yast2-auth-client: OS command injection via unsanitized Organizational Unit / dnsHostName in AD join

A OS command injection vulnerability in yast2-auth-client allows an attacker who controls Active Directory configuration values to execute arbitrary commands as root on the configured host. Auth::AuthConf in src/lib/auth/authconf.rb assembles the Samba net ads join, net ads lookup -S and net ads testjoin invocations by interpolating configuration values into a single command string and passing that string to Open3.popen2 / Open3.capture2, which causes Ruby to run it through /bin/sh. The Organizational Unit (ou), dnshostname, AD user name and AD domain name values are neither validated nor shell-quoted.