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authorGustavo A. R. Silva <gustavo@embeddedor.com>2019-03-20 16:15:24 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-03 06:24:16 +0200
commitc84a7647520fdf933d978d0202bc2d67374756ff (patch)
tree8ad8c58529619be069478781fef8bc021c79231c /sound
parentc9416ce92003b7dc48671af2654abffc2250ecd6 (diff)
ALSA: rawmidi: Fix potential Spectre v1 vulnerability
commit 2b1d9c8f87235f593826b9cf46ec10247741fff9 upstream. 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@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound')
-rw-r--r--sound/core/rawmidi.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 59111cadaec2..c8b2309352d7 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -29,6 +29,7 @@
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/delay.h>
+#include <linux/nospec.h>
#include <sound/rawmidi.h>
#include <sound/info.h>
#include <sound/control.h>
@@ -591,6 +592,7 @@ static int __snd_rawmidi_info_select(struct snd_card *card,
return -ENXIO;
if (info->stream < 0 || info->stream > 1)
return -EINVAL;
+ info->stream = array_index_nospec(info->stream, 2);
pstr = &rmidi->streams[info->stream];
if (pstr->substream_count == 0)
return -ENOENT;