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: v3.2.80~69
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=79a575e829ba789c462c103c54fd9554f60079db;p=pandora-kernel.git

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@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index c105ba32ff02..c5957142d26b 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -428,9 +428,13 @@ 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;
 	int retval = 0;
 
+	if (!iface)
+		return -ENODEV;
+
+	dev = &iface->dev;
 	if (dev->driver)
 		return -EBUSY;