Vulnerability in Kernel: Staging: Greybus: UART: Fix TTY Use After Free
Summary
GSD-2021-1001767: staging: greybus: uart: fix tty use after free. Affects Kernel versions >= a18e15175708d39abbe9746ddc3479466b7800c3, < 9872ff6fdce8b229f01993b611b5d1719cb70ff1. 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 functionalities and acts as an interface between hardware and software. It manages system resources, facilitates communication between different software components, and ensures the overall stability and security of the system. The Staging subsystem in the Kernel is responsible for hosting experimental or incomplete drivers that are not yet ready for mainstream integration. Greybus is one such driver framework that enables communication between various subsystems in the system. The UART (Universal Asynchronous Receiver-Transmitter) driver within the Greybus staging subsystem handles serial communication. However, a vulnerability has been identified in this driver that can lead to a use-after-free condition in the TTY (teletypewriter) subsystem.
Vulnerability Detail
The vulnerability in the Greybus UART driver allows an attacker to exploit a use-after-free condition in the TTY subsystem. This occurs when the driver continues to reference a TTY object after it has been freed from memory. By manipulating this vulnerability, an attacker may be able to execute arbitrary code or cause a denial-of-service condition, potentially compromising the integrity and availability of the system. The vulnerability was introduced in version 4.9 of the Linux Kernel and has been fixed in version 5.14.9.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can disable or unload the Greybus UART driver if it is not essential for their system's operation. This can be done by executing the following commands:
modprobe -r greybus_uart
Conclusion
The vulnerability in the Greybus UART driver of the Linux Kernel can lead to a use-after-free condition in the TTY subsystem, potentially allowing an attacker to execute arbitrary code or cause a denial-of-service condition. It is crucial to update the Kernel to version 5.14.9 or later to mitigate this vulnerability. Alternatively, users can disable or unload the Greybus UART driver if it is not necessary for their system's operation. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
The vulnerability can potentially allow an attacker to execute arbitrary code or cause a denial-of-service condition, compromising the integrity and availability of the system.
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 and the Vulert Playground will analyze it for any open-source vulnerabilities, including this one.
Yes, the vulnerability has been fixed in version 5.14.9 of the Linux Kernel. It is recommended to update to this version or a later one to mitigate the vulnerability.
Yes, as a temporary measure, you can disable or unload the Greybus UART driver if it is not necessary for your system's operation. Refer to the 'workaround' section for instructions on how to do this.
You can find more information about this vulnerability, including the specific commits that introduced and fixed it, in the Open Source Vulnerability Database (OSV) entry: https://github.com/cloudsecurityalliance/gsd-database/blob/main/2021/1001xxx/GSD-2021-1001767.json
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