wifi: mac80211: validate assoc response channel config

Due to the earlier restructuring we now mostly ignore
the channel configuration in the association response,
apart from the HT/VHT checks we had.

Don't do that, but parse it and update, also dropping the
association if the AP changed its mode in the response.

Link: https://msgid.link/20240129194108.b3efa5eae60c.I1b70c9fd56781b22cdfdca55d34d69f7d0733e31@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

@@ -867,7 +867,7 @@ ieee80211_determine_chan_mode(struct ieee80211_sub_if_data *sdata,
 
 static int ieee80211_config_bw(struct ieee80211_link_data *link,
 			       struct ieee802_11_elems *elems,
-			       u64 *changed)
+			       bool update, u64 *changed)
 {
 	struct ieee80211_channel *channel = link->conf->chanreq.oper.chan;
 	struct ieee80211_sub_if_data *sdata = link->sdata;
@@ -942,6 +942,11 @@ static int ieee80211_config_bw(struct ieee80211_link_data *link,
 		return -EINVAL;
 	}
 
+	if (!update) {
+		link->conf->chanreq = chanreq;
+		return 0;
+	}
+
 	/*
 	 * We're tracking the current AP here, so don't do any further checks
 	 * here. This keeps us from playing ping-pong with regulatory, without
@@ -4505,6 +4510,8 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 	/*
 	 * We previously checked these in the beacon/probe response, so
 	 * they should be present here. This is just a safety net.
+	 * Note that the ieee80211_config_bw() below would also check
+	 * for this (and more), but this has better error reporting.
 	 */
 	if (!is_6ghz && link->u.mgd.conn.mode >= IEEE80211_CONN_MODE_HT &&
 	    (!elems->wmm_param || !elems->ht_cap_elem || !elems->ht_operation)) {
@@ -4522,6 +4529,14 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 		goto out;
 	}
 
+	/* check/update if AP changed anything in assoc response vs. scan */
+	if (ieee80211_config_bw(link, elems,
+				link_id == assoc_data->assoc_link_id,
+				changed)) {
+		ret = false;
+		goto out;
+	}
+
 	if (WARN_ON(!link->conf->chanreq.oper.chan)) {
 		ret = false;
 		goto out;
@@ -6595,7 +6610,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 
 	changed |= ieee80211_recalc_twt_req(sdata, sband, link, link_sta, elems);
 
-	if (ieee80211_config_bw(link, elems, &changed)) {
+	if (ieee80211_config_bw(link, elems, true, &changed)) {
 		ieee80211_set_disassoc(sdata, IEEE80211_STYPE_DEAUTH,
 				       WLAN_REASON_DEAUTH_LEAVING,
 				       true, deauth_buf);