Hash passwords earlier in the password reset process (#7538)

This now matches the logic of the registration process as modified in
56db0b1365965c02ff539193e26c333b7f70d101 / #7523.

1 files changed, 18 insertions, 3 deletions

diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 1bd0234779..d4f721b6b9 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -220,12 +220,27 @@ class PasswordRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.auth_handler = hs.get_auth_handler()
         self.datastore = self.hs.get_datastore()
+        self.password_policy_handler = hs.get_password_policy_handler()
         self._set_password_handler = hs.get_set_password_handler()
 
     @interactive_auth_handler
     async def on_POST(self, request):
         body = parse_json_object_from_request(request)
 
+        # we do basic sanity checks here because the auth layer will store these
+        # in sessions. Pull out the new password provided to us.
+        if "new_password" in body:
+            new_password = body.pop("new_password")
+            if not isinstance(new_password, str) or len(new_password) > 512:
+                raise SynapseError(400, "Invalid password")
+            self.password_policy_handler.validate_password(new_password)
+
+            # If the password is valid, hash it and store it back on the body.
+            # This ensures that only the hashed password is handled everywhere.
+            if "new_password_hash" in body:
+                raise SynapseError(400, "Unexpected property: new_password_hash")
+            body["new_password_hash"] = await self.auth_handler.hash(new_password)
+
         # there are two possibilities here. Either the user does not have an
         # access token, and needs to do a password reset; or they have one and
         # need to validate their identity.
@@ -276,12 +291,12 @@ class PasswordRestServlet(RestServlet):
                 logger.error("Auth succeeded but no known type! %r", result.keys())
                 raise SynapseError(500, "", Codes.UNKNOWN)
 
-        assert_params_in_dict(params, ["new_password"])
-        new_password = params["new_password"]
+        assert_params_in_dict(params, ["new_password_hash"])
+        new_password_hash = params["new_password_hash"]
         logout_devices = params.get("logout_devices", True)
 
         await self._set_password_handler.set_password(
-            user_id, new_password, logout_devices, requester
+            user_id, new_password_hash, logout_devices, requester
         )
 
         return 200, {}