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Bug#406552: marked as done (arm: LUKS fails under load)

Your message dated Sun, 30 Sep 2007 10:07:10 +0200
with message-id <20070930080710.GR14630@deprecation.cyrius.com>
and subject line Bug#406552: arm: LUKS fails under load
has caused the attached Bug report to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what I am
talking about this indicates a serious mail system misconfiguration
somewhere.  Please contact me immediately.)

Debian bug tracking system administrator
(administrator, Debian Bugs database)
--- Begin Message --- 
Package: linux-image-2.6.18-3-ixp4xx
Version: 2.6.18-8
Severity: critical
Justification: causes serious data loss


This is on an NSLU2, I wanted to use it to access some disks that I
had used previously on another system that had encrypted partitons.
However, when I tried cryptsetup luksOpen, I got a automatic header
conversion from 0.99 to 0.991 triggered message, and then an infinite
loop. Trying the same partition on the other system, now I get the
same thing - its header is corrupted. Luckily, I'm paranoid and had a
backup of the LUKS header! If I didn't have this, the whole
partition's data would probably be lost.

Here's the result of some tests - and its stranger than you think...

Used cryptsetup luksFormat on another system to set up a partition..

LKG8A754B:~# uname -a
Linux LKG8A754B 2.6.18-3-ixp4xx #1 Mon Dec 11 17:20:00 UTC 2006 armv5tel GNU/Linux

!!! ... after some experiments corrupting it... now I restore it again
and decide to strace things... !!!

LKG8A754B:~# dd < sde4-luks-header-backup  > /dev/sde4
150+0 records in
150+0 records out
76800 bytes (77 kB) copied, 0.0148216 seconds, 5.2 MB/s
LKG8A754B:~# strace 2>trace cryptsetup luksOpen /dev/sde4 sde4
Enter LUKS passphrase: 
key slot 0 unlocked.

!!! Hey, that just worked !!!

LKG8A754B:~# ls -l /dev/mapper/sde4
brw-rw---- 1 root disk 254, 0 Dec 17 02:00 /dev/mapper/sde4
LKG8A754B:~# cmp -l /dev/sde4 sde4-luks-header-backup 
cmp: EOF on sde4-luks-header-backup

!!! But: !!!

LKG8A754B:~# cryptsetup remove sde4
!!! no strace !!!
LKG8A754B:~# cryptsetup luksOpen /dev/sde4 sde4
Enter LUKS passphrase: 
automatic header conversion from 0.99 to 0.991 triggered
<ctrl-c>
LKG8A754B:~# cmp -l /dev/sde4 sde4-luks-header-backup        
  168   0  12
  513 114   0
  514 125   0
  515 113   0
  516 123   0
  517 272   0
  518 276   0
  520   1   0
  521 141   0
  522 145   0
  523 163   0
  539   0   3
  540   0  10
  543   0  17
  544   0 240
  553 143   0
  554 142   0
  555 143   0
  556  55   0
  557 145   0
  558 163   0
  559 163   0
  560 151   0
  561 166   0
  562  72   0
  563 163   0
  564 150   0
  565 141   0
  566  62   0
  567  65   0
  568  66   0
  585 163   0
  586 150   0
  587 141   3
  588  61 210
  591   0  17
  592   0 240
cmp: EOF on sde4-luks-header-backup
LKG8A754B:~# 

!!!

Its done something like overwrite the second sector of the header with
the first one. I had a look at the cryptsetup code, and the conversion
message is triggered by it finding the wrong state code for the
passphrase slot - so the data has been overwritten by the time its got
there.

This is reliable - it always seems to corrupt it without strace,
always works with!???

Err....


-- System Information:
Debian Release: 4.0
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing')
Architecture: arm (armv5tel)
Shell:  /bin/sh linked to /bin/dash
Kernel: Linux 2.6.18-3-ixp4xx
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)

Versions of packages linux-image-2.6.18-3-ixp4xx depends on:
ii  coreutils                     5.97-5     The GNU core utilities
ii  debconf [debconf-2.0]         1.5.8      Debian configuration management sy
ii  initramfs-tools [linux-initra 0.85c      tools for generating an initramfs
ii  module-init-tools             3.3-pre3-1 tools for managing Linux kernel mo

linux-image-2.6.18-3-ixp4xx recommends no packages.

-- debconf information:
  linux-image-2.6.18-3-ixp4xx/preinst/failed-to-move-modules-2.6.18-3-ixp4xx:
  linux-image-2.6.18-3-ixp4xx/preinst/overwriting-modules-2.6.18-3-ixp4xx: true
  shared/kernel-image/really-run-bootloader: true
  linux-image-2.6.18-3-ixp4xx/postinst/kimage-is-a-directory:
  linux-image-2.6.18-3-ixp4xx/preinst/lilo-has-ramdisk:
  linux-image-2.6.18-3-ixp4xx/preinst/lilo-initrd-2.6.18-3-ixp4xx: true
  linux-image-2.6.18-3-ixp4xx/preinst/elilo-initrd-2.6.18-3-ixp4xx: true
  linux-image-2.6.18-3-ixp4xx/preinst/initrd-2.6.18-3-ixp4xx:
  linux-image-2.6.18-3-ixp4xx/preinst/bootloader-initrd-2.6.18-3-ixp4xx: true
  linux-image-2.6.18-3-ixp4xx/postinst/old-initrd-link-2.6.18-3-ixp4xx: true
  linux-image-2.6.18-3-ixp4xx/preinst/abort-install-2.6.18-3-ixp4xx:
  linux-image-2.6.18-3-ixp4xx/postinst/old-system-map-link-2.6.18-3-ixp4xx: true
  linux-image-2.6.18-3-ixp4xx/postinst/old-dir-initrd-link-2.6.18-3-ixp4xx: true
* linux-image-2.6.18-3-ixp4xx/preinst/already-running-this-2.6.18-3-ixp4xx:
  linux-image-2.6.18-3-ixp4xx/postinst/bootloader-error-2.6.18-3-ixp4xx:
  linux-image-2.6.18-3-ixp4xx/postinst/depmod-error-2.6.18-3-ixp4xx: false
  linux-image-2.6.18-3-ixp4xx/prerm/would-invalidate-boot-loader-2.6.18-3-ixp4xx: true
  linux-image-2.6.18-3-ixp4xx/prerm/removing-running-kernel-2.6.18-3-ixp4xx: true
  linux-image-2.6.18-3-ixp4xx/postinst/bootloader-test-error-2.6.18-3-ixp4xx:
  linux-image-2.6.18-3-ixp4xx/preinst/abort-overwrite-2.6.18-3-ixp4xx:
  linux-image-2.6.18-3-ixp4xx/postinst/depmod-error-initrd-2.6.18-3-ixp4xx: false
  linux-image-2.6.18-3-ixp4xx/postinst/create-kimage-link-2.6.18-3-ixp4xx: true

--- End Message ---
--- Begin Message --- 
* Gordon Farquharson <gordonfarquharson@gmail.com> [2007-09-30 00:16]:
> I made a mistake when I told you that I had checked for the presence
> of this bug in 2.6.22. I was actually working with 2.6.21 at the time.
> The good news is that I have now checked with 2.6.22 (Debian SVN 9552)
> and 2.6.23-rc8, and I am unable to trigger this bug anymore. However,
> I'm not sure what fixed the problem.
> 
> Martin, is it worth trying to isolate the patch between 2.6.21 and
> 2.6.22 that fixed this problem?

I don't think it's worth the effort.

As long as it's fixed... that's good news.  Let's close the bug.
Thanks a lot, Gordon!
-- 
Martin Michlmayr
http://www.cyrius.com/

--- End Message ---
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