Vagrant folder permissions using nginx
I would load the shared folder with vagrant as the owner and the group and then change the user and the group to vagrant in /etc/php5/fpm/pool.d/www.conf.
To change the user and group in the php-fpm's config, just add these to lines to the end of provision/setup.sh:
sed -i 's/user = www-data/user = vagrant/g' /etc/php5/fpm/pool.d/www.confsed -i 's/group = www-data/group = vagrant/g' /etc/php5/fpm/pool.d/www.confIf this does not help, try to increase the permission of /var/www recursively.