[PATCH 4/5] USB: legousbtower: fix use-after-free on release

[Johan Hovold]

The driver was accessing its struct usb_device in its release()
callback without holding a reference. This would lead to a
use-after-free whenever the device was disconnected while the character
device was still open.

Fixes: fef526cae700 ("USB: legousbtower: remove custom debug macro")
Cc: stable <sta...@vger.kernel.org>     # 3.12
Signed-off-by: Johan Hovold <jo...@kernel.org>
---
 drivers/usb/misc/legousbtower.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
index 44d6a3381804..9d4c52a7ebe0 100644
--- a/drivers/usb/misc/legousbtower.c
+++ b/drivers/usb/misc/legousbtower.c
@@ -296,6 +296,7 @@ static inline void tower_delete (struct lego_usb_tower *dev)
        kfree (dev->read_buffer);
        kfree (dev->interrupt_in_buffer);
        kfree (dev->interrupt_out_buffer);
+       usb_put_dev(dev->udev);
        kfree (dev);
 }
 
@@ -810,7 +811,7 @@ static int tower_probe (struct usb_interface *interface, 
const struct usb_device
 
        mutex_init(&dev->lock);
 
-       dev->udev = udev;
+       dev->udev = usb_get_dev(udev);
        dev->open_count = 0;
        dev->disconnected = 0;
 
-- 
2.23.0