From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Thu, 27 Jun 2019 14:30:58 -0700
Subject: netrom: fix a memory leak in nr_rx_frame()
Git-commit: c8c8218ec5af5d2598381883acbefbf604e56b5e
Patch-mainline: 5.3-rc1
References: networking-stable-19_07_25

When the skb is associated with a new sock, just assigning
it to skb->sk is not sufficient, we have to set its destructor
to free the sock properly too.

Reported-by: syzbot+d6636a36d3c34bd88938@syzkaller.appspotmail.com
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 net/netrom/af_netrom.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -871,7 +871,7 @@ int nr_rx_frame(struct sk_buff *skb, str
 	unsigned short frametype, flags, window, timeout;
 	int ret;
 
-	skb->sk = NULL;		/* Initially we don't know who it's for */
+	skb_orphan(skb);
 
 	/*
 	 *	skb->data points to the netrom frame start
@@ -970,6 +970,7 @@ int nr_rx_frame(struct sk_buff *skb, str
 	window = skb->data[20];
 
 	skb->sk             = make;
+	skb->destructor     = sock_efree;
 	make->sk_state	    = TCP_ESTABLISHED;
 
 	/* Fill in his circuit details */