Re: [RFC][PATCH] Prevent overriding of Symbols in the Kernel, avoiding Undefined behaviour

[Jesper Juhl <jesper.juhl@gmail.com>]

On 12/12/05, Greg KH <greg@kroah.com> wrote:
> On Mon, Dec 12, 2005 at 11:27:46AM -0800, Richard Henderson wrote:
> > On Mon, Dec 12, 2005 at 11:13:22AM -0800, Andrew Morton wrote:
> > > Do we really need to do this at runtime?
> >
> > Probably.  One could consider this a security hole...
>
> Huh?  You are root and loading a kernel module.  You can do much worse
> things at this point in time than messing around with existing symbols
> :)
>
Sure, but having  insmod <foo>  crash the kernel is bad.

In my oppinion the kernel should be robust against accidental loading
of the wrong module. If the symbols of the module clashes with
in-kernel symbols, the logical thing is to reject the module load.

Sure you can do a lot worse things as root, but being able to cause a
crash with a standard tool such as insmod is pretty nasty and
something you can easily get into by accident.  You can't prevent root
from purposely screwing with the kernel, but accidental mis-loading of
a wrong module shouldn't cause a crash.


> I think it should be a build-time thing if possible.
>
If there's a way to revent it 100% at build time I'd agree, but if not
I'd say a runtime solution is required.

Just my 0.02 euro.


--
Jesper Juhl <jesper.juhl@gmail.com>
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