[PATCH] ALSA: seq: oss: Fix missing error check in snd_seq_oss_synth_make_info()

[Takashi Iwai]

snd_seq_oss_synth_make_info() didn't check the error code from
snd_seq_oss_midi_make_info(), and this leads to the call of strlcpy()
with the uninitialized string as the source, which may lead to the
access over the limit.

Add the proper error check for avoiding the failure.

Reported-by: syzbot+e42504ff21cff05a595f at syzkaller.appspotmail.com
Cc: <stable at vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/core/seq/oss/seq_oss_synth.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/core/seq/oss/seq_oss_synth.c b/sound/core/seq/oss/seq_oss_synth.c
index 11554d0412f0..1b8409ec2c97 100644
--- a/sound/core/seq/oss/seq_oss_synth.c
+++ b/sound/core/seq/oss/seq_oss_synth.c
@@ -611,7 +611,8 @@ snd_seq_oss_synth_make_info(struct seq_oss_devinfo *dp, int dev, struct synth_in
 
 	if (info->is_midi) {
 		struct midi_info minf;
-		snd_seq_oss_midi_make_info(dp, info->midi_mapped, &minf);
+		if (snd_seq_oss_midi_make_info(dp, info->midi_mapped, &minf))
+			return -ENXIO;
 		inf->synth_type = SYNTH_TYPE_MIDI;
 		inf->synth_subtype = 0;
 		inf->nr_voices = 16;
-- 
2.26.2