On 16.08.2017 18:29, Alan Stern wrote:
On Wed, 16 Aug 2017, Anton Vasilyev wrote:
gadget_release() is responsible for cleanup dev memory.
But if net2280_probe() fails after dev allocation, then
gadget_release() become unregistered and dev memory leaks.
This isn't needed if usb_add_gadget_udc_release() is fixed, right?
No, this situation could appear before call
usb_add_gadget_udc_release().
Also net2280_remove() calls usb_del_gadget_udc() which
perform schedule_delayed_work() with gadget_release(), so
it is possible that dev will be deallocated exactly after
this call and leads to use after free.
Where is there a possible use after free?
net2280_remove() continue work with struct net2280 *dev after call
usb_del_gadget_udc(&dev->gadget), but this net2280 *dev could be
deallocated by gadget_release()
The patch moves deallocation from gadget_release() to
net2280_remove().
Alan Stern
--
Anton Vasilyev
Linux Verification Center, ISPRAS
web: http://linuxtesting.org
e-mail: vasilyev@xxxxxxxxx
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