This allows loading the X.509 certificate from an OpenSSL provider
instead of a file system path. This allows loading certficates directly
from hardware tokens instead of having to export them to a file on
disk first.
Currently in mkosi and ukify we use sbsigntools to do secure boot
signing. This has multiple issues:
- sbsigntools is practically unmaintained, sbvarsign is completely
broken with the latest gnu-efi when built without -fshort-wchar and
upstream has completely ignored my bug report about this.
- sbsigntools only supports openssl engines and not the new providers
API.
- sbsigntools doesn't allow us to cache hardware token pins in the
kernel keyring like we do nowadays when we sign stuff ourselves in
systemd-repart or systemd-measure
There are alternative tools like sbctl and pesign but these do not
support caching hardware token pins in the kernel keyring either.
To get around the issues with sbsigntools, let's introduce our own
tool systemd-sbsign to do secure boot signing. This allows us to
take advantage of our own openssl infra so that hardware token pins
are cached in the kernel keyring as expected and we get openssl
provider support as well.
While for engines we have ENGINE_ctrl() to set the UI method for the
second PIN prompt, for openssl providers we don't have such a feature
which means we get the default openssl UI for the second pin prompt.
Instead, let's set the default UI method which does get used for the
second pin prompt by the pkcs11 provider.
In mkosi, we want to support signing via a hardware token. We already
support this in systemd-repart and systemd-measure. However, if the
hardware token is protected by a pin, the pin is asked as many as 20
times when building an image as the pin is not cached and thus requested
again for every operation.
Let's introduce a custom openssl ui when we use engines and providers
and plug systemd-ask-password into the process. With systemd-ask-password,
the pin can be cached in the kernel keyring, allowing us to reuse it without
querying the user again every time to enter the pin.
We use the private key URI as the keyring identifier so that the cached pin
can be shared across multiple tools.
Note that if the private key is pin protected, openssl will prompt both when
loading the private key using the pkcs11 engine and when actually signing the
roothash. To make sure our custom UI is used when signing the roothash, we have
to also configure it with ENGINE_ctrl() which takes a non-owning pointer to
the UI_METHOD object and its userdata object which we have to keep alive so we
introduce a new AskPasswordUserInterface struct which we use to keep both objects
alive together with the EVP_PKEY object.
Because the AskPasswordRequest struct stores non-owning pointers to its fields,
we change repart to store the private key URI as a global variable again instead
of the EVP_PKEY object so that we can use the private key argument as the keyring
field of the AskPasswordRequest instance without running into lifetime issues.
openssl can be built without support for engines or with deprecated
definitions disabled.
This also will not pull in most headers automatically,
so add the rsa.h and ec.h header explicitly.
Remove Engine stuff from the header - it is only needed in one
source file.
Make Engine support dependent on the macros.
It turns out it's mostly PKCS11 that supports the URI format,
and other engines just take files. For example the tpm2-tss-openssl
engine just takes a sealed private key file path as the key input,
and the engine needs to be specified separately.
Add --private-key-source=file|engine:foo|provider:bar to
manually specify how to use the private key parameter.
Follow-up for 0a8264080a
This is preparation for #28891, which adds a bunch more helpers around
"struct iovec", at which point this really deserves its own .c/.h file.
The idea is that we sooner or later can consider "struct iovec" as an
entirely generic mechanism to reference some binary blob, and is the
go-to type for this purpose whenever we need one.
Add function to perform KDF-SS ("concat" KDF).
While Openssl allows a digest, HMAC, or KMAC for the auxiliary function H, this
currently only allows using a digest for H.
Add function to perform key-based (KB) key derivation function (KDF) using
hash-based message authentication code (HMAC).
Also alphabetize openssl-util.c header list, and include string-util.h.
Add function to create openssl pkey from ECC curve and point, and function to
get curve id and x/y point from existing ECC pkey. Also add function to create
new ECC key for specified curve.
Also add DEFINE_TRIVIAL_CLEANUP_FUNC_FULL_MACRO() to handle case when func() is
a macro, not a function symbol; specifically in this case it is used for
OPENSSL_free() which is a macro.
Add function to generate an EVP_PKEY for a specific 'n' and 'e', and function
to get 'n' and 'e' values from existing RSA public key. Also add a function to
generate a new RSA key with a specified number of bits.
