Embedding the ctl_dev in the snd_card object may result in UAF when
the delayed kobj release is used; at the delayed kobj release, it
still accesses the struct device itself while the card memory (that
embeds the struct device) may be already gone.

As a workaround, detach the struct device from the card object by
allocating via the new snd_device_alloc() helper.  The rest are just
replacing ctl_dev access to the pointer.

This is based on the fix Curtis posted initially.  In this patch, the
changes are split and use the new helper function instead.

Link: https://lore.kernel.org/r/20230801171928.1460120-1-cujomalainey@chromium.org
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
Tested-by: Curtis Malainey <cujomalainey@chromium.org>
Link: https://lore.kernel.org/r/20230816160252.23396-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

For reducing the unnecessary use of controls_rwsem in the drivers,
this patch adds a new variant for snd_ctl_find_*() helpers:
snd_ctl_find_id_locked() and snd_ctl_find_numid_locked() look for a
kctl element inside the card->controls_rwsem -- that is, doing the
very same as what snd_ctl_find_id() and snd_ctl_find_numid() did until
now.  snd_ctl_find_id() and snd_ctl_find_numid() remain same,
i.e. still unlocked version, but they will be switched to locked
version once after all callers are replaced.

The patch also replaces the calls of snd_ctl_find_id() and
snd_ctl_find_numid() in a few places; all of those are places where we
know that the functions are called properly with controls_rwsem held.
All others are without rwsem (although they should have been).

After this patch, we'll turn on the locking in snd_ctl_find_id() and
snd_ctl_find_numid() to be more race-free.

Link: https://lore.kernel.org/r/20230718141304.1032-10-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Now that the driver core allows for struct class to be in read-only
memory, making all 'class' structures to be declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Ivan Orlov <ivan.orlov0322@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: alsa-devel@alsa-project.org
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230620175633.641141-2-gregkh@linuxfoundation.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

The use of strncpy() in the set_led_id() was incorrect.
The len variable should use 'min(sizeof(buf2) - 1, count)'
expression.

Use strscpy() function to simplify things and handle the error gracefully.

Fixes: a135dfb5de15 ("ALSA: led control - add sysfs kcontrol LED marking layer")
Reported-by: yang.yang29@zte.com.cn
Link: https://lore.kernel.org/alsa-devel/202301091945513559977@zte.com.cn/
Cc: <stable@vger.kernel.org>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

For sysfs outputs, it's safer to use a new helper, sysfs_emit(),
instead of the raw sprintf() & co.  This patch replaces such sprintf()
calls with sysfs_emit() while simplifying the open code in
list_show().

Link: https://lore.kernel.org/r/20220801165639.26030-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Fix a sparse warning that complains about the inconsistent type
assignment for iface, which is a restricted type of
snd_ctl_elem_iface_t.

Fixes: a135dfb5de15 ("ALSA: led control - add sysfs kcontrol LED marking layer")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/202111201028.xduVYgH5-lkp@intel.com
Link: https://lore.kernel.org/r/20211123170247.2962-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

strlcpy is deprecated, use its safe replacement

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Bard Liao <bard.liao@intel.com>
Reviewed-by: Paul Olaru <paul.olaru@oss.nxp.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20210812225904.171529-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

The str variable should be always initialized before use even if
the switch covers all cases. This is a minimalistic fix: Assign NULL,
the sprintf() may print '(null)' if something is corrupted.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210614071710.1786866-1-perex@perex.cz
Signed-off-by: Takashi Iwai <tiwai@suse.de>

The snd_ctl_led_sysfs_add and snd_ctl_led_sysfs_remove should contain
the refcount operations in pair. However, snd_ctl_led_sysfs_remove fails
to decrease the refcount to zero, which causes device_release never to
be invoked. This leads to memory leak to some resources, like struct
device_private. In addition, we also free some other similar memory
leaks in snd_ctl_led_init/snd_ctl_led_exit.

Fix this by replacing device_del to device_unregister
in snd_ctl_led_sysfs_remove/snd_ctl_led_init/snd_ctl_led_exit.

Note that, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device will
call kobject_release and delay the release of kobject, which will cause
use-after-free when the memory backing the kobject is freed at once.

Reported-by: syzbot+08a7d8b51ea048a74ffb@syzkaller.appspotmail.com
Fixes: a135dfb5de15 ("ALSA: led control - add sysfs kcontrol LED marking layer")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210602034136.2762497-1-mudongliangabcd@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>