rndis_host: limit scope of bogus MAC address detection to ZTE devices

Reporting of bogus MAC addresses and ignoring configuration of new
destination address wasn't observed outside of a range of ZTE devices,
among which this seems to be the common bug. Align rndis_host driver
with implementation found in cdc_ether, which also limits this workaround
to ZTE devices.
Suggested-by: Bjørn Mork <bjorn@mork.no>
Cc: Kristian Evensen <kristian.evensen@gmail.com>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Lech Perczak <lech.perczak@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/usb/rndis_host.c

@@ -418,10 +418,7 @@ generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
 		goto halt_fail_and_release;
 	}
 
-	if (bp[0] & 0x02)
-		eth_hw_addr_random(net);
-	else
-		eth_hw_addr_set(net, bp);
+	eth_hw_addr_set(net, bp);
 
 	/* set a nonzero filter to enable data transfers */
 	memset(u.set, 0, sizeof *u.set);
@@ -463,6 +460,16 @@ static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 	return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
 }
 
+static int zte_rndis_bind(struct usbnet *dev, struct usb_interface *intf)
+{
+	int status = rndis_bind(dev, intf);
+
+	if (!status && (dev->net->dev_addr[0] & 0x02))
+		eth_hw_addr_random(dev->net);
+
+	return status;
+}
+
 void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 {
 	struct rndis_halt	*halt;
@@ -615,7 +622,7 @@ static const struct driver_info	zte_rndis_info = {
 	.description =	"ZTE RNDIS device",
 	.flags =	FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 	.data =		RNDIS_DRIVER_DATA_DST_MAC_FIXUP,
-	.bind =		rndis_bind,
+	.bind =		zte_rndis_bind,
 	.unbind =	rndis_unbind,
 	.status =	rndis_status,
 	.rx_fixup =	rndis_rx_fixup,