Sites are not Isolated - sites have access to one another

[RichardAnderson]

Describe the bug
Deployed sites on a single server do not have the option to run on a different user account (all run on vito), therefore, one compromised site means that all sites are potentially compromised. Sites should be able to be isolated, and therefore run under separate users accounts.

To Reproduce
Steps to reproduce the behavior:

1. Create a PHP application site (site 1)
2. Create a file called "secrets.php", and store a secret in a variable
3. Create a PHP application site (site 2)
4. Upload a remote file editor to site 2
5. Browse to secrets.php from site 1 via the deployed script on site 2
6. See the secret values from site 1 from site 2

Expected behavior
Unable to access files from other sites

Screenshots

Additional context
N/A

[RichardAnderson]

Solution for this, would be to create a new user for a deployed site (or have the option to), and then complete the following actions:

1. Create a new User

export DEBIAN_FRONTEND=noninteractive
sudo useradd -p $(openssl passwd -1 password) user
sudo mkdir /home/user
sudo mkdir /home/user/logs
sudo mkdir /home/user/tmp
sudo usermod -a -G user vito
sudo chown -R user:user /home/user
sudo chmod -R 770 /home/user

2. Create a new PHP FPM pool file in /etc/php/{version}/fpm/pool.d/{user}.conf

[{user}]
user = {user}
group = {user}

listen = /run/php/php-fpm-{user}.sock
listen.owner = vito
listen.group = vito
listen.mode = 0660

pm = dynamic
pm.max_children = 5
pm.start_servers = 2
pm.min_spare_servers = 1
pm.max_spare_servers = 3
pm.max_requests = 500

php_admin_value[open_basedir] = /home/{user}/:/tmp/
php_admin_value[upload_tmp_dir] = /home/{user}/tmp
php_admin_value[session.save_path] = /home/{user}/tmp

; Optional but recommended security settings
php_admin_value[display_errors] = off
php_admin_value[log_errors] = on
php_admin_value[error_log] = /home/{user}/logs/php_errors.log

3. Update the nginx configuration file:

fastcgi_pass unix:/run/php/php-fpm-{user}.sock;

The site is then isolated, so even if one site is compromised, it does not effect any other sites. The Vito user still has full access. And deploy scripts should run as the isolated user.

Example below, the script above can no longer see any folders user it's /home/user directory.

[RichardAnderson]

Started the PR.. But more work is required. #431