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Bug #68986 pointer returned by php_stream_fopen_temporary_file not validated in memory.c
Submitted: 2015-02-05 04:25 UTC Modified: 2015-02-05 08:41 UTC
From: nayana at ddproperty dot com Assigned: laruence
Status: Closed Package: Streams related
PHP Version: master-Git-2015-02-05 (Git) OS: Linux
Private report: No CVE-ID:
 [2015-02-05 04:25 UTC] nayana at ddproperty dot com
Description:
------------
it seems that the pointer returned by php_stream_fopen_temporary_file / php_stream_fopen_tmpfile is not validated prior to use in memory.c in the case where a script is executed in an environment  where the TMPDIR is not writable to the user, it will cause a SIGSEGV.

from the script side any code that utilize php://temp with 2MB+ buffer with the above condition will encounter this issue.


i have fixed the problem on all the calling code in memory.c using php_error_docref, i see that in phar they have handled the condition with zend_throw_exception_ex. i am not in a position to decide which one is best at this time. i think a friendly warning is better than a SIGSEGV at this point :)

i have validated this problem exists on github-master and releases 5.4.37, 5.4.17 

i will post my pull-request in a comment 

Test script:
---------------
#mkdir /tmp/x
#chmod 444 /tmp/x
#export TMPDIR=/tmp/x

$fp = fopen('php://temp', 'r+');
$data = implode('', array_fill(0, (1024 * 1024 * 2), 'A'));
fwrite($fp, $data);




Patches

fix.patch (last revision 2015-02-05 04:29 UTC) by Nayana at ddproperty dot com)

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Pull Requests

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History

AllCommentsChangesGit/SVN commitsRelated reports
 [2015-02-05 08:41 UTC] laruence@php.net
-Status: Open +Status: Closed -Assigned To: +Assigned To: laruence
 [2015-02-05 08:41 UTC] laruence@php.net
The fix for this bug has been committed.

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