[PATCH 1/2] ALSA: timer: Fix leak in events via snd_timer_user_ccallback

[Luis Henriques]

From: Kangjie Lu <kangjielu at gmail.com>

The stack object “r1” 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 at gatech.edu>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
(cherry picked from commit 9a47e9cff994f37f7f0dbd9ae23740d0f64f9fe6)
CVE-2016-4578
BugLink: https://bugs.launchpad.net/bugs/1581866
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 sound/core/timer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sound/core/timer.c b/sound/core/timer.c
index beb41ecb2730..c72023235f0a 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -1213,6 +1213,7 @@ static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
 		tu->tstamp = *tstamp;
 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
 		return;
+	memset(&r1, 0, sizeof(r1));
 	r1.event = event;
 	r1.tstamp = *tstamp;
 	r1.val = resolution;