wifi: cfg80211: ensure cfg80211_bss_update frees IEs on error

cfg80211_bss_update is expected to consume the IEs that are passed into
it in the temporary internal BSS. This did not happen in some error
cases (which are also WARN_ON paths), so change the code to use a common
label and use that everywhere.

Signed-off-by: Benjamin Berg <[email protected]>
Reviewed-by: Johannes Berg <[email protected]>
Signed-off-by: Miri Korenblit <[email protected]>
Link: https://msgid.link/20231220133549.8e72ea105e17.Ic81e9431e980419360e97502ce8c75c58793f05a@changeid
Signed-off-by: Johannes Berg <[email protected]>

Author: benzea

net/wireless/scan.c

@@ -1818,15 +1818,15 @@ __cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 		      bool signal_valid, unsigned long ts)
 {
 	struct cfg80211_internal_bss *found = NULL;
+	struct cfg80211_bss_ies *ies;
 
 	if (WARN_ON(!tmp->pub.channel))
-		return NULL;
+		goto free_ies;
 
 	tmp->ts = ts;
 
-	if (WARN_ON(!rcu_access_pointer(tmp->pub.ies))) {
-		return NULL;
-	}
+	if (WARN_ON(!rcu_access_pointer(tmp->pub.ies)))
+		goto free_ies;
 
 	found = rb_find_bss(rdev, tmp, BSS_CMP_REGULAR);
 
@@ -1836,7 +1836,6 @@ __cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 	} else {
 		struct cfg80211_internal_bss *new;
 		struct cfg80211_internal_bss *hidden;
-		struct cfg80211_bss_ies *ies;
 
 		/*
 		 * create a copy -- the "res" variable that is passed in
@@ -1845,15 +1844,8 @@ __cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 		 */
 		new = kzalloc(sizeof(*new) + rdev->wiphy.bss_priv_size,
 			      GFP_ATOMIC);
-		if (!new) {
-			ies = (void *)rcu_dereference(tmp->pub.beacon_ies);
-			if (ies)
-				kfree_rcu(ies, rcu_head);
-			ies = (void *)rcu_dereference(tmp->pub.proberesp_ies);
-			if (ies)
-				kfree_rcu(ies, rcu_head);
-			return NULL;
-		}
+		if (!new)
+			goto free_ies;
 		memcpy(new, tmp, sizeof(*new));
 		new->refcount = 1;
 		INIT_LIST_HEAD(&new->hidden_list);
@@ -1913,6 +1905,16 @@ __cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 	bss_ref_get(rdev, found);
 
 	return found;
+
+free_ies:
+	ies = (void *)rcu_dereference(tmp->pub.beacon_ies);
+	if (ies)
+		kfree_rcu(ies, rcu_head);
+	ies = (void *)rcu_dereference(tmp->pub.proberesp_ies);
+	if (ies)
+		kfree_rcu(ies, rcu_head);
+
+	return NULL;
 }
 
 struct cfg80211_internal_bss *