[dm-crypt] [ANNOUNCE] cryptsetup 1.6.0-rc1

Milan Broz gmazyland at gmail.com
Sat Dec 29 22:40:44 CET 2012

The testing release candidate cryptsetup 1.6.0-rc1 is available at


Feedback and bug reports are welcomed.

Cryptsetup 1.6.0 Release Notes (RC1)

Changes since version 1.5.1

Important changes

 * Cryptsetup and libcryptsetup is now released under GPLv2+
   (GPL version 2 or any later).
   Some internal code handling files (loopaes, verity, tcrypt
   and crypto backend wrapper) are LGPLv2+.

   Previously code was GPL version 2 only.

 * Introducing new unified command open and close.

      cryptsetup open --type plain|luks|loopaes|tcrypt <device> <name>
      (type defaults to luks)

   with backward-compatible aliases plainOpen, luksOpen, loopaesOpen,
   tcryptOpen. Basically "open --type xyz" has alias "xyzOpen".

   The "create" command (plain device create) is DEPRECATED but will
   be still supported.
   (This command is confusing because of switched arguments order.)

   The close command is generic command to remove mapping and have
   backward compatible aliases (remove, luksClose, ...) which behaves
   exactly the same.

   While all old syntax is still supported, I strongly suggest to use
   new command syntax which is common for all device types (and possible
   new formats added in future).

 * cryptsetup now support directly TCRYPT (TrueCrypt and compatible tc-play)
   on-disk format
   (Code is independent implementation not related to original project).

   Only dump (tcryptDump command) and activation (open --type tcrypt or tcryptOpen)
   of TCRYPT device are supported. No header changes are supported.

   It is intended to easily access containers shared with other operating systems
   without need to install 3rd party software. For native Linux installations LUKS
   is the preferred format.

   WARNING: TCRYPT  extension  requires kernel userspace crypto API to be available
   (kernel af_alg and algif_skcipher modules, introduced in Linux kernel 2.6.38).

   Because  TCRYPT  header  is encrypted, you have to always provide valid
   passphrase and keyfiles. Keyfiles are handled exactly the same as in original
   format (basically, first 1MB of every keyfile is mixed using CRC32 into pool).

   Cryptsetup should recognize all TCRYPT header variants ever released, except 
   legacy  cipher chains  using LRW encryption mode with 64 bits encryption block
   (namely Blowfish in LRW mode is not recognized, this is limitation of kernel
   crypto API).

   Device activation is supported only for LRW/XTS modes (again, limitation
   of kernel dmcrypt which do not implements TCRYPT extensions to CBC mode).
   (So old containers cannot be activated, but you can use libcryptsetup
   for lost password search, example of such code is included in misc directory.)

   Hidden header are supported using --tcrypt-hidden option, system encryption
   using --tcrypt-system option.

   For detailed description see man page.

     * Dump device parameters of container in file:

     # cryptsetup tcryptDump tst
       Enter passphrase: 

     TCRYPT header information for tst
     Version:        5
     Driver req.:    7
     Sector size:    512
     MK offset:      131072
     PBKDF2 hash:    sha512
     Cipher chain:   serpent-twofish-aes
     Cipher mode:    xts-plain64
     MK bits:        1536

     You can also dump master key using --dump-master-key.
     Dump does not require superuser privilege.

     * Activation of this container

     # cryptsetup tcryptOpen tst tcrypt_dev       
       Enter passphrase: 
      (Chain of dmcrypt devices is activated as /dev/mapper/tcrypt_dev.)
     * See status of active TCRYPT device

     # cryptsetup status tcrypt_dev

     /dev/mapper/tcrypt_dev is active.
     type:    TCRYPT
     cipher:  serpent-twofish-aes-xts-plain64
     keysize: 1536 bits
     device:  /dev/loop0
     loop:    /tmp/tst
     offset:  256 sectors
     size:    65024 sectors
     skipped: 256 sectors
     mode:    read/write

    * And plaintext filesystem now ready to mount

    # blkid /dev/mapper/tcrypt_dev
    /dev/mapper/tcrypt_dev: SEC_TYPE="msdos" UUID="9F33-2954" TYPE="vfat" 

 * Add (optional) support for lipwquality for new LUKS passwords.

