In the Linux kernel, the following vulnerability has been resolved:
ALSA: control: Don't add invalid kcontrols to LED layer
The kcontrol LED state layer tries to track the all associated
kcontrol elements with naive assumptions that they are readable.
But one can create a write-only element that has no get callback (even
a user element can do it), and this may lead to a NULL dereference at
the call chain of snd_ctl_led_notify(), as found by syzkaller.
For avoiding the Oops, add a sanity check of the kcontrol's info and
get callbacks, and just skip the invalid kcontrols before assigning
the kctl to the LED layer.
Ссылки 5
https://git.kernel.org/stable/c/18c08f84ca483029f04e426ec7ca3b5d3684cf22
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/2f0c97b1a32fba8e81a69f6231aa0b3c9b6bc581
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/3d20cd049fc5f51f80e24a2db7a3cf00593c79e4
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/6e152cbfac3a2a62f79df7d23d621917c20367eb
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/74e3b979ce8b78a690f8b94ccf2e2c965f7f5c11
416baaa9-dc9f-4396-8d5f-8c081fb06d67