Red Hat Bugzilla – Bug 79868
define STDIN dumps core - Segmentation Fault
Last modified: 2007-04-18 12:49:06 EDT
From Bugzilla Helper: User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0) Description of problem: If executed from a shell prompt. The following code fragment dumps core: #!/usr/bin/php <? define('STDIN',fopen("php://stdin","r")); ?> This has been tested with PHP Version 4.1.2 on a fully patched up: Red Hat Linux release 7.0 (Guinness) Kernel 2.2.19-7.0.16 on an i686 and: Red Hat Linux release 7.3 (Valhalla) Kernel 2.4.18-3 Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1. create the three line script 2. ./scriptname 3. Segmentation fault (core dumped) OR Segmentation fault Actual Results: Segmentation fault Additional info: My scripts are broken. I don't know of a workaround. Does anybody know of a way to capture STDIN without core dumping? Core Dumps = Potential for exploit.
Removing security status, this isn't a security issue. A segmentation fault you cause by crashing a program that is running as yourself isn't a vulnerability.
Thanks for the quick reply. However, if this script is called from a webpage (php is after all a web scripting language), and it creates a segmentation fault, then isn't there the possibility that this could become a remote exploit? Not a root exploit, since Apache no longer runs as root, but at least to the privlege level of the webserver (Apache)? Could a hosting client ftp the example script to a server and possibly obtain Apache privleges by running the script from a browser? Is this a security issue? Thanks again for the prompt reply. I will let you be the judge.
I just finished a compile of PHP 4.2.2 from the RH 8.0 distribution, and it does not core dump. I copied the executable to /usr/bin/php422, and I call it explicitly from my scripts. This is a satisfactory workaround for me. You can go ahead and close this bug with the usual "Fixed in Rawhide".
Works for me in 8.0 I agree its security since hosting sites for example may allow secure php stuff but this might allow shell access. Until we know why it crashes I think its a bug