Hyunwoo Kim 627bb528b0 media: dvb-core: Fix use-after-free due to race at dvb_register_device()
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>
2023-05-14 06:30:58 +01:00
..
2023-02-26 11:47:26 -08:00
2023-04-15 08:53:31 +01:00
2021-10-04 07:52:13 +02:00
2022-10-22 15:30:15 -07:00
2020-11-16 10:31:16 +01:00
2021-11-22 07:47:13 +00:00