Re: [PATCH v13 01/12] crypto: Add ML-DSA crypto_sig support

Jarkko Sakkinen
2026-01-20T17:37:56Z

On Tue, Jan 20, 2026 at 02:50:47PM +0000, David Howells wrote:
> Add verify-only public key crypto support for ML-DSA so that the
> X.509/PKCS#7 signature verification code, as used by module signing,
> amongst other things, can make use of it through the common crypto_sig API.
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Eric Biggers <ebiggers@kernel.org>
> cc: Lukas Wunner <lukas@wunner.de>
> cc: Ignat Korchagin <ignat@cloudflare.com>
> cc: Stephan Mueller <smueller@chronox.de>
> cc: Herbert Xu <herbert@gondor.apana.org.au>
> cc: keyrings@vger.kernel.org
> cc: linux-crypto@vger.kernel.org
> ---
> crypto/Kconfig | 10 +++
> crypto/Makefile | 2 +
> crypto/mldsa.c | 201 ++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 213 insertions(+)
> create mode 100644 crypto/mldsa.c
>
> diff --git a/crypto/Kconfig b/crypto/Kconfig
> index 12a87f7cf150..8dd5c6660c5a 100644
> --- a/crypto/Kconfig
> +++ b/crypto/Kconfig
> @@ -344,6 +344,16 @@ config CRYPTO_ECRDSA
> One of the Russian cryptographic standard algorithms (called GOST
> algorithms). Only signature verification is implemented.
>
> +config CRYPTO_MLDSA
> + tristate "ML-DSA (Module-Lattice-Based Digital Signature Algorithm)"
> + select CRYPTO_SIG
> + select CRYPTO_LIB_MLDSA
> + select CRYPTO_LIB_SHA3
> + help
> + ML-DSA (Module-Lattice-Based Digital Signature Algorithm) (FIPS-204).
> +
> + Only signature verification is implemented.
> +
> endmenu
>
> menu "Block ciphers"
> diff --git a/crypto/Makefile b/crypto/Makefile
> index 23d3db7be425..267d5403045b 100644
> --- a/crypto/Makefile
> +++ b/crypto/Makefile
> @@ -60,6 +60,8 @@ ecdsa_generic-y += ecdsa-p1363.o
> ecdsa_generic-y += ecdsasignature.asn1.o
> obj-$(CONFIG_CRYPTO_ECDSA) += ecdsa_generic.o
>
> +obj-$(CONFIG_CRYPTO_MLDSA) += mldsa.o
> +
> crypto_acompress-y := acompress.o
> crypto_acompress-y += scompress.o
> obj-$(CONFIG_CRYPTO_ACOMP2) += crypto_acompress.o
> diff --git a/crypto/mldsa.c b/crypto/mldsa.c
> new file mode 100644
> index 000000000000..2146c774b5ca
> --- /dev/null
> +++ b/crypto/mldsa.c
> @@ -0,0 +1,201 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * crypto_sig wrapper around ML-DSA library.
> + */
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <crypto/internal/sig.h>
> +#include <crypto/mldsa.h>
> +
> +struct crypto_mldsa_ctx {
> + u8 pk[MAX(MAX(MLDSA44_PUBLIC_KEY_SIZE,
> + MLDSA65_PUBLIC_KEY_SIZE),
> + MLDSA87_PUBLIC_KEY_SIZE)];
> + unsigned int pk_len;
> + enum mldsa_alg strength;
> + u8 key_set;
> +};
> +
> +static int crypto_mldsa_sign(struct crypto_sig *tfm,
> + const void *msg, unsigned int msg_len,
> + void *sig, unsigned int sig_len)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static int crypto_mldsa_verify(struct crypto_sig *tfm,
> + const void *sig, unsigned int sig_len,
> + const void *msg, unsigned int msg_len)
> +{
> + const struct crypto_mldsa_ctx *ctx = crypto_sig_ctx(tfm);
> +
> + if (unlikely(!ctx->key_set))
> + return -EINVAL;
> +
> + return mldsa_verify(ctx->strength, sig, sig_len, msg, msg_len,
> + ctx->pk, ctx->pk_len);
> +}
> +
> +static unsigned int crypto_mldsa_key_size(struct crypto_sig *tfm)
> +{
> + struct crypto_mldsa_ctx *ctx = crypto_sig_ctx(tfm);
> +
> + switch (ctx->strength) {
> + case MLDSA44:
> + return MLDSA44_PUBLIC_KEY_SIZE;
> + case MLDSA65:
> + return MLDSA65_PUBLIC_KEY_SIZE;
> + case MLDSA87:
> + return MLDSA87_PUBLIC_KEY_SIZE;
> + default:
> + WARN_ON_ONCE(1);
> + return 0;
> + }
> +}
> +
> +static int crypto_mldsa_set_pub_key(struct crypto_sig *tfm,
> + const void *key, unsigned int keylen)
> +{
> + struct crypto_mldsa_ctx *ctx = crypto_sig_ctx(tfm);
> + unsigned int expected_len = crypto_mldsa_key_size(tfm);
> +
> + if (keylen != expected_len)
> + return -EINVAL;
> +
> + ctx->pk_len = keylen;
