Restrict Port range to a user

Question

On a server with several users I'm looking to reserve port ranges so that only one user has access to a specific port range, IE

user1: 2000-2005
user2: 2006,3003
user3: 1025

In doing so, an application spawned by that user can only access ports allotted to that user. All other ports would fail to bind. Is there a way to do this on a Linux (Ubuntu) server?

Answer 1

I don't know if iptables owner module would help you, it will allow you to apply rules regarding the owner. You could do something like:

iptables -I OUTPUT -m owner --uid-owner=pmartinez -p tcp -m multiport --sports 2000:2005 -j ACCEPT
iptables -I OUTPUT -m owner --uid-owner=pmartinez -j REJECT

That won't avoid binding but it will block all traffic and only allow the specified ports.