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Add GET_EAT Support to OCP Profile #60

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Merged
merged 11 commits into from
Sep 2, 2025
Merged

Add GET_EAT Support to OCP Profile #60

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42474e5
Add GET_EAT Support to OCP Profile
fdamato Aug 22, 2025
ce34bd0
- Create central registry for OCP VENDOR_DEFINED command codes
fdamato Aug 23, 2025
16e6a32
Address Reviews:
fdamato Aug 26, 2025
92ac383
Merge branch 'opencomputeproject:main' into fadamato/get_eat_support
fdamato Aug 27, 2025
65a9c1a
Address OCP Feedback on NONCE length, and remove OCP Command Registry…
fdamato Aug 27, 2025
54c50ee
Address feedback:
fdamato Aug 29, 2025
c0e5003
Address few feedbacks
fdamato Aug 29, 2025
c652dcf
Fix Responder -> Attester
fdamato Sep 2, 2025
3c5f097
Revert ietf-eat-profile/spec.ocp
fdamato Sep 2, 2025
80e730a
Add OCP Command Registry to bibliography.yml
fdamato Sep 2, 2025
43b0440
few stylistic fixes
fdamato Sep 2, 2025
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8 changes: 8 additions & 0 deletions specifications/attestation-of-system-components/bibliography.yaml
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@@ -0,0 +1,8 @@
references:
- id: "ocp-command-registry"
title: "OCP Command Registry"
publisher: "Open Compute Project"
issued:
year: 2025
month: 9
url: "https://github.com/opencomputeproject/ocp-registry/blob/main/command-registry.md"
101 changes: 101 additions & 0 deletions specifications/attestation-of-system-components/spec.ocp
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Expand Up @@ -65,6 +65,7 @@ The Contributors of this Specification would like to acknowledge the following:
- Wojtek Powiertowski, Facebook, Inc.
- Eric Spada, Broadcom, Inc.
- Ben Stoltz, Google
- Fabrizio D'Amato - AMD

<!---
Please describe how this Specification complies with the OCP tenets.
Expand Down Expand Up @@ -558,6 +559,106 @@ May call these "(strongly) recommended"

See <https://github.com/opencomputeproject/Security/tree/main/specifications/ietf-eat-profile>.

# GET_EAT Command

## Overview

The GET_EAT command enables verifiers to obtain attestation evidence from a device in the form of an Entity Attestation Token (EAT) that conforms to the OCP EAT Profile. This command is allocated in the [@{ocp-command-registry}] and is designed to be transport-agnostic while providing a standardized interface for attestation requests.

## Command Definition

The GET_EAT command is assigned command code 0x02 in the [@{ocp-command-registry}].

### GET_EAT Request

+---------------------+---------------------+---------------------+----------------------------------------------+
| Byte offset | Field | Size (bytes) | Description |
+=====================+=====================+=====================+==============================================+
| 0 | CommandVersion | 1 | The version of this request structure. |
| | | | Shall be zero. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 1 | CommandCode | 1 | Shall be 02h to indicate GET_EAT. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 2 | Reserved | 2 | Reserved. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 4 | NonceLength | 1 | Shall be the length of the Nonce field |
| | | | in bytes. Shall be between 8 and 64 bytes. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 5 | Nonce | NonceLength | The Verifier shall choose a random |
| | | | value to ensure freshness. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 5 + NonceLength | SignerSlotID | 1 | Shall be the SlotID. Slot number of the |
| | | | Attester certificate chain that shall |
| | | | be used for signing the EAT. |
+---------------------+---------------------+---------------------+----------------------------------------------+

### GET_EAT Response

For successful responses, the following structure is returned:

+---------------------+---------------------+---------------------+----------------------------------------------+
| Byte offset | Field | Size (bytes) | Description |
+=====================+=====================+=====================+==============================================+
| 0 | CommandVersion | 1 | The version of this response structure. |
| | | | Shall be zero. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 1 | CommandCode | 1 | Shall be 02h to indicate GET_EAT. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 2 | Reserved | 2 | Reserved. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 4 | EATLength | 4 | Shall be the length of the EATToken |
| | | | field in bytes. Note: For large EAT tokens, |
| | | | transport protocols may provide mechanisms |
| | | | such as chunking or streaming to manage |
| | | | buffer limitations. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 8 | EATToken | EATLength | Shall be the Entity Attestation Token |
| | | | conforming to the OCP EAT Profile. |
+---------------------+---------------------+---------------------+----------------------------------------------+

**Note**: Error conditions are reported using transport-specific error mechanisms with error codes from [@{ocp-command-registry}].

