CVE-2024-56621 scsi: ufs: core: Cancel RTC work during ufshcd_remove()
A missing cancellation of RTC work during UFS driver removal causes a kernel NULL pointer dereference, leading to a system crash.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-56621?
CVE-2024-56621 is a medium-severity vulnerability in Linux kernel, published on 27 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: Cancel RTC work during ufshcd_remove()
Currently, RTC work is only cancelled during __ufshcd_wl_suspend(). When ufshcd is removed in ufshcd_remove(), RTC work is not cancelled. Due to this, any further trigger of the RTC work after ufshcd_remove() would result in a NULL pointer dereference as below:
Unable to handle kernel NULL pointer dereference at virtual address 00000000000002a4 Workqueue: events ufshcd_rtc_work Call trace: _raw_spin_lock_irqsave+0x34/0x8c pm_runtime_get_if_active+0x24/0xb4 ufshcd_rtc_work+0x124/0x19c process_scheduled_works+0x18c/0x2d8 worker_thread+0x144/0x280 kthread+0x11c/0x128 ret_from_fork+0x10/0x20
Since RTC work accesses the ufshcd internal structures, it should be cancelled when ufshcd is removed. So do that in ufshcd_remove(), as per the order in ufshcd_init().
Weakness: CWE-476
Which versions are affected by CVE-2024-56621?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-56621?
Apply the vendor's patch.
Is CVE-2024-56621 being exploited?
There is no known exploitation of CVE-2024-56621 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2024-56621, DEBIAN-CVE-2024-56621, GHSA-g3c8-2g4x-qq2h, UBUNTU-CVE-2024-56621.