Re: [gentoo-dev] newsitem: openrc-0.28 mounts efivars read only

[Andrew Savchenko]

On Thu, 13 Jul 2017 10:29:06 -0400 Mike Gilbert wrote:
> On Thu, Jul 13, 2017 at 7:35 AM, M. J. Everitt <m.j.everitt@×××.org> wrote:
> > On 13/07/17 12:09, Rich Freeman wrote:
> >> Presumably you'd only want to remount it if it was mounted ro to
> >> start, since it sounds like openrc will be diverging from systemd
> >> behavior here.
> >>
> >> While it seems like a good idea I'm not sure how big an improvement it
> >> is in the larger scheme.  We're worried about root accidentially
> >> modifying efivars, but we have no safeguards against root writing to
> >> /dev/sda, and the latter seems much more likely to cause harm, and is
> >> harder to fix.
> >>
> > In case you weren't aware, Rich, rewriting the efivars actually writes
> > to the system BIOS, which renders the computer completely unbootable ..
> > not quite the same as erasing the boot sector of your hard disk, where
> > you simply plug in another device, and Off you go ...
> >
>
> We are actually talking about protecting people who run something like
> rm -rf /sys/firmware/efi/efivars/ as root.
>
> If you are dumb enough to do something like that, you almost deserve
> to spend a couple hundred on a new motherboard.
 
Or just rm -rf /
[pedantic]
of course with newer rm versions one needs to run:
rm -rf --no-preserve-root /
or
rm -rf /* /.*
[/pedantic]

But in some scenarios this command is normal. E.g. user installs
Gentoo from some live dvd/flash, makes some mistakes, understands
that system is broken beyond repair and decides to start over again.
If there is no need to recreate filesystem itself or partition
layout, running rm -rf / as above is quite reasonable.

When running this command user expects to kill the data, but not
the hardware. That is my point. I can't call such action dumb.

Best regards,
Andrew Savchenko