[SOLVED] Run executable file from a different user

Issue

While creating an rpm spec file I have created a new user and group in the %pre section. This new user does not however have permission to login from from shell for security purposes. Now when I install the rpm this new user is successfully created. However, I wish to start the installed rpm service with the newly created user. Currently I simply write; 'filePath/file.exe file.cfg' to execute the file.exe with its configuration file i.e. file.cfg in my 'init.d' file to start the service. How can I modify this command to start the same service but with the user that I created while installing the rpm? Basically I want to execute the program in my init.d file but through a different user, like I would have done with sudo if my required user was the super user. Any feedback will be highly appreciated.

Solution

Your initial starting point both for installing the rpm and for running the service is privileged. For instance, on my CentOS 6 machine, I see in /etc/passwd

games:x:12:100:games:/usr/games:/sbin/nologin

but running as root, I can do this:

$ sudo -u games /bin/sh
sh-4.1$ echo $PATH
/sbin:/bin:/usr/sbin:/usr/bin
sh-4.1$ id
uid=12(games) gid=100(users) groups=100(users) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
sh-4.1$ cd
sh-4.1$ pwd
/usr/games

In your service script, you can use sudo to run a given process as another user (though a quick check of the same machine does not show this being done).

@msuchy points out that runuser may be preferable. I see that this is relatively recent (according to Ubuntu runuser command?, appeared in util-linux 2.23 -- lacking a date makes release notes less than useful...). The oblique comments in its documentation about PAM make it sound as if this circumvents some of the security checks. Perhaps someone has a better comment about that.

Answered By - Thomas Dickey

Answer Checked By - David Goodson (WPSolving Volunteer)