CVE-2022-49812

/// Technical description

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

bridge: switchdev: Fix memory leaks when changing VLAN protocol

The bridge driver can offload VLANs to the underlying hardware either

via switchdev or the 8021q driver. When the former is used, the VLAN is

marked in the bridge driver with the 'BR_VLFLAG_ADDED_BY_SWITCHDEV'

private flag.

To avoid the memory leaks mentioned in the cited commit, the bridge

driver will try to delete a VLAN via the 8021q driver if the VLAN is not

marked with the previously mentioned flag.

When the VLAN protocol of the bridge changes, switchdev drivers are

notified via the 'SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL' attribute, but

the 8021q driver is also called to add the existing VLANs with the new

protocol and delete them with the old protocol.

In case the VLANs were offloaded via switchdev, the above behavior is

both redundant and buggy. Redundant because the VLANs are already

programmed in hardware and drivers that support VLAN protoc

/// 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