Re: [PATCH] mm/vmalloc: Sanitize __get_vm_area() arguments

Peter Zijlstra
2020-04-06T14:06:40Z

On Mon, Apr 06, 2020 at 06:01:55AM -0700, Christoph Hellwig wrote:
> On Fri, Apr 03, 2020 at 06:32:53PM +0200, Peter Zijlstra wrote:
> >
> > __get_vm_area() is an exported symbol, make sure the callers stay in
> > the expected memory range. When calling this function with memory
> > ranges outside of the VMALLOC range *bad* things can happen.
> >
> > (I noticed this when I managed to corrupt the kernel text by accident)
>
> Maybe it is time to unexport it? There are only two users:
>
> - staging/media/ipu3 really should be using vmap. And given that it
> is a staging driver it really doesn't matter anyway if we break it.
> - pcmcia/electra_cf.c is actually using it for something that is not
> a vmalloc address. But it is so special that I think prohibiting
> to build it as module seems fine.

I think I just sent you a patch along those lines ;-)