[PATCH 4.4 41/79] USB: adutux: fix use-after-free on release

From: Greg Kroah-Hartman
Date: Wed Oct 16 2019 - 17:53:51 EST


From: Johan Hovold <johan@xxxxxxxxxx>

commit 123a0f125fa3d2104043697baa62899d9e549272 upstream.

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: 66d4bc30d128 ("USB: adutux: remove custom debug macro")
Cc: stable <stable@xxxxxxxxxxxxxxx> # 3.12
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20191009153848.8664-2-johan@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/usb/misc/adutux.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/usb/misc/adutux.c
+++ b/drivers/usb/misc/adutux.c
@@ -152,6 +152,7 @@ static void adu_delete(struct adu_device
kfree(dev->read_buffer_secondary);
kfree(dev->interrupt_in_buffer);
kfree(dev->interrupt_out_buffer);
+ usb_put_dev(dev->udev);
kfree(dev);
}

@@ -681,7 +682,7 @@ static int adu_probe(struct usb_interfac

mutex_init(&dev->mtx);
spin_lock_init(&dev->buflock);
- dev->udev = udev;
+ dev->udev = usb_get_dev(udev);
init_waitqueue_head(&dev->read_wait);
init_waitqueue_head(&dev->write_wait);