systemd-cryptsetup supports a FIDO2 mode with manual parameters, where
the user provides all the information necessary for recreating the
secret, such as: credential ID, relaying party ID and the salt. This
feature works great for implementing 2FA schemes, where the salt file
is for example a secret unsealed from the TPM or some other source.
While the unlocking part is quite straightforward to set up, enrolling
such a keyslot - not so easy. There is no clearly documented
way on how to set this up and online resources are scarce on this topic
too. By implementing a straightforward way to enroll such a keyslot
directly from systemd-cryptenroll we streamline the enrollment process
and reduce chances for user error when doing such things manually.
- drop unnecessary SYNTHETIC_ERRNO() when the logger does not propagate
error code,
- drop unnecessary '%m' in error message when the error code is
specified with SYNTHETIC_ERRNO(),
- add missing full stop at the end of log message,
- use RET_GATHER(),
- add missing ", ignoring.",
- upeercase the first letter, etc., etc...
With 1df4b21abd we started to default to
enrolling into the LUKS device backing the root fs if none was specified
(and no wipe operation is used). This changes to look for /var/ instead.
On most systems /var/ is going to be on the root fs, hence this change
is with little effect.
However, on systems where / and /var/ is separate it makes more sense to
default to /var/ because that's where the persistent and variable data
is placed (i.e. where LUKS should be used) while / doesn't really have
to be variable, could as well be immutable, or ephemeral. Hence /var/
should be a safer default.
Or to say this differently: I think it makes sense to support systems
with /var/ being on / well. I also think it makes sense to support
systems with them being separate, and /var/ being variable and
persistent. But any other kind of system I find much less interesting to
support, and in that case people should just specify the device name.
Also, while we are at it, tighten the checks a bit, insist on a dm-crypt
+ LUKS superblock before continuing.
And finally, let's print a short message indicating the device we
operate on.
systemd-cryptenroll uses the READ_FULL_FILE_CONNECT_SOCKET flag when
reading the keyfile to also allow reading it from a socket. But it also
sets the offset to 0, causing an unnecessary seek to the beginning of
the newly opened keyfile and disables socket support again, as these do
not support seeking.
Disable seeking entirely to remove the unneeded seek and restore support
for reading the keyfile from a socket again as with systemd-cryptsetup.
Let's define the same switches and their backing variables in the same
order, and let's make sure the enums and switches are named the same.
No actual code changes.
Instead of enrolling the local TPM to a luks volume, use the public key from a
TPM to enroll it into the luks volume. This is useful when enrolling a TPM that
is not currently accessible, for example if the TPM is located on a different
system.
If `--tpm2-public-key=` is not specified, but `tpm2-pcr-public-key.pem` exists
in /{etc,run,usr/lib}/systemd/, the default PCR 11 is not being set.
Fixes 9e437994
Let's switch the order in which we process positional arguments and
analyze/tweak detail parameters. Let's look at the positional arguments
first (i.e. the "big picture") and then look at the switches (i.e.
"little details").
THis doesn't matter much, but makes for better error messages I think.
At least I was very confused that a completely borked cmdline I passed
to cryptenrolled complained about some detail and let the major fuckup
pass...
This removes a duplicate condition check by adding a common surrounding
if block.
This also change a confusing if check: "(X && Y) && Z" to simply "X && Y && Z"
I always found it confusing that most of our TPM related definitions are
in tpm2-util.h, but the PCR names in tpm-pcr.h, without the "2". Let's
fix that and make this systematic, in particular as the definitions in
the file all start with TPM2_ already.
No code flow changes, just some renaming.
We so far maintained two places for symboic names for PCRs. One in
tpm2-util.h and one in tpm-pcr.h.
Let's unify this into one, i.e. move the full list from tpm2-util.h into
tpm-pcr.h, replacing the short list placed so far there.
Systematically prefix the definitions with TPM2_ or tpm2_, to follow how
we do this for all other defines in this context.
No change in behaviour, just unification of tables.
Move the calculation of the sealed object policy hash out of the tpm2_seal()
function. Instead, callers of tpm2_seal() can directly call
tpm2_calculate_sealing_policy() and then provide the policy hash to
tpm2_seal().
In order to allow users to specify expected PCR values, change the
tpm2_parse_pcr_argument() to parse the text argument into an array of
Tpm2PCRValue objects, which provide not only the selected PCR indexes, but also
(optionally) the hash algorithm and hash value for each PCR index.
The systemd-cryptenroll man page states:
Takes a comma separated list of numeric slot indexes, or the special
strings ..., or any combination of these strings or numeric
indexes, in which case all slots matching either are wiped.
but we'd allow only one special string at any given time as the value
was not ORed when assigning. So, for example, --wipe=recovery,password
would actually become --wipe=password, etc.
This allows FIDO2 users to wipe out password slots and still be able to
enroll new key slots via systemd-cryptenroll. Note that when the user
wants to both unlock with a FIDO2 token and enroll a new FIDO2 token,
they cannot be set to automatic discovery. This is to safeguard against
confusion, because there will be multiple tokens connected to the system
when doing so -- and we require users to explicitly confirm which one to
use for unlocking and which one to use for enrollment.
Addresses #20230 for the FIDO2 case.
Add a new tpm2_parse_pcr_argument() helper that unifies how we merge PCR
masks in a single function, we can use all over the place. Previously we
had basically the same code for this at 4 places.
Yu Watanabe
Lennart Poettering
Kamil Szczęk
Sam Leonard
Daan De Meyer
Mike Yuan
Luca Boccassi
Ludwig Nussel
Felix Riemann
Gabríel Arthúr Pétursson
Cristian Rodríguez
Dan Streetman
Antonio Alvarez Feijoo
Zbigniew Jędrzejewski-Szmek
Frantisek Sumsal
Peter Cai
Jan B
MkfsSion