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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2019-03-20 16:15:24 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-03 06:26:22 +0200 |
commit | bd55e6727a33b89d5575e2759eef82ad9551a45c (patch) | |
tree | c1e5a84ee1d82882159e0c4c12a42029d5a6eb0e | |
parent | a485919fe4cc18d72bd0bae8e11fdcaf75b378f0 (diff) | |
download | linux-stable-bd55e6727a33b89d5575e2759eef82ad9551a45c.tar.gz linux-stable-bd55e6727a33b89d5575e2759eef82ad9551a45c.tar.bz2 linux-stable-bd55e6727a33b89d5575e2759eef82ad9551a45c.zip |
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>
-rw-r--r-- | sound/core/rawmidi.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c index 08d5662039e3..a52d6d16efc4 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; |