<html>
<head>
<base href="http://llvm.org/bugs/" />
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Static analysis should've caught CVE-2013-6462"
href="http://llvm.org/bugs/show_bug.cgi?id=18412">18412</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Static analysis should've caught CVE-2013-6462
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Static Analyzer
</td>
</tr>
<tr>
<th>Assignee</th>
<td>kremenek@apple.com
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jeremyhu@apple.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><a href="http://lists.x.org/archives/xorg-announce/2014-January/002389.html">http://lists.x.org/archives/xorg-announce/2014-January/002389.html</a>
CVE-2013-6462 is a vulnerability in libXfont (part of X.org) due to not
properly specifying a buffer size when reading in a string via sscanf.
I have provided a reduced version of the issue, and neither static analysis nor
-Wformat=2 produces any indication of the issue with recent trunk:
~ $ clang-mp-3.5 --version
clang version 3.5 (trunk 198565)
Target: x86_64-apple-darwin13.1.0
Thread model: posix
~ $ scan-build-mp-3.5 clang-mp-3.5 -Wall -Wextra -Wformat=2 -c notcaught.c
scan-build: Using '/opt/local/libexec/llvm-3.5/bin/clang' for static analysis
scan-build: Removing directory
'/var/folders/1b/f1bzh5152y9bvygzl07fn87m0000gn/T/scan-build-2014-01-07-090611-97009-1'
because it contains no reports.
scan-build: No bugs found.
~ $ cat notcaught.c
#include <stdio.h>
#include <string.h>
int readforme(const char * line, char ** ret) {
char charName[100];
if (sscanf(line, "STARTCHAR %s", charName) != 1) {
*ret = NULL;
return -1;
}
*ret = strdup(charName);
return 0;
}
---
Note that %s needs to be %99s in order to be safe.
---
cppcheck caught the issue:
[lib/libXfont/src/bitmap/bdfread.c:341]: (warning)
scanf without field width limits can crash with huge input data.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>