cfg80211: mark negative frequencies as invalid

Regulatory rules with negative frequencies are now
marked as invalid in is_valid_reg_rule().
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/wireless/reg.c

@@ -330,7 +330,7 @@ static bool is_valid_reg_rule(const struct ieee80211_reg_rule *rule)
 	const struct ieee80211_freq_range *freq_range = &rule->freq_range;
 	u32 freq_diff;
 
-	if (freq_range->start_freq_khz == 0 || freq_range->end_freq_khz == 0)
+	if (freq_range->start_freq_khz <= 0 || freq_range->end_freq_khz <= 0)
 		return false;
 
 	if (freq_range->start_freq_khz > freq_range->end_freq_khz)