The updated parsing_hacks.h file uncovered a bunch of extra
things that the check-pointer-deref coccinelle script flags.
This commit fixes them to make the tree check-pointer-deref clean.
In many cases it's essential to know if the firmware supports a TPM, but
in others we should accept it if the firmware doesn't have TPM support,
in particular if we want to run the OS with a software TPM.
Hence, add tpm2_is_mostly_supported() as function similar to
tpm2_is_fully_supported(), with the only difference that the former
doesn't insist on a firmware supported TPM. Then, change a number of
users over to this (but not all).
We want to start the software TPM fallback only if no real hw is
evailable and if the user opts-in to this behaviour. Add a generator
that drives all this, based on kernel command line configuration.
For TPM-less systems it's sometimes valuable to have a fill-in software
TPM running from early boot on, so that TPM-based functionality can
"just work" and rely on TPM semantics, even if it's at a substantially
weaker security level.
This adds a wrapper around swtpm. It's a binary that chainloads swtpm
but does a few preparatory steps and integrates into systemd's logic
otherwise.
All this is then exposed as systemd-tpm2-swtpm.service.
The service is not hooked into much yet, that is added in later commits.
Let's bubble up failures all the way until they reach the services, but
then let's carefully gracefully handle some of them, that are about
issues not immediately actionable to the admin, even if they are
potentially quite problematic.
I thnk it's crucial we start to measure Verity images as we activate
them, so that the event log has a full trace of the compisition of the
system. hence let's introduce a new NvPCR for this purpse, under the
name "verity".
We'd like to measure various additional things into PCRs, but all
available ones to the OS are already used for various purposes. Hence,
let's introduce a new concept of "NV Index based PCRs", i.e. let's use
TPM2 nv indexes of type TPM2_NT_EXTEND that mostly behave like real
PCRs, but which we can allocate relatively freely from the nv index
space. Let's call these "fake" PCRs "NvPCRs".
My original intention was to get a fixed NV index range assigned from
the TCG, either for Linux or for systemd as a project, but this stalled
with no further updates from the TCG for more than a year and a half
now. I was told an NV index range to use though, even if it never was
officially assigned, hence this PR uses this by default. But the range
is configurable at build time, on purpose, so that downstreams have some
flexibility to change this if they want. To abstract the actual nvindex
number away we introduce a naming concept, so that nvindexes are
referenced by name string rather than number.
NvPCRs are defined in little JSON snippets in /usr/lib/nvpcr/*.nvpcr,
that match up index number and name, as well as pick a hash algorithm.
There's one complication: these nvindex (like any nvindex) can be
deleted by anyone with access to the TPM, and then be recreated. This
could be used to reset the NvPCRs to zero during runtime, which defeats
the whole point of them. Our way out: we measure a secret as first thing
after creation into the NvPCRs. (Or actually, we measure a per-NvPCR
secret we derive from a system secret via an HMAC of the NvPCR name) and
the nvindex handle). This "anchoring" secret is stored in /run/ +
/var/lib/ + ESP/XBOOTLDR (the latter encrypted as credential, locked to
the TPM), to make it available at the whole runtime of the OS.
The tpm2-clear units are only installed if tpm/bootloader/ssl are
enabled. The tpm2-setup binary/units are built and installed only
if tpm/bootloader/ssl are enabled.
Do the same for the tpm2-clear binary to keep it consistent.
Let's always make sure the temporary file returned by fopen_tmpfile()
and friends is removed on failure (via _cleanup_). Conversely, make sure
that once the file is renamed into its final place, we no longer try to
remove the temporary file (since it's not going to exist anymore).
This commit cleans up the includes for all the small tools across
the tree.
A few cases of returning EXIT_SUCCESS are replaced with returning
0 to avoid including <stdlib.h>.
Split out of #37344.
Now that the necessary functions from log.h have been moved to macro.h,
we can stop including log.h in macro.h. This requires modifying source
files all over the tree to include log.h instead.
This introduce LOG_ITEM() macro that checks arbitrary formats in
log_struct().
Then, drop _printf_ attribute from log_struct_internal(), as it does not
help so much, and compiler checked only the first format string.
Hopefully, this silences false-positive warnings by Coverity.
@poettering hrm, there's still one thing unclear to me: we currently
have no way for canceling factory reset via IPC. And adding that to
varlink service solely doesn't seem feasible either, since the state
departs from the active state of `factory-reset.target` and it would
become impossible to re-request it without restarting
`factory-reset.target` _and all dependencies_, which feels
unmaintainable.
The immediately following flink_tmpfile() does that anyway, hence no
need to do so explicitly beforehand.
(Also the log message was wrong: it says "sync" but here we "flush",
which is a much weaker operation)
The TPM might be password/pin protected for various reasons even if
there is no SRK yet. Let's handle those cases gracefully instead of
failing the unit as it is enabled by default.
We so far just print a short log message that is not very useful, let's
add some recognizable error codes, and output better log messages if we
can't get TPM stuff to work.
Fixes: #31925
Currently the associated units fail if full tpm support is not available
on the system. Similar to systemd-pcrextend, let's add a --graceful option
that exits gracefully if no full TPM support is detected and use it in both
units.
Most of our kernel cmdline options use underscores as word separators in
kernel cmdline options, but there were some exceptions. Let's fix those,
and also use underscores.
Since our /proc/cmdline parsers don't distinguish between the two
characters anyway this should not break anything, but makes sure our own
codebase (and in particular docs and log messages) are internally
consistent.
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 man page doesn't even mention errno. It just says that ferror() should
be used to check for errors. Those writes are unlikely to fail, but if they
do, errno might even be 0. Also, we have fflush_and_check() which does
additional paranoia around errno, because we apparently do not trust that
errno will always be set correctly.
We already save it in PEM format, also store it TPM2_PUBLIC format next
to it. This is useful for usage with systemd-cryptenroll's
--tpm2-device-key= switch.
Michael Vogt
Zbigniew Jędrzejewski-Szmek
Lennart Poettering
Yu Watanabe
Daan De Meyer
Lennart Poettering
Luca Boccassi
Mike Yuan
Zbigniew Jędrzejewski-Szmek
Frantisek Sumsal