   If password is entered through terminal (no keyfile specified)
   and cryptsetup is compiled with --enable-pwquality, default
   system pwquality settings are used to check password quality.

   You can always override this check by using new --force-password option.

   For more info about pwquality project see http://libpwquality.fedorahosted.org/

 * Proper handle interrupt signals (ctrl+c and TERM signal) in tools

   Code should now handle interrupt properly, release and explicitly wipe
   in-memory key materials on interrupt.
   (Direct users of libcryptsetup should always call crypt_free() when
   code is interrupted to wipe all resources. There is no signal handling
   in library, it is up to the tool using it.)

 * Add new benchmark command

   The "benchmark" command now tries to benchmark PBKDF2 and some block
   cipher variants. You can specify you own parameters (--cipher/--key-size
   for block ciphers, --hash for PBKDF2).

   See man page for detailed description.

   WARNING: benchmark requires kernel userspace crypto API to be available
   (kernel af_alg and algif_skcipher modules, introduced in  Linux  kernel 2.6.38).

     # cryptsetup benchmark
     # Tests are approximate using memory only (no storage IO).
     PBKDF2-sha1       111077 iterations per second
     PBKDF2-sha256      53718 iterations per second
     PBKDF2-sha512      18832 iterations per second
     PBKDF2-ripemd160   89775 iterations per second
     PBKDF2-whirlpool   23918 iterations per second
     #  Algorithm | Key | Encryption | Decryption
          aes-cbc   128b  212.0 MiB/s  428.0 MiB/s
      serpent-cbc   128b   23.1 MiB/s   66.0 MiB/s
      twofish-cbc   128b   46.1 MiB/s   50.5 MiB/s
          aes-cbc   256b  163.0 MiB/s  350.0 MiB/s
      serpent-cbc   256b   23.1 MiB/s   66.0 MiB/s
      twofish-cbc   256b   47.0 MiB/s   50.0 MiB/s
          aes-xts   256b  190.0 MiB/s  190.0 MiB/s
      serpent-xts   256b   58.4 MiB/s   58.0 MiB/s
      twofish-xts   256b   49.0 MiB/s   49.5 MiB/s
          aes-xts   512b  175.0 MiB/s  175.0 MiB/s
      serpent-xts   512b   59.0 MiB/s   58.0 MiB/s
      twofish-xts   512b   48.5 MiB/s   49.5 MiB/s

     Or you can specify cipher yourself:
     # cryptsetup benchmark --cipher cast5-cbc-essiv:sha256 -s 128
     # Tests are approximate using memory only (no storage IO).
     #  Algorithm | Key | Encryption | Decryption
        cast5-cbc   128b   32.4 MiB/s   35.0 MiB/s

     WARNING: these tests do not use dmcrypt, only crypto API.
     You have to benchmark the whole device stack and you can get completely
     different results. But is is usable for basic comparison.
     (Note for example AES-NI decryption optimization effect in example above.)


 * Do not maintain ChangeLog file anymore, see git log for detailed changes,
   e.g. here http://code.google.com/p/cryptsetup/source/list

 * Move change key into library, add crypt_keyslot_change_by_passphrase().
   This change is useful mainly in FIPS mode, where we cannot
   extract volume key directly from libcryptsetup.

 * Add verbose messages during reencryption.

 * Default LUKS PBKDF2 iteration time is now configurable.

 * Add simple cipher benchmarking API.

 * Add kernel skcipher backend.

 * Add CRC32 implementation (for TCRYPT).

 * Move PBKDF2 into crypto backend wrapper.
   This allows use it in other formats, use library implementations and
   also possible use of different KDF function in future.

 * New PBKDF2 benchmark using getrusage().


 * Avoid O_DIRECT open if underlying storage doesn't support it.

 * Fix some non-translated messages.

 * Fix regression in header backup (1.5.1) with container in file.

 * Fix blockwise read/write for end writes near end of device.
   (was not used in previous versions)

 * Ignore setpriority failure.

 * Code changes to fix/ignore problems found by Coverity static analysis, including
   - Get page size should never fail.
   - Fix time of check/use (TOCTOU test) in tools
   - Fix time of check/use in loop/wipe utils.
   - Fix time of check/use in device utils.

 * Disallow header restore if context is non-LUKS device.

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