Remote ATtestation ProcedureS D. Glaze
Internet-Draft Google LLC
Intended status: Standards Track 10 December 2024
Expires: 13 June 2025
CoRIM profile for AMD SEV-SNP attestation report
draft-deeglaze-amd-sev-snp-corim-profile-02
Abstract
AMD Secure Encrypted Virtualization with Secure Nested Pages (SEV-
SNP) attestation reports comprise of reference values and
cryptographic key material that a Verifier needs in order to appraise
Attestation Evidence produced by an AMD SEV-SNP virtual machine.
This document specifies the information elements for representing
SEV-SNP Reference Values in CoRIM format.
Discussion Venues
This note is to be removed before publishing as an RFC.
Source for this draft and an issue tracker can be found at
https://github.com/deeglaze/draft-deeglaze-amd-sev-snp-corim-profile.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on 13 June 2025.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. AMD SEV-SNP Attestation Reports . . . . . . . . . . . . . . . 3
3.1. AMD SEV-SNP CoRIM Profile . . . . . . . . . . . . . . . . 4
3.1.1. AMD SEV-SNP Target Environment . . . . . . . . . . . 4
3.1.2. AMD SEV-SNP Attestation Report measurements . . . . . 5
3.1.2.1. AMD SEV-SNP measurements . . . . . . . . . . . . 5
3.1.3. AMD SEV-SNP Evidence Translation to
reference-triple-record . . . . . . . . . . . . . . . 7
3.1.3.1. environment . . . . . . . . . . . . . . . . . . . 7
3.1.3.2. measurement-map . . . . . . . . . . . . . . . . . 8
3.1.3.3. cmtype . . . . . . . . . . . . . . . . . . . . . 10
3.1.3.4. Optional: ID block as reference value . . . . . . 11
3.1.3.5. VEK Certificate attest-key-triple-record . . . . 11
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
4.1. New CBOR Tags . . . . . . . . . . . . . . . . . . . . . . 13
4.2. New media types . . . . . . . . . . . . . . . . . . . . . 13
4.2.1. application/vnd.amd.sev-snp.attestation-report . . . 13
4.2.2. application/vnd.amd.ghcb.guid-table . . . . . . . . . 13
4.3. New CoAP Content-Formats entries . . . . . . . . . . . . 14
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1. Normative References . . . . . . . . . . . . . . . . . . 14
5.2. Informative References . . . . . . . . . . . . . . . . . 15
Appendix A. CoRIM Extensions CDDL . . . . . . . . . . . . . . . 15
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
This profile describes the extensions and restrictions placed on
Reference Values, Endorsements, and Evidence that support the
attestation capabilities of AMD products that provide Securet
Encrypted Virtualization with Secure Nested Pages (SEV-SNP).
CoRIM ([I-D.ietf-rats-corim]) defines a baseline CDDL for Reference
Values and Endorsements that this profile extends. Some measurement
types of the baseline CDDL are not used in this profile. The AMD
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SEV-SNP attestation report byte format is specified by AMD. The
profile defines a transformation from the AMD byte format into a
CoMID representation for use in appraisal.
This profile is meant for expressing reference values and
endorsements of specific environments. It is not meant to encode
complex policy decisions about the acceptability of measurements.
The accepted claim set construction (ACS) this profile enables does
lay a foundation for policy engines that enable further evaluation
over complete ACS constructions.
This profile extends the flags-map to represent the guest policy and
host platform info that are unique to AMD SEV-SNP. The profile
extends the $crypto-key-type-choice to represent the SHA-384 digest
of a key in AMD format from Appendix: Digital Signatures of
[SEV-SNP.API].
2. Conventions and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 RFC2119 [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The reader is assumed to be familiar with the terms defined in
[I-D.ietf-rats-corim] and Section 4 of [RFC9334]. The syntax of data
descriptions is CDDL as specified in [RFC8610]. Fields of the AMD
SEV-SNP ATTESTATION_REPORT are referred to by their assigned names in
[SEV-SNP.API].
3. AMD SEV-SNP Attestation Reports
The AMD SEV-SNP attestation scheme in [SEV-SNP.API] contains
measurements of security-relevant configuration of the host
environment and the launch configuration of a SEV-SNP VM. This draft
documents the normative representation of attestation report Evidence
as a CoRIM profile.
AMD-SP: AMD Secure Processor. A separate core that provides the
confidentiality and integrity properties of AMD SEV-SNP. The
function that is relevant to this document is its construction of
signed virtual machine attestation reports.
[VCEK]: Versioned Chip Endorsement Key. A key for signing the SEV-
SNP Attestation Report. The key is derived from a unique device
secret as well as the security patch levels of relevant host
components.
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[VLEK]: Version Loaded Endorsement Key. An alternative SEV-SNP
Attestation Report signing key that is derived from a secret shared
between AMD and a Cloud Service Provider. The key is encrypted with
a per-device per-version wrapping key that is then decrypted and
stored by the AMD-SP.
VEK: Either a VCEK or VLEK.
3.1. AMD SEV-SNP CoRIM Profile
AMD SEV-SNP launch endorsements are carried in one or more CoMIDs
inside a CoRIM.
The profile attribute in the CoRIM MAY be present to specify a
further restriction on this profile. The base requirements of this
profile MAY be specified by tag:amd.com,2024:snp-corim-profile
Figure 1.
/ corim-map / {
/ corim.profile / 3: [
32("tag:amd.com,2024/snp-corim-profile")
]
/ ... /
}
Figure 1: SEV-SNP attestation profile version 1, CoRIM profile
3.1.1. AMD SEV-SNP Target Environment
The ATTESTATION_REPORT structure as understood in the RATS
Architecture [RFC9334] is a signed collection of Claims that
constitute Evidence about the Target Environment. The Attester for
the ATTESTATION_REPORT is specialized hardware that will only run
AMD-signed firmware.
The instance identifier can be argued as any of REPORT_ID,
REPORT_ID_MA when non-zero, CHIP_ID (for VCEK), or CSP_ID (for VLEK).
Given that REPORT_ID and REPORT_ID_MA are more ephemeral measured
values and not the instance of the AMD-SP as the attesting
environment, they are relegated to measurements. Any endorsement of
VM instances specific to either the REPORT_ID or REPORT_ID_MA values
SHOULD use a conditional endorsement triple.
The different notions of identity induce different classes of
attestation to identify target environments. The different classes
of attestation are
* By chip: The environment-map / instance is 560(CHIP_ID).
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* By CSP: The environment-map / instance is 560(CSP_ID).
The CSP_ID is only evident from the VLEK certificate, which uses the
ASN.1 IA5String encoding. For the tagged-bytes representation,
however, the CSP_ID SHALL be the UTF-8 encoding of the text string.
The class-id for the Target Environment measured by the AMD-SP is a
tagged OID that corresponds to the attestation class:
* By chip: 1.3.6.1.4.1.3704.3.1 (111(h'06092b060104019c780301'))
* By CSP: 1.3.6.1.4.1.3704.3.2 (111(h'06092b060104019c780302'))
The model field MUST NOT be present in the environment-map, as it is
error-prone to determine for VERSION 2, and redundant with fields
added in VERSION 3.
The rest of the class-map MUST remain empty, since class is compared
for deterministic CBOR binary encoding equality.
The group is free for a CoRIM issuer to assign.
If the SIGNING_KEY bit of the attestation report is 1 indicating VLEK
use, then the class-id MUST NOT be by chip.
/ environment-map / {
/ class-map / {
/ class-id: / 0 => #6.111(h'06092b060104019c780301')
}
/ instance: / 1 => #6.560(CHIP_ID)
}
3.1.2. AMD SEV-SNP Attestation Report measurements
The fields of an attestation report are named by mkey numbers that
map to appropriate measurement-values-map values. This profile
defines no new measurement-values-map extensions for the
$$measurement-values-map-extensions socket. Flag-like values are
delegated to the raw-value and raw-value-mask measurement values.
3.1.2.1. AMD SEV-SNP measurements
The measurements in an ATTESTATION_REPORT are each assigned an mkey
value and the field value is translated to an appropriate
measurement-values-map entry. The convention for mkey value
assignment is to sequential ordering when there are no reserved bits.
The mkey following a reserved bit is the bit position in the report
of the start of the value. The R[lo:hi] notation will reference the
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attestation report byte slice from offset lo inclusive to hi
exclusive. The leuintN type is another name for a byte string, but
with the interpretation that it represents an unsigned integer with N
bit width.
