Re: PCI arbiter memory mapping

[Sergey Bugaev]

On Wed, Aug 18, 2021 at 8:43 PM Joan Lledó <jlledom@mailfence.com> wrote:
> El 18/8/21 a les 0:02, Sergey Bugaev ha escrit:
> > To me it sounds like libpciaccess should have a Hurd-specific API
> > addition that would let the user get the memory object
>
> That's a solution and can be done. But I'd like to know more about
> vm_region first. It seems it can return the object, and I don't see why
> is a security problem to allow a task to retrieve objects belonging to
> itself.

Basically because it allowed the task to overcome any limitations
imposed onto it by max_protection (and offset/size). If you have page
2 of a memory object mapped into your address space read-only, that
shouldn't let you write to page 5.

Sergey