[PATCH 3.14 134/140] batman-adv: increase orig refcount when storing ref in gw_node

Greg Kroah-Hartman
2014-05-29T04:36:07Z

From: Antonio Quartulli <antonio@open-mesh.com>

[ Upstream commit 377fe0f968b30a1a714fab53a908061914f30e26 ]

A pointer to the orig_node representing a bat-gateway is
stored in the gw_node->orig_node member, but the refcount
for such orig_node is never increased.
This leads to memory faults when gw_node->orig_node is accessed
and the originator has already been freed.

Fix this by increasing the refcount on gw_node creation
and decreasing it on gw_node free.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/batman-adv/gateway_client.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -42,8 +42,10 @@

static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
{
- if (atomic_dec_and_test(&gw_node->refcount))
+ if (atomic_dec_and_test(&gw_node->refcount)) {
+ batadv_orig_node_free_ref(gw_node->orig_node);
kfree_rcu(gw_node, rcu);
+ }
}

static struct batadv_gw_node *
@@ -408,9 +410,14 @@ static void batadv_gw_node_add(struct ba
if (gateway->bandwidth_down == 0)
return;

+ if (!atomic_inc_not_zero(&orig_node->refcount))
+ return;
+
gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
- if (!gw_node)
+ if (!gw_node) {
+ batadv_orig_node_free_ref(orig_node);
return;
+ }

INIT_HLIST_NODE(&gw_node->list);
gw_node->orig_node = orig_node;