Executing sudo from ruby

hi,
I wanna execute in a script of mine commands like: "sudo apt-get clean" or "sudo nano /etc/X11/xorg.conf". The difference is:

The first command needs to be executed without influence to the main process of the ruby scipt. It should simply be started as a second process totally independent from the ruby-script which invokes it.
I think system("sudo apt-get clean") would be the right command.

The second command should be this way that it is the only one after it has been executed. So the ruby-script should be stopped and therefor in the same console nano should be opened.
I think exec("sudo nano /etc/X11/xorg.conf") would be the right command.

But my problem is the password of sudo? How can I make my ruby-scipt give the password to sudo so I don't have to give it in every time?

···

--
greets

                     one must still have chaos in oneself to be able to give birth to a dancing star

Hardcoding passwords is a very, very, very, very bad idea.

If you really need to do this - and it's very likely that there's a better,
safer way to do it, but there's not enough information given on what you're
actually trying to achieve - read up on sudo and how you can use its
configuration files to grant users or groups the ability to run particular,
selected commands via sudo without requiring a password.

"man sudoers" should be a pretty good start.

···

-----Original Message-----
From: anansi [mailto:kazaam@oleco.net]
Sent: Wednesday, June 13, 2007 4:20 AM
To: ruby-talk ML
Subject: executing sudo from ruby

hi,
I wanna execute in a script of mine commands like: "sudo
apt-get clean"
or "sudo nano /etc/X11/xorg.conf". The difference is:

The first command needs to be executed without influence to
the main process of the ruby scipt. It should simply be
started as a second process totally independent from the
ruby-script which invokes it.
I think system("sudo apt-get clean") would be the right command.

The second command should be this way that it is the only one
after it has been executed. So the ruby-script should be
stopped and therefor in the same console nano should be opened.
I think exec("sudo nano /etc/X11/xorg.conf") would be the
right command.

But my problem is the password of sudo? How can I make my
ruby-scipt give the password to sudo so I don't have to give
it in every time?

--
greets

                     one must still have chaos in oneself to
be able to
give birth to a dancing star

anansi wrote:

hi,
I wanna execute in a script of mine commands like: "sudo apt-get clean" or "sudo nano /etc/X11/xorg.conf". The difference is:

The first command needs to be executed without influence to the main process of the ruby scipt. It should simply be started as a second process totally independent from the ruby-script which invokes it.
I think system("sudo apt-get clean") would be the right command.

The second command should be this way that it is the only one after it has been executed. So the ruby-script should be stopped and therefor in the same console nano should be opened.
I think exec("sudo nano /etc/X11/xorg.conf") would be the right command.

But my problem is the password of sudo? How can I make my ruby-scipt give the password to sudo so I don't have to give it in every time?

Set NOPASSWD in your sudoers file for the given commands, eg.:

sudoeruser ALL=(ALL) NOPASSWD: /usr/bin/nano,/usr/bin/apt-get

Morten

I am not so clear on what you are asking here, but you can perhaps give a
password to sudo via stdin.
Here's a line from "man sudo":
-S The -S (stdin) option causes sudo to read the password from the
standard input instead of the terminal device.

To open a pipe to a subprocess, see IO.popen, example near the bottom of
this page:
http://www.rubycentral.com/book/tut_threads.html

I can't comment on the safety of doing this, but it's surely not the worst
way to send a password.

Les

···

On 6/13/07, anansi <kazaam@oleco.net> wrote:

hi,
I wanna execute in a script of mine commands like: "sudo apt-get clean"
or "sudo nano /etc/X11/xorg.conf". The difference is:

The first command needs to be executed without influence to the main
process of the ruby scipt. It should simply be started as a second
process totally independent from the ruby-script which invokes it.
I think system("sudo apt-get clean") would be the right command.

The second command should be this way that it is the only one after it
has been executed. So the ruby-script should be stopped and therefor in
the same console nano should be opened.
I think exec("sudo nano /etc/X11/xorg.conf") would be the right command.

But my problem is the password of sudo? How can I make my ruby-scipt
give the password to sudo so I don't have to give it in every time?

--

greets

                     one must still have chaos in oneself to be able to
give birth to a dancing star

--
I always thought Smalltalk would beat Java, I just didn't know it would be
called 'Ruby' when it did.
-- Kent Beck

anansi wrote:

hi,
I wanna execute in a script of mine commands like: "sudo apt-get clean" or "sudo nano /etc/X11/xorg.conf". The difference is:

The first command needs to be executed without influence to the main process of the ruby scipt. It should simply be started as a second process totally independent from the ruby-script which invokes it.
I think system("sudo apt-get clean") would be the right command.

The second command should be this way that it is the only one after it has been executed. So the ruby-script should be stopped and therefor in the same console nano should be opened.
I think exec("sudo nano /etc/X11/xorg.conf") would be the right command.

But my problem is the password of sudo? How can I make my ruby-scipt give the password to sudo so I don't have to give it in every time?

Wouldn't a setuid root script that actually calls the executable you're aiming at do what you need here?

···

--
Alex

thanks for your answers but that are no options here. I know hardcoded passes are in generally a bad idea but it's really needed here and safe. This is just a personal code on an offline pc with a highly encrypted partitions...

Is there no way to give the pass as argument or pipe it or kind if that? But as said I need a technique working in both cases mentioned in the first post.

Morten wrote:

···

anansi wrote:

hi,
I wanna execute in a script of mine commands like: "sudo apt-get clean" or "sudo nano /etc/X11/xorg.conf". The difference is:

The first command needs to be executed without influence to the main process of the ruby scipt. It should simply be started as a second process totally independent from the ruby-script which invokes it.
I think system("sudo apt-get clean") would be the right command.

The second command should be this way that it is the only one after it has been executed. So the ruby-script should be stopped and therefor in the same console nano should be opened.
I think exec("sudo nano /etc/X11/xorg.conf") would be the right command.

But my problem is the password of sudo? How can I make my ruby-scipt give the password to sudo so I don't have to give it in every time?

Set NOPASSWD in your sudoers file for the given commands, eg.:

sudoeruser ALL=(ALL) NOPASSWD: /usr/bin/nano,/usr/bin/apt-get

Morten

--
greets

                     one must still have chaos in oneself to be able to give birth to a dancing star

the thing is that everything needs to be done by this script and no further command. So can an app give it self the root uid at runtime?

Alex Young wrote:

···

anansi wrote:

hi,
I wanna execute in a script of mine commands like: "sudo apt-get clean" or "sudo nano /etc/X11/xorg.conf". The difference is:

The first command needs to be executed without influence to the main process of the ruby scipt. It should simply be started as a second process totally independent from the ruby-script which invokes it.
I think system("sudo apt-get clean") would be the right command.

The second command should be this way that it is the only one after it has been executed. So the ruby-script should be stopped and therefor in the same console nano should be opened.
I think exec("sudo nano /etc/X11/xorg.conf") would be the right command.

But my problem is the password of sudo? How can I make my ruby-scipt give the password to sudo so I don't have to give it in every time?

Wouldn't a setuid root script that actually calls the executable you're aiming at do what you need here?

--
greets

                     one must still have chaos in oneself to be able to give birth to a dancing star

anansi wrote:

the thing is that everything needs to be done by this script and no further command. So can an app give it self the root uid at runtime?

After a little experimentation (on Ubuntu), it would seem that the only way to get my suggestion to work is by creating a setuid link to the ruby binary, and using that to run the script. That's just as insecure as keeping a password in a file, so I take back my suggestion entirely.

A slightly less unsafe method (but still rather iffy) would be to create a public key for the root account, and do everything over SSH. That way you can arrange to only need to authenticate once per session (or, if you really want to play fast and loose, leave the private key with an empty passphrase). I don't know if that helps at all...

