[PATCH 3.18 003/120] ALSA: emu10k1: fix possible info leak to userspace on SNDRV_EMU10K1_IOCTL_INFO

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Willy Tarreau <w@xxxxxx>

commit 49434c6c575d2008c0abbc93e615019f39e01252 upstream.

snd_emu10k1_fx8010_ioctl(SNDRV_EMU10K1_IOCTL_INFO) allocates
memory using kmalloc() and partially fills it by calling
snd_emu10k1_fx8010_info() before returning the resulting
structure to userspace, leaving uninitialized holes. Let's
just use kzalloc() here.

BugLink: http://blog.infosectcbr.com.au/2018/09/linux-kernel-infoleaks.html
Signed-off-by: Willy Tarreau <w@xxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 sound/pci/emu10k1/emufx.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/sound/pci/emu10k1/emufx.c
+++ b/sound/pci/emu10k1/emufx.c
@@ -2521,7 +2521,7 @@ static int snd_emu10k1_fx8010_ioctl(stru
 		emu->support_tlv = 1;
 		return put_user(SNDRV_EMU10K1_VERSION, (int __user *)argp);
 	case SNDRV_EMU10K1_IOCTL_INFO:
-		info = kmalloc(sizeof(*info), GFP_KERNEL);
+		info = kzalloc(sizeof(*info), GFP_KERNEL);
 		if (!info)
 			return -ENOMEM;
 		snd_emu10k1_fx8010_info(emu, info);