NAME¶
systemd-veritysetup-generator - Unit generator for verity
protected block devices
SYNOPSIS¶
/lib/systemd/system-generators/systemd-veritysetup-generator
DESCRIPTION¶
systemd-veritysetup-generator is a generator that translates
kernel command line options configuring verity protected block devices into
native systemd units early at boot and when configuration of the system
manager is reloaded. This will create systemd-veritysetup@.service(8)
units as necessary.
Currently, only two verity devices may be set up with this
generator, backing the root and /usr file systems of the OS.
systemd-veritysetup-generator implements
systemd.generator(7).
KERNEL COMMAND LINE¶
systemd-veritysetup-generator understands the following kernel
command line parameters:
systemd.verity=, rd.systemd.verity=
Takes a boolean argument. Defaults to "yes". If
"no", disables the generator entirely. rd.systemd.verity= is
honored only by the initrd while systemd.verity= is honored by both the
host system and the initrd.
roothash=
Takes a root hash value for the root file system. Expects
a hash value formatted in hexadecimal characters of the appropriate length
(i.e. most likely 256 bit/64 characters, or longer). If not specified via
systemd.verity_root_data= and systemd.verity_root_hash=, the
hash and data devices to use are automatically derived from the specified hash
value. Specifically, the data partition device is looked for under a GPT
partition UUID derived from the first 128bit of the root hash, the hash
partition device is looked for under a GPT partition UUID derived from the
last 128bit of the root hash. Hence it is usually sufficient to specify the
root hash to boot from a verity protected root file system, as device paths
are automatically determined from it — as long as the partition table
is properly set up.
systemd.verity_root_data=,
systemd.verity_root_hash=
These two settings take block device paths as arguments
and may be used to explicitly configure the data partition and hash partition
to use for setting up the verity protection for the root file system. If not
specified, these paths are automatically derived from the roothash=
argument (see above).
systemd.verity_root_options=
Takes a comma-separated list of dm-verity options.
Expects the following options ignore-corruption,
restart-on-corruption, ignore-zero-blocks,
check-at-most-once, panic-on-corruption and
root-hash-signature=PATH|base64:HEX.
See veritysetup(8) for more details.
usrhash=, systemd.verity_usr_data=,
systemd.verity_usr_hash=, systemd.verity_usr_options=
Equivalent to their counterparts for the root file system
as described above, but apply to the /usr/ file system instead.
