ECC export/import: updated documentation on EdDSA curves

This clarifies the format that parameters in the EdDSA curves
will be returned, and also ensures that the import/export
functions fail on unsupported curves.

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

5 files changed, 36 insertions, 13 deletions

diff --git a/lib/algorithms.h b/lib/algorithms.h
index 46faa8d378..880e6b9c90 100644
--- a/lib/algorithms.h
+++ b/lib/algorithms.h
@@ -426,9 +426,8 @@ gnutls_pk_algorithm_t _gnutls_oid_to_pk_and_curve(const char *oid, gnutls_ecc_cu
 
 inline static int _curve_is_eddsa(const gnutls_ecc_curve_entry_st * e)
 {
-	size_t ret = 0;
 	if (unlikely(e == NULL))
-		return ret;
+		return 0;
 	if (e->pk == GNUTLS_PK_EDDSA_ED25519)
 		return 1;
 	return 0;
diff --git a/lib/pk.c b/lib/pk.c
index c5f5c05ed3..1f137f71cb 100644
--- a/lib/pk.c
+++ b/lib/pk.c
@@ -1014,6 +1014,7 @@ int _gnutls_params_get_ecc_raw(const gnutls_pk_params_st* params,
 {
 	int ret;
 	mpi_dprint_func dprint = _gnutls_mpi_dprint_lz;
+	const gnutls_ecc_curve_entry_st *e;
 
 	if (flags & GNUTLS_EXPORT_FLAG_NO_LZ)
 		dprint = _gnutls_mpi_dprint;
@@ -1026,7 +1027,9 @@ int _gnutls_params_get_ecc_raw(const gnutls_pk_params_st* params,
 	if (curve)
 		*curve = params->curve;
 
-	if (curve_is_eddsa(params->curve)) {
+	e = _gnutls_ecc_curve_get_params(params->curve);
+
+	if (_curve_is_eddsa(e)) {
 		if (x) {
 			ret = _gnutls_set_datum(x, params->raw_pub.data, params->raw_pub.size);
 			if (ret < 0) {
@@ -1050,6 +1053,8 @@ int _gnutls_params_get_ecc_raw(const gnutls_pk_params_st* params,
 		return 0;
 	}
 
+	if (unlikely(e == NULL || e->pk != GNUTLS_PK_ECDSA))
+		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
 
 	/* X */
 	if (x) {
diff --git a/lib/privkey_raw.c b/lib/privkey_raw.c
index c78c6b71f8..4db22d84b4 100644
--- a/lib/privkey_raw.c
+++ b/lib/privkey_raw.c
@@ -199,6 +199,9 @@ int ret;
  * in the given structure. The new parameters will be allocated using
  * gnutls_malloc() and will be stored in the appropriate datum.
  *
+ * In EdDSA curves the @y parameter will be %NULL and the other parameters
+ * will be in the native format for the curve.
+ *
  * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
  *
  * Since: 3.3.0
@@ -226,6 +229,9 @@ gnutls_privkey_export_ecc_raw(gnutls_privkey_t key,
  * in the given structure. The new parameters will be allocated using
  * gnutls_malloc() and will be stored in the appropriate datum.
  *
+ * In EdDSA curves the @y parameter will be %NULL and the other parameters
+ * will be in the native format for the curve.
+ *
  * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
  *
  * Since: 3.6.0
@@ -430,6 +436,9 @@ error:
  * native #gnutls_privkey_t format.  The output will be stored
  * in @key.
  *
+ * In EdDSA curves the @y parameter should be %NULL and the @x parameter must
+ * be the value in the native format for the curve.
+ *
  * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
  *   negative error value.
  *
@@ -437,10 +446,10 @@ error:
  **/
 int
 gnutls_privkey_import_ecc_raw(gnutls_privkey_t key,
-				   gnutls_ecc_curve_t curve,
-				   const gnutls_datum_t * x,
-				   const gnutls_datum_t * y,
-				   const gnutls_datum_t * k)
+			      gnutls_ecc_curve_t curve,
+			      const gnutls_datum_t * x,
+			      const gnutls_datum_t * y,
+			      const gnutls_datum_t * k)
 {
 int ret;
 gnutls_x509_privkey_t xkey;
diff --git a/lib/pubkey.c b/lib/pubkey.c
index 34aea10ad8..8959fe1c10 100644
--- a/lib/pubkey.c
+++ b/lib/pubkey.c
@@ -827,7 +827,9 @@ gnutls_pubkey_export_dsa_raw2(gnutls_pubkey_t key,
  * This function will export the ECC public key's parameters found in
  * the given key.  The new parameters will be allocated using
  * gnutls_malloc() and will be stored in the appropriate datum.
- * For EdDSA public keys, @y will be set to %NULL.
+ *
+ * In EdDSA curves the @y parameter will be %NULL and the other parameters
+ * will be in the native format for the curve.
  *
  * This function allows for %NULL parameters since 3.4.1.
  *
@@ -855,6 +857,9 @@ gnutls_pubkey_export_ecc_raw(gnutls_pubkey_t key,
  * the given key.  The new parameters will be allocated using
  * gnutls_malloc() and will be stored in the appropriate datum.
  *
+ * In EdDSA curves the @y parameter will be %NULL and the other parameters
+ * will be in the native format for the curve.
+ *
  * This function allows for %NULL parameters since 3.4.1.
  *
  * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
@@ -1385,8 +1390,10 @@ gnutls_pubkey_import_rsa_raw(gnutls_pubkey_t key,
  * @y: holds the y
  *
  * This function will convert the given elliptic curve parameters to a
- * #gnutls_pubkey_t.  The output will be stored in @key. For EdDSA
- * keys the @y parameter should be %NULL.
+ * #gnutls_pubkey_t.  The output will be stored in @key.
+ *
+ * In EdDSA curves the @y parameter will be %NULL and the other parameters
+ * will be in the native format for the curve.
  *
  * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
  *   negative error value.
diff --git a/lib/x509/privkey.c b/lib/x509/privkey.c
index c018f6dc97..562ad418d0 100644
--- a/lib/x509/privkey.c
+++ b/lib/x509/privkey.c
@@ -1088,7 +1088,8 @@ gnutls_x509_privkey_import_dsa_raw(gnutls_x509_privkey_t key,
  *
  * This function will convert the given elliptic curve parameters to the
  * native #gnutls_x509_privkey_t format.  The output will be stored
- * in @key. For EdDSA keys, the @x and @k values will be read.
+ * in @key. For EdDSA keys, the @x and @k values must be in the
+ * native to curve format.
  *
  * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
  *   negative error value.
@@ -1530,7 +1531,9 @@ gnutls_sec_param_t gnutls_x509_privkey_sec_param(gnutls_x509_privkey_t key)
  * This function will export the ECC private key's parameters found
  * in the given structure. The new parameters will be allocated using
  * gnutls_malloc() and will be stored in the appropriate datum.
- * For EdDSA keys, the @y value should be %NULL.
+ *
+ * In EdDSA curves the @y parameter will be %NULL and the other parameters
+ * will be in the native format for the curve.
  *
  * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
  *   negative error value.
@@ -1552,7 +1555,7 @@ int gnutls_x509_privkey_export_ecc_raw(gnutls_x509_privkey_t key,
 }
 
 /**
- * gnutls_x509_privkey_export_ecc_raw:
+ * gnutls_x509_privkey_export_gost_raw:
  * @key: a key
  * @curve: will hold the curve
  * @digest: will hold the digest