[PATCH 4.14 26/37] Bluetooth: SCO: Fix sco_send_frame returning skb->len

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

commit 037ce005af6b8a3e40ee07c6e9266c8997e6a4d6 upstream.

The skb in modified by hci_send_sco which pushes SCO headers thus
changing skb->len causing sco_sock_sendmsg to fail.

Fixes: 0771cbb3b97d ("Bluetooth: SCO: Replace use of memcpy_from_msg with bt_skb_sendmsg")
Tested-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/bluetooth/sco.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -282,16 +282,17 @@ static int sco_connect(struct hci_dev *h
 static int sco_send_frame(struct sock *sk, struct sk_buff *skb)
 {
 	struct sco_conn *conn = sco_pi(sk)->conn;
+	int len = skb->len;
 
 	/* Check outgoing MTU */
-	if (skb->len > conn->mtu)
+	if (len > conn->mtu)
 		return -EINVAL;
 
-	BT_DBG("sk %p len %d", sk, skb->len);
+	BT_DBG("sk %p len %d", sk, len);
 
 	hci_send_sco(conn->hcon, skb);
 
-	return skb->len;
+	return len;
 }
 
 static void sco_recv_frame(struct sco_conn *conn, struct sk_buff *skb)
@@ -732,7 +733,8 @@ static int sco_sock_sendmsg(struct socke
 		err = -ENOTCONN;
 
 	release_sock(sk);
-	if (err)
+
+	if (err < 0)
 		kfree_skb(skb);
 	return err;
 }