I was looking at the logs in some bug and saw this:
Mar 13 15:55:12 fedora systemd[1]: systemd-pcrmachine.service - TPM2 PCR Machine ID Measurement was skipped because of an unmet condition check (ConditionSecurity=measured-uki).
Mar 13 15:55:12 fedora systemd[1]: Starting systemd-remount-fs.service - Remount Root and Kernel File Systems...
Mar 13 15:55:12 fedora systemd[1]: systemd-tpm2-setup-early.service - TPM2 SRK Setup (Early) was skipped because of an unmet condition check (ConditionSecurity=measured-uki).
This is overly technical, for most units we don't provide this level of
detail about the implementation. So retitle the units to be more accessible.
Also, the fact that it's a v. 2 of the TPM is not that important. We don't
support TPM 1.2, but computers without TPM v2 are getting rare. For other
units we don't advertise the version of hardware, and let's not do this here,
to reduce some complexity.
Distributions apparently only compile a subset of TPM2 drivers into the
kernel. For those not compiled it but provided as kmod we need a
synchronization point: we must wait before the first TPM2 interaction
until the driver is available and accessible.
This adds a tpm2.target unit as such a synchronization point. It's
ordered after /dev/tpmrm0, and is pulled in by a generator whenever we
detect that the kernel reported a TPM2 to exist but we have no device
for it yet.
This should solve the issue, but might create problems: if there are TPM
devices supported by firmware that we don't have Linux drivers for we'll
hang for a bit. Hence let's add a kernel cmdline switch to disable (or
alternatively force) this logic.
Fixes: #30164
The tool initially just measured the boot phase, but was subsequently
extended to measure file system and machine IDs, too. At AllSystemsGo
there were request to add more, and make the tool generically
accessible.
Hence, let's rename the binary (but not the pcrphase services), to make
clear the tool is not just measureing the boot phase, but a lot of other
things too.
The tool is located in /usr/lib/ and still relatively new, hence let's
just rename the binary and be done with it, while keeping the unit names
stable.
While we are at it, also move the tool out of src/boot/ and into its own
src/pcrextend/ dir, since it's not really doing boot related stuff
anymore.
Some of the new units using systemd-pcrphase are missing the --graceful
flag which causes them to error if the tpm libraries are not installed.
Add --graceful just like in the other pcrphase units to make systemd-pcrphase
exit gracefully if the tpm libraries are missing.
These units are also present in the initrd, so instead of an assert,
just use a condition so they are skipped where they need to be skipped.
Fixes https://github.com/systemd/systemd/issues/26358
