlet(RestServlet):
 
             registered_user_id = await self.registration_handler.register_user(
                 localpart=desired_username,
-                password=new_password,
+                password_hash=new_password_hash,
                 guest_access_token=guest_access_token,
                 threepid=threepid,
                 address=client_addr,