CVE-2023-53045

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: u_audio: don't let userspace block driver unbind

In the unbind callback for f_uac1 and f_uac2, a call to snd_card_free()

via g_audio_cleanup() will disconnect the card and then wait for all

resources to be released, which happens when the refcount falls to zero.

Since userspace can keep the refcount incremented by not closing the

relevant file descriptor, the call to unbind may block indefinitely.

This can cause a deadlock during reboot, as evidenced by the following

blocked task observed on my machine:

task:reboot state:D stack:0 pid:2827 ppid:569 flags:0x0000000c

Call trace:

__switch_to+0xc8/0x140

__schedule+0x2f0/0x7c0

schedule+0x60/0xd0

schedule_timeout+0x180/0x1d4

wait_for_completion+0x78/0x180

snd_card_free+0x90/0xa0

g_audio_cleanup+0x2c/0x64

afunc_unbind+0x28/0x60

...

kernel_restart+0x4c/0xac

__do_sys_reboot+0xcc/0x1ec

__arm64_sys_reboot+0x28/0x30

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References