[PATCH 3.19.y-ckt 104/170] USB: usb_driver_claim_interface: add sanity checking

From: Kamal Mostafa
Date: Fri Apr 01 2016 - 21:16:21 EST


3.19.8-ckt18 -stable review patch. If anyone has any objections, please let me know.

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

From: Oliver Neukum <oneukum@xxxxxxxx>

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@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
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 818369a..7792c0e 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -499,11 +499,15 @@ 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;

--
2.7.4