linux-kernel - Re: [PATCH v3 36/37] x86/cet/shstk: Add ARCH_CET

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Message-ID: <Y3P9V1c0ytuC2/3g@hirez.programming.kicks-ass.net>
Date:   Tue, 15 Nov 2022 21:57:59 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
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Subject: Re: [PATCH v3 36/37] x86/cet/shstk: Add ARCH_CET_UNLOCK

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.