wifi: cfg80211: Do not create BSS entries for unsupported channels

Currently, in cfg80211_parse_ml_elem_sta_data(), when RNR element
indicates a BSS that operates in a channel that current regulatory
domain doesn't support, a NULL value is returned by
ieee80211_get_channel_khz() and assigned to this BSS entry's channel
field. Later in cfg80211_inform_single_bss_data(), the reported
BSS entry's channel will be wrongly overridden by transmitted BSS's.
This could result in connection failure that when wpa_supplicant
tries to select this reported BSS entry while it actually resides in
an unsupported channel.

Since this channel is not supported, it is reasonable to skip such
entries instead of reporting wrong information.

Signed-off-by: Chenming Huang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Johannes Berg <[email protected]>

Author: Chenming Huang

net/wireless/scan.c

@@ -3050,6 +3050,10 @@ cfg80211_parse_ml_elem_sta_data(struct wiphy *wiphy,
 		freq = ieee80211_channel_to_freq_khz(ap_info->channel, band);
 		data.channel = ieee80211_get_channel_khz(wiphy, freq);
 
+		/* Skip if RNR element specifies an unsupported channel */
+		if (!data.channel)
+			continue;
+
 		/* Skip if BSS entry generated from MBSSID or DIRECT source
 		 * frame data available already.
 		 */