Re: [PATCH v3 1/3] ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks

Jiri Kosina
2018-09-05T18:35:24Z

On Wed, 5 Sep 2018, Andi Kleen wrote:

> Please if you repost include plenty of performance numbers for multi
> threaded workloads. It's ridiculous to even discuss this without them.

Talking about ridiculous ... I find it a bit sad that Intel has let this
be unfixed for 3/4 years in linux; that doesn't really signal deep
dedication to customer safety. Have any STIBP patches been even submitted?

This is not the same situation as IBRS which was mostly ignored -- there
we have retpolines to protect the kernel, and it's debatable whether it's
exploitable on SKL at all.

Ignoring IBPB and STIBP is keeping the system plain vulnerable to
user-user attacks, and us not providing users with possibiliy to easily
mitigate, is a bit embarassing in my eyes.

Thanks,

--
Jiri Kosina
SUSE Labs