integritysetup(8) - phpMan

INTEGRITYSETUP(8) Maintenance Commands INTEGRITYSETUP(8)

NAME
integritysetup - manage dm-integrity (block level integrity) volumes

SYNOPSIS
integritysetup <options> <action> <action args>

DESCRIPTION
Integritysetup is used to configure dm-integrity managed device-mapper mappings.

Device-mapper integrity target provides read-write transparent integrity checking of block
devices. The dm-integrity target emulates additional data integrity field per-sector. You
can use this additional field directly with integritysetup utility, or indirectly (for au-
thenticated encryption) through cryptsetup.

Integritysetup supports these operations:

format <device>

Formats <device> (calculates space and dm-integrity superblock and wipes the de-
vice).

<options> can be [--data-device, --batch-mode, --no-wipe, --journal-size, --inter-
leave-sectors, --tag-size, --integrity, --integrity-key-size, --integrity-key-file,
--sector-size, --progress-frequency]

open <device> <name>
create <name> <device> (OBSOLETE syntax)

Open a mapping with <name> backed by device <device>.

<options> can be [--data-device, --batch-mode, --journal-watermark, --journal-com-
mit-time, --buffer-sectors, --integrity, --integrity-key-size, --integ-
rity-key-file, --integrity-no-journal, --integrity-recalculate, --integrity-recal-
culate-reset,--integrity-recovery-mode, --allow-discards]

close <name>

Removes existing mapping <name>.

For backward compatibility, there is remove command alias for the close command.

<options> can be [--deferred] or [--cancel-deferred]

status <name>

Reports status for the active integrity mapping <name>.

dump <device>

Reports parameters from on-disk stored superblock.

OPTIONS
--verbose, -v
Print more information on command execution.

--debug
Run in debug mode with full diagnostic logs. Debug output lines are always prefixed
by '#'.

--version
Show the program version.

--batch-mode
Do not ask for confirmation.

--progress-frequency <seconds>
Print separate line every <seconds> with wipe progress.

--no-wipe
Do not wipe the device after format. A device that is not initially wiped will con-
tain invalid checksums.

--journal-size, -j BYTES
Size of the journal.

--interleave-sectors SECTORS
The number of interleaved sectors.

--integrity-recalculate
Automatically recalculate integrity tags in kernel on activation. The device can
be used during automatic integrity recalculation but becomes fully integrity pro-
tected only after the background operation is finished. This option is available
since the Linux kernel version 4.19.

--integrity-recalculate-reset
Restart recalculation from the beginning of the device. It can be used to change
the integrity checksum function. Note it does not change the tag length. This op-
tion is available since the Linux kernel version 5.13.

--journal-watermark PERCENT
Journal watermark in percents. When the size of the journal exceeds this watermark,
the journal flush will be started.

--journal-commit-time MS
Commit time in milliseconds. When this time passes (and no explicit flush operation
was issued), the journal is written.

--tag-size, -t BYTES
Size of the integrity tag per-sector (here the integrity function will store au-
thentication tag).

NOTE: The size can be smaller that output size of the hash function, in that case
only part of the hash will be stored.

--data-device
Specify a separate data device that contains existing data. The <device> then will
contain calculated integrity tags and journal for this data device.

--sector-size, -s BYTES
Sector size (power of two: 512, 1024, 2048, 4096).

--buffer-sectors SECTORS
The number of sectors in one buffer.

The tag area is accessed using buffers, the large buffer size means that the I/O
size will be larger, but there could be less I/Os issued.

--integrity, -I ALGORITHM
Use internal integrity calculation (standalone mode). The integrity algorithm can
be CRC (crc32c/crc32) or hash function (sha1, sha256).

For HMAC (hmac-sha256) you have also to specify an integrity key and its size.

--integrity-key-size BYTES
The size of the data integrity key. Maximum is 4096 bytes.

--integrity-key-file FILE
The file with the integrity key.

--integrity-no-journal, -D
Disable journal for integrity device.

