How to run atmoz/sftp with rootless podman (quadlets) + systemd socket activation + Network=none?

[eriksjolund]

Does anyone know how to run atmoz/sftp with rootless podman (quadlets) and systemd socket activation?

It would be cool to use

Network=none

because sshd would then not have the privileges to connect to the internet. This improves security.
If sshd would be compromised, the intruder would not be able to use the server as a spam bot.

Docker does not support socket activation of containers so we currently need to use quadlets for this.

Side note:
I did a proof-of-concept (openssh with socket activation support from a git branch I found on the internet)
https://github.com/eriksjolund/podman-openssh-socket-activation
It seems to work.

After that I tried out atmoz/sftp (the debian version) but it failed. Then I tried building atomz/sftp with ubuntu as base image.
Building the image succeeded but when the sshd service is started, sshd prints the error message

Failed to get systemd socket fds: Numerical result out of range

Some more details are found here:
eriksjolund/podman-openssh-socket-activation#3 (comment)