Re: [PATCH] libahci: Fix possible Spectre-v1 pmp indexing in ahci_led_store()

From: Tejun Heo
Date: Mon Jun 18 2018 - 14:05:07 EST


On Fri, Jun 08, 2018 at 06:26:33PM +0800, John Garry wrote:
> Currently smatch warns of possible Spectre-V1 issue in ahci_led_store():
> drivers/ata/libahci.c:1150 ahci_led_store() warn: potential spectre issue 'pp->em_priv' (local cap)
>
> Userspace controls @pmp from following callchain:
> em_message->store()
> ->ata_scsi_em_message_store()
> -->ap->ops->em_store()
> --->ahci_led_store()
>
> After the mask+shift @pmp is effectively an 8b value, which is used to
> index into an array of length 8, so sanitize the array index.
>
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>

Applied to libata/for-4.18-fixes.

Thanks.

--
tejun