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[ Upstream commit 627bb528b0 ]
dvb_register_device() dynamically allocates fops with kmemdup()
to set the fops->owner.
And these fops are registered in 'file->f_ops' using replace_fops()
in the dvb_device_open() process, and kfree()d in dvb_free_device().
However, it is not common to use dynamically allocated fops instead
of 'static const' fops as an argument of replace_fops(),
and UAF may occur.
These UAFs can occur on any dvb type using dvb_register_device(),
such as dvb_dvr, dvb_demux, dvb_frontend, dvb_net, etc.
So, instead of kfree() the fops dynamically allocated in
dvb_register_device() in dvb_free_device() called during the
.disconnect() process, kfree() it collectively in exit_dvbdev()
called when the dvbdev.c module is removed.
Link: https://lore.kernel.org/linux-media/20221117045925.14297-4-imv4bel@gmail.com
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.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.