From f35d12971b4d814cdb2f659d76b42f0c545270b6 Mon Sep 17 00:00:00 2001 From: Xiyu Yang Date: Thu, 23 Apr 2020 13:13:03 +0800 Subject: net/x25: Fix x25_neigh refcnt leak when receiving frame 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 Signed-off-by: Xin Tan Signed-off-by: David S. Miller --- 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]) { -- cgit v1.2.3-59-g8ed1b