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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 - Uninitialized memory read in GfxState.cc:4041"
href="https://bugs.freedesktop.org/show_bug.cgi?id=101502">101502</a>
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<th>Summary</th>
<td>Uninitialized memory read in GfxState.cc:4041
</td>
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<th>Product</th>
<td>poppler
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
</td>
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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
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<th>Reporter</th>
<td>foca@salesforce.com
</td>
</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=132067" name="attach_132067" title="Proof of concept">attachment 132067</a> <a href="attachment.cgi?id=132067&action=edit" title="Proof of concept">[details]</a></span>
Proof of concept
There is a uninitialized memory read that leads to a Denial of Service.
The PoC crashes in the following line:
Program received signal SIGSEGV, Segmentation fault.
0x0000000000436480 in Function::getOutputSize (this=0x2f502f2052203020) at
Function.h:77
77 int getOutputSize() { return n; }
Just before call the function, GfxUnivariateShading::getColor at
GfxState.cc:4041
4041 nComps = nFuncs * funcs[0]->getOutputSize();
The variable funcs is an array of nFuncs elements. But in the PoC the number of
elements, nFuncs is 0, but still the code is accessing the first element,
funcs[0], using uninitialized memory data. The program is expecting to get a
pointer with funcs[0] and it crashes when it dereferences an invalid pointer.
The fix would be to check if there is at least one element before accessing the
first one:
4041 if (nFuncs >= 1)
4042 nComps = nFuncs * funcs[0]->getOutputSize();
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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