--integrity-bitmap-mode. -B
Use alternate bitmap mode (available since Linux kernel 5.2) where dm-integrity
uses bitmap instead of a journal. If a bit in the bitmap is 1, the corresponding
region's data and integrity tags are not synchronized - if the machine crashes, the
unsynchronized regions will be recalculated. The bitmap mode is faster than the
journal mode, because we don't have to write the data twice, but it is also less
reliable, because if data corruption happens when the machine crashes, it may not
be detected.

--bitmap-sectors-per-bit SECTORS
Number of 512-byte sectors per bitmap bit, the value must be power of two.

--bitmap-flush-time MS
Bitmap flush time in milliseconds.

WARNING:
In case of a crash, it is possible that the data and integrity tag doesn't match if
the journal is disabled.

--integrity-recovery-mode. -R
Recovery mode (no journal, no tag checking).

NOTE: The following options are intended for testing purposes only.
Using journal encryption does not make sense without encryption the data, these op-
tions are internally used in authenticated disk encryption with cryptsetup(8).

--journal-integrity ALGORITHM
Integrity algorithm for journal area. See --integrity option for detailed specifi-
cation.

--journal-integrity-key-size BYTES
The size of the journal integrity key. Maximum is 4096 bytes.

--journal-integrity-key-file FILE
The file with the integrity key.

--journal-crypt ALGORITHM
Encryption algorithm for journal data area. You can use a block cipher here such
as cbc-aes or a stream cipher, for example, chacha20 or ctr-aes.

--journal-crypt-key-size BYTES
The size of the journal encryption key. Maximum is 4096 bytes.

--journal-crypt-key-file FILE
The file with the journal encryption key.

--allow-discards
Allow the use of discard (TRIM) requests for the device. This option is available
since the Linux kernel version 5.7.

--deferred
Defers device removal in close command until the last user closes it.

--cancel-deferred
Removes a previously configured deferred device removal in close command.

The dm-integrity target is available since Linux kernel version 4.12.

NOTE: Format and activation of an integrity device always require superuser privilege be-
cause the superblock is calculated and handled in dm-integrity kernel target.

LEGACY COMPATIBILITY OPTIONS
WARNING:
Do not use these options until you need compatibility with specific old kernel.

--integrity-legacy-padding
Use inefficient legacy padding.

--integrity-legacy-hmac
Use old flawed HMAC calclation (also does not protect superblock).

--integrity-legacy-recalculate
Allow insecure recalculating of volumes with HMAC keys (recalcualtion offset in su-
perblock is not protected).

RETURN CODES
Integritysetup returns 0 on success and a non-zero value on error.

Error codes are:
1 wrong parameters
2 no permission
3 out of memory
4 wrong device specified
5 device already exists, or device is busy.

EXAMPLES
Format the device with default standalone mode (CRC32C):

integritysetup format <device>

Open the device with default parameters:

integritysetup open <device> test

Format the device in standalone mode for use with HMAC(SHA256):

integritysetup format <device> --tag-size 32 --integrity hmac-sha256 --integrity-key-file
<keyfile> --integrity-key-size <key_bytes>

Open (activate) the device with HMAC(SHA256) and HMAC key in file:

integritysetup open <device> test --integrity hmac-sha256 --integrity-key-file <keyfile>
--integrity-key-size <key_bytes>

Dump dm-integrity superblock information:

integritysetup dump <device>

REPORTING BUGS
Report bugs, including ones in the documentation, on the cryptsetup mailing list at <dm-
crypt AT saout.de> or in the 'Issues' section on LUKS website. Please attach the output of
the failed command with the --debug option added.

AUTHORS
The integritysetup tool is written by Milan Broz <gmazyland AT gmail.com> and is part of the
cryptsetup project.

This is free software; see the source for copying conditions. There is NO warranty; not
even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO
The project website at https://gitlab.com/cryptsetup/cryptsetup

The integrity on-disk format specification available at https://gitlab.com/crypt-
setup/cryptsetup/wikis/DMIntegrity

integritysetup January 2021 INTEGRITYSETUP(8)

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