Secure setuid root shell scripts for Linux?

Secure setuid root shell scripts for Linux?

Post by Mike Dowli » Fri, 24 Mar 1995 01:54:07

The perl configure scripts asks if setuid root shell scripts are secure for
linux, and indicates that it suspects otherwise.  Does anyone know if the are
secure?  Perhaps sombody could explain the problems?  The configure script
checks for /dev/fd, which, for linux, has something to do with fooling dull
programs to read from standard input and write to standard output when they
otherwise would refuse to do so.  Is there a connection?

                        Mike Dowling
High-tech Germany presses inexorably on towards fulfilling its great dream of
establishing an electronic mini-crawlway before the end of the next century.


1. Safe setuid-root shell script?

I'm a relative newbie working with a home network connected to the Internet.
I have a very simple shell script that simply sends a signal to mgetty to
force it to pick up the phone for an incoming call (sends it a SIGUSR1 using
killall). The rest of my family may need to use it when I'm not around, but
I don't want to give them the root password. Is it possible to make a shell
script act like a setuid-root program, and do it safely? (I'm hardly about
to let killall be setuid root ... :-) )

Thanks for any help.

jyrinx at mindspring dot com

P.S. The necessity of the script is rather complicated; in essence, I'm
creating a modem-to-modem connection from a Sega Dreamcast to the Linux box,
and this requires manual answering on the Linux-box end. I'm working from
instructions, and have never heard of an alternative way about it (and I
have looked), since the Dreamcast modem doesn't support leased-line mode.

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