[PATCH v7 3/4] x509: Add support for parsing x509 certs with ECDSA keys

[Stefan Berger]

This patch adds support for parsing of x509 certificates that contain
ECDSA keys, such as NIST P256, that have been signed by a CA using any
of the current SHA hash algorithms.

Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: keyrings@xxxxxxxxxxxxxxx
---
 crypto/asymmetric_keys/public_key.c       | 19 ++++++++++++++
 crypto/asymmetric_keys/x509_cert_parser.c | 32 ++++++++++++++++++++++-
 include/linux/oid_registry.h              |  2 ++
 3 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index 8892908ad58c..7dae61b79d5a 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/seq_file.h>
 #include <linux/scatterlist.h>
+#include <linux/asn1.h>
 #include <keys/asymmetric-subtype.h>
 #include <crypto/public_key.h>
 #include <crypto/akcipher.h>
@@ -90,6 +91,24 @@ int software_key_determine_akcipher(const char *encoding,
 		return 0;
 	}
 
+	if (strcmp(encoding, "x962") == 0) {
+		enum OID oid;
+
+		if (parse_OID(pkey->params, pkey->paramlen, &oid) != 0)
+			return -EBADMSG;
+
+		switch (oid) {
+		case OID_id_prime192v1:
+			strcpy(alg_name, "ecdsa-nist-p192");
+			return 0;
+		case OID_id_prime256v1:
+			strcpy(alg_name, "ecdsa-nist-p256");
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	}
+
 	return -ENOPKG;
 }
 
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 1621ceaf5c95..0aff4e584b11 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -227,6 +227,26 @@ int x509_note_pkey_algo(void *context, size_t hdrlen,
 		ctx->cert->sig->hash_algo = "sha224";
 		goto rsa_pkcs1;
 
+	case OID_id_ecdsa_with_sha1:
+		ctx->cert->sig->hash_algo = "sha1";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha224:
+		ctx->cert->sig->hash_algo = "sha224";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha256:
+		ctx->cert->sig->hash_algo = "sha256";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha384:
+		ctx->cert->sig->hash_algo = "sha384";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha512:
+		ctx->cert->sig->hash_algo = "sha512";
+		goto ecdsa;
+
 	case OID_gost2012Signature256:
 		ctx->cert->sig->hash_algo = "streebog256";
 		goto ecrdsa;
@@ -255,6 +275,11 @@ int x509_note_pkey_algo(void *context, size_t hdrlen,
 	ctx->cert->sig->encoding = "raw";
 	ctx->algo_oid = ctx->last_oid;
 	return 0;
+ecdsa:
+	ctx->cert->sig->pkey_algo = "ecdsa";
+	ctx->cert->sig->encoding = "x962";
+	ctx->algo_oid = ctx->last_oid;
+	return 0;
 }
 
 /*
@@ -276,7 +301,8 @@ 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, "sm2") == 0) {
+	    strcmp(ctx->cert->sig->pkey_algo, "sm2") == 0 ||
+	    strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0) {
 		/* Discard the BIT STRING metadata */
 		if (vlen < 1 || *(const u8 *)value != 0)
 			return -EBADMSG;
@@ -478,6 +504,10 @@ int x509_extract_key_data(void *context, size_t hdrlen,
 		case OID_sm2:
 			ctx->cert->pub->pkey_algo = "sm2";
 			break;
+		case OID_id_prime192v1:
+		case OID_id_prime256v1:
+			ctx->cert->pub->pkey_algo = "ecdsa";
+			break;
 		default:
 			return -ENOPKG;
 		}
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index f3b2c097c886..ff3cad9f8c1f 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h
@@ -21,6 +21,8 @@ enum OID {
 	OID_id_dsa,			/* 1.2.840.10040.4.1 */
 	OID_id_ecdsa_with_sha1,		/* 1.2.840.10045.4.1 */
 	OID_id_ecPublicKey,		/* 1.2.840.10045.2.1 */
+	OID_id_prime192v1,		/* 1.2.840.10045.3.1.1 */
+	OID_id_prime256v1,		/* 1.2.840.10045.3.1.7 */
 	OID_id_ecdsa_with_sha224,	/* 1.2.840.10045.4.3.1 */
 	OID_id_ecdsa_with_sha256,	/* 1.2.840.10045.4.3.2 */
 	OID_id_ecdsa_with_sha384,	/* 1.2.840.10045.4.3.3 */
-- 
2.29.2