[B.A.T.M.A.N.] [PATCHv2 maint] batman-adv: increase orig refcount when storing ref in gw_node

[B.A.T.M.A.N.] [PATCHv2 maint] batman-adv: increase orig refcount when storing ref in gw_node

[Antonio Quartulli]

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

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>
---

Change since v1:
- properly release orig_node in case of gw_node allocation failure

 gateway_client.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/gateway_client.c b/gateway_client.c
index d7fafc1..d5a40ab 100644
--- a/gateway_client.c
+++ b/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 *
@@ -406,9 +408,14 @@ static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 	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;
-- 
1.8.3.2

Re: [B.A.T.M.A.N.] [PATCHv2 maint] batman-adv: increase orig refcount when storing ref in gw_node

[Marek Lindner]

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On Friday 02 May 2014 01:35:13 Antonio Quartulli wrote:
> From: Antonio Quartulli <antonio@open-mesh.com>
> 
> 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>
> ---
> 
> Change since v1:
> - properly release orig_node in case of gw_node allocation failure
> 
>  gateway_client.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)

Applied in revision 8dbdee5.

Thanks,
Marek

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