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From: Milan Broz <gmazyland@gmail.com>
To: gcrypt-devel@gnupg.org
Cc: dm-crypt <dm-crypt@saout.de>
Subject: [dm-crypt] Whirlpool in gcrypt <= 1.5.3 broken (if writes in chunks)?
Date: Fri, 17 Jan 2014 19:25:39 +0100	[thread overview]
Message-ID: <52D975A3.6080609@gmail.com> (raw)

Hi,

since this commit (present in 1.6.0)

"md: Fix Whirlpool flaw."
http://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commitdiff;h=0a28b2d2c9181a536fc894e24626714832619923

seems that Whirlpool hash produces different output
if data are written in parts.
(If entered as one buffer, it seems to be compatible though.)

Unfortunately, cryptsetup in its anti-forensic filter uses something like this:
  gcry_md_write(iv, iv_size)
  gcry_md_write(buf, buf_size)
  gcry_md_read ...

Change above seems to breaks all LUKS devices which used Whirlpool as hash
before and upgraded to gcrypt 1.6.0 (cryptsetup cannot open them anymore).

See for example https://bbs.archlinux.org/viewtopic.php?id=175737

Is my assumption that all whirlpool implementations before
libgcrypt 1.6.0 are broken if used this way?

(Using different crypto backend seems to support this assumption...)

Thanks,
Milan

             reply	other threads:[~2014-01-17 18:26 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-17 18:25 Milan Broz [this message]
2014-01-17 20:26 ` [dm-crypt] Whirlpool in gcrypt <= 1.5.3 broken (if writes in chunks)? Werner Koch
2014-01-17 20:58   ` Milan Broz
2014-01-19 14:13     ` Werner Koch
2014-01-19 19:49       ` Milan Broz
2014-01-20  7:56         ` Werner Koch

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