Get ready for some WTF-ery Crypt takes an optional salt. If that value is an MD5 hash it is prefixed with the chars $1$ to tell the underlying crypt(3) function to use Modular Crypt Format[1].

MCF is an ad-hoc cruft because the orginal crypt() is weak.

Anyway guess who did it :

"let's use strlcpy/strlcat instead for these static string copies" - Rasmus I guess that's Lerdorf himself

Whoever it was also didn't check the return values for error. Strlcat returns the length of the new string which might not be the same as strlen(dst) + strlen(src).

"I'm not a real programmer. I throw together things until it works then I move on." - Rasmus Lerdorf

Here's where he broke it : Sun Aug 7 16:10:34 2011 UTC http://svn.php.net/viewvc/php/php-src/trunk/ext/standard/php...

Here's it being fixed : Fri Aug 19 22:49:18 2011 UTC http://svn.php.net/viewvc/php/php-src/trunk/ext/standard/php...

[1] http://packages.python.org/passlib/modular_crypt_format.html