From: Xiyu Yang xiyuyang19@fudan.edu.cn
[ Upstream commit f35d12971b4d814cdb2f659d76b42f0c545270b6 ]
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.
Fixes: cb101ed2c3c7 ("x25: Handle undersized/fragmented skbs") Signed-off-by: Xiyu Yang xiyuyang19@fudan.edu.cn Signed-off-by: Xin Tan tanxin.ctf@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 1763e198..ef0dca8 100644 --- a/net/x25/x25_dev.c +++ b/net/x25/x25_dev.c @@ -120,8 +120,10 @@ 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]) {