Re: [PATCH v1 0/2] Add LSM access controls for io_uring_setup

From: Stephen Smalley
Date: Thu Aug 10 2023 - 08:28:11 EST


On Thu, Aug 10, 2023 at 5:08 AM Dmytro Maluka <dmy@xxxxxxxxxxxx> wrote:
>
> On 8/9/23 19:28, Dmytro Maluka wrote:
> > So one of the questions I'm wondering about is: if Android implemented
> > preventing execution of any io_uring code by non-trusted processes
> > (via seccomp or any other way), how much would it help to reduce the
> > risk of attacks, compared to its current SELinux based solution?
>
> And why exactly I'm wondering about that: AFAICT, Android folks are
> concerned about the high likelihood of vulnerabilities in io_uring code
> just like we (ChromeOS folks) are, and that is the main reason why
> Android takes care of restricting io_uring usage in the first place.

I think if you audit the io_uring syscalls and find a code path that
is not already mediated by a LSM hook (potentially at an earlier point
during setup / fd creation) that accesses any shared resource or
performs a privileged action, we would be open to adding a LSM hook to
cover that code path. But you'd have to do the work to identify and
propose such cases.