systemd-veritysetup-generator - Unit generator for integrity
protected block devices
systemd-veritysetup-generator is a generator that translates
kernel command line options configuring integrity-protected block devices
(verity) 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 a single verity device may be set up with this
generator, backing the root file system of the OS.
KERNEL COMMAND LINE¶
systemd-veritysetup-generator understands the following kernel
command line parameters:
Takes a boolean argument. Defaults to "yes". If
"no", disables the generator entirely. rd.systemd.verity= is
honored only by the initial RAM disk (initrd) while systemd.verity= is
honored by both the host system and the initrd.
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 an integrity protected root file system, as device
paths are automatically determined from it — as long as the partition
table is properly set up.
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 integrity protection for the root file system. If
not specified, these paths are automatically derived from the roothash=
argument (see above).