netlink: avoid a double skb free in genlmsg_mcast()

[ Upstream commit 02a2385f37a7c6594c9d89b64c4a1451276f08eb ]

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 6f02499ef00725abb6d249a61fd005dbdd413ac0..b9ce82c9440f1cde865a456ca926a6f5782c29a7 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1106,7 +1106,7 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
        if (!err)
                delivered = true;
        else if (err != -ESRCH)
-               goto error;
+               return err;
        return delivered ? 0 : -ESRCH;
  error:
        kfree_skb(skb);