On Thu, 13 Jul 2017 17:58:29 +0300 Andrew Savchenko wrote:
> 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@iee.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.

One more example: remember the bumblebee install script bug[1]: due
to a typo the whole /usr was removed, the same may happen with /sys
one day.

If simple file removal results in dead hardware this is no go.

[1]
https://github.com/MrMEEE/bumblebee-Old-and-abbandoned/issues/123

Best regards,
Andrew Savchenko