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

From: Date: Fri, 12 Apr 2013 18:51:07 +0000
Subject: Bug #45735 [Com]: preg_match fails with Segmentation Fault on capturing subpattern
References: 1  Groups: php.bugs 
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Edit report at https://bugs.php.net/bug.php?id=45735&edit=1

 ID:                 45735
 Comment by:         johnston dot joshua at gmail dot com
 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:

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.


Previous Comments:
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[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.

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[2013-04-11 16:35:34] michael at writhem dot com

why is this status not a bug?

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[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.

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[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...

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[2008-08-07 13:44:55] johnston dot joshua at gmail dot com

Just for my own personal knowledge, is it the capturing pattern the part that causes the recursion?

If I remove the () part of the pattern I can keep adding 0's to the below code I can trigger a
php memory error but no seg fault.

jjohnston:~$ php -r 'preg_match("/http:\/\/.+\.ru/i", str_repeat("http://google.ru", 2000000));

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