Self assigned IP address
A self assigned IP address suggests that your system did not receive an IP address from a DHCP or similar protocol.  As Otto Andy Heiskanen mentions, restarting the DHCP server (by rebooting the router) can solve this issue often.  However you mention your Linux environment does get an IP address, which could point at a different cause.  You also mention that you are not allowed to access the router's settings: are you able to physically access it to pull the power plug?

If you can't access it physically, I recommend you compare the settings in the Linux environment with the settings in OS X.  Is the Linux environment getting an assigned IP address, or is it a fixed IP address?  Perhaps your linux environment is using a MAC address that is different from your physical MAC address?  Maybe there is some newly configured MAC address filtering enabled on the router?