Configuring user access control in CTA

<!--HTML-->CTA uses access mechanism provided by EOS and adds tape-specific layer. If one of these elements is misconfigured, a user won't be able to read a file, or, on the contrary, unauthorized access can be granted. This talk explains how the combination of the ACL, Unix permissions and mount rules works in CTA. We show which tools we use for the permissions management and what are capabilities and limitations of our system.