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Cryptsetup 2.1.0 Release Notes
==============================
Stable release with new features and bug fixes.
Cryptsetup 2.1 version uses a new on-disk LUKS2 format as the default
LUKS format and increases default LUKS2 header size.
The legacy LUKS (referenced as LUKS1) will be fully supported forever
as well as a traditional and fully backward compatible format.
When upgrading a stable distribution, please use configure option
--with-default-luks-format=LUKS1 to maintain backward compatibility.
This release also switches to OpenSSL as a default cryptographic
backend for LUKS header processing. Use --with-crypto_backend=gcrypt
configure option if you need to preserve legacy libgcrypt backend.
Please do not use LUKS2 without properly configured backup or
in production systems that need to be compatible with older systems.
Changes since version 2.0.6
~~~~~~~~~~~~~~~~~~~~~~~~~~~
* The default for cryptsetup LUKS format action is now LUKS2.
You can use LUKS1 with cryptsetup option --type luks1.
* The default size of the LUKS2 header is increased to 16 MB.
It includes metadata and the area used for binary keyslots;
it means that LUKS header backup is now 16MB in size.
Note, that used keyslot area is much smaller, but this increase
of reserved space allows implementation of later extensions
(like online reencryption).
It is fully compatible with older cryptsetup 2.0.x versions.
If you require to create LUKS2 header with the same size as
in the 2.0.x version, use --offset 8192 option for luksFormat
(units are in 512-bytes sectors; see notes below).
* Cryptsetup now doubles LUKS default key size if XTS mode is used
(XTS mode uses two internal keys). This does not apply if key size
is explicitly specified on the command line and it does not apply
for the plain mode.
This fixes a confusion with AES and 256bit key in XTS mode where
code used AES128 and not AES256 as often expected.
Also, the default keyslot encryption algorithm (if cannot be derived
from data encryption algorithm) is now available as configure
options --with-luks2-keyslot-cipher and --with-luks2-keyslot-keybits.
The default is aes-xts-plain64 with 2 * 256-bits key.
* Default cryptographic backend used for LUKS header processing is now
OpenSSL. For years, OpenSSL provided better performance for PBKDF.
NOTE: Cryptsetup/libcryptsetup supports several cryptographic
library backends. The fully supported are libgcrypt, OpenSSL and
kernel crypto API. FIPS mode extensions are maintained only for
libgcrypt and OpenSSL. Nettle and NSS are usable only for some
subset of algorithms and cannot provide full backward compatibility.
You can always switch to other backends by using a configure switch,
for libgcrypt (compatibility for older distributions) use:
--with-crypto_backend=gcrypt
* The Python bindings are no longer supported and the code was removed
from cryptsetup distribution. Please use the libblockdev project
that already covers most of the libcryptsetup functionality
including LUKS2.
* Cryptsetup now allows using --offset option also for luksFormat.
It means that the specified offset value is used for data offset.
LUKS2 header areas are automatically adjusted according to this value.
(Note units are in 512-byte sectors due to the previous definition
of this option in plain mode.)
This option can replace --align-payload with absolute alignment value.
* Cryptsetup now supports new refresh action (that is the alias for
"open --refresh").
It allows changes of parameters for an active device (like root
device mapping), for example, it can enable or disable TRIM support
on-the-fly.
It is supported for LUKS1, LUKS2, plain and loop-AES devices.
* Integritysetup now supports mode with detached data device through
new --data-device option.
Since kernel 4.18 there is a possibility to specify external data
device for dm-integrity that stores all integrity tags.
* Integritysetup now supports automatic integrity recalculation
through new --integrity-recalculate option.
Linux kernel since version 4.18 supports automatic background
recalculation of integrity tags for dm-integrity.
Other changes and fixes
~~~~~~~~~~~~~~~~~~~~~~~
* Fix for crypt_wipe call to allocate space if the header is backed
by a file. This means that if you use detached header file, it will
now have always the full size after luksFormat, even if only
a few keyslots are used.
* Fixes to offline cryptsetup-reencrypt to preserve LUKS2 keyslots
area sizes after reencryption and fixes for some other issues when
creating temporary reencryption headers.
* Added some FIPS mode workarounds. We cannot (yet) use Argon2 in
FIPS mode, libcryptsetup now fallbacks to use PBKDF2 in FIPS mode.
* Rejects conversion to LUKS1 if PBKDF2 hash algorithms
in keyslots differ.
* The hash setting on command line now applies also to LUKS2 PBKDF2
digest. In previous versions, the LUKS2 key digest used PBKDF2-SHA256
(except for converted headers).
* Allow LUKS2 keyslots area to increase if data offset allows it.
Cryptsetup can fine-tune LUKS2 metadata area sizes through
--luks2-metadata-size=BYTES and --luks2-keyslots-size=BYTES.
Please DO NOT use these low-level options until you need it for
some very specific additional feature.
Also, the code now prints these LUKS2 header area sizes in dump
command.
* For LUKS2, keyslot can use different encryption that data with
new options --keyslot-key-size=BITS and --keyslot-cipher=STRING
in all commands that create new LUKS keyslot.
Please DO NOT use these low-level options until you need it for
some very specific additional feature.
* Code now avoids data flush when reading device status through
device-mapper.
* The Nettle crypto backend and the userspace kernel crypto API
backend were enhanced to allow more available hash functions
(like SHA3 variants).
* Upstream code now does not require libgcrypt-devel
for autoconfigure, because OpenSSL is the default.
The libgcrypt does not use standard pkgconfig detection and
requires specific macro (part of libgcrypt development files)
to be always present during autoconfigure.
With other crypto backends, like OpenSSL, this makes no sense,
so this part of autoconfigure is now optional.
* Cryptsetup now understands new --debug-json option that allows
an additional dump of some JSON information. These are no longer
present in standard debug output because it could contain some
specific LUKS header parameters.
* The luksDump contains the hash algorithm used in Anti-Forensic
function.
* All debug messages are now sent through configured log callback
functions, so an application can easily use own debug messages
handling. In previous versions debug messages were printed directly
to standard output.)
Libcryptsetup API additions
~~~~~~~~~~~~~~~~~~~~~~~~~~~
These new calls are now exported, for details see libcryptsetup.h:
* crypt_init_data_device
* crypt_get_metadata_device_name
functions to init devices with separate metadata and data device
before a format function is called.
* crypt_set_data_offset
sets the data offset for LUKS to the specified value
in 512-byte sectors.
It should replace alignment calculation in LUKS param structures.
* crypt_get_metadata_size
* crypt_set_metadata_size
allows one to set/get area sizes in LUKS header
(according to specification).
* crypt_get_default_type
get default compiled-in LUKS type (version).
* crypt_get_pbkdf_type_params
allows one to get compiled-in PBKDF parameters.
* crypt_keyslot_set_encryption
* crypt_keyslot_get_encryption
allows one to set/get per-keyslot encryption algorithm for LUKS2.
* crypt_keyslot_get_pbkdf
allows one to get PBKDF parameters per-keyslot.
and these new defines:
* CRYPT_LOG_DEBUG_JSON (message type for JSON debug)
* CRYPT_DEBUG_JSON (log level for JSON debug)
* CRYPT_ACTIVATE_RECALCULATE (dm-integrity recalculate flag)
* CRYPT_ACTIVATE_REFRESH (new open with refresh flag)
All existing API calls should remain backward compatible.
Unfinished things & TODO for next releases
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Optional authenticated encryption is still an experimental feature
and can have performance problems for high-speed devices and device
with larger IO blocks (like RAID).
* Authenticated encryption does not use encryption for a dm-integrity
journal. While it does not influence data confidentiality or
integrity protection, an attacker can get some more information
from data journal or cause that system will corrupt sectors after
journal replay. (That corruption will be detected though.)
* The LUKS2 metadata area increase is mainly needed for the new online
reencryption as the major feature for the next release.
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