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<base href="https://bugs.freedesktop.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - No validation of returned value leads to null dereference at Annot.cc:5404"
href="https://bugs.freedesktop.org/show_bug.cgi?id=101429">101429</a>
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<th>Summary</th>
<td>No validation of returned value leads to null dereference at Annot.cc:5404
</td>
</tr>
<tr>
<th>Product</th>
<td>poppler
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
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<th>Hardware</th>
<td>All
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>general
</td>
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<th>Assignee</th>
<td>poppler-bugs@lists.freedesktop.org
</td>
</tr>
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<th>Reporter</th>
<td>foca@salesforce.com
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=131960" name="attach_131960" title="Proof of concept">attachment 131960</a> <a href="attachment.cgi?id=131960&action=edit" title="Proof of concept">[details]</a></span>
Proof of concept
No validation of returned value leads to null dereference. The vulnerability is
at 'Annot.cc:5404' in the function 'AnnotScreen::initialize'
Annot.cc
5403 action = LinkAction::parseAction(&obj1,
doc->getCatalog()->getBaseURI());
5404 if (action->getKind() == actionRendition && page == 0) {
5405 error (errSyntaxError, -1, "Invalid Rendition action: associated
screen annotation without P");
5406 delete action;
5407 action = NULL;
5408 ok = gFalse;
5409 }
In 5403 action gets a NULL value when it should be a LinkJavaScript object,
however the getKind method is called in 5404 without checking if action is
valid (!= NULL).
Prior to where the crash occurs, action is assigned a value:
5403 action = LinkAction::parseAction(&obj1,
doc->getCatalog()->getBaseURI());
The line above calls the parseAction function with the object1 and a base URI
that contains '0x7fffffffded0: "\020\337\377\377\377\177"' as baseURI which is
not valid and so null is returned for action as shown below:
Link.cc
133 // action is missing or wrong type
134 } else {
135 error(errSyntaxWarning, -1, "parseAction: Unknown annotation action
object: URI = '{0:s}'",
136 baseURI ? baseURI->getCString() : "NULL");
137 action = NULL;
138 }
This could be fixed just checking for action != NULL after Annot.cc:5403
PoC is attached.
This vulnerability has been found by Offensive Research at Salesforce.com:
Alberto Garcia (@algillera), Francisco Oca (@francisco_oca) & Suleman Ali
(@Salbei_)</pre>
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