pkcs7: Allow authenticatedAttributes for ML-DSA

Allow the rejection of authenticatedAttributes in PKCS#7 (signedAttrs in
CMS) to be waived in the kernel config for ML-DSA when used for module
signing.  This reflects the issue that openssl < 4.0 cannot do this and
openssl-4 has not yet been released.

This does not permit RSA, ECDSA or ECRDSA to be so waived (behaviour
unchanged).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Lukas Wunner <lukas@wunner.de>
cc: Ignat Korchagin <ignat@cloudflare.com>
cc: Jarkko Sakkinen <jarkko@kernel.org>
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

diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig
index e1345b8f39f132ef532bf9418c2718b5a04197ea..1dae2232fe9aea8daec333f20eb783c6f8d65b00 100644 (file)
--- a/crypto/asymmetric_keys/Kconfig
+++ b/crypto/asymmetric_keys/Kconfig
@@ -53,6 +53,17 @@ config PKCS7_MESSAGE_PARSER
          This option provides support for parsing PKCS#7 format messages for
          signature data and provides the ability to verify the signature.
 
+config PKCS7_WAIVE_AUTHATTRS_REJECTION_FOR_MLDSA
+       bool "Waive rejection of authenticatedAttributes for ML-DSA"
+       depends on PKCS7_MESSAGE_PARSER
+       depends on CRYPTO_MLDSA
+       help
+         Due to use of CMS_NOATTR with ML-DSA not being supported in
+         OpenSSL < 4.0 (and thus any released version), enabling this
+         allows authenticatedAttributes to be used with ML-DSA for
+         module signing.  Use of authenticatedAttributes in this
+         context is normally rejected.
+
 config PKCS7_TEST_KEY
        tristate "PKCS#7 testing key type"
        depends on SYSTEM_DATA_VERIFICATION

diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c
index 594a8f1d9dfbded1c9ab8affd81fff2af9b26a66..db1c90ca6fc1582955039946e0bed1f94654afcd 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -92,9 +92,17 @@ static int pkcs7_check_authattrs(struct pkcs7_message *msg)
        if (!sinfo)
                goto inconsistent;
 
+#ifdef CONFIG_PKCS7_WAIVE_AUTHATTRS_REJECTION_FOR_MLDSA
+       msg->authattrs_rej_waivable = true;
+#endif
+
        if (sinfo->authattrs) {
                want = true;
                msg->have_authattrs = true;
+#ifdef CONFIG_PKCS7_WAIVE_AUTHATTRS_REJECTION_FOR_MLDSA
+               if (strncmp(sinfo->sig->pkey_algo, "mldsa", 5) != 0)
+                       msg->authattrs_rej_waivable = false;
+#endif
        } else if (sinfo->sig->algo_takes_data) {
                sinfo->sig->hash_algo = "none";
        }

diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h
index e17f7ce4fb434832a3867ce2254de6ccc7f06ae7..6ef9f335bb17f9ed3fc12e503ee73887fa301aa5 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_parser.h
+++ b/crypto/asymmetric_keys/pkcs7_parser.h
@@ -55,6 +55,9 @@ struct pkcs7_message {
        struct pkcs7_signed_info *signed_infos;
        u8              version;        /* Version of cert (1 -> PKCS#7 or CMS; 3 -> CMS) */
        bool            have_authattrs; /* T if have authattrs */
+#ifdef CONFIG_PKCS7_WAIVE_AUTHATTRS_REJECTION_FOR_MLDSA
+       bool            authattrs_rej_waivable; /* T if authatts rejection can be waived */
+#endif
 
        /* Content Data (or NULL) */
        enum OID        data_type;      /* Type of Data */

diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index 06abb9838f957473162d8a8370b493b66ee0ab13..519eecfe67784a99997f4cc934b407e5f8975cdd 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -425,6 +425,12 @@ int pkcs7_verify(struct pkcs7_message *pkcs7,
                        return -EKEYREJECTED;
                }
                if (pkcs7->have_authattrs) {
+#ifdef CONFIG_PKCS7_WAIVE_AUTHATTRS_REJECTION_FOR_MLDSA
+                       if (pkcs7->authattrs_rej_waivable) {
+                               pr_warn("Waived invalid module sig (has authattrs)\n");
+                               break;
+                       }
+#endif
                        pr_warn("Invalid module sig (has authattrs)\n");
                        return -EKEYREJECTED;
                }