From 6f91a3f7af4186099dd10fa530dd7e0d9c29747d Mon Sep 17 00:00:00 2001
From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Date: Mon, 20 Apr 2020 13:37:20 +0800
Subject: [PATCH] batman-adv: Fix refcnt leak in batadv_v_ogm_process
Git-commit: 6f91a3f7af4186099dd10fa530dd7e0d9c29747d
Patch-mainline: v5.7-rc5
References: git-fixes

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: 9323158ef9f4 ("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>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/batman-adv/bat_v_ogm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index 969466218999..80b87b1f4e3a 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -893,7 +893,7 @@ static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 
 	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);
-- 
2.16.4