SEV-SNP Attestation Shim

A reverse proxy service that terminates TLS and exposes an AMD SEV-SNP attestation report over HTTP.

Features

• TLS termination with automatic certificate management
• AMD SEV-SNP attestation endpoint
• API key validation through an external key server
• Rate limiting per API key
• Path-based access control

Configuration

domains:               # Domain name(s) for TLS certificate (leave empty to generate a self-signed certificate)
  - example.com
upstream-port: 8080    # Required: upstream HTTP port
metrics-port: 8081     # Optional: Prometheus metrics port (disabled if empty)
listen-port: 443       # Port to listen on (default: 443)
paths:                 # Optional: List of allowed paths (default: all)
  - /api/v1
  - /api/v2
staging-ca: false      # Use Let's Encrypt staging environment
control-plane: https://api.example.com
rate-limit: 1          # Requests per second per API key
rate-burst: 2          # Maximum burst size for rate limiting
verbose: true          # Debug logging

Attestation

The shim provides an attestation endpoint at /.well-known/tinfoil-attestation that returns a signed SEV-SNP attestation report. The report includes a SHA-256 hash of the TLS certificate in the user data field, allowing clients to bind a TLS connection to an enclave measurement.

Authorization and Control Plane Integration

For each every request to the upstream (the attestation endpoint is excluded from authorization), the shim will check if the Authorization: Bearer ... header is set and attempt to verify the token agains the configured public key.

Rate Limiting

The rate-limit and rate-burst options can be used to limit the number of requests per second per API key.