systemd-measure can produce multiple signed policies for different
phases. However, a policy for a TPM resource that includes these signed
policies can currently be satisfied by any policy that is signed
with the same key.
It can be desirable to bind a resource's policy to one or more
specific phases. One way to do this could be to sign policies for
different phases or phase combinations with different keys. Another
approach is to limit the scope of signed policies using a policy
reference.
Using a policy reference works because:
- The reference is included along with the approved policy digest in the
digest that is signed.
- The reference argument is included in the authorization policy for a
resource via the TPM2_PolicyAuthorize assertion.
- During execution of the TPM2_PolicyAuthorize assertion, the TPM checks
that the session's current policy digest is the approved policy digest,
computes a digest from the approved policy digest and the supplied policy
reference, and checks that the resulting digest is the one that was
verified by TPM2_VerifySignature (via the returned ticket).
This adds a new --policyref argument to systemd-measure which binds all
of the signed policies to the specified policy reference. I did consider
making this more intelligent by auto-generating policy references for each
phase, but this approach provides the most flexibility for now. By making
use of the existing --append argument, a signer can produce multiple
signed policies with the same key that are bound to any individual phases
or combinations of phases.
The policy reference is a string without the NULL terminator. It is
supplied to the TPM via the TPM2B_NONCE type, which has a maximum size
equivalent to the size of the largest digest supported by the TPM. As
the signer doesn't know the capabilities of the target TPM,
systemd-measure limits the size of the policy reference to 32 bytes, to
fit within the size of a SHA256 digest.
This also includes the corresponding changes to systemd-cryptenroll and
systemd-repart (to add an equivalent --tpm2-public-key-policyref argument
so that the policy can be bound to the desired corresponding phase, and to
ensure that the policy reference is included in the LUKS2 token metadata),
and systemd-cryptsetup (to handle the policy reference stored in the LUKS2
token metadata).
This doesn't include policy reference support for credentials yet
because it requires a change to the credential headers.
The restriction requiring --empty= to be require, force, or create
when using --el-torito= is unnecessary.
context_verify_eltorito_overlap() already validates that the ISO 9660
blocks don't collide with GPT partition entries or the first usable
LBA, which is sufficient to guarantee safety regardless of the empty
mode.
This is needed for two-stage image builds where the first stage creates
the usr and verity partitions, and the second stage adds --el-torito=
to produce a bootable ISO with a UKI containing usrhash= derived from
the verity hash of the first stage. In the second stage, repart runs
with --empty=allow since the image already exists.
Co-developed-by: Claude Opus 4.6 <noreply@anthropic.com>
This only points the firmware to the ESP. The ISO9660 is empty.
The initramfs should create a loop device to change block size
and enable GPT partitions.
This was tested using OVMF on qemu, with:
`-drive if=pflash,file=OVMF_CODE.fd,readonly=on,format=raw -drive if=pflash,file=OVMF_VARS.fd,format=raw -drive if=none,id=live-disk,file=dick.iso,media=cdrom,format=raw,readonly=on -device virtio-scsi-pci,id=scsi -device scsi-cd,drive=live-disk`
And a simple definition:
```
[Partition]
Type=esp
Format=vfat
CopyFiles=/usr/lib/systemd/boot/efi/systemd-bootx64.efi:/EFI/BOOT/BOOTX64.EFI
```
Some shells will try to parse this, or expand it, causing an error. Lets
quote it so it's simpler for people.
Signed-off-by: Morten Linderud <morten@linderud.pw>
Add a --grain-size= CLI option to override the default 4 KiB partition
alignment grain. Setting --grain-size=1M matches the alignment used by
fdisk/parted and fixes misaligned partitions after small fixed-size
partitions like the 16 KiB verity-sig partition.
Also fix context_place_partitions() to re-align the start offset after
each partition, not just once per free area. Without this, a small
partition would cause all subsequent partitions in the same free area
to start at an unaligned offset.
So far repart always required specification of a device node. And if
none was specified, then we'd fine the node backing the root fs. Let's
optionally allow that the device node is explicitly not specified (i.e.
specified as "-" or ""), in which case we'll just print the size of the
minimal image given the definitions.
Add repart.d KeyFile= option with the same syntax as --key-file.
This allows a per-partition key file encryption, and not rely on a global key
applicable to all partitions.
The global --key-file overrides KeyFile config. If none of them is
defined, rely on default.
If --generate-fstab=PATH is used, there is the possibility that the
fstab file already exists, making systemd-repart fail.
This commit will add a new --append-fstab= parameter, that will read
the file and merge it with the new generated content. Using the
comments, the command can separate the automatic-generated section from
the user-provided section, allowing for the next append the replacement
only of the automatic-generated section, keeping the user one.
Signed-off-by: Alberto Planas <aplanas@suse.com>
In 2cc58b6c8a and related we established
rules on naming certs/public-keys/private-keys:
*-public-key.pem
*-private-key.pem
*-certificate.pem
Let's follow that naming in repart's man page too.
Add --join-signature=hash:sig - when a verity signature partition
has been deferred in a previous run, this allows attaching a signature
that was created offline, for example on a build system like OBS where
the private key is not available to the build process.
