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

Sakari Ailus
2020-04-17T13:38:26Z

On Fri, Apr 17, 2020 at 03:14:24PM +0200, Peter Zijlstra wrote:
> On Fri, Apr 17, 2020 at 03:57:35PM +0300, Sakari Ailus wrote:
> > Hi Christoph,
> >
> > 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.
> >
> > It's not very polite to suggest breaking other people's drivers for such a
> > small matter, staging or not. That'd be bound to break kernel compilation
> > for a lot of people, if for nothing else.
> >
> > Anyway, thanks for cc'ing me. I agree with suggestion and I'll submit a
> > patch to address it.
>
> Already done, see:
>
> https://lkml.kernel.org/r/20200414131348.444715-5-hch@lst.de

Ah, thanks for pointing this out. Please ignore this then.

--
Regards,

Sakari Ailus