[PATCH 4.2.y-ckt 082/206] USB: serial: quatech2: fix use-after-free in probe error path

[Kamal Mostafa]

4.2.8-ckt12 -stable review patch.  If anyone has any objections, please let me know.

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

From: Johan Hovold <johan at kernel.org>

commit 028c49f5e02a257c94129cd815f7c8485f51d4ef upstream.

The interface read URB is submitted in attach, but was only unlinked by
the driver at disconnect.

In case of a late probe error (e.g. due to failed minor allocation),
disconnect is never called and we would end up with active URBs for an
unbound interface. This in turn could lead to deallocated memory being
dereferenced in the completion callback.

Fixes: f7a33e608d9a ("USB: serial: add quatech2 usb to serial driver")
Signed-off-by: Johan Hovold <johan at kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/serial/quatech2.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c
index 504f5bf..b18974c 100644
--- a/drivers/usb/serial/quatech2.c
+++ b/drivers/usb/serial/quatech2.c
@@ -141,6 +141,7 @@ static void qt2_release(struct usb_serial *serial)
 
 	serial_priv = usb_get_serial_data(serial);
 
+	usb_kill_urb(serial_priv->read_urb);
 	usb_free_urb(serial_priv->read_urb);
 	kfree(serial_priv->read_buffer);
 	kfree(serial_priv);
-- 
2.7.4