From d6aa71197ffcb68850bfebfc3fc160abe41df53b Mon Sep 17 00:00:00 2001
From: William Tu <u9012063@gmail.com>
Date: Fri, 9 Mar 2018 07:34:41 -0800
Subject: [PATCH] ip6erspan: improve error handling for erspan version number.

When users fill in incorrect erspan version number through
the struct erspan_metadata uapi, current code skips pushing
the erspan header but continue pushing the gre header, which
is incorrect.  The patch fixes it by returning error.

Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv6/ip6_gre.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 83c2fffd40be..a299f5424e16 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -945,6 +945,8 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
 					       md->u.md2.dir,
 					       get_hwid(&md->u.md2),
 					       truncate, false);
+		} else {
+			goto tx_err;
 		}
 	} else {
 		switch (skb->protocol) {