wifi: mac80211: fix multi-BSSID element parsing

When parsing a frame containing a multi-BSSID element, we
need to know both the transmitted and non-transmitted BSSID
so we can parse it correctly.

Unfortunately, in quite a number of cases, we got this wrong
and were passing the wrong BSSID or useless information:
 * the mgmt->bssid from a frame is only the transmitted
   BSSID if the frame is a beacon
 * passing just one of the parameters as non-NULL isn't
   useful and ignored

In those case where we need to parse for a specific BSS we
always have a BSS structure pointer, representing the BSS
we need, whether transmitted or not. Thus, pass that pointer
to the parsing function instead of the two BSSIDs.

Also fix two bugs:
 * we need to re-parse all the elements for the other BSS
   when iterating the non-transmitted BSSes in scan
 * we need to parse for the correct BSS when setting up
   the channel data in client code

Fixes: 78ac51f8 ("mac80211: support multi-bssid")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/agg-rx.c

@@ -502,7 +502,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 				 u.action.u.addba_req.variable);
 	if (ies_len) {
 		elems = ieee802_11_parse_elems(mgmt->u.action.u.addba_req.variable,
-					       ies_len, true, mgmt->bssid, NULL);
+					       ies_len, true, NULL);
 		if (!elems || elems->parse_error)
 			goto free;
 	}

net/mac80211/ibss.c

@@ -1601,8 +1601,7 @@ void ieee80211_rx_mgmt_probe_beacon(struct ieee80211_sub_if_data *sdata,
 		return;
 
 	elems = ieee802_11_parse_elems(mgmt->u.probe_resp.variable,
-				       len - baselen, false,
-				       mgmt->bssid, NULL);
+				       len - baselen, false, NULL);
 
 	if (elems) {
 		ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, elems);
@@ -1655,7 +1654,7 @@ void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 
 			elems = ieee802_11_parse_elems(
 				mgmt->u.action.u.chan_switch.variable,
-				ies_len, true, mgmt->bssid, NULL);
+				ies_len, true, NULL);
 
 			if (elems && !elems->parse_error)
 				ieee80211_rx_mgmt_spectrum_mgmt(sdata, mgmt,

net/mac80211/ieee80211_i.h

@@ -2147,10 +2147,9 @@ static inline void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata,
  * @filter: bitmap of element IDs to filter out while calculating
  *	the element CRC
  * @crc: CRC starting value
- * @transmitter_bssid: transmitter BSSID to parse the multi-BSSID
- *	element
- * @bss_bssid: BSSID of the BSS we want to obtain elements for
- *	when parsing the multi-BSSID element
+ * @bss: the BSS to parse this as, for multi-BSSID cases this can
+ *	represent a non-transmitting BSS in which case the data
+ *	for that non-transmitting BSS is returned
  */
 struct ieee80211_elems_parse_params {
 	const u8 *start;
@@ -2158,8 +2157,7 @@ struct ieee80211_elems_parse_params {
 	bool action;
 	u64 filter;
 	u32 crc;
-	const u8 *transmitter_bssid;
-	const u8 *bss_bssid;
+	struct cfg80211_bss *bss;
 };
 
 struct ieee802_11_elems *
@@ -2168,8 +2166,7 @@ ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params);
 static inline struct ieee802_11_elems *
 ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action,
 			   u64 filter, u32 crc,
-			   const u8 *transmitter_bssid,
-			   const u8 *bss_bssid)
+			   struct cfg80211_bss *bss)
 {
 	struct ieee80211_elems_parse_params params = {
 		.start = start,
@@ -2177,8 +2174,7 @@ ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action,
 		.action = action,
 		.filter = filter,
 		.crc = crc,
-		.transmitter_bssid = transmitter_bssid,
-		.bss_bssid = bss_bssid,
+		.bss = bss,
 	};
 
 	return ieee802_11_parse_elems_full(&params);
@@ -2186,11 +2182,9 @@ ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action,
 
 static inline struct ieee802_11_elems *
 ieee802_11_parse_elems(const u8 *start, size_t len, bool action,
-		       const u8 *transmitter_bssid,
-		       const u8 *bss_bssid)
+		       struct cfg80211_bss *bss)
 {
-	return ieee802_11_parse_elems_crc(start, len, action, 0, 0,
-					  transmitter_bssid, bss_bssid);
+	return ieee802_11_parse_elems_crc(start, len, action, 0, 0, bss);
 }
 
