mod-auth-shadow

Auth Shadow or mod-auth-shadow is a module for apache (and apache2, sort of) that enables authentication against /etc/shadow. The benefits being that any system user with a password can be authenticated for web_dav, subversion or simply an https server. The only other way to do this is with PAM. That method is dangerous because the apache user (www-data in my case) must be able to read /etc/shadow. Obviously, not a good idea. Auth Shadow accomplishes this safely by using a intermediate program called validate. This works because validate can be owned by root but executable by everyone.