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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+d6636a36d3c34bd88938@syzkaller.appspotmail.com,
        Cong Wang <xiyou.wangcong@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.19 27/50] netrom: fix a memory leak in nr_rx_frame()
Date:   Fri, 26 Jul 2019 17:25:02 +0200
Message-Id: <20190726152303.423302107@linuxfoundation.org>
In-Reply-To: <20190726152300.760439618@linuxfoundation.org>
References: <20190726152300.760439618@linuxfoundation.org>
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From: Cong Wang <xiyou.wangcong@gmail.com>

[ Upstream commit c8c8218ec5af5d2598381883acbefbf604e56b5e ]

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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
@@ -872,7 +872,7 @@ 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
@@ -971,6 +971,7 @@ 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 */