ANSWER:

Answering the question in your subject: OpenSuSE uses the traditional Unix umask setting, instead of the Debian-inspired one adopted by some other Linux distributions.

Editing /etc/login.defs should be sufficient to change it; this will not affect users currently logged in, nor is there any way for you to force such a change to programs that are currently running. It will also not affect users who have overridden it in their ~/.profile (or .bash_profile, .login, etc. as per their shell).

useradd is not involved with this; it is a per-process setting and the default is set during login (hence login.defs and not /etc/default/useradd).

by geekosaur from http://unix.stackexchange.com/questions/37195