veritytab(5) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | SEE ALSO | COLOPHON

VERITYTAB(5)                    veritytab                   VERITYTAB(5)

NAME         top

       veritytab - Configuration for verity block devices

SYNOPSIS         top

       /etc/veritytab

DESCRIPTION         top

       The /etc/veritytab file describes verity 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 data-device hash-device roothash options

       The first four fields are mandatory, the remaining one is
       optional.

       The first field contains the name of the resulting verity volume;
       its block device is set up below /dev/mapper/.

       The second field contains a path to the underlying block data
       device, or a specification of a block device via "UUID=" followed
       by the UUID.

       The third field contains a path to the underlying block hash
       device, or a specification of a block device via "UUID=" followed
       by the UUID.

       The fourth field is the "roothash" in hexadecimal.

       The fifth field, if present, is a comma-delimited list of
       options. The following options are recognized:

       ignore-corruption, restart-on-corruption, panic-on-corruption
           Defines what to do if data integrity problem is detected
           (data corruption). Without these options kernel fails the IO
           operation with I/O error. With "--ignore-corruption" option
           the corruption is only logged. With "--restart-on-corruption"
           or "--panic-on-corruption" the kernel is restarted (panicked)
           immediately. (You have to provide way how to avoid restart
           loops.)

       ignore-zero-blocks
           Instruct kernel to not verify blocks that are expected to
           contain zeroes and always directly return zeroes instead.
           WARNING: Use this option only in very specific cases. This
           option is available since Linux kernel version 4.5.

       check-at-most-once
           Instruct kernel to verify blocks only the first time they are
           read from the data device, rather than every time. WARNING:
           It provides a reduced level of security because only offline
           tampering of the data device's content will be detected, not
           online tampering. This option is available since Linux kernel
           version 4.17.

       root-hash-signature=
           A base64 string encoding the root hash signature prefixed by
           "base64:" or a path to roothash signature file used to verify
           the root hash (in kernel). This feature requires Linux kernel
           version 5.4 or more recent.

       _netdev
           Marks this veritysetup device as requiring network. It will
           be started after the network is available, similarly to
           systemd.mount(5) units marked with _netdev. The service unit
           to set up this device will be ordered between
           remote-fs-pre.target and remote-veritysetup.target, instead
           of veritysetup-pre.target and veritysetup.target.

           Hint: if this device is used for a mount point that is
           specified in fstab(5), the _netdev option should also be used
           for the mount point. Otherwise, a dependency loop might be
           created where the mount point will be pulled in by
           local-fs.target, while the service to configure the network
           is usually only started after the local file system has been
           mounted.

       noauto
           This device will not be added to veritysetup.target. This
           means that it will not be automatically enabled on boot,
           unless something else pulls it in. In particular, if the
           device is used for a mount point, it'll be enabled
           automatically during boot, unless the mount point itself is
           also disabled with noauto.

       nofail
           This device will not be a hard dependency of
           veritysetup.target. It'll still be pulled in and started, but
           the system will not wait for the device to show up and be
           enabled, and boot will not fail if this is unsuccessful. Note
           that other units that depend on the enabled device may still
           fail. In particular, if the device is used for a mount point,
           the mount point itself also needs to have the nofail option,
           or the boot will fail if the device is not enabled
           successfully.

       x-initrd.attach
           Setup this verity integrity protected block device in the
           initramfs, similarly to systemd.mount(5) units marked with
           x-initrd.mount.

           Although it's not necessary to mark the mount entry for the
           root file system with x-initrd.mount, x-initrd.attach is
           still recommended with the verity integrity protected block
           device containing the root file system as otherwise systemd
           will attempt to detach the device during the regular system
           shutdown while it's still in use. With this option the device
           will still be detached but later after the root file system
           is unmounted.

           All other verity integrity protected block devices that
           contain file systems mounted in the initramfs should use this
           option.

       At early boot and when the system manager configuration is
       reloaded, this file is translated into native systemd units by
       systemd-veritysetup-generator(8).

EXAMPLES         top

       Example 1. /etc/veritytab example

       Set up two verity integrity protected block devices. One using
       device blocks, another using files.

           usr  PARTUUID=783e45ae-7aa3-484a-beef-a80ff9c19cbb PARTUUID=21dc1dfe-4c33-8b48-98a9-918a22eb3e37 36e3f740ad502e2c25e2a23d9c7c17bf0fdad2300b7580842d4b7ec1fb0fa263 auto
           data /etc/data /etc/hash a5ee4b42f70ae1f46a08a7c92c2e0a20672ad2f514792730f5d49d7606ab8fdf auto

SEE ALSO         top

       systemd(1), systemd-veritysetup@.service(8),
       systemd-veritysetup-generator(8), fstab(5), veritysetup(8),

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
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       This page was obtained from the project's upstream Git repository
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systemd 249                                                 VERITYTAB(5)