CISA Known Exploited Vulnerability (KEV)
Description
In the Linux kernel, the following vulnerability has been resolved:
posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()
If an exiting non-autoreaping task has already passed exit_notify() and
calls handle_posix_cpu_timers() from IRQ, it can be reaped by its parent
or debugger right after unlock_task_sighand().
If a concurrent posix_cpu_timer_del() runs at that moment, it won’t be
able to detect timer->it.cpu.firing != 0: cpu_timer_task_rcu() and/or
lock_task_sighand() will fail.
Add the tsk->exit_state check into run_posix_cpu_timers() to fix this.
This fix is not needed if CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y, because
exit_task_work() is called before exit_notify(). But the check still
makes sense, task_work_add(&tsk->posix_cputimers_work.work) will fail
anyway in this case.
References
- https://git.kernel.org/stable/c/2c72fe18cc5f9f1750f5bc148cf1c94c29e106ff
- https://git.kernel.org/stable/c/2f3daa04a9328220de46f0d5c919a6c0073a9f0b
- https://git.kernel.org/stable/c/460188bc042a3f40f72d34b9f7fc6ee66b0b757b
- https://git.kernel.org/stable/c/764a7a5dfda23f69919441f2eac2a83e7db6e5bb
- https://git.kernel.org/stable/c/78a4b8e3795b31dae58762bc091bb0f4f74a2200
- https://git.kernel.org/stable/c/c076635b3a42771ace7d276de8dc3bc76ee2ba1b
- https://git.kernel.org/stable/c/c29d5318708e67ac13c1b6fc1007d179fb65b4d7
- https://git.kernel.org/stable/c/f90fff1e152dedf52b932240ebbd670d83330eca
Weakness Enumeration
| CWE-ID | CWE Name |
|---|---|
|
CWE-367 |
Time-of-check Time-of-use (TOCTOU) Race Condition |