This updates systemd-tpm2-setup to create and persist an endorsement
key if there isn't one already. For each supported EK template profile,
it will read the EK certificate from its NV index if there is one.
When there is an EK certificate present, a primary key is created using
the corresponding template. If the resulting EKpub matches the public
key in the certificate, the created EK is persisted and the process is
complete.
The low-range templates and the high-range RSA 2048/3072 and ECC NIST
P256/P384 storage templates are supported, as detailed in section
5.3 of the "TCG EK Credential Profile For TPM Family 2.0" spec v2.7.
High-range templates are preferred because these permit EK usage without
requiring knowledge of the authorization value for the endorsement
hierarchy, meaning that, like with the SRK, it is possible to restrict
the usage of the endorsement hierarchy whilst still permitting use of
the persistent EK.
The EK is always persisted at handle 0x81010001. This handle is
reserved in Table 2 of the "TCG TPM v2.0 Provisioning Guidance" spec
v1.0r1.0, although this is only a recommendation. This
handle is within the block of handles reserved for endorsement
primary keys in the "Registry of Reserved TPM 2.0 Handles and
Localities" spec v1.2r1.00. Section 2.3.2 of this specification also
makes a suggestion that there should be a relationship between the EK
certificate NV index and a corresponding persistent EK handle by
using handles at the same offsets within their respective ranges.
However, this contradicts the provisioning guidance spec which reserves
0x81010001 when there isn't a certificate at 0x01c00001. For simplicity,
I've chosen to use a single handle for the EK regardless of which profile
it is created with.
The "TCG EK Credential Profile For TPM Family 2.0" spec also provides a
way for endorsement keys to be certified with non-standard templates by
storing the template in a NV index. This is also supported.
The EK creation is not executed with tpm2-setup --early, as there's no
need for it to be created so early, unlike with the SRK. I also haven't
stored EKpub in /var/lib/systemd like with the SRKpub, as I'm not sure
there will be a use case for this yet.
A follow-up PR may be needed to add some internal helpers to make use
of the persisted EK, as use of low-range EKs requires a policy session.
High-range EKs can be used with a HMAC session because they have the
userWithAuth attribute set and we are creating them with an empty
authorization value.
https://trustedcomputinggroup.org/resource/http-trustedcomputinggroup-org-wp-content-uploads-tcg-ek-credential-profile/https://trustedcomputinggroup.org/resource/tcg-tpm-v2-0-provisioning-guidance/https://trustedcomputinggroup.org/resource/registry/
Let's translate openssl's errors to proper errnos
where we can instead of returning EIO for everything.
Let's also make log_openssl_errors() public so we can
use it everywhere and migrate the rest of the codebase
to use it.
Fedora has switched to openssl 4, and we generate a Requires dependency
on libcrypto for the systemd-udev subpackage, so preferring openssl-3
does the wrong thing. So the order in the dlopen note needs to be switched.
But in general, we want to get rid of openssl-3, so we want to load
openssl-4 in preference. Change the order in both places.
(The "compat" order can stay in 261-stable for other distros.)
OpenSSL 4 broke ABI, so we need to look for both SONAMEs.
Try libcrypto.so.3 first, and fallback to libcrypto.so.4,
so that the older and more stable version is used if both
are installed, giving distros time to fix regressions.
This macro emits an SD_ELF_NOTE_DLOPEN note so that calling sites,
and not just libsystemd-shared, get the ELF stamped with the notes
documenting the dependency. Currently most of the dlopen notes end
up in libsystemd-shared, and executables have no way to document
the optional dependencies they need. With this new macro, this
issue can be fixed.
Co-developed-by: Claude Opus 4.8 <noreply@anthropic.com>
RSA PKCS#1 v1.5 is vulnerable to Bleichenbacher-style padding oracle
attacks, albeit very difficult and unlikely to actually happen in the
real world. Still for hardedning, switch new enrollments to RSA-OAEP,
with SHA-256 preferred and SHA-1 as fallback (probed at enrollment time,
since e.g. SoftHSM only accepts SHA-1, and older token might as well).
