LLVM 13 introduced `-Wunused-but-set-variable` diagnostic flag, which
trips over some intentionally set-but-not-used variables or variables
attached to cleanup handlers with side effects (`_cleanup_umask_`,
`_cleanup_(notify_on_cleanup)`, `_cleanup_(restore_sigsetp)`, etc.):
```
../src/basic/process-util.c:1257:46: error: variable 'saved_ssp' set but not used [-Werror,-Wunused-but-set-variable]
_cleanup_(restore_sigsetp) sigset_t *saved_ssp = NULL;
^
1 error generated.
```
Previously, we hardcoded use of ECC as primary keys, since they are much
faster (i.e. saving multiple seconds) to do TPM2 operations with. Alas,
not all TPM2 chips appear to support ECC. Bummer.
Let's hence add a fallback logic: if we can't create an ECC primary key,
use an RSA key, and store that fact away.
AFIU the security guarantees should be roughly the same, it's just that
RSA primary keys is so much slower to work with than ECC.
The primary key algorithm is used is stored in the JSON header of LUKS
disks, in a new field. If the field is absent we assume to use ECC, to
provide full compatibility with old systemd versions.
The primary key algorithm is stored in a new field in the credentials
file format (in fact, a previously unused zero space is used), too.
Hopefully, this should ensure that TPM2 support will "just work" on more
systems.
Fixes: #20361
Add support for systemd-pkcs11 based LUKS2 device activation
via libcryptsetup plugin. This make the feature (pkcs11 sealed
LUKS2 keyslot passphrase) usable from both systemd utilities
and cryptsetup cli.
The feature is configured via -Dlibcryptsetup-plugins combo
with default value set to 'auto'. It get's enabled automatically
when cryptsetup 2.4.0 or later is installed in build system.
Add support for systemd-fido2 based LUKS2 device activation
via libcryptsetup plugin. This make the feature (fido2 sealed
LUKS2 keyslot passphrase) usable from both systemd utilities
and cryptsetup cli.
The feature is configured via -Dlibcryptsetup-plugins combo
with default value set to 'auto'. It get's enabled automatically
when cryptsetup 2.4.0 or later is installed in build system.
Previously, we'd encode PCR policies strictly with the SHA256 PCR bank
set. However, as it appears not all hw implement those. Sad.
Let's add some minimal logic to auto-detect supported PCR banks: if
SHA256 is supported, use that. But if not, automatically fall back to
SHA1.
This then changes both the LUKS code, and the credentials code to
serialize the selected bank, along with the rest of the data in order to
make this robust.
This extends the LUK2 JSON metadata in a compatible way. The credentials
encryption format is modified in an incompatible way however, but given
that this is not part of any official release should be OK.
Fixes: #20134
Add support for systemd-tpm2 based LUKS2 device activation
via libcryptsetup plugin. This make the feature (tpm2 sealed
LUKS2 keyslot passphrase) usable from both systemd utilities
and cryptsetup cli.
The feature is configured via -Dlibcryptsetup-plugins combo
with default value set to 'auto'. It get's enabled automatically
when cryptsetup 2.4.0 or later is installed in build system.
Seems the assert should be placed in-before decrypted_key
pointer is passed to libcryptsetup API.
Original placement would trigger abort in case tpm2
hw was not present in the system while required
to activate crypt devices.
Use the option name 'password-echo' instead of the generic term
'silent'.
Make the option take an argument for better control over echoing
behavior.
Related discussion in https://github.com/systemd/systemd/pull/19619
Note that this means EFI-systems with a manually added TPM device won't
be supported automatically, but given that the TPM2 trust model kinda
requires firmware support I doubt it matters supporting this. And in all
other cases it speeds things up a bit.
Code using libcryptsetup already sets the global log function if it uses
dlopen_cryptsetup(). Make sure we do the same for the three programs
that explicitly link against libcryptsetup and hence to not use
dlopen_cryptsetup().
Let's improve compatibility with systemd 248 enrollments of FIDO2 keys:
if we have no information about the up/uv/pin settings, let's try to
determine them automatically, i.e. use up and pin if needed.
This only has an effect on LUKS2 volumes where a FIDO2 key was enrolled
with systemd 248 and thus the JSON data lacks the up/uv/pin fields. It
also matters if the user configured FIDO2 parameters explicitly via
crypttab options, so that the JSON data is not used.
For newer enrollments we'll stick to the explicit settings, as that's
generally much safer and robust.
