psa: Add get/set domain parameters

DSA and static DH need extra domain parameters. Instead of passing these
in with the keys themselves, add get and set functions to set and
retrieve this information about keys.

Author: Patater

include/psa/crypto.h

@@ -369,6 +369,72 @@ psa_status_t psa_get_key_information(psa_key_handle_t handle,
                                      psa_key_type_t *type,
                                      size_t *bits);
 
+/**
+ * \brief Set domain parameters for a key.
+ *
+ * Some key types require additional domain parameters to be set before import
+ * or generation of the key. The domain parameters can be set with this
+ * function or, for key generation, through the \c extra parameter of
+ * psa_generate_key().
+ *
+ * The format for the required domain parameters varies by the key type.
+ *
+ * \param handle      Handle to the key to set domain parameters for.
+ * \param[in] data    Buffer containing the key domain parameters. The content
+ *                    of this buffer is interpreted according to \p type. of
+ *                    psa_export_key() or psa_export_public_key() for the
+ *                    chosen type.
+ * \param data_length Size of the \p data buffer in bytes.
+ *
+ * \retval #PSA_SUCCESS
+ * \retval #PSA_ERROR_INVALID_HANDLE
+ * \retval #PSA_ERROR_OCCUPIED_SLOT
+ *         There is already a key in the specified slot.
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ * \retval #PSA_ERROR_COMMUNICATION_FAILURE
+ * \retval #PSA_ERROR_HARDWARE_FAILURE
+ * \retval #PSA_ERROR_TAMPERING_DETECTED
+ * \retval #PSA_ERROR_BAD_STATE
+ *         The library has not been previously initialized by psa_crypto_init().
+ *         It is implementation-dependent whether a failure to initialize
+ *         results in this error code.
+ */
+psa_status_t psa_set_key_domain_parameters(psa_key_handle_t handle,
+                                           const uint8_t *data,
+                                           size_t data_length);
+
+/**
+ * \brief Get domain parameters for a key.
+ *
+ * Get the domain parameters for a key with this function, if any. The format
+ * of the domain parameters written to \p data is specified in the
+ * documentation for psa_set_key_domain_parameters().
+ *
+ * \param handle            Handle to the key to get domain parameters from.
+ * \param[out] data         On success, the key domain parameters.
+ * \param data_size         Size of the \p data buffer in bytes.
+ * \param[out] data_length  On success, the number of bytes
+ *                          that make up the key domain parameters data.
+ *
+ * \retval #PSA_SUCCESS
+ * \retval #PSA_ERROR_INVALID_HANDLE
+ * \retval #PSA_ERROR_EMPTY_SLOT
+ *         There is no key in the specified slot.
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ * \retval #PSA_ERROR_NOT_SUPPORTED
+ * \retval #PSA_ERROR_COMMUNICATION_FAILURE
+ * \retval #PSA_ERROR_HARDWARE_FAILURE
+ * \retval #PSA_ERROR_TAMPERING_DETECTED
+ * \retval #PSA_ERROR_BAD_STATE
+ *         The library has not been previously initialized by psa_crypto_init().
+ *         It is implementation-dependent whether a failure to initialize
+ *         results in this error code.
+ */
+psa_status_t psa_get_key_domain_parameters(psa_key_handle_t handle,
+                                           uint8_t *data,
+                                           size_t data_size,
+                                           size_t *data_length);
+
 /**
  * \brief Export a key in binary format.
  *

library/psa_crypto.c

@@ -738,7 +738,7 @@ psa_status_t psa_import_key_into_slot( psa_key_slot_t *slot,
 }
 
 /* Retrieve an empty key slot (slot with no key data, but possibly
- * with some metadata such as a policy). */
+ * with some metadata such as a policy or domain parameters). */
 static psa_status_t psa_get_empty_key_slot( psa_key_handle_t handle,
                                             psa_key_slot_t **p_slot )
 {