[v6,0/2] New s390 specific protected key hmac

Message

Harald Freudenberger Nov. 29, 2024, 11:10 a.m. UTC

Add support for protected key hmac ("phmac") for s390 arch.

With the latest machine generation there is now support for
protected key (that is a key wrapped by a master key stored
in firmware) hmac for sha2 (sha224, sha256, sha384 and sha512)
for the s390 specific CPACF instruction kmac.

This patch adds support via 4 new hashes registered as
phmac(sha224), phmac(sha256), phmac(sha384) and phmac(sha512).

Please note that as of now, there is no selftest enabled for
these shashes, but the implementation has been tested with
testcases via AF_ALG interface. However, there may come an
improvement soon to use the available clear key hmac selftests.

Changelog:
v1: Initial version
v2: Increase HASH_MAX_DESCSIZE generic (not just for arch s390).
    Fix one finding to use kmemdup instead of kmalloc/memcpy from test
    robot. Remove unneeded cpacf subfunctions checks. Simplify
    clone_tfm() function. Rebased to s390/features.
v3: Feedback from Herbert: Use GFP_ATOMIC in setkey function.
    Feedback from Holger: rework tfm clone function, move convert key
    invocation from setkey to init function. Rebased to updated
    s390/features from 11/7/2024. Ready for integration if there are
    no complains on v3.
v4: Rewind back more or less to v2. Add code to check for non-sleeping
    context. Non-sleeping context during attempt to derive the
    protected key from raw key material is not accepted and
    -EOPNOTSUPP is returned (also currently all derivation pathes
    would in fact never sleep). In general the phmac implementation is
    not to be used within non-sleeping context and the code header
    mentions this. Tested with (patched) dm-integrity - works fine.
v5: As suggested by Herbert now the shashes have been marked as
    'internal' and wrapped by ahashes which use the cryptd if an
    atomic context is detected. So the visible phmac algorithms are
    now ahashes. Unfortunately the dm-integrity implementation
    currently requests and deals only with shashes and this phmac
    implementation is not fitting to the original goal any more...
v6: As suggested by Herbert now a pure async phmac implementation.
    Tested via AF_ALG interface. Untested via dm-integrity as this layer
    only supports shashes. Maybe I'll develop a patch to switch the
    dm-integrity to ahash as it is anyway the more flexible interface.

Harald Freudenberger (1):
  s390/crypto: New s390 specific protected key hash phmac

Holger Dengler (1):
  s390/crypto: Add protected key hmac subfunctions for KMAC

 arch/s390/configs/debug_defconfig |   1 +
 arch/s390/configs/defconfig       |   1 +
 arch/s390/crypto/Makefile         |   1 +
 arch/s390/crypto/phmac_s390.c     | 474 ++++++++++++++++++++++++++++++
 arch/s390/include/asm/cpacf.h     |   4 +
 drivers/crypto/Kconfig            |  12 +
 6 files changed, 493 insertions(+)
 create mode 100644 arch/s390/crypto/phmac_s390.c


base-commit: 3f020399e4f1c690ce87b4c472f75b1fc89e07d5
--
2.43.0