The actual padding scheme used to wrap a given key is recorded as a new
optional 'pkcs11-padding' / 'padding' field in the LUKS2 token JSON and
the homed user record. Decryption defaults to PKCS#1 v1.5 when absent so
existing enrollments keep working.
Until now OpenSSL was linked into every binary and library that needed
cryptography, pulling libcrypto (and, for resolved, libssl) into the
address space of services that never touch them at runtime. This commit
moves all OpenSSL usage behind the same dlopen helper pattern that we
already use for other optional libraries (libpam, libseccomp, libxz, …)
so libcrypto/libssl are only loaded on demand.
The bulk of the work lives in src/shared/crypto-util.{c,h} (libcrypto)
and src/shared/ssl-util.{c,h} (libssl), which replace the previous
src/shared/openssl-util.{c,h}:
- crypto-util.{c,h} declares every libcrypto function we call via
DLSYM_PROTOTYPE() and resolves them inside dlopen_libcrypto().
- ssl-util.{c,h} holds the libssl-specific DLSYM_PROTOTYPEs,
dlopen_libssl(), and the SSL_freep cleanup helper, so translation
units that only need libcrypto do not pull in libssl declarations.
- Callers refer to the symbols through sym_* aliases rather than the
original names.
- Convenience macros that used to be provided by the OpenSSL headers
(OPENSSL_free, BN_num_bytes, the sk_TYPE_* helpers, …) are
reimplemented as sym_* wrappers so no code path needs to fall back
to the linker-resolved symbols.
- All _cleanup_ helpers are redefined in terms of the sym_* variants
(EVP_PKEY_freep, X509_freep, BIO_freep, …) so cleanup attributes
keep working without pulling in libcrypto symbols at link time.
- The public crypto-util.c entry points (openssl_pubkey_from_pem,
openssl_digest_many, openssl_hmac_many, openssl_cipher_many,
kdf_ss_derive, kdf_kb_hmac_derive, rsa_* / ecc_* helpers,
pubkey_fingerprint, digest_and_sign, pkcs7_new, x509_fingerprint,
openssl_extract_public_key, pkey_generate_volume_keys, the load_*
helpers, …) now call dlopen_libcrypto() at entry before touching any
sym_* pointer.
The call sites across the tree have been converted to call
dlopen_libcrypto()/dlopen_libssl() at the appropriate entry point
before their first sym_* use, and to use sym_* variants throughout:
- bootctl, sbsign, measure, pcrlock, pcrextend, tpm2-setup, repart,
cryptsetup, cryptenroll, homectl, homed, homework, keyutil,
sysupdate, creds, import, dissect-image, pe-binary, pkcs11-util,
pkcs7-util, tpm2-util, creds-util. resolved additionally dlopens
libssl for DoT.
The meson build files are updated to depend on libopenssl_cflags (a
new partial dependency that exposes include paths and compile flags
only, not the linker flags) instead of libopenssl for every target that
previously linked against OpenSSL. Nothing links against libcrypto or
libssl directly anymore.
A new src/sbsign/authenticode.c hosts the Authenticode ASN.1 type
definitions that used to live inline in sbsign.c. The OpenSSL
ASN1_SEQUENCE / ASN1_CHOICE / IMPLEMENT_ASN1_FUNCTIONS macros expand to
code that references libcrypto symbols directly, so to keep this
translation unit unlinked from libcrypto we redirect ASN1_item_* to
the sym_* variants via #define and wrap the ASN1_*_it() getters (which
appear as constant function pointers in static initializers) in small
trampoline functions that forward to the sym_* pointers at runtime.
test-dlopen-so gains assertions for dlopen_libcrypto and dlopen_libssl
so the dlopen contract is exercised in CI, and the openssl-specific
test was renamed from test-openssl.c to test-crypto-util.c to match
the new header naming.
Chris Coulson
Yu Watanabe
Daan De Meyer
Zbigniew Jędrzejewski-Szmek
Luca Boccassi