VLAN: Use stack instead of heap allocation for new interface name

The VLAN ifname is limited to the maximum length of IFNAMSIZ, so there
is no need to use heap allocation for it.

Signed-off-by: Michael Braun <michael-dev@fami-braun.de>

src/ap/vlan_init.c

@@ -1119,25 +1119,23 @@ struct hostapd_vlan * vlan_add_dynamic(struct hostapd_data *hapd,
 				       int vlan_id,
 				       struct vlan_description *vlan_desc)
 {
-	struct hostapd_vlan *n = NULL;
-	char *ifname, *pos;
+	struct hostapd_vlan *n;
+	char ifname[IFNAMSIZ + 1], *pos;
 
 	if (vlan == NULL || vlan->vlan_id != VLAN_ID_WILDCARD)
 		return NULL;
 
 	wpa_printf(MSG_DEBUG, "VLAN: %s(vlan_id=%d ifname=%s)",
 		   __func__, vlan_id, vlan->ifname);
-	ifname = os_strdup(vlan->ifname);
-	if (ifname == NULL)
-		return NULL;
+	os_strlcpy(ifname, vlan->ifname, sizeof(ifname));
 	pos = os_strchr(ifname, '#');
 	if (pos == NULL)
-		goto free_ifname;
+		return NULL;
 	*pos++ = '\0';
 
 	n = os_zalloc(sizeof(*n));
 	if (n == NULL)
-		goto free_ifname;
+		return NULL;
 
 	n->vlan_id = vlan_id;
 	if (vlan_desc)
@@ -1155,11 +1153,8 @@ struct hostapd_vlan * vlan_add_dynamic(struct hostapd_data *hapd,
 		hapd->conf->vlan = n->next;
 		os_free(n);
 		n = NULL;
-		goto free_ifname;
 	}
 
-free_ifname:
-	os_free(ifname);
 	return n;
 }