[Bug 573858] Re: Possible data loss caused by cryptdisks_start

[zatoichi0]

*** This bug is a duplicate of bug 474258 ***
    https://bugs.launchpad.net/bugs/474258

** This bug has been marked a duplicate of bug 584067
   setting up swap encryption from alternate CD uses unstable device nodes

** This bug is no longer a duplicate of bug 584067
   setting up swap encryption from alternate CD uses unstable device nodes
** This bug has been marked a duplicate of bug 474258
   Extremely dangerous! cryptswap killed my partition

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Title:
  Possible data loss caused by cryptdisks_start

Status in “cryptsetup” package in Ubuntu:
  New

Bug description:
  Binary package hint: cryptsetup

  cryptdisks_start can lead to a data loss:

  By upgrading from karmic to lucid device names for harddisks changed.
  (SATA is now assigned second, IDE first - at least on my system.)
  After this the original swap partition name (/dev/sda1, now /dev/sdb1)
  pointed to a windows ntfs filesystem (now /dev/sda1, /dev/sdb1
  before).

  swapon checks for a swap signature before using a partition, however
  the device mapper, which the cryptsetup uses for providing encrypted
  devices, does not check anything, since it simply expects data, which
  is not interpreted in any way (by the device mapper itself). Resulting
  from this the device mapper happely provides a data partition for
  cryptsetup. (In my case it made windows unbootable, but there had been
  lots of trouble, if my swap usage was higher!)

  cryptdisks_start should somehow make sure that such things don't
  happen. UUIDs can be used without any further checking, but in case of
  pure device names, it should at least make sure, that the partition ID
  is 82 (Linux Swap / Solaris) or not accept pure device names at all
  for swap.

  Workaround:
  Use UUIDs in /etc/crypttab, this makes sure no wrong partition is used for swap.

  In order to check, whether your system is affected use 'free' to
  check, whether swap size is correct. I myself was able to get windows
  back to boot, but in other cased, the ntfs filesystem may be damaged
  much more.

  References - I think these errors may be caused by above bug:
  http://www.supergrubdisk.org/forum/index.php?topic=467
  https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/571893

  I myself thought, that it was a grub bug first, but I think cryptsetup
  (cryptdisk_start) is the real problem.

  ...

  Just checked the scripts a bit and it seems, that checking is really
  done. /sbin/blkid is called by the scripts, but it does return nothing
  for a swap partition (with an empty label in my case). Maybe this is a
  bug in /sbin/blkid from util-linux, but I'm not sure, since I don't
  completly understand the scripts in /lib/cryptsetup/*.

  ProblemType: Bug
  DistroRelease: Ubuntu 10.04
  Package: cryptsetup 2:1.1.0~rc2-1ubuntu13
  ProcVersionSignature: Ubuntu 2.6.32-21.32-generic 2.6.32.11+drm33.2
  Uname: Linux 2.6.32-21-generic i686
  NonfreeKernelModules: fglrx
  Architecture: i386
  Date: Sun May  2 19:26:37 2010
  ProcEnviron:
   PATH=(custom, no user)
   LANG=de_DE.UTF-8
   SHELL=/bin/bash
  SourcePackage: cryptsetup
  crypttab:
   # <target name>	<source device>		<key file>	<options>
   cryptswap1 UUID=e3d8e700-f75a-4f54-ae49-fd3a770c39a7 /dev/urandom swap,cipher=aes-cbc-essiv:sha256

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