cocos/cli/CORIM_GENERATION.md

CoRIM Generation CLI Commands

This document describes the CLI commands for generating CoRIM (Concise Reference Integrity Manifest) attestation policies.

Overview

The cocos-cli policy create-corim command provides subcommands for generating CoRIM policies for different platforms:

• azure: Generate from Azure Attestation Token
• gcp: Generate from GCP endorsements
• snp: Generate for AMD SEV-SNP (direct host generation)
• tdx: Generate for Intel TDX (direct host generation)

Commands

Azure SEV-SNP

Generate CoRIM from an Azure Attestation Token (JWT).

cocos-cli policy create-corim azure --token <path-to-token> [--product <product>]

Flags:

• --token (required): Path to file containing Azure Attestation Token (JWT)
• --product (optional): Processor product name (default: "Milan")

Example:

cocos-cli policy create-corim azure \
  --token /path/to/token.jwt \
  --product Milan \
  > azure-policy.corim

GCP SEV-SNP

Generate CoRIM from GCP SEV-SNP measurement and endorsements.

cocos-cli policy create-corim gcp --measurement <hex> [--vcpu <num>]

Flags:

• --measurement (required): 384-bit measurement hex string
• --vcpu (optional): vCPU number (default: 0)

Example:

cocos-cli policy create-corim gcp \
  --measurement abc123... \
  --vcpu 0 \
  > gcp-policy.corim

SEV-SNP (Direct Host)

Generate CoRIM for AMD SEV-SNP platform directly on the host.

cocos-cli policy create-corim snp [flags]

Flags:

• --measurement (optional): Measurement/Launch Digest (hex string, defaults to zero if not provided)
• --policy (optional): SNP policy flags (default: 0)
• --svn (optional): Security Version Number/TCB (default: 0)
• --product (optional): Processor product name (default: "Milan")
• --host-data (optional): Host data (hex string)
• --launch-tcb (optional): Minimum launch TCB (default: 0)
• --output (optional): Output file path (default: stdout)

Examples:

Generate with defaults (zeroed measurement):

cocos-cli policy create-corim snp \
  --product Milan \
  --output snp-policy.corim

Generate with custom measurement:

cocos-cli policy create-corim snp \
  --measurement abc123def456... \
  --product Genoa \
  --svn 1 \
  --policy 0x30000 \
  --output snp-policy.corim

Generate with host data and launch TCB:

cocos-cli policy create-corim snp \
  --measurement abc123... \
  --host-data deadbeef \
  --launch-tcb 1 \
  --output snp-policy.corim

TDX (Direct Host)

Generate CoRIM for Intel TDX platform directly on the host.

cocos-cli policy create-corim tdx [flags]

Flags:

• --measurement (optional): MRTD measurement (hex string, uses default if not provided)
• --svn (optional): Security Version Number (default: 0)
• --rtmrs (optional): Comma-separated RTMRs (hex)
• --mr-seam (optional): MRSEAM (hex)
• --output (optional): Output file path (default: stdout)

Examples:

Generate with defaults (matches legacy script behavior):

cocos-cli policy create-corim tdx \
  --output tdx-policy.corim

Generate with custom values:

cocos-cli policy create-corim tdx \
  --measurement abc123def456... \
  --rtmrs rtmr0,rtmr1,rtmr2,rtmr3 \
  --mr-seam 789abc... \
  --svn 2 \
  --output tdx-policy.corim

Signing CoRIMs

CoRIMs can be signed using a private key (COSE_Sign1). The generated output will be a COSE-wrapped CoRIM in CBOR format.

Prerequisite: Generate Signing Key

You will need an EC private key (P-256) in PEM format. You can generate one using openssl:

openssl ecparam -name prime256v1 -genkey -noout -out private-key.pem

Signing with CLI

Use the --signing-key flag to sign the CoRIM during generation.

SNP Example:

cocos-cli policy create-corim snp \
  --product Milan \
  --signing-key private-key.pem \
  --output signed-snp.corim

TDX Example:

cocos-cli policy create-corim tdx \
  --signing-key private-key.pem \
  --output signed-tdx.corim

Verification

The output file is a standard COSE_Sign1 message containing the CoRIM. It can be verified using any tool that supports COSE and CoRIM verification, such as the veraison/corim library.

Output Format

All commands output CoRIM in CBOR (Concise Binary Object Representation) format. By default, output is written to stdout, allowing for piping:

# Pipe to file
cocos-cli policy create-corim snp --product Milan > policy.corim

# Pipe to another command
cocos-cli policy create-corim tdx | base64

# Use --output flag
cocos-cli policy create-corim snp --product Milan --output policy.corim

Integration with Manager

The manager service can dynamically generate CoRIM policies using the same underlying generator package. When FetchAttestationPolicy is called:

1. For SNP: Calculates IGVM measurement using the igvmmeasure binary
2. Extracts host data and launch TCB from VM configuration
3. Generates CoRIM using the generator package
4. Returns CBOR-encoded CoRIM

See Also

• Generator Package Documentation
• IGVM Measure Package Documentation
• Manager README