Re: [PATCH v7 0/8] lib/crypto: Add ML-DSA signing

Stefan Berger
2025-11-07T18:33:10Z

On 11/6/25 12:44 PM, David Howells wrote:
> Hi Herbert, Eric, et al.,
>
> Building on the SHA-3 lib-crypto patches now in Eric's tree, here's a set of
> patches does the following:
>
> (1) Add SHAKE-256 crypto_sig support, generating 32-byte fixed output. The
> XOF features aren't available through this. SHAKE-128 crypto_sig support
> isn't required for ML-DSA, so I haven't implemented that at this time.
>
> (2) Add ML-DSA signature verification code, extracted from Stephan Mueller's
> Leancrypto project. It is accessed through crypto_sig.
>
> (3) Add a kunit test in three installments (due to size) to add some
> testing for the three different levels of ML-DSA (44, 65 and 87).
>
> (4) Modify PKCS#7 support to allow kernel module signatures to carry
> authenticatedAttributes as OpenSSL refuses to let them be opted out of
> for ML-DSA (CMS_NOATTR). This adds an extra digest calculation to the
> process.
>
> (5) Modify PKCS#7 to pass the authenticatedAttributes directly to the
> ML-DSA algorithm rather than passing over a digest as is done with RSA
> as ML-DSA wants to do its own hashing and will add other stuff into
> the hash. We could use hashML-DSA or an external mu instead, but they
> aren't standardised for CMS yet.
>
> (6) Add support to the PKCS#7 and X.509 parsers for ML-DSA.
>
> (7) Modify sign-file to handle OpenSSL not permitting CMS_NOATTR with
> ML-DSA.
> > (8) Allow SHA-3 algorithms, including SHAKE256, to be used for
the message
> digest and add ML-DSA to the choice of algorithm with which to sign.

Hi David,

if you are interested in picking patches from my effort in this
direction, let me know. I have a test suite in user space at

https://github.com/stefanberger/mldsa-testing

User space patches interfacing with the kernel (prefix 'keyctl:') are in
this series here:

https://github.com/stefanberger/linux-ima-namespaces/commits/mldsa.10312025/

Either way, great work!

