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Re: Emergency Unmount...
On Wed, Apr 04, 2001 at 02:30:26PM +0200, Perego Paolo wrote:
> On Wed, Apr 04, 2001 at 01:30:38PM +0200, Erik Mouw wrote:
> > On Wed, Apr 04, 2001 at 11:55:02AM +0200, Perego Paolo wrote:
> [snip]
> > Hmm, security through obscurity has never been a good idea, and it's
> The point is that root needs a password to put MOD_USE_COUNT to 0 ( echoing
> that in a char dev ) and he needs to re-enter the password the same way, if he
> wants cleanup-module to exit fairly. I would prevent a malicious user puts
> MOD_USE_COUNT to 0 using /dev/kmem and then removing the module.
Common. Overwritre one instruction with the cuntion return through /dev/kmem
and your module won't help.
> I can't figure out what do you means talking about obscurity :)
Such ideas that look secure if you don't know how they work but are easy to
work around once one knows how.
> > (alt-sysrq-u).
> Already done. The point is that go_sync function ( linux/drivers/char/sysrq.c
> ) is not exported as symbol. I can't rip off that code because it referes to
> other symbols not exported by the kernel.
Walk through the super_blocks linked list. It is not exported not exported to
userspace so you have to do some dirty tricks to find out which of the linked
list entries is the head...
Christoph
--
Of course it doesn't work. We've performed a software upgrade.
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