CVE-2023-52629: sh: push-switch: Reorder cleanup operations to avoid use-after-free bug
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.
Classification
CVE ID: CVE-2023-52629
Affected Products
Vendor: Linux
Product: Linux
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.04% (probability of being exploited)
EPSS Percentile: 11.44% (scored less or equal to compared to others)
EPSS Date: 2025-02-03 (when was this score calculated)
References
https://git.kernel.org/stable/c/610dbd8ac271aa36080aac50b928d700ee3fe4dehttps://git.kernel.org/stable/c/246f80a0b17f8f582b2c0996db02998239057c65