[PATCH 3.16 055/136] USB: adutux: fix use-after-free on release

Ben Hutchings
2019-12-17T00:57:35Z

From: Johan Hovold <johan@kernel.org>

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")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191009153848.8664-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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);
}

@@ -677,7 +678,7 @@ 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);