135 lines
6.1 KiB
HTML
135 lines
6.1 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<title>Security Class : CodeIgniter User Guide</title>
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<style type='text/css' media='all'>@import url('../userguide.css');</style>
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<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
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<script type="text/javascript" src="../nav/nav.js"></script>
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<script type="text/javascript" src="../nav/prototype.lite.js"></script>
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<script type="text/javascript" src="../nav/moo.fx.js"></script>
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<script type="text/javascript" src="../nav/user_guide_menu.js"></script>
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<meta http-equiv='expires' content='-1' />
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<meta http-equiv= 'pragma' content='no-cache' />
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<meta name='robots' content='all' />
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<meta name='author' content='ExpressionEngine Dev Team' />
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<meta name='description' content='CodeIgniter User Guide' />
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</head>
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<body>
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<!-- START NAVIGATION -->
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<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
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<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div>
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<div id="masthead">
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<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
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<tr>
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<td><h1>CodeIgniter User Guide Version 2.1.3</h1></td>
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<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
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</tr>
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</table>
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</div>
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<!-- END NAVIGATION -->
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<!-- START BREADCRUMB -->
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<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
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<tr>
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<td id="breadcrumb">
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<a href="http://codeigniter.com/">CodeIgniter Home</a> ›
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<a href="../index.html">User Guide Home</a> ›
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Security Class
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</td>
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<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td>
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</tr>
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</table>
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<!-- END BREADCRUMB -->
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<br clear="all" />
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<!-- START CONTENT -->
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<div id="content">
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<h1>Security Class</h1>
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<p>The Security Class contains methods that help you create a secure application, processing input data for security.</p>
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<h2>XSS Filtering</h2>
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<p>CodeIgniter comes with a Cross Site Scripting Hack prevention filter which can either run automatically to filter
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all POST and COOKIE data that is encountered, or you can run it on a per item basis. By default it does <strong>not</strong>
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run globally since it requires a bit of processing overhead, and since you may not need it in all cases.</p>
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<p>The XSS filter looks for commonly used techniques to trigger Javascript or other types of code that attempt to hijack cookies
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or do other malicious things. If anything disallowed is encountered it is rendered safe by converting the data to character entities.</p>
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<p>
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Note: This function should only be used to deal with data upon submission. It's not something that should be used for general runtime processing since it requires a fair amount of processing overhead.</p>
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<p>To filter data through the XSS filter use this function:</p>
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<h2>$this->security->xss_clean()</h2>
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<p>Here is an usage example:</p>
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<code>$data = $this->security->xss_clean($data);</code>
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<p>If you want the filter to run automatically every time it encounters POST or COOKIE data you can enable it by opening your
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<kbd>application/config/config.php</kbd> file and setting this:</p>
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<code>$config['global_xss_filtering'] = TRUE;</code>
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<p>Note: If you use the form validation class, it gives you the option of XSS filtering as well.</p>
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<p>An optional second parameter, <dfn>is_image</dfn>, allows this function to be used to test images for potential XSS attacks, useful for file upload security. When this second parameter is set to <dfn>TRUE</dfn>, instead of returning an altered string, the function returns TRUE if the image is safe, and FALSE if it contained potentially malicious information that a browser may attempt to execute.</p>
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<code>if ($this->security->xss_clean($file, TRUE) === FALSE)<br />
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{<br />
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// file failed the XSS test<br />
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}</code>
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<h2>$this->security->sanitize_filename()</h2>
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<p>When accepting filenames from user input, it is best to sanitize them to prevent directory traversal and other security related issues. To do so, use the <dfn>sanitize_filename()</dfn> method of the Security class. Here is an example:</p>
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<code>$filename = $this->security->sanitize_filename($this->input->post('filename'));</code>
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<p>If it is acceptable for the user input to include relative paths, e.g. <kbd>file/in/some/approved/folder.txt</kbd>, you can set the second optional parameter,
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<samp>$relative_path</samp> to TRUE.</p>
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<code>$filename = $this->security->sanitize_filename($this->input->post('filename'), TRUE);</code>
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<!-- @todo write docs for CSRF methods -->
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<h2>Cross-site request forgery (CSRF)</h2>
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<p>You can enable csrf protection by opening your <kbd>application/config/config.php</kbd> file and setting this:</p>
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<code>$config['csrf_protection'] = TRUE;</code>
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<p>If you use the <a href="../helpers/form_helper.html">form helper</a> the <var>form_open()</var> function will automatically insert a hidden csrf field in your forms.</p>
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</div>
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<!-- END CONTENT -->
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<div id="footer">
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<p>
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Previous Topic: <a href="pagination.html">Pagination Class</a>
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·
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<a href="#top">Top of Page</a> ·
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<a href="../index.html">User Guide Home</a> ·
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Next Topic: <a href="sessions.html">Session Class</a>
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</p>
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<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2012 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
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</div>
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</body>
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</html>
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