[PATCH v2 0/7] Add KDF implementations to crypto API

[Stephan Müller]

Hi,

The key derviation functions are considered to be a cryptographic
operation. As cryptographic operations are provided via the kernel
crypto API, this patch set consolidates the KDF implementations into the
crypto API.

The KDF implementations are provided as service functions. Yet, the
interface to the two provided KDFs are identical with the goal to allow
them to be transformed into a crypto API template eventually.

The KDFs execute a power-on self test with test vectors from commonly
known sources.

Tbe SP800-108 KDF implementation is used to replace the implementation
in the keys subsystem. The implementation was verified using the
keyutils command line test code provided in
tests/keyctl/dh_compute/valid. All tests show that the expected values
are calculated with the new code.

The HKDF addition is used to replace the implementation in the filesystem
crypto extension. This code was tested by using an EXT4 encrypted file
system that was created and contains files written to by the current
implementation. Using the new implementation a successful read of the
existing files was possible and new files / directories were created
and read successfully. These newly added file system objects could be
successfully read using the current code. Yet if there is a test suite
to validate whether the invokcation of the HKDF calculates the same
result as the existing implementation, I would be happy to validate
the implementation accordingly.

Changes v2:

* change HKDF function names
* change HKDF/SP800-108 KDF extract / seed function prototype
* ensure clearing of memory of destination buffer in KDF implementation
  if KDF operation fails
* security DH: split the removal of dead code into separate patch

Stephan Mueller (7):
  crypto: Add key derivation self-test support code
  crypto: add SP800-108 counter key derivation function
  crypto: add RFC5869 HKDF
  security: DH - remove dead code for zero padding
  security: DH - use KDF implementation from crypto API
  fs: use HKDF implementation from kernel crypto API
  fs: HKDF - remove duplicate memory clearing

 crypto/Kconfig                         |  14 ++
 crypto/Makefile                        |   6 +
 crypto/hkdf.c                          | 199 +++++++++++++++++++++++++
 crypto/kdf_sp800108.c                  | 149 ++++++++++++++++++
 fs/crypto/Kconfig                      |   2 +-
 fs/crypto/hkdf.c                       | 103 +++----------
 include/crypto/hkdf.h                  |  48 ++++++
 include/crypto/internal/kdf_selftest.h |  71 +++++++++
 include/crypto/kdf_sp800108.h          |  61 ++++++++
 security/keys/Kconfig                  |   2 +-
 security/keys/dh.c                     | 118 ++-------------
 11 files changed, 586 insertions(+), 187 deletions(-)
 create mode 100644 crypto/hkdf.c
 create mode 100644 crypto/kdf_sp800108.c
 create mode 100644 include/crypto/hkdf.h
 create mode 100644 include/crypto/internal/kdf_selftest.h
 create mode 100644 include/crypto/kdf_sp800108.h

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2.26.2