[PATCH 5.4 025/102] tipc: fix potential memory leak in __tipc_sendmsg()

[Greg Kroah-Hartman]

From: Tung Nguyen <tung.q.nguyen@xxxxxxxxxxxxxx>

commit 2fe97a578d7bad3116a89dc8a6692a51e6fc1d9c upstream.

When initiating a connection message to a server side, the connection
message is cloned and added to the socket write queue. However, if the
cloning is failed, only the socket write queue is purged. It causes
memory leak because the original connection message is not freed.

This commit fixes it by purging the list of connection message when
it cannot be cloned.

Fixes: 6787927475e5 ("tipc: buffer overflow handling in listener socket")
Reported-by: Hoang Le <hoang.h.le@xxxxxxxxxxxxxx>
Signed-off-by: Tung Nguyen <tung.q.nguyen@xxxxxxxxxxxxxx>
Acked-by: Ying Xue <ying.xue@xxxxxxxxxxxxx>
Acked-by: Jon Maloy <jon.maloy@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/tipc/socket.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1396,8 +1396,10 @@ static int __tipc_sendmsg(struct socket
 	rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
 	if (unlikely(rc != dlen))
 		return rc;
-	if (unlikely(syn && !tipc_msg_skb_clone(&pkts, &sk->sk_write_queue)))
+	if (unlikely(syn && !tipc_msg_skb_clone(&pkts, &sk->sk_write_queue))) {
+		__skb_queue_purge(&pkts);
 		return -ENOMEM;
+	}
 
 	trace_tipc_sk_sendmsg(sk, skb_peek(&pkts), TIPC_DUMP_SK_SNDQ, " ");
 	rc = tipc_node_xmit(net, &pkts, dnode, tsk->portid);