Let's make sure that user's cannot DoS services for other users so
easily, and enable MaxConnectionsPerSocket= by default for all of them.
Note that this is mostly paranoia for systemd-pcrextend.socket and
systemd-sysext.socket: the socket is only accessible to root anyway,
hence the accounting shouldn#t change anything. But this is just a
safety net, in preparation that we open up some functionality of these
services sooner or later.
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
This is primarily supposed to be a 1st step with varlinkifying our
various command line tools, and excercise in how this might look like
across our codebase one day. However, at AllSystemsGo! 2023 it was
requested that we provide an API to do a PCR measurement along with a
matching event log record, and this provides that.
Lennart Poettering