Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:105961
Return-Path: <erik@coretech.se>
Delivered-To: mailing list internals@lists.php.net
Received: (qmail 63103 invoked from network); 17 Jun 2019 19:52:00 -0000
Received: from unknown (HELO supernova.coretech.se) (213.134.98.20)
  by pb1.pair.com with SMTP; 17 Jun 2019 19:52:00 -0000
Received: by supernova.coretech.se (Postfix, from userid 1000)
	id DBA914A004; Mon, 17 Jun 2019 19:10:04 +0200 (CEST)
Received: from localhost (localhost [127.0.0.1])
	by supernova.coretech.se (Postfix) with ESMTP id D478C80D5103
	for <internals@lists.php.net>; Mon, 17 Jun 2019 19:10:04 +0200 (CEST)
Date: Mon, 17 Jun 2019 19:10:04 +0200 (CEST)
X-X-Sender: elu@supernova.coretech.se
To: internals@lists.php.net
Message-ID: <alpine.LRH.2.21.1906171908350.27190@supernova.coretech.se>
User-Agent: Alpine 2.21 (LRH 202 2017-01-01)
MIME-Version: 1.0
Content-Type: text/plain; format=flowed; charset=US-ASCII
Subject: [PATCH] Add configuration value to enable/disable stack trace
 logging
From: erik@coretech.se (Erik Lundin)

Background:
The latest version of PHP seems to handle fatal errors as exceptions which 
results in stack traces being logged. Stack traces can potentially contain 
sensitive information and should not be logged in a production 
environment.

Test code:
<?php
function handle_password($a) {
         does_not_exist();
}
handle_password('s3cretp4ssword');

PHP 5.4.16:
Jun 17 15:58:01 server php[29650]: PHP Fatal error:  Call to undefined 
function does_not_exist() in /var/www/html/index.php on line 3

PHP 7.4 (dev):
Jun 17 15:58:01 server php[18159]: PHP Fatal error:  Uncaught Error: Call 
to undefined function does_not_exist() in 
/var/www/html/index.php:3#012Stack trace:#012#0 
/var/www/html/index.php(5): handle_password('s3cretp4ssword')#012#1 
{main}#012  thrown in /var/www/html/index.php on line 3

Suggested patch:
Add a configuration value to be able to prevent exceptions from logging 
stack traces.

log_exception_trace = On/Off

It would be optimal to have this disabled as default as novice 
administrators would perhaps not be aware that this information would be 
logged. For debugging purposes it would be helpful to be able to enable 
this but maybe the default value should be set conservatively to minimize 
unnecessary problems?

I've added this configuration value in Zend/zend.c as the exception 
message is compiled in Zend/zend_exceptions.c. Adding it to main/main.c 
would change the scope from zend_compiler_globals to php_core_globals and 
I guess that you wouldn't want to mix them?

Link to pull request: https://github.com/php/php-src/pull/4281

Regards, Erik Lundin