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Implement TCG DICE TCB Info X509 Extension (#28)
Implement the TCG DICE TCB Info and Multi TCB Info X509 Extensions as defined in https://trustedcomputinggroup.org/wp-content/uploads/DICE-Attestation-Architecture-Version-1.1-Revision-18_pub.pdf
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6 files changed

+1005
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lines changed

‎CMakeLists.txt‎

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@@ -41,6 +41,7 @@ set(LIBNAT20_SOURCES
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# Add the core library source files here.
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src/core/asn1.c
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src/core/oid.c
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src/core/x509_ext_tcg_dice_tcb_info.c
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src/core/x509.c
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)
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@@ -50,13 +51,15 @@ set(LIBNAT20_PUB_HEADERS
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include/nat20/asn1.h
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include/nat20/crypto.h
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include/nat20/oid.h
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include/nat20/x509_ext_tcg_dice_tcb_info.h
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include/nat20/x509.h
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)
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set(LIBNAT20_TEST_SOURCES
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# Add test source files here.
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src/core/test/test.cpp
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src/core/test/asn1.cpp
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src/core/test/x509_ext_tcg_dice_tcb_info.cpp
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)
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set(LIBNAT20_DOC_PAGES

‎include/nat20/oid.h‎

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@@ -37,7 +37,7 @@
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* @sa N20_ASN1_DEFINE_OID
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* @sa N20_ASN1_DECLARE_OID
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*/
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#define N20_ASN1_MAX_OID_ELEMENTS 7
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#define N20_ASN1_MAX_OID_ELEMENTS 10
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/**
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* @brief Structure representing an object identifier.
@@ -129,6 +129,11 @@ N20_ASN1_DECLARE_OID(OID_EC_PUBLIC_KEY);
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N20_ASN1_DECLARE_OID(OID_SECP256R1);
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N20_ASN1_DECLARE_OID(OID_SECP384R1);
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N20_ASN1_DECLARE_OID(OID_SHA224);
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N20_ASN1_DECLARE_OID(OID_SHA256);
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N20_ASN1_DECLARE_OID(OID_SHA384);
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N20_ASN1_DECLARE_OID(OID_SHA512);
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N20_ASN1_DECLARE_OID(OID_ECDSA_WITH_SHA224);
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N20_ASN1_DECLARE_OID(OID_ECDSA_WITH_SHA256);
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N20_ASN1_DECLARE_OID(OID_ECDSA_WITH_SHA384);
@@ -144,4 +149,7 @@ N20_ASN1_DECLARE_OID(OID_COMMON_NAME);
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N20_ASN1_DECLARE_OID(OID_BASIC_CONSTRAINTS);
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N20_ASN1_DECLARE_OID(OID_KEY_USAGE);
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N20_ASN1_DECLARE_OID(OID_TCG_DICE_TCB_INFO);
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N20_ASN1_DECLARE_OID(OID_TCG_DICE_MULTI_TCB_INFO);
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/** @} */

