CVE-2022-48867

/// Technical description

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

dmaengine: idxd: Prevent use after free on completion memory

On driver unload any pending descriptors are flushed at the

time the interrupt is freed:

idxd_dmaengine_drv_remove() ->

drv_disable_wq() ->

idxd_wq_free_irq() ->

idxd_flush_pending_descs().

If there are any descriptors present that need to be flushed this

flow triggers a "not present" page fault as below:

BUG: unable to handle page fault for address: ff391c97c70c9040

#PF: supervisor read access in kernel mode

#PF: error_code(0x0000) - not-present page

The address that triggers the fault is the address of the

descriptor that was freed moments earlier via:

drv_disable_wq()->idxd_wq_free_resources()

Fix the use after free by freeing the descriptors after any possible

usage. This is done after idxd_wq_reset() to ensure that the memory

remains accessible during possible completion writes by the device.

/// 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