CVE-2024-46689: soc: qcom: cmd-db: Map shared memory as WC, not WB
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 MEMREMAPWB to MEMREMAPWT/WC removes dependency on correct mappings in Stage 2 tables. This patch fixes the issue by updating the mapping to MEMREMAPWC.
I tested this on SA8155P with Xen.
Other sources
soc: qcom: cmd-db: Map shared memory as WC not WB
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.22-1Fixed in 6.12.25-1 - Upgrade
Upgrade
debian/linux-6.1to a version that resolves this vulnerability.Fixed in 6.1.129-1~deb11u1 - Configuration
Update the cmd-db shared memory mapping from MEMREMAP_WB to MEMREMAP_WC (WC instead of WB) as per the resolved vulnerability fix ('soc: qcom: cmd-db: Map shared memory as WC, not WB').
Linux kernel (soc: qcom: cmd-db) cmd-db shared memory mapping = MEMREMAP_WC
Event History
Frequently Asked Questions
What is the severity of CVE-2024-46689?
CVE-2024-46689 has not been assigned a specific severity rating but pertains to issues related to memory management in the Linux kernel.
How do I fix CVE-2024-46689?
To fix CVE-2024-46689, update your Linux kernel to versions 5.10.226-1, 6.1.123-1, 6.1.119-1, 6.12.10-1, or 6.12.11-1.
Which systems are affected by CVE-2024-46689?
CVE-2024-46689 affects various versions of the Linux kernel, particularly those prior to specific patched versions listed in the remediation.
Is CVE-2024-46689 remote exploit capable?
CVE-2024-46689's details do not indicate that it is capable of being exploited remotely.
What impact does CVE-2024-46689 have on system performance?
CVE-2024-46689 may lead to issues with memory handling, potentially impacting system performance and reliability.