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From: Peter Zijlstra <peterz@infradead.org>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH SSBv11 3/3] seccomp 0
Date: Thu, 3 May 2018 10:58:01 +0200	[thread overview]
Message-ID: <20180503085800.GX12217@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: =?utf-8?q?=3C5f6464d53346d3939a81cab15e5d5b20ad90c05d=2E15253?= =?utf-8?q?08267=2Egit=2Ekeescook=40chromium=2Eorg=3E?=

On Tue, May 01, 2018 at 03:07:31PM -0700, speck for Kees Cook wrote:
> @@ -239,6 +254,9 @@ static inline void seccomp_assign_mode(struct task_struct *task,
>  	 */
>  	smp_mb__before_atomic();
>  	set_tsk_thread_flag(task, TIF_SECCOMP);
> +
> +	/* Assume seccomp processes want speculation flaw mitigation. */
> +	spec_mitigate(task, PR_SPEC_STORE_BYPASS);
>  }

What about the ordering there? That function appears to explicitly set
TIF_SECCOMP last, such that when that is observed, the complete
environment is observed.

But now you add something after it. Does this not mean that if you set
this on a remote task, this task can execute TIF_SECCOMP thing before it
disables SSB.

Is that OK?

  parent reply	other threads:[~2018-05-03  8:58 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-03  0:44 [MODERATED] [PATCH SSBv11 0/3] seccomp 1 Kees Cook
2018-05-01 22:07 ` [MODERATED] [PATCH SSBv11 3/3] seccomp 0 Kees Cook
2018-05-01 22:19 ` [MODERATED] [PATCH SSBv11 1/3] seccomp 2 Kees Cook
2018-05-01 22:31 ` [MODERATED] [PATCH SSBv11 2/3] seccomp 3 Kees Cook
2018-05-03  8:58 ` Peter Zijlstra [this message]
2018-05-03  9:21   ` [PATCH SSBv11 3/3] seccomp 0 Thomas Gleixner
2018-05-03 16:03     ` [MODERATED] " Kees Cook
2018-05-03 12:29 ` [MODERATED] Re: [PATCH SSBv11 0/3] seccomp 1 Andi Kleen
2018-05-03 12:45   ` Thomas Gleixner
2018-05-03 14:09     ` [MODERATED] " Ingo Molnar
2018-05-03 14:57       ` Andi Kleen
2018-05-03 17:04       ` Kees Cook
2018-05-03 18:58         ` Andi Kleen
2018-05-03 23:17           ` Kees Cook
2018-05-03 14:47     ` Andi Kleen

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