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authorSven Eckelmann <sven@narfation.org>2016-08-06 15:50:52 +0200
committerSimon Wunderlich <sw@simonwunderlich.de>2016-08-26 15:22:30 +0200
commit936523441bb64cdc9a5b263e8fd2782e70313a57 (patch)
treedcc21b6097509844be06b692a15f6c3f0128497f
parent1fe323aa1b2390a0c57fb0b06a782f128d49094c (diff)
batman-adv: Add missing refcnt for last_candidate
batadv_find_router dereferences last_bonding_candidate from orig_node without making sure that it has a valid reference. This reference has to be retrieved by increasing the reference counter while holding neigh_list_lock. The lock is required to avoid that batadv_last_bonding_replace removes the current last_bonding_candidate, reduces the reference counter and maybe destroys the object in this process. Fixes: f3b3d9018975 ("batman-adv: add bonding again") Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
-rw-r--r--net/batman-adv/routing.c28
1 files changed, 27 insertions, 1 deletions
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 7602c001e92b..3d199478c405 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -470,6 +470,29 @@ static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
}
/**
+ * batadv_last_bonding_get - Get last_bonding_candidate of orig_node
+ * @orig_node: originator node whose last bonding candidate should be retrieved
+ *
+ * Return: last bonding candidate of router or NULL if not found
+ *
+ * The object is returned with refcounter increased by 1.
+ */
+static struct batadv_orig_ifinfo *
+batadv_last_bonding_get(struct batadv_orig_node *orig_node)
+{
+ struct batadv_orig_ifinfo *last_bonding_candidate;
+
+ spin_lock_bh(&orig_node->neigh_list_lock);
+ last_bonding_candidate = orig_node->last_bonding_candidate;
+
+ if (last_bonding_candidate)
+ kref_get(&last_bonding_candidate->refcount);
+ spin_unlock_bh(&orig_node->neigh_list_lock);
+
+ return last_bonding_candidate;
+}
+
+/**
* batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
* @orig_node: originator node whose bonding candidates should be replaced
* @new_candidate: new bonding candidate or NULL
@@ -539,7 +562,7 @@ batadv_find_router(struct batadv_priv *bat_priv,
* router - obviously there are no other candidates.
*/
rcu_read_lock();
- last_candidate = orig_node->last_bonding_candidate;
+ last_candidate = batadv_last_bonding_get(orig_node);
if (last_candidate)
last_cand_router = rcu_dereference(last_candidate->router);
@@ -631,6 +654,9 @@ next:
batadv_orig_ifinfo_put(next_candidate);
}
+ if (last_candidate)
+ batadv_orig_ifinfo_put(last_candidate);
+
return router;
}