Re: immutable flag on ext2fs

Alan Cox (alan@lxorguk.ukuu.org.uk)
Mon, 21 Jun 1999 22:39:46 +0100 (BST)


> > There is a proper way to solve this. Use 2.0.37 and redefine the securelevel
> > to read from a parallel port or similar and check for a magic code. Now you
> > can wire yourself a superuser enable dongle .
>
> Care to elaborate on this a bit?

On a PC the lp data port is a single readable register normally living
on a side bus of the PCI chipset (so fast). Just read it and check it
is some specific magic value.

> adapter to do a smartcard/dongle kind of thing for some crypto work. For
> a laptop, this helps keep things like keys off the box and transportable
> Sounds like a similar idea to the parallel port idea.

Very, although its harder to check instantly in kernel. I guess you'd have
to put in code that allows key based changing of securelevel via an ioctl

> What about 2.2? I noticed that the capabilities stuff is largely
> supplanting the securelevel idea.

They are simply more fine grained. Chris Evans has found a couple of problems
with the current model but they are fixable

Alan

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