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Subject[PATCH] net/x25: Fix x25_neigh refcnt leak when reveiving frame
Date
x25_lapb_receive_frame() invokes x25_get_neigh(), which returns a
reference of the specified x25_neigh object to "nb" with increased
refcnt.

When x25_lapb_receive_frame() returns, local variable "nb" becomes
invalid, so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one path of
x25_lapb_receive_frame(). When pskb_may_pull() returns false, the
function forgets to decrease the refcnt increased by x25_get_neigh(),
causing a refcnt leak.

Fix this issue by calling x25_neigh_put() when pskb_may_pull() returns
false.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
net/x25/x25_dev.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/x25/x25_dev.c b/net/x25/x25_dev.c
index 00e782335cb0..25bf72ee6cad 100644
--- a/net/x25/x25_dev.c
+++ b/net/x25/x25_dev.c
@@ -115,8 +115,10 @@ int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev,
goto drop;
}

- if (!pskb_may_pull(skb, 1))
+ if (!pskb_may_pull(skb, 1)) {
+ x25_neigh_put(nb);
return 0;
+ }

switch (skb->data[0]) {

--
2.7.4
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