mac80211: fix memory leaks with element parsing

My previous commit 5d24828 ("mac80211: always allocate
struct ieee802_11_elems") had a few bugs and leaked the new
allocated struct in a few error cases, fix that.

Fixes: 5d24828 ("mac80211: always allocate struct ieee802_11_elems")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20211001211108.9839928e42e0.Ib81ca187d3d3af7ed1bfeac2e00d08a4637c8025@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/agg-rx.c

@@ -498,13 +498,14 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 		elems = ieee802_11_parse_elems(mgmt->u.action.u.addba_req.variable,
 					       ies_len, true, mgmt->bssid, NULL);
 		if (!elems || elems->parse_error)
-			return;
+			goto free;
 	}
 
 	__ieee80211_start_rx_ba_session(sta, dialog_token, timeout,
 					start_seq_num, ba_policy, tid,
 					buf_size, true, false,
 					elems ? elems->addba_ext_ie : NULL);
+free:
 	kfree(elems);
 }
 

net/mac80211/ibss.c

@@ -1659,11 +1659,11 @@ void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 				mgmt->u.action.u.chan_switch.variable,
 				ies_len, true, mgmt->bssid, NULL);
 
-			if (!elems || elems->parse_error)
-				break;
-
-			ieee80211_rx_mgmt_spectrum_mgmt(sdata, mgmt, skb->len,
-							rx_status, elems);
+			if (elems && !elems->parse_error)
+				ieee80211_rx_mgmt_spectrum_mgmt(sdata, mgmt,
+								skb->len,
+								rx_status,
+								elems);
 			kfree(elems);
 			break;
 		}

net/mac80211/mlme.c

@@ -3353,8 +3353,10 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata,
 			bss_ies = kmemdup(ies, sizeof(*ies) + ies->len,
 					  GFP_ATOMIC);
 		rcu_read_unlock();
-		if (!bss_ies)
-			return false;
+		if (!bss_ies) {
+			ret = false;
+			goto out;
+		}
 
 		bss_elems = ieee802_11_parse_elems(bss_ies->data, bss_ies->len,
 						   false, mgmt->bssid,
@@ -4331,13 +4333,11 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 					mgmt->u.action.u.chan_switch.variable,
 					ies_len, true, mgmt->bssid, NULL);
 
-			if (!elems || elems->parse_error)
-				break;
-
-			ieee80211_sta_process_chanswitch(sdata,
-						 rx_status->mactime,
-						 rx_status->device_timestamp,
-						 elems, false);
+			if (elems && !elems->parse_error)
+				ieee80211_sta_process_chanswitch(sdata,
+								 rx_status->mactime,
+								 rx_status->device_timestamp,
+								 elems, false);
 			kfree(elems);
 		} else if (mgmt->u.action.category == WLAN_CATEGORY_PUBLIC) {
 			struct ieee802_11_elems *elems;
@@ -4357,17 +4357,17 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 					mgmt->u.action.u.ext_chan_switch.variable,
 					ies_len, true, mgmt->bssid, NULL);
 
-			if (!elems || elems->parse_error)
-				break;
+			if (elems && !elems->parse_error) {
+				/* for the handling code pretend it was an IE */
+				elems->ext_chansw_ie =
+					&mgmt->u.action.u.ext_chan_switch.data;
 
-			/* for the handling code pretend this was also an IE */
-			elems->ext_chansw_ie =
-				&mgmt->u.action.u.ext_chan_switch.data;
+				ieee80211_sta_process_chanswitch(sdata,
+								 rx_status->mactime,
+								 rx_status->device_timestamp,
+								 elems, false);
+			}
 
-			ieee80211_sta_process_chanswitch(sdata,
-						 rx_status->mactime,
-						 rx_status->device_timestamp,
-						 elems, false);
 			kfree(elems);
 		}
 		break;