Garbage in wiki pages, preventing MathJax from running plus information leak

[ghost]

Hi,

I have set up a fresh dokuwiki wiki with the latest released version of the MathJax plugin. In short: it does not work. No rendering takes place whatsoever. I had a look at the HTML source and there is something which caught my attention:

[...]

Copy & Paste didn't really work: what I wanted to show you is some kind of binary garbage between . It includes(!) a directory listing of my dokuwiki home directory!! That's a security problem.

I figured out that this is caused by the following php code in ./lib/plugins/mathjax/action/enable.php:

    // Include config files, if any specified
    $configfiles = $this->getConf('configfile');
    $files = explode(';', $configfiles);
    foreach ($files as $f) {
        $f = trim($f);
        $contents = file_get_contents(DOKU_INC . $f);
        if ($contents) {
            $event->data['script'][] = array(
                'type'    => 'text/x-mathjax-config',
                '_data'   => "\n// " . $f . "\n" . $contents,
            );
        }
    }

When I disable the foreach loop, this binary garbage does NOT appear.

Also, I figured out that when i DO define a mathjax config file, it also works fine. My guess is that the case 'no config file defined' needs some kind of special handling. Because in this case the code will, when $configfiles is empty, try to read the _root_directory_of_thewiki. (On FreeBSD for example you can open and read directories just like files). This will cause a binary-mangled directory listing to be included in the Wiki pages and this prevents the Javascript from running.

Would be great if this could be fixed. I'm not fluent in php at all. Thank you very much! m.

[ghost]

Okay.... obviously my < s c r i p t > ..... < / s c r i p t > got stripped away. Sorry for that.

[liffiton]

Thanks for reporting that. I think you're exactly right about the cause, and I'll have a fix later today or tomorrow once I find a second.

Just out of curiousity, though, are you running it on FreeBSD? I haven't run into this issue on Linux.

[ghost]

Great, thanks for the quick response! Yes, I am running it on FreeBSD. I think on Linux you cannot use the read() primitive to read on a file descriptor which is the result of calling open() on a directory. i.e. on Linux you cannot do 'cat $DIRECTORY'. On FreeBSD you can do that! So, my guess is that the quoted php code somehow depends on this Linux-specific behaviour. Thanks, mel

[liffiton]

Yup, sounds right. It was written in a simple way that relied on the OS to work in a certain way. But it's also an easy fix. Thanks.

[liffiton]

Alright, fixed in b5f3210. (I keep forgetting to use the automatic commit-message issue closing...)