CVE-2022-48812

/// Technical description

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

net: dsa: lantiq_gswip: don't use devres for mdiobus

As explained in commits:

74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres")

5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres")

mdiobus_free() will panic when called from devm_mdiobus_free() <-

devres_release_all() <- __device_release_driver(), and that mdiobus was

not previously unregistered.

The GSWIP switch is a platform device, so the initial set of constraints

that I thought would cause this (I2C or SPI buses which call ->remove on

->shutdown) do not apply. But there is one more which applies here.

If the DSA master itself is on a bus that calls ->remove from ->shutdown

(like dpaa2-eth, which is on the fsl-mc bus), there is a device link

between the switch and the DSA master, and device_links_unbind_consumers()

will unbind the GSWIP switch driver on shutdown.

So the same treatment must be applied to all DSA switch d

/// 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