Bug #45735 [Nab]: preg_match fails with Segmentation Fault on capturing subpattern

Edit report at https://bugs.php.net/bug.php?id=45735&edit=1 ID: 45735 Updated by: rasmus@php.net Reported by: johnston dot joshua at gmail dot com Summary: preg_match fails with Segmentation Fault on capturing subpattern Status: Not a bug Type: Bug Package: PCRE related Operating System: * PHP Version: 5.2CVS, 5.3CVS, 6CVS (2008-08-06) Block user comment: N Private report: N New Comment: The problem here is that there is no way to detect run-away regular expressions here without huge performance and memory penalties. Yes, we could build PCRE in a way that it wouldn't segfault and we could crank up the default backtrack limit to something huge, but it would slow every regex call down by a lot. If PCRE provided a way to handle this in a more graceful manner without the performance hit we would of course use it. Previous Comments: ------------------------------------------------------------------------ [2013-04-12 18:51:07] johnston dot joshua at gmail dot com I agree that something needs to be done about this bug on the php side that doesn't involve custom compiling pcre. In my case way back in '08, I found that the solution was misuse of capturing subpatterns. I was using () for grouping even though I did not need to match subpatterns. In reality I should have been using (:?) which solved my issue. ------------------------------------------------------------------------ [2013-04-12 18:40:49] josh dot adell at gmail dot com Just hit this bug today as well. It would be nice if PHP handled this more gracefully by triggering an error or warning instead of segfaulting. ------------------------------------------------------------------------ [2013-04-11 16:35:34] michael at writhem dot com why is this status not a bug? ------------------------------------------------------------------------ [2011-12-23 13:09:46] vojtech dot kurka at gmail dot com We have hit this bug today on 5.3.8, just sending 70KB variable as an input to preg_match_all(). Please fix this, it took us quite a lot of time to find the root cause. This should never cause a segfault. If the preg_match_all() function would throw a standard PHP error/warning, we would find the problem immeadiately. Debugging such problems is just a waste of time, this bugreport is more than 3 years old. ------------------------------------------------------------------------ [2011-12-15 14:42:35] josiecki at silvercube dot pl Why is this bug status set to "Bogus"? Seems to be unsolved since over three years, and I haven't found a single PHP installation that would not be vulnerable to this, including quite new 5.3.8 installation... ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=45735 -- Edit this bug report at https://bugs.php.net/bug.php?id=45735&edit=1