*mkey 0*: VERSION. Expressed as &(raw-value: 4): tagged-leuint32.
*mkey 1*: GUEST_SVN. Expressed as &(raw-value: 4): tagged-bytes4.
*mkey 2*: POLICY. Expressed as &(raw-value: 4): tagged-bytes8 with
optional &(raw-value-mask: 5): tagged-bytes8 to restrict the
reference value to the masked bits.
*mkey 3*: FAMILY_ID. Expressed as &(raw-value: 4): tagged-bytes16.
*mkey 4*: IMAGE_ID. Expressed as &(raw-value: 4): tagged-bytes16.
*mkey 5*: VMPL. Expressed as &(raw-value: 4): tagged-leuint32.
*SIGNATURE_ALGO skipped*: R[0x034:0x38] only needed for signature
verification.
*mkey 6*: CURRENT_TCB. Expressed as &(svn: 1): svn-type .and
svn64-type
*mkey 7*: PLATFORM_INFO. Expressed as &(raw-value: 4): tagged-bytes8
with optional &(raw-value-mask: 5): tagged-bytes8 to restrict the
reference value to the masked bits.
*AUTHOR_KEY_EN skipped*: AUTHOR_KEY_DIGEST will be present in
evidence if and only if this bit is 1. *MASK_CHIP_KEY skipped*:
CHIP_ID will be present in evidence if and only if this bit is 0.
*SIGNING_KEY skipped*: The environment's class is determined by the
attestation key kind.
*mkey 640*: REPORT_DATA. Expressed as &(raw-value: 4): tagged-
bytes64.
*mkey 641*: MEASUREMENT. Expressed as &(digests: 2): [[7, bytes48]].
*mkey 642*: HOST_DATA. Expressed as &(digests: 2): [[7, bytes48]].
*mkey 643*: ID_KEY_DIGEST. Expressed as &(digests: 2): [[7,
bytes48]].
*mkey 644*: AUTHOR_KEY_DIGEST. Expressed as &(digests: 2): [[7,
bytes48]].
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*mkey 645*: REPORT_ID. Expressed as &(raw-value: 4): tagged-bytes32
*mkey 646*: REPORT_ID_MA. Expressed as &(raw-value: 4): tagged-
bytes32
*mkey 647*: REPORTED_TCB Expressed as &(svn: 1): svn64-type.
*mkey 648*: CPUID_FAM_ID. Expressed as &(raw-value: 4): tagged-byte.
*mkey 649*: CPUID_MOD_ID. Expressed as &(raw-value: 4): tagged-byte.
*mkey 650*: CPUID_STEP. Expressed as &(raw-value: 4): tagged-byte.
*mkey 3328*: CHIP_ID. Expressed as &(raw-value: 4): tagged-bytes64.
*mkey 3329*: COMMITTED_TCB: Expressed as &(svn: 1): svn64-type.
*mkey 3330*: CurrentVersion. Expressed as &(version: 0): semver-
version-map
*mkey 3936*: CommittedVersion. Expressed as &(version: 0): semver-
version-map
*mkey 3968*: LAUNCH_TCB. Expressed as &(svn: 1): svn64-type.
3.1.3. AMD SEV-SNP Evidence Translation to reference-triple-record
The ATTESTATION_REPORT Evidence is converted into a CoRIM internal
representation given the canonical translation from a reference-
triple-record as evidence conceptual message.
3.1.3.1. environment
If SIGNING_KEY is 0
* The environment-map / class / class-id field SHALL be set to
111(h'06092b060104019c780301').
* The environment-map / instance field
- MAY be 560(CHIP_ID) only if MASK_CHIP_KEY is 0, or
- MAY be 560(hwid) where hwid is from the VCEK certificate
extension value of 1.3.6.1.4.1.3704.1.4.
If SIGNING_KEY is 1
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* The environment-map / class / class-id field SHALL be set to
111(h'06092b060104019c780302').
* The environment-map / instance field SHALL be 560(CSP_ID).
The Verifier is free add a group according to vendor-defined rules.
3.1.3.2. measurement-map
The translation makes use of the following metafunctions:
* The function dec(b) represents a byte in its decimal string
rendering.
Juxtaposition of expressions with string literals is interpreted with
string concatenation.
