Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!rutgers!att!laidbak!daveb
From: daveb@i88.isc.com (Dave Burton)
Newsgroups: comp.lang.perl
Subject: Re: #! troubles
Message-ID: <1990Jan11.000117.7097@i88.isc.com>
Date: 11 Jan 90 00:01:17 GMT
References: <1970@uvaarpa.virginia.edu>
Sender: stevea@i88.isc.com (Steve Alexander)
Organization: Interactive Systems nee Lachman Associates
Lines: 34

In article <1970@uvaarpa.virginia.edu> worley@compass.com writes:
|The *real* solution for this problem is to have the kernel search your
|path when it sees a #!.  Otherwise, you have to be root to install a
|new interpreter in the "standard" place, because the #!'s have the
|interpreter's location hardcoded in.

Assuming the kernel gets your $PATH (which it doesn't, but pretend) -

What happens when the PATH is ".:/bin:/usr/bin", and the
script is suid root? How about:

	$ cd
	$ cat > sh.c
	main()
	{
		setuid(0);
		execl("/bin/sh", "sh", (char *)0);
	}
	^D
	$ cc -o sh sh.c
	$ cat script
	#!sh
	echo oops!
	$ ls -l script
	-rwsr-xr-x  1 root           16 Jul 26 16:19 script
	$ script
	# 

Searching $PATH is definitely NOT for the kernel.

-- Dave Burton
--
Dave Burton
uunet!ism780c!laidbak!daveb