From: Marek Otahal <markotahal@gmail.com>
To: Kyle <lists@lolwut.org>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Impossible or Possible to Securely Erase File on Btrfs?
Date: Tue, 19 Mar 2013 23:46:01 +0100 [thread overview]
Message-ID: <1510992.7BWEEWRdZp@beruska> (raw)
In-Reply-To: <514759B5.5000507@lolwut.org>
Hi,
just reading chattr manpage..
On Monday 18 March 2013 14:15:17 you wrote:
> Hi,
>
> After reading through the btrfs documentation I'm curious to know if
> it's possible to ever securely erase a file from a btrfs filesystem (or
> ZFS for that matter). On non-COW filesystems atop regular HDDs one can
> simply overwrite the file with zeros or random data using dd or some
> other tool and rest assured that the blocks which contained the
> sensitive information have been wiped. However on btrfs it would seem
> any such attempt would write the zeros/random data to a new location,
> leaving the old blocks with the sensitive data intact. Further, since
> specifying NOCOW is only possible for newly created files, there seems
> to be no way to overwrite the appropriate blocks short of deleting the
> associated file and then filling the entire free filesystem space with
> zeros/random data such that the old blocks are eventually overwritten.
> What's the verdict on this?
what would chattr +s do?
"
When a file with the `s' attribute set is deleted, its blocks are zeroed and written back to the disk. Note: please make sure to read the bugs and limitations section at the end of this document.
"
Nice spring to all of you! :)
Mark
>
> Regards,
>
> Kyle
> --
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--
Marek Otahal :o)
next prev parent reply other threads:[~2013-03-19 22:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-18 18:15 Impossible or Possible to Securely Erase File on Btrfs? Kyle
2013-03-18 18:57 ` Hugo Mills
2013-03-18 19:09 ` Chris Murphy
2013-03-18 23:00 ` Kyle
2013-03-19 4:41 ` Chris Murphy
2013-03-18 19:18 ` Chris Mason
2013-03-18 22:48 ` Gareth Pye
2013-03-19 9:19 ` David Sterba
2013-03-19 3:18 ` Chris Murphy
2013-03-19 9:06 ` David Sterba
2013-03-20 0:52 ` Chris Murphy
2013-03-19 22:46 ` Marek Otahal [this message]
2013-03-20 19:20 ` Martin Steigerwald
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