Read and write X25519 and X448 private keys
Signed-off-by: Jethro Beekman <jethro@fortanix.com>
Co-authored-by: Gijs Kwakkel <gijs.kwakkel@fortanix.com>
Signed-off-by: Gijs Kwakkel <gijs.kwakkel@fortanix.com>
diff --git a/library/pkwrite.c b/library/pkwrite.c
index 3c1a408..c753aa9 100644
--- a/library/pkwrite.c
+++ b/library/pkwrite.c
@@ -213,7 +213,8 @@
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *c;
- size_t len = 0, par_len = 0, oid_len;
+ int has_par = 1;
+ size_t len = 0, par_len = 0, oid_len = 0;
mbedtls_pk_type_t pk_type;
const char *oid;
@@ -243,7 +244,17 @@
pk_type = mbedtls_pk_get_type(key);
#if defined(MBEDTLS_ECP_LIGHT)
if (pk_type == MBEDTLS_PK_ECKEY) {
- MBEDTLS_ASN1_CHK_ADD(par_len, pk_write_ec_param(&c, buf, mbedtls_pk_ec(*key)));
+ mbedtls_ecp_keypair *ec = mbedtls_pk_ec(*key);
+
+ ret = mbedtls_oid_get_oid_by_ec_grp_algid(ec->grp.id, &oid, &oid_len);
+
+ if (ret == 0) {
+ has_par = 0;
+ } else if (ret == MBEDTLS_ERR_OID_NOT_FOUND) {
+ MBEDTLS_ASN1_CHK_ADD(par_len, pk_write_ec_param(&c, buf, ec));
+ } else {
+ return ret;
+ }
}
#endif /* MBEDTLS_ECP_LIGHT */
#if defined(MBEDTLS_USE_PSA_CRYPTO)
@@ -253,6 +264,8 @@
mbedtls_svc_key_id_t key_id;
psa_ecc_family_t curve;
size_t bits;
+ size_t oid2_len = 0;
+ const char *oid2;
key_id = *((mbedtls_svc_key_id_t *) key->pk_ctx);
if (PSA_SUCCESS != psa_get_key_attributes(key_id, &attributes)) {
@@ -269,7 +282,7 @@
}
ret = mbedtls_psa_get_ecc_oid_from_id(curve, bits,
- &oid, &oid_len);
+ &oid2, &oid2_len);
if (ret != 0) {
return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
}
@@ -277,8 +290,8 @@
/* Write EC algorithm parameters; that's akin
* to pk_write_ec_param() above. */
MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_oid(&c, buf,
- oid,
- oid_len));
+ oid2,
+ oid2_len));
/* The rest of the function works as for legacy EC contexts. */
pk_type = MBEDTLS_PK_ECKEY;
@@ -291,13 +304,15 @@
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
- if ((ret = mbedtls_oid_get_oid_by_pk_alg(pk_type, &oid,
- &oid_len)) != 0) {
- return ret;
+ if (oid_len == 0) {
+ if ((ret = mbedtls_oid_get_oid_by_pk_alg(pk_type, &oid,
+ &oid_len)) != 0) {
+ return ret;
+ }
}
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_algorithm_identifier(&c, buf, oid, oid_len,
- par_len));
+ MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_algorithm_identifier_ext(&c, buf, oid, oid_len,
+ par_len, has_par));
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONSTRUCTED |
@@ -306,6 +321,55 @@
return (int) len;
}
+#if defined(MBEDTLS_ECP_LIGHT)
+#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
+/*
+ * RFC8410
+ *
+ * OneAsymmetricKey ::= SEQUENCE {
+ * version Version,
+ * privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
+ * privateKey PrivateKey,
+ * attributes [0] IMPLICIT Attributes OPTIONAL,
+ * ...,
+ * [[2: publicKey [1] IMPLICIT PublicKey OPTIONAL ]],
+ * ...
+ * }
+ *
+ * CurvePrivateKey ::= OCTET STRING
+ */
+static int pk_write_ec_rfc8410_der(unsigned char **p, unsigned char *buf,
+ mbedtls_ecp_keypair *ec)
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+ size_t len = 0;
+ size_t oid_len = 0;
+ const char *oid;
+
+ /* privateKey */
+ MBEDTLS_ASN1_CHK_ADD(len, pk_write_ec_private(p, buf, ec));
+ MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, buf, len));
+ MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, buf, MBEDTLS_ASN1_OCTET_STRING));
+
+ /* privateKeyAlgorithm */
+ if ((ret = mbedtls_oid_get_oid_by_ec_grp_algid(ec->grp.id, &oid, &oid_len)) != 0) {
+ return ret;
+ }
+ MBEDTLS_ASN1_CHK_ADD(len,
+ mbedtls_asn1_write_algorithm_identifier_ext(p, buf, oid, oid_len, 0, 0));
+
+ /* version */
+ MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(p, buf, 0));
+
+ MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, buf, len));
+ MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, buf, MBEDTLS_ASN1_CONSTRUCTED |
+ MBEDTLS_ASN1_SEQUENCE));
+
+ return (int) len;
+}
+#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
+#endif /* MBEDTLS_ECP_LIGHT */
+
int mbedtls_pk_write_key_der(const mbedtls_pk_context *key, unsigned char *buf, size_t size)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -409,6 +473,12 @@
mbedtls_ecp_keypair *ec = mbedtls_pk_ec(*key);
size_t pub_len = 0, par_len = 0;
+#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
+ if (mbedtls_pk_is_rfc8410_curve(ec->grp.id)) {
+ return pk_write_ec_rfc8410_der(&c, buf, ec);
+ }
+#endif
+
/*
* RFC 5915, or SEC1 Appendix C.4
*
@@ -472,6 +542,8 @@
#define PEM_END_PRIVATE_KEY_RSA "-----END RSA PRIVATE KEY-----\n"
#define PEM_BEGIN_PRIVATE_KEY_EC "-----BEGIN EC PRIVATE KEY-----\n"
#define PEM_END_PRIVATE_KEY_EC "-----END EC PRIVATE KEY-----\n"
+#define PEM_BEGIN_PRIVATE_KEY_PKCS8 "-----BEGIN PRIVATE KEY-----\n"
+#define PEM_END_PRIVATE_KEY_PKCS8 "-----END PRIVATE KEY-----\n"
#define PUB_DER_MAX_BYTES \
(MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES > MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES ? \
@@ -519,8 +591,16 @@
#endif
#if defined(MBEDTLS_ECP_LIGHT)
if (mbedtls_pk_get_type(key) == MBEDTLS_PK_ECKEY) {
- begin = PEM_BEGIN_PRIVATE_KEY_EC;
- end = PEM_END_PRIVATE_KEY_EC;
+#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
+ if (mbedtls_pk_is_rfc8410_curve(mbedtls_pk_ec(*key)->grp.id)) {
+ begin = PEM_BEGIN_PRIVATE_KEY_PKCS8;
+ end = PEM_END_PRIVATE_KEY_PKCS8;
+ } else
+#endif
+ {
+ begin = PEM_BEGIN_PRIVATE_KEY_EC;
+ end = PEM_END_PRIVATE_KEY_EC;
+ }
} else
#endif
return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;