> + memcpy(ctx->pk, key, keylen);
> + ctx->key_set = true;
> + return 0;
> +}
> +
> +static int crypto_mldsa_set_priv_key(struct crypto_sig *tfm,
> + const void *key, unsigned int keylen)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static unsigned int crypto_mldsa_max_size(struct crypto_sig *tfm)
> +{
> + struct crypto_mldsa_ctx *ctx = crypto_sig_ctx(tfm);
> +
> + switch (ctx->strength) {
> + case MLDSA44:
> + return MLDSA44_SIGNATURE_SIZE;
> + case MLDSA65:
> + return MLDSA65_SIGNATURE_SIZE;
> + case MLDSA87:
> + return MLDSA87_SIGNATURE_SIZE;
> + default:
> + WARN_ON_ONCE(1);
> + return 0;
> + }
> +}
> +
> +static int crypto_mldsa44_alg_init(struct crypto_sig *tfm)
> +{
> + struct crypto_mldsa_ctx *ctx = crypto_sig_ctx(tfm);
> +
> + ctx->strength = MLDSA44;
> + ctx->key_set = false;
> + return 0;
> +}
> +
> +static int crypto_mldsa65_alg_init(struct crypto_sig *tfm)
> +{
> + struct crypto_mldsa_ctx *ctx = crypto_sig_ctx(tfm);
> +
> + ctx->strength = MLDSA65;
> + ctx->key_set = false;
> + return 0;
> +}
> +
> +static int crypto_mldsa87_alg_init(struct crypto_sig *tfm)
> +{
> + struct crypto_mldsa_ctx *ctx = crypto_sig_ctx(tfm);
> +
> + ctx->strength = MLDSA87;
> + ctx->key_set = false;
> + return 0;
> +}
> +
> +static void crypto_mldsa_alg_exit(struct crypto_sig *tfm)
> +{
> +}
> +
> +static struct sig_alg crypto_mldsa_algs[] = {
> + {
> + .sign = crypto_mldsa_sign,
> + .verify = crypto_mldsa_verify,
> + .set_pub_key = crypto_mldsa_set_pub_key,
> + .set_priv_key = crypto_mldsa_set_priv_key,
> + .key_size = crypto_mldsa_key_size,
> + .max_size = crypto_mldsa_max_size,
> + .init = crypto_mldsa44_alg_init,
> + .exit = crypto_mldsa_alg_exit,
> + .base.cra_name = "mldsa44",
> + .base.cra_driver_name = "mldsa44-lib",
> + .base.cra_ctxsize = sizeof(struct crypto_mldsa_ctx),
> + .base.cra_module = THIS_MODULE,
> + .base.cra_priority = 5000,
> + }, {
> + .sign = crypto_mldsa_sign,
> + .verify = crypto_mldsa_verify,
> + .set_pub_key = crypto_mldsa_set_pub_key,
> + .set_priv_key = crypto_mldsa_set_priv_key,
> + .key_size = crypto_mldsa_key_size,
> + .max_size = crypto_mldsa_max_size,
> + .init = crypto_mldsa65_alg_init,
> + .exit = crypto_mldsa_alg_exit,
> + .base.cra_name = "mldsa65",
> + .base.cra_driver_name = "mldsa65-lib",
> + .base.cra_ctxsize = sizeof(struct crypto_mldsa_ctx),
> + .base.cra_module = THIS_MODULE,
> + .base.cra_priority = 5000,
> + }, {
> + .sign = crypto_mldsa_sign,
> + .verify = crypto_mldsa_verify,
> + .set_pub_key = crypto_mldsa_set_pub_key,
> + .set_priv_key = crypto_mldsa_set_priv_key,
> + .key_size = crypto_mldsa_key_size,
> + .max_size = crypto_mldsa_max_size,
> + .init = crypto_mldsa87_alg_init,
> + .exit = crypto_mldsa_alg_exit,
> + .base.cra_name = "mldsa87",
> + .base.cra_driver_name = "mldsa87-lib",
> + .base.cra_ctxsize = sizeof(struct crypto_mldsa_ctx),
> + .base.cra_module = THIS_MODULE,
> + .base.cra_priority = 5000,
> + },
> +};
> +
> +static int __init mldsa_init(void)
> +{
> + int ret, i;
> +
> + for (i = 0; i < ARRAY_SIZE(crypto_mldsa_algs); i++) {
> + ret = crypto_register_sig(&crypto_mldsa_algs[i]);
> + if (ret < 0)
> + goto error;
> + }
> + return 0;
> +
> +error:
> + pr_err("Failed to register (%d)\n", ret);
> + for (i--; i >= 0; i--)
> + crypto_unregister_sig(&crypto_mldsa_algs[i]);
> + return ret;
> +}
> +module_init(mldsa_init);
> +
> +static void mldsa_exit(void)
> +{
> + for (int i = 0; i < ARRAY_SIZE(crypto_mldsa_algs); i++)
> + crypto_unregister_sig(&crypto_mldsa_algs[i]);
> +}
> +module_exit(mldsa_exit);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Crypto API support for ML-DSA signature verification");
> +MODULE_ALIAS_CRYPTO("mldsa44");
> +MODULE_ALIAS_CRYPTO("mldsa65");
> +MODULE_ALIAS_CRYPTO("mldsa87");
>

Went through it, not much else to say, as it just binds the callbacks:

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko