Hardening rules for Nginx breaks tinymce

The way I got it working is by adding a rule allowing TinyMCE
followed by a rule denying all php files in the wp-includes directory.

The rule for allowing TinyMCE MUST contains directives connecting Nginx to PHP application server (php5-fpm in my case).
Basically i copied over the directives i had under the location ~ \.php$ block.

So for me the solution looked like this:

# Allowing TinyMCE only
location = /wp-includes/js/tinymce/wp-tinymce.php {
        allow all;
        fastcgi_pass unix:/var/run/php5-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_read_timeout 300s;

}

# Blocking other PHP files in wp-includes
location ~* /wp-includes/.*.php$ {
        deny all;
}