[Cialug] Secure Linux System

[Josh More]

Ken beat me to it.

I've built read-only Linux-based kiosk machines twice.  After both
experiences, I decided that that was the wrong solution to the
problem.  I hope I don't have to learn it again.  ;)

The fundamental problem is that while user-tampering is an annoyance
that read-only is well-designed to solved, web-based systems face far
more serious threats that read-only systems prevent you from solving.
To fight against malicious sites, for example, modern browsers store
local blacklist files that they download before launch. Usually they
just download deltas, so it's not a huge delay.  On a read-only
system, they have to download the delta from gold, which could grow
very large very quickly.

In many cases, it makes more sense to have a read-write system that
reloads profiles at boot, so system updates can still be applied.  For
browser-only systems, you could do a bit of fstab and firefox profile
scripting to get the best of both worlds.  (Probably possible in
Chrome too, but their update cycle is a bit weirder.)

For the true tinkerers, you could always boot into Xen, run a minimal
X in Xen (a general no no, but that can be worked around) that
auto-launches a VNC session into one of the Xen VMs that resets from
gold at boot and mounts as read-only + ram disk each time.  Not a good
design in most cases, but I can think of some situations where it
beats all others.

-Josh More



On Tue, Sep 11, 2012 at 9:28 PM, kristau <kristau at gmail.com> wrote:
> On Tue, Sep 11, 2012 at 8:50 PM, L. V. Lammert <lvl at omnitec.net> wrote:
>> Just need a browser, basically. Not sure how LTS would apply? Knoppix
>> would be pretty much overkill.
>>
>> Thinking of something like PuppyLinux, .. but the main problem is how to
>> add things like printer drivers.
>>
>>         Lee
>
> Well, you don't *just* need a browser. It sounds like you need
> printing too? If you just needed a browser, any live bootable distro
> would work just fine.
>
> Why do you need to print (do you really need dead tree versions)? How
> often would you need to reset the system? How many printers? What
> brands/models?
>
> Ubuntu Live might work if you don't mind re-configuring CUPS each time
> you reset. If the printers don't change much, you could probably
> script the commands to add them, too. That would save time after a
> reset.
>
> Taking a big step back, what is your use case and requirements? You
> started by presenting us with a solution (build a read only linux).
> Instead, give us your problem/situation and we may come up with
> alternative solutions.
>
> --
> Tired programmer
> Coding late into the night
> The core dump follows
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