From 9ecf90b305220eade0a5634e6e604cf0e4fed796 Mon Sep 17 00:00:00 2001
From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Wed, 14 Mar 2018 21:10:23 +0100
Subject: [PATCH] netlink: avoid a double skb free in genlmsg_mcast()

commit 02a2385f37a7c6594c9d89b64c4a1451276f08eb upstream.

nlmsg_multicast() consumes always the skb, thus the original skb must be
freed only when this function is called with a clone.

Fixes: cb9f7a9a5c96 ("netlink: ensure to loop over all netns in genlmsg_multicast_allns()")
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 net/netlink/genetlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 3b1b2a29e3a3..c41301ab943f 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -942,7 +942,7 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
 	if (!err)
 		delivered = true;
 	else if (err != -ESRCH)
-		goto error;
+		return err;
 	return delivered ? 0 : -ESRCH;
  error:
 	kfree_skb(skb);
-- 
2.39.2