Can be specified multiple times, the right partition to act upon will
be selected by matching the data+verity partitions UUIDs with the
provided roothash(es)
Some ambiguity (e.g., same-named man pages in multiple volumes)
makes it impossible to fully automate this, but the following
Python snippet (run inside the man/ directory of the systemd repo)
helped to generate the sed command lines (which were subsequently
manually reviewed, run and the false positives reverted):
from pathlib import Path
import lxml
from lxml import etree as ET
man2vol: dict[str, str] = {}
man2citerefs: dict[str, list] = {}
for file in Path(".").glob("*.xml"):
tree = ET.parse(file, lxml.etree.XMLParser(recover=True))
meta = tree.find("refmeta")
if meta is not None:
title = meta.findtext("refentrytitle")
if title is not None:
vol = meta.findtext("manvolnum")
if vol is not None:
man2vol[title] = vol
citerefs = list(tree.iter("citerefentry"))
if citerefs:
man2citerefs[title] = citerefs
for man, refs in man2citerefs.items():
for ref in refs:
title = ref.findtext("refentrytitle")
if title is not None:
has = ref.findtext("manvolnum")
try:
should_have = man2vol[title]
except KeyError: # Non-systemd man page reference? Ignore.
continue
if has != should_have:
print(
f"sed -i '\\|<citerefentry><refentrytitle>{title}"
f"</refentrytitle><manvolnum>{has}</manvolnum>"
f"</citerefentry>|s|<manvolnum>{has}</manvolnum>|"
f"<manvolnum>{should_have}</manvolnum>|' {man}.xml"
)
This allows loading the X.509 certificate from an OpenSSL provider
instead of a file system path. This allows loading certficates directly
from hardware tokens instead of having to export them to a file on
disk first.
The page was written when systemd-repart was primarily intended to be used on a
running system. But nowadays it's more often used to create images, so extend
that part of the description.
While at it, fix some whitespace issues and trim some overly complicated sentences.
It turns out it's mostly PKCS11 that supports the URI format,
and other engines just take files. For example the tpm2-tss-openssl
engine just takes a sealed private key file path as the key input,
and the engine needs to be specified separately.
Add --private-key-source=file|engine:foo|provider:bar to
manually specify how to use the private key parameter.
Follow-up for 0a8264080a
These can be used along with two new settings MountPoint= and
EncryptedVolume= to write fstab and crypttab entries to the given
paths respectively in the root directory that repart is operating on.
This is useful to cover scenarios that aren't covered by the
Discoverable Partitions Spec. For example when one wants to mount
/home as a separate btrfs subvolume. Because multiple btrfs subvolumes
can be mounted from the same partition, we allow specifying MountPoint=
multiple times to add multiple entries for the same partition.
The provider API which is new requires providers, which are not
widely available and don't work very well yet, so also use a
fallback with the legacy engine API.
This adds --make-ddi=confext, --make-ddi=sysext, --make-ddi=portable, to
make it really easiy to generate DDIs of the specified class. It
it's ultimately just a fancy wrapper around some defaults and in
particular --definitions=.
This makes it very easy to generate a confext:
$ systemd-repart -C --private-key=privkey.pem --certificate=cert.crt -s mytree/ mytree.confext.raw
This specifies a directory to which CopyFiles= is considered relative.
If unset defaults to the --root=/--image= setting, or host / otherwise.
This is very similar to --root= but is much more focussed: it is really
and exclusively about CopyFiles= (and related settings such as
ExcludeFiles=) and does not affect any of the settings, i.e. it doesn't
affect CopyBlocks=, the machine ID/seed handling, or where definitions
are read from.
In fact, --root= and --copy-source= may be combined for example to
use the machine ID and similar from one tree, but the copy the files
from another.
This tries to add information about when each option was added. It goes
back to version 183.
The version info is included from a separate file to allow generating it,
which would allow more control on the formatting of the final output.
--copy-from synthesizes partition definitions from the given image
which are then applied to the repart algorithm. In its most basic
form, this allows copying an image to another device but it can
also be combined with --definitions to copy + add partitions in the
same call to repart.
--oem can be used to only install OEM partitions (usr, verity,
verity-sig, ...). OEM= is used to indicate OEM partitions. If unset,
defaults to !FactoryReset. We also add a credential repart.oem to
allow configuring --oem via a credential.
This option allows overriding the architecture that's used for the
architecture specific partition types. This is useful to allow
reusing the same repart configuration to produce the same image for
different architectures.
Fixes#22974.
The text is reworded a bit too. In particular, it's "partitions" that are not
reordered, not "partition table slots". If we were reordering things, we'd move
the partitions between slots. The slots themselves are not moveable.
Chris Coulson
Daan De Meyer
Valentin David
Morten Linderud
Nandakumar Raghavan
Daan De Meyer
Lennart Poettering
Emanuele Giuseppe Esposito
Zbigniew Jędrzejewski-Szmek
Alberto Planas
Nick Labich
Luca Boccassi
andhe
Jan Engelhardt
Yu Watanabe
Štěpán Němec
Sam Leonard
cunshunxia
Luca Boccassi
David Tardon
Abderrahim Kitouni