net: validate HWTSTAMP ioctl parameters

This patch adds a sanity check on the values provided by user space for
the hardware time stamping configuration. If the values lie outside of
the absolute limits, then the ioctl request will be denied.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/net_tstamp.h

@@ -45,7 +45,7 @@ struct hwtstamp_config {
 };
 
 /* possible values for hwtstamp_config->tx_type */
-enum {
+enum hwtstamp_tx_types {
 	/*
 	 * No outgoing packet will need hardware time stamping;
 	 * should a packet arrive which asks for it, no hardware
@@ -72,7 +72,7 @@ enum {
 };
 
 /* possible values for hwtstamp_config->rx_filter */
-enum {
+enum hwtstamp_rx_filters {
 	/* time stamp no incoming packet at all */
 	HWTSTAMP_FILTER_NONE,