diff --git a/module/common/model.php b/module/common/model.php
index a64d3c99ca..9b5e69f3d7 100644
--- a/module/common/model.php
+++ b/module/common/model.php
@@ -2670,7 +2670,7 @@ EOD;
         if($isFreepasswd) return print(js::locate($this->config->webRoot));
 
         $this->session->set('ENTRY_CODE', $this->get->code);
-        $this->session->set('VALID_ENTRY', md5(md5($this->get->code) . $this->server->remote_addr));
+        $this->session->set('VALID_ENTRY', md5(md5($this->get->code) . helper::getRemoteIp()));
         $this->loadModel('entry')->saveLog($entry->id, $this->server->request_uri);
 
         /* Add for task #5384. */
@@ -2837,7 +2837,7 @@ EOD;
         commonModel::$requestErrors = array();
 
         if(!is_array($headers)) $headers = (array)$headers;
-        $headers[] = "API-RemoteIP: " . zget($_SERVER, 'REMOTE_ADDR', '');
+        $headers[] = "API-RemoteIP: " . helper::getRemoteIp();
 
         $curl = curl_init();
         curl_setopt($curl, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_0);
@@ -2924,7 +2924,7 @@ EOD;
         commonModel::$requestErrors = array();
 
         if(!is_array($headers)) $headers = (array)$headers;
-        $headers[] = "API-RemoteIP: " . zget($_SERVER, 'REMOTE_ADDR', '');
+        $headers[] = "API-RemoteIP: " . helper::getRemoteIp();
         if($dataType == 'json')
         {
             $headers[] = 'Content-Type: application/json;charset=utf-8';
diff --git a/module/extension/model.php b/module/extension/model.php
index 30dbc63ec7..88e184e6e1 100644
--- a/module/extension/model.php
+++ b/module/extension/model.php
@@ -599,11 +599,11 @@ class extensionModel extends model
                 $file = $appRoot . $file;
                 if(!file_exists($file)) continue;
 
-                if(md5_file($file) != $savedMD5)
+                if(!is_writable($file) or @md5_file($file) != $savedMD5)
                 {
                     $removeCommands[] = PHP_OS == 'Linux' ? "rm -fr $file #changed" : "del $file :changed";
                 }
-                elseif(!@unlink($file))
+                elseif(!is_writable($file) or !@unlink($file))
                 {
                     $removeCommands[] = PHP_OS == 'Linux' ? "rm -fr $file" : "del $file";
                 }
@@ -617,7 +617,7 @@ class extensionModel extends model
             foreach($dirs as $dir)
             {
                 if(!is_dir($appRoot . $dir)) continue;
-                if(!rmdir($appRoot . $dir)) $removeCommands[] = PHP_OS == 'Linux' ? "rm -fr $appRoot$dir" : "rmdir $appRoot$dir /s /q";
+                if(!is_writable($appRoot . $dir) or !rmdir($appRoot . $dir)) $removeCommands[] = PHP_OS == 'Linux' ? "rm -fr $appRoot$dir" : "rmdir $appRoot$dir /s /q";
             }
         }
 
@@ -636,7 +636,10 @@ class extensionModel extends model
     public function cleanModelCache()
     {
         $modelCacheFiles = glob($this->app->getTmpRoot() . 'model/*');
-        foreach($modelCacheFiles as $cacheFile) @unlink($cacheFile);
+        foreach($modelCacheFiles as $cacheFile)
+        {
+            if(is_writable($cacheFile) and !is_dir($cacheFile)) @unlink($cacheFile);
+        }
     }
 
     /**
diff --git a/module/sso/control.php b/module/sso/control.php
index 9b744832a6..e073bece90 100644
--- a/module/sso/control.php
+++ b/module/sso/control.php
@@ -26,7 +26,7 @@ class sso extends control
         $this->app->loadConfig('sso');
         if(!$this->config->sso->turnon) return print($this->locate($locate));
 
-        $userIP = $this->server->remote_addr;
+        $userIP = helper::getRemoteIp();
         $code   = $this->config->sso->code;
         $key    = $this->config->sso->key;
         if($type != 'return')
@@ -135,7 +135,7 @@ class sso extends control
         if($type != 'return')
         {
             $code   = $this->config->sso->code;
-            $userIP = $this->server->remote_addr;
+            $userIP = helper::getRemoteIp();
             $token  = $this->get->token;
             $key    = $this->config->sso->key;
             $auth   = md5($code . $userIP . $token . $key);
@@ -199,7 +199,7 @@ class sso extends control
         if(!$this->session->ssoData) return;
 
         $ssoData = $this->session->ssoData;
-        $userIP  = $this->server->remote_addr;
+        $userIP  = helper::getRemoteIp();
         $code    = $this->config->sso->code;
         $key     = $this->config->sso->key;
         if($ssoData->auth != md5($code . $userIP . $ssoData->token . $key)) return;
diff --git a/module/user/model.php b/module/user/model.php
index ddca3fbfd3..48391ea0bd 100644
--- a/module/user/model.php
+++ b/module/user/model.php
@@ -888,7 +888,7 @@ class userModel extends model
 
         if($user)
         {
-            $ip   = $this->server->remote_addr;
+            $ip   = helper::getRemoteIp();
             $last = $this->server->request_time;
 
             $user->lastTime       = $user->last;