USB: iowarrior: fix use-after-free on release

The driver was accessing its struct usb_interface from its release()
callback without holding a reference. This would lead to a
use-after-free whenever debugging was enabled and the device was
disconnected while its character device was open.

Fixes: 549e83500b80 ("USB: iowarrior: Convert local dbg macro to dev_dbg")
Cc: stable <stable@vger.kernel.org>     # 3.16
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191009104846.5925-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index 4fe1d32..6841267 100644 (file)
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -243,6 +243,7 @@ static inline void iowarrior_delete(struct iowarrior *dev)
        kfree(dev->int_in_buffer);
        usb_free_urb(dev->int_in_urb);
        kfree(dev->read_queue);
+       usb_put_intf(dev->interface);
        kfree(dev);
 }
 
@@ -764,7 +765,7 @@ static int iowarrior_probe(struct usb_interface *interface,
        init_waitqueue_head(&dev->write_wait);
 
        dev->udev = udev;
-       dev->interface = interface;
+       dev->interface = usb_get_intf(interface);
 
        iface_desc = interface->cur_altsetting;
        dev->product_id = le16_to_cpu(udev->descriptor.idProduct);