If you don't want the web installer to be able to write the config file at all, it is also possible to make the config file read-only for the gitea user (owner/group `root:root`, mode `0660`), and set `INSTALL_LOCK = true`. In that case all database configuration details must be set beforehand in the config file, as well as the `SECRET_KEY` and `INTERNAL_TOKEN` values. See the [command line documentation]({{< relref "doc/usage/command-line.en-us.md" >}}) for information on using `gitea generate secret INTERNAL_TOKEN`.
If you don't want the web installer to be able to write the config file at all, it is also possible to make the config file read-only for the gitea user (owner/group `root:git`, mode `0640`), and set `INSTALL_LOCK = true`. In that case all database configuration details must be set beforehand in the config file, as well as the `SECRET_KEY` and `INTERNAL_TOKEN` values. See the [command line documentation]({{< relref "doc/usage/command-line.en-us.md" >}}) for information on using `gitea generate secret INTERNAL_TOKEN`.