Re: [PATCH 1/3] mm: vmalloc: export __vmalloc_node_range

[Matthew Wilcox]

On Tue, Jul 23, 2024 at 05:00:43PM -0700, Andrew Morton wrote:
> On Fri, 19 Jul 2024 13:42:40 +0100 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> 
> > On Fri, Jul 19, 2024 at 07:58:40AM -0400, Mary Strodl wrote:
> > > Maybe some of the stuff the driver does right now could be moved into
> > > vmalloc? In other words, we could provide a different function that
> > > allocates an executable page, copies memory into it, then marks it
> > > read-only. Would that do better to alleviate concerns?
> > 
> > No.  We are not running arbitrary x86 code.  That is a security
> > nightmare.
> 
> Sure, if such a thing were to be done we'd want it localized within the
> driver rather than offered globally.
> 
> But if there was some hack within the driver to do this, what problems
> might that cause?  What are the scenarios?

That we're running arbitrary x86 code (provided by the manufacturer)
inside the kernel where it can undermine every security guarantee we
provide?