Am Donnerstag, 12. November 2009 schrieb Michael Meskes:
> On Fri, Nov 06, 2009 at 08:06:33PM +0100, Wolfgang Walter wrote:
> > 2) It therefor runs as root. And it even does if /lib/modules/<installed
> > kernel>/source points to a non privileged build directory which is a
> > security problem.
>
> I don't really see where the security problem is here. Would you mind
> explaining it?
>
Say you built your kernel as user foo on one machine.
Say
/lib/modules/2.6.31.6/source
or
/lib/modules/2.6.31.6/build
therefor may points to
/home/foo/kernels/linux-2.6.31.6
Now you install that kernel on a different machine "exposed" where user foo
exists, too.
You now have to trust machine "exposed". You must trust f...@exposed that it
does not provide a manipulated /home/foo/kernels/linux-2.6.31.6 which will
either produce a trojaned kernel module or simply uses errors in dkms, gcc,
binutils, ... to gain root access.
I think virtualbox should do it like other similar packages which build kernel
modules:
virtualbox-ose-source for building binary-modules as self-sufficent
deb-packages
virtualbox-ose-dkms for the dkms approach
Sehe batman-adv-source|dkms or openafs-modules-source|dkms
Regards,
--
Wolfgang Walter
Studentenwerk München
Anstalt des öffentlichen Rechts
Leiter EDV
Leopoldstraße 15
80802 München
Tel: +49 89 38196 276
Fax: +49 89 38196 150
Email: [email protected]
http://www.studentenwerk-muenchen.de/
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