[FWP] Re: Puzzle - Temp file creation

[Todd Larason <jtl@molehill.org>]

On 14 July 99, Brian L. Matthews wrote:
> Hope your scripts are never run under modperl or the like, or you never
> want to create more than one temp file in a script. And that *every other
> script* that could be running on the same machine is well-behaved.

And the most important condition: that nobody is being malicious.

Many many programs are vulnerable to attacks that look something like:
for ($pid = $$+10; $pid < $$+100; $pid++) {
  for ($time = time(); $time < time() + 60; $time++) {
    link "/important/file/attackee/has/write/access/to","/tmp/tmp.$pid.$time";
  }
}

and waiting for the user to run the program.  If it's setuid, you don't
even have to wait, you can run it - but even if it isn't, you only have to
do this at the right time *once*.


==== Want to unsubscribe from Fun With Perl?  Well, if you insist...
==== Send email to <fwp-request@technofile.org> with message _body_
====   unsubscribe