6a4ec6f242
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: 67f8ecc550b5 ("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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.