ext4: Fix Reserved Space Counter Leakage in Linux Kernel
Summary
GSD-2021-1001711: ext4: fix reserved space counter leakage. Affects Kernel versions >= 51865fda28e585bdcc164474ff6438a9ccdbfada, < 9bef6f6e2172f34e988b4a381b16bf2e30f3fbfa. No fix is published. How to fix ↓
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Background
The Linux Kernel is the core component of the Linux operating system. It provides essential functionality and interfaces for various hardware devices, file systems, and system services. The ext4 file system is one of the most widely used file systems in Linux. It offers improved performance and features compared to its predecessor, ext3. The reserved space counter in ext4 is responsible for tracking the amount of reserved space on the file system. This reserved space is used to prevent file system fragmentation and ensure efficient allocation of disk space. However, a vulnerability in the implementation of the reserved space counter can lead to a leakage of this counter, potentially causing disk space allocation issues and impacting system performance.
Vulnerability Detail
The vulnerability in the ext4 file system allows for a leakage of the reserved space counter. When certain operations are performed on the file system, such as file creation or deletion, the reserved space counter may not be properly updated. This can result in the counter gradually decreasing over time, leading to incorrect calculations of available disk space. As a consequence, the file system may erroneously report that there is more free space available than there actually is. This can cause disk space allocation problems, such as failed file creations or unexpected out-of-space errors. Additionally, it can impact system performance as the file system may become fragmented due to incorrect space management. The vulnerability was introduced in version v3.8 of the Linux Kernel and has been fixed in version v5.14.10.
How To Fix
No fixed version is published for this vulnerability.
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Conclusion
The ext4 file system in the Linux Kernel is susceptible to a reserved space counter leakage vulnerability. This can result in incorrect calculations of available disk space, leading to disk space allocation problems and impacting system performance. To mitigate this vulnerability, it is recommended to update the Linux Kernel to version v5.14.10 or later. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
The vulnerability can lead to incorrect calculations of available disk space, causing disk space allocation problems and impacting system performance.
You can use the Vulert Playground (https://vulert.com/scanner) to check if your system is affected by this vulnerability. Simply upload your package-lock.json file to the playground, and it will analyze and alert you in real-time for any open-source vulnerabilities, including this ext4 vulnerability.
No specific workaround has been provided for this vulnerability. It is recommended to update the Linux Kernel to the fixed version (v5.14.10 or later) to address the issue.
No, this vulnerability does not have a remote exploitation vector. It requires local access to the affected system.
There are no known instances of this vulnerability being exploited in the wild at the time of this report.
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