install --ondev: run setup_login for installer OS
Run setup_login() while creating the installer OS too, in order to disable passwordless root login.
Note that this may sound like a security flaw, but it isn't.
- setup_login already ran for the target OS, meaning after the installation is done, one is not be able to login as root without password
- root login without password was only possible via serial console (or by attaching a keyboard), not via SSH
- getting root rights via serial in the installer OS is actually desired for debugging, we add a debug user with sudo set up by default: https://wiki.postmarketos.org/wiki/On-device_installer#Debug_user
So even though this isn't a problem, disable it to avoid confusion.
Test plan
- Run the on-device installer in QEMU
- Without this patch, you can login as root without password in the login prompt shown in
pmbootstrap qemu
- With the patch you can't login as root