‎include/nat20/x509_ext_tcg_dice_tcb_info.h‎

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/*
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* Copyright 2025 Aurora Operations, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/** @file */
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#pragma once
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#include <nat20/asn1.h>
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#include <nat20/oid.h>
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#include <stddef.h>
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @defgroup n20_x509_ext_tcg_dice_tcb_info_operational_flags_macros TCG DICE TCB Info Operational
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* Flags Macros.
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*
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* These macros set the corresponding flags in the operational flags (and mask)
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* bit mask of @ref n20_x509_ext_tcg_dice_tcb_info_operational_flags_t.
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* Each macro takes a pointer to an instance of
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* @ref n20_x509_ext_tcg_dice_tcb_info_operational_flags_t as its argument.
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*
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* See TCG DICE Attestation Architecture Version 1.1, Section 6.1.1.1.
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*
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* # Example
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*
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* @code{.c}
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* n20_x509_ext_tcg_dice_tcb_info_operational_flags_t operational_flags = {0};
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* N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_SECURE(&operational_flags);
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* @endcode
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* @{
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*/
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/**
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* @brief The target environment is not configured for normal operation.
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_CONFIGURED(operational_flags) \
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(operational_flags)->operational_flags_mask[0] |= 0x80
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/**
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* @brief The target environment is not secure.
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_SECURE(operational_flags) \
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(operational_flags)->operational_flags_mask[0] |= 0x40
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/**
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* @brief The target environment is recovering (e.g. from a failure).
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_RECOVERY(operational_flags) \
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(operational_flags)->operational_flags_mask[0] |= 0x20
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/**
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* @brief The target environment can be debuged.
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_DEBUG(operational_flags) \
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(operational_flags)->operational_flags_mask[0] |= 0x10
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/**
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* @brief The target environment is vulnerable to replay attack.
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_REPLAY_PROTECTED( \
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operational_flags) \
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(operational_flags)->operational_flags_mask[0] |= 0x08
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/**
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* @brief The target environment is vulneerable to modification by unauthorized updates.
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_INTEGRITY_PROTECTED( \
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operational_flags) \
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(operational_flags)->operational_flags_mask[0] |= 0x04
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/**
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* @brief The target environment is not measured after being loaded into memory.
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_RUNTIME_MEASURED( \
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operational_flags) \
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(operational_flags)->operational_flags_mask[0] |= 0x02
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/**
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* @brief The target environment is mutable.
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_IMMUTABLE(operational_flags) \
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(operational_flags)->operational_flags_mask[0] |= 0x01
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/**
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* @brief – The Target Environment measurements are not measurements of a Trusted Computing Base
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* (TCB).
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_TCB(operational_flags) \
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(operational_flags)->operational_flags_mask[1] |= 0x80
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/**
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* @brief Used to force a fixed width of for the OperationalFlags (and OperationalFlagsMask) bit
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* string.
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*/
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#define N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_FIXED_WIDTH(operational_flags) \
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(operational_flags)->operational_flags_mask[3] |= 0x01
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/**
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* @}
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*/
108+
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/**
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* @brief TCG DICE TCB Info Operational Flags.
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*
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* This type is used to populate the TCB Info Operational Flags and Operational Flags Mask
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* ASN.1 bitstrings.
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*
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* Always zero initialize instances of this structure and
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* set the flags using the @ref n20_x509_ext_tcg_dice_tcb_info_operational_flags_macros.
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*
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* # Example
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*
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* @code{.c}
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* n20_x509_ext_tcg_dice_tcb_info_operational_flags_t operational_flags = {0};
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* N20_X509_EXT_TCG_DICE_TCB_INFO_OPERATIONAL_FLAGS_SET_NOT_SECURE(&operational_flags);
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* @endcode
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*
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* (See TCG DICE Attestation Architecture Version 1.1, Section 6.1.1.1.)
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*/
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typedef struct n20_x509_ext_tcg_dice_tcb_info_operational_flags_s {
128+
/**
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* @brief The operational flags mask.
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*
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* Use the @ref n20_x509_ext_tcg_dice_tcb_info_operational_flags_macros to set the individual
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* bits of the operation flags mask. As described in
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* @ref n20_x509_ext_tcg_dice_tcb_info_operational_flags_t, there is no need to access this
134+
* field directly.
135+
*/
136+
uint8_t operational_flags_mask[4];
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} n20_x509_ext_tcg_dice_tcb_info_operational_flags_t;
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/**
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* @brief TCG DICE TCB FW ID.
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*
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* (See TCG DICE Attestation Architecture Version 1.1, Section 6.1.1.)
143+
*/
144+
typedef struct n20_x509_ext_tcg_dice_tcb_info_fwid_s {
145+
/**
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* @brief Hash algorithm OID of the algorithm used to generate the digest.
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*/
148+
n20_asn1_object_identifier_t hash_algo;
149+
/**
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* @brief Digest of firmware, initialization values, or other settings of the Target
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* Environment.
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*
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* If the digest buffer is NULL, no digest is added to the extension.
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*/
155+
n20_asn1_slice_t digest;
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} n20_x509_ext_tcg_dice_tcb_info_fwid_t;
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/**
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* @brief List of TCG DICE FWIDs.
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*
161+
* If the list is NULL, no FWIDs are inserted into the TCG DICE TCB Info extension.
162+
*/
163+
typedef struct n20_x509_ext_tcg_dice_tcb_info_fwid_list_s {
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/**
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* @brief List of FWIDs to include in the TCG DICE TCB Info extension.
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*/
167+
n20_x509_ext_tcg_dice_tcb_info_fwid_t const *list;
168+
/**
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* @brief Number of FWIDs in the list.
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*/
171+
size_t count;
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} n20_x509_ext_tcg_dice_tcb_info_fwid_list_t;
173+
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/**
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* @brief TCG DICE TCB Info X509 extension context.
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*
177+
* This is the context expected by
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* @ref n20_x509_ext_tcg_dice_tcb_info_content.
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* An instance of this object must be passed to the callback.
180+
* This is typically done using @ref n20_x509_extension by
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* initializing @ref n20_x509_extension_t.content_cb with
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* @ref n20_x509_ext_tcg_dice_tcb_info_content and setting
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* @ref n20_x509_extension_t.context to an instance of this
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* struct.
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*
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* (See TCG DICE Attestation Architecture Version 1.1, Section 6.1.1.)
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* @sa OID_TCG_DICE_TCB_INFO
188+
*/
189+
typedef struct n20_x509_ext_tcg_dice_tcb_info_s {
190+
/**
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* @brief The entity that created the measurement of the Target Environment.
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*
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* Must be a nul terminated UTF-8 encoded string.
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*
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* If NULL, vendor is not included in the generated extension.
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*/
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char const *vendor;
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/**
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* @brief The product name associated with the measurement of the Target Environment.
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*
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* Must be a nul terminated UTF-8 encoded string.
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*
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* If NULL, model is not included in the generated extension.
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*/
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char const *model;
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/**
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* @brief The revision string associated with the Target Environment.
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*
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* Must be a nul terminated UTF-8 encoded string.
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*
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* If NULL, version is not included in the generated extension.
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*/
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char const *version;
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/**
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* @brief The security version number associated with the Target Environment.
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*/
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int64_t svn;
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/**
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* @brief The DICE layer associated with this measurement of the Target Environment.
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*/
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int64_t layer;
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/**
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* @brief A value that distinguishes different instances of the same type of Target Environment.
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*/
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int64_t index;
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/**
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* @brief List of FWIDs to include in the extension.
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*
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* @sa n20_x509_ext_tcg_dice_tcb_info_fwid_list_t
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*/
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n20_x509_ext_tcg_dice_tcb_info_fwid_list_t fwids;
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/**
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* @brief A list of flags that enumerate potentially simultaneous operational states of the
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* Target Environment.
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*
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* @sa n20_x509_ext_tcg_dice_tcb_info_operational_flags_t
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*/
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n20_x509_ext_tcg_dice_tcb_info_operational_flags_t flags;
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/**
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* @brief Used to commumicate which bits in @ref flags are meaningful.
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*
242+
* When a bit is set here, the bit at the corresponding position in @ref flags is meaninful to
243+
* the verifier.
244+
*
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* @sa n20_x509_ext_tcg_dice_tcb_info_operational_flags_t
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*/
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n20_x509_ext_tcg_dice_tcb_info_operational_flags_t flags_mask;
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/**
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* @brief Vendor supplied values that encode vendor, model, or device specific state.
250+
*
251+
* If vender_info.buffer is NULL vendor info is not included in the generated extension.
252+
*/
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n20_asn1_slice_t vendor_info;
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/**
255+
* @brief A machine readable description of the measurement.
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*
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* If type.buffer is NULL, type is not included in the generated extension.
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*/
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n20_asn1_slice_t type;
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} n20_x509_ext_tcg_dice_tcb_info_t;
261+
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/**
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* @brief Renders the value of a TCG DICE TCB Info X509 extension.
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*
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* The function expects a pointer to an instance of
266+
* @ref n20_x509_ext_tcg_dice_tcb_info_t as @ref context argument.
267+
*
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* If @ref context is NULL, nothing is rendered, which would leave
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* the resulting TCG DICE TCB Info extension malformed.
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*
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* This function is typically not used directly but instead
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* passed to @ref n20_x509_extension by initializing an
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* instance of @ref n20_x509_extensions_t
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* (See @ref n20_x509_extension for an example).
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*/
276+
extern void n20_x509_ext_tcg_dice_tcb_info_content(n20_asn1_stream_t *const s, void *context);
277+
278+
/**
279+
* @brief TCG DICE Multi TCB Info X509 extension context.
280+
*
281+
* This is the context expected by
282+
* @ref n20_x509_ext_tcg_dice_multi_tcb_info_content.
283+
* An instance of this object must be passed to the callback.
284+
* This is typically done using @ref n20_x509_extension by
285+
* initializing @ref n20_x509_extension_t.content_cb with
286+
* @ref n20_x509_ext_tcg_dice_multi_tcb_info_content and setting
287+
* @ref n20_x509_extension_t.context to an instance of this
288+
* struct.
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*
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* (See TCG DICE Attestation Architecture Version 1.1, Section 6.1.2.)
291+
* @sa OID_TCG_DICE_MULTI_TCB_INFO
292+
*/
293+
typedef struct n20_x509_ext_tcg_dice_multi_tcb_info_s {
294+
/**
295+
* @brief List of TCB Info to include in the extension.
296+
*
297+
* If NULL, no list is rendered in the extension.
298+
*
299+
* @sa n20_x509_ext_tcg_dice_tcb_info_t
300+
*/
301+
n20_x509_ext_tcg_dice_tcb_info_t const *list;
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/**
303+
* @brief Number of elements in the list.
304+
*/
305+
size_t count;
306+
} n20_x509_ext_tcg_dice_multi_tcb_info_t;
307+
308+
/**
309+
* @brief Renders the value of a TCG DICE Multi TCB Info X509 extension.
310+
*
311+
* The function expects a pointer to an instance of
312+
* @ref n20_x509_ext_tcg_dice_multi_tcb_info_t as @ref context argument.
313+
*
314+
* If @ref context is NULL, or the list is NULL or number of elements in the list is 0, nothing is
315+
* rendered, which would leave the resulting TCG DICE Multi TCB Info extension malformed.
316+
*
317+
* This function is typically not used directly but instead
318+
* passed to @ref n20_x509_extension by initializing an
319+
* instance of @ref n20_x509_extensions_t
320+
* (See @ref n20_x509_extension for an example).
321+
*/
322+
extern void n20_x509_ext_tcg_dice_multi_tcb_info_content(n20_asn1_stream_t *const s, void *context);
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#ifdef __cplusplus
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}
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#endif

‎src/core/oid.c‎

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Original file line numberDiff line numberDiff line change
@@ -28,6 +28,11 @@ N20_ASN1_DEFINE_OID(OID_SECP256R1, 1, 2, 840, 10045, 3, 1, 7);
2828
/* Also known as NIST P-384 */
2929
N20_ASN1_DEFINE_OID(OID_SECP384R1, 1, 3, 132, 0, 34);
3030

31+
N20_ASN1_DEFINE_OID(OID_SHA224, 2, 16, 840, 1, 101, 3, 4, 2, 4);
32+
N20_ASN1_DEFINE_OID(OID_SHA256, 2, 16, 840, 1, 101, 3, 4, 2, 1);
33+
N20_ASN1_DEFINE_OID(OID_SHA384, 2, 16, 840, 1, 101, 3, 4, 2, 2);
34+
N20_ASN1_DEFINE_OID(OID_SHA512, 2, 16, 840, 1, 101, 3, 4, 2, 3);
35+
3136
N20_ASN1_DEFINE_OID(OID_ECDSA_WITH_SHA224, 1, 2, 840, 10045, 4, 3, 1);
3237
N20_ASN1_DEFINE_OID(OID_ECDSA_WITH_SHA256, 1, 2, 840, 10045, 4, 3, 2);
3338
N20_ASN1_DEFINE_OID(OID_ECDSA_WITH_SHA384, 1, 2, 840, 10045, 4, 3, 3);
@@ -42,3 +47,6 @@ N20_ASN1_DEFINE_OID(OID_COMMON_NAME, 2, 5, 4, 3);
4247

4348
N20_ASN1_DEFINE_OID(OID_BASIC_CONSTRAINTS, 2, 5, 29, 19);
4449
N20_ASN1_DEFINE_OID(OID_KEY_USAGE, 2, 5, 29, 15);
50+
51+
N20_ASN1_DEFINE_OID(OID_TCG_DICE_TCB_INFO, 2, 23, 133, 5, 4, 1);
52+
N20_ASN1_DEFINE_OID(OID_TCG_DICE_MULTI_TCB_INFO, 2, 23, 133, 5, 4, 5);

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