From: Willem de Bruijn <willemb@google.com>
Date: Wed, 13 Dec 2017 14:41:06 -0500
Subject: sock: free skb in skb_complete_tx_timestamp on error
Git-commit: 35b99dffc3f710cafceee6c8c6ac6a98eb2cb4bf
Patch-mainline: v4.15-rc4
References: networking-stable-17_12_31

skb_complete_tx_timestamp must ingest the skb it is passed. Call
kfree_skb if the skb cannot be enqueued.

Fixes: b245be1f4db1 ("net-timestamp: no-payload only sysctl")
Fixes: 9ac25fc06375 ("net: fix socket refcounting in skb_complete_tx_timestamp()")
Reported-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 net/core/skbuff.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3875,7 +3875,7 @@ void skb_complete_tx_timestamp(struct sk
 	struct sock *sk = skb->sk;
 
 	if (!skb_may_tx_timestamp(sk, false))
-		return;
+		goto err;
 
 	/* Take a reference to prevent skb_orphan() from freeing the socket,
 	 * but only if the socket refcount is not zero.
@@ -3884,7 +3884,11 @@ void skb_complete_tx_timestamp(struct sk
 		*skb_hwtstamps(skb) = *hwtstamps;
 		__skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false);
 		sock_put(sk);
+		return;
 	}
+
+err:
+	kfree_skb(skb);
 }
 EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);