CVE-2024-44937 platform/x86: intel-vbtn: Protect ACPI notify handler against recursion
A race condition in the Intel virtual button driver can cause a kernel NULL pointer dereference and system crash during device undocking.
- 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-2024-44937?
CVE-2024-44937 is a medium-severity vulnerability in Linux kernel, published on 26 Aug 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:
platform/x86: intel-vbtn: Protect ACPI notify handler against recursion
Since commit e2ffcda16290 ("ACPI: OSL: Allow Notify () handlers to run on all CPUs") ACPI notify handlers like the intel-vbtn notify_handler() may run on multiple CPU cores racing with themselves.
This race gets hit on Dell Venue 7140 tablets when undocking from the keyboard, causing the handler to try and register priv->switches_dev twice, as can be seen from the dev_info() message getting logged twice:
[ 83.861800] intel-vbtn INT33D6:00: Registering Intel Virtual Switches input-dev after receiving a switch event [ 83.861858] input: Intel Virtual Switches as /devices/pci0000:00/0000:00:1f.0/PNP0C09:00/INT33D6:00/input/input17 [ 83.861865] intel-vbtn INT33D6:00: Registering Intel Virtual Switches input-dev after receiving a switch event
After which things go seriously wrong: [ 83.861872] sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:1f.0/PNP0C09:00/INT33D6:00/input/input17' ... [ 83.861967] kobject: kobject_add_internal failed for input17 with -EEXIST, don't try to register things with the same name in the same directory. [ 83.877338] BUG: kernel NULL pointer dereference, address: 0000000000000018 ...
Protect intel-vbtn notify_handler() from racing with itself with a mutex to fix this.
Weakness: CWE-476
Which versions are affected by CVE-2024-44937?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-44937?
Apply the vendor's patch.
Is CVE-2024-44937 being exploited?
There is no known exploitation of CVE-2024-44937 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2024-44937, DEBIAN-CVE-2024-44937, GHSA-w3ph-7hx8-wxg6, UBUNTU-CVE-2024-44937.