Hard Links between UNIX Utility Programs

Eric Schnoebelen egs at killer.DALLAS.TX.US
Fri Aug 5 01:25:05 AEST 1988


In article <153 at ispi.UUCP> jbayer at ispi.UUCP (id for use with uunet/usenet) 
writes:
>
>Another workable solution is to do the following steps:
>
>	1.	Move the programs you want to restrict to a directory
>			readable only by the super user.
>	2.	Create a shell script for each type of call for each program
>	3.	Make the shell script executable by everyone.
>	4.	Make the owner of the shell script the super user
>	5.	Set the user bit for the shell script (chmod u+s name)

 	Over in comp.unix.wizards they are having a nice little
discussion about setuid shell scripts, and several people have shown how
they are a larger security hole than the programs being discussed here.

	( see comp.unix.wizards for examples )

	A better choice for this solution might be to write small 'wrapper'
programs, and set the suid bit on them.

>Now no matter how someone calls the shell script the program will still
>be called using the correct name.
>
>Jonathan Bayer
>Intelligent Software Products, inc.
>19 Virginia Ave.
>Rockville Centre, NY   11570
>uunet!ispi!jbayer

	Eric Schnoebelen
	John W. Bridges & Associates, Inc.
	Lewisville, Tx.   75067
	u-word!egs at killer.dallas.tx.us



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