Commit f526afcd authored Apr 24, 2018 by Takashi Iwai

ALSA: rme9652: Hardening for potential Spectre v1

As recently Smatch suggested, one place in RME9652 driver may expand
the array directly from the user-space value with speculation:
sound/pci/rme9652/rme9652.c:2074 snd_rme9652_channel_info() warn: potential spectre issue 'rme9652->channel_map' (local cap)

This patch puts array_index_nospec() for hardening against it.

BugLink: https://marc.info/?l=linux-kernel&m=152411496503418&w=2

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent 10513142

sound/pci/rme9652/rme9652.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -26,6 +26,7 @@
		#include <linux/pci.h>
		#include <linux/module.h>
		#include <linux/io.h>
		#include <linux/nospec.h>

		#include <sound/core.h>
		#include <sound/control.h>
		@@ -2071,9 +2072,10 @@ static int snd_rme9652_channel_info(struct snd_pcm_substream *substream,
		if (snd_BUG_ON(info->channel >= RME9652_NCHANNELS))
		return -EINVAL;

		if ((chn = rme9652->channel_map[info->channel]) < 0) {
		chn = rme9652->channel_map[array_index_nospec(info->channel,
		RME9652_NCHANNELS)];
		if (chn < 0)
		return -EINVAL;
		}

		info->offset = chn * RME9652_CHANNEL_BUFFER_BYTES;
		info->first = 0;