CVE-2024-26867

/// Technical description

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

comedi: comedi_8255: Correct error in subdevice initialization

The refactoring done in commit 5c57b1ccecc7 ("comedi: comedi_8255: Rework

subdevice initialization functions") to the initialization of the io

field of struct subdev_8255_private broke all cards using the

drivers/comedi/drivers/comedi_8255.c module.

Prior to 5c57b1ccecc7, __subdev_8255_init() initialized the io field

in the newly allocated struct subdev_8255_private to the non-NULL

callback given to the function, otherwise it used a flag parameter to

select between subdev_8255_mmio and subdev_8255_io. The refactoring

removed that logic and the flag, as subdev_8255_mm_init() and

subdev_8255_io_init() now explicitly pass subdev_8255_mmio and

subdev_8255_io respectively to __subdev_8255_init(), only

__subdev_8255_init() never sets spriv->io to the supplied

callback. That spriv->io is NULL leads to a later BUG:

BUG: kernel NULL pointer dereference, address:

/// 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