feat(lib/psa): add initial attestation API

Supports:
 - Get Platform Attestation token from secure enclave

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: Icaeb7b4eaff08e10f449fbf752068de3ac7974bf

include/lib/psa/initial_attestation.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2018-2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#ifndef PSA_INITIAL_ATTESTATION_H
+#define PSA_INITIAL_ATTESTATION_H
+
+#include <limits.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "psa/error.h"
+
+/*
+ * Initial attestation API version is: 1.0.0
+ */
+#define PSA_INITIAL_ATTEST_API_VERSION_MAJOR	(1)
+#define PSA_INITIAL_ATTEST_API_VERSION_MINOR	(0)
+
+/* The allowed size of input challenge in bytes. */
+#define PSA_INITIAL_ATTEST_CHALLENGE_SIZE_32	32U
+#define PSA_INITIAL_ATTEST_CHALLENGE_SIZE_48	48U
+#define PSA_INITIAL_ATTEST_CHALLENGE_SIZE_64	64U
+
+/* Initial Attestation message types that distinguish Attest services. */
+#define RSS_ATTEST_GET_TOKEN		1001U
+#define RSS_ATTEST_GET_TOKEN_SIZE	1002U
+#define RSS_ATTEST_GET_DELEGATED_KEY	1003U
+
+/**
+ * Get the platform attestation token.
+ *
+ * auth_challenge	Pointer to buffer where challenge input is stored. This
+ *			must be the hash of the public part of the delegated
+ *			attestation key.
+ * challenge_size	Size of challenge object in bytes.
+ * token_buf		Pointer to the buffer where attestation token will be
+ *			stored.
+ * token_buf_size	Size of allocated buffer for token, in bytes.
+ * token_size		Size of the token that has been returned, in bytes.
+ *
+ * Returns error code as specified in psa_status_t.
+ */
+psa_status_t
+psa_initial_attest_get_token(const uint8_t *auth_challenge,
+			     size_t         challenge_size,
+			     uint8_t       *token_buf,
+			     size_t         token_buf_size,
+			     size_t        *token_size);
+
+#endif /* PSA_INITIAL_ATTESTATION_H */

lib/psa/initial_attestation.c

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2018-2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include <initial_attestation.h>
+#include <psa/client.h>
+#include <psa_manifest/sid.h>
+
+psa_status_t
+psa_initial_attest_get_token(const uint8_t *auth_challenge,
+			     size_t         challenge_size,
+			     uint8_t       *token_buf,
+			     size_t         token_buf_size,
+			     size_t        *token_size)
+{
+	psa_status_t status;
+	psa_invec in_vec[] = {
+		{auth_challenge, challenge_size}
+	};
+	psa_outvec out_vec[] = {
+		{token_buf, token_buf_size},
+	};
+
+	status = psa_call(RSS_ATTESTATION_SERVICE_HANDLE, RSS_ATTEST_GET_TOKEN,
+			  in_vec, IOVEC_LEN(in_vec),
+			  out_vec, IOVEC_LEN(out_vec));
+
+	if (status == PSA_SUCCESS) {
+		*token_size = out_vec[0].len;
+	}
+
+	return status;
+}