Linux Kernel WiFi Libertas Driver USB Transmission Warning Fix

A vulnerability in the Linux kernel's WiFi Libertas driver has been addressed. The issue arose in the 'usb_tx_block()' function, which submitted a USB transfer request without confirming that any prior transmission had finished. This could lead to a warning being triggered if a new request was sent while the previous one was still active, such as during fast firmware updates. The vulnerability has been fixed by ensuring that the USB transfer request is completed before a new one is submitted, preventing the warning from occurring.

Impact

The vulnerability could cause a warning to be issued during USB transmissions, indicating that a transfer was attempted while a previous one was still active. This could disrupt the normal operation of the WiFi Libertas driver, particularly during rapid firmware updates.

Reproduction

The vulnerability can be reproduced by calling the 'usb_tx_block()' function with a payload while the previous transmission on the USB request is still active. This can occur during fast firmware loading, where the driver attempts to send multiple USB transfer requests before the first one has completed. The 'usb_submit_urb()' function will then detect the active state of the USB request and trigger a warning, indicating that a new request was submitted while the previous one was still in progress.

Remediation

Users can update to the latest version of the Linux kernel, where this vulnerability has been fixed. Instructions for downloading the updated kernel can be found on the official Linux kernel website.