In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: fix mesh fast xmit path deletion UAF mesh_fast_tx_cach

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

wifi: mac80211: fix mesh fast xmit path deletion UAF

mesh_fast_tx_cache() stores raw mesh_path pointers. Path deletion
flushes the cache and then frees the path with kfree_rcu(), but a
lookup that already holds the path can insert a new cache entry
after the flush. The cache then points at freed memory.

Set MESH_PATH_DELETED before flushing, and skip inserting a cache
entry if the path or MPP path is already deleted. Check this under
the cache walk lock so it is ordered with the flush. Use WRITE_ONCE()
for the deletion flag updates because the cache check reads flags
without taking state_lock.