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authorGustavo A. R. Silva <gustavo@embeddedor.com>2019-03-20 18:42:01 -0500
committerTakashi Iwai <tiwai@suse.de>2019-03-21 13:23:51 +0100
commitc709f14f0616482b67f9fbcb965e1493a03ff30b (patch)
tree2cfa6b64ad0a88d95aea65c6c2d13fdb8face6da /sound
parent2b1d9c8f87235f593826b9cf46ec10247741fff9 (diff)
downloadlinux-stericsson-c709f14f0616482b67f9fbcb965e1493a03ff30b.tar.gz
ALSA: seq: oss: Fix Spectre v1 vulnerability
dev 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/seq/oss/seq_oss_synth.c:626 snd_seq_oss_synth_make_info() warn: potential spectre issue 'dp->synths' [w] (local cap) Fix this by sanitizing dev before using it to index dp->synths. 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')
-rw-r--r--sound/core/seq/oss/seq_oss_synth.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/sound/core/seq/oss/seq_oss_synth.c b/sound/core/seq/oss/seq_oss_synth.c
index 278ebb993122..c93945917235 100644
--- a/sound/core/seq/oss/seq_oss_synth.c
+++ b/sound/core/seq/oss/seq_oss_synth.c
@@ -617,13 +617,14 @@ int
snd_seq_oss_synth_make_info(struct seq_oss_devinfo *dp, int dev, struct synth_info *inf)
{
struct seq_oss_synth *rec;
+ struct seq_oss_synthinfo *info = get_synthinfo_nospec(dp, dev);
- if (dev < 0 || dev >= dp->max_synthdev)
+ if (!info)
return -ENXIO;
- if (dp->synths[dev].is_midi) {
+ if (info->is_midi) {
struct midi_info minf;
- snd_seq_oss_midi_make_info(dp, dp->synths[dev].midi_mapped, &minf);
+ snd_seq_oss_midi_make_info(dp, info->midi_mapped, &minf);
inf->synth_type = SYNTH_TYPE_MIDI;
inf->synth_subtype = 0;
inf->nr_voices = 16;