Re: [PATCH v3 36/37] x86/cet/shstk: Add ARCH_CET_UNLOCK

Dave Hansen
2022-11-15T21:01:05Z

On 11/15/22 12:57, Peter Zijlstra wrote:
> On Tue, Nov 15, 2022 at 08:01:12PM +0000, Edgecombe, Rick P wrote:
>>>> + if (task != current) {
>>>> + if (option == ARCH_CET_UNLOCK &&
>>>> IS_ENABLED(CONFIG_CHECKPOINT_RESTORE)) {
>>> Why make this conditional on CRIU at all?
>> Kees asked for it, I think he was worried about attackers using it to
>> unlock and disable shadow stack. So wanted to lock it down to the
>> maximum.
> Well, distros will all have this stuff enabled no? So not much
> protection in practise.

Yeah, that's true for the distros.

But, I would imagine that our more paranoid friends like the ChromeOS
folks might appreciate this.