CVE-2022-49290

/// Technical description

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

mac80211: fix potential double free on mesh join

While commit 6a01afcf8468 ("mac80211: mesh: Free ie data when leaving

mesh") fixed a memory leak on mesh leave / teardown it introduced a

potential memory corruption caused by a double free when rejoining the

mesh:

ieee80211_leave_mesh()

-> kfree(sdata->u.mesh.ie);

...

ieee80211_join_mesh()

-> copy_mesh_setup()

-> old_ie = ifmsh->ie;

-> kfree(old_ie);

This double free / kernel panics can be reproduced by using wpa_supplicant

with an encrypted mesh (if set up without encryption via "iw" then

ifmsh->ie is always NULL, which avoids this issue). And then calling:

$ iw dev mesh0 mesh leave

$ iw dev mesh0 mesh join my-mesh

Note that typically these commands are not used / working when using

wpa_supplicant. And it seems that wpa_supplicant or wpa_cli are going

through a NETDEV_DOWN/NETDEV_UP cycle between a mesh leave and mesh join

where the NETDEV

/// 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