White screen on homepage

[InspectahDeck]

Hello, I need assistance in troubleshooting a blank white page that occurs on the homepage. So the odd thing is, the white screen only occurs if you click on the link to the website from google. If you type in the URL manually, it works just fine. I already checked if it was a case of the www, or https://, and tried all variations, it is simply coming from Google that is causing the issue.

I turned on the PHP flag display_errors, and the screen is still blank white. Now, if I enter in the text "123" at the top of index.php (or any text for that matter), the site will load with PHP Headers already sent messages. So if I trigger a warning or error specifically in PHP, it will output the warning and the rest of the site will still load. The second I remove that "123" from index.php, and try it again, it's a white screen again.

I'm thinking this might be a case of caching, so I cleared the site cache through Advanced > Maintenance, but the blank screen is still occuring.

This seems to have started when we did a well overdue upgrade from CubeCart 4 to latest (6.0.10).

Any ideas are much appreciated

[bsmither]

It is interesting that a recent security vulnerability was tied to arriving at a store from a search engine - generally Google. But CC6010 fixed that.

Please enable PHP's error_logging. Displaying errors is good -- CubeCart does that itself for a brief period, until Cubecart initializes it's own error logging facility. Then Cubecart switches off display_errors.

In Cubecart's admin, view the Manage Hooks, Code Snippets tab. If you find a snippet in the table you do not recognize, delete it.

 

[InspectahDeck]

Thanks for the suggestion. I just checked the Code Snippets tab and there are no code snippets.

[bsmither]

So, let's find out what may be happening.

Please create a file called ini-custom.inc.php, and have as its contents:

<?php
# Custom initialization commands
# Filename: ini-custom.inc.php
# File location: main CubeCart folder

ini_set('memory_limit', '256M');
ini_set('max_execution_time', '60');
ini_set('error_log', 'error_log');
ini_set('log_errors', 'on');

?>

Place this file in CubeCart's main folder.

Have the browser request the homepage of your store. When you get the white screen, then download the error_log you will find in Cubecart's main folder.

[InspectahDeck]

Ok I did this, and it is not displaying any errors in the file. I typed in the address of the site manually and rechecked the error_log, and it only gave me this error, which isn't a fatal error and shouldn't terminate execution of the rest of the page:

PHP Warning:  Stored session data did not match DB record. Session aborted as possible session hijack.