wifi: mac80211: fixes in FILS discovery updates

FILS discovery configuration gets updated only if the maximum interval
is set to a non-zero value, hence there is no way to reset this value
to 0 once set. Replace the check for interval with a new flag which is
set only if the configuration should be updated.

Add similar changes for the unsolicited broadcast probe response handling.
Signed-off-by: Aloka Dixit <quic_alokad@quicinc.com>
Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20230727174100.11721-3-quic_alokad@quicinc.com
[move NULL'ing to else branch to not have intermediate NULL visible]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/cfg.c

@@ -952,25 +952,29 @@ static int ieee80211_set_fils_discovery(struct ieee80211_sub_if_data *sdata,
 	struct fils_discovery_data *new, *old = NULL;
 	struct ieee80211_fils_discovery *fd;
 
-	if (!params->tmpl || !params->tmpl_len)
-		return -EINVAL;
+	if (!params->update)
+		return 0;
 
 	fd = &link_conf->fils_discovery;
 	fd->min_interval = params->min_interval;
 	fd->max_interval = params->max_interval;
 
 	old = sdata_dereference(link->u.ap.fils_discovery, sdata);
-	new = kzalloc(sizeof(*new) + params->tmpl_len, GFP_KERNEL);
-	if (!new)
-		return -ENOMEM;
-	new->len = params->tmpl_len;
-	memcpy(new->data, params->tmpl, params->tmpl_len);
-	rcu_assign_pointer(link->u.ap.fils_discovery, new);
-
 	if (old)
 		kfree_rcu(old, rcu_head);
 
-	return 0;
+	if (params->tmpl && params->tmpl_len) {
+		new = kzalloc(sizeof(*new) + params->tmpl_len, GFP_KERNEL);
+		if (!new)
+			return -ENOMEM;
+		new->len = params->tmpl_len;
+		memcpy(new->data, params->tmpl, params->tmpl_len);
+		rcu_assign_pointer(link->u.ap.fils_discovery, new);
+	} else {
+		RCU_INIT_POINTER(link->u.ap.fils_discovery, NULL);
+	}
+
+	return BSS_CHANGED_FILS_DISCOVERY;
 }
 
 static int
@@ -981,23 +985,27 @@ ieee80211_set_unsol_bcast_probe_resp(struct ieee80211_sub_if_data *sdata,
 {
 	struct unsol_bcast_probe_resp_data *new, *old = NULL;
 
-	if (!params->tmpl || !params->tmpl_len)
-		return -EINVAL;
+	if (!params->update)
+		return 0;
 
-	old = sdata_dereference(link->u.ap.unsol_bcast_probe_resp, sdata);
-	new = kzalloc(sizeof(*new) + params->tmpl_len, GFP_KERNEL);
-	if (!new)
-		return -ENOMEM;
-	new->len = params->tmpl_len;
-	memcpy(new->data, params->tmpl, params->tmpl_len);
-	rcu_assign_pointer(link->u.ap.unsol_bcast_probe_resp, new);
+	link_conf->unsol_bcast_probe_resp_interval = params->interval;
 
+	old = sdata_dereference(link->u.ap.unsol_bcast_probe_resp, sdata);
 	if (old)
 		kfree_rcu(old, rcu_head);
 
-	link_conf->unsol_bcast_probe_resp_interval = params->interval;
+	if (params->tmpl && params->tmpl_len) {
+		new = kzalloc(sizeof(*new) + params->tmpl_len, GFP_KERNEL);
+		if (!new)
+			return -ENOMEM;
+		new->len = params->tmpl_len;
+		memcpy(new->data, params->tmpl, params->tmpl_len);
+		rcu_assign_pointer(link->u.ap.unsol_bcast_probe_resp, new);
+	} else {
+		RCU_INIT_POINTER(link->u.ap.unsol_bcast_probe_resp, NULL);
+	}
 
-	return 0;
+	return BSS_CHANGED_UNSOL_BCAST_PROBE_RESP;
 }
 
 static int ieee80211_set_ftm_responder_params(
@@ -1428,23 +1436,18 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
 	if (err < 0)
 		goto error;
 
-	if (params->fils_discovery.max_interval) {
-		err = ieee80211_set_fils_discovery(sdata,
-						   &params->fils_discovery,
-						   link, link_conf);
-		if (err < 0)
-			goto error;
-		changed |= BSS_CHANGED_FILS_DISCOVERY;
-	}
+	err = ieee80211_set_fils_discovery(sdata, &params->fils_discovery,
+					   link, link_conf);
+	if (err < 0)
+		goto error;
+	changed |= err;
 
-	if (params->unsol_bcast_probe_resp.interval) {
-		err = ieee80211_set_unsol_bcast_probe_resp(sdata,
-							   &params->unsol_bcast_probe_resp,
-							   link, link_conf);
-		if (err < 0)
-			goto error;
-		changed |= BSS_CHANGED_UNSOL_BCAST_PROBE_RESP;
-	}
+	err = ieee80211_set_unsol_bcast_probe_resp(sdata,
+						   &params->unsol_bcast_probe_resp,
+						   link, link_conf);
+	if (err < 0)
+		goto error;
+	changed |= err;
 
 	err = drv_start_ap(sdata->local, sdata, link_conf);
 	if (err) {