From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Date: Mon, 20 Apr 2020 13:37:20 +0800
Subject: batman-adv: Fix refcnt leak in batadv_v_ogm_process

batadv_v_ogm_process() invokes batadv_hardif_neigh_get(), which returns
a reference of the neighbor object to "hardif_neigh" with increased
refcount.

When batadv_v_ogm_process() returns, "hardif_neigh" becomes invalid, so
the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling paths of
batadv_v_ogm_process(). When batadv_v_ogm_orig_get() fails to get the
orig node and returns NULL, the refcnt increased by
batadv_hardif_neigh_get() is not decreased, causing a refcnt leak.

Fix this issue by jumping to "out" label when batadv_v_ogm_orig_get()
fails to get the orig node.

Fixes: 667996ebeab4 ("batman-adv: OGMv2 - implement originators logic")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>

Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/4515f5e6a4ccbe1c563b05f2d487eb9eef3c9740

--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -723,7 +723,7 @@ static void batadv_v_ogm_process(const s
 
 	orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 	if (!orig_node)
-		return;
+		goto out;
 
 	neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 						     ethhdr->h_source);