Allow php sessions to carry over to subdomains
Solution 1:
Here are 4 options.
Place this in your php.ini:
session.cookie_domain = ".example.com"
Or in your .htaccess:
php_value session.cookie_domain .example.com
Or as the first thing in your script:
ini_set('session.cookie_domain', '.example.com' );
Or in your php-fpm pool configuration for your site:
php_value[session.cookie_domain] = .example.com
Solution 2:
if(isset($_COOKIE['session_id']))
session_id($_COOKIE['session_id']);
Zend_Session::start(); //or session_start();
if(!isset($_COOKIE['session_id']))
setcookie('session_id', session_id(), 0, '/', '.yourdomain.com');
security be damned, if you are as frustrated with incomplete or bad answers as I am, this is your savior. It just works.
Solution 3:
change the session name at the top of the core functions file like
session_name('mysession');
then use the following code into the php page
session_set_cookie_params(0,"/",".example.com",FALSE,FALSE);
setcookie(session_name(), session_id(),0,"/","example.com");
session_start();
finally change the default session name of the subdomain and remove the default cookie in subdomain's core functions file like:
/*default session name*/
session_name("mysession");
/*remove the PHPSESSID and default session name from subdomain's cookie*/
setcookie( "mysession", "",1,"/" );
setcookie( "PHPSESSID", "",1,"/" );
if you continue with using your cookie name as PHPSESSID ,just remove all the functions with
"mysession" string like session_name('mysession'), setcookie( "mysession", "",1,"/" );
then check your browser's existing cookies, just remove all the cookies of domain and subdomain, and repeat the process.
Solution 4:
I know this is quite old - but to further expand on @CTT's suggestion - I needed to add a php.ini file in each sub-directory (that will be executing php code and requires the session) of my subdomain with the following text:
suhosin.session.cryptdocroot=Off
suhosin.cookie.cryptdocroot=Off
I hope this helps (it took me ages to figure this out).