Bug #60664 [Opn->Nab]: mb_ereg leads to script executing timeout

Edit report at https://bugs.php.net/bug.php?id=60664&edit=1 ID: 60664 Updated by: cmb@php.net Reported by: tyz at open dot by Summary: mb_ereg leads to script executing timeout -Status: Open +Status: Not a bug Type: Bug Package: mbstring related Operating System: Debian PHP Version: 5.3.8 -Assigned To: +Assigned To: cmb Block user comment: N Private report: N New Comment: > The pattern you're using is a typical case of catastrophic > backtracking. Indeed (thanks for the explanation!). Running this regex with PCRE would quickly bail out with PREG_BACKTRACK_LIMIT_ERROR. AIUI, request #72777 would similarly solve the issue for mb_ereg(). Previous Comments: ------------------------------------------------------------------------ [2016-07-30 12:45:35] ju1ius at laposte dot net This is not a bug. You should fix your regexp first. The pattern you're using is a typical case of catastrophic backtracking. http://www.regular-expressions.info/catastrophic.html You can test it here: https://regex101.com/ and see that any regexp engine will have a really hard time matching this pattern. ------------------------------------------------------------------------ [2016-07-30 11:34:00] cmb@php.net Might be related to bug #53099. ------------------------------------------------------------------------ [2012-01-05 12:57:15] tyz at open dot by Description: ------------ I tried this with php 5.3.8 and 5.3.2 with the same results. Test script: --------------- <?php $content = '<div class="private-sales-index"> <div class="box"> <div class="content"> <h1>Welcome to our Exclusive Online Store</h1> <p>If you are a registered member, please <a href="{{store url="customer/account/login"}}">log in here</a>.</p> <p class="description">Magento is the leading hub for exclusive specialty items for all your home, apparel and entertainment needs!</p> </div> </div> </div>'; $content = mbereg_replace("\r\n", ' ', $content); $content = mbereg_replace("\n", ' ', $content); var_dump($content); var_dump(mb_ereg('(.*?\s){100}', $content, $_m)); var_dump($_m); Expected result: ---------------- $content should be truncated to string that contains ~100 words. Actual result: -------------- Script executing hangs. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=60664&edit=1