Linux Kernel IT6505 AUX Channel Initialization Vulnerability Causes NULL Pointer Dereference

A vulnerability in the Linux kernel's IT6505 driver can lead to a NULL pointer dereference. This issue occurs when the Hot Plug Detect (HPD) interrupt is triggered before the Display Room (DRM) subsystem has registered the IT6505 as a DRM bridge. As a result, the driver attempts to access the AUX channel, causing a NULL pointer dereference. The vulnerability affects several versions of the Linux kernel.

Impact

The vulnerability can cause a system crash due to a NULL pointer dereference, disrupting normal operations and potentially leading to a denial of service.

Reproduction

The vulnerability can be reproduced by triggering the HPD interrupt before the IT6505 driver is registered as a DRM bridge. This can occur during the device boot process, leading to a NULL pointer dereference when the driver tries to access the AUX channel.

Remediation

The vulnerability has been addressed by modifying the IT6505 driver to initialize the AUX channel earlier in the device boot process. Users should update to the latest version of the Linux kernel where this fix has been applied.