CVE-2022-48953

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

rtc: cmos: Fix event handler registration ordering issue

Because acpi_install_fixed_event_handler() enables the event

automatically on success, it is incorrect to call it before the

handler routine passed to it is ready to handle events.

Unfortunately, the rtc-cmos driver does exactly the incorrect thing

by calling cmos_wake_setup(), which passes rtc_handler() to

acpi_install_fixed_event_handler(), before cmos_do_probe(), because

rtc_handler() uses dev_get_drvdata() to get to the cmos object

pointer and the driver data pointer is only populated in

cmos_do_probe().

This leads to a NULL pointer dereference in rtc_handler() on boot

if the RTC fixed event happens to be active at the init time.

To address this issue, change the initialization ordering of the

driver so that cmos_wake_setup() is always called after a successful

cmos_do_probe() call.

While at it, change cmos_pnp_probe() to call cmos_do_probe() after

the

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References