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      <title>Securing &#34;tmp&#34; without repartition</title>
      <link>https://www.deepreflect.net/2010/01/16/securing-tmp/</link>
      <pubDate>Sat, 16 Jan 2010 22:57:24 +0000</pubDate>
       <guid isPermaLink="false">http://blog.deepreflect.net/?p=786</guid> 
      <description>&lt;ol&gt;
&lt;li&gt;First you should secure /tmp:&lt;/li&gt;
&lt;/ol&gt;
&lt;p&gt;Make a 1GB file for /tmp parition and an ext3 filesystem for tmp:&lt;/p&gt;
&lt;div class=&#34;highlight&#34;&gt;&lt;pre tabindex=&#34;0&#34; style=&#34;color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;&#34;&gt;&lt;code class=&#34;language-fallback&#34; data-lang=&#34;fallback&#34;&gt;&lt;span style=&#34;display:flex;&#34;&gt;&lt;span&gt;# dd if=/dev/zero of=/dev/tmpFS bs=1024 count=1000000
&lt;/span&gt;&lt;/span&gt;&lt;span style=&#34;display:flex;&#34;&gt;&lt;span&gt;# /sbin/mkfs.ext3 /dev/tmpFS
&lt;/span&gt;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/div&gt;&lt;p&gt;Create a backup copy of your current /tmp drive:&lt;/p&gt;
&lt;p&gt;&lt;code&gt;# cp -Rpf /tmp /tmpbackup&lt;/code&gt;&lt;/p&gt;
&lt;p&gt;Mount our new tmp parition and change permissions:&lt;/p&gt;
&lt;div class=&#34;highlight&#34;&gt;&lt;pre tabindex=&#34;0&#34; style=&#34;color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;&#34;&gt;&lt;code class=&#34;language-fallback&#34; data-lang=&#34;fallback&#34;&gt;&lt;span style=&#34;display:flex;&#34;&gt;&lt;span&gt;# mount -o loop,noexec,nosuid,rw /dev/tmpFS /tmp
&lt;/span&gt;&lt;/span&gt;&lt;span style=&#34;display:flex;&#34;&gt;&lt;span&gt;# chmod 1777 /tmp
&lt;/span&gt;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/div&gt;&lt;p&gt;Copy the old data:
&lt;code&gt;cp -Rpf /tmpbackup/\* /tmp/&lt;/code&gt;&lt;/p&gt;
&lt;p&gt;If you run the mount command and you should get something like this:
&lt;code&gt;/dev/tmpMnt on /tmp type ext3 (rw,noexec,nosuid,loop=/dev/loop0)&lt;/code&gt;&lt;/p&gt;</description>
      <content:encoded><![CDATA[<ol>
<li>First you should secure /tmp:</li>
</ol>
<p>Make a 1GB file for /tmp parition and an ext3 filesystem for tmp:</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-fallback" data-lang="fallback"><span style="display:flex;"><span># dd if=/dev/zero of=/dev/tmpFS bs=1024 count=1000000
</span></span><span style="display:flex;"><span># /sbin/mkfs.ext3 /dev/tmpFS
</span></span></code></pre></div><p>Create a backup copy of your current /tmp drive:</p>
<p><code># cp -Rpf /tmp /tmpbackup</code></p>
<p>Mount our new tmp parition and change permissions:</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-fallback" data-lang="fallback"><span style="display:flex;"><span># mount -o loop,noexec,nosuid,rw /dev/tmpFS /tmp
</span></span><span style="display:flex;"><span># chmod 1777 /tmp
</span></span></code></pre></div><p>Copy the old data:
<code>cp -Rpf /tmpbackup/\* /tmp/</code></p>
<p>If you run the mount command and you should get something like this:
<code>/dev/tmpMnt on /tmp type ext3 (rw,noexec,nosuid,loop=/dev/loop0)</code></p>
<p>Edit /etc/fstab and add this:</p>
<p><code>/dev/tmpMnt /tmp ext3 loop,nosuid,noexec,rw 0 0</code></p>
<p>Test your fstab entry:</p>
<p><code># mount -o remount /tmp</code></p>
<p>You can test it runnig a script on /tmp partition, if you get &ldquo;permission denied&rdquo; it is fine :)</p>
<ol start="2">
<li>Secure /var/tmp:</li>
</ol>
<p>It should be done because some applications use /var/tmp as the temporary folder, and anything that&rsquo;s accessible by all, needs to be secured.</p>
<p>Rename it and create a symbolic link to /tmp:</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-gdscript3" data-lang="gdscript3"><span style="display:flex;"><span><span style="color:#75715e"># mv /var/tmp /var/tmp1</span>
</span></span><span style="display:flex;"><span><span style="color:#75715e"># ln -s /tmp /var/tmp </span>
</span></span></code></pre></div><p>Copy the old data back:</p>
<p><code># cp /var/tmpold/* /tmp/</code></p>
<p>Note: you should restart and services that uses /tmp partition</p>
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