3.3.1 questions & complaints

[Thomas Mitchell]

In article <1990Sep27.192121.18059 at odin.corp.sgi.com> jweldon at sgi.com (Jack P. Weldon) writes:
* In article <1990Sep26.174852.1344 at ux1.cso.uiuc.edu> wsherman at newton.ncsa.uiuc.edu (William Sherman -Visualization) writes:
* >I'll ask the question before I lose my audience.  With the new method
* 
* > [X startup question deleted--sorry]
* 
* >Okay, my first complaint is about something I'm sure SGI considers
* >a "feature."  I have some shell scripts
                            ^SUID


* 
* In 3.3, there is a flag to allow suid shell scripts which is shipped
* "off" for security reasons. Edit /usr/sysgen/master.d/kernel and change
* the line "int nosuidshells = 1;" to 0. Then run /etc/init.d/autoconfig
* and reboot (or use lboot if you wish--both build a kernel).  Needless to
* say you must be root to do this...And YES, it *is* a feature, not a bug.

Better to write a 'c' program and make it SUID.  It can
(should) be very simple.  Just issue a "system()" call to do
exactly what you wish no more no less.  Do read the  book
"UNIX System Security"   by Patrick H. Wood and Stephen G. Kochan
Hayden Book Company   ISBN 0-8104-6267-2

The program can have an access list, keep track of who what
when, what is mounted etc.

Of course if you are the only user and not on a network
turn the bit off in the kernel as above.  Shell scripts
are much shorter than 'c' programs.

Compare:

 #!/bin/sh
 echo '\0220'1.y$1'\0234'

With the size of a 'c' program to set the title bar of a
'wsh' window.


--
--
  Thomas P. Mitchell   --  mitch at sgi.com  or mitch%relay.csd at sgi.com
	"All things in moderation; including moderation."