Welcome to our comprehensive overview of a recent medium-severity security issue that impacts the Linux kernel, specifically within the functionality of its Wi-Fi firmware. Today, we'll be breaking down the nuances of CVE-2024-46827 to better understand its implications and the corrective measures taken.
CVE-2024-46827 is a notable vulnerability identified in the ath12k Wi-Fi driver of the Linux kernel. This flaw centers around how the firmware handles specific types of corrupted data it receives, which, in this case, is an invalid peer_nss (Number of Spatial Streams) value within the Extended HE (High Efficiency) Capabilities Information Element. The severity of this issue has been rated as 'MEDIUM' with a score of 5.5, indicating a significant risk that requires attention but isn't critically urgent.
The Linux kernel, the core interface between a computer's hardware and its software, provides a vast range of functionalities through its modules, including managing hardware devices like Wi-Fi adapters. The ath12k driver, part of this kernel, facilitates communication between the operating system and specific Qualcomm Atheros Wi-Fi hardware. This driver ensures that the Linux system can connect to Wi-Fi networks efficiently and manage wireless data transmission reliably.
When an access point using the ath12k driver receives an association request that includes an Extended HE Capabilities Information Element with a defined MCS-NSS, where the MCS-NSS set bandwidth is zero-filled, it leads to an improper calculation of the peer_nss. Essentially, the driver mistakenly retrieves a zero value for peer_nss, and passing this zero value to the firmware results in a crash. This particular scenario can disrupt Wi-Fi service and potentially compromise the stability and security of the Linux system.
The primary impact involves potential service interruptions and system instability for devices using the affected Linux kernels, especially in environments where reliability and continuous connectivity are critical, such as in business or large-scale network settings. The crash can lead to sporadic disconnects, reduced network efficiency, and increased administrative overhead due to system recovery and troubleshooting efforts.
To tackle CVE-2024-46827, a solution has been implemented directly in the Linux kernel's ath12k driver. The fix includes adding a validation step before passing the peer_nss value to the firmware. Now, if the peer_nss value is detected to be greater than zero, the driver forwards it appropriately. However, if the value is zero (indicative of the vulnerability being exploited), the driver will reject the association request. This prevents the corrupted data from reaching the firmware and causing a system crash. This fix not only resolves the immediate issue but also enhances the overall robustness of the Wi-Fi driver against similar data corruption scenarios in the future.
For users and administrators of Linux systems, understanding and applying updates related to CVE-2024-46827 is crucial for maintaining system stability and security. This resolution not only addresses the immediate bug but also improves the resilience of your system against future vulnerabilities. We encourage all affected users to update their systems as soon as possible to mitigate the risks associated with this vulnerability.