[PATCH] batman-adv: Fix refcnt leak in batadv_v_ogm_process

[PATCH] batman-adv: Fix refcnt leak in batadv_v_ogm_process

[Xiyu Yang]

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>
---
 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);
-- 
2.7.4

Re: [PATCH] batman-adv: Fix refcnt leak in batadv_v_ogm_process

[Sven Eckelmann]

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On Monday, 20 April 2020 07:37:20 CEST Xiyu Yang wrote:
> 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>
> ---
>  net/batman-adv/bat_v_ogm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied [1]

Thanks,
	Sven

[1] https://git.open-mesh.org/linux-merge.git/commit/afba933d9875cdf31c973a1ecf05de7129a142c4

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