ALSA: timer: Fix leak in events via snd_timer_user_ccallback

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@gatech.edu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Orabug: 25059885
CVE: CVE-2016-4578
Mainline v4.7 commit 9a47e9cff994f37f7f0dbd9ae23740d0f64f9fe6
Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com>

diff --git a/sound/core/timer.c b/sound/core/timer.c
index 72eb1dd6dc7640fe033573789d726bba045fd487..c85abca92ece3b70e5957476a0278021fe977dfc 100644 (file)
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -1171,6 +1171,7 @@ 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;