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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-12-12 15:36:28 -0600
committerTakashi Iwai <tiwai@suse.de>2018-12-13 09:14:33 +0100
commit94ffb030b6d31ec840bb811be455dd2e26a4f43e (patch)
treede66c4b427f2f361df27e5cd5f0a84fd2ae41070 /sound/core/pcm.c
parent4aea96f4237cea0c51a8bc87c0db31f0f932f1f0 (diff)
downloadlinux-94ffb030b6d31ec840bb811be455dd2e26a4f43e.tar.bz2
ALSA: pcm: Fix potential Spectre v1 vulnerability
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/pcm.c:140 snd_pcm_control_ioctl() warn: potential spectre issue 'pcm->streams' [r] (local cap) Fix this by sanitizing stream before using it to index pcm->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://marc.info/?l=linux-kernel&m=152449131114778&w=2 Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/pcm.c')
-rw-r--r--sound/core/pcm.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index fdb9b92fc8d6..01b9d62eef14 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -25,6 +25,7 @@
#include <linux/time.h>
#include <linux/mutex.h>
#include <linux/device.h>
+#include <linux/nospec.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/pcm.h>
@@ -129,6 +130,7 @@ static int snd_pcm_control_ioctl(struct snd_card *card,
return -EFAULT;
if (stream < 0 || stream > 1)
return -EINVAL;
+ stream = array_index_nospec(stream, 2);
if (get_user(subdevice, &info->subdevice))
return -EFAULT;
mutex_lock(&register_mutex);