Commit 33623b4e authored by Sven Eckelmann's avatar Sven Eckelmann Committed by Kelsey Skunberg

batman-adv: Prevent duplicated tvlv handler

BugLink: https://bugs.launchpad.net/bugs/1868629

commit ae3cdc97 upstream.

The function batadv_tvlv_handler_register is responsible for adding new
tvlv_handler to the handler_list. It first checks whether the entry
already is in the list or not. If it is, then the creation of a new entry
is aborted.

But the lock for the list is only held when the list is really modified.
This could lead to duplicated entries because another context could create
an entry with the same key between the check and the list manipulation.

The check and the manipulation of the list must therefore be in the same
locked code section.

Fixes: ef261577 ("batman-adv: tvlv - basic infrastructure")
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarKhalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: default avatarKelsey Skunberg <kelsey.skunberg@canonical.com>
parent dd1f7814
......@@ -1079,15 +1079,20 @@ void batadv_tvlv_handler_register(struct batadv_priv *bat_priv,
{
struct batadv_tvlv_handler *tvlv_handler;
spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version);
if (tvlv_handler) {
spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
batadv_tvlv_handler_free_ref(tvlv_handler);
return;
}
tvlv_handler = kzalloc(sizeof(*tvlv_handler), GFP_ATOMIC);
if (!tvlv_handler)
if (!tvlv_handler) {
spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
return;
}
tvlv_handler->ogm_handler = optr;
tvlv_handler->unicast_handler = uptr;
......@@ -1097,7 +1102,6 @@ void batadv_tvlv_handler_register(struct batadv_priv *bat_priv,
atomic_set(&tvlv_handler->refcount, 1);
INIT_HLIST_NODE(&tvlv_handler->list);
spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
hlist_add_head_rcu(&tvlv_handler->list, &bat_priv->tvlv.handler_list);
spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
}
......
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