Input: lkkbd - disable pending work before freeing device

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: Input: lkkbd - disable pending work before freeing device lkkbd_interrupt() schedules lk->tq via schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields. lkkbd_disconnect() and error paths in lkkbd_connect() free the lkkbd structure without preventing the reinit work from being queued again until serio_close() returns. This can allow the work handler to run after the structure has been freed, leading to a potential use-after-free. Use disable_work_sync() instead of cancel_work_sync() to ensure the reinit work cannot be re-queued, and call it both in lkkbd_disconnect() and in lkkbd_connect() error paths after serio_open().

References

• https://git.kernel.org/stable/c/3a7cd1397c209076c371d53bf39a55c138f62342
• https://git.kernel.org/stable/c/cffc4e29b1e2d44ab094cf142d7c461ff09b9104
• https://git.kernel.org/stable/c/e58c88f0cb2d8ed89de78f6f17409d29cfab6c5c