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<title>Twisted Documentation: Security</title>
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<link href="../howto/stylesheet.css" rel="stylesheet" type="text/css"/>
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<h1 class="title">Security</h1>
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<div class="toc"><ol><li><a href="#auto0">Bad input</a></li><li><a href="#auto1">Resource Exhaustion and DoS</a></li></ol></div>
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<p>We need to do a full audit of Twisted, module by module.
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This document list the sort of things you want to look for
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when doing this, or when writing your own code.</p>
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<h2>Bad input<a name="auto0"/></h2>
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<p>Any place we receive untrusted data, we need to be careful.
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In some cases we are not careful enough. For example, in HTTP
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there are many places where strings need to be converted to
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ints, so we use <code class="python">int()</code>. The problem
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is that this well accept negative numbers as well, whereas
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the protocol should only be accepting positive numbers.</p>
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<h2>Resource Exhaustion and DoS<a name="auto1"/></h2>
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<p>Make sure we never allow users to create arbitarily large
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strings or files. Some of the protocols still have issues
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like this. Place a limit which allows reasonable use but
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will cut off huge requests, and allow changing of this limit.
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<p>Another operation to look out for are exceptions. They can fill
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up logs and take a lot of CPU time to render in web pages.</p>
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<p><a href="../howto/index.html">Index</a></p>
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<span class="version">Version: 10.0.0</span>
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