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Bug #45822 Invalid value passed to strtotime() causes endless loop
Submitted: 2008-08-14 16:04 UTC Modified: 2009-05-03 18:23 UTC
Avg. Score:5.0 ± 0.0
Reproduced:5 of 5 (100.0%)
Same Version:3 (60.0%)
Same OS:0 (0.0%)
From: matt at neimeyer dot org Assigned: derick (profile)
Status: Closed Package: Date/time related
PHP Version: 5.2CVS, 5.3CVS, 6CVS (2008-08-14) OS: *
Private report: No CVE-ID: None
 [2008-08-14 16:04 UTC] matt at neimeyer dot org
Using a stock installation of PHP 5.2.6 (or 5.2.5 or 5.2.3) as an ISAPI module on Windows 2003 Standard Edition x32 (fully updated using Windows Update), if you pass a "wacky" value to strtotime the w3wp.exe (IIS Worker Pool) spikes to 99% and crashes the web server.

We accidentally used date("-24 hours") instead of strtotime("-24 hours") and then passed that (via some intermediary function calls) to strtotime.

It does not crash on Win2003 SE x64 (or any other operating system that we run this application on).

I am aware of other w3wp.exe bugs being reported but those do not seem to match this specific cause. Similarly, strtotime bugs don't seem to match.

Reproduce code:
echo strtotime(date("-24 hours"));

Expected result:
Return false or -1

(with the caveat that I know it's "bad code" on my part)

Actual result:
w3wp.exe crashes as soon as the page starts to load.

Watching in task manager on the web server, you can see w3wp.exe spike to 99% then stay there. If you kill the task the web server behaves oddly, generating "Service Unavailable" results to the end browser until the "World Wide Web Publishing Service" is restarted.


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 [2008-08-14 17:41 UTC] amelek32 at gmail dot com
echo strtotime('-24 0720080000Thu');

This is enought to this bug. It doesn't really crash, it rather goes to endless loop.

Tested on Apache + PHP 5.2.6 on Windows XP x64
 [2008-08-14 17:50 UTC]
It hangs in this loop:

#1  0x00000000004a7f5b in do_normalize (time=0x7bf1ed0) at /home/jani/php-5.3CVS/ext/date/lib/tm2unixtime.c:166
166             do {} while (do_range_limit_days(&time->y, &time->m, &time->d));
 [2008-08-20 19:24 UTC] krimpet at toolserver dot org
I can confirm this bug, and it's not limited to Windows platforms. 'php -r "strtotime('+1000000000000 days');"' crashes my Linux laptop, for example.

This bug is particularly dire where user input is fed to directly to strtotime(), as it poses a DoS risk - for example, we use strtotime() in MediaWiki to format times specified by the user. (See <>.)
 [2008-12-22 14:18 UTC] for-bugs at hnw dot jp
As well as other comments, php -r 'strtotime("20080101000000 Sunday");' never ends on PHP 5.2.8 and 5.3.0alpha3.
 [2009-05-03 18:23 UTC]
This bug has been fixed in CVS.

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