I ran into this weird issue when trying to implement CloudFlare on a Magento 1.7.0.2.
The SSL setup is right with CloudFlare, however, every time the site tries https protocol (during checkout/admin area), a SSL redirect loop occurs.
The problem can be solved by adding the following line in .htaccess
############################################ ## FOR NGINX, LIGHTTPD, VARNISH OR ANY OTHER REVERSE PROXY TO APACHE SetEnvIf X-Forwarded-Proto https HTTPS=on
http://www.wecode.com.au/magento/cloudflare-magento-ssl-redirect-loop/