Script Question

[Binu Raj]

Hi All

I have a scripting question.

I have to run this shell script as a normal user but have to insert couple of entries
into the /etc/services file where this user does not have the write access.

One of the requirement is that it should not be interactive. So I thought I could read the super
user username and password as arguments to the script and call "su" and pass it on to it.
But I have no idea how to pass the password to su non interactively.

Can you please help me?

Thanks in advance.

Regards

Binu

[Tom Geudens · Accepted solution]

Hi Binu,
Passing superuser username/password to a script ... not a good idea !

You should use sudo for this (http://www.courtesan.com/sudo/)

Make a script that changes the services-file, allow the user to execute this script as root through sudo ... and you're set.

Hope this helps,
Tom Geudens

[Radim Jarosek]

Hi,

try to have a look at program "expect".

http://hpux.connect.org.uk/hppd/hpux/Tcl/expect-5.38/

HTH

Radim

[Ralph Grothe]

You shouldn't pass root's password to processes at all.

The probably easiest, and with greatest control solution is the mentioned editing via sudo.

Another maybe could be to make an access control list (ACL) for /etc/services which gives the script executing uid write permissions (but maintaining ACLs can be problematic, especially with backups).

Yet another possibility could be to script something that starts execution as euid == 0, then forks off a child that su's to the respective uid, and let the child do what needs to be done under this uid.
Then when it comes to updating /etc/services this could be handled by the parent process that as euid == 0 has ultimate control.

[Niraj Kumar Verma]

Hi ,

you can also make use of stiky bit

rwS------ and change the owner of the file to root ..

But be careful ... Its a risky business .. :)

-Niraj

[Niraj Kumar Verma]

Hi ,

you can also make use of stiky bit

rwS------ and change the owner of the file to root ..

But be careful ... Its a risky business .. :)

-Niraj

[Michael Kelly_5]

Binu,
as far as I'm aware you cannot pass a password to su as an argument.
This is a (security) feature not a bug.
The same is true for the passwd command as well.

In addition to the possible solutions provided earlier you might look into creating a new group (e.g. serupd). Change the group on /etc/services to serupd and change the mode to 775. Put your user in that group and you are done.
Alternatively, you might like to look into Access Control Lists. This will give you a greater level of granularity than the 'standard' owner/group/other permissions
See 'man 5 aclv' for details.
If your root volume is a VxFS version 4 filesystem then it supports ACLs
It is also possible to upgrade earlier versions to version 4 (but I have no experience of doing this).

HTH,
Michael.

[Donny Jekels]

Binu,

I do something similar, and got it working with sudo.

Take care
Donny

[Caesar_3]

Hello!

Best is to run the part that you need to do
as a root with program called sudo
that run with root priv. the wanted commands.

Download from:
http://hpux.connect.org.uk/hppd/hpux/Sysadmin/sudo-1.6.6/

Caesar

[RAC_1]

you can do that with sudo.

Run your script with sudo, it will be run with root user as it's owner. Setting setuid bit is riksy business.