Adds support for LUKS2 decryption of devices with a
header put in the head of data device. During the initialization
header is exported to a file and first data segment
is moved to head of data device in place of original header.
The feature introduces several new resilience modes (combination
of existing modes datashift and "checksum" or "journal").
Where datashift resilience mode is applied for data moved towards
the first segment and first segment is decrypted in-place.
The mode is not backward compatible with prior LUKS2 reencryption
and therefor interrupted operation in progress can not be resumed
using older cryptsetup releases.
Fixes: #669.
Upper layers always expected 0 on error.
Due to this bug this function could cause
sector_size overflow when segment definition
did not contain 'sector_size' field ('linear').
If some kdf are not available, we incuidentally returned EINVAL
error code instead od EPERM.
This caused that error message is not correctly printed and also
retry count is not applied.
Fixes: #745.
Refresh (and therefore suspend hotzone) reencryption dm
segments in-before actual hotzone reencryption takes place.
This commit shortens time window during which hotzone is
suspended. Also it avoids eventual deadlock if reencryption process
triggers page miss during storage wrapper reinitialization and required
data is stored in (previously) suspended hotzone (corner case).
Checksum hash parameter obtained via API call can not be used directly.
It gets lost during subsequent call to crypt_reencrypt_init_by_* API
when library reloads crypt context.
There are some historic incompatibilities that are ignored
for LUKS1 but do not work for LUKS2.
Check the cipher before conversion through crypto backend.
Also it switches LUKS2_check_cipher to use userspace backend only
(this should be ok for the reencryption code that uses it too).
Fixes: #641
Due to commit 0113ac2d88
we recalculate reencryption digest whenever LUKS2 reencryption
keyslot gets updated. Until now we perform reencryption digest
refresh every time we call LUKS2_keyslot_reencrypt_update even
when no metadata was updated.
This improves on it and should speed up reencryption resume
process.
