add tool for network user's sub{uid,gid} (apptainer --fakeroot like option for podman)

[Ethan-arrr]

Feature request description

Network authenticated users with active directory cant use podman unless they are added to /etc/sub{uid,gid}

apptainer has a nice tool for this called "apptainer config fakeroot --add $x" to add the appropriate users to the subuid and subgid files. I'd love to see a tool from podman that accomplishes this task so we dont have to manually add the users to the subuid and subgid files.

Suggest potential solution

No response

Have you considered any alternatives?

installing appatainer for the tool to add users to the appropriate files works great and then using podman.
another way is to just manually add each users "$UID:4294836224:65536" to /etc/sub{uid,gid}

Additional context

Add any other context or screenshots about the feature request here.

[Luap99]

These files are now owned by podman so it is not really our task to populate them.

The file can be populated with usermod

https://docs.podman.io/en/latest/markdown/podman.1.html#rootless-mode

another way is to just manually add each users "$UID:4294836224:65536" to /etc/sub{uid,gid}

Note you really should give each user a unique range, if you give them the same or overlapping ranges they no have proper uid separation so that can be abused.

[Luap99]

And of course the subuid code actually does have support to source these via the network, i.e. it is implemented in freeipa for AFAIK https://freeipa.readthedocs.io/en/latest/designs/subordinate-ids.html