Note: A value of 0 is not treated the same as unset given the
semantics for matching flags-map.
*no mkey*:
The &(flags: 3) codepoint SHALL be set to a flags-map with the
following construction:
* is-confidentiality-protected MAY be set to true.
* is-integrity-protected MAY be set to true.
* is-replay-protected MAY be set to true.
* is-debug SHALL be set to the truth value of bit 19 of POLICY.
*mkey 0*: VERSION. The codepoint &(raw-value: 4) SHALL be set to
560(R[0x000:0x004]).
*mkey 1*: GUEST_SVN. 4 bytes. The codepoint &(raw-value: 4) SHALL be
set to 560(R[0x004:0x008]).
*mkey 2*: POLICY. 8 bytes. The codepoint &(raw-value: 4) SHALL be
set to 560:(R[0x008:0x010]) with optional &(raw-value-mask: 5):
tagged-bytes to restrict the reference value to the masked bits.
*mkey 3*: FAMILY_ID. 16 bytes. The codepoint &(raw-value: 4) SHALL
be set to 560:(R[0x010:0x020]).
*mkey 4*: IMAGE_ID. 16 bytes. The codepoint &(raw-value: 4) SHALL be
set to 560:(R[0x020:0x030]).
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*mkey 5*: VMPL. 4 bytes. The codepoint &(raw-value: 4) SHALL be set
to 560:(R[0x030:0x034]).
*SIGNATURE_ALGO skipped*: R[0x034:0x38] only needed for signature
verification.
*mkey 6*: CURRENT_TCB. The codepoint &(svn: 1) SHALL be set to
552(current_tcb) where current_tcb is R[0x038:0x40] translated to
uint from its little-endian representation.
*mkey 7*: PLATFORM_INFO. The codepoint &(raw-value: 4) SHALL be set
to 560(R[0x040:0x048]).
*AUTHOR_KEY_EN skipped*: AUTHOR_KEY_DIGEST will be present in
evidence if and only if this bit is 1. *MASK_CHIP_KEY skipped*:
CHIP_ID will be present in evidence if and only if this bit is 0.
*SIGNING_KEY skipped*: The environment's class is determined by the
attestation key kind.
*mkey 640*: REPORT_DATA. The codepoint &(raw-value: 4) SHALL be set
to 560(R[0x050:0x090]).
*mkey 641*: MEASUREMENT. The codepoint &(digests: 2) SHALL be set to
[[7, R[0x090:0x0C0]]].
**mkey 642: HOST_DATA. The codepoint &(digests: 2) SHALL be set to
[[7, R[0x0C0:0x0E0]]].
*mkey 643*: ID_KEY_DIGEST. The codepoint &(digests: 2): [[7,
R[0x0E0:0x110]]] SHALL be set.
*mkey 644*: AUTHOR_KEY_DIGEST. The codepoint &(digests: 2) SHALL be
set to [[7, R[0x110:0x140]]] only if AUTHOR_KEY_EN (R[0x048] & 1) is
1.
*mkey 645*: REPORT_ID. The codepoint &(raw-value: 4) SHALL be set to
560(R[0x140:0x160])
*mkey 646*: REPORT_ID_MA. The codepoint &(raw-value: 4) SHALL be set
to 560(R[0x160:0x180]) only if non-zero.
*mkey 647*: REPORTED_TCB The codepoint &(svn: 1) SHALL be set to
552(reported_tcb) where reported_tcb is REPORTED_TCB (R[0x180:0x188])
translated to uint from its little-endian representation.
*mkey 648*: CPUID_FAM_ID. The codepoint &(raw-value: 4) SHALL be set
to 560(R[0x188:0x189]) only if VERSION (little endian R[0x000:0x004])
is at least 3.
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*mkey 649*: CPUID_MOD_ID. The codepoint &(raw-value: 4) SHALL be set
to 560(R[0x189:0x18A]) only if VERSION (little endian R[0x000:0x004])
is at least 3.
*mkey 650*: CPUID_STEP. The codepoint &(raw-value: 4) SHALL be set
to 560(R[0x18A:0x18B]) only if VERSION (little endian R[0x000:0x004])
is at least 3.
*mkey 3328*: CHIP_ID. The codepoint &(raw-value: 4) SHALL be set to
560(R[0x1A0:0x1E0]) only if MASK_CHIP_KEY (R[0x048] & 2) is 0.
*mkey 3329*: COMMITTED_TCB. The codepoint &(svn: 1) SHALL be set to
552(committed_tcb) where committed_tcb is REPORTED_TCB
(R[0x1E0:0x1E8]) translated to uint from its little-endian
representation.
*mkey 3330*: CurrentVersion. The &(version: 0) codepoint SHALL be
set to
/ version-map / {
/ version: 0 / vstr
/ version-scheme: / 1: 16384
}
The version string vstr is constructed as dec(R[0x1EA]) '.'
dec(R[0x1E9]) '.' dec(R[0x1E8]).
*mkey 3936*: CommittedVersion. The &(version: 0) codepoint SHALL be
set to
/ version-map / {
/ version: 0 / vstr
/ version-scheme: / 1: 16384
}
The version string vstr is constructed as dec(R[0x1EE]) '.'
dec(R[0x1ED]) '.' dec(R[0x1EC]).
*mkey 3968*: LAUNCH_TCB. The codepoint &(svn: 1) SHALL be set to
552(launch_tcb) where launch_tcb is LAUNCH_TCB (R[0x1F0:0x1F8])
translated to uint from its little-endian representation.
3.1.3.3. cmtype
The cmtype SHALL be evidence: 2.
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3.1.3.4. Optional: ID block as reference value
If an ID block is provided at VM launch, it is authenticated by an ID
key. The ID block authentication is checked by the AMD-SP firmware.
The firmware will only launch the VM if the authenticated policy
matches. The firmware indicates that the authentication passed by
populating fields of the attestation report to bind the evidence to
the authentication key(s) ID_KEY_DIGEST and/or AUTHOR_KEY_DIGEST.
The ID block authentication as reference value SHALL NOT be retained
by the Verifier to apply to another appraisal session. The reference
value qualification is meant to be considered valid only for the
duration of the appraisal session.
The Verifier MAY allocate an rv for an addition ECT to represent the
authentication at SNP_LAUNCH_FINISH.
* The environment SHALL be equal to the environment of the evidence
ECT.
* The element-list SHALL contain two element-map entries
- The first element-map SHALL set element-id to 0 and the
element-claims to a copy of the evidence claims for element-id:
0.
- The second element-map SHALL set element-id to 1 and the
element-claims to a copy of the evidence claims for element-id:
1.
* The authority SHALL be an array containing #6.TBD(ID_KEY_DIGEST)
and #6.TBD(AUTHOR_KEY_DIGEST) if nonzero. The Verifier MAY add
more encodings of the same keys.
* The cmtype SHALL be set to reference-values: 0
3.1.3.5. VEK Certificate attest-key-triple-record
Each VEK Certificate from AMD's Key Distribution Service (KDS)
contains extensions that associate the key to its target environment.
There is no condition on REPORTED_TCB to form this association, since
the keys will only ever verify evidence that corresponds the the
REPORTED_TCB they were derived from.
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To allow for certificates to be reissued, the keys associated to an
environment use only the SubjectPublicKeyInfo. For consistent
comparison, the $crypto-key-type-choice encoding is a #6.557-tagged
SHA256 digest (alg: 1) of the ASN.1 encoding as defined in [RFC5280].
Let vcek_pk represent the tagged key identifier of the VCEK public
key.
A [VCEK] certificate may be interpreted with hwid as the octet-string
value from X.509 extension 1.3.6.1.4.1.3704.1.4 as
[ / environment-map / {
&(class: 0): / class-map / {
&(class-id: 0): 111(h'06092b060104019c780301'),
},
&(instance: 2): 560(hwid)
},
[ vcek_pk ]
]
Note: KDS may not encode the hwid with the octet string type tag 0x04
and length information (definite, short, 64) 0x40 of the x.509
extension value. If the length is 64 bytes, then that is the exact
hwid.
Let vlek_pk be the encoded VLEK public key. A [VLEK] certificate
SHALL be associated with an environment with a "by CSP" class-id and
instance value as a tagged-bytes of the UTF-8 encoded csp_id string
from X.509 extension 1.3.6.1.4.1.3704.1.5 as
[ / environment-map / {
&(class: 0): / class-map / {
&(class-id: 0): 111(h'06092b060104019c780302'),
},
&(instance: 2): 560(csp_id)
},
[ vlek_pk ]
]
It is expected that the Verifier will require or admit a trust anchor
that associates the AMD root key and AMD SEV key certificates for a
product_name (from KDS endpoint vcek/v1/{product_name}/cert_chain or
vlek/v1/{product_name}/cert_chain) with the appropriate environment
class in order to validate the attestation key certificates. If
using a CoTS [I-D.ietf-rats-concise-ta-stores] tag for trust anchor
specification, an appropriate purpose for verifying a VEK cerificate
is "eat".
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4. IANA Considerations
4.1. New CBOR Tags
IANA is requested to allocate the following tags in the "CBOR Tags"
registry [IANA.cbor-tags].
+=======+===========+====================+===========+
| Tag | Data Item | Semantics | Reference |
+=======+===========+====================+===========+
| 32780 | bytes | A digest of an AMD | RFCthis |
| | | public key format. | |
+-------+-----------+--------------------+-----------+
Table 1: Added CBOR tags
4.2. New media types
4.2.1. application/vnd.amd.sev-snp.attestation-report
A byte string that is expected to be interpreted as an AMD SEV-SNP
ATTESTATION_REPORT.
4.2.2. application/vnd.amd.ghcb.guid-table
An byte string that follows the [GHCB]'s GUID table ABI, which is the
same as the [SVSM] service manifest ABI, recounted here. A GUID
table is a header followed by an byte string body. The header is a
sequence of entries described in Table 2 terminated by an all zero
entry. After the all zero entry are the bytes that the header
entries index into.
+===========+========+===================================+
| Type | Name | Description |
+===========+========+===================================+
| UUID | GUID | An [RFC4122] byte format UUID |
+-----------+--------+-----------------------------------+
| LE_UINT32 | Offset | An offset into the the GUID table |
+-----------+--------+-----------------------------------+
| LE_UINT32 | Length | A byte length of the span |
+-----------+--------+-----------------------------------+
Table 2: guid_table_entry type description
An LE_UINT32 is a 4 byte byte string that represents a nonnegative
integer in little-endian order.
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Note that an offset is from the start of the byte string, and not
from the start of the octets following the zero entry of the header.
A header entry is valid if its Offset+Length is less than or equal to
the size of the entire GUID table.
4.3. New CoAP Content-Formats entries
The content types application/vnd.amd.sev-snp.attestation-
reportandapplication/vnd.amd.ghcb.guid-tableneed Content-Formats IDs
to be used in the EATmeasurements` claim. Requesting 10572 and 10573
respectively.
5. References
5.1. Normative References
[I-D.ietf-rats-corim]
Birkholz, H., Fossati, T., Deshpande, Y., Smith, N., and
W. Pan, "Concise Reference Integrity Manifest", Work in
Progress, Internet-Draft, draft-ietf-rats-corim-06, 18
October 2024, <https://datatracker.ietf.org/doc/html/
draft-ietf-rats-corim-06>.
[IANA.cbor-tags]
IANA, "Concise Binary Object Representation (CBOR) Tags",
<https://www.iana.org/assignments/cbor-tags>.
[IANA.named-information]
IANA, "Named Information",
<https://www.iana.org/assignments/named-information>.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/rfc/rfc4122>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
Definition Language (CDDL): A Notational Convention to
Express Concise Binary Object Representation (CBOR) and
JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
June 2019, <https://www.rfc-editor.org/rfc/rfc8610>.
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[RFC9334] Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
W. Pan, "Remote ATtestation procedureS (RATS)
Architecture", RFC 9334, DOI 10.17487/RFC9334, January
2023, <https://www.rfc-editor.org/rfc/rfc9334>.
5.2. Informative References
[GHCB] Advanced Micro Devices Inc., "SEV-ES Guest-Hypervisor
Communication Block Standardization", Revision 2.03 , July
2023, <https://www.amd.com/content/dam/amd/en/documents/
epyc-technical-docs/specifications/56421.pdf>.
[I-D.ietf-rats-concise-ta-stores]
Wallace, C., Housley, R., Fossati, T., and Y. Deshpande,
"Concise TA Stores (CoTS)", Work in Progress, Internet-
Draft, draft-ietf-rats-concise-ta-stores-02, 5 December
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
rats-concise-ta-stores-02>.
