application: verify upload filename

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

moonraker/components/application.py

@@ -980,10 +980,7 @@ class FileUploadHandler(AuthorizedRequestHandler):
     async def post(self) -> None:
         if self.parse_failed:
             self._file.on_finish()
-            try:
-                os.remove(self._file.filename)
-            except Exception:
-                pass
+            self._remove_temp_file()
             raise tornado.web.HTTPError(500, "File Upload Parsing Failed")
         form_args = {}
         chk_target = self._targets.pop('checksum')
@@ -992,20 +989,20 @@ class FileUploadHandler(AuthorizedRequestHandler):
             # Validate checksum
             recd_cksum = chk_target.value.decode().lower()
             if calc_chksum != recd_cksum:
-                # remove temporary file
-                try:
-                    os.remove(self._file.filename)
-                except Exception:
-                    pass
+                self._remove_temp_file()
                 raise tornado.web.HTTPError(
                     422,
                     f"File checksum mismatch: expected {recd_cksum}, "
                     f"calculated {calc_chksum}"
                 )
+        mp_fname: Optional[str] = self._file.multipart_filename
+        if mp_fname is None or not mp_fname.strip():
+            self._remove_temp_file()
+            raise tornado.web.HTTPError(400, "Multipart filename omitted")
         for name, target in self._targets.items():
             if target.value:
                 form_args[name] = target.value.decode()
-        form_args['filename'] = self._file.multipart_filename
+        form_args['filename'] = mp_fname
         form_args['tmp_file_path'] = self._file.filename
         debug_msg = "\nFile Upload Arguments:"
         for name, value in form_args.items():
@@ -1013,7 +1010,7 @@ class FileUploadHandler(AuthorizedRequestHandler):
         debug_msg += f"\nChecksum: {calc_chksum}"
         form_args["current_user"] = self.current_user
         logging.debug(debug_msg)
-        logging.info(f"Processing Uploaded File: {self._file.multipart_filename}")
+        logging.info(f"Processing Uploaded File: {mp_fname}")
         try:
             result = await self.file_manager.finalize_upload(form_args)
         except ServerError as e:
@@ -1041,6 +1038,12 @@ class FileUploadHandler(AuthorizedRequestHandler):
         self.set_header("Content-Type", "application/json; charset=UTF-8")
         self.finish(jsonw.dumps(result))
 
+    def _remove_temp_file(self) -> None:
+        try:
+            os.remove(self._file.filename)
+        except Exception:
+            pass
+
 # Default Handler for unregistered endpoints
 class AuthorizedErrorHandler(AuthorizedRequestHandler):
     async def prepare(self) -> None: