feat(psa): add delegated attestation partition API
Delegated attestation is a service provided by RSS to:
- Derive a delegated attestation key: Realm Attestation Key
- Query the platform attestation token
Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: I3edf09fcbef24bca7c8a000ffac8c1ab64dfb812
diff --git a/include/lib/psa/delegated_attestation.h b/include/lib/psa/delegated_attestation.h
new file mode 100644
index 0000000..7aaceb3
--- /dev/null
+++ b/include/lib/psa/delegated_attestation.h
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+/* This file describes the Delegated Attestation API */
+
+#ifndef DELEGATED_ATTESTATION_H
+#define DELEGATED_ATTESTATION_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "psa/error.h"
+
+/* RSS Delegated Attestation message types that distinguish its services. */
+#define RSS_DELEGATED_ATTEST_GET_DELEGATED_KEY 1001U
+#define RSS_DELEGATED_ATTEST_GET_PLATFORM_TOKEN 1002U
+
+/**
+ * The aim of these APIs to get a derived signing key (private only) for the
+ * delegated attestation model and obtain the corresponding platform attestation
+ * token. In the delegated attestation model the final token consist of more
+ * than one subtokens which are signed by different entities. There is a
+ * cryptographical binding between the tokens. The derived delegated attestation
+ * key is bind to the platform token (details below).
+ *
+ * Expected usage model:
+ * - First rss_delegated_attest_get_delegated_key() API need to be called to
+ * obtain the private part of the delegated attestation key. The public part
+ * of key is computed by the cryptographic library when the key is
+ * registered.
+ * - Secondly the rss_delegated_attest_get_token() must be called to obtain
+ * platform attestation token. The hash of the public key (computed by
+ * the hash_algo indicated in the rss_delegated_attest_get_delegated_key()
+ * call) must be the input of this call. This ensures that nothing but the
+ * previously derived delegated key is bindable to the platform token.
+ */
+
+/**
+ * Get a delegated attestation key (DAK).
+ *
+ * The aim of the delegated attestation key is to enable other SW components
+ * within the system to sign an attestation token which is different than the
+ * initial/platform token. The initial attestation token MUST contain the hash
+ * of the public delegated key to make a cryptographical binding (hash lock)
+ * between the key and the token.
+ * The initial attestation token has two roles in this scenario:
+ * - Attest the device boot status and security lifecycle.
+ * - Attest the delegated attestation key.
+ * The delegated attestation key is derived from a preprovisioned seed. The
+ * input for the key derivation is the platform boot status. The system can be
+ * attestated with the two tokens together.
+ *
+ * ecc_curve The type of the elliptic curve to which the requested
+ * attestation key belongs. Please check the note section for
+ * limitations.
+ * key_bits The size of the requested attestation key, in bits.
+ * key_buf Pointer to the buffer where the delegated attestation key will
+ * be stored.
+ * key_buf_size Size of allocated buffer for the key, in bytes.
+ * key_size Size of the key that has been returned, in bytes.
+ * hash_algo The hash algorithm that will be used later by the owner of the
+ * requested delegated key for binding it to the platform
+ * attestation token.
+ *
+ * Returns error code as specified in psa_status_t.
+ *
+ * Notes:
+ * - Currently, only the PSA_ECC_FAMILY_SECP_R1 curve type is supported.
+ * - The delegated attestation key must be derived before requesting for the
+ * platform attestation token as they are cryptographically linked together.
+ */
+psa_status_t
+rss_delegated_attest_get_delegated_key(uint8_t ecc_curve,
+ uint32_t key_bits,
+ uint8_t *key_buf,
+ size_t key_buf_size,
+ size_t *key_size,
+ uint32_t hash_algo);
+
+/**
+ * Get platform attestation token
+ *
+ * dak_pub_hash Pointer to buffer where the hash of the public DAK is
+ * stored.
+ * dak_pub_hash_size Size of the hash value, in bytes.
+ * token_buf Pointer to the buffer where the platform 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.
+ *
+ * A delegated attestation key must be derived before requesting for the
+ * platform attestation token as they are cryptographically linked together.
+ * Otherwise, the token request will fail and the PSA_ERROR_INVALID_ARGUMENT
+ * code will be returned.
