[3.16.y-ckt stable] Patch "USB: usb_driver_claim_interface: add sanity checking" has been added to the 3.16.y-ckt tree

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    USB: usb_driver_claim_interface: add sanity checking

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt27.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

---8<------------------------------------------------------------

>From 585a7187f2a3006d776fd170d6e0104a721082f9 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum at suse.com>
Date: Wed, 16 Mar 2016 13:26:17 +0100
Subject: USB: usb_driver_claim_interface: add sanity checking

commit 0b818e3956fc1ad976bee791eadcbb3b5fec5bfd upstream.

Attacks that trick drivers into passing a NULL pointer
to usb_driver_claim_interface() using forged descriptors are
known. This thwarts them by sanity checking.

Signed-off-by: Oliver Neukum <ONeukum at suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/core/driver.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 37c7ce9af220..e7bff99cdb2d 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -515,11 +515,15 @@ static int usb_unbind_interface(struct device *dev)
 int usb_driver_claim_interface(struct usb_driver *driver,
 				struct usb_interface *iface, void *priv)
 {
-	struct device *dev = &iface->dev;
+	struct device *dev;
 	struct usb_device *udev;
 	int retval = 0;
 	int lpm_disable_error;

+	if (!iface)
+		return -ENODEV;
+
+	dev = &iface->dev;
 	if (dev->driver)
 		return -EBUSY;