cfg80211: reject channels/chandefs with KHz offset >= 1000

This should be covered by the next MHz, make sure that the
numbers are always normalized.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20200424120103.12b91ecf75f9.I4bf499d58404283bbfacb517d614a816763bccf2@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/chan.c

@@ -147,6 +147,9 @@ bool cfg80211_chandef_valid(const struct cfg80211_chan_def *chandef)
 	if (!chandef->chan)
 		return false;
 
+	if (chandef->freq1_offset >= 1000)
+		return false;
+
 	control_freq = chandef->chan->center_freq;
 
 	switch (chandef->width) {

net/wireless/core.c

@@ -834,6 +834,9 @@ int wiphy_register(struct wiphy *wiphy)
 			sband->channels[i].orig_mpwr =
 				sband->channels[i].max_power;
 			sband->channels[i].band = band;
+
+			if (WARN_ON(sband->channels[i].freq_offset >= 1000))
+				return -EINVAL;
 		}
 
 		for (i = 0; i < sband->n_iftype_data; i++) {