Re: Modprobe local root exploit

From: Jakub Jelinek (jakub@redhat.com)
Date: Tue Nov 14 2000 - 05:54:10 EST


On Tue, Nov 14, 2000 at 10:42:41AM +0000, Malcolm Beattie wrote:
> Keith Owens writes:
> > All these patches against request_module are attacking the problem at
> > the wrong point. The kernel can request any module name it likes,
> > using any string it likes, as long as the kernel generates the name.
> > The real problem is when the kernel blindly accepts some user input and
> > passes it straight to modprobe, then the kernel is acting like a setuid
> > wrapper for a program that was never designed to run setuid.
>
> Rather than add sanity checking to modprobe, it would be a lot easier
> and safer from a security audit point of view to have the kernel call
> /sbin/kmodprobe instead of /sbin/modprobe. Then kmodprobe can sanitise
> all the data and exec the real modprobe. That way the only thing that
> needs auditing is a string munging/sanitising program.

Well, no matter what kernel needs auditing as well, the fact that dev_load
will without any check load any module the user wants is already problematic
and no munging helps with it at all, especially loading old ISA drivers
might not be a good idea.

        Jakub
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Wed Nov 15 2000 - 21:00:25 EST