NIST SP 800-131Ar2, section 8 "Deriving Additional Keys from
a Cryptographic Key" says that for KDFs defined in SP 800-108, "[t]he
length of the key-derivation key shall be at least 112 bits". It further
specifies that HMAC-based KDFs "with a key whose length is at least 112
bits" are acceptable.
Add an explicit indicator for SP 800-108 KDFs that will mark shorter key
lengths as unapproved. The indicator can be queried from the EVP_KDF_CTX
object using EVP_KDF_CTX_get_params() with the
OSSL_KDF_PARAM_REDHAT_FIPS_INDICATOR
parameter.
This also modifies the previously applied HKDF indicator patch to use
the same interface to query its FIPS indicator. This provides better
consistency across the various KDFs with explicit indicators.
Additionally, the new constants are clearly marked as being specific to
Red Hat.
Signed-off-by: Clemens Lang <cllang@redhat.com>
Resolves: rhbz#2144019
