Re: [PATCH v16 5/7] pkcs7, x509: Add ML-DSA support

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, Feb 02, 2026 at 05:02:10PM +0000, David Howells wrote:
> Add support for ML-DSA keys and signatures to the CMS/PKCS#7 and X.509
> implementations.  ML-DSA-44, -65 and -87 are all supported.  For X.509
> certificates, the TBSCertificate is required to be signed directly; for
> CMS, direct signing of the data is preferred, though use of SHA512 (and
> only that) as an intermediate hash of the content is permitted with
> signedAttrs.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Lukas Wunner <lukas@wunner.de>
> cc: Ignat Korchagin <ignat@cloudflare.com>
> cc: Stephan Mueller <smueller@chronox.de>
> cc: Eric Biggers <ebiggers@kernel.org>
> cc: Herbert Xu <herbert@gondor.apana.org.au>
> cc: keyrings@vger.kernel.org
> cc: linux-crypto@vger.kernel.org
> ---
>  crypto/asymmetric_keys/pkcs7_parser.c     | 24 +++++++++++++++++++-
>  crypto/asymmetric_keys/public_key.c       | 10 +++++++++
>  crypto/asymmetric_keys/x509_cert_parser.c | 27 ++++++++++++++++++++++-
>  include/linux/oid_registry.h              |  5 +++++
>  4 files changed, 64 insertions(+), 2 deletions(-)
> 
> diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c
> index 3cdbab3b9f50..594a8f1d9dfb 100644
> --- a/crypto/asymmetric_keys/pkcs7_parser.c
> +++ b/crypto/asymmetric_keys/pkcs7_parser.c
> @@ -95,11 +95,18 @@ static int pkcs7_check_authattrs(struct pkcs7_message *msg)
>  	if (sinfo->authattrs) {
>  		want = true;
>  		msg->have_authattrs = true;
> +	} else if (sinfo->sig->algo_takes_data) {
> +		sinfo->sig->hash_algo = "none";
>  	}
>  
> -	for (sinfo = sinfo->next; sinfo; sinfo = sinfo->next)
> +	for (sinfo = sinfo->next; sinfo; sinfo = sinfo->next) {
>  		if (!!sinfo->authattrs != want)
>  			goto inconsistent;
> +
> +		if (!sinfo->authattrs &&
> +		    sinfo->sig->algo_takes_data)
> +			sinfo->sig->hash_algo = "none";
> +	}
>  	return 0;
>  
>  inconsistent:
> @@ -297,6 +304,21 @@ int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen,
>  		ctx->sinfo->sig->pkey_algo = "ecrdsa";
>  		ctx->sinfo->sig->encoding = "raw";
>  		break;
> +	case OID_id_ml_dsa_44:
> +		ctx->sinfo->sig->pkey_algo = "mldsa44";
> +		ctx->sinfo->sig->encoding = "raw";
> +		ctx->sinfo->sig->algo_takes_data = true;
> +		break;
> +	case OID_id_ml_dsa_65:
> +		ctx->sinfo->sig->pkey_algo = "mldsa65";
> +		ctx->sinfo->sig->encoding = "raw";
> +		ctx->sinfo->sig->algo_takes_data = true;
> +		break;
> +	case OID_id_ml_dsa_87:
> +		ctx->sinfo->sig->pkey_algo = "mldsa87";
> +		ctx->sinfo->sig->encoding = "raw";
> +		ctx->sinfo->sig->algo_takes_data = true;
> +		break;
>  	default:
>  		printk("Unsupported pkey algo: %u\n", ctx->last_oid);
>  		return -ENOPKG;
> diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
> index a46356e0c08b..09a0b83d5d77 100644
> --- a/crypto/asymmetric_keys/public_key.c
> +++ b/crypto/asymmetric_keys/public_key.c
> @@ -142,6 +142,16 @@ software_key_determine_akcipher(const struct public_key *pkey,
>  		if (strcmp(hash_algo, "streebog256") != 0 &&
>  		    strcmp(hash_algo, "streebog512") != 0)
>  			return -EINVAL;
> +	} else if (strcmp(pkey->pkey_algo, "mldsa44") == 0 ||
> +		   strcmp(pkey->pkey_algo, "mldsa65") == 0 ||
> +		   strcmp(pkey->pkey_algo, "mldsa87") == 0) {
> +		if (strcmp(encoding, "raw") != 0)
> +			return -EINVAL;
> +		if (!hash_algo)
> +			return -EINVAL;
> +		if (strcmp(hash_algo, "none") != 0 &&
> +		    strcmp(hash_algo, "sha512") != 0)
> +			return -EINVAL;
>  	} else {
>  		/* Unknown public key algorithm */
>  		return -ENOPKG;
> diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
> index b37cae914987..2fe094f5caf3 100644
> --- a/crypto/asymmetric_keys/x509_cert_parser.c
> +++ b/crypto/asymmetric_keys/x509_cert_parser.c
> @@ -257,6 +257,15 @@ int x509_note_sig_algo(void *context, size_t hdrlen, unsigned char tag,
>  	case OID_gost2012Signature512:
>  		ctx->cert->sig->hash_algo = "streebog512";
>  		goto ecrdsa;
> +	case OID_id_ml_dsa_44:
> +		ctx->cert->sig->pkey_algo = "mldsa44";
> +		goto ml_dsa;
> +	case OID_id_ml_dsa_65:
> +		ctx->cert->sig->pkey_algo = "mldsa65";
> +		goto ml_dsa;
> +	case OID_id_ml_dsa_87:
> +		ctx->cert->sig->pkey_algo = "mldsa87";
> +		goto ml_dsa;
>  	}
>  
>  rsa_pkcs1:
> @@ -274,6 +283,12 @@ int x509_note_sig_algo(void *context, size_t hdrlen, unsigned char tag,
>  	ctx->cert->sig->encoding = "x962";
>  	ctx->sig_algo = ctx->last_oid;
>  	return 0;
> +ml_dsa:
> +	ctx->cert->sig->algo_takes_data = true;
> +	ctx->cert->sig->hash_algo = "none";
> +	ctx->cert->sig->encoding = "raw";
> +	ctx->sig_algo = ctx->last_oid;
> +	return 0;
>  }
>  
>  /*
> @@ -300,7 +315,8 @@ int x509_note_signature(void *context, size_t hdrlen,
>  
>  	if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 ||
>  	    strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0 ||
> -	    strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0) {
> +	    strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0 ||
> +	    strncmp(ctx->cert->sig->pkey_algo, "mldsa", 5) == 0) {
>  		/* Discard the BIT STRING metadata */
>  		if (vlen < 1 || *(const u8 *)value != 0)
>  			return -EBADMSG;
> @@ -524,6 +540,15 @@ int x509_extract_key_data(void *context, size_t hdrlen,
>  			return -ENOPKG;
>  		}
>  		break;
> +	case OID_id_ml_dsa_44:
> +		ctx->cert->pub->pkey_algo = "mldsa44";
> +		break;
> +	case OID_id_ml_dsa_65:
> +		ctx->cert->pub->pkey_algo = "mldsa65";
> +		break;
> +	case OID_id_ml_dsa_87:
> +		ctx->cert->pub->pkey_algo = "mldsa87";
> +		break;
>  	default:
>  		return -ENOPKG;
>  	}
> diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
> index 6de479ebbe5d..ebce402854de 100644
> --- a/include/linux/oid_registry.h
> +++ b/include/linux/oid_registry.h
> @@ -145,6 +145,11 @@ enum OID {
>  	OID_id_rsassa_pkcs1_v1_5_with_sha3_384, /* 2.16.840.1.101.3.4.3.15 */
>  	OID_id_rsassa_pkcs1_v1_5_with_sha3_512, /* 2.16.840.1.101.3.4.3.16 */
>  
> +	/* NIST FIPS-204 ML-DSA */
> +	OID_id_ml_dsa_44,			/* 2.16.840.1.101.3.4.3.17 */
> +	OID_id_ml_dsa_65,			/* 2.16.840.1.101.3.4.3.18 */
> +	OID_id_ml_dsa_87,			/* 2.16.840.1.101.3.4.3.19 */
> +
>  	OID__NR
>  };
>  
> 

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

BR, Jarkko