Re: /proc filesystem allows bypassing directory permissions on
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Am Samstag, den 24.10.2009, 01:12 +0400 schrieb Dan Yefimov:
> On 24.10.2009 0:35, Matthew Bergin wrote:
> > doesnt look like the original owner is trying to write to it. Shows it
> > cant, it had guest write to it via the proc folders bad permissions.
> > Looks legitimate
> >
> Please tell me, who issued 'chmod 0666 unwritable_file'? Was that an atta=
cker?=20
> No, that was the owner of 'unwritable_file', nobody else. What the 0666 f=
ile=20
> mode means? It means, that everybody can write to the file, can't he? So =
why do=20
> you believe that pretension legitimate?
Well, at first I would say this might definitely somewhat unexpected.
It's correct otoh, that you shouldn't be too lax with files when you
think you "secured" them somewhere in the path...=20
But if you think of /proc/x/fd as *hard* links to the files, then the
behavior would not be surprising, which might help...
(You might have this as a "real world scenario" if you have some brain
dead application which you try to secure in this way...)
Klaus
--=20
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Klaus Lichtenwalder, Dipl. Inform., http://lklaus.homelinux.org/Klaus/
PGP Key fingerprint: A5C0 F73A 2C83 96EE 766B 9C62 DB6D 1258 0E9B B6D1
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