[alsa-devel] [PATCH] ALSA: rawmidi: Fix potential Spectre v1 vulnerability

[Takashi Iwai]

On Wed, 20 Mar 2019 22:15:24 +0100,
 Gustavo A. R. Silva  wrote:
> 
> info->stream 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/core/rawmidi.c:604 __snd_rawmidi_info_select() warn: potential spectre issue 'rmidi->streams' [r] (local cap)
> 
> Fix this by sanitizing info->stream before using it to index
> rmidi->streams.
> 
> 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://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/
> 
> Cc: stable at vger.kernel.org
> Signed-off-by: Gustavo A. R. Silva <gustavo at embeddedor.com>

Applied, thanks.


Takashi