[SEV-SNP.API]
Advanced Micro Devices Inc., "SEV Secure Nested Paging
Firmware ABI Specification", Revision 1.55 , September
2023, <https://www.amd.com/content/dam/amd/en/documents/
epyc-technical-docs/specifications/56860.pdf>.
[SVSM] Advanced Micro Devices Inc., "Secure VM Services Module",
Revision 1.00 , July 2023,
<https://www.amd.com/content/dam/amd/en/documents/epyc-
technical-docs/specifications/58019.pdf>.
[VCEK] Advanced Micro Devices Inc., "Versioned Chip Endorsement
Key (VCEK) Certificate and KDS Interface Specification",
Revision 0.51 , January 2023,
<https://www.amd.com/content/dam/amd/en/documents/epyc-
technical-docs/specifications/57230.pdf>.
[VLEK] Advanced Micro Devices Inc., "Versioned Loaded Endorsement
Key (VLEK) Certificate Definition", Revision 0.10 ,
October 2023,
<https://www.amd.com/content/dam/amd/en/documents/epyc-
technical-docs/user-guides/58369-010-versioned-loaded-
endorsement-key-certificate-definition.pdf>.
Appendix A. CoRIM Extensions CDDL
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$crypto-key-type-choice /= #6.32780(bytes .size 48)
digest = [
alg: (int / text),
val: bytes
]
non-empty<M> = (M) .and ({ + any => any })
semver-version-map = {
&(version: 0): version-core-text,
&(version-scheme: 1): &(semver: 16384)
}
version-core-text = tstr .regexp "[0-9]+\\.[0-9]+\\.[0-9]+"
$$flags-map-extension //= &(
sevsnpvm-policy-smt-allowed: -1,
sevsnpvm-policy-migration-agent-allowed: -2,
sevsnpvm-policy-debug-allowed: -3,
sevsnpvm-policy-single-socket-only: -4,
sevsnpvm-policy-cxl-allowed: -5,
sevsnpvm-policy-mem-aes-256-xts-required: -6,
sevsnpvm-policy-rapl-must-be-disabled: -7,
sevsnpvm-policy-ciphertext-hiding-must-be-enabled: -8,
sevsnpvm-policy-reserved: -47..-9,
)
$version-scheme /= &(sevsnpvm-familyimageid-hex: -1)
$raw-value-type-choice /= uint
$$flags-map-extension //= &(
sevsnphost-smt-enabled: -49,
sevsnphost-tsme-enabled: -50,
sevsnphost-ecc-mem-reported-enabled:-51,
sevsnphost-rapl-disabled: -52,
sevsnphost-ciphertext-hiding-enabled: -53
sevsnphost-reserved: -112..-49
)
tagged-byte = #6.560(bytes1)
tagged-leuint32 = #6.560(bytes4)
tagged-leuint64 = #6.560(bytes8)
tagged-bytes4 = #6.560(bytes4)
tagged-bytes8 = #6.560(bytes8)
tagged-bytes32 = #6.560(bytes16)
tagged-bytes32 = #6.560(bytes32)
tagged-bytes64 = #6.560(bytes64)
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bytes1 = bytes .size 1
bytes2 = bytes .size 2
bytes4 = bytes .size 4
bytes8 = bytes .size 8
bytes16 = bytes .size 16
bytes32 = bytes .size 32
bytes48 = bytes .size 48
bytes64 = bytes .size 64
svn-type = uint
svn = svn-type
min-svn = svn-type
tagged-svn = #6.552(svn)
tagged-min-svn = #6.553(min-svn)
svn-type-choice = tagged-svn / tagged-min-svn
svn64-type = tagged-svn64 / tagged-min-svn64
tagged-svn64 = #6.552(uint64)
tagged-min-svn64 = #6.553(uint64)
uint16 = 0..65535
uint32 = 0..4294967295
uint64 = 0..18446744073709551615
Contributors
Yogesh Deshpande
arm
Email: yogesh.deshpande@arm.com
Yogesh Deshpande contributed to the data model by providing advice
about CoRIM founding principles.
Bill Jacobs
Advanced Micro Devices
Bill contributed a review and the OID assignments on behalf of AMD.
Author's Address
Dionna Glaze
Google LLC
Email: dionnaglaze@google.com
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