CVE-2022-49169
📋 TL;DR
This CVE describes a race condition deadlock vulnerability in the Linux kernel's F2FS filesystem. When multiple processes attempt to access F2FS statistics simultaneously, they can deadlock, causing system hangs and denial of service. This affects any Linux system using the F2FS filesystem.
💻 Affected Systems
- Linux kernel with F2FS 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 →⚠️ Risk & Real-World Impact
Worst Case
Complete system hang requiring hard reboot, potential data corruption if filesystem operations are interrupted, and extended service downtime.
Likely Case
System becomes unresponsive when specific F2FS operations are performed concurrently, requiring manual intervention to recover.
If Mitigated
Minor performance impact during F2FS operations with proper locking mechanisms in place.
🎯 Exploit Status
Exploitation requires local access and specific timing conditions to trigger the race condition.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 2eff60346e7ae1a24cd868b8fdcf58e946e7dde1, 738886004bd2885ac2db0bc63b4874aa471ca87e, 98237fcda4a24e67b0a4498c17d5aa4ad4537bc7, ec4187d45cc1c2d69fffeee5fa6aa4cb62477cfb
Vendor Advisory: https://git.kernel.org/stable/c/2eff60346e7ae1a24cd868b8fdcf58e946e7dde1
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Reboot system to load new kernel. 3. Verify F2FS module loads correctly.
🔧 Temporary Workarounds
Disable F2FS filesystem
linuxPrevent use of F2FS filesystem to avoid vulnerability
# Remove F2FS module if loaded
rmmod f2fs
# Blacklist F2FS module
echo 'blacklist f2fs' >> /etc/modprobe.d/blacklist-f2fs.conf
Avoid concurrent F2FS operations
linuxLimit simultaneous access to F2FS filesystem statistics
# Monitor for concurrent F2FS operations
# Implement process controls to prevent simultaneous stat access
🧯 If You Can't Patch
- Restrict user access to systems using F2FS filesystem
- Implement monitoring for system hangs and have reboot procedures ready
🔍 How to Verify
Check if Vulnerable:
Check if F2FS module is loaded and kernel version is vulnerable: lsmod | grep f2fs && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and test F2FS operations don't cause hangs📡 Detection & Monitoring
Log Indicators:
- System hangs with F2FS-related processes in D state
- Kernel logs showing mutex_lock contention in f2fs functions
- Processes stuck in stat_show or f2fs_destroy_stats
Network Indicators:
- None - local vulnerability only
SIEM Query:
Processes with state:D AND (command:cat OR command:umount) AND module:f2fs