Bluetooth: ISO: Fix info leak in iso_sock_getsockopt()

The C standard rules for when struct holes are zeroed out are slightly
weird.  The existing assignments might initialize everything, but GCC
is allowed to (and does sometimes) leave the struct holes uninitialized,
so instead of using yet another variable and copy the QoS settings just
use a pointer to the stored QoS settings.

Fixes: ccf74f23 ("Bluetooth: Add BTPROTO_ISO socket type")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

net/bluetooth/iso.c

@@ -1235,7 +1235,7 @@ static int iso_sock_getsockopt(struct socket *sock, int level, int optname,
 {
 	struct sock *sk = sock->sk;
 	int len, err = 0;
-	struct bt_iso_qos qos;
+	struct bt_iso_qos *qos;
 	u8 base_len;
 	u8 *base;
 
@@ -1261,12 +1261,12 @@ static int iso_sock_getsockopt(struct socket *sock, int level, int optname,
 
 	case BT_ISO_QOS:
 		if (sk->sk_state == BT_CONNECTED || sk->sk_state == BT_CONNECT2)
-			qos = iso_pi(sk)->conn->hcon->iso_qos;
+			qos = &iso_pi(sk)->conn->hcon->iso_qos;
 		else
-			qos = iso_pi(sk)->qos;
+			qos = &iso_pi(sk)->qos;
 
-		len = min_t(unsigned int, len, sizeof(qos));
-		if (copy_to_user(optval, (char *)&qos, len))
+		len = min_t(unsigned int, len, sizeof(*qos));
+		if (copy_to_user(optval, qos, len))
 			err = -EFAULT;
 
 		break;