non-superuser chown(2)s considered harmful

Bob Goudreau goudreau at larrybud.rtp.dg.com
Wed Dec 12 04:31:23 AEST 1990


In article <5733 at labtam.labtam.oz>, iand at labtam.labtam.oz (Ian Donaldson) writes:
> johnl at iecc.cambridge.ma.us (John R. Levine) writes:
> >Does anyone really do quota accounting by the UID of the file?
> >Consider the following scenario: User A creates a large file.
> >User B links to it.  User A then deletes the original link.  If
> >you charge by uid, user A is charged for the file even though she
> >has no control over it any more, and might not even be able to see
> >that it exists, depending on B's directory protections.
> 
> This is a silly argument.  For user B to write to the file, he must
> have been granted permission by user A.  Thus it is user A's
> responsibility in the first place that the subsequent space charging
> is against him.

So who said anything about writing?  Most of the files that I access
on a daily basis are read or executed, but not written.  Consider the
case of user A's file above.  It could be an X Windows application
program (which tend to be rather large unless shared libraries are
used).  User B could get plenty of use out of that file without ever
needing to write to it.

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