This commit makes homework always upload the LUKS volume key into the
kernel keyring. This is different from previous behavior in three
notable ways:
- Previously, we'd only upload if auto-resize was on. In preparation for
upcoming changes, now we always upload
- Previously, we'd upload the user's actual password (or a password
obtained from a FIDO key or similar). Now, we upload the LUKS volume key
itself, to remove a layer of unnecessary indirection.
- Previously, Lock() wouldn't remove the key from the kernel keyring.
This, of course, defeats the purpose of Lock(), so now it removes the
key
This commit also allows the LUKS volume to be unlocked using the volume
key we obtained from the keyring.
We have these pretty macros, let's use them everywhere (so far we mostly
used them for newer additions only).
This PR is mostly an excercise in "perl -p -i -e", but there are some
special cases:
* idn-util.c exposes a function whose prototype in the official library
headers is marked with the "const" attribute, and this apparently does
not propagate along typeof() correctly and then
__builtin_types_compatible_p() fails later because it detects that
prototype and original function don't match in prototype.
* libbpf removed some symbols in newer versions, hence we need to define
some prototypes manually to still be able to build.
* libcryptsetup marked a symbol as deprecated we want to use (knowing it
is deprecated). By using the macros this is detected by the compiler.
We work around it via the usual warning off macros.
Note by using these macros we assume that all symbols are known during
build time. Which might not be the case. We might need to revert this
commit for some symbols if this trips up builds on older distros.
This code doesn't link when gcc+lld is used:
$ LDFLAGS=-fuse-ld=lld meson setup build-lld && ninja -C build-lld udevadm
...
ld.lld: error: src/shared/libsystemd-shared-255.a(libsystemd-shared-255.a.p/cryptsetup-util.c.o):
symbol crypt_token_external_path@@ has undefined version
collect2: error: ld returned 1 exit status
As a work-around, restrict it to developer mode.
Closes https://github.com/systemd/systemd/issues/30218.
I tried to get something similar upstream:
https://gitlab.com/cryptsetup/cryptsetup/-/issues/846
But no luck, it was suggested I use ELF interposition instead. Hence,
let's do so (but not via ugly LD_PRELOAD, but simply by overriding the
relevant symbol natively in our own code).
This makes debugging tokens a ton easier.
Make sure that the sym_xyz function pointers have the types that the
functions we'll assign them have.
And of course, this found a number of incompatibilities right-away, in
particular in the bpf hookup.
(Doing this will trigger deprecation warnings from libbpf. I simply
turned them off locally now, since we are well aware of what we are
doing in that regard.)
There's one return type fix (bool → int), that actually matters I think,
as it might have created an incompatibility on some archs.
Offline encryption can be done without mounting the luks device. For
now we still use loop devices to split out the partition we want to
write to but in a later commit we'll replace this with a regular file.
For offline encryption, we need to keep 2x the luks header size space
free at the end of the partition, so this means our encrypted partitions
will be 16M larger than before.
This splits out the JSON parser used by the systemd-cryptsetup code.
This is preparation for later work to reuse it in the tpm2 cryptsetup
token module, which currently uses a separate but very similar parser
for the same data.
No change in behaviour.
We warn when the operation fails, not when it succeeds. Hence this should be
"<do>_or_<handle failure>", not "<do>_and_<handle failure>". We *could* use
whatever convention we want, but rust and perl are rather consistent in using
the logical convention. We don't care about perl that much, but having a naming
convention inverted wrt. rust would be rather confusing.
Also, pretty much every implementation does similar steps, so add a nice
wrapper which combines opening of the library and loading of the symbols.
Also add missing sentinel attribute in dlopen_or_warn().
No need to benchmark pbkdf when asking for minimal values
anyway.
1000 iterations count is minimum for both LUKS1 and LUKS2
pbkdf2 keyslot parameters according to NIST SP 800-132, ch. 5.2.
Iterations count can not be lower than recommended minimum
when benchmark is disabled. The time_ms member is ignored with
benchmark disabled.
So far we only set the per-crypt_device log functions, but some
libcryptsetup calls we invoke without a crypt_device objects, and we
want those to redirect to our infra too.
Let's make libcryptsetup a dlopen() style dep for PID 1 (i.e. for
RootImage= and stuff), systemd-growfs and systemd-repart. (But leave to
be a regulra dep in systemd-cryptsetup, systemd-veritysetup and
systemd-homed since for them the libcryptsetup support is not auxiliary
but pretty much at the core of what they do.)
This should be useful for container images that want systemd in the
payload but don't care for the cryptsetup logic since dm-crypt and stuff
isn't available in containers anyway.
Fixes: #8249
"crypt-util.c" is such a generic name, let's avoid that, in particular
as libc's/libcrypt's crypt() function is so generically named too that
one might thing this is about that. Let's hence be more precise, and
make clear that this is about cryptsetup, and nothing else.
We already had cryptsetup-util.[ch] in src/cryptsetup/ doing keyfile
management. To avoid the needless confusion, let's rename that file to
cryptsetup-keyfile.[ch].
Adrian Vovk
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Daan De Meyer
Ondrej Kozina
Luca Boccassi