ALSA: timer: Fix leak in SNDRV_TIMER_IOCTL_PARAMS

commit cec8f96e upstream.

The stack object “tread” has a total size of 32 bytes. Its field
“event” and “val” both contain 4 bytes padding. These 8 bytes
padding bytes are sent to user without being initialized.
Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

sound/core/timer.c

@@ -1750,6 +1750,7 @@ static int snd_timer_user_params(struct file *file,
 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
 		if (tu->tread) {
 			struct snd_timer_tread tread;
+			memset(&tread, 0, sizeof(tread));
 			tread.event = SNDRV_TIMER_EVENT_EARLY;
 			tread.tstamp.tv_sec = 0;
 			tread.tstamp.tv_nsec = 0;