[PATCH 1/2][Precise][Trusty] USB: usbfs: fix potential infoleak in devio

[Luis Henriques]

From: Kangjie Lu <kangjielu at gmail.com>

The stack object “ci” has a total size of 8 bytes. Its last 3 bytes
are padding bytes which are not initialized and leaked to userland
via “copy_to_user”.

Signed-off-by: Kangjie Lu <kjlu at gatech.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(backported from commit 681fef8380eb818c0b845fca5d2ab1dcbab114ee)
CVE-2016-4482
BugLink: https://bugs.launchpad.net/bugs/1578493
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/core/devio.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 64340f3e0792..ed11901ab8ab 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1005,10 +1005,11 @@ static int proc_getdriver(struct dev_state *ps, void __user *arg)
 
 static int proc_connectinfo(struct dev_state *ps, void __user *arg)
 {
-	struct usbdevfs_connectinfo ci = {
-		.devnum = ps->dev->devnum,
-		.slow = ps->dev->speed == USB_SPEED_LOW
-	};
+	struct usbdevfs_connectinfo ci;
+
+	memset(&ci, 0, sizeof(ci));
+	ci.devnum = ps->dev->devnum;
+	ci.slow = ps->dev->speed == USB_SPEED_LOW;
 
 	if (copy_to_user(arg, &ci, sizeof(ci)))
 		return -EFAULT;