prevent the use of "alternate shell"

[robanybody]

Hi, is there a way to prevent Users from executing a single application instead of running the intended Desktop? I guess it would make sense to have an option in sesman.ini to set the intended behavior.

[evanlinde]

You can edit startwm.sh (specifically the wm_start function) to start a specific desktop.

For example, on CentOS 7, instead of calling the wm_start function, you could add a line like:

. /etc/X11/xinit/Xsession /prog/to/start

where /prog/to/start could be something like /bin/gnome-session or a custom script.

[robanybody]

well that does not prevent a user from runing an "alternate shell" . Looks like startwm.sh would not run if "start a program" option is set to an existing program like usr\bin\lxterminal. By the way my startwm.sh looks like this: #!/bin/sh exec /usr/bin/awesome exit 1

[robanybody]

found the place in code and commented it out: sesman/session.c

            if (s->directory != 0)
           {
              if (s->directory[0] != 0)
               {
                 /* don't do anything 
                  g_set_current_dir(s->directory);
                 */
               }
           }
           if (s->program != 0)
           {
               if (s->program[0] != 0)
               {
                  /* prevent use of alternate shell
                   g_execlp3(s->program, s->program, 0);
                   log_message(LOG_LEVEL_ALWAYS,
                               "error starting program %s for user %s - pid %d",
                               s->program, s->username, g_getpid());
                  */
                   log_message(LOG_LEVEL_ALWAYS,
                               "attention user %s tried to start program %s for - pid %d we don't allow this",
                               s->username, s->program,  g_getpid()); 
               }
           }

works !

[metalefty]

I think removing/commenting out the code that you show is the only solution so far.

[robanybody]

so then this is a feature request :-)

Would be nice to have an option to disable "alternative shell / startup program" via config would be even more great if you could put a default program in config would be super awesome, if you could enter an array of allowed programs

Thanks for the review I was not 100% sure whether "g_set_current_dir (s-> directory);" part of the alternative shell

[metalefty]

I cannot promise to implement it but I stack it feature request.

[lennartS-lfb]

Would you be willing to have a look at a pull request implementing a simple configuration option (alternative 1 as suggested by @robanybody) for this?

[matt335672]

If you submit one, we'll look at it - thanks!

I take it you're thinking of putting an option in sesman.ini?

[lennartS-lfb]

Great to hear :)

Yes, I was thinking about the Security section of the sesman.ini, since the code knows about that config anyway. It won't be this week, but I'll take a stab at it.

[matt335672]

Sounds like a good place.

A couple of thoughts:-

• Name the parameter so it could maybe be expanded to allow alternative 3. Something like "AlternateShellAllowed=yes/no" for now, and we could maybe add "list" in the future. That's off the top of my head - use whatever suits.
• Don't forget the manpage!
• This would be a great change to 0.9.x (if we release another one) as well as devel. Feel free to work on whichever branch you're happiest with, and we'll take care of the other one.

Any questions, come back to me. I'm fairly occupied for a few days now anyway so there's no rush.

[matt335672]

Most importantly, thanks for looking at this!

[matt335672]

Fixed by #2634