CVE-2024-26623 pds_core: Prevent race issues involving the adminq
A race condition in the pds_core driver can cause a NULL pointer dereference, leading to a system crash or denial of service.
- 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-2024-26623?
CVE-2024-26623 is a high-severity vulnerability in Linux kernel, published on 6 Mar 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:
pds_core: Prevent race issues involving the adminq
There are multiple paths that can result in using the pdsc's adminq.
[1] pdsc_adminq_isr and the resulting work from queue_work(), i.e. pdsc_work_thread()->pdsc_process_adminq()
[2] pdsc_adminq_post()
When the device goes through reset via PCIe reset and/or a fw_down/fw_up cycle due to bad PCIe state or bad device state the adminq is destroyed and recreated.
A NULL pointer dereference can happen if [1] or [2] happens after the adminq is already destroyed.
In order to fix this, add some further state checks and implement reference counting for adminq uses. Reference counting was used because multiple threads can attempt to access the adminq at the same time via [1] or [2]. Additionally, multiple clients (i.e. pds-vfio-pci) can be using [2] at the same time.
The adminq_refcnt is initialized to 1 when the adminq has been allocated and is ready to use. Users/clients of the adminq (i.e. [1] and [2]) will increment the refcnt when they are using the adminq. When the driver goes into a fw_down cycle it will set the PDSC_S_FW_DEAD bit and then wait for the adminq_refcnt to hit 1. Setting the PDSC_S_FW_DEAD before waiting will prevent any further adminq_refcnt increments. Waiting for the adminq_refcnt to hit 1 allows for any current users of the adminq to finish before the driver frees the adminq. Once the adminq_refcnt hits 1 the driver clears the refcnt to signify that the adminq is deleted and cannot be used. On the fw_up cycle the driver will once again initialize the adminq_refcnt to 1 allowing the adminq to be used again.
Weakness: CWE-476
Which versions are affected by CVE-2024-26623?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-26623?
Apply the vendor's patch.
Is CVE-2024-26623 being exploited?
There is no known exploitation of CVE-2024-26623 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2024-26623, DEBIAN-CVE-2024-26623, GHSA-3fv7-f54h-j866, UBUNTU-CVE-2024-26623.