 

net/mac80211/mesh.c

@@ -1256,8 +1256,7 @@ ieee80211_mesh_rx_probe_req(struct ieee80211_sub_if_data *sdata,
 	if (baselen > len)
 		return;
 
-	elems = ieee802_11_parse_elems(pos, len - baselen, false, mgmt->bssid,
-				       NULL);
+	elems = ieee802_11_parse_elems(pos, len - baselen, false, NULL);
 	if (!elems)
 		return;
 
@@ -1326,7 +1325,7 @@ static void ieee80211_mesh_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
 
 	elems = ieee802_11_parse_elems(mgmt->u.probe_resp.variable,
 				       len - baselen,
-				       false, mgmt->bssid, NULL);
+				       false, NULL);
 	if (!elems)
 		return;
 
@@ -1468,8 +1467,7 @@ static void mesh_rx_csa_frame(struct ieee80211_sub_if_data *sdata,
 	pos = mgmt->u.action.u.chan_switch.variable;
 	baselen = offsetof(struct ieee80211_mgmt,
 			   u.action.u.chan_switch.variable);
-	elems = ieee802_11_parse_elems(pos, len - baselen, true,
-				       mgmt->bssid, NULL);
+	elems = ieee802_11_parse_elems(pos, len - baselen, true, NULL);
 	if (!elems)
 		return;
 

net/mac80211/mesh_hwmp.c

@@ -932,7 +932,7 @@ void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 
 	baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 	elems = ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
-				       len - baselen, false, mgmt->bssid, NULL);
+				       len - baselen, false, NULL);
 	if (!elems)
 		return;
 

net/mac80211/mesh_plink.c

@@ -1229,8 +1229,7 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
 		if (baselen > len)
 			return;
 	}
-	elems = ieee802_11_parse_elems(baseaddr, len - baselen, true,
-				       mgmt->bssid, NULL);
+	elems = ieee802_11_parse_elems(baseaddr, len - baselen, true, NULL);
 	mesh_process_plink_frame(sdata, mgmt, elems, rx_status);
 	kfree(elems);
 }

net/mac80211/mlme.c

@@ -3536,8 +3536,7 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata,
 		}
 
 		bss_elems = ieee802_11_parse_elems(bss_ies->data, bss_ies->len,
-						   false, mgmt->bssid,
-						   assoc_data->bss->bssid);
+						   false, assoc_data->bss);
 		if (!bss_elems) {
 			ret = false;
 			goto out;
@@ -3927,7 +3926,7 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
 		return;
 
 	elems = ieee802_11_parse_elems(pos, len - (pos - (u8 *)mgmt), false,
-				       mgmt->bssid, assoc_data->bss->bssid);
+				       assoc_data->bss);
 	if (!elems)
 		goto notify_driver;
 
@@ -4252,8 +4251,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 	if (ifmgd->assoc_data && ifmgd->assoc_data->need_beacon &&
 	    ieee80211_rx_our_beacon(bssid, ifmgd->assoc_data->bss)) {
 		elems = ieee802_11_parse_elems(variable, len - baselen, false,
-					       bssid,
-					       ifmgd->assoc_data->bss->bssid);
+					       ifmgd->assoc_data->bss);
 		if (!elems)
 			return;
 
@@ -4321,7 +4319,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 		ncrc = crc32_be(0, (void *)&mgmt->u.beacon.beacon_int, 4);
 	elems = ieee802_11_parse_elems_crc(variable, len - baselen,
 					   false, care_about_ies, ncrc,
-					   mgmt->bssid, bssid);
+					   link->u.mgd.bss);
 	if (!elems)
 		return;
 	ncrc = elems->crc;
@@ -4566,7 +4564,7 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 			/* CSA IE cannot be overridden, no need for BSSID */
 			elems = ieee802_11_parse_elems(
 					mgmt->u.action.u.chan_switch.variable,
-					ies_len, true, mgmt->bssid, NULL);
+					ies_len, true, NULL);
 
 			if (elems && !elems->parse_error)
 				ieee80211_sta_process_chanswitch(link,
@@ -4590,7 +4588,7 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 			 */
 			elems = ieee802_11_parse_elems(
 					mgmt->u.action.u.ext_chan_switch.variable,
-					ies_len, true, mgmt->bssid, NULL);
+					ies_len, true, NULL);
 
