USB: usb_driver_claim_interface: add sanity checking

oneukum · gregkh · commit 0b818e3956fc · 2016-03-18T09:19:02.000-07:00
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 &lt;ONeukum@suse.com&gt;
CC: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
@@ -502,11 +502,15 @@ 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;
 
