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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - Detect if realloc may return different pointer" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D23695&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=O_yJfGTL-gKADO88pY2R7vfIOSg_qPuLzDOqXo6Cf-Q&s=LTZclJEKj67z3snvSoFKCOqWKCVGyqHkHfBJF8j6Bb4&e=">23695</a>
</td>
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<th>Summary</th>
<td>Detect if realloc may return different pointer
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>3.5
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Static Analyzer
</td>
</tr>
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<th>Assignee</th>
<td>kremenek@apple.com
</td>
</tr>
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<th>Reporter</th>
<td>socketpair@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Suppose code from ndejs :) :
XXXX() {
...
char* base = static_cast<char*>(realloc(buf->base, nread));
xxx = Buffer::Use(env, base, nread);
}
It is obivous that buf->base MAY become garbage. So authors forgot to write
something like:
if (base == NULL)
abort();
buf->base = base;
i.e. Clang should think that after successfull "realloc()", first argument may
point to undefined memory. Also, next code should be valid:
--------------------
retval = realloc(arg)
if (retval == NULL)
return ERR;
if (retval != arg)
arg = retval;
-------------------
But that code may generate memory leak (if arg was not NULL, and realloc
returns NULL)
retval = realloc(arg)
if (retval != arg)
arg = retval;
------------------</pre>
</div>
</p>
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