From: Oliver Neukum <oneukum@suse.com>
Date: Wed, 16 Mar 2016 12:26:17 +0000 (+0100)
Subject: USB: usb_driver_claim_interface: add sanity checking
X-Git-Tag: v4.6-rc1~98^2~2
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=0b818e3956fc1ad976bee791eadcbb3b5fec5bfd;p=linux.git

USB: usb_driver_claim_interface: add sanity checking

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@suse.com>
CC: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 56593a9a8726..2057d91d8336 100644
--- 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;