Traditionally, TPM2 PCR policies are bound against literal PCR values,
which makes them hard to work with when updating software that is
measured into PCRs: each update will change the PCR values, and thus
break TPM2 policies of existing objects.
Let's improve the situation: let's allow signed PCR policies. Secrets
and other TPM2 objects can be associated with a public key that signs a
PCR policy. Thus, if the signed policy and the public key is presented,
access to the TPM2 object can be granted. This allows a less brittle
handling of updates: for example, whenever a kernel image is updated a
new signed PCR policy can be shipped along with it, signed by a private
key owned by the kernel vendor (ideally: same private key that is used
to sign the kernel image itself). TPM2 objects can then be bound to the
associated public key, thus allowing objects that can only be unlocked
by kernels of the same vendor. This makes it very easy to update kernels
without affecting locked secrets.
This does not hook up any of the consuming code (just passes NULL/0
everywhere). This is for later commits.
We get warnings for RSA_free(), EC_KEY_free(), EC_KEY_new(), etc. Those
functions are now deprecated and we're supposed to use the new "EVP API" that
is all the rage in openssl 3.0.
With some effort I converted dnssec_rsa_verify_raw() to use the new API. The
code is significantly longer and, if anything, less readable. The EC code is
more complicated and I assume that the EVP API version will be even more
complex. It is possiblet that I'm missing some way to call the new functions in
a better way, but the documentation is abysmal, so it's really hard to figure
out the best way. Of course there are almost no examples, and the ones that are
there are not terribly useful and are also stubs that don't do interesting
things, don't implement error handling, or memory cleanup. I'll submit my
conversion draft as a separate PR. Maybe somebody who knows openssl better
will pick it up and write a proper solution.
For now, let's just use the existing code, but suppress the warnings. The
new version just came out, so it's unlikely that the deprecated functions will
be removed any time soon.
Fixes#21666.
This allows resolved and importd to be built without libgcrypt.
Note that we now say either 'cryptographic library' or 'cryptolib'.
Co-authored-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Let's switch from the low-level SHA256 APIs to EVP APIs. The former are
deprecated on OpenSSL 3.0, the latter are supported both by old
OpenSSL and by OpenSSL 3.0, hence are the better choice.
Fixes: #20775
Getting certificates for dm-verity roothash signing into the trusted
kernel keychain is a royal PITA (means recompiling or rebooting with
shim), hence let's add a minimal userspace PKCS7 validation as well.
The mechanism is really simple and compatible with the verification the
kernel does. The only difference is that the certificates are searched
in /etc/verity.d/*.crt (and similar dirs in /usr/lib/, …).
We'll first try validation by passing the PKCS#7 data to the kernel, but
if that doesn't work we'll see if one of the certificates found that way
works and then attempt to attach the image without passing the PKCS#7
data to the kernel.
This makes it very easy to have fully validated GPT disk images. For
example, just copy the 'mkosi.secure-boot.crt' file you have in your
mkosi build dir to /etc/verity.d/ and things should just work.
If the cleanup function returns the appropriate type, use that to reset the
variable. For other functions (usually the foreign ones which return void), add
an explicit value to reset to.
This causes a bit of code churn, but I think it might be worth it. In a
following patch static destructors will be called from a fuzzer, and this
change allows them to be called multiple times. But I think such a change might
help with detecting unitialized code reuse too. We hit various bugs like this,
and things are more obvious when a pointer has been set to NULL.
I was worried whether this change increases text size, but it doesn't seem to:
-Dbuildtype=debug:
before "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494520 Feb 16 15:06 build/systemd*
after "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494576 Feb 16 15:10 build/systemd*
now:
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494640 Feb 16 15:15 build/systemd*
-Dbuildtype=release:
before "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:09 build-rawhide/systemd*
after "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:10 build-rawhide/systemd*
now:
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:16 build-rawhide/systemd*
I would expect that the compiler would be able to elide the setting of a
variable if the variable is never used again. And this seems to be the case:
in optimized builds there is no change in size whatsoever. And the change in
size in unoptimized build is negligible.
Something strange is happening with size of libsystemd: it's bigger in
optimized builds. Something to figure out, but unrelated to this patch.
Daan De Meyer
Norbert Lange
Luca Boccassi
Vladimir Stoiakin
Lennart Poettering
Dan Streetman
Zbigniew Jędrzejewski-Szmek
Kevin Kuehler
Yu Watanabe