USB Gadget f_fs Vulnerability in Linux Kernel
Summary
GSD-2022-1000014: usb: gadget: f_fs: Clear ffs_eventfd in ffs_data_clear. Affects Kernel versions >= 5e33f6fdf735cda1d4580fe6f1878da05718fe73, < cc8c8028c21b2a3842a1e98e99e55028df275919. No fix is published. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
The Linux Kernel is the core component of the Linux operating system, responsible for managing system resources and providing an interface for applications to interact with the hardware. The USB gadget subsystem in the Linux Kernel allows the system to act as a USB device, enabling functionalities such as USB tethering and USB Mass Storage. The f_fs module within the USB gadget subsystem is responsible for implementing the Function File System (FFS) protocol. FFS provides a way to expose files and directories on the USB device. However, a vulnerability has been discovered in the f_fs module that could potentially be exploited by an attacker.
Vulnerability Detail
The vulnerability in the f_fs module of the USB gadget subsystem arises from a failure to clear the ffs_eventfd variable in the ffs_data_clear function. This oversight could allow an attacker to manipulate the ffs_eventfd value, leading to various security issues. The exact impact and attack vectors are yet to be proven, but potential consequences may include privilege escalation, denial of service, or information disclosure. The vulnerability was introduced in version 4.0 of the Linux Kernel and has been fixed in version 4.9.296.
How To Fix
No fixed version is published for this vulnerability.
Tip — Not sure whether your app is affected? Vulert can check the versions your app actually runs. Scan free →
Workaround
As a temporary workaround, you can disable the f_fs module by removing it from the kernel configuration and rebuilding the kernel. However, this may disable any functionality relying on the USB gadget subsystem's f_fs module.
Conclusion
The USB Gadget f_fs vulnerability in the Linux Kernel's USB gadget subsystem could potentially be exploited by attackers to gain privileges, cause denial of service, or disclose sensitive information. It is crucial to update the Linux Kernel to version 4.9.296 or later to mitigate this vulnerability. If you require further assistance or support in addressing this vulnerability, please contact DevNack.com.
See every vulnerability recorded for Kernel →
FAQ
The USB gadget subsystem in the Linux Kernel allows the system to act as a USB device, enabling functionalities such as USB tethering and USB Mass Storage.
The f_fs module is a part of the USB gadget subsystem and is responsible for implementing the Function File System (FFS) protocol, which provides a way to expose files and directories on the USB device.
The exact impact of this vulnerability is yet to be proven, but it could potentially lead to privilege escalation, denial of service, or information disclosure.
To fix this vulnerability, it is recommended to update the Linux Kernel to version 4.9.296 or later.
Yes, you can temporarily disable the f_fs module by removing it from the kernel configuration and rebuilding the kernel.
Related vulnerabilities
Recent vulnerabilities recorded for Kernel.
