Linux Kernel NFC NCI UART TTY Data Handling Vulnerability

A vulnerability in the Linux kernel's NFC subsystem, specifically within the NCI UART implementation, has been addressed. The issue arose because the tty->disc_data was set before the NCI device was fully opened, creating a potential error condition. This premature assignment could lead to data being sent from the device before the NCIUARTSETDRIVER IOCTL had successfully completed, possibly due to faulty hardware. The vulnerability has been resolved by ensuring that tty->disc_data is only assigned after the NCI device has been successfully opened and the module has been properly loaded. This change prevents the introduction of a timing window where data could be incorrectly transmitted.

Impact

Exploitation of this vulnerability could lead to improper handling of UART data, potentially allowing for erroneous data transmission before the NCI device is fully initialized.