GNU bug report logs - #8117
ln to /tmp is irreversible

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Křištof Želechovski
 <giecrilj <at> stegny.2a.pl>
Subject: bug#8117: closed (Re: bug#8117: ln to /tmp is irreversible)
Date: Sun, 10 Apr 2011 03:59:01 +0000

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Your bug report

#8117: ln to /tmp is irreversible

which was filed against the coreutils package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 8117 <at> debbugs.gnu.org.

-- 
8117: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=8117
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

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From: Bob Proulx <bob <at> proulx.com>
To: Křištof Želechovski <giecrilj <at> stegny.2a.pl>
Cc: 8117-done <at> debbugs.gnu.org
Subject: Re: bug#8117: ln to /tmp is irreversible
Date: Sat, 9 Apr 2011 21:58:48 -0600

Bob Proulx wrote:
> Křištof Želechovski wrote:
> >   1. Find a file in /tmp owned by somebody else and not owned by you.  Say a.txt.
> >   2. { ln a.txt b1.txt; } # you created b.txt based on a.txt
> >   3. {  rm b1.txt; } # error: Operation not permitted.
> 
> Yes this is true.  But this doesn't have anything to do with either
> 'ln' or 'rm' but is instead a behavior associated with Unix
> filesystems and specifically the behavior of the sticky-bit on
> directories.  It is an operating system policy.  Therefore I am
> tagging this as not a bug in the bug tracking system.

There wasn't any further discussion, it is an operating system
filesystem behavior, and so I am closing this bug in the bug tracking
system for coreutils.

Bob

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From: Křištof Želechovski <giecrilj <at> stegny.2a.pl>
To: bug-coreutils <at> gnu.org
Subject: ln to /tmp is irreversible
Date: Fri, 25 Feb 2011 17:54:33 +0100

== To reproduce: ==

  1. Find a file in /tmp owned by somebody else and not owned by you.  Say a.txt.
  2. { ln a.txt b1.txt; } # you created b.txt based on a.txt
  3. {  rm b1.txt; } # error: Operation not permitted.
  4. Go to step 2, replacing b1 by b2, and so on.
(  5. ??? )
(  6. Profit. )

== The conclusion ==
Allowing irreversible operations is a bad thing, and this is not a circumstance where an exception would be appropriate.  The tool ln should not allow the operator to create an entry he cannot delete.

== Workaround ==
Never put anything into /tmp.  Use /tmp/kde-$LOGNAME (or whatever your directory is) instead.

IMHO,
Chris

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