CVE-2023-52629 Information

Description

In the Linux kernel the following vulnerability has been resolved:

sh: push-switch: Reorder cleanup operations to avoid use-after-free bug

The original code puts flush_work() before timer_shutdown_sync() in switch_drv_remove(). Although we use flush_work() to stop the worker it could be rescheduled in switch_timer(). As a result a use-after-free bug can occur. The details are shown below:

  (cpu 0)                    |      (cpu 1)

switch_drv_remove() | flush_work() | … | switch_timer // timer | schedule_work(&psw->work) timer_shutdown_sync() | … | switch_work_handler // worker kfree(psw) // free | | psw->state = 0 // use

This patch puts timer_shutdown_sync() before flush_work() to mitigate the bugs. As a result the worker and timer will be stopped safely before the deallocate operations.

Reference

https://git.kernel.org/stable/c/610dbd8ac271aa36080aac50b928d700ee3fe4de https://git.kernel.org/stable/c/246f80a0b17f8f582b2c0996db02998239057c65