CVE-2022-48707 cxl/region: Fix null pointer dereference for resetting decoder
A null pointer dereference in the Linux kernel CXL region driver allows local attackers to cause a system crash by destroying a specific CXL memory region configuration.
- 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-2022-48707?
CVE-2022-48707 is a medium-severity vulnerability in Linux kernel, published on 21 May 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:
cxl/region: Fix null pointer dereference for resetting decoder
Not all decoders have a reset callback.
The CXL specification allows a host bridge with a single root port to have no explicit HDM decoders. Currently the region driver assumes there are none. As such the CXL core creates a special pass through decoder instance without a commit/reset callback.
Prior to this patch, the ->reset() callback was called unconditionally when calling cxl_region_decode_reset. Thus a configuration with 1 Host Bridge, 1 Root Port, and one directly attached CXL type 3 device or multiple CXL type 3 devices attached to downstream ports of a switch can cause a null pointer dereference.
Before the fix, a kernel crash was observed when we destroy the region, and a pass through decoder is reset.
The issue can be reproduced as below, 1) create a region with a CXL setup which includes a HB with a single root port under which a memdev is attached directly. 2) destroy the region with cxl destroy-region regionX -f.
Weakness: CWE-476
Which versions are affected by CVE-2022-48707?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-48707?
Apply the vendor's patch.
Is CVE-2022-48707 being exploited?
There is no known exploitation of CVE-2022-48707 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-48707, GHSA-5xfg-8mp6-pr5f, UBUNTU-CVE-2022-48707.