[PATCH 1/2] batman-adv: Add missing refcnt for last_candidate
DORMANTno replies
From: Simon Wunderlich <hidden>
Date: 2016-09-14 12:37:34
Also in:
batman
Subsystem:
batman advanced, the rest · Maintainers:
Marek Lindner, Simon Wunderlich, Antonio Quartulli, Sven Eckelmann, Linus Torvalds
From: Sven Eckelmann <redacted>
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 <redacted>
Signed-off-by: Marek Lindner <redacted>
Signed-off-by: Simon Wunderlich <redacted>
---
net/batman-adv/routing.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 7602c00..3d19947 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; }
--
2.9.3