ixgbevf: fix spoofed packets with random MAC

If ixgbevf is loaded while the corresponding PF interface is down
and the driver assigns a random MAC address, that address can be
overwritten with the value of hw->mac.perm_addr, which would be 0 at
that point.

To avoid this case we init hw->mac.perm_addr to the randomly generated
address and do not set it unless we receive ACK from ixgbe.

Reported-by: John Greene <jogreene@redhat.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

@@ -2664,6 +2664,7 @@ static int ixgbevf_sw_init(struct ixgbevf_adapter *adapter)
 		dev_info(&pdev->dev, "Assigning random MAC address\n");
 		eth_hw_addr_random(netdev);
 		ether_addr_copy(hw->mac.addr, netdev->dev_addr);
+		ether_addr_copy(hw->mac.perm_addr, netdev->dev_addr);
 	}
 
 	/* Enable dynamic interrupt throttling rates */

drivers/net/ethernet/intel/ixgbevf/vf.c

@@ -117,7 +117,9 @@ static s32 ixgbevf_reset_hw_vf(struct ixgbe_hw *hw)
 	    msgbuf[0] != (IXGBE_VF_RESET | IXGBE_VT_MSGTYPE_NACK))
 		return IXGBE_ERR_INVALID_MAC_ADDR;
 
-	ether_addr_copy(hw->mac.perm_addr, addr);
+	if (msgbuf[0] == (IXGBE_VF_RESET | IXGBE_VT_MSGTYPE_ACK))
+		ether_addr_copy(hw->mac.perm_addr, addr);
+
 	hw->mac.mc_filter_type = msgbuf[IXGBE_VF_MC_TYPE_WORD];
 
 	return 0;