 			if (elems && !elems->parse_error) {
 				/* for the handling code pretend it was an IE */
@@ -5445,8 +5443,7 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 	rcu_read_lock();
 
 	ies = rcu_dereference(cbss->ies);
-	elems = ieee802_11_parse_elems(ies->data, ies->len, false,
-				       NULL, NULL);
+	elems = ieee802_11_parse_elems(ies->data, ies->len, false, cbss);
 	if (!elems) {
 		rcu_read_unlock();
 		return -ENOMEM;

net/mac80211/scan.c

@@ -209,8 +209,7 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 	if (baselen > len)
 		return NULL;
 
-	elems = ieee802_11_parse_elems(elements, len - baselen, false,
-				       mgmt->bssid, cbss->bssid);
+	elems = ieee802_11_parse_elems(elements, len - baselen, false, cbss);
 	if (!elems)
 		return NULL;
 
@@ -221,16 +220,21 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 
 	bss = (void *)cbss->priv;
 	ieee80211_update_bss_from_elems(local, bss, elems, rx_status, beacon);
+	kfree(elems);
 
 	list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 		non_tx_bss = (void *)non_tx_cbss->priv;
 
+		elems = ieee802_11_parse_elems(elements, len - baselen, false,
+					       non_tx_cbss);
+		if (!elems)
+			continue;
+
 		ieee80211_update_bss_from_elems(local, non_tx_bss, elems,
 						rx_status, beacon);
+		kfree(elems);
 	}
 
-	kfree(elems);
-
 	return bss;
 }
 

net/mac80211/tdls.c

@@ -1720,7 +1720,7 @@ ieee80211_process_tdls_channel_switch_resp(struct ieee80211_sub_if_data *sdata,
 	}
 
 	elems = ieee802_11_parse_elems(tf->u.chan_switch_resp.variable,
-				       skb->len - baselen, false, NULL, NULL);
+				       skb->len - baselen, false, NULL);
 	if (!elems) {
 		ret = -ENOMEM;
 		goto out;
@@ -1838,7 +1838,7 @@ ieee80211_process_tdls_channel_switch_req(struct ieee80211_sub_if_data *sdata,
 	}
 
 	elems = ieee802_11_parse_elems(tf->u.chan_switch_req.variable,
-				       skb->len - baselen, false, NULL, NULL);
+				       skb->len - baselen, false, NULL);
 	if (!elems)
 		return -ENOMEM;
 

net/mac80211/util.c

@@ -1425,15 +1425,14 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 
 static size_t ieee802_11_find_bssid_profile(const u8 *start, size_t len,
 					    struct ieee802_11_elems *elems,
-					    const u8 *transmitter_bssid,
-					    const u8 *bss_bssid,
+					    struct cfg80211_bss *bss,
 					    u8 *nontransmitted_profile)
 {
 	const struct element *elem, *sub;
 	size_t profile_len = 0;
 	bool found = false;
 
-	if (!bss_bssid || !transmitter_bssid)
+	if (!bss || !bss->transmitted_bss)
 		return profile_len;
 
 	for_each_element_id(elem, WLAN_EID_MULTIPLE_BSSID, start, len) {
@@ -1475,11 +1474,11 @@ static size_t ieee802_11_find_bssid_profile(const u8 *start, size_t len,
 				continue;
 			}
 
-			cfg80211_gen_new_bssid(transmitter_bssid,
+			cfg80211_gen_new_bssid(bss->transmitted_bss->bssid,
 					       elem->data[0],
 					       index[2],
 					       new_bssid);
-			if (ether_addr_equal(new_bssid, bss_bssid)) {
+			if (ether_addr_equal(new_bssid, bss->bssid)) {
 				found = true;
 				elems->bssid_index_len = index[1];
 				elems->bssid_index = (void *)&index[2];
@@ -1509,9 +1508,7 @@ ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params)
 	if (nontransmitted_profile) {
 		nontransmitted_profile_len =
 			ieee802_11_find_bssid_profile(params->start, params->len,
-						      elems,
-						      params->transmitter_bssid,
-						      params->bss_bssid,
+						      elems, params->bss,
 						      nontransmitted_profile);
 		non_inherit =
 			cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE,