Path: utzoo!utgpu!attcan!lsuc!eci386!clewis
From: clewis@eci386.uucp (Chris Lewis)
Newsgroups: comp.unix.xenix
Subject: Re: Linking directories on Xenix???
Message-ID: <1989Aug21.202833.23597@eci386.uucp>
Date: 21 Aug 89 20:28:33 GMT
References: <1114@ispi.UUCP>
Reply-To: clewis@eci386.UUCP (Chris Lewis)
Organization: R. H. Lathwell Associates: Elegant Communications, Inc.
Lines: 31

In article <1114@ispi.UUCP> jbayer@ispi.UUCP (Jonathan Bayer) writes:
>I have a need to be able to link a directory to another directory.  I
>know that it normally is not possible, but I was wondering if there was
>a way to fool the OS into linking a directory to another?  The problem
>is here because I have a program that for safety's sake must run
>chroot'ed in a directory, but also has to have access to the standard
>/etc directory, and has to be able to create files in /etc that will be
>there later. 
>
>Any ideas?

Getting the files in is easy:

	ln /etc/* /etc/rootdir/etc

Getting them out ain't, though as long as these files aren't deleted,
you could "touch" 'em in /etc and link 'em to /etc/rootdir/etc.
Or simply copy the files back after your special application runs.

Frankly, if you don't trust the program to run without chrooting, I don't
know why you'd trust it enough to have /etc writeable.

Are you concerned about integrity or security?

You could hard "link" (rather than ln) the directory as root, but a 
hostile program might be able to break the chroot by chdir("..")'ing.
-- 
Chris Lewis, R.H. Lathwell & Associates: Elegant Communications Inc.
UUCP: {uunet!mnetor, utcsri!utzoo}!lsuc!eci386!clewis
Phone: (416)-595-5425