···

--
Alex

Alex Young wrote:

anansi wrote:

hi,
I wanna execute in a script of mine commands like: "sudo apt-get clean" or "sudo nano /etc/X11/xorg.conf". The difference is:

The first command needs to be executed without influence to the main process of the ruby scipt. It should simply be started as a second process totally independent from the ruby-script which invokes it.
I think system("sudo apt-get clean") would be the right command.

The second command should be this way that it is the only one after it has been executed. So the ruby-script should be stopped and therefor in the same console nano should be opened.
I think exec("sudo nano /etc/X11/xorg.conf") would be the right command.

But my problem is the password of sudo? How can I make my ruby-scipt give the password to sudo so I don't have to give it in every time?

Wouldn't a setuid root script that actually calls the executable you're aiming at do what you need here?

If you aren't worried about security, you might try expect. Using expect you can define responses to prompts, e.g. responding with the password.

···

On 13-Jun-07, at 8:40 AM, anansi wrote:

the thing is that everything needs to be done by this script and no further command. So can an app give it self the root uid at runtime?

----
Bob Hutchison -- tumblelog at <http://www.recursive.ca/so/&gt;
Recursive Design Inc. -- weblog at <http://www.recursive.ca/

                                -- works at <http://www.recursive.ca/&gt;

To run your editor, you'd probably need to use the -t option of ssh to
alloate a pseudo-tty.

You can configure the SSH keypair so that it's only authorized to run a
couple of specific commands, which should help with security. Also, be
sure to use "nano -R" so that the user can't edit other files.

The exec() call is wrong, because that replaces the running ruby script
with a different process, and the ruby script can't terminate. system()
is correct for the second case too.

···

On Wed, 13 Jun 2007 22:19:16 +0900, Alex Young wrote:

anansi wrote:

the thing is that everything needs to be done by this script and no
further command. So can an app give it self the root uid at runtime?

After a little experimentation (on Ubuntu), it would seem that the only
way to get my suggestion to work is by creating a setuid link to the
ruby binary, and using that to run the script. That's just as insecure
as keeping a password in a file, so I take back my suggestion entirely.

A slightly less unsafe method (but still rather iffy) would be to create
a public key for the root account, and do everything over SSH. That way
you can arrange to only need to authenticate once per session (or, if
you really want to play fast and loose, leave the private key with an
empty passphrase). I don't know if that helps at all...

--
Ken Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/

thanks for the hint but I only found this about expect:http://www.ruby-doc.org/stdlib/libdoc/pty/rdoc/classes/IO.html#M001710

. Is there any better doc or examples for this ?

···

--
greets

                     one must still have chaos in oneself to be able to give birth to a dancing star

Alex Young wrote:

anansi wrote:

the thing is that everything needs to be done by this script and no
further command. So can an app give it self the root uid at runtime?

After a little experimentation (on Ubuntu), it would seem that the only
way to get my suggestion to work is by creating a setuid link to the
ruby binary, and using that to run the script. That's just as insecure
as keeping a password in a file, so I take back my suggestion entirely.

A slightly less unsafe method (but still rather iffy) would be to create
a public key for the root account, and do everything over SSH. That way
you can arrange to only need to authenticate once per session (or, if
you really want to play fast and loose, leave the private key with an
empty passphrase). I don't know if that helps at all...

--
Alex

How about running job in a cron under root user.

sudo kcron (in kde) will start kcron in mode where you can schedule a
job to run as any user.

by

TheR

···

--
Posted via http://www.ruby-forum.com/\.

thanks for the hint but I only found this about expect:http://www.ruby-doc.org/stdlib/libdoc/pty/rdoc/classes/IO.html#M001710
. Is there any better doc or examples for this ?

I used the unix version of the command directly. The man page is useful I thought. I've never used the ruby expect classes but imagine that they would be doing something similar.

Cheers,
Bob

···

On 13-Jun-07, at 12:35 PM, anansi wrote:

--
greets

                    one must still have chaos in oneself to be able to give birth to a dancing star

----
Bob Hutchison -- tumblelog at <http://www.recursive.ca/so/&gt;
Recursive Design Inc. -- weblog at <http://www.recursive.ca/

                                -- works at <http://www.recursive.ca/&gt;