Gentoo Archives: gentoo-security

From: Spider <spider@g.o>
To: gentoo-security@l.g.o
Subject: Re: [gentoo-security] Secure deletion of files...
Date: Thu, 06 May 2004 10:01:05
Message-Id: 20040506120014.3d046419.spider@gentoo.org
In Reply to: Re: [gentoo-security] Secure deletion of files... by Ryan Voots
1 begin quote
2 On Wed, 5 May 2004 20:04:44 -0400
3 Ryan Voots <simcop2387@×××××.com> wrote:
4
5 > On Tue, 4 May 2004 09:54:36 +0200
6 > "Marc Ballarin" <Ballarin.Marc@×××.de> wrote:
7 > > shred is not reliable on modern filesystems. Clever block allocation
8 > > algorithms, journalling and on-disk write-caches make secure
9 > > deletion from
10 > > userspace unreliable (shred's man page lists even more examples).
11 >
12 > i've actually thought about that problem and was wondering, since the
13 > clever file systems and such would probably not want to move the
14 > blocks around on every write, why couldn't you zero out the file
15 > backwards (i understand this could end up a buffering issue but i
16 > think that can be worked around) after that you just delete it like
17 > normal?
18
19 one word:
20 blockreallocation
21 (well.. *cough* ;)
22
23 modern harddrives are actually larger than specified, and use something
24 around 1Gb (perhaps more?) to shuffle around "bad blocks" and damaged
25 sectors and do other black majjik.
26
27 you cant even reach theese from software.
28
29 put simply: You can't delete things from your harddrive. You can only
30 reuse the space and hope for the best.
31
32 //Spider
33
34
35 --
36 begin .signature
37 Tortured users / Laughing in pain
38 See Microsoft KB Article Q265230 for more information.
39 end