Dropping Root Permissions In Python

Question

I'd like to have a Python program start listening on port 80, but after that execute without root permissions. Is there a way to drop root or to get port 80 without it?

Answer 1

You won't be able to open a server on port 80 without root privileges, this is a restriction on the OS level. So the only solution is to drop root privileges after you have opened the port.

Here is a possible solution to drop root privileges in Python: Dropping privileges in Python. This is a good solution in general, but you'll also have to add os.setgroups([]) to the function to ensure that the group membership of the root user is not retained.

I copied and cleaned up the code a little bit, and removed logging and the exception handlers so it is left up to you to handle OSError properly (it will be thrown when the process is not allowed to switch its effective UID or GID):

import os, pwd, grp  def drop_privileges(uid_name='nobody', gid_name='nogroup'):     if os.getuid() != 0:         # We're not root so, like, whatever dude         return      # Get the uid/gid from the name     running_uid = pwd.getpwnam(uid_name).pw_uid     running_gid = grp.getgrnam(gid_name).gr_gid      # Remove group privileges     os.setgroups([])      # Try setting the new uid/gid     os.setgid(running_gid)     os.setuid(running_uid)      # Ensure a very conservative umask     old_umask = os.umask(077)