Affected: Linux

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

wifi: mac80211: account proxy paths against the mesh path limit

Proxy-path churn can drive the interface path counter negative and let later mesh path additions exceed MESH_MAX_MPATHS.

mesh_path_free_rcu() decrements the interface mpaths counter for entries from both the mesh and proxy path tables, but mpp_path_add() never reserves a slot in that counter. Removing or expiring a proxy path therefore returns a slot that was never charged.

mesh_path_add() uses the same counter to enforce MESH_MAX_MPATHS, so once it falls below the number of installed paths the limit no longer holds.

Reserve the shared quota before allocating a proxy path and release it on every unsuccessful addition. Mesh and proxy paths now share one 1024-entry budget, so mpp_path_add() can return -ENOSPC at that limit.