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From: kaih@khms.westfalen.de (Kai Henningsen)
To: linux-kernel@vger.kernel.org
Subject: Re: rm-ing files with open file descriptors
Date: 19 Jan 2002 19:44:00 +0200	[thread overview]
Message-ID: <8HBE1o7mw-B@khms.westfalen.de> (raw)
In-Reply-To: <Pine.GSO.4.21.0201190627310.3523-100000@weyl.math.psu.edu>
In-Reply-To: <a2bk6e$t2u$1@ncc1701.cistron.net> <Pine.GSO.4.21.0201190627310.3523-100000@weyl.math.psu.edu>

viro@math.psu.edu (Alexander Viro)  wrote on 19.01.02 in <Pine.GSO.4.21.0201190627310.3523-100000@weyl.math.psu.edu>:

> On Sat, 19 Jan 2002, Miquel van Smoorenburg wrote:
>
> > This could be hacked around ofcourse in fs/namei.c, so I tried
> > it for fun. And indeed, with a minor correction it works:
> >
> > % perl flink.pl
> > Success.
> >
> > I now have a flink-test2.txt file. That is pretty cool ;)
>
> It's also a security hole.

It may well be one when going via /proc. But is it one when going via a  
(hypothetical) proper flink(2)? If so, why?

Note that every process who has a filehandle open for reading can already  
get at the file contents and write them to a completely new file, and  
every process who has it open for writing can already change its contents  
to everything it likes. So I can see read|write checks on the file handle.  
Also all the usual link(2) checks. What else could be a hole?

MfG Kai

  parent reply	other threads:[~2002-01-19 19:07 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-01-18 21:11 rm-ing files with open file descriptors Doug Alcorn
2002-01-18 21:27 ` Xavier Bestel
2002-01-18 21:28 ` Ken Brownfield
2002-01-19 20:23   ` Rob Landley
2002-01-18 21:49 ` Richard B. Johnson
2002-01-19  0:50   ` Miquel van Smoorenburg
2002-01-19  2:29     ` H. Peter Anvin
2002-01-19 10:57       ` Xavier Bestel
2002-01-19 11:10       ` Miquel van Smoorenburg
2002-01-19 11:28         ` Alexander Viro
2002-01-19 12:01           ` Miquel van Smoorenburg
2002-01-23 12:18             ` Pavel Machek
2002-01-24  9:46               ` Herbert Xu
2002-01-19 17:44           ` Kai Henningsen [this message]
2002-01-20 15:30             ` Richard Kettlewell
2002-01-20 18:21               ` Doug McNaught
2002-01-20 23:10               ` Miquel van Smoorenburg
2002-01-20  3:55           ` Chris Wedgwood
2002-01-19 15:21         ` Horst von Brand
2002-01-19 15:32           ` Mr. James W. Laferriere
2002-01-19 20:26             ` Rob Landley
2002-01-19 17:53           ` Miquel van Smoorenburg
2002-01-20 15:48             ` Horst von Brand
2002-01-19 20:24           ` Rob Landley
2002-01-19 11:15       ` Ville Herva
2002-01-19 12:16       ` Matthias Schniedermeyer
2002-01-19 12:22         ` Xavier Bestel
2002-01-19 12:29           ` Alexander Viro
2002-01-19 12:46             ` Xavier Bestel
2002-01-19 13:18               ` Rogier Wolff
2002-01-19 15:24             ` Horst von Brand
2002-01-19 14:50     ` Horst von Brand
2002-01-20 14:23     ` Remi Turk
2002-01-20 20:02       ` Ville Herva
2002-01-20 20:44         ` Andreas Ferber
2002-01-20 21:08           ` Ville Herva
2002-01-21  9:06             ` Horst von Brand
2002-01-21  9:21               ` Ville Herva
2002-01-18 21:59 ` J Sloan
2002-01-19  4:18 ` Andreas Bombe
2002-01-19 14:51   ` christophe barbé
2002-01-19 18:01     ` Kai Henningsen
2002-01-20  3:43       ` christophe barbé
  -- strict thread matches above, loose matches on Subject: below --
2002-01-18 22:11 Hank Leininger

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