>
> With that, ML-DSA signing appears to work.
>
> This is based on Eric's libcrypto-next branch.
>
> The patches can also be found here:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=keys-pqc
>
> David
>
> Changes
> =======
> ver #7)
> - Rebased on Eric's tree as that now contains all the necessary SHA-3
> infrastructure and drop the SHA-3 patches from here.
> - Added a minimal patch to provide shake256 support for crypto_sig.
> - Got rid of the memory allocation wrappers.
> - Removed the ML-DSA keypair generation code and the signing code, leaving
> only the signature verification code.
> - Removed the secret key handling code.
> - Removed the secret keys from the kunit tests and the signing testing.
> - Removed some unused bits from the ML-DSA code.
> - Downgraded the kdoc comments to ordinary comments, but keep the markup
> for easier comparison to Leancrypto.
>
> ver #6)
> - Added a patch to make the jitterentropy RNG use lib/sha3.
> - Added back the crypto/sha3_generic changes.
> - Added ML-DSA implementation (still needs more cleanup).
> - Added kunit test for ML-DSA.
> - Modified PKCS#7 to accommodate ML-DSA.
> - Modified PKCS#7 and X.509 to allow ML-DSA to be specified and used.
> - Modified sign-file to not use CMS_NOATTR with ML-DSA.
> - Allowed SHA3 and SHAKE* algorithms for module signing default.
> - Allowed ML-DSA-{44,65,87} to be selected as the module signing default.
>
> ver #5)
> - Fix gen-hash-testvecs.py to correctly handle algo names that contain a
> dash.
> - Fix gen-hash-testvecs.py to not generate HMAC for SHA3-* or SHAKE* as
> these don't currently have HMAC variants implemented.
> - Fix algo names to be correct.
> - Fix kunit module description as it now tests all SHA3 variants.
>
> ver #4)
> - Fix a couple of arm64 build problems.
> - Doc fixes:
> - Fix the description of the algorithm to be closer to the NIST spec's
> terminology.
> - Don't talk of finialising the context for XOFs.
> - Don't say "Return: None".
> - Declare the "Context" to be "Any context" and make no mention of the
> fact that it might use the FPU.
> - Change "initialise" to "initialize".
> - Don't warn that the context is relatively large for stack use.
> - Use size_t for size parameters/variables.
> - Make the module_exit unconditional.
> - Dropped the crypto/ dir-affecting patches for the moment.
>
> ver #3)
> - Renamed conflicting arm64 functions.
> - Made a separate wrapper API for each algorithm in the family.
> - Removed sha3_init(), sha3_reinit() and sha3_final().
> - Removed sha3_ctx::digest_size.
> - Renamed sha3_ctx::partial to sha3_ctx::absorb_offset.
> - Refer to the output of SHAKE* as "output" not "digest".
> - Moved the Iota transform into the one-round function.
> - Made sha3_update() warn if called after sha3_squeeze().
> - Simplified the module-load test to not do update after squeeze.
> - Added Return: and Context: kdoc statements and expanded the kdoc
> headers.
> - Added an API description document.
> - Overhauled the kunit tests.
> - Only have one kunit test.
> - Only call the general hash tester on one algo.
> - Add separate simple cursory checks for the other algos.
> - Add resqueezing tests.
> - Add some NIST example tests.
> - Changed crypto/sha3_generic to use this
> - Added SHAKE128/256 to crypto/sha3_generic and crypto/testmgr
> - Folded struct sha3_state into struct sha3_ctx.
>
> ver #2)
> - Simplify the endianness handling.
> - Rename sha3_final() to sha3_squeeze() and don't clear the context at the
> end as it's permitted to continue calling sha3_final() to extract
> continuations of the digest (needed by ML-DSA).
> - Don't reapply the end marker to the hash state in continuation
> sha3_squeeze() unless sha3_update() gets called again (needed by
> ML-DSA).
> - Give sha3_squeeze() the amount of digest to produce as a parameter
> rather than using ctx->digest_size and don't return the amount digested.
> - Reimplement sha3_final() as a wrapper around sha3_squeeze() that
> extracts ctx->digest_size amount of digest and then zeroes out the
> context. The latter is necessary to avoid upsetting
> hash-test-template.h.
> - Provide a sha3_reinit() function to clear the state, but to leave the
> parameters that indicate the hash properties unaffected, allowing for
> reuse.
> - Provide a sha3_set_digestsize() function to change the size of the
> digest to be extracted by sha3_final(). sha3_squeeze() takes a
> parameter for this instead.
> - Don't pass the digest size as a parameter to shake128/256_init() but
> rather default to 128/256 bits as per the function name.
> - Provide a sha3_clear() function to zero out the context.
