This updates systemd-tpm2-setup to create and persist an endorsement
key if there isn't one already. For each supported EK template profile,
it will read the EK certificate from its NV index if there is one.
When there is an EK certificate present, a primary key is created using
the corresponding template. If the resulting EKpub matches the public
key in the certificate, the created EK is persisted and the process is
complete.
The low-range templates and the high-range RSA 2048/3072 and ECC NIST
P256/P384 storage templates are supported, as detailed in section
5.3 of the "TCG EK Credential Profile For TPM Family 2.0" spec v2.7.
High-range templates are preferred because these permit EK usage without
requiring knowledge of the authorization value for the endorsement
hierarchy, meaning that, like with the SRK, it is possible to restrict
the usage of the endorsement hierarchy whilst still permitting use of
the persistent EK.
The EK is always persisted at handle 0x81010001. This handle is
reserved in Table 2 of the "TCG TPM v2.0 Provisioning Guidance" spec
v1.0r1.0, although this is only a recommendation. This
handle is within the block of handles reserved for endorsement
primary keys in the "Registry of Reserved TPM 2.0 Handles and
Localities" spec v1.2r1.00. Section 2.3.2 of this specification also
makes a suggestion that there should be a relationship between the EK
certificate NV index and a corresponding persistent EK handle by
using handles at the same offsets within their respective ranges.
However, this contradicts the provisioning guidance spec which reserves
0x81010001 when there isn't a certificate at 0x01c00001. For simplicity,
I've chosen to use a single handle for the EK regardless of which profile
it is created with.
The "TCG EK Credential Profile For TPM Family 2.0" spec also provides a
way for endorsement keys to be certified with non-standard templates by
storing the template in a NV index. This is also supported.
The EK creation is not executed with tpm2-setup --early, as there's no
need for it to be created so early, unlike with the SRK. I also haven't
stored EKpub in /var/lib/systemd like with the SRKpub, as I'm not sure
there will be a use case for this yet.
A follow-up PR may be needed to add some internal helpers to make use
of the persisted EK, as use of low-range EKs requires a policy session.
High-range EKs can be used with a HMAC session because they have the
userWithAuth attribute set and we are creating them with an empty
authorization value.
https://trustedcomputinggroup.org/resource/http-trustedcomputinggroup-org-wp-content-uploads-tcg-ek-credential-profile/https://trustedcomputinggroup.org/resource/tcg-tpm-v2-0-provisioning-guidance/https://trustedcomputinggroup.org/resource/registry/
systemd-dissect --mtree calls io.systemd.PCRExtend over Varlink to extend
the verity NvPCR after activation, and the test then diffs the measure
log to find the new entry. But systemd-pcrextend.socket has
ConditionSecurity=measured-os, which fails when the firmware did not
initialize PCRs, so the test fails.
[ 10.056930] systemd[1]: systemd-pcrextend.socket - TPM PCR Measurements skipped, unmet condition check ConditionSecurity=measured-os
Follow-up for 521a523ce0
The test leaves a lot of state around, and when the test is re-run,
for example due to the qemu bug that makes a VM reboot instead of
shutting down, it fails.
Do more cleanups in the traps.
[ 162.642175] TEST-70-TPM2.sh[2815]: Calculated public key name: 000b2b66edc3a466e81059286aaf38d09ea42a7a9dcdf6ba3b664c62f0cae4ce4f66
[ 162.642628] TEST-70-TPM2.sh[2815]: PolicyAuthorize calculated digest: 2caa740101f65734d50395d6abc64fa46015d40d1f5de239434578544e592a92
[ 162.643681] TEST-70-TPM2.sh[2815]: Calculated NV index name: 000b439cfa1534815bbe8d33b80c56f5a8d17d36fe94a7782b23a37b50def5fc5eaa
[ 162.645111] TEST-70-TPM2.sh[2815]: PolicyAuthorizeNV calculated digest: 69ee0e89fafe6b9df2cd6a5defbf74aa46cf6d92703e645d463549da4ba5e1a4
[ 162.645407] TEST-70-TPM2.sh[2815]: Combined signed PCR policies and pcrlock policies cannot be calculated offline, currently.
[ 162.649576] TEST-70-TPM2.sh[2815]: Releasing crypt device /dev/loop0 context.
[ 162.652433] TEST-70-TPM2.sh[2815]: Releasing device-mapper backend.
[ 162.653518] TEST-70-TPM2.sh[2815]: Closing read only fd for /dev/loop0.
[ 162.654359] TEST-70-TPM2.sh[2815]: Closing read write fd for /dev/loop0.
[ 162.654786] TEST-70-TPM2.sh[2815]: Failed to encrypt device: Operation not supported
Fixes https://github.com/systemd/systemd/issues/38241
in pcrextend we destroy pcr 11, and if we are booted in a kernel that
has pcr11 sigs, we cannot use that signature anymore. hence, let's do
the nvpcr test first, before doing the pcrextend stuff.
Fixes: #39582
Chris Coulson
Lennart Poettering
Luca Boccassi
Daan De Meyer
Lennart Poettering