CVE-2022-48961 Information

Description

In the Linux kernel the following vulnerability has been resolved:

net: mdio: fix unbalanced fwnode reference count in mdio_device_release()

There is warning report about of_node refcount leak while probing mdio device:

OF: ERROR: memory leak expected refcount 1 instead of 2 of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node /spi/soc@0/mdio@710700c0/ethernet@4

In of_mdiobus_register_device() we increase fwnode refcount by fwnode_handle_get() before associating the of_node with mdio device but it has never been decreased in normal path. Since that in mdio_device_release() it needs to call fwnode_handle_put() in addition instead of calling kfree() directly.

After above just calling mdio_device_free() in the error handle path of of_mdiobus_register_device() is enough to keep the refcount balanced.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

https://git.kernel.org/stable/c/16854177745a5648f8ec322353b432e18460f43a https://git.kernel.org/stable/c/a5c6de1a6656b8cc6bce7cb3d9874dd7df4968c3 https://git.kernel.org/stable/c/cb37617687f2bfa5b675df7779f869147c9002bd

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5