>
> David Howells (8):
> crypto: Add support for shake256 through crypto_shash
> crypto: Add ML-DSA/Dilithium verify support
> crypto: Add ML-DSA-44 pure rejection test vectors as a kunit test
> crypto: Add ML-DSA-65 pure rejection test vectors as a kunit test
> crypto: Add ML-DSA-87 pure rejection test vectors as a kunit test
> pkcs7: Allow the signing algo to calculate the digest itself
> pkcs7, x509: Add ML-DSA support
> modsign: Enable ML-DSA module signing
>
> Documentation/admin-guide/module-signing.rst | 15 +-
> certs/Kconfig | 24 +
> certs/Makefile | 3 +
> crypto/Kconfig | 1 +
> crypto/Makefile | 1 +
> crypto/asymmetric_keys/pkcs7_parser.c | 19 +-
> crypto/asymmetric_keys/pkcs7_verify.c | 52 +-
> crypto/asymmetric_keys/public_key.c | 7 +
> crypto/asymmetric_keys/x509_cert_parser.c | 24 +
> crypto/ml_dsa/Kconfig | 32 +
> crypto/ml_dsa/Makefile | 20 +
> crypto/ml_dsa/dilithium.h | 547 ++
> crypto/ml_dsa/dilithium_44.c | 33 +
> crypto/ml_dsa/dilithium_44.h | 282 +
> crypto/ml_dsa/dilithium_65.c | 33 +
> crypto/ml_dsa/dilithium_65.h | 282 +
> crypto/ml_dsa/dilithium_87.c | 33 +
> crypto/ml_dsa/dilithium_87.h | 282 +
> crypto/ml_dsa/dilithium_api.c | 429 ++
> crypto/ml_dsa/dilithium_debug.h | 49 +
> crypto/ml_dsa/dilithium_ntt.c | 89 +
> crypto/ml_dsa/dilithium_ntt.h | 35 +
> crypto/ml_dsa/dilithium_pack.h | 119 +
> crypto/ml_dsa/dilithium_poly.c | 377 +
> crypto/ml_dsa/dilithium_poly.h | 181 +
> crypto/ml_dsa/dilithium_poly_c.h | 141 +
> crypto/ml_dsa/dilithium_poly_common.h | 35 +
> crypto/ml_dsa/dilithium_polyvec.h | 343 +
> crypto/ml_dsa/dilithium_polyvec_c.h | 81 +
> .../dilithium_pure_rejection_vectors_44.h | 489 ++
> .../dilithium_pure_rejection_vectors_65.h | 4741 ++++++++++++
> .../dilithium_pure_rejection_vectors_87.h | 6456 +++++++++++++++++
> crypto/ml_dsa/dilithium_reduce.h | 85 +
> crypto/ml_dsa/dilithium_rounding.c | 128 +
> crypto/ml_dsa/dilithium_selftest.c | 142 +
> crypto/ml_dsa/dilithium_service_helpers.h | 99 +
> crypto/ml_dsa/dilithium_sig.c | 334 +
> crypto/ml_dsa/dilithium_signature_c.c | 102 +
> crypto/ml_dsa/dilithium_signature_c.h | 37 +
> crypto/ml_dsa/dilithium_signature_helper.c | 97 +
> crypto/ml_dsa/dilithium_signature_impl.h | 370 +
> crypto/ml_dsa/dilithium_type.h | 102 +
> crypto/ml_dsa/dilithium_zetas.c | 67 +
> crypto/ml_dsa/signature_domain_separation.c | 203 +
> crypto/ml_dsa/signature_domain_separation.h | 30 +
> crypto/sha3.c | 42 +
> include/crypto/public_key.h | 1 +
> include/linux/oid_registry.h | 5 +
> kernel/module/Kconfig | 5 +
> scripts/sign-file.c | 26 +-
> 50 files changed, 17094 insertions(+), 36 deletions(-)
> create mode 100644 crypto/ml_dsa/Kconfig
> create mode 100644 crypto/ml_dsa/Makefile
> create mode 100644 crypto/ml_dsa/dilithium.h
> create mode 100644 crypto/ml_dsa/dilithium_44.c
> create mode 100644 crypto/ml_dsa/dilithium_44.h
> create mode 100644 crypto/ml_dsa/dilithium_65.c
> create mode 100644 crypto/ml_dsa/dilithium_65.h
> create mode 100644 crypto/ml_dsa/dilithium_87.c
> create mode 100644 crypto/ml_dsa/dilithium_87.h
> create mode 100644 crypto/ml_dsa/dilithium_api.c
> create mode 100644 crypto/ml_dsa/dilithium_debug.h
> create mode 100644 crypto/ml_dsa/dilithium_ntt.c
> create mode 100644 crypto/ml_dsa/dilithium_ntt.h
> create mode 100644 crypto/ml_dsa/dilithium_pack.h
> create mode 100644 crypto/ml_dsa/dilithium_poly.c
> create mode 100644 crypto/ml_dsa/dilithium_poly.h
> create mode 100644 crypto/ml_dsa/dilithium_poly_c.h
> create mode 100644 crypto/ml_dsa/dilithium_poly_common.h
> create mode 100644 crypto/ml_dsa/dilithium_polyvec.h
> create mode 100644 crypto/ml_dsa/dilithium_polyvec_c.h
> create mode 100644 crypto/ml_dsa/dilithium_pure_rejection_vectors_44.h
> create mode 100644 crypto/ml_dsa/dilithium_pure_rejection_vectors_65.h
> create mode 100644 crypto/ml_dsa/dilithium_pure_rejection_vectors_87.h
> create mode 100644 crypto/ml_dsa/dilithium_reduce.h
> create mode 100644 crypto/ml_dsa/dilithium_rounding.c
> create mode 100644 crypto/ml_dsa/dilithium_selftest.c
> create mode 100644 crypto/ml_dsa/dilithium_service_helpers.h
> create mode 100644 crypto/ml_dsa/dilithium_sig.c
> create mode 100644 crypto/ml_dsa/dilithium_signature_c.c
> create mode 100644 crypto/ml_dsa/dilithium_signature_c.h
> create mode 100644 crypto/ml_dsa/dilithium_signature_helper.c
> create mode 100644 crypto/ml_dsa/dilithium_signature_impl.h
> create mode 100644 crypto/ml_dsa/dilithium_type.h
> create mode 100644 crypto/ml_dsa/dilithium_zetas.c
> create mode 100644 crypto/ml_dsa/signature_domain_separation.c
> create mode 100644 crypto/ml_dsa/signature_domain_separation.h
>
>