x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
INTEGRITYTAB(5) integritytab INTEGRITYTAB(5)
NAME
integritytab - Configuration for integrity block devices
SYNOPSIS
/etc/integritytab
DESCRIPTION
The /etc/integritytab file describes integrity protected block devices
that are set up during system boot.
Empty lines and lines starting with the "#" character are ignored. Each
of the remaining lines describes one verity integrity protected block
device. Fields are delimited by white space.
Each line is in the form
volume-name block-device
[keyfile|-] [options|-]
The first two fields are mandatory, the remaining two are optional and
only required if user specified non-default options during integrity
format.
The first field contains the name of the resulting integrity volume;
its block device is set up below /dev/mapper/.
The second field contains a path to the underlying block device, or a
specification of a block device via "UUID=" followed by the UUID,
"PARTUUID=" followed by the partition UUID, "LABEL=" followed by the
label, "PARTLABEL=" followed by the partition label.
The third field if present contains an absolute filename path to a key
file or a "-" to specify none. When the filename is present, the
"integrity-algorithm" defaults to "hmac-sha256" with the key length
derived from the number of bytes in the key file. At this time the only
supported integrity algorithm when using key file is hmac-sha256. The
maximum size of the key file is 4096 bytes.
The fourth field, if present, is a comma-delimited list of options or a
"-" to specify none. The following options are recognized:
allow-discards
Allow the use of discard (TRIM) requests for the device. This
option is available since the Linux kernel version 5.7.
mode=(journal|bitmap|direct)
Enable journaled, bitmapped or direct (passthrough) mode. Journaled
mode is the default when this option is not specified. It provides
safety against crashes, but can be slow because all data has to be
written twice. Bitmap mode is more efficient since it requires only
a single write, but it is less reliable because if data corruption
happens when the machine crashes, it may not be detected. Direct
mode disables the journal and the bitmap. Corresponds to the
"direct writes" mode documented in the dm-integrity
documentation[1]. Note that without a journal, if there is a crash,
it is possible that the integrity tags and data will not match. If
used, the journal-* options below will have no effect if passed.
journal-watermark=[0..100]%
Journal watermark in percent. When the journal percentage exceeds
this watermark, the journal flush will be started. Setting a value
of "0%" uses default value.
journal-commit-time=[0..N]
Commit time in milliseconds. When this time passes (and no explicit
flush operation was issued), the journal is written. Setting a
value of zero uses default value.
data-device=/dev/disk/by-...
Specify a separate block device that contains existing data. The
second field specified in the integritytab for block device then
will contain calculated integrity tags and journal for data-device,
but not the end user data.
integrity-algorithm=[crc32c|crc32|sha1|sha256|hmac-sha256]
The algorithm used for integrity checking. The default is crc32c.
Must match option used during format.
At early boot and when the system manager configuration is reloaded,
this file is translated into native systemd units by systemd-
integritysetup-generator(8).
EXAMPLES
Example 1. /etc/integritytab
Set up two integrity protected block devices.
home PARTUUID=4973d0b8-1b15-c449-96ec-94bab7f6a7b8 - journal-commit-time=10,allow-discards,journal-watermark=55%
data PARTUUID=5d4b1808-be76-774d-88af-03c4c3a41761 - allow-discards
Example 2. /etc/integritytab
Set up 1 integrity protected block device using defaults
home PARTUUID=4973d0b8-1b15-c449-96ec-94bab7f6a7b8
Example 3. /etc/integritytab
Set up 1 integrity device using existing data block device which
contains user data
home PARTUUID=4973d0b8-1b15-c449-96ec-94bab7f6a7b8 - data-device=/dev/disk/by-uuid/9276d9c0-d4e3-4297-b4ff-3307cd0d092f
Example 4. /etc/integritytab
Set up 1 integrity device using a HMAC key file using defaults
home PARTUUID=4973d0b8-1b15-c449-96ec-94bab7f6a7b8 /etc/hmac.key
SEE ALSO
systemd(1), systemd-integritysetup@.service(8), systemd-integritysetup-
generator(8), integritysetup(8),
NOTES
1. the dm-integrity documentation
https://docs.kernel.org/admin-guide/device-mapper/dm-integrity.html
systemd 254 INTEGRITYTAB(5)
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