CVE-2024-40943
📋 TL;DR
A race condition vulnerability in the Linux kernel's OCFS2 filesystem allows concurrent hole punching (fallocate) operations to corrupt filesystem metadata during AIO+DIO (asynchronous/direct I/O) writes. This affects Linux systems using the OCFS2 filesystem, potentially causing filesystem corruption and read-only mounts.
💻 Affected Systems
- Linux kernel with OCFS2 filesystem support
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Filesystem corruption leading to data loss, system crashes, or forced read-only mounts requiring filesystem repair tools.
Likely Case
Filesystem corruption requiring fsck.ocfs2 repair, temporary service disruption during repair, and potential data loss in affected files.
If Mitigated
Minor performance impact from the fix's synchronization mechanism, but no data corruption.
🎯 Exploit Status
Requires local access, specific timing conditions, and OCFS2 usage. Discovered through fstests rather than malicious exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 050ce8af6838c71e872e982b50d3f1bec21da40e and related fixes
Vendor Advisory: https://git.kernel.org/stable/c/050ce8af6838c71e872e982b50d3f1bec21da40e
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify OCFS2 filesystems mount without errors.
🔧 Temporary Workarounds
Avoid concurrent operations
linuxPrevent simultaneous AIO+DIO writes and hole punching operations on OCFS2 filesystems
Use alternative filesystem
linuxConsider using ext4 or other filesystems that don't have this race condition
🧯 If You Can't Patch
- Monitor OCFS2 filesystems for corruption errors and run fsck.ocfs2 regularly
- Implement application-level controls to avoid concurrent AIO+DIO writes and hole punching
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if OCFS2 is in use: 'uname -r' and 'mount | grep ocfs2'Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and test with fstests/generic/300📡 Detection & Monitoring
Log Indicators:
- OCFS2 ERROR messages about extent corruption
- Filesystem going read-only
- fsck.ocfs2 required messages
SIEM Query:
source="kernel" AND ("OCFS2: ERROR" OR "On-disk corruption discovered" OR "File system is now read-only")🔗 References
- https://git.kernel.org/stable/c/050ce8af6838c71e872e982b50d3f1bec21da40e
- https://git.kernel.org/stable/c/117b9c009b72a6c2ebfd23484354dfee2d9570d2
- https://git.kernel.org/stable/c/38825ff9da91d2854dcf6d9ac320a7e641e10f25
- https://git.kernel.org/stable/c/3c26b5d21b1239e9c7fd31ba7d9b2d7bdbaa68d9
- https://git.kernel.org/stable/c/3c361f313d696df72f9bccf058510e9ec737b9b1
- https://git.kernel.org/stable/c/952b023f06a24b2ad6ba67304c4c84d45bea2f18
- https://git.kernel.org/stable/c/e8e2db1adac47970a6a9225f3858e9aa0e86287f
- https://git.kernel.org/stable/c/ea042dc2bea19d72e37c298bf65a9c341ef3fff3
- https://git.kernel.org/stable/c/050ce8af6838c71e872e982b50d3f1bec21da40e
- https://git.kernel.org/stable/c/117b9c009b72a6c2ebfd23484354dfee2d9570d2
- https://git.kernel.org/stable/c/38825ff9da91d2854dcf6d9ac320a7e641e10f25
- https://git.kernel.org/stable/c/3c26b5d21b1239e9c7fd31ba7d9b2d7bdbaa68d9
- https://git.kernel.org/stable/c/3c361f313d696df72f9bccf058510e9ec737b9b1
- https://git.kernel.org/stable/c/952b023f06a24b2ad6ba67304c4c84d45bea2f18
- https://git.kernel.org/stable/c/e8e2db1adac47970a6a9225f3858e9aa0e86287f
- https://git.kernel.org/stable/c/ea042dc2bea19d72e37c298bf65a9c341ef3fff3
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