Adds a crypttab option 'silent' that enables the AskPasswordFlag
ASK_PASSWORD_SILENT. This allows usage of systemd-cryptsetup to default
to silent mode, rather than requiring the user to press tab every time.
FLAGS_SET() checks if *all* the bits are set. In this case we want to check
if *any* are. FLAGS_SET() was added in cde2f8605e,
but not a bug then yet, because with just one bit, both options are equivalent.
But when more bits were added later, this stopped being correct.
Fixup for cde2f8605e. Use PIN+PV because the
status quo ante was that we turned off "uv" and left "up" and "clientPin" in
its default values, which with yubikeys (i.e. the most popular hardware) meant
both "up" and "clientPin" were enabled by default.
Coverity CID#1453085.
Some tokens support authorization via fingerprint or other biometric
ID. Add support for "user verification" to cryptenroll and cryptsetup.
Disable by default, as it is still quite uncommon.
In some cases user presence might not be required to get _a_
secret out of a FIDO2 device, but it might be required to
the get actual secret that was used to lock the volume.
Record whether we used it in the LUKS header JSON metadata.
Let the cryptenroll user ask for the feature, but bail out if it is
required by the token and the user disabled it.
Enabled by default.
Closes: https://github.com/systemd/systemd/issues/19246
Some FIDO2 devices allow the user to choose whether to use a PIN or not
and will HMAC with a different secret depending on the choice.
Some other devices (or some device-specific configuration) can instead
make it mandatory.
Allow the cryptenroll user to choose whether to use a PIN or not, but
fail immediately if it is a hard requirement.
Record the choice in the JSON-encoded LUKS header metadata so that the
right set of options can be used on unlock.
On headless setups, in case other methods fail, asking for a password/pin
is not useful as there are no users on the terminal, and generates
unwanted noise. Add a parameter to /etc/crypttab to skip it.
This adds generic support for the SetCredential=/LoadCredential= logic
to our password querying infrastructure: if a password is requested by a
program that has a credential store configured via
$CREDENTIALS_DIRECTORY we'll look in it for a password.
The "systemd-ask-password" tool is updated with an option to specify the
credential to look for.
I think this formatting was originally used because it simplified
adding new options to the help messages. However, these days, most
tools their help message end with "\nSee the %s for details.\n" so
the final line almost never has to be edited which eliminates the
benefit of the custom formatting used for printf() help messages.
Let's make things more consistent and use the same formatting for
printf() help messages that we use everywhere else.
Prompted by https://github.com/systemd/systemd/pull/18355#discussion_r567241580
This commit adds support for disabling the read and write
workqueues with the new crypttab options no-read-workqueue
and no-write-workqueue. These correspond to the cryptsetup
options --perf-no_read_workqueue and --perf-no_write_workqueue
respectively.
Optionally, embedd PKCS#11 token URI and encrypted key in LUKS2 JSON
metadata header. That way it becomes very easy to unlock properly set up
PKCS#11-enabled LUKS2 volumes, a simple /etc/crypttab line like the
following suffices:
mytest /dev/disk/by-partuuid/41c1df55-e628-4dbb-8492-bc69d81e172e - pkcs11-uri=auto
Such a line declares that unlocking via PKCS#11 shall be attempted, and
the token URI and the encrypted key shall be read from the LUKS2 header.
An external key file for the encrypted PKCS#11 key is hence no longer
necessary, nor is specifying the precise URI to use.
It's highly confusing to reference the command line parameters via
argv[] indexes. Let's clean this up, and introduce properly named local
variables that make this easier to follow.
No actualy code changes, just some renaming of variables.
Let's move the 3rd way how cryptsetup acquires key files to
read_file_full() too.
Since load_key_file()'s raison d'etre now is just the search path logic,
let's rename the function to find_key_file().
Previously, we'd load the file with libcryptsetup's calls. Let's do that
in our own, so that we can make use of READ_FULL_FILE_CONNECT_SOCKET,
i.e. read in keys via AF_UNIX sockets, so that people can plug key
providers into our logic.
This provides functionality similar to Debian's keyscript= crypttab
option (see → #3007), as it allows key scripts to be run as socket
activated services, that have stdout connected to the activated socket.
In contrast to traditional keyscript= support this logic runs stuff out
of process however, which is beneficial, since it allows sandboxing and
similar.
Frantisek Sumsal
Lennart Poettering
Ondrej Kozina
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Sebastian Blunt
Luca Boccassi
Daan De Meyer
Jonathan G. Underwood