Re: [Fsfe-uk] Linux for Kids Briefi

[Philip Hands]

Dominic Hargreaves wrote:

> Uhm, how is this going to be better? At best it will be no worse than a
> poorly configured pam_console hack, since at least you /might/, with
> said hack, restrict access to the bona fide "owner" of the data on
> removable drives.  If you just put everyone is a group that can read the
> device all the time you have lost completely.

Ah, now you're coming up with a different justification for doing that.

By default, the files on a mounted CD are world readable, so restricting 
who can mount it doesn't get you what you're asking for.  To achieve 
that with pam_console, you'd also have to have it tweak the options in 
/etc/fstab to set the mask and uid settings, which would make it even 
more disgusting in my view (and considerably more complicated, bug prone 
etc.).

I suppose if I wanted to do what you describe I'd write a mount wrapper 
that sets the permissions on the contents using mount's uid/gid/mask 
options, and then use sudo to ensure only the right people are allowed 
to run that script as root.

If you're willing to turn Linux into a single-user system, then 
pam_console fits right in, but I'd say that the fact that it makes the 
system's behaviour variable means that it's likely to make the system 
less reliable, and less predictable.

To make a feeble effort at dragging this back on topic, I'd say that the 
reason that the few children I know seem to have no interest in finding 
out how computers work is that they've been exposed mostly to MS 
systems, which behave somewhat randomly, and therefore give the 
impression of being run by magic, and incomprehensible.

I'd say you've got a much better chance of explaining that a device is 
only accessible because of group permissions, possibly via a script that 
 enables that access, than having to dive into the fact that every time 
you log in some of PAM has rummaged with your system to make it seem 
more friendly than it really is.   I suppose pam_console makes me 
bristle because it gives rise to surprising behaviour.

Let's say that you explain to your child that when they asked you to log 
in to look at something else via ssh, that you broke their access to the 
CD, and that in future if that happens and you're not around, they 
should log out and back in again to fix it.  Does that make the system 
sound like it's likely to be easily understandable, and worth 
investigating further?

On the other hand, if you say "Ah, the reason you were not allowed to do 
that is because you're not a member of the cdrom group, I'll add you to 
that group, and that problem will be solved forever".

If you say that pam_console shouldn't do that for ssh logins, then you 
have to explain to your child why when they ssh between machines that 
they can do everything they can normally do on the machine, oh, except 
mount a CD, etc. etc.

Cheers, Phil.

signature.asc
Description: OpenPGP digital signature