+ */
+psa_status_t
+rss_delegated_attest_get_token(const uint8_t *dak_pub_hash,
+ size_t dak_pub_hash_size,
+ uint8_t *token_buf,
+ size_t token_buf_size,
+ size_t *token_size);
+
+#endif /* DELEGATED_ATTESTATION_H */
diff --git a/include/lib/psa/psa_manifest/sid.h b/include/lib/psa/psa_manifest/sid.h
index 580a4cf..bbd2e22 100644
--- a/include/lib/psa/psa_manifest/sid.h
+++ b/include/lib/psa/psa_manifest/sid.h
@@ -14,4 +14,7 @@
/******** PSA_SP_MEASURED_BOOT ********/
#define RSS_MEASURED_BOOT_HANDLE (0x40000110U)
+/******** PSA_SP_DELAGATED_ATTESTATION ********/
+#define RSS_DELEGATED_SERVICE_HANDLE (0x40000111U)
+
#endif /* PSA_MANIFEST_SID_H */
diff --git a/lib/psa/delegated_attestation.c b/lib/psa/delegated_attestation.c
new file mode 100644
index 0000000..5acab8e
--- /dev/null
+++ b/lib/psa/delegated_attestation.c
@@ -0,0 +1,230 @@
+/*
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include <string.h>
+
+#include <delegated_attestation.h>
+#include <psa/client.h>
+#include <psa_manifest/sid.h>
+
+#if !PLAT_RSS_NOT_SUPPORTED
+psa_status_t
+rss_delegated_attest_get_delegated_key(uint8_t ecc_curve,
+ uint32_t key_bits,
+ uint8_t *key_buf,
+ size_t key_buf_size,
+ size_t *key_size,
+ uint32_t hash_algo)
+{
+ psa_status_t status;
+ psa_invec in_vec[] = {
+ {&ecc_curve, sizeof(ecc_curve)},
+ {&key_bits, sizeof(key_bits)},
+ {&hash_algo, sizeof(hash_algo)}
+ };
+ psa_outvec out_vec[] = {
+ {key_buf, key_buf_size}
+ };
+
+ if (key_size == NULL) {
+ return PSA_ERROR_INVALID_ARGUMENT;
+ }
+
+ status = psa_call(RSS_DELEGATED_SERVICE_HANDLE,
+ RSS_DELEGATED_ATTEST_GET_DELEGATED_KEY,
+ in_vec, IOVEC_LEN(in_vec),
+ out_vec, IOVEC_LEN(out_vec));
+ if (status == PSA_SUCCESS) {
+ *key_size = out_vec[0].len;
+ }
+
+ return status;
+}
+
+psa_status_t
+rss_delegated_attest_get_token(const uint8_t *dak_pub_hash,
+ size_t dak_pub_hash_size,
+ uint8_t *token_buf,
+ size_t token_buf_size,
+ size_t *token_size)
+{
+ psa_status_t status;
+ psa_invec in_vec[] = {
+ {dak_pub_hash, dak_pub_hash_size}
+ };
+ psa_outvec out_vec[] = {
+ {token_buf, token_buf_size}
+ };
+
+ if (token_size == NULL) {
+ return PSA_ERROR_INVALID_ARGUMENT;
+ }
+
+ status = psa_call(RSS_DELEGATED_SERVICE_HANDLE,
+ RSS_DELEGATED_ATTEST_GET_PLATFORM_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;
+}
+
+
+#else /* !PLAT_RSS_NOT_SUPPORTED */
+
+static const uint8_t delegated_key[] = {
+ 0x20, 0x11, 0xC7, 0xF0, 0x3C, 0xEE, 0x43, 0x25, 0x17, 0x6E,
+ 0x52, 0x4F, 0x03, 0x3C, 0x0C, 0xE1, 0xE2, 0x1A, 0x76, 0xE6,
+ 0xC1, 0xA4, 0xF0, 0xB8, 0x39, 0xAA, 0x1D, 0xF6, 0x1E, 0x0E,
+ 0x8A, 0x5C, 0x8A, 0x05, 0x74, 0x0F, 0x9B, 0x69, 0xEF, 0xA7,
+ 0xEB, 0x1A, 0x41, 0x85, 0xBD, 0x11, 0x7F, 0x68
+}
+
+static const uint8_t platform_token[] = {
+ 0xD2, 0x84, 0x43, 0xA1, 0x01, 0x26, 0xA0, 0x59,
