Protecting against downloads

[Leslie Mikesell]

In article <1990Sep20.153105.28394 at naitc.naitc.com> karl at bbs.naitc.com (Karl Denninger) writes:

>I hope you don't allow "vi" access, or you have the bbs in a "chroot"ed area
>with no backlinked files (ie: no linked files between the areas).

What is the danger of linked files if the users don't have write permssion
to any of them?  It takes a non-trivial amount of baggage to make vi
happy (at least on modern SysV it wants the shared libs, all of
/usr/lib/terminfo/*/*, TMPDIR, plus the shell and whatever tools you
need for paragraph reformatting, sorting and the like).  Too bad we
don't have read-only symlinks.

>Without source code to "vi" there is NO WAY to prevent this.  Believe me.  
>I had this rather graphically illustrated to me once; it's a flaw in the
>way vi works.

Actually it's a feature of the way unix works - all the tools expect to
be able to include all the others. 

Les Mikesell
  les at chinet.chi.il.us