Re: [PATCH] ALSA: isa/wavefront: Fix potential Spectre v1 vulnerabilities

[Gustavo A. R. Silva]

On 12/20/18 2:11 AM, Takashi Iwai wrote:
> On Thu, 20 Dec 2018 00:31:43 +0100,
>   Gustavo A. R. Silva  wrote:
> > header->number is indirectly controlled by user-space, hence leading
> > to a potential exploitation of the Spectre variant 1 vulnerability.
> >
> > This issue was detected with the help of Smatch:
> >
> > sound/isa/wavefront/wavefront_synth.c:792 wavefront_send_patch() warn: potential spectre issue 'dev->patch_status' [w] (local cap)
> > sound/isa/wavefront/wavefront_synth.c:819 wavefront_send_program() warn: potential spectre issue 'dev->prog_status' [w] (local cap)
> > sound/isa/wavefront/wavefront_synth.c:1197 wavefront_send_alias() warn: potential spectre issue 'dev->sample_status' [w]
> > sound/isa/wavefront/wavefront_synth.c:1248 wavefront_send_multisample() warn: potential spectre issue 'dev->sample_status' [w]
> > sound/isa/wavefront/wavefront_synth.c:1548 wavefront_synth_control() warn: potential spectre issue 'dev->sample_status' [r] (local cap)
> >
> > Fix this by sanitizing header->number before using it to index
> > dev->patch_status, dev->prog_status and dev->sample_status.
> >
> > Notice that given that speculation windows are large, the policy is
> > to kill the speculation on the first load and not worry if it can be
> > completed with a dependent load/store [1].
> >
> > [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
>
> Is there any platform with ISA slot that suffers from Spectre?

Do you mean 'any other'?

If so, yeah, I just spotted some Spectre vulns in sound/isa/sb/emu8000.c

I'll send a patch for that.

Thanks
--
Gustavo