CVE-2024-46689 soc: qcom: cmd-db: Map shared memory as WC, not WB
A Linux kernel vulnerability causes a denial of service via an endless loop in Trust Zone when using non-default hypervisors like Xen or KVM.
- 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-2024-46689?
CVE-2024-46689 is a medium-severity denial of service vulnerability in Linux kernel, published on 13 Sep 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:
soc: qcom: cmd-db: Map shared memory as WC, not WB
Linux does not write into cmd-db region. This region of memory is write protected by XPU. XPU may sometime falsely detect clean cache eviction as "write" into the write protected region leading to secure interrupt which causes an endless loop somewhere in Trust Zone.
The only reason it is working right now is because Qualcomm Hypervisor maps the same region as Non-Cacheable memory in Stage 2 translation tables. The issue manifests if we want to use another hypervisor (like Xen or KVM), which does not know anything about those specific mappings.
Changing the mapping of cmd-db memory from MEMREMAP_WB to MEMREMAP_WT/WC removes dependency on correct mappings in Stage 2 tables. This patch fixes the issue by updating the mapping to MEMREMAP_WC.
I tested this on SA8155P with Xen.
Weakness: CWE-787
Which versions are affected by CVE-2024-46689?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-46689?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-46689 being exploited?
There is no known exploitation of CVE-2024-46689 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-49377, BELL-CVE-2024-46689, DEBIAN-CVE-2024-46689, GHSA-9hw6-9frh-hxrg, UBUNTU-CVE-2024-46689.