esp_event_is_handler_registered() walked loop_nodes, base_nodes, id_nodes
and handler lists with no lock held, then released an unowned mutex at the
'out:' label via xSemaphoreGive().
Concurrent register/unregister/delete operations can free handler nodes
during the unlocked walk (SLIST UAF). The xSemaphoreGive on an unowned
recursive mutex corrupts the recursive call-count of any task that
legitimately holds the mutex.
Fix:
- Take loop->mutex with xSemaphoreTakeRecursive before the traversal.
- Replace xSemaphoreGive at the 'out:' label with xSemaphoreGiveRecursive
so every exit path holds the mutex for exactly one balanced take/give.
Closes SEC_219
Some files that should have their copyrights checked are still placed on the
copyright ignore list.
- These entries have been tidied up
- Copyrights of those files have been updated.