Re: [RFC/PATCH] revoke/frevoke system calls V2

From: Edgar Toernig
Date: Wed Aug 09 2006 - 13:58:18 EST

Alan Cox wrote:
> Ar Mer, 2006-08-09 am 10:41 +0200, ysgrifennodd Edgar Toernig:
> > > If I own the file I can make it a symlink to a pty/tty pair
> > > I can revoke a pty/tty pair
> >
> > With the EIO/EOF behaviour that's not a problem - apps that deal
> > with ttys have to expect that condition.
> Think about it a moment - I can symlink any file to a tty/pty pair so
> any file I own you open might be a tty.

Yes, OK. The EIO/EOF behaviour is fine. Even for regular files it's
not something extraordinary.

> > Hmm... which apps have an open fd on block devices? Usually a
> cdrecord, cd audio players, eject, ....

And killing them is not OK? "fuser -km /dev/cdrom" already covers both
cases, mounted somewhere and opened for special access.

Sorry if I sound a little bit anal. IMO, a generic revoke is a pretty
sharp sword which is given to ordinary users and I have a very uneasy
feeling. They can dig in the innards of other people's processes - a
clean headshot by root is something different ...

Ciao, ET.
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