NFSD: Fix READDIR buffer overflow in Kernel
Summary
GSD-2021-1002818: NFSD: Fix READDIR buffer overflow. Affects Kernel versions >= f5dcccd647da513a89f3b6ca392b0c1eb050b9fc, < eabc0aab98e5218ceecd82069b0d6fdfff5ee885. No fix is published. How to fix ↓
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Background
The Kernel is a critical component of the Linux operating system that provides core functionality and interfaces with hardware devices. It manages system resources, facilitates communication between software and hardware, and supports various file systems. The Network File System (NFS) is a distributed file system protocol that allows remote access to files over a network. The NFS server daemon (NFSD) is responsible for handling NFS requests on the server side. This vulnerability affects the NFSD component of the Kernel.
Vulnerability Detail
The vulnerability in NFSD is a buffer overflow issue that occurs during the READDIR operation. When processing a READDIR request, NFSD fails to properly validate the size of the buffer used to store directory entries. As a result, an attacker can craft a malicious READDIR request that overflows the buffer, potentially leading to arbitrary code execution or a denial-of-service condition. This vulnerability was introduced in version v5.13 of the Linux Kernel and has been fixed in version v5.15.12.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, users can disable the NFSD component if it is not required for their system. This can be done by stopping the NFSD service and preventing it from starting automatically on system boot. However, disabling NFSD may impact the functionality of NFS services on the affected system.
Conclusion
The NFSD READDIR buffer overflow vulnerability in the Linux Kernel can be mitigated by updating to version v5.15.12 or later. Users can also consider disabling the NFSD component as a temporary workaround. For further support and assistance in vulnerability remediation, please contact DevNack.com.
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FAQ
NFSD is the Network File System (NFS) server daemon in the Linux Kernel. It handles NFS requests on the server side, allowing remote access to files over a network.
A buffer overflow is a vulnerability that occurs when a program writes data beyond the boundaries of a fixed-size buffer. This can lead to memory corruption and potentially allow an attacker to execute arbitrary code or crash the program.
This vulnerability in NFSD can potentially allow an attacker to execute arbitrary code or cause a denial-of-service condition on the affected system.
You can use tools like Vulert (https://vulert.com) to check if your system is affected by this vulnerability. Vulert uses a manifest file like package-lock.json to monitor and alert in real-time for open-source vulnerabilities in the software.
Yes, as a temporary workaround, you can disable the NFSD component if it is not required for your system. However, this may impact the functionality of NFS services on the affected system.
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