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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Adding this to glanceclient is probably acceptable since the worst abuse of it would be to disrupt a user’s local machine until they terminated the process,
 but adding this to Horizon is a no-go.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Django removed the “verify_exists” option from URLField in Django 1.5 for very good reasons. Here’s the release notes summary:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">“django.db.models.fields.URLField.verify_exists will be removed. The feature was deprecated in 1.3.1 due to intractable security and performance issues and
 will follow a slightly accelerated deprecation timeframe.”<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Note that “intractable security issues” bit. Doing this type of validation server-side opens you up to some nasty DoS attacks and simply shouldn’t be done.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">If you have further questions, I recommend talking to Paul McMillan, who was the original reporter of the security issues with “verify_exists” in Django.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">All the best,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">         
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Gabriel<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Victor Joel Morales Ruvalcaba [mailto:chipahuac@hotmail.com]
<br>
<b>Sent:</b> Monday, January 20, 2014 9:44 AM<br>
<b>To:</b> openstack-dev@lists.openstack.org<br>
<b>Subject:</b> [openstack-dev] Can somebody help me to determine if an URL validation in python-glanceclient & horizon projects is safe<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif"">I'm implementing an URL validation that checks if the external location value provided exists and if it's reachable.  To achieve that I'm using the method urlopen of six.moves.urllib.request
 module which it seems similar like to the deprecated django's method of verify_exists.  I'm wondering if I can proceed with the current implementation or if there's a way to implement those validations<br>
<br>
<a href="https://review.openstack.org/#/c/64295/">https://review.openstack.org/#/c/64295/</a><br>
<a href="https://review.openstack.org/#/c/64312/">https://review.openstack.org/#/c/64312/</a><o:p></o:p></span></p>
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