Created attachment 332757 [details]
Patch fixing the double free problem (backported from php-snap)

Description of problem:
Reproducible php mbstring module segmentation fault when not supported charset
is used.

Version-Release number of selected component (if applicable):
4.3.9-3.9.1
and above

How reproducible:
Always

1. Install php-mbstring module
2. Execute this php script (through apache or cli):
<?php
  $str = "\357\277\357\277\275\357\277\275\357\277\275\357\277\275";
  $charset = mb_detect_encoding($str , "WINDOWS-1255,ASCII");
  echo "detect $charset\n";
  $str = mb_convert_encoding($str, "UTF-8", $charset);
  echo "convert %str\n";

3. 

Actual result:
PHP Warning:  mb_detect_encoding(): Illegal argument in - on line 3
Content-type: text/html

detect UTF-8
convert %str
*** glibc detected *** double free or corruption (fasttop): 0x00000000008c8b00 ***
Aborted


Expected result:
PHP Warning:  mb_detect_encoding(): Illegal argument in - on line 3
Content-type: text/html

detect UTF-8
convert %str

Additional info:
Php bug report: http://bugs.php.net/bug.php?id=47245