Messages in this thread |  | | | Date | Mon, 17 Jan 2000 19:53:07 -0500 (EST) | | From | Stephen Frost <> | | Subject | Re: Why wrapping PIDs is evil [was 32bit] |
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On Sun, 16 Jan 2000, Pavel Machek wrote:
> > > Sorry, alan. No. Unix is broken with this part. > > > > When you run as root, you run risks and have to be careful. > > No. You can't be carefull. Users have full chance to get you in this case.
Then don't run as root if you're that concerned.
> > thing about Unix is that it wraps pids and does _not_ pick random pids. You shouldn't > > get around to the same pid for at least a reasonable amount of time, unless someone > > is spawning processes _very_ fast. > > But someone probably _is_ spawning processes very fast if they want to > screw you.
There are a number of generally more useful (to the 'evil' one) things that can be done. In any case, perhaps coming up w/ a patch to allow for a 64bit PID, and fixing up everything to use it, while not introducing any new security holes, and fixing every program in existance that uses a pid will do what you want, but I don't see much of a payoff for that much work.
> > > But that's wrong. Pavel may have seen you are going to kill his emacs > > > and may have wrapped pids, killed his emacs himself, and you are now > > > killing _your_ netscape you've just ran. > > > > Erm, too bad that's exactly what _doesn't_ happen under Unix. Your netscape > > you just started will get a new pid, after the latest one taken. No matter if that > > process died or not. > > I forgot to mention: of course _pavel_ is evil and created/killed just > enough processes for PIDs to wrap in bad way.
If _pavel_ is evil, and got lucky enough to manage this, chances are _pavel_ won't be around on that box much longer.
Stephen
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