After installing CentOS 7 I could not connect to any wifi networks as an unprivileged user. I tried to use the KDE network applet on the KDE panel and got a message saying "waiting for authorization" or something very similar and then the connection times out.

Thankfully the solution was simple, after a quick google search.

Open a terminal window in your desktop environment/window manager (you can skip this step, if you do not have any installed);

Switch user to the root user;

Run the following command as the root user;

Replace wifinetworkname with the actual name of the wifi network, you would like to connect to.

Hopefully you should only have to do this once.