It makes no difference as this combo;

root '/path/';
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

open_basedir = '/path/'
doc_root = '/path/'

Next to jailing, this boxes everything in.

With location /.../ '.php' you fine-tune where scripts live which may be run.

I'd leave cgi.force_redirect commented, ea. not set to anything at all.

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