Jann Horn c2e39d5df0 HID: uhid: Fix worker destroying device without any protection ...

commit 4ea5763fb79ed89b3bdad455ebf3f33416a81624 upstream.

uhid has to run hid_add_device() from workqueue context while allowing
parallel use of the userspace API (which is protected with ->devlock).
But hid_add_device() can fail. Currently, that is handled by immediately
destroying the associated HID device, without using ->devlock - but if
there are concurrent requests from userspace, that's wrong and leads to
NULL dereferences and/or memory corruption (via use-after-free).

Fix it by leaving the HID device as-is in the worker. We can clean it up
later, either in the UHID_DESTROY command handler or in the ->release()
handler.

Cc: stable@vger.kernel.org
Fixes: 67f8ecc550 ("HID: uhid: fix timeout when probe races with IO")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2022-01-27 10:53:40 +01:00

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