+ 0x02, 0xBE, 0xAA, 0x3A, 0x00, 0x01, 0x24, 0xFF,
+ 0x58, 0x20, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB,
+ 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB,
+ 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB,
+ 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB,
+ 0xAB, 0xAB, 0x3A, 0x00, 0x01, 0x24, 0xFB, 0x58,
+ 0x20, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6,
+ 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE,
+ 0xAF, 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6,
+ 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE,
+ 0xBF, 0x3A, 0x00, 0x01, 0x25, 0x00, 0x58, 0x21,
+ 0x01, 0xFA, 0x58, 0x75, 0x5F, 0x65, 0x86, 0x27,
+ 0xCE, 0x54, 0x60, 0xF2, 0x9B, 0x75, 0x29, 0x67,
+ 0x13, 0x24, 0x8C, 0xAE, 0x7A, 0xD9, 0xE2, 0x98,
+ 0x4B, 0x90, 0x28, 0x0E, 0xFC, 0xBC, 0xB5, 0x02,
+ 0x48, 0x3A, 0x00, 0x01, 0x24, 0xFA, 0x58, 0x20,
+ 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
+ 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB,
+ 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC,
+ 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD,
+ 0x3A, 0x00, 0x01, 0x24, 0xF8, 0x20, 0x3A, 0x00,
+ 0x01, 0x24, 0xF9, 0x00, 0x3A, 0x00, 0x01, 0x24,
+ 0xFD, 0x85, 0xA5, 0x05, 0x58, 0x20, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x60,
+ 0x01, 0x65, 0x42, 0x4C, 0x31, 0x5F, 0x32, 0x06,
+ 0x66, 0x53, 0x48, 0x41, 0x32, 0x35, 0x36, 0x02,
+ 0x58, 0x20, 0xF8, 0xB7, 0xCE, 0xAD, 0x9B, 0xE4,
+ 0x5A, 0x8F, 0x5C, 0x52, 0x6F, 0x0C, 0x05, 0x25,
+ 0x8F, 0xF3, 0xE9, 0x81, 0xDC, 0xBC, 0xF2, 0x05,
+ 0x7F, 0x33, 0xF6, 0xBB, 0xDC, 0xD9, 0x4D, 0xA2,
+ 0x34, 0x3A, 0xA5, 0x05, 0x58, 0x20, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x67,
+ 0x31, 0x2E, 0x37, 0x2E, 0x32, 0x2B, 0x30, 0x01,
+ 0x63, 0x42, 0x4C, 0x32, 0x06, 0x66, 0x53, 0x48,
+ 0x41, 0x32, 0x35, 0x36, 0x02, 0x58, 0x20, 0x3A,
+ 0xE5, 0x9E, 0x40, 0xA9, 0x6B, 0xD5, 0x29, 0x1C,
+ 0xAB, 0x7A, 0x5F, 0xBD, 0x1F, 0x9A, 0xA6, 0x52,
+ 0xFB, 0x77, 0x7D, 0xA3, 0xEC, 0x9C, 0x29, 0xBC,
+ 0xE6, 0x5B, 0x3B, 0x43, 0xFC, 0x9D, 0x26, 0xA5,
+ 0x05, 0x58, 0x20, 0xBF, 0xE6, 0xD8, 0x6F, 0x88,
+ 0x26, 0xF4, 0xFF, 0x97, 0xFB, 0x96, 0xC4, 0xE6,
+ 0xFB, 0xC4, 0x99, 0x3E, 0x46, 0x19, 0xFC, 0x56,
+ 0x5D, 0xA2, 0x6A, 0xDF, 0x34, 0xC3, 0x29, 0x48,
+ 0x9A, 0xDC, 0x38, 0x04, 0x67, 0x31, 0x2E, 0x35,
+ 0x2E, 0x30, 0x2B, 0x30, 0x01, 0x64, 0x52, 0x54,
+ 0x5F, 0x30, 0x06, 0x66, 0x53, 0x48, 0x41, 0x32,
+ 0x35, 0x36, 0x02, 0x58, 0x20, 0x47, 0x94, 0x9D,
+ 0x27, 0x33, 0x82, 0x45, 0x1A, 0xDD, 0x25, 0xF4,
+ 0x9A, 0x89, 0x6F, 0x5F, 0xD9, 0xB0, 0xE8, 0x14,
+ 0xD3, 0xA4, 0x9B, 0x53, 0xB0, 0x44, 0x0B, 0xCF,
+ 0x32, 0x1A, 0xC4, 0xD2, 0x65, 0xA5, 0x05, 0x58,
+ 0x20, 0xB3, 0x60, 0xCA, 0xF5, 0xC9, 0x8C, 0x6B,
+ 0x94, 0x2A, 0x48, 0x82, 0xFA, 0x9D, 0x48, 0x23,
+ 0xEF, 0xB1, 0x66, 0xA9, 0xEF, 0x6A, 0x6E, 0x4A,
+ 0xA3, 0x7C, 0x19, 0x19, 0xED, 0x1F, 0xCC, 0xC0,
+ 0x49, 0x04, 0x67, 0x30, 0x2E, 0x30, 0x2E, 0x37,
+ 0x2B, 0x30, 0x01, 0x64, 0x52, 0x54, 0x5F, 0x31,
+ 0x06, 0x66, 0x53, 0x48, 0x41, 0x32, 0x35, 0x36,
+ 0x02, 0x58, 0x20, 0xCD, 0x38, 0xBE, 0xC8, 0xB7,
+ 0xC0, 0x9E, 0xD5, 0x24, 0x30, 0xFE, 0xC8, 0xD0,
+ 0x19, 0x12, 0x56, 0xB2, 0x7A, 0xA5, 0x53, 0x6F,
+ 0xBC, 0x7D, 0x09, 0xCA, 0x11, 0xDD, 0x90, 0xD7,
+ 0xD6, 0x70, 0xFD, 0xA5, 0x05, 0x58, 0x20, 0xAA,
+ 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
+ 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
+ 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
+ 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0x04,
+ 0x60, 0x01, 0x60, 0x06, 0x66, 0x53, 0x48, 0x41,
+ 0x32, 0x35, 0x36, 0x02, 0x58, 0x20, 0x28, 0x3D,
+ 0x0C, 0x25, 0x22, 0x0C, 0x87, 0x46, 0xA0, 0x58,
+ 0x64, 0x6C, 0x0B, 0x14, 0x37, 0x39, 0x40, 0x9D,
+ 0x2D, 0x11, 0xD1, 0xCC, 0x54, 0x51, 0xB4, 0x29,
+ 0x22, 0xCD, 0x70, 0x92, 0x71, 0xC3, 0x3A, 0x00,
+ 0x01, 0x25, 0x01, 0x77, 0x77, 0x77, 0x77, 0x2E,
+ 0x74, 0x72, 0x75, 0x73, 0x74, 0x65, 0x64, 0x66,
+ 0x69, 0x72, 0x6D, 0x77, 0x61, 0x72, 0x65, 0x2E,
+ 0x6F, 0x72, 0x67, 0x3A, 0x00, 0x01, 0x24, 0xF7,
+ 0x71, 0x50, 0x53, 0x41, 0x5F, 0x49, 0x4F, 0x54,
+ 0x5F, 0x50, 0x52, 0x4F, 0x46, 0x49, 0x4C, 0x45,
+ 0x5F, 0x31, 0x3A, 0x00, 0x01, 0x24, 0xFC, 0x70,
+ 0x30, 0x36, 0x30, 0x34, 0x35, 0x36, 0x35, 0x32,
+ 0x37, 0x32, 0x38, 0x32, 0x39, 0x31, 0x30, 0x30,
+ 0x58, 0x40, 0x1E, 0x0D, 0x2B, 0xD8, 0x7A, 0xC9,
+ 0x2D, 0xCB, 0x73, 0xD1, 0x42, 0x2F, 0xBF, 0xDA,
+ 0x24, 0x71, 0xE2, 0xAF, 0xEA, 0x48, 0x60, 0x17,
+ 0x23, 0x75, 0x64, 0xAC, 0xCC, 0x23, 0xA2, 0x67,
+ 0xC4, 0xE7, 0x8F, 0x1C, 0x7C, 0x68, 0x49, 0x42,
+ 0x4D, 0xDA, 0xC6, 0xD6, 0x21, 0x1C, 0xAA, 0x00,
+ 0xDA, 0x1E, 0x68, 0x56, 0xA3, 0x48, 0xEE, 0xA7,
+ 0x92, 0xA9, 0x09, 0x83, 0x42, 0x04, 0x06, 0x9E,
+ 0x62, 0xBB
+};
+
+psa_status_t
+rss_delegated_attest_get_delegated_key(uint8_t ecc_curve,
+ uint32_t key_bits,
+ uint8_t *key_buf,
+ size_t key_buf_size,
+ size_t *key_size,
+ uint32_t hash_algo)
+{
+ (void)ecc_curve;
+ (void)key_bits;
+ (void)hash_algo;
+
+ if (key_buf_size < sizeof(delegated_key)) {
+ return PSA_ERROR_BUFFER_TOO_SMALL;
+ }
+
+ (void)memcpy(key_buf, delegated_key, sizeof(delegated_key));
+ *key_size = sizeof(delegated_key);
+
+ return PSA_SUCCESS;
+}
+psa_status_t
+rss_delegated_attest_get_token(const uint8_t *dak_pub_hash,
+ size_t dak_pub_hash_size,
+ uint8_t *token_buf,
+ size_t token_buf_size,
+ size_t *token_size)
+{
+ (void)dak_pub_hash;
+ (void)dak_pub_hash_size;
+
+ if (token_buf_size < sizeof(platform_token)) {
+ return PSA_ERROR_BUFFER_TOO_SMALL;
+ }
+
+ (void)memcpy(token_buf, platform_token, sizeof(platform_token));
+ *token_size = sizeof(platform_token);
+
+ return PSA_SUCCESS;
+}
+#endif /* !PLAT_RSS_NOT_SUPPORTED */