[PATCH 4.9 14/94] net/packet: fix missing net_device reference release

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Douglas Caetano dos Santos <douglascs@xxxxxxxxxxxxx>


[ Upstream commit d19b183cdc1fa3d70d6abe2a4c369e748cd7ebb8 ]

When using a TX ring buffer, if an error occurs processing a control
message (e.g. invalid message), the net_device reference is not
released.

Fixes c14ac9451c348 ("sock: enable timestamping using control messages")
Signed-off-by: Douglas Caetano dos Santos <douglascs@xxxxxxxxxxxxx>
Acked-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/packet/af_packet.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2652,13 +2652,6 @@ static int tpacket_snd(struct packet_soc
 		dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
 	}
 
-	sockc.tsflags = po->sk.sk_tsflags;
-	if (msg->msg_controllen) {
-		err = sock_cmsg_send(&po->sk, msg, &sockc);
-		if (unlikely(err))
-			goto out;
-	}
-
 	err = -ENXIO;
 	if (unlikely(dev == NULL))
 		goto out;
@@ -2666,6 +2659,13 @@ static int tpacket_snd(struct packet_soc
 	if (unlikely(!(dev->flags & IFF_UP)))
 		goto out_put;
 
+	sockc.tsflags = po->sk.sk_tsflags;
+	if (msg->msg_controllen) {
+		err = sock_cmsg_send(&po->sk, msg, &sockc);
+		if (unlikely(err))
+			goto out_put;
+	}
+
 	if (po->sk.sk_socket->type == SOCK_RAW)
 		reserve = dev->hard_header_len;
 	size_max = po->tx_ring.frame_size