## EAT Token Requirements

The EATToken returned in the GET_EAT response **MUST** conform to the OCP EAT Profile specification, which includes:

1. The EAT **MUST** be encoded as a signed CWT (CBOR Web Token)
2. The EAT Profile claim (265) **MUST** be present and contain the OCP Profile OID
3. The Nonce claim (10) **MUST** be present and contain the exact nonce value from the request (matching both value and length)
4. The Measurements claim (273) **MUST** be present and contain concise evidence as defined in the OCP EAT Profile
5. The issuer claim (1) **MUST** be present to bind the EAT to the certificate chain that issued it
6. The rim-locators claim (-70001) **MAY** be present to reference CoRIM locations

**Note:** The nonce claim in the EAT response must preserve both the value and length of the nonce provided in the GET_EAT request to ensure proper freshness verification.

## Transport Bindings

### SPDM Binding

When transported over SPDM, the GET_EAT command utilizes the VENDOR_DEFINED mechanism as specified in the [@{ocp-command-registry}].

For SPDM binding:

- The SignerSlotID field **MUST** correspond to SPDM certificate slot numbers

For detailed SPDM transport binding requirements including:

- VENDOR_DEFINED message structure
- Success and error case handling
- ExtendedErrorData usage
- Command framing specifications

Please refer to the [@{ocp-command-registry}] specification.

### Native Transport Bindings

TSM engines and other transport mechanisms **MAY** define their own bindings for the GET_EAT command, provided they:

- Maintain semantic equivalence of request and response structures
- Preserve all required fields and their meanings
- Implement appropriate error reporting using transport-native mechanisms
- Document any transport-specific adaptations

# Measurement collection and storage

## REQUIREMENTS - What to measure and what not to measure {#sec:requirements-what-to-measure-and-what-not-to-measure}
Expand Down
16 changes: 8 additions & 8 deletions specifications/device-identity-provisioning/spec.ocp
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Expand Up @@ -209,12 +209,12 @@ Table: GET_ENVELOPE_SIGNED_CSR VendorDefinedReqPayload {#tbl:ecsr-req}
+---------------------+---------------------+---------------------+----------------------------------------------+
| Byte offset | Field | Size (bytes) | Description |
+=====================+=====================+=====================+==============================================+
| 0 | CommandCode | 1 | Shall be 01h to indicate |
| | | | GET_ENVELOPE_SIGNED_CSR. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 1 | CommandVersion | 1 | The version of this request structure. |
| 0 | CommandVersion | 1 | The version of this request structure. |
| | | | Shall be zero. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 1 | CommandCode | 1 | Shall be 01h to indicate |
| | | | GET_ENVELOPE_SIGNED_CSR. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 2 | Reserved | 4 | Reserved. |
+---------------------+---------------------+---------------------+----------------------------------------------+
| 6 | Param1 | 1 | KeyPairID. The value of this field |
Expand Down Expand Up @@ -281,12 +281,12 @@ Table: ENVELOPE_SIGNED_CSR VendorDefinedRespPayload {#tbl:ecsr-resp}
| Byte | Field | Size (bytes) | Description |
| offset | | | |
+========+=========================+=========================+==========================================+
| 0 | CommandCode | 1 | Shall be 01h to indicate |
| | | | ENVELOPE_SIGNED_CSR. |
+--------+-------------------------+-------------------------+------------------------------------------+
| 1 | CommandVersion | 1 | The version of this request structure. |
| 0 | CommandVersion | 1 | The version of this request structure. |
| | | | Shall be zero. |
+--------+-------------------------+-------------------------+------------------------------------------+
| 1 | CommandCode | 1 | Shall be 01h to indicate |
| | | | ENVELOPE_SIGNED_CSR. |
+--------+-------------------------+-------------------------+------------------------------------------+
| 2 | Reserved | 4 | Reserved. |
+--------+-------------------------+-------------------------+------------------------------------------+
| 6 | EnvelopeSignedCSRLength | 2 | Shall be the length of the |
Expand Down