path: root/sound
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authorGustavo A. R. Silva <gustavo@embeddedor.com>2019-03-20 16:15:24 -0500
committerTakashi Iwai <tiwai@suse.de>2019-03-21 13:21:15 +0100
commit2b1d9c8f87235f593826b9cf46ec10247741fff9 (patch)
treec592769a24939ce800b7038fa4faba8908679506 /sound
parent667a8f73753908c4d0171e52b71774f9be5d6713 (diff)
ALSA: rawmidi: Fix potential Spectre v1 vulnerability
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>
Diffstat (limited to 'sound')
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index ee601d7f0926..c0690d1ecd55 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -30,6 +30,7 @@
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/mm.h>
+#include <linux/nospec.h>
#include <sound/rawmidi.h>
#include <sound/info.h>
#include <sound/control.h>
@@ -601,6 +602,7 @@ 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;