CVE-2022-49316
📋 TL;DR
This Linux kernel vulnerability in NFSv4 client code could cause a deadlock when performing layout operations during file opens. The issue occurs when layout locks are held across multiple RPC calls, potentially triggering a recall that leads to system deadlock. This affects systems using NFSv4 with pNFS (parallel NFS) layouts.
💻 Affected Systems
- Linux kernel
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
System deadlock requiring reboot, causing denial of service for NFS-mounted filesystems and potentially affecting system stability.
Likely Case
Occasional deadlocks during NFS operations requiring manual intervention or system restart to resolve.
If Mitigated
Minor performance impact from additional lock management with no security impact when patched.
🎯 Exploit Status
Exploitation requires specific NFS operations and pNFS configuration. This is a reliability issue rather than a traditional security vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 08d7a26d115cc7892668baa9750f64bd8baca29b, 0ee5b9644f06b4d3cdcd9544f43f63312e425a4c, 6949493884fe88500de4af182588e071cf1544ee, 6b3fc1496e7227cd6a39a80bbfb7588ef7c7a010, a2b3be930e79cc5d9d829f158e31172b2043f0cd
Vendor Advisory: https://git.kernel.org/stable/c/08d7a26d115cc7892668baa9750f64bd8baca29b
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable pNFS layouts
linuxDisable parallel NFS (pNFS) layouts to avoid the vulnerable code path
mount -t nfs4 -o nolayout server:/share /mountpoint
Use NFSv3 instead of NFSv4
linuxMount filesystems using NFSv3 protocol which doesn't have pNFS support
mount -t nfs -o vers=3 server:/share /mountpoint
🧯 If You Can't Patch
- Implement workarounds to disable pNFS layouts on NFS mounts
- Monitor systems for deadlock symptoms and have reboot procedures ready
🔍 How to Verify
Check if Vulnerable:
Check if system uses NFSv4 with pNFS layouts and has unpatched kernel. Use: cat /proc/mounts | grep nfs4Check Version:
uname -rVerify Fix Applied:
Check kernel version contains the fix commits. Use: uname -r and verify with distribution patch notes📡 Detection & Monitoring
Log Indicators:
- System hangs during NFS operations
- Kernel messages about NFS deadlocks
- Processes stuck in D state (uninterruptible sleep)
Network Indicators:
- Increased NFS timeout errors
- Unresponsive NFS mounts
SIEM Query:
source="kernel" AND ("NFS" AND ("deadlock" OR "layout" OR "recall"))🔗 References
- https://git.kernel.org/stable/c/08d7a26d115cc7892668baa9750f64bd8baca29b
- https://git.kernel.org/stable/c/0ee5b9644f06b4d3cdcd9544f43f63312e425a4c
- https://git.kernel.org/stable/c/6949493884fe88500de4af182588e071cf1544ee
- https://git.kernel.org/stable/c/6b3fc1496e7227cd6a39a80bbfb7588ef7c7a010
- https://git.kernel.org/stable/c/a2b3be930e79cc5d9d829f158e31172b2043f0cd
- https://git.kernel.org/stable/c/d4c2a041ed3ba114502d5ed6ace5b1a48d637a8e
- https://git.kernel.org/stable/c/ea759ae0a9ae5acee677d722129710ac89cc59c1
