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Commit ef72706a authored by Marek Lindner's avatar Marek Lindner Committed by Antonio Quartulli
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batman-adv: protect tt_local_entry from concurrent delete events 



The tt_local_entry deletion performed in batadv_tt_local_remove() was neither
protecting against simultaneous deletes nor checking whether the element was
still part of the list before calling hlist_del_rcu().

Replacing the hlist_del_rcu() call with batadv_hash_remove() provides adequate
protection via hash spinlocks as well as an is-element-still-in-hash check to
avoid 'blind' hash removal.

Fixes: 068ee6e2 ("batman-adv: roaming handling mechanism redesign")
Reported-by: default avatar <alfonsname@web.de>
Signed-off-by: default avatarMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: default avatarAntonio Quartulli <antonio@meshcoding.com>
parent 354136bc

net/batman-adv/translation-table.c

+10 −1
Original line number Diff line number Diff line
@@ -1037,6 +1037,7 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv, 
	struct batadv_tt_local_entry *tt_local_entry;

	uint16_t flags, curr_flags = BATADV_NO_FLAGS;

	struct batadv_softif_vlan *vlan;

	void *tt_entry_exists;



	tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid);

	if (!tt_local_entry)
@@ -1064,7 +1065,15 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv, 
	 * immediately purge it

	 */

	batadv_tt_local_event(bat_priv, tt_local_entry, BATADV_TT_CLIENT_DEL);

	hlist_del_rcu(&tt_local_entry->common.hash_entry);



	tt_entry_exists = batadv_hash_remove(bat_priv->tt.local_hash,

					     batadv_compare_tt,

					     batadv_choose_tt,

					     &tt_local_entry->common);

	if (!tt_entry_exists)

		goto out;



	/* extra call to free the local tt entry */

	batadv_tt_local_entry_free_ref(tt_local_entry);



	/* decrease the reference held for this vlan */