[PATCH v9 3/9] x509: Add support for parsing x509 certs with ECDSA keys

[Stefan Berger]

From: Stefan Berger <stefanb@xxxxxxxxxxxxx>

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.

Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: keyrings@xxxxxxxxxxxxxxx
Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>

---

v7->v8:
 - do not detect key algo using parse_OID() in public_key.c but set
   pkey_algo to the key type 'ecdsa-nist-p192/256' when parsing cert
---
 crypto/asymmetric_keys/public_key.c       |  4 ++-
 crypto/asymmetric_keys/x509_cert_parser.c | 34 ++++++++++++++++++++++-
 crypto/asymmetric_keys/x509_public_key.c  |  4 ++-
 include/linux/oid_registry.h              |  2 ++
 4 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index 788a4ba1e2e7..4fefb219bfdc 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>
@@ -85,7 +86,8 @@ int software_key_determine_akcipher(const char *encoding,
 		return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
 	}
 
-	if (strcmp(encoding, "raw") == 0) {
+	if (strcmp(encoding, "raw") == 0 ||
+	    strcmp(encoding, "x962") == 0) {
 		strcpy(alg_name, pkey->pkey_algo);
 		return 0;
 	}
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 1621ceaf5c95..f5d547c6dfb5 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 +504,12 @@ int x509_extract_key_data(void *context, size_t hdrlen,
 		case OID_sm2:
 			ctx->cert->pub->pkey_algo = "sm2";
 			break;
+		case OID_id_prime192v1:
+			ctx->cert->pub->pkey_algo = "ecdsa-nist-p192";
+			break;
+		case OID_id_prime256v1:
+			ctx->cert->pub->pkey_algo = "ecdsa-nist-p256";
+			break;
 		default:
 			return -ENOPKG;
 		}
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index ae450eb8be14..3d45161b271a 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -129,7 +129,9 @@ int x509_check_for_self_signed(struct x509_certificate *cert)
 	}
 
 	ret = -EKEYREJECTED;
-	if (strcmp(cert->pub->pkey_algo, cert->sig->pkey_algo) != 0)
+	if (strcmp(cert->pub->pkey_algo, cert->sig->pkey_algo) != 0 &&
+	    (strncmp(cert->pub->pkey_algo, "ecdsa-", 6) != 0 ||
+	     strcmp(cert->sig->pkey_algo, "ecdsa") != 0))
 		goto out;
 
 	ret = public_key_verify_signature(cert->pub, cert->sig);
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index f32d91895e4d..3583908cf1ca 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h
@@ -20,6 +20,8 @@ enum OID {
 	OID_id_dsa_with_sha1,		/* 1.2.840.10030.4.3 */
 	OID_id_dsa,			/* 1.2.840.10040.4.1 */
 	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_sha1,		/* 1.2.840.10045.4.1 */
 	OID_id_ecdsa_with_sha224,	/* 1.2.840.10045.4.3.1 */
 	OID_id_ecdsa_with_sha256,	/* 1.2.840.10045.4.3.2 */
-- 
2.29.2