mac80211: ethtool: avoid 32 bit multiplication overflow

The multiplication of 100000 * cfg80211_calculate_bitrate() is a 32 bit
operation and can overflow if cfg80211_calculate_bitrate is greater
than 42949. Although I don't believe this is occurring at present, it
would be safer to avoid the potential overflow by making the constant
100000 an ULL to ensure a 64 multiplication occurs.

Detected by CoverityScan, CID#1468643 ("Unintentional integer overflow")

Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Johannes Berg <[email protected]>

net/mac80211/ethtool.c

@@ -121,11 +121,11 @@ static void ieee80211_get_stats(struct net_device *dev,
 
 
 		if (sinfo->filled & BIT(NL80211_STA_INFO_TX_BITRATE))
-			data[i] = 100000 *
+			data[i] = 100000ULL *
 				cfg80211_calculate_bitrate(&sinfo->txrate);
 		i++;
 		if (sinfo->filled & BIT(NL80211_STA_INFO_RX_BITRATE))
-			data[i] = 100000 *
+			data[i] = 100000ULL *
 				cfg80211_calculate_bitrate(&sinfo->rxrate);
 		i++;