Add components for attestation service
In preparation for implementing the attestation service provider,
building block components have been add. This includes the
service access protocol definition, an external cbor library,
generic claim model and a concrete claim source for extracting
claims from a TCG event log.
This commit contains derived work, the following files are copied
from other projects:
components/service/attestation/claims/sources/event_log/tcg.h
Origin:
https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git
include/drivers/measured_boot/tcg.h
#a5394205e94b70faf7ddd34841528ec631711d1a
components/service/attestation/include/psa/initial_attestation.h
Origin:
https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git
interface/include/psa/initial_attestation.h
#9280ae9d898bffbb889e4796e51aab35a392ef82
Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: I5ed3e4ef7111a19b29643538ef3c47b3b6e1dd5c
diff --git a/components/service/attestation/include/psa/initial_attestation.h b/components/service/attestation/include/psa/initial_attestation.h
new file mode 100644
index 0000000..bc630ee
--- /dev/null
+++ b/components/service/attestation/include/psa/initial_attestation.h
@@ -0,0 +1,228 @@
+/*
+ * Copyright (c) 2018-2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+/***************************************************************************/
+/* DRAFT UNDER REVIEW */
+/* These APIs are still evolving and are meant as a prototype for review.*/
+/* The APIs will change depending on feedback and will be firmed up */
+/* to a stable set of APIs once all the feedback has been considered. */
+/***************************************************************************/
+
+#ifndef __PSA_INITIAL_ATTESTATION_H__
+#define __PSA_INITIAL_ATTESTATION_H__
+
+#include <limits.h>
+#include <stdint.h>
+#include <stddef.h>
+#include "psa/crypto.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief PSA INITIAL ATTESTATION API version
+ *
+ * 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: 32, 48, 64
+ * Challenge can be a nonce from server
+ * or the hash of some combined data : nonce + attested data by caller.
+ */
+#define PSA_INITIAL_ATTEST_CHALLENGE_SIZE_32 (32u)
+#define PSA_INITIAL_ATTEST_CHALLENGE_SIZE_48 (48u)
+#define PSA_INITIAL_ATTEST_CHALLENGE_SIZE_64 (64u)
+
+/**
+ * The maximum size of an attestation token that can be generated by the
+ * attestation service. Used to configure buffers for services that verify the
+ * produced tokens.
+ */
+#define PSA_INITIAL_ATTEST_MAX_TOKEN_SIZE (0x400)
+
+/**
+ * The list of fixed claims in the initial attestation token is still evolving,
+ * you can expect slight changes in the future.
+ *
+ * The initial attestation token is planned to be aligned with future version of
+ * Entity Attestation Token format:
+ * https://tools.ietf.org/html/draft-mandyam-eat-01
+ *
+ * Current list of claims:
+ * - Challenge: Input object from caller. Can be a single nonce from server
+ * or hash of nonce and attested data. It is intended to provide
+ * freshness to reports and the caller has responsibility to
+ * arrange this. Allowed length: 32, 48, 64 bytes. The claim is
+ * modeled to be eventually represented by the EAT standard
+ * claim nonce. Until such a time as that standard exists,
+ * the claim will be represented by a custom claim. Value
+ * is encoded as byte string.
+ *
+ * - Instance ID: It represents the unique identifier of the instance. In the
+ * PSA definition it is a hash of the public attestation key
+ * of the instance. The claim is modeled to be eventually
+ * represented by the EAT standard claim UEID of type GUID.
+ * Until such a time as that standard exists, the claim will be
+ * represented by a custom claim Value is encoded as byte
+ * string.
+ *
+ * - Verification service indicator: Optional, recommended claim. It is used by
+ * a Relying Party to locate a validation service for the token.
+ * The value is a text string that can be used to locate the
+ * service or a URL specifying the address of the service. The
+ * claim is modeled to be eventually represented by the EAT
+ * standard claim origination. Until such a time as that
+ * standard exists, the claim will be represented by a custom
+ * claim. Value is encoded as text string.
+ *
+ * - Profile definition: Optional, recommended claim. It contains the name of
+ * a document that describes the 'profile' of the token, being
+ * a full description of the claims, their usage, verification
+ * and token signing. The document name may include versioning.
+ * Custom claim with a value encoded as text string.
+ *
+ * - Implementation ID: It represents the original implementation signer of the
+ * attestation key and identifies the contract between the
+ * report and verification. A verification service will use this
+ * claim to locate the details of the verification process.
+ * Custom claim with a value encoded as byte string.
+ *
+ * - Security lifecycle: It represents the current lifecycle state of the
+ * instance. Custom claim with a value encoded as integer that
+ * is divided to convey a major state and a minor state. The
+ * PSA state and implementation state are encoded as follows:
+ * - version[15:8] - PSA lifecycle state - major
+ * - version[7:0] - IMPLEMENTATION DEFINED state - minor
+ * Possible PSA lifecycle states:
+ * - Unknown (0x1000u),
+ * - PSA_RoT_Provisioning (0x2000u),
+ * - Secured (0x3000u),
+ * - Non_PSA_RoT_Debug(0x4000u),
+ * - Recoverable_PSA_RoT_Debug (0x5000u),
+ * - Decommissioned (0x6000u)
+ *
+ * - Client ID: The partition ID of that secure partition or non-secure
+ * thread who called the initial attestation API. Custom claim
+ * with a value encoded as a *signed* integer. Negative number
+ * represents non-secure caller, positive numbers represents
+ * secure callers, zero is invalid.
+ *
+ * - HW version: Optional claim. Globally unique number in EAN-13 format
+ * identifying the GDSII that went to fabrication, HW and ROM.
+ * It can be used to reference the security level of the PSA-ROT
+ * via a certification website. Custom claim with a value is
+ * encoded as text string.
+
+ * - Boot seed: It represents a random value created at system boot time that
+ * will allow differentiation of reports from different system
+ * sessions. The size is 32 bytes. Custom claim with a value is
+ * encoded as byte string.
+ *
+ * - Software components: Recommended claim. It represents the software state
+ * of the system. The value of the claim is an array of CBOR map
+ * entries, with one entry per software component within the
+ * device. Each map contains multiple claims that describe
+ * evidence about the details of the software component.
+ *
+ * - Measurement type: Optional claim. It represents the role of the
+ * software component. Value is encoded as short(!) text
+ * string.
+ *
+ * - Measurement value: It represents a hash of the invariant software
+ * component in memory at start-up time. The value must be a
+ * cryptographic hash of 256 bits or stronger.Value is
+ * encoded as byte string.
+ *
+ * - Version: Optional claim. It represents the issued software version.
+ * Value is encoded as text string.
+ *
+ * - Signer ID: It represents the hash of a signing authority public key.
+ * Value is encoded as byte string.
+ *
+ * - Measurement description: Optional claim. It represents the way in which
+ * the measurement value of the software component is
+ * computed. Value is encoded as text string containing an
+ * abbreviated description (name) of the measurement method.
+ *
+ * - No software measurements: In the event that the implementation does not
+ * contain any software measurements then the software
+ * components claim above can be omitted but instead
+ * it is mandatory to include this claim to indicate this is a
+ * deliberate state. Custom claim a value is encoded as unsigned
+ * integer set to 1.
+ */
+
+/**
+ * \brief Get initial attestation token
+ *
+ * \param[in] auth_challenge Pointer to buffer where challenge input is
+ * stored. Nonce and / or hash of attested data.
+ * Must be always
+ * \ref PSA_INITIAL_ATTEST_TOKEN_SIZE bytes
+ * long.
+ * \param[in] challenge_size Size of challenge object in bytes.
+ * \param[out] token_buf Pointer to the buffer where attestation token
+ * will be stored.
+ * \param[in] token_buf_size Size of allocated buffer for token, in bytes.
+ * \param[out] token_size Size of the token that has been returned, in
+ * bytes.
+ *
+ * \return Returns error code as specified in \ref 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);
+
+/**
+ * \brief Get the exact size of initial attestation token in bytes.
+ *
+ * It just returns with the size of the IAT token. It can be used if the caller
+ * dynamically allocates memory for the token buffer.
+ *
+ * \param[in] challenge_size Size of challenge object in bytes. This must be
+ * a supported challenge size (as above).
+ * \param[out] token_size Size of the token in bytes, which is created by
+ * initial attestation service.
+ *
+ * \return Returns error code as specified in \ref psa_status_t
+ */
+psa_status_t
+psa_initial_attest_get_token_size(size_t challenge_size,
+ size_t *token_size);
+
+/**
+ * \brief Get the initial attestation public key.
+ *
+ * \param[out] public_key Pointer to the buffer where the public key
+ * will be stored.
+ * \param[in] key_buf_size Size of allocated buffer for key, in bytes.
+ * \param[out] public_key_len Size of public key in bytes.
+ * \param[out] public_key_curve Type of the elliptic curve which the key
+ * belongs to.
+ *
+ * \note Currently only the ECDSA P-256 over SHA-256 algorithm is supported.
+ *
+ * \return Returns error code as specified in \ref psa_status_t
+ */
+psa_status_t
+tfm_initial_attest_get_public_key(uint8_t *public_key,
+ size_t public_key_buf_size,
+ size_t *public_key_len,
+ psa_ecc_family_t *elliptic_curve_type);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __PSA_INITIAL_ATTESTATION_H__ */