[wp-hackers] preg_match_all() Crashes Server

[peter baylies]

What PHP version is being used? It could be a bug...
https://bugs.php.net/bug.php?id=28513

Cheers,

 -- Peter

On Wed, Mar 13, 2013 at 11:01 AM, Mike Walsh <mpwalsh8 at gmail.com> wrote:

> A user of my WordPress Google Form plugin has run into an odd problem where
> visiting the Plugin Settings page results in a server crash.  I can't
> replicate it but he provided me access to a test site where I was able to
> determine that a call to preg_match_all() is what is crashing the server.
>
> I am not sure how to resolve this.  What I am doing is using
> wp_remote_get() to scrape the FAQ and Usage content for my plugin from the
> WordPress Plugin Repository (the content from the ReadMe file), extract
> what I want, and put the content on a tab on my Settings Page.  Doing this
> allowed me an easy way to add Help to my plugin within the Settings Page.
>
> I've put a fragment of the code here in PastBin:
> http://pastebin.com/RrYxAdiU
>
> This is the regular expression which fails:
>
>         $pattern_short =
>
> '{<div\s+[^>]*?class="block-content"[^>]*>((?:(?:(?!<div[^>]*>|</div>).)++|<div[^>]*>(?1)</div>)*)</div>}si';
>         $matchcount = preg_match_all($pattern_short, $data, $matches);
>
> After Googling a bit I thought the user might have an incorrect setting for
> pcre.backtrace_limit but his value (100000) is the same as what I have on
> my server.
>
> I am not sure what else to check at this point.
>
> --
> Mike Walsh - mpwalsh8 at gmail.com
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