Hello LinuxPatch readers! Today, we're delving into a recently-disclosed cybersecurity issue that affects Linux systems, specifically those utilizing the 'iwlwifi' driver. This medium severity issue, numbered CVE-2024-53055, scores 5.5 out of 10 on the CVE scale, indicating significant impacts that warrant attention.
CVE-2024-53055 addresses a critical flaw in the construction of 6 GHz scans by the 'iwlwifi' driver's 'mvm' module in the Linux kernel. Before we delve into the specifics of the fix, let's understand a bit more about the software and its functionality.
The 'iwlwifi' driver is a crucial component for Linux systems, handling wireless device operations and communications. Its module 'mvm' (Medium Vector Manager) specifically deals with managing aspects of the wireless medium. This flaw directly interferes with the driver's ability to perform wireless scanning at 6 GHz, a capability vital for ensuring the device can communicate effectively in a congested wireless environment.
The issue arises when a Linux device equipped with this driver attempts to perform a wireless scan. In networks where there are more than 255 Access Points (APs) operating in proximity at 2.4 or 5 GHz frequencies, the scanning mechanism for 6 GHz bands malfunctions. Let's break down the problem: When the system scans for APs, it collects and counts the number of adjacent APs during a 2.4/5 GHz scan. However, due to a typecast issue in the original code, where a 8-bit unsigned integer (u8) was used for counting, it could not handle numbers over 255. Consequently, if the number of APs exceeded 255, the scan construction looped indefinitely as it was unable to reach the actual count stored in a 32-bit unsigned integer (u32).
Identifying such a loop can cause a serious performance drag, potentially freezing the system or causing it to operate inefficiently. In response to this, Linux kernel developers released a patch wherein the loop variable has now been changed to a 32-bit unsigned integer (u32) to handle a much larger range of numbers – up to 372,000 theoretically. This aligns with the frame size limits and the maximum number of scan results capped at 1000, ensuring that the integer overflow and indefinite looping is prevented.
This update is crucial for the stability and efficiency of Linux systems operating in environments with a dense number of Wi-Fi networks. By fixing this flaw, the kernel ensures better handling of WiFi scanning, particularly in newer 6 GHz bands, which are integral for next-generation WiFi 6E technologies that promise faster speeds and more reliable wireless connections.
For all LinuxPatch customers, it's essential to apply this update immediately if your systems use the iwlwifi driver. Delaying this update can expose your system to unnecessary risks, particularly in environments with extensive WiFi usage. Regular updates to your system and informed cybersecurity practices are the best defenses against potential vulnerabilities.
Stay tuned to LinuxPatch for more updates and deep dives into the world of Linux cybersecurity. Protecting your systems is our top priority, and keeping you informed is part of how we help you stay secure. Thank you for trusting us with the security of your Linux environments!