CVE-2022-49539

/// Technical description

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

rtw89: ser: fix CAM leaks occurring in L2 reset

The CAM, meaning address CAM and bssid CAM here, will get leaks during

SER (system error recover) L2 reset process and ieee80211_restart_hw()

which is called by L2 reset process eventually.

The normal flow would be like

-> add interface (acquire 1)

-> enter ips (release 1)

-> leave ips (acquire 1)

-> connection (occupy 1) <(A) 1 leak after L2 reset if non-sec connection>

The ieee80211_restart_hw() flow (under connection)

-> ieee80211 reconfig

-> add interface (acquire 1)

-> leave ips (acquire 1)

-> connection (occupy (A) + 2) <(B) 1 more leak>

Originally, CAM is released before HW restart only if connection is under

security. Now, release CAM whatever connection it is to fix leak in (A).

OTOH, check if CAM is already valid to avoid acquiring multiple times to

fix (B).

Besides, if AP mode, release address CAM of all stations before HW restart.

/// 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