Linux Kernel Realtek RTW89 Wireless Driver NAPI Race Condition Vulnerability

A race condition vulnerability has been identified in the Linux kernel's Realtek RTW89 wireless driver. This issue arises when a network device (netdev) is registered before the NAPI (New API) is fully initialized. If user space activates the netdev during this window, it can lead to a kernel panic, triggered by the NAPI enabling process. The vulnerability has been observed in Linux kernel version 6.2.7.

Impact

Exploitation of this vulnerability causes a kernel panic, disrupting system operations and potentially leading to a denial of service.

Reproduction

The vulnerability can be reproduced by registering a network device without initializing the NAPI, then activating the netdev from user space. This sequence triggers a kernel bug due to the NAPI not being ready, causing a crash.

Remediation

The vulnerability has been addressed by reordering the initialization process, ensuring that the netdev is registered only after the NAPI is fully set up. Users should update to the latest version of the Linux kernel where this fix has been applied.