Re: Proposal: restrict link(2)

Adam D. Bradley (bradley@cs.unca.edu)
Fri, 13 Dec 1996 14:48:57 -0500 (EST)

Steve VanDevender <stevev@efn.org> wrote:
> Harald Koenig writes:
> > * clobber other user's disk quoatas, disk usage and disk space accounting etc.
>
> No.
>
> $ mkdir tmp; cd tmp
> $ dd if=/dev/zero of=foo bs=1024 count=1024
> 1024+0 records in
> 1024+0 records out
> $ du
> 1030 .
> $ ln foo bar
> $ du
> 1030 .
> $ rm foo
> $ du
> 1030 .

I think you missed the point:

PersonA PersonB
-------- --------
$ quota $ cd
Filesystem blocks [da da da] $ mkdir tmp
[da da da] 100000 [da da da] $ chmod 700 tmp
$ cd ~/tmp $ cd tmp
$ cp somefile.1meg foo
$ ln ~PersonA/tmp/foo .
$ quota [cackles heartlessly]
Filesystem blocks [da da da]
[da da da] 101024 [da da da]
$ rm foo
$ quota
Filesystem blocks [da da da]
[da da da] 101024 [da da da]
$ find /home -user PersonA
[stuff]
find: cannot open < /home/PersonB/tmp >
[stuff]
[scratches head in bewilderment]

Checked this on Digital Unix 4.0, I believe Linux acts the same way...

Perhaps if there was a mechanism for locating inodes that you own, but you
cannot access through the directory structure...(donning flame-retardant
underwear in expectation of "here's one, dummy!" messages)

Adam

--
He feeds on ashes; a deluded mind has led him    Adam Bradley, UNCA Senior
astray, and he cannot deliver himself or say,             Computer Science
"Is there not a lie in my right hand?"   Isaiah 44:20
        bradley@cs.unca.edu       http://www.cs.unca.edu/~bradley      <><