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Re: A question about Knark and modules



On Mon, Jun 18, 2001 at 08:56:03AM +0200, Philipp Schulte wrote:
> On Sun, Jun 17, 2001 at 10:42:17PM -0800, Ethan Benson wrote: 
> 
> > you would need to fix filesystem immutability and block device access
> > as well.   currently lcap CAP_LINUX_IMMUTABLE is useless since there
> > is no way to deny root the ability to write directly to /dev/hda* and
> > remove the immutable bits (ive written a script to remove chattr +i
> > and +a even when CAP_LINUX_IMMUTABLE is removed from the bounding set,
> > no reboot required). 
> 
> I thought CAP_SYS_RAWIO would take care of that issue?
> Is is still possible to chattr +i if CAP_SYS_RAWIO is removed?

chattr +i and +a cannot be set or removed if CAP_LINUX_IMMUTABLE is
removed from the bounding set.  however that does not prevent root
from messing with /dev/hda* directly, niether does CAP_SYS_RAWIO.  

there is no capability that allows you to deny root access to the raw
block devices, so removing the immutable bit is trivially easy. 

-- 
Ethan Benson
http://www.alaska.net/~erbenson/

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