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  11. Mar 28, 2017
    • Heinz Mauelshagen's avatar
      dm raid: add raid4/5/6 journal write-back support via journal_mode option · 6e53636f
      Heinz Mauelshagen authored 
      Commit 63c32ed4

 ("dm raid: add raid4/5/6 journaling support") added
journal support to close the raid4/5/6 "write hole" -- in terms of
writethrough caching.

Introduce a "journal_mode" feature and use the new
r5c_journal_mode_set() API to add support for switching the journal
device's cache mode between write-through (the current default) and
write-back.

NOTE: If the journal device is not layered on resilent storage and it
fails, write-through mode will cause the "write hole" to reoccur.  But
if the journal fails while in write-back mode it will cause data loss
for any dirty cache entries unless resilent storage is used for the
journal.

Signed-off-by: default avatarHeinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      6e53636f
  13. Mar 27, 2017
  15. Mar 25, 2017
    • Mikulas Patocka's avatar
      dm crypt: use shifts instead of sector_div · ff3af92b
      Mikulas Patocka authored 
      

sector_div is very slow, so we introduce a variable sector_shift and
use shift instead of sector_div.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      ff3af92b
    • Mikulas Patocka's avatar
      dm integrity: add recovery mode · c2bcb2b7
      Mikulas Patocka authored 
      

In recovery mode, we don't:
- replay the journal
- check checksums
- allow writes to the device

This mode can be used as a last resort for data recovery.  The
motivation for recovery mode is that when there is a single error in the
journal, the user should not lose access to the whole device.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      c2bcb2b7
    • Mike Snitzer's avatar
      dm integrity: factor out create_journal() from dm_integrity_ctr() · 1aa0efd4
      Mike Snitzer authored 
      

Preparation for next commit that makes call to create_journal()
optional.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      1aa0efd4
    • Milan Broz's avatar
      dm crypt: optionally support larger encryption sector size · 8f0009a2
      Milan Broz authored 
      

Add  optional "sector_size"  parameter that specifies encryption sector
size (atomic unit of block device encryption).

Parameter can be in range 512 - 4096 bytes and must be power of two.
For compatibility reasons, the maximal IO must fit into the page limit,
so the limit is set to the minimal page size possible (4096 bytes).

NOTE: this device cannot yet be handled by cryptsetup if this parameter
is set.

IV for the sector is calculated from the 512 bytes sector offset unless
the iv_large_sectors option is used.

Test script using dmsetup:

  DEV="/dev/sdb"
  DEV_SIZE=$(blockdev --getsz $DEV)
  KEY="9c1185a5c5e9fc54612808977ee8f548b2258d31ddadef707ba62c166051b9e3cd0294c27515f2bccee924e8823ca6e124b8fc3167ed478bca702babe4e130ac"
  BLOCK_SIZE=4096

  # dmsetup create test_crypt --table "0 $DEV_SIZE crypt aes-xts-plain64 $KEY 0 $DEV 0 1 sector_size:$BLOCK_SIZE"
  # dmsetup table --showkeys test_crypt

Signed-off-by: default avatarMilan Broz <gmazyland@gmail.com>
...
      8f0009a2
    • Milan Broz's avatar
      dm crypt: introduce new format of cipher with "capi:" prefix · 33d2f09f
      Milan Broz authored 
      

For the new authenticated encryption we have to support generic composed
modes (combination of encryption algorithm and authenticator) because
this is how the kernel crypto API accesses such algorithms.

To simplify the interface, we accept an algorithm directly in crypto API
format.  The new format is recognised by the "capi:" prefix.  The
dmcrypt internal IV specification is the same as for the old format.

The crypto API cipher specifications format is:
     capi:cipher_api_spec-ivmode[:ivopts]
Examples:
     capi:cbc(aes)-essiv:sha256 (equivalent to old aes-cbc-essiv:sha256)
     capi:xts(aes)-plain64      (equivalent to old aes-xts-plain64)
Examples of authenticated modes:
     capi:gcm(aes)-random
     capi:authenc(hmac(sha256),xts(aes))-random
     capi:rfc7539(chacha20,poly1305)-random

Authenticated modes can only be configured using the new cipher format.
Note that this format allows user to specify arbitrary combinations that
can be insecure. (Policy decision is done in cryptsetup userspace.)

Authenticated encryption algorithms can be of two types, either native
modes (like GCM) that performs both encryption and authentication
internally, or composed modes where user can compose AEAD with separate
specification of encryption algorithm and authenticator.

For composed mode with HMAC (length-preserving encryption mode like an
XTS and HMAC as an authenticator) we have to calculate HMAC digest size
(the separate authentication key is the same size as the HMAC digest).
Introduce crypt_ctr_auth_cipher() to parse the crypto API string to get
HMAC algorithm and retrieve digest size from it.

Also, for HMAC composed mode we need to parse the crypto API string to
get the cipher mode nested in the specification.  For native AEAD mode
(like GCM), we can use crypto_tfm_alg_name() API to get the cipher
specification.

Because the HMAC composed mode is not processed the same as the native
AEAD mode, the CRYPT_MODE_INTEGRITY_HMAC flag is no longer needed and
"hmac" specification for the table integrity argument is removed.

Signed-off-by: default avatarMilan Broz <gmazyland@gmail.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      33d2f09f
    • Milan Broz's avatar
      dm crypt: factor IV constructor out to separate function · e889f97a
      Milan Broz authored 
      

No functional change.

Signed-off-by: default avatarMilan Broz <gmazyland@gmail.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      e889f97a