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/pkparse.c b/library/pkparse.c
index 800e352..617e4fd 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -32,8 +32,9 @@
#if defined(MBEDTLS_RSA_C)
#include "mbedtls/rsa.h"
#endif
-#if defined(MBEDTLS_ECP_C)
#include "mbedtls/ecp.h"
+#if defined(MBEDTLS_RSA_C) || defined(MBEDTLS_ECP_C)
+#include "pkwrite.h"
#endif
#if defined(MBEDTLS_ECDSA_C)
#include "mbedtls/ecdsa.h"
@@ -232,7 +233,7 @@
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *p = params->p;
- const unsigned char * const end = params->p + params->len;
+ const unsigned char *const end = params->p + params->len;
const unsigned char *end_field, *end_curve;
size_t len;
int ver;
@@ -404,7 +405,6 @@
mbedtls_mpi_get_bit(&grp->G.Y, 0) == mbedtls_mpi_get_bit(&ref.G.Y, 0)) {
break;
}
-
}
cleanup:
@@ -495,6 +495,116 @@
return 0;
}
+#if defined(MBEDTLS_ECP_LIGHT)
+/*
+ * Helper function for deriving a public key from its private counterpart.
+ */
+static int pk_derive_public_key(mbedtls_ecp_keypair *eck,
+ const unsigned char *d, size_t d_len,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
+{
+ int ret;
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+ psa_status_t status, destruction_status;
+ psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
+ size_t curve_bits;
+ psa_ecc_family_t curve = mbedtls_ecc_group_to_psa(eck->grp.id, &curve_bits);
+ /* This buffer is used to store the private key at first and then the
+ * public one (but not at the same time). Therefore we size it for the
+ * latter since it's bigger. */
+ unsigned char key_buf[MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH];
+ size_t key_len;
+ mbedtls_svc_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
+
+ (void) f_rng;
+ (void) p_rng;
+
+ psa_set_key_type(&key_attr, PSA_KEY_TYPE_ECC_KEY_PAIR(curve));
+ psa_set_key_usage_flags(&key_attr, PSA_KEY_USAGE_EXPORT);
+
+ status = psa_import_key(&key_attr, d, d_len, &key_id);
+ ret = psa_pk_status_to_mbedtls(status);
+ if (ret != 0) {
+ return ret;
+ }
+
+ mbedtls_platform_zeroize(key_buf, sizeof(key_buf));
+
+ status = psa_export_public_key(key_id, key_buf, sizeof(key_buf), &key_len);
+ ret = psa_pk_status_to_mbedtls(status);
+ destruction_status = psa_destroy_key(key_id);
+ if (ret != 0) {
+ return ret;
+ } else if (destruction_status != PSA_SUCCESS) {
+ return psa_pk_status_to_mbedtls(destruction_status);
+ }
+
+ ret = mbedtls_ecp_point_read_binary(&eck->grp, &eck->Q, key_buf, key_len);
+#else /* MBEDTLS_USE_PSA_CRYPTO */
+ (void) d;
+ (void) d_len;
+
+ ret = mbedtls_ecp_mul(&eck->grp, &eck->Q, &eck->d, &eck->grp.G, f_rng, p_rng);
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+ return ret;
+}
+
+#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
+
+/*
+ * Load an RFC8410 EC key, which doesn't have any parameters
+ */
+static int pk_use_ecparams_rfc8410(const mbedtls_asn1_buf *params,
+ mbedtls_ecp_group_id grp_id,
+ mbedtls_ecp_group *grp)
+{
+ if (params->tag != 0 || params->len != 0) {
+ return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
+ }
+
+ return mbedtls_ecp_group_load(grp, grp_id);
+}
+
+/*
+ * Parse an RFC 8410 encoded private EC key
+ *
+ * CurvePrivateKey ::= OCTET STRING
+ */
+static int pk_parse_key_rfc8410_der(mbedtls_ecp_keypair *eck,
+ unsigned char *key, size_t keylen, const unsigned char *end,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+ size_t len;
+
+ if ((ret = mbedtls_asn1_get_tag(&key, (key + keylen), &len, MBEDTLS_ASN1_OCTET_STRING)) != 0) {
+ return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
+ }
+
+ if (key + len != end) {
+ return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
+ }
+
+ if ((ret = mbedtls_mpi_read_binary_le(&eck->d, key, len)) != 0) {
+ mbedtls_ecp_keypair_free(eck);
+ return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
+ }
+
+ if ((ret = pk_derive_public_key(eck, key, len, f_rng, p_rng)) != 0) {
+ mbedtls_ecp_keypair_free(eck);
+ return ret;
+ }
+
+ if ((ret = mbedtls_ecp_check_privkey(&eck->grp, &eck->d)) != 0) {
+ mbedtls_ecp_keypair_free(eck);
+ return ret;
+ }
+
+ return 0;
+}
+#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
+#endif /* MBEDTLS_ECP_LIGHT */
+
/*
* EC public key is an EC point
*
@@ -591,7 +701,8 @@
*/
static int pk_get_pk_alg(unsigned char **p,
const unsigned char *end,
- mbedtls_pk_type_t *pk_alg, mbedtls_asn1_buf *params)
+ mbedtls_pk_type_t *pk_alg, mbedtls_asn1_buf *params,
+ mbedtls_ecp_group_id *ec_grp_id)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_asn1_buf alg_oid;
@@ -602,7 +713,18 @@
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_ALG, ret);
}
- if (mbedtls_oid_get_pk_alg(&alg_oid, pk_alg) != 0) {
+ ret = mbedtls_oid_get_pk_alg(&alg_oid, pk_alg);
+#if defined(MBEDTLS_ECP_LIGHT)
+ if (ret == MBEDTLS_ERR_OID_NOT_FOUND) {
+ ret = mbedtls_oid_get_ec_grp_algid(&alg_oid, ec_grp_id);
+ if (ret == 0) {
+ *pk_alg = MBEDTLS_PK_ECKEY;
+ }
+ }
+#else
+ (void) ec_grp_id;
+#endif
+ if (ret != 0) {
return MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;
}
@@ -630,6 +752,7 @@
size_t len;
mbedtls_asn1_buf alg_params;
mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;
+ mbedtls_ecp_group_id ec_grp_id = MBEDTLS_ECP_DP_NONE;
const mbedtls_pk_info_t *pk_info;
if ((ret = mbedtls_asn1_get_tag(p, end, &len,
@@ -639,7 +762,7 @@
end = *p + len;
- if ((ret = pk_get_pk_alg(p, end, &pk_alg, &alg_params)) != 0) {
+ if ((ret = pk_get_pk_alg(p, end, &pk_alg, &alg_params, &ec_grp_id)) != 0) {
return ret;
}
@@ -667,7 +790,14 @@
#endif /* MBEDTLS_RSA_C */
#if defined(MBEDTLS_ECP_LIGHT)
if (pk_alg == MBEDTLS_PK_ECKEY_DH || pk_alg == MBEDTLS_PK_ECKEY) {
- ret = pk_use_ecparams(&alg_params, &mbedtls_pk_ec(*pk)->grp);
+#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
+ if (mbedtls_pk_is_rfc8410_curve(ec_grp_id)) {
+ ret = pk_use_ecparams_rfc8410(&alg_params, ec_grp_id, &mbedtls_pk_ec(*pk)->grp);
+ } else
+#endif
+ {
+ ret = pk_use_ecparams(&alg_params, &mbedtls_pk_ec(*pk)->grp);
+ }
if (ret == 0) {
ret = pk_get_ecpubkey(p, end, mbedtls_pk_ec(*pk));
}
@@ -877,57 +1007,6 @@
#endif /* MBEDTLS_RSA_C */
#if defined(MBEDTLS_ECP_LIGHT)
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
-/*
- * Helper function for deriving a public key from its private counterpart by
- * using PSA functions.
- */
-static int pk_derive_public_key(mbedtls_ecp_group *grp, mbedtls_ecp_point *Q,
- const mbedtls_mpi *d)
-{
- psa_status_t status, destruction_status;
- psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
- size_t curve_bits;
- psa_ecc_family_t curve = mbedtls_ecc_group_to_psa(grp->id, &curve_bits);
- /* This buffer is used to store the private key at first and then the
- * public one (but not at the same time). Therefore we size it for the
- * latter since it's bigger. */
- unsigned char key_buf[MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH];
- size_t key_len = PSA_BITS_TO_BYTES(curve_bits);
- mbedtls_svc_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
- int ret;
-
- psa_set_key_type(&key_attr, PSA_KEY_TYPE_ECC_KEY_PAIR(curve));
- psa_set_key_usage_flags(&key_attr, PSA_KEY_USAGE_EXPORT);
-
- ret = mbedtls_mpi_write_binary(d, key_buf, key_len);
- if (ret != 0) {
- return ret;
- }
-
- status = psa_import_key(&key_attr, key_buf, key_len, &key_id);
- ret = psa_pk_status_to_mbedtls(status);
- if (ret != 0) {
- return ret;
- }
-
- mbedtls_platform_zeroize(key_buf, sizeof(key_buf));
-
- status = psa_export_public_key(key_id, key_buf, sizeof(key_buf), &key_len);
- ret = psa_pk_status_to_mbedtls(status);
- destruction_status = psa_destroy_key(key_id);
- if (ret != 0) {
- return ret;
- } else if (destruction_status != PSA_SUCCESS) {
- return psa_pk_status_to_mbedtls(destruction_status);
- }
-
- ret = mbedtls_ecp_point_read_binary(grp, Q, key_buf, key_len);
-
- return ret;
-}
-#endif /* MBEDTLS_USE_PSA_CRYPTO */
-
/*
* Parse a SEC1 encoded private EC key
*/
@@ -937,9 +1016,10 @@
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
int version, pubkey_done;
- size_t len;
+ size_t len, d_len;
mbedtls_asn1_buf params = { 0, 0, NULL };
unsigned char *p = (unsigned char *) key;
+ unsigned char *d;
unsigned char *end = p + keylen;
unsigned char *end2;
@@ -972,6 +1052,8 @@
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
+ d = p;
+ d_len = len;
if ((ret = mbedtls_mpi_read_binary(&eck->d, p, len)) != 0) {
mbedtls_ecp_keypair_free(eck);
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
@@ -1035,20 +1117,10 @@
}
if (!pubkey_done) {
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
- (void) f_rng;
- (void) p_rng;
- if ((ret = pk_derive_public_key(&eck->grp, &eck->Q, &eck->d)) != 0) {
+ if ((ret = pk_derive_public_key(eck, d, d_len, f_rng, p_rng)) != 0) {
mbedtls_ecp_keypair_free(eck);
return ret;
}
-#else /* MBEDTLS_USE_PSA_CRYPTO */
- if ((ret = mbedtls_ecp_mul(&eck->grp, &eck->Q, &eck->d, &eck->grp.G,
- f_rng, p_rng)) != 0) {
- mbedtls_ecp_keypair_free(eck);
- return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
- }
-#endif /* MBEDTLS_USE_PSA_CRYPTO */
}
if ((ret = mbedtls_ecp_check_privkey(&eck->grp, &eck->d)) != 0) {
@@ -1084,9 +1156,10 @@
unsigned char *p = (unsigned char *) key;
unsigned char *end = p + keylen;
mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;
+ mbedtls_ecp_group_id ec_grp_id = MBEDTLS_ECP_DP_NONE;
const mbedtls_pk_info_t *pk_info;
-#if !defined(MBEDTLS_ECP_C)
+#if !defined(MBEDTLS_ECP_LIGHT)
(void) f_rng;
(void) p_rng;
#endif
@@ -1122,7 +1195,7 @@
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_VERSION, ret);
}
- if ((ret = pk_get_pk_alg(&p, end, &pk_alg, ¶ms)) != 0) {
+ if ((ret = pk_get_pk_alg(&p, end, &pk_alg, ¶ms, &ec_grp_id)) != 0) {
return ret;
}
@@ -1153,10 +1226,24 @@
#endif /* MBEDTLS_RSA_C */
#if defined(MBEDTLS_ECP_LIGHT)
if (pk_alg == MBEDTLS_PK_ECKEY || pk_alg == MBEDTLS_PK_ECKEY_DH) {
- if ((ret = pk_use_ecparams(¶ms, &mbedtls_pk_ec(*pk)->grp)) != 0 ||
- (ret = pk_parse_key_sec1_der(mbedtls_pk_ec(*pk), p, len, f_rng, p_rng)) != 0) {
- mbedtls_pk_free(pk);
- return ret;
+#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
+ if (mbedtls_pk_is_rfc8410_curve(ec_grp_id)) {
+ if ((ret =
+ pk_use_ecparams_rfc8410(¶ms, ec_grp_id, &mbedtls_pk_ec(*pk)->grp)) != 0 ||
+ (ret =
+ pk_parse_key_rfc8410_der(mbedtls_pk_ec(*pk), p, len, end, f_rng,
+ p_rng)) != 0) {
+ mbedtls_pk_free(pk);
+ return ret;
+ }
+ } else
+#endif
+ {
+ if ((ret = pk_use_ecparams(¶ms, &mbedtls_pk_ec(*pk)->grp)) != 0 ||
+ (ret = pk_parse_key_sec1_der(mbedtls_pk_ec(*pk), p, len, f_rng, p_rng)) != 0) {
+ mbedtls_pk_free(pk);
+ return ret;
+ }
}
} else
#endif /* MBEDTLS_ECP_LIGHT */
@@ -1557,7 +1644,7 @@
*/
p = pem.buf;
- ret = mbedtls_pk_parse_subpubkey(&p, p + pem.buflen, ctx);
+ ret = mbedtls_pk_parse_subpubkey(&p, p + pem.buflen, ctx);
mbedtls_pem_free(&pem);
return ret;
} else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {