[PATCH] USB: iowarrior: fix use-after-free on disconnect

[Johan Hovold]

Submitted write URBs are not stopped on close() and therefore need to be
stopped unconditionally on disconnect() to avoid use-after-free in the
completion handler.

Fixes: b5f8d46867ca ("USB: iowarrior: fix use-after-free after driver unbind")
Fixes: 946b960d13c1 ("USB: add driver for iowarrior devices.")
Reported-by: syzbot+ad2aac2febc3bedf0962@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/all/6a0ce39b.170a0220.39a13.0007.GAE@xxxxxxxxxx/
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---

I happened to see a reply to this syzbot report today and took at look
at the driver. Turns out my fix from 2019 was incomplete.

Johan


 drivers/usb/misc/iowarrior.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index 22504c0a2841..88c6d1d1da11 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -905,13 +905,15 @@ static void iowarrior_disconnect(struct usb_interface *interface)
 	/* prevent device read, write and ioctl */
 	dev->present = 0;
 
+	/* write urbs are not stopped on close() so kill unconditionally */
+	usb_kill_anchored_urbs(&dev->submitted);
+
 	if (dev->opened) {
 		/* There is a process that holds a filedescriptor to the device ,
 		   so we only shutdown read-/write-ops going on.
 		   Deleting the device is postponed until close() was called.
 		 */
 		usb_kill_urb(dev->int_in_urb);
-		usb_kill_anchored_urbs(&dev->submitted);
 		wake_up_interruptible(&dev->read_wait);
 		wake_up_interruptible(&dev->write_wait);
 		mutex_unlock(&dev->mutex);
-- 
2.53.0