From: "Iñaki Baz Castillo" <ibc@...>
Date: 2009-12-13T02:06:43+09:00
Subject: Re: How to make a ruby program tu run unser other user:group different than root

El Sábado, 12 de Diciembre de 2009, Iñaki Baz Castillo escribió:

> > Maybe you like to copy that:
> > 
> > http://bertram-scharpf.homelinux.com:8808/doc_root/bs-ruby-3.0/rdoc/class
> >e s/Kernel.src/M000100.html
> 
> Really annoying. however I've found an issue with group permissions when
>  doing Kernel#su. I must to investigate it a bit more.

Let me explain it:

- My home "/home/ibc" has these owner/group and permissions:

  drwxr-x---  ibc ibc_grp  /home/ibc/

- Other user "alice" belongs to group "ibc_grp" group so "alice" user can read 
into /home/ibc:

  ~# whoami
  alice
  ~# cd /home/ibc
  ~# echo $?
  0
    
- Now I start a irb session with root user, load "fileutils" and your 
"kernel#su" Ruby file.

- I do "su" to become "alice:alice" and try to enter in /home/ibc, but it 
fails:

  irb> su "alice", "alice" do Dir.chdir("/home/ibc") ; end
  (irb):9:in `chdir': Permission denied - /home/ibc (Errno::EACCES)
        from (irb):9:in `block in irb_binding'
        from /PATH_TO/kernel.rb:7:in `block in su'

- It also doesn't work even setting "root" as group (same error).



kernel.rb:
-------------
module Kernel

  def su u, g = nil
    if block_given? then
      pid = fork {
        su u, g
        yield       <--- line 7
      }
      _, status = Process.waitpid2 pid
      return status
    end
    uid = case u
      when Fixnum then
[...]
-------------


Is it an issue in your code or in fileutils gem?

Thanks a lot.



-- 
Iñaki